| Index: third_party/sqlite/sqlite-src-3070603/ext/fts3/fts3.c
|
| diff --git a/third_party/sqlite/sqlite-src-3070603/ext/fts3/fts3.c b/third_party/sqlite/sqlite-src-3070603/ext/fts3/fts3.c
|
| new file mode 100644
|
| index 0000000000000000000000000000000000000000..20da05164d2a6cbffb0c2859e4859dadcc75606c
|
| --- /dev/null
|
| +++ b/third_party/sqlite/sqlite-src-3070603/ext/fts3/fts3.c
|
| @@ -0,0 +1,3687 @@
|
| +/*
|
| +** 2006 Oct 10
|
| +**
|
| +** The author disclaims copyright to this source code. In place of
|
| +** a legal notice, here is a blessing:
|
| +**
|
| +** May you do good and not evil.
|
| +** May you find forgiveness for yourself and forgive others.
|
| +** May you share freely, never taking more than you give.
|
| +**
|
| +******************************************************************************
|
| +**
|
| +** This is an SQLite module implementing full-text search.
|
| +*/
|
| +
|
| +/*
|
| +** The code in this file is only compiled if:
|
| +**
|
| +** * The FTS3 module is being built as an extension
|
| +** (in which case SQLITE_CORE is not defined), or
|
| +**
|
| +** * The FTS3 module is being built into the core of
|
| +** SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
|
| +*/
|
| +
|
| +/* The full-text index is stored in a series of b+tree (-like)
|
| +** structures called segments which map terms to doclists. The
|
| +** structures are like b+trees in layout, but are constructed from the
|
| +** bottom up in optimal fashion and are not updatable. Since trees
|
| +** are built from the bottom up, things will be described from the
|
| +** bottom up.
|
| +**
|
| +**
|
| +**** Varints ****
|
| +** The basic unit of encoding is a variable-length integer called a
|
| +** varint. We encode variable-length integers in little-endian order
|
| +** using seven bits * per byte as follows:
|
| +**
|
| +** KEY:
|
| +** A = 0xxxxxxx 7 bits of data and one flag bit
|
| +** B = 1xxxxxxx 7 bits of data and one flag bit
|
| +**
|
| +** 7 bits - A
|
| +** 14 bits - BA
|
| +** 21 bits - BBA
|
| +** and so on.
|
| +**
|
| +** This is similar in concept to how sqlite encodes "varints" but
|
| +** the encoding is not the same. SQLite varints are big-endian
|
| +** are are limited to 9 bytes in length whereas FTS3 varints are
|
| +** little-endian and can be up to 10 bytes in length (in theory).
|
| +**
|
| +** Example encodings:
|
| +**
|
| +** 1: 0x01
|
| +** 127: 0x7f
|
| +** 128: 0x81 0x00
|
| +**
|
| +**
|
| +**** Document lists ****
|
| +** A doclist (document list) holds a docid-sorted list of hits for a
|
| +** given term. Doclists hold docids and associated token positions.
|
| +** A docid is the unique integer identifier for a single document.
|
| +** A position is the index of a word within the document. The first
|
| +** word of the document has a position of 0.
|
| +**
|
| +** FTS3 used to optionally store character offsets using a compile-time
|
| +** option. But that functionality is no longer supported.
|
| +**
|
| +** A doclist is stored like this:
|
| +**
|
| +** array {
|
| +** varint docid;
|
| +** array { (position list for column 0)
|
| +** varint position; (2 more than the delta from previous position)
|
| +** }
|
| +** array {
|
| +** varint POS_COLUMN; (marks start of position list for new column)
|
| +** varint column; (index of new column)
|
| +** array {
|
| +** varint position; (2 more than the delta from previous position)
|
| +** }
|
| +** }
|
| +** varint POS_END; (marks end of positions for this document.
|
| +** }
|
| +**
|
| +** Here, array { X } means zero or more occurrences of X, adjacent in
|
| +** memory. A "position" is an index of a token in the token stream
|
| +** generated by the tokenizer. Note that POS_END and POS_COLUMN occur
|
| +** in the same logical place as the position element, and act as sentinals
|
| +** ending a position list array. POS_END is 0. POS_COLUMN is 1.
|
| +** The positions numbers are not stored literally but rather as two more
|
| +** than the difference from the prior position, or the just the position plus
|
| +** 2 for the first position. Example:
|
| +**
|
| +** label: A B C D E F G H I J K
|
| +** value: 123 5 9 1 1 14 35 0 234 72 0
|
| +**
|
| +** The 123 value is the first docid. For column zero in this document
|
| +** there are two matches at positions 3 and 10 (5-2 and 9-2+3). The 1
|
| +** at D signals the start of a new column; the 1 at E indicates that the
|
| +** new column is column number 1. There are two positions at 12 and 45
|
| +** (14-2 and 35-2+12). The 0 at H indicate the end-of-document. The
|
| +** 234 at I is the next docid. It has one position 72 (72-2) and then
|
| +** terminates with the 0 at K.
|
| +**
|
| +** A "position-list" is the list of positions for multiple columns for
|
| +** a single docid. A "column-list" is the set of positions for a single
|
| +** column. Hence, a position-list consists of one or more column-lists,
|
| +** a document record consists of a docid followed by a position-list and
|
| +** a doclist consists of one or more document records.
|
| +**
|
| +** A bare doclist omits the position information, becoming an
|
| +** array of varint-encoded docids.
|
| +**
|
| +**** Segment leaf nodes ****
|
| +** Segment leaf nodes store terms and doclists, ordered by term. Leaf
|
| +** nodes are written using LeafWriter, and read using LeafReader (to
|
| +** iterate through a single leaf node's data) and LeavesReader (to
|
| +** iterate through a segment's entire leaf layer). Leaf nodes have
|
| +** the format:
|
| +**
|
| +** varint iHeight; (height from leaf level, always 0)
|
| +** varint nTerm; (length of first term)
|
| +** char pTerm[nTerm]; (content of first term)
|
| +** varint nDoclist; (length of term's associated doclist)
|
| +** char pDoclist[nDoclist]; (content of doclist)
|
| +** array {
|
| +** (further terms are delta-encoded)
|
| +** varint nPrefix; (length of prefix shared with previous term)
|
| +** varint nSuffix; (length of unshared suffix)
|
| +** char pTermSuffix[nSuffix];(unshared suffix of next term)
|
| +** varint nDoclist; (length of term's associated doclist)
|
| +** char pDoclist[nDoclist]; (content of doclist)
|
| +** }
|
| +**
|
| +** Here, array { X } means zero or more occurrences of X, adjacent in
|
| +** memory.
|
| +**
|
| +** Leaf nodes are broken into blocks which are stored contiguously in
|
| +** the %_segments table in sorted order. This means that when the end
|
| +** of a node is reached, the next term is in the node with the next
|
| +** greater node id.
|
| +**
|
| +** New data is spilled to a new leaf node when the current node
|
| +** exceeds LEAF_MAX bytes (default 2048). New data which itself is
|
| +** larger than STANDALONE_MIN (default 1024) is placed in a standalone
|
| +** node (a leaf node with a single term and doclist). The goal of
|
| +** these settings is to pack together groups of small doclists while
|
| +** making it efficient to directly access large doclists. The
|
| +** assumption is that large doclists represent terms which are more
|
| +** likely to be query targets.
|
| +**
|
| +** TODO(shess) It may be useful for blocking decisions to be more
|
| +** dynamic. For instance, it may make more sense to have a 2.5k leaf
|
| +** node rather than splitting into 2k and .5k nodes. My intuition is
|
| +** that this might extend through 2x or 4x the pagesize.
|
| +**
|
| +**
|
| +**** Segment interior nodes ****
|
| +** Segment interior nodes store blockids for subtree nodes and terms
|
| +** to describe what data is stored by the each subtree. Interior
|
| +** nodes are written using InteriorWriter, and read using
|
| +** InteriorReader. InteriorWriters are created as needed when
|
| +** SegmentWriter creates new leaf nodes, or when an interior node
|
| +** itself grows too big and must be split. The format of interior
|
| +** nodes:
|
| +**
|
| +** varint iHeight; (height from leaf level, always >0)
|
| +** varint iBlockid; (block id of node's leftmost subtree)
|
| +** optional {
|
| +** varint nTerm; (length of first term)
|
| +** char pTerm[nTerm]; (content of first term)
|
| +** array {
|
| +** (further terms are delta-encoded)
|
| +** varint nPrefix; (length of shared prefix with previous term)
|
| +** varint nSuffix; (length of unshared suffix)
|
| +** char pTermSuffix[nSuffix]; (unshared suffix of next term)
|
| +** }
|
| +** }
|
| +**
|
| +** Here, optional { X } means an optional element, while array { X }
|
| +** means zero or more occurrences of X, adjacent in memory.
|
| +**
|
| +** An interior node encodes n terms separating n+1 subtrees. The
|
| +** subtree blocks are contiguous, so only the first subtree's blockid
|
| +** is encoded. The subtree at iBlockid will contain all terms less
|
| +** than the first term encoded (or all terms if no term is encoded).
|
| +** Otherwise, for terms greater than or equal to pTerm[i] but less
|
| +** than pTerm[i+1], the subtree for that term will be rooted at
|
| +** iBlockid+i. Interior nodes only store enough term data to
|
| +** distinguish adjacent children (if the rightmost term of the left
|
| +** child is "something", and the leftmost term of the right child is
|
| +** "wicked", only "w" is stored).
|
| +**
|
| +** New data is spilled to a new interior node at the same height when
|
| +** the current node exceeds INTERIOR_MAX bytes (default 2048).
|
| +** INTERIOR_MIN_TERMS (default 7) keeps large terms from monopolizing
|
| +** interior nodes and making the tree too skinny. The interior nodes
|
| +** at a given height are naturally tracked by interior nodes at
|
| +** height+1, and so on.
|
| +**
|
| +**
|
| +**** Segment directory ****
|
| +** The segment directory in table %_segdir stores meta-information for
|
| +** merging and deleting segments, and also the root node of the
|
| +** segment's tree.
|
| +**
|
| +** The root node is the top node of the segment's tree after encoding
|
| +** the entire segment, restricted to ROOT_MAX bytes (default 1024).
|
| +** This could be either a leaf node or an interior node. If the top
|
| +** node requires more than ROOT_MAX bytes, it is flushed to %_segments
|
| +** and a new root interior node is generated (which should always fit
|
| +** within ROOT_MAX because it only needs space for 2 varints, the
|
| +** height and the blockid of the previous root).
|
| +**
|
| +** The meta-information in the segment directory is:
|
| +** level - segment level (see below)
|
| +** idx - index within level
|
| +** - (level,idx uniquely identify a segment)
|
| +** start_block - first leaf node
|
| +** leaves_end_block - last leaf node
|
| +** end_block - last block (including interior nodes)
|
| +** root - contents of root node
|
| +**
|
| +** If the root node is a leaf node, then start_block,
|
| +** leaves_end_block, and end_block are all 0.
|
| +**
|
| +**
|
| +**** Segment merging ****
|
| +** To amortize update costs, segments are grouped into levels and
|
| +** merged in batches. Each increase in level represents exponentially
|
| +** more documents.
|
| +**
|
| +** New documents (actually, document updates) are tokenized and
|
| +** written individually (using LeafWriter) to a level 0 segment, with
|
| +** incrementing idx. When idx reaches MERGE_COUNT (default 16), all
|
| +** level 0 segments are merged into a single level 1 segment. Level 1
|
| +** is populated like level 0, and eventually MERGE_COUNT level 1
|
| +** segments are merged to a single level 2 segment (representing
|
| +** MERGE_COUNT^2 updates), and so on.
|
| +**
|
| +** A segment merge traverses all segments at a given level in
|
| +** parallel, performing a straightforward sorted merge. Since segment
|
| +** leaf nodes are written in to the %_segments table in order, this
|
| +** merge traverses the underlying sqlite disk structures efficiently.
|
| +** After the merge, all segment blocks from the merged level are
|
| +** deleted.
|
| +**
|
| +** MERGE_COUNT controls how often we merge segments. 16 seems to be
|
| +** somewhat of a sweet spot for insertion performance. 32 and 64 show
|
| +** very similar performance numbers to 16 on insertion, though they're
|
| +** a tiny bit slower (perhaps due to more overhead in merge-time
|
| +** sorting). 8 is about 20% slower than 16, 4 about 50% slower than
|
| +** 16, 2 about 66% slower than 16.
|
| +**
|
| +** At query time, high MERGE_COUNT increases the number of segments
|
| +** which need to be scanned and merged. For instance, with 100k docs
|
| +** inserted:
|
| +**
|
| +** MERGE_COUNT segments
|
| +** 16 25
|
| +** 8 12
|
| +** 4 10
|
| +** 2 6
|
| +**
|
| +** This appears to have only a moderate impact on queries for very
|
| +** frequent terms (which are somewhat dominated by segment merge
|
| +** costs), and infrequent and non-existent terms still seem to be fast
|
| +** even with many segments.
|
| +**
|
| +** TODO(shess) That said, it would be nice to have a better query-side
|
| +** argument for MERGE_COUNT of 16. Also, it is possible/likely that
|
| +** optimizations to things like doclist merging will swing the sweet
|
| +** spot around.
|
| +**
|
| +**
|
| +**
|
| +**** Handling of deletions and updates ****
|
| +** Since we're using a segmented structure, with no docid-oriented
|
| +** index into the term index, we clearly cannot simply update the term
|
| +** index when a document is deleted or updated. For deletions, we
|
| +** write an empty doclist (varint(docid) varint(POS_END)), for updates
|
| +** we simply write the new doclist. Segment merges overwrite older
|
| +** data for a particular docid with newer data, so deletes or updates
|
| +** will eventually overtake the earlier data and knock it out. The
|
| +** query logic likewise merges doclists so that newer data knocks out
|
| +** older data.
|
| +**
|
| +** TODO(shess) Provide a VACUUM type operation to clear out all
|
| +** deletions and duplications. This would basically be a forced merge
|
| +** into a single segment.
|
| +*/
|
| +
|
| +#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
|
| +
|
| +#if defined(SQLITE_ENABLE_FTS3) && !defined(SQLITE_CORE)
|
| +# define SQLITE_CORE 1
|
| +#endif
|
| +
|
| +#include "fts3Int.h"
|
| +
|
| +#include <assert.h>
|
| +#include <stdlib.h>
|
| +#include <stddef.h>
|
| +#include <stdio.h>
|
| +#include <string.h>
|
| +#include <stdarg.h>
|
| +
|
| +#include "fts3.h"
|
| +#ifndef SQLITE_CORE
|
| +# include "sqlite3ext.h"
|
| + SQLITE_EXTENSION_INIT1
|
| +#endif
|
| +
|
| +/*
|
| +** Write a 64-bit variable-length integer to memory starting at p[0].
|
| +** The length of data written will be between 1 and FTS3_VARINT_MAX bytes.
|
| +** The number of bytes written is returned.
|
| +*/
|
| +int sqlite3Fts3PutVarint(char *p, sqlite_int64 v){
|
| + unsigned char *q = (unsigned char *) p;
|
| + sqlite_uint64 vu = v;
|
| + do{
|
| + *q++ = (unsigned char) ((vu & 0x7f) | 0x80);
|
| + vu >>= 7;
|
| + }while( vu!=0 );
|
| + q[-1] &= 0x7f; /* turn off high bit in final byte */
|
| + assert( q - (unsigned char *)p <= FTS3_VARINT_MAX );
|
| + return (int) (q - (unsigned char *)p);
|
| +}
|
| +
|
| +/*
|
| +** Read a 64-bit variable-length integer from memory starting at p[0].
|
| +** Return the number of bytes read, or 0 on error.
|
| +** The value is stored in *v.
|
| +*/
|
| +int sqlite3Fts3GetVarint(const char *p, sqlite_int64 *v){
|
| + const unsigned char *q = (const unsigned char *) p;
|
| + sqlite_uint64 x = 0, y = 1;
|
| + while( (*q&0x80)==0x80 && q-(unsigned char *)p<FTS3_VARINT_MAX ){
|
| + x += y * (*q++ & 0x7f);
|
| + y <<= 7;
|
| + }
|
| + x += y * (*q++);
|
| + *v = (sqlite_int64) x;
|
| + return (int) (q - (unsigned char *)p);
|
| +}
|
| +
|
| +/*
|
| +** Similar to sqlite3Fts3GetVarint(), except that the output is truncated to a
|
| +** 32-bit integer before it is returned.
|
| +*/
|
| +int sqlite3Fts3GetVarint32(const char *p, int *pi){
|
| + sqlite_int64 i;
|
| + int ret = sqlite3Fts3GetVarint(p, &i);
|
| + *pi = (int) i;
|
| + return ret;
|
| +}
|
| +
|
| +/*
|
| +** Return the number of bytes required to encode v as a varint
|
| +*/
|
| +int sqlite3Fts3VarintLen(sqlite3_uint64 v){
|
| + int i = 0;
|
| + do{
|
| + i++;
|
| + v >>= 7;
|
| + }while( v!=0 );
|
| + return i;
|
| +}
|
| +
|
| +/*
|
| +** Convert an SQL-style quoted string into a normal string by removing
|
| +** the quote characters. The conversion is done in-place. If the
|
| +** input does not begin with a quote character, then this routine
|
| +** is a no-op.
|
| +**
|
| +** Examples:
|
| +**
|
| +** "abc" becomes abc
|
| +** 'xyz' becomes xyz
|
| +** [pqr] becomes pqr
|
| +** `mno` becomes mno
|
| +**
|
| +*/
|
| +void sqlite3Fts3Dequote(char *z){
|
| + char quote; /* Quote character (if any ) */
|
| +
|
| + quote = z[0];
|
| + if( quote=='[' || quote=='\'' || quote=='"' || quote=='`' ){
|
| + int iIn = 1; /* Index of next byte to read from input */
|
| + int iOut = 0; /* Index of next byte to write to output */
|
| +
|
| + /* If the first byte was a '[', then the close-quote character is a ']' */
|
| + if( quote=='[' ) quote = ']';
|
| +
|
| + while( ALWAYS(z[iIn]) ){
|
| + if( z[iIn]==quote ){
|
| + if( z[iIn+1]!=quote ) break;
|
| + z[iOut++] = quote;
|
| + iIn += 2;
|
| + }else{
|
| + z[iOut++] = z[iIn++];
|
| + }
|
| + }
|
| + z[iOut] = '\0';
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Read a single varint from the doclist at *pp and advance *pp to point
|
| +** to the first byte past the end of the varint. Add the value of the varint
|
| +** to *pVal.
|
| +*/
|
| +static void fts3GetDeltaVarint(char **pp, sqlite3_int64 *pVal){
|
| + sqlite3_int64 iVal;
|
| + *pp += sqlite3Fts3GetVarint(*pp, &iVal);
|
| + *pVal += iVal;
|
| +}
|
| +
|
| +/*
|
| +** As long as *pp has not reached its end (pEnd), then do the same
|
| +** as fts3GetDeltaVarint(): read a single varint and add it to *pVal.
|
| +** But if we have reached the end of the varint, just set *pp=0 and
|
| +** leave *pVal unchanged.
|
| +*/
|
| +static void fts3GetDeltaVarint2(char **pp, char *pEnd, sqlite3_int64 *pVal){
|
| + if( *pp>=pEnd ){
|
| + *pp = 0;
|
| + }else{
|
| + fts3GetDeltaVarint(pp, pVal);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** The xDisconnect() virtual table method.
|
| +*/
|
| +static int fts3DisconnectMethod(sqlite3_vtab *pVtab){
|
| + Fts3Table *p = (Fts3Table *)pVtab;
|
| + int i;
|
| +
|
| + assert( p->nPendingData==0 );
|
| + assert( p->pSegments==0 );
|
| +
|
| + /* Free any prepared statements held */
|
| + for(i=0; i<SizeofArray(p->aStmt); i++){
|
| + sqlite3_finalize(p->aStmt[i]);
|
| + }
|
| + sqlite3_free(p->zSegmentsTbl);
|
| + sqlite3_free(p->zReadExprlist);
|
| + sqlite3_free(p->zWriteExprlist);
|
| +
|
| + /* Invoke the tokenizer destructor to free the tokenizer. */
|
| + p->pTokenizer->pModule->xDestroy(p->pTokenizer);
|
| +
|
| + sqlite3_free(p);
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** Construct one or more SQL statements from the format string given
|
| +** and then evaluate those statements. The success code is written
|
| +** into *pRc.
|
| +**
|
| +** If *pRc is initially non-zero then this routine is a no-op.
|
| +*/
|
| +static void fts3DbExec(
|
| + int *pRc, /* Success code */
|
| + sqlite3 *db, /* Database in which to run SQL */
|
| + const char *zFormat, /* Format string for SQL */
|
| + ... /* Arguments to the format string */
|
| +){
|
| + va_list ap;
|
| + char *zSql;
|
| + if( *pRc ) return;
|
| + va_start(ap, zFormat);
|
| + zSql = sqlite3_vmprintf(zFormat, ap);
|
| + va_end(ap);
|
| + if( zSql==0 ){
|
| + *pRc = SQLITE_NOMEM;
|
| + }else{
|
| + *pRc = sqlite3_exec(db, zSql, 0, 0, 0);
|
| + sqlite3_free(zSql);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** The xDestroy() virtual table method.
|
| +*/
|
| +static int fts3DestroyMethod(sqlite3_vtab *pVtab){
|
| + int rc = SQLITE_OK; /* Return code */
|
| + Fts3Table *p = (Fts3Table *)pVtab;
|
| + sqlite3 *db = p->db;
|
| +
|
| + /* Drop the shadow tables */
|
| + fts3DbExec(&rc, db, "DROP TABLE IF EXISTS %Q.'%q_content'", p->zDb, p->zName);
|
| + fts3DbExec(&rc, db, "DROP TABLE IF EXISTS %Q.'%q_segments'", p->zDb,p->zName);
|
| + fts3DbExec(&rc, db, "DROP TABLE IF EXISTS %Q.'%q_segdir'", p->zDb, p->zName);
|
| + fts3DbExec(&rc, db, "DROP TABLE IF EXISTS %Q.'%q_docsize'", p->zDb, p->zName);
|
| + fts3DbExec(&rc, db, "DROP TABLE IF EXISTS %Q.'%q_stat'", p->zDb, p->zName);
|
| +
|
| + /* If everything has worked, invoke fts3DisconnectMethod() to free the
|
| + ** memory associated with the Fts3Table structure and return SQLITE_OK.
|
| + ** Otherwise, return an SQLite error code.
|
| + */
|
| + return (rc==SQLITE_OK ? fts3DisconnectMethod(pVtab) : rc);
|
| +}
|
| +
|
| +
|
| +/*
|
| +** Invoke sqlite3_declare_vtab() to declare the schema for the FTS3 table
|
| +** passed as the first argument. This is done as part of the xConnect()
|
| +** and xCreate() methods.
|
| +**
|
| +** If *pRc is non-zero when this function is called, it is a no-op.
|
| +** Otherwise, if an error occurs, an SQLite error code is stored in *pRc
|
| +** before returning.
|
| +*/
|
| +static void fts3DeclareVtab(int *pRc, Fts3Table *p){
|
| + if( *pRc==SQLITE_OK ){
|
| + int i; /* Iterator variable */
|
| + int rc; /* Return code */
|
| + char *zSql; /* SQL statement passed to declare_vtab() */
|
| + char *zCols; /* List of user defined columns */
|
| +
|
| + /* Create a list of user columns for the virtual table */
|
| + zCols = sqlite3_mprintf("%Q, ", p->azColumn[0]);
|
| + for(i=1; zCols && i<p->nColumn; i++){
|
| + zCols = sqlite3_mprintf("%z%Q, ", zCols, p->azColumn[i]);
|
| + }
|
| +
|
| + /* Create the whole "CREATE TABLE" statement to pass to SQLite */
|
| + zSql = sqlite3_mprintf(
|
| + "CREATE TABLE x(%s %Q HIDDEN, docid HIDDEN)", zCols, p->zName
|
| + );
|
| + if( !zCols || !zSql ){
|
| + rc = SQLITE_NOMEM;
|
| + }else{
|
| + rc = sqlite3_declare_vtab(p->db, zSql);
|
| + }
|
| +
|
| + sqlite3_free(zSql);
|
| + sqlite3_free(zCols);
|
| + *pRc = rc;
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Create the backing store tables (%_content, %_segments and %_segdir)
|
| +** required by the FTS3 table passed as the only argument. This is done
|
| +** as part of the vtab xCreate() method.
|
| +**
|
| +** If the p->bHasDocsize boolean is true (indicating that this is an
|
| +** FTS4 table, not an FTS3 table) then also create the %_docsize and
|
| +** %_stat tables required by FTS4.
|
| +*/
|
| +static int fts3CreateTables(Fts3Table *p){
|
| + int rc = SQLITE_OK; /* Return code */
|
| + int i; /* Iterator variable */
|
| + char *zContentCols; /* Columns of %_content table */
|
| + sqlite3 *db = p->db; /* The database connection */
|
| +
|
| + /* Create a list of user columns for the content table */
|
| + zContentCols = sqlite3_mprintf("docid INTEGER PRIMARY KEY");
|
| + for(i=0; zContentCols && i<p->nColumn; i++){
|
| + char *z = p->azColumn[i];
|
| + zContentCols = sqlite3_mprintf("%z, 'c%d%q'", zContentCols, i, z);
|
| + }
|
| + if( zContentCols==0 ) rc = SQLITE_NOMEM;
|
| +
|
| + /* Create the content table */
|
| + fts3DbExec(&rc, db,
|
| + "CREATE TABLE %Q.'%q_content'(%s)",
|
| + p->zDb, p->zName, zContentCols
|
| + );
|
| + sqlite3_free(zContentCols);
|
| + /* Create other tables */
|
| + fts3DbExec(&rc, db,
|
| + "CREATE TABLE %Q.'%q_segments'(blockid INTEGER PRIMARY KEY, block BLOB);",
|
| + p->zDb, p->zName
|
| + );
|
| + fts3DbExec(&rc, db,
|
| + "CREATE TABLE %Q.'%q_segdir'("
|
| + "level INTEGER,"
|
| + "idx INTEGER,"
|
| + "start_block INTEGER,"
|
| + "leaves_end_block INTEGER,"
|
| + "end_block INTEGER,"
|
| + "root BLOB,"
|
| + "PRIMARY KEY(level, idx)"
|
| + ");",
|
| + p->zDb, p->zName
|
| + );
|
| + if( p->bHasDocsize ){
|
| + fts3DbExec(&rc, db,
|
| + "CREATE TABLE %Q.'%q_docsize'(docid INTEGER PRIMARY KEY, size BLOB);",
|
| + p->zDb, p->zName
|
| + );
|
| + }
|
| + if( p->bHasStat ){
|
| + fts3DbExec(&rc, db,
|
| + "CREATE TABLE %Q.'%q_stat'(id INTEGER PRIMARY KEY, value BLOB);",
|
| + p->zDb, p->zName
|
| + );
|
| + }
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** Store the current database page-size in bytes in p->nPgsz.
|
| +**
|
| +** If *pRc is non-zero when this function is called, it is a no-op.
|
| +** Otherwise, if an error occurs, an SQLite error code is stored in *pRc
|
| +** before returning.
|
| +*/
|
| +static void fts3DatabasePageSize(int *pRc, Fts3Table *p){
|
| + if( *pRc==SQLITE_OK ){
|
| + int rc; /* Return code */
|
| + char *zSql; /* SQL text "PRAGMA %Q.page_size" */
|
| + sqlite3_stmt *pStmt; /* Compiled "PRAGMA %Q.page_size" statement */
|
| +
|
| + zSql = sqlite3_mprintf("PRAGMA %Q.page_size", p->zDb);
|
| + if( !zSql ){
|
| + rc = SQLITE_NOMEM;
|
| + }else{
|
| + rc = sqlite3_prepare(p->db, zSql, -1, &pStmt, 0);
|
| + if( rc==SQLITE_OK ){
|
| + sqlite3_step(pStmt);
|
| + p->nPgsz = sqlite3_column_int(pStmt, 0);
|
| + rc = sqlite3_finalize(pStmt);
|
| + }
|
| + }
|
| + assert( p->nPgsz>0 || rc!=SQLITE_OK );
|
| + sqlite3_free(zSql);
|
| + *pRc = rc;
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** "Special" FTS4 arguments are column specifications of the following form:
|
| +**
|
| +** <key> = <value>
|
| +**
|
| +** There may not be whitespace surrounding the "=" character. The <value>
|
| +** term may be quoted, but the <key> may not.
|
| +*/
|
| +static int fts3IsSpecialColumn(
|
| + const char *z,
|
| + int *pnKey,
|
| + char **pzValue
|
| +){
|
| + char *zValue;
|
| + const char *zCsr = z;
|
| +
|
| + while( *zCsr!='=' ){
|
| + if( *zCsr=='\0' ) return 0;
|
| + zCsr++;
|
| + }
|
| +
|
| + *pnKey = (int)(zCsr-z);
|
| + zValue = sqlite3_mprintf("%s", &zCsr[1]);
|
| + if( zValue ){
|
| + sqlite3Fts3Dequote(zValue);
|
| + }
|
| + *pzValue = zValue;
|
| + return 1;
|
| +}
|
| +
|
| +/*
|
| +** Append the output of a printf() style formatting to an existing string.
|
| +*/
|
| +static void fts3Appendf(
|
| + int *pRc, /* IN/OUT: Error code */
|
| + char **pz, /* IN/OUT: Pointer to string buffer */
|
| + const char *zFormat, /* Printf format string to append */
|
| + ... /* Arguments for printf format string */
|
| +){
|
| + if( *pRc==SQLITE_OK ){
|
| + va_list ap;
|
| + char *z;
|
| + va_start(ap, zFormat);
|
| + z = sqlite3_vmprintf(zFormat, ap);
|
| + if( z && *pz ){
|
| + char *z2 = sqlite3_mprintf("%s%s", *pz, z);
|
| + sqlite3_free(z);
|
| + z = z2;
|
| + }
|
| + if( z==0 ) *pRc = SQLITE_NOMEM;
|
| + sqlite3_free(*pz);
|
| + *pz = z;
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Return a copy of input string zInput enclosed in double-quotes (") and
|
| +** with all double quote characters escaped. For example:
|
| +**
|
| +** fts3QuoteId("un \"zip\"") -> "un \"\"zip\"\""
|
| +**
|
| +** The pointer returned points to memory obtained from sqlite3_malloc(). It
|
| +** is the callers responsibility to call sqlite3_free() to release this
|
| +** memory.
|
| +*/
|
| +static char *fts3QuoteId(char const *zInput){
|
| + int nRet;
|
| + char *zRet;
|
| + nRet = 2 + strlen(zInput)*2 + 1;
|
| + zRet = sqlite3_malloc(nRet);
|
| + if( zRet ){
|
| + int i;
|
| + char *z = zRet;
|
| + *(z++) = '"';
|
| + for(i=0; zInput[i]; i++){
|
| + if( zInput[i]=='"' ) *(z++) = '"';
|
| + *(z++) = zInput[i];
|
| + }
|
| + *(z++) = '"';
|
| + *(z++) = '\0';
|
| + }
|
| + return zRet;
|
| +}
|
| +
|
| +/*
|
| +** Return a list of comma separated SQL expressions that could be used
|
| +** in a SELECT statement such as the following:
|
| +**
|
| +** SELECT <list of expressions> FROM %_content AS x ...
|
| +**
|
| +** to return the docid, followed by each column of text data in order
|
| +** from left to write. If parameter zFunc is not NULL, then instead of
|
| +** being returned directly each column of text data is passed to an SQL
|
| +** function named zFunc first. For example, if zFunc is "unzip" and the
|
| +** table has the three user-defined columns "a", "b", and "c", the following
|
| +** string is returned:
|
| +**
|
| +** "docid, unzip(x.'a'), unzip(x.'b'), unzip(x.'c')"
|
| +**
|
| +** The pointer returned points to a buffer allocated by sqlite3_malloc(). It
|
| +** is the responsibility of the caller to eventually free it.
|
| +**
|
| +** If *pRc is not SQLITE_OK when this function is called, it is a no-op (and
|
| +** a NULL pointer is returned). Otherwise, if an OOM error is encountered
|
| +** by this function, NULL is returned and *pRc is set to SQLITE_NOMEM. If
|
| +** no error occurs, *pRc is left unmodified.
|
| +*/
|
| +static char *fts3ReadExprList(Fts3Table *p, const char *zFunc, int *pRc){
|
| + char *zRet = 0;
|
| + char *zFree = 0;
|
| + char *zFunction;
|
| + int i;
|
| +
|
| + if( !zFunc ){
|
| + zFunction = "";
|
| + }else{
|
| + zFree = zFunction = fts3QuoteId(zFunc);
|
| + }
|
| + fts3Appendf(pRc, &zRet, "docid");
|
| + for(i=0; i<p->nColumn; i++){
|
| + fts3Appendf(pRc, &zRet, ",%s(x.'c%d%q')", zFunction, i, p->azColumn[i]);
|
| + }
|
| + sqlite3_free(zFree);
|
| + return zRet;
|
| +}
|
| +
|
| +/*
|
| +** Return a list of N comma separated question marks, where N is the number
|
| +** of columns in the %_content table (one for the docid plus one for each
|
| +** user-defined text column).
|
| +**
|
| +** If argument zFunc is not NULL, then all but the first question mark
|
| +** is preceded by zFunc and an open bracket, and followed by a closed
|
| +** bracket. For example, if zFunc is "zip" and the FTS3 table has three
|
| +** user-defined text columns, the following string is returned:
|
| +**
|
| +** "?, zip(?), zip(?), zip(?)"
|
| +**
|
| +** The pointer returned points to a buffer allocated by sqlite3_malloc(). It
|
| +** is the responsibility of the caller to eventually free it.
|
| +**
|
| +** If *pRc is not SQLITE_OK when this function is called, it is a no-op (and
|
| +** a NULL pointer is returned). Otherwise, if an OOM error is encountered
|
| +** by this function, NULL is returned and *pRc is set to SQLITE_NOMEM. If
|
| +** no error occurs, *pRc is left unmodified.
|
| +*/
|
| +static char *fts3WriteExprList(Fts3Table *p, const char *zFunc, int *pRc){
|
| + char *zRet = 0;
|
| + char *zFree = 0;
|
| + char *zFunction;
|
| + int i;
|
| +
|
| + if( !zFunc ){
|
| + zFunction = "";
|
| + }else{
|
| + zFree = zFunction = fts3QuoteId(zFunc);
|
| + }
|
| + fts3Appendf(pRc, &zRet, "?");
|
| + for(i=0; i<p->nColumn; i++){
|
| + fts3Appendf(pRc, &zRet, ",%s(?)", zFunction);
|
| + }
|
| + sqlite3_free(zFree);
|
| + return zRet;
|
| +}
|
| +
|
| +/*
|
| +** This function is the implementation of both the xConnect and xCreate
|
| +** methods of the FTS3 virtual table.
|
| +**
|
| +** The argv[] array contains the following:
|
| +**
|
| +** argv[0] -> module name ("fts3" or "fts4")
|
| +** argv[1] -> database name
|
| +** argv[2] -> table name
|
| +** argv[...] -> "column name" and other module argument fields.
|
| +*/
|
| +static int fts3InitVtab(
|
| + int isCreate, /* True for xCreate, false for xConnect */
|
| + sqlite3 *db, /* The SQLite database connection */
|
| + void *pAux, /* Hash table containing tokenizers */
|
| + int argc, /* Number of elements in argv array */
|
| + const char * const *argv, /* xCreate/xConnect argument array */
|
| + sqlite3_vtab **ppVTab, /* Write the resulting vtab structure here */
|
| + char **pzErr /* Write any error message here */
|
| +){
|
| + Fts3Hash *pHash = (Fts3Hash *)pAux;
|
| + Fts3Table *p = 0; /* Pointer to allocated vtab */
|
| + int rc = SQLITE_OK; /* Return code */
|
| + int i; /* Iterator variable */
|
| + int nByte; /* Size of allocation used for *p */
|
| + int iCol; /* Column index */
|
| + int nString = 0; /* Bytes required to hold all column names */
|
| + int nCol = 0; /* Number of columns in the FTS table */
|
| + char *zCsr; /* Space for holding column names */
|
| + int nDb; /* Bytes required to hold database name */
|
| + int nName; /* Bytes required to hold table name */
|
| + int isFts4 = (argv[0][3]=='4'); /* True for FTS4, false for FTS3 */
|
| + int bNoDocsize = 0; /* True to omit %_docsize table */
|
| + const char **aCol; /* Array of column names */
|
| + sqlite3_tokenizer *pTokenizer = 0; /* Tokenizer for this table */
|
| +
|
| + char *zCompress = 0;
|
| + char *zUncompress = 0;
|
| +
|
| + assert( strlen(argv[0])==4 );
|
| + assert( (sqlite3_strnicmp(argv[0], "fts4", 4)==0 && isFts4)
|
| + || (sqlite3_strnicmp(argv[0], "fts3", 4)==0 && !isFts4)
|
| + );
|
| +
|
| + nDb = (int)strlen(argv[1]) + 1;
|
| + nName = (int)strlen(argv[2]) + 1;
|
| +
|
| + aCol = (const char **)sqlite3_malloc(sizeof(const char *) * (argc-2) );
|
| + if( !aCol ) return SQLITE_NOMEM;
|
| + memset((void *)aCol, 0, sizeof(const char *) * (argc-2));
|
| +
|
| + /* Loop through all of the arguments passed by the user to the FTS3/4
|
| + ** module (i.e. all the column names and special arguments). This loop
|
| + ** does the following:
|
| + **
|
| + ** + Figures out the number of columns the FTSX table will have, and
|
| + ** the number of bytes of space that must be allocated to store copies
|
| + ** of the column names.
|
| + **
|
| + ** + If there is a tokenizer specification included in the arguments,
|
| + ** initializes the tokenizer pTokenizer.
|
| + */
|
| + for(i=3; rc==SQLITE_OK && i<argc; i++){
|
| + char const *z = argv[i];
|
| + int nKey;
|
| + char *zVal;
|
| +
|
| + /* Check if this is a tokenizer specification */
|
| + if( !pTokenizer
|
| + && strlen(z)>8
|
| + && 0==sqlite3_strnicmp(z, "tokenize", 8)
|
| + && 0==sqlite3Fts3IsIdChar(z[8])
|
| + ){
|
| + rc = sqlite3Fts3InitTokenizer(pHash, &z[9], &pTokenizer, pzErr);
|
| + }
|
| +
|
| + /* Check if it is an FTS4 special argument. */
|
| + else if( isFts4 && fts3IsSpecialColumn(z, &nKey, &zVal) ){
|
| + if( !zVal ){
|
| + rc = SQLITE_NOMEM;
|
| + goto fts3_init_out;
|
| + }
|
| + if( nKey==9 && 0==sqlite3_strnicmp(z, "matchinfo", 9) ){
|
| + if( strlen(zVal)==4 && 0==sqlite3_strnicmp(zVal, "fts3", 4) ){
|
| + bNoDocsize = 1;
|
| + }else{
|
| + *pzErr = sqlite3_mprintf("unrecognized matchinfo: %s", zVal);
|
| + rc = SQLITE_ERROR;
|
| + }
|
| + }else if( nKey==8 && 0==sqlite3_strnicmp(z, "compress", 8) ){
|
| + zCompress = zVal;
|
| + zVal = 0;
|
| + }else if( nKey==10 && 0==sqlite3_strnicmp(z, "uncompress", 10) ){
|
| + zUncompress = zVal;
|
| + zVal = 0;
|
| + }else{
|
| + *pzErr = sqlite3_mprintf("unrecognized parameter: %s", z);
|
| + rc = SQLITE_ERROR;
|
| + }
|
| + sqlite3_free(zVal);
|
| + }
|
| +
|
| + /* Otherwise, the argument is a column name. */
|
| + else {
|
| + nString += (int)(strlen(z) + 1);
|
| + aCol[nCol++] = z;
|
| + }
|
| + }
|
| + if( rc!=SQLITE_OK ) goto fts3_init_out;
|
| +
|
| + if( nCol==0 ){
|
| + assert( nString==0 );
|
| + aCol[0] = "content";
|
| + nString = 8;
|
| + nCol = 1;
|
| + }
|
| +
|
| + if( pTokenizer==0 ){
|
| + rc = sqlite3Fts3InitTokenizer(pHash, "simple", &pTokenizer, pzErr);
|
| + if( rc!=SQLITE_OK ) goto fts3_init_out;
|
| + }
|
| + assert( pTokenizer );
|
| +
|
| +
|
| + /* Allocate and populate the Fts3Table structure. */
|
| + nByte = sizeof(Fts3Table) + /* Fts3Table */
|
| + nCol * sizeof(char *) + /* azColumn */
|
| + nName + /* zName */
|
| + nDb + /* zDb */
|
| + nString; /* Space for azColumn strings */
|
| + p = (Fts3Table*)sqlite3_malloc(nByte);
|
| + if( p==0 ){
|
| + rc = SQLITE_NOMEM;
|
| + goto fts3_init_out;
|
| + }
|
| + memset(p, 0, nByte);
|
| + p->db = db;
|
| + p->nColumn = nCol;
|
| + p->nPendingData = 0;
|
| + p->azColumn = (char **)&p[1];
|
| + p->pTokenizer = pTokenizer;
|
| + p->nNodeSize = 1000;
|
| + p->nMaxPendingData = FTS3_MAX_PENDING_DATA;
|
| + p->bHasDocsize = (isFts4 && bNoDocsize==0);
|
| + p->bHasStat = isFts4;
|
| + fts3HashInit(&p->pendingTerms, FTS3_HASH_STRING, 1);
|
| +
|
| + /* Fill in the zName and zDb fields of the vtab structure. */
|
| + zCsr = (char *)&p->azColumn[nCol];
|
| + p->zName = zCsr;
|
| + memcpy(zCsr, argv[2], nName);
|
| + zCsr += nName;
|
| + p->zDb = zCsr;
|
| + memcpy(zCsr, argv[1], nDb);
|
| + zCsr += nDb;
|
| +
|
| + /* Fill in the azColumn array */
|
| + for(iCol=0; iCol<nCol; iCol++){
|
| + char *z;
|
| + int n;
|
| + z = (char *)sqlite3Fts3NextToken(aCol[iCol], &n);
|
| + memcpy(zCsr, z, n);
|
| + zCsr[n] = '\0';
|
| + sqlite3Fts3Dequote(zCsr);
|
| + p->azColumn[iCol] = zCsr;
|
| + zCsr += n+1;
|
| + assert( zCsr <= &((char *)p)[nByte] );
|
| + }
|
| +
|
| + if( (zCompress==0)!=(zUncompress==0) ){
|
| + char const *zMiss = (zCompress==0 ? "compress" : "uncompress");
|
| + rc = SQLITE_ERROR;
|
| + *pzErr = sqlite3_mprintf("missing %s parameter in fts4 constructor", zMiss);
|
| + }
|
| + p->zReadExprlist = fts3ReadExprList(p, zUncompress, &rc);
|
| + p->zWriteExprlist = fts3WriteExprList(p, zCompress, &rc);
|
| + if( rc!=SQLITE_OK ) goto fts3_init_out;
|
| +
|
| + /* If this is an xCreate call, create the underlying tables in the
|
| + ** database. TODO: For xConnect(), it could verify that said tables exist.
|
| + */
|
| + if( isCreate ){
|
| + rc = fts3CreateTables(p);
|
| + }
|
| +
|
| + /* Figure out the page-size for the database. This is required in order to
|
| + ** estimate the cost of loading large doclists from the database (see
|
| + ** function sqlite3Fts3SegReaderCost() for details).
|
| + */
|
| + fts3DatabasePageSize(&rc, p);
|
| +
|
| + /* Declare the table schema to SQLite. */
|
| + fts3DeclareVtab(&rc, p);
|
| +
|
| +fts3_init_out:
|
| + sqlite3_free(zCompress);
|
| + sqlite3_free(zUncompress);
|
| + sqlite3_free((void *)aCol);
|
| + if( rc!=SQLITE_OK ){
|
| + if( p ){
|
| + fts3DisconnectMethod((sqlite3_vtab *)p);
|
| + }else if( pTokenizer ){
|
| + pTokenizer->pModule->xDestroy(pTokenizer);
|
| + }
|
| + }else{
|
| + *ppVTab = &p->base;
|
| + }
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** The xConnect() and xCreate() methods for the virtual table. All the
|
| +** work is done in function fts3InitVtab().
|
| +*/
|
| +static int fts3ConnectMethod(
|
| + sqlite3 *db, /* Database connection */
|
| + void *pAux, /* Pointer to tokenizer hash table */
|
| + int argc, /* Number of elements in argv array */
|
| + const char * const *argv, /* xCreate/xConnect argument array */
|
| + sqlite3_vtab **ppVtab, /* OUT: New sqlite3_vtab object */
|
| + char **pzErr /* OUT: sqlite3_malloc'd error message */
|
| +){
|
| + return fts3InitVtab(0, db, pAux, argc, argv, ppVtab, pzErr);
|
| +}
|
| +static int fts3CreateMethod(
|
| + sqlite3 *db, /* Database connection */
|
| + void *pAux, /* Pointer to tokenizer hash table */
|
| + int argc, /* Number of elements in argv array */
|
| + const char * const *argv, /* xCreate/xConnect argument array */
|
| + sqlite3_vtab **ppVtab, /* OUT: New sqlite3_vtab object */
|
| + char **pzErr /* OUT: sqlite3_malloc'd error message */
|
| +){
|
| + return fts3InitVtab(1, db, pAux, argc, argv, ppVtab, pzErr);
|
| +}
|
| +
|
| +/*
|
| +** Implementation of the xBestIndex method for FTS3 tables. There
|
| +** are three possible strategies, in order of preference:
|
| +**
|
| +** 1. Direct lookup by rowid or docid.
|
| +** 2. Full-text search using a MATCH operator on a non-docid column.
|
| +** 3. Linear scan of %_content table.
|
| +*/
|
| +static int fts3BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
|
| + Fts3Table *p = (Fts3Table *)pVTab;
|
| + int i; /* Iterator variable */
|
| + int iCons = -1; /* Index of constraint to use */
|
| +
|
| + /* By default use a full table scan. This is an expensive option,
|
| + ** so search through the constraints to see if a more efficient
|
| + ** strategy is possible.
|
| + */
|
| + pInfo->idxNum = FTS3_FULLSCAN_SEARCH;
|
| + pInfo->estimatedCost = 500000;
|
| + for(i=0; i<pInfo->nConstraint; i++){
|
| + struct sqlite3_index_constraint *pCons = &pInfo->aConstraint[i];
|
| + if( pCons->usable==0 ) continue;
|
| +
|
| + /* A direct lookup on the rowid or docid column. Assign a cost of 1.0. */
|
| + if( pCons->op==SQLITE_INDEX_CONSTRAINT_EQ
|
| + && (pCons->iColumn<0 || pCons->iColumn==p->nColumn+1 )
|
| + ){
|
| + pInfo->idxNum = FTS3_DOCID_SEARCH;
|
| + pInfo->estimatedCost = 1.0;
|
| + iCons = i;
|
| + }
|
| +
|
| + /* A MATCH constraint. Use a full-text search.
|
| + **
|
| + ** If there is more than one MATCH constraint available, use the first
|
| + ** one encountered. If there is both a MATCH constraint and a direct
|
| + ** rowid/docid lookup, prefer the MATCH strategy. This is done even
|
| + ** though the rowid/docid lookup is faster than a MATCH query, selecting
|
| + ** it would lead to an "unable to use function MATCH in the requested
|
| + ** context" error.
|
| + */
|
| + if( pCons->op==SQLITE_INDEX_CONSTRAINT_MATCH
|
| + && pCons->iColumn>=0 && pCons->iColumn<=p->nColumn
|
| + ){
|
| + pInfo->idxNum = FTS3_FULLTEXT_SEARCH + pCons->iColumn;
|
| + pInfo->estimatedCost = 2.0;
|
| + iCons = i;
|
| + break;
|
| + }
|
| + }
|
| +
|
| + if( iCons>=0 ){
|
| + pInfo->aConstraintUsage[iCons].argvIndex = 1;
|
| + pInfo->aConstraintUsage[iCons].omit = 1;
|
| + }
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** Implementation of xOpen method.
|
| +*/
|
| +static int fts3OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
|
| + sqlite3_vtab_cursor *pCsr; /* Allocated cursor */
|
| +
|
| + UNUSED_PARAMETER(pVTab);
|
| +
|
| + /* Allocate a buffer large enough for an Fts3Cursor structure. If the
|
| + ** allocation succeeds, zero it and return SQLITE_OK. Otherwise,
|
| + ** if the allocation fails, return SQLITE_NOMEM.
|
| + */
|
| + *ppCsr = pCsr = (sqlite3_vtab_cursor *)sqlite3_malloc(sizeof(Fts3Cursor));
|
| + if( !pCsr ){
|
| + return SQLITE_NOMEM;
|
| + }
|
| + memset(pCsr, 0, sizeof(Fts3Cursor));
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** Close the cursor. For additional information see the documentation
|
| +** on the xClose method of the virtual table interface.
|
| +*/
|
| +static int fts3CloseMethod(sqlite3_vtab_cursor *pCursor){
|
| + Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
|
| + assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
|
| + sqlite3_finalize(pCsr->pStmt);
|
| + sqlite3Fts3ExprFree(pCsr->pExpr);
|
| + sqlite3Fts3FreeDeferredTokens(pCsr);
|
| + sqlite3_free(pCsr->aDoclist);
|
| + sqlite3_free(pCsr->aMatchinfo);
|
| + sqlite3_free(pCsr);
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** Position the pCsr->pStmt statement so that it is on the row
|
| +** of the %_content table that contains the last match. Return
|
| +** SQLITE_OK on success.
|
| +*/
|
| +static int fts3CursorSeek(sqlite3_context *pContext, Fts3Cursor *pCsr){
|
| + if( pCsr->isRequireSeek ){
|
| + pCsr->isRequireSeek = 0;
|
| + sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iPrevId);
|
| + if( SQLITE_ROW==sqlite3_step(pCsr->pStmt) ){
|
| + return SQLITE_OK;
|
| + }else{
|
| + int rc = sqlite3_reset(pCsr->pStmt);
|
| + if( rc==SQLITE_OK ){
|
| + /* If no row was found and no error has occured, then the %_content
|
| + ** table is missing a row that is present in the full-text index.
|
| + ** The data structures are corrupt.
|
| + */
|
| + rc = SQLITE_CORRUPT;
|
| + }
|
| + pCsr->isEof = 1;
|
| + if( pContext ){
|
| + sqlite3_result_error_code(pContext, rc);
|
| + }
|
| + return rc;
|
| + }
|
| + }else{
|
| + return SQLITE_OK;
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** This function is used to process a single interior node when searching
|
| +** a b-tree for a term or term prefix. The node data is passed to this
|
| +** function via the zNode/nNode parameters. The term to search for is
|
| +** passed in zTerm/nTerm.
|
| +**
|
| +** If piFirst is not NULL, then this function sets *piFirst to the blockid
|
| +** of the child node that heads the sub-tree that may contain the term.
|
| +**
|
| +** If piLast is not NULL, then *piLast is set to the right-most child node
|
| +** that heads a sub-tree that may contain a term for which zTerm/nTerm is
|
| +** a prefix.
|
| +**
|
| +** If an OOM error occurs, SQLITE_NOMEM is returned. Otherwise, SQLITE_OK.
|
| +*/
|
| +static int fts3ScanInteriorNode(
|
| + const char *zTerm, /* Term to select leaves for */
|
| + int nTerm, /* Size of term zTerm in bytes */
|
| + const char *zNode, /* Buffer containing segment interior node */
|
| + int nNode, /* Size of buffer at zNode */
|
| + sqlite3_int64 *piFirst, /* OUT: Selected child node */
|
| + sqlite3_int64 *piLast /* OUT: Selected child node */
|
| +){
|
| + int rc = SQLITE_OK; /* Return code */
|
| + const char *zCsr = zNode; /* Cursor to iterate through node */
|
| + const char *zEnd = &zCsr[nNode];/* End of interior node buffer */
|
| + char *zBuffer = 0; /* Buffer to load terms into */
|
| + int nAlloc = 0; /* Size of allocated buffer */
|
| + int isFirstTerm = 1; /* True when processing first term on page */
|
| + sqlite3_int64 iChild; /* Block id of child node to descend to */
|
| +
|
| + /* Skip over the 'height' varint that occurs at the start of every
|
| + ** interior node. Then load the blockid of the left-child of the b-tree
|
| + ** node into variable iChild.
|
| + **
|
| + ** Even if the data structure on disk is corrupted, this (reading two
|
| + ** varints from the buffer) does not risk an overread. If zNode is a
|
| + ** root node, then the buffer comes from a SELECT statement. SQLite does
|
| + ** not make this guarantee explicitly, but in practice there are always
|
| + ** either more than 20 bytes of allocated space following the nNode bytes of
|
| + ** contents, or two zero bytes. Or, if the node is read from the %_segments
|
| + ** table, then there are always 20 bytes of zeroed padding following the
|
| + ** nNode bytes of content (see sqlite3Fts3ReadBlock() for details).
|
| + */
|
| + zCsr += sqlite3Fts3GetVarint(zCsr, &iChild);
|
| + zCsr += sqlite3Fts3GetVarint(zCsr, &iChild);
|
| + if( zCsr>zEnd ){
|
| + return SQLITE_CORRUPT;
|
| + }
|
| +
|
| + while( zCsr<zEnd && (piFirst || piLast) ){
|
| + int cmp; /* memcmp() result */
|
| + int nSuffix; /* Size of term suffix */
|
| + int nPrefix = 0; /* Size of term prefix */
|
| + int nBuffer; /* Total term size */
|
| +
|
| + /* Load the next term on the node into zBuffer. Use realloc() to expand
|
| + ** the size of zBuffer if required. */
|
| + if( !isFirstTerm ){
|
| + zCsr += sqlite3Fts3GetVarint32(zCsr, &nPrefix);
|
| + }
|
| + isFirstTerm = 0;
|
| + zCsr += sqlite3Fts3GetVarint32(zCsr, &nSuffix);
|
| +
|
| + if( nPrefix<0 || nSuffix<0 || &zCsr[nSuffix]>zEnd ){
|
| + rc = SQLITE_CORRUPT;
|
| + goto finish_scan;
|
| + }
|
| + if( nPrefix+nSuffix>nAlloc ){
|
| + char *zNew;
|
| + nAlloc = (nPrefix+nSuffix) * 2;
|
| + zNew = (char *)sqlite3_realloc(zBuffer, nAlloc);
|
| + if( !zNew ){
|
| + rc = SQLITE_NOMEM;
|
| + goto finish_scan;
|
| + }
|
| + zBuffer = zNew;
|
| + }
|
| + memcpy(&zBuffer[nPrefix], zCsr, nSuffix);
|
| + nBuffer = nPrefix + nSuffix;
|
| + zCsr += nSuffix;
|
| +
|
| + /* Compare the term we are searching for with the term just loaded from
|
| + ** the interior node. If the specified term is greater than or equal
|
| + ** to the term from the interior node, then all terms on the sub-tree
|
| + ** headed by node iChild are smaller than zTerm. No need to search
|
| + ** iChild.
|
| + **
|
| + ** If the interior node term is larger than the specified term, then
|
| + ** the tree headed by iChild may contain the specified term.
|
| + */
|
| + cmp = memcmp(zTerm, zBuffer, (nBuffer>nTerm ? nTerm : nBuffer));
|
| + if( piFirst && (cmp<0 || (cmp==0 && nBuffer>nTerm)) ){
|
| + *piFirst = iChild;
|
| + piFirst = 0;
|
| + }
|
| +
|
| + if( piLast && cmp<0 ){
|
| + *piLast = iChild;
|
| + piLast = 0;
|
| + }
|
| +
|
| + iChild++;
|
| + };
|
| +
|
| + if( piFirst ) *piFirst = iChild;
|
| + if( piLast ) *piLast = iChild;
|
| +
|
| + finish_scan:
|
| + sqlite3_free(zBuffer);
|
| + return rc;
|
| +}
|
| +
|
| +
|
| +/*
|
| +** The buffer pointed to by argument zNode (size nNode bytes) contains an
|
| +** interior node of a b-tree segment. The zTerm buffer (size nTerm bytes)
|
| +** contains a term. This function searches the sub-tree headed by the zNode
|
| +** node for the range of leaf nodes that may contain the specified term
|
| +** or terms for which the specified term is a prefix.
|
| +**
|
| +** If piLeaf is not NULL, then *piLeaf is set to the blockid of the
|
| +** left-most leaf node in the tree that may contain the specified term.
|
| +** If piLeaf2 is not NULL, then *piLeaf2 is set to the blockid of the
|
| +** right-most leaf node that may contain a term for which the specified
|
| +** term is a prefix.
|
| +**
|
| +** It is possible that the range of returned leaf nodes does not contain
|
| +** the specified term or any terms for which it is a prefix. However, if the
|
| +** segment does contain any such terms, they are stored within the identified
|
| +** range. Because this function only inspects interior segment nodes (and
|
| +** never loads leaf nodes into memory), it is not possible to be sure.
|
| +**
|
| +** If an error occurs, an error code other than SQLITE_OK is returned.
|
| +*/
|
| +static int fts3SelectLeaf(
|
| + Fts3Table *p, /* Virtual table handle */
|
| + const char *zTerm, /* Term to select leaves for */
|
| + int nTerm, /* Size of term zTerm in bytes */
|
| + const char *zNode, /* Buffer containing segment interior node */
|
| + int nNode, /* Size of buffer at zNode */
|
| + sqlite3_int64 *piLeaf, /* Selected leaf node */
|
| + sqlite3_int64 *piLeaf2 /* Selected leaf node */
|
| +){
|
| + int rc; /* Return code */
|
| + int iHeight; /* Height of this node in tree */
|
| +
|
| + assert( piLeaf || piLeaf2 );
|
| +
|
| + sqlite3Fts3GetVarint32(zNode, &iHeight);
|
| + rc = fts3ScanInteriorNode(zTerm, nTerm, zNode, nNode, piLeaf, piLeaf2);
|
| + assert( !piLeaf2 || !piLeaf || rc!=SQLITE_OK || (*piLeaf<=*piLeaf2) );
|
| +
|
| + if( rc==SQLITE_OK && iHeight>1 ){
|
| + char *zBlob = 0; /* Blob read from %_segments table */
|
| + int nBlob; /* Size of zBlob in bytes */
|
| +
|
| + if( piLeaf && piLeaf2 && (*piLeaf!=*piLeaf2) ){
|
| + rc = sqlite3Fts3ReadBlock(p, *piLeaf, &zBlob, &nBlob);
|
| + if( rc==SQLITE_OK ){
|
| + rc = fts3SelectLeaf(p, zTerm, nTerm, zBlob, nBlob, piLeaf, 0);
|
| + }
|
| + sqlite3_free(zBlob);
|
| + piLeaf = 0;
|
| + zBlob = 0;
|
| + }
|
| +
|
| + if( rc==SQLITE_OK ){
|
| + rc = sqlite3Fts3ReadBlock(p, piLeaf ? *piLeaf : *piLeaf2, &zBlob, &nBlob);
|
| + }
|
| + if( rc==SQLITE_OK ){
|
| + rc = fts3SelectLeaf(p, zTerm, nTerm, zBlob, nBlob, piLeaf, piLeaf2);
|
| + }
|
| + sqlite3_free(zBlob);
|
| + }
|
| +
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** This function is used to create delta-encoded serialized lists of FTS3
|
| +** varints. Each call to this function appends a single varint to a list.
|
| +*/
|
| +static void fts3PutDeltaVarint(
|
| + char **pp, /* IN/OUT: Output pointer */
|
| + sqlite3_int64 *piPrev, /* IN/OUT: Previous value written to list */
|
| + sqlite3_int64 iVal /* Write this value to the list */
|
| +){
|
| + assert( iVal-*piPrev > 0 || (*piPrev==0 && iVal==0) );
|
| + *pp += sqlite3Fts3PutVarint(*pp, iVal-*piPrev);
|
| + *piPrev = iVal;
|
| +}
|
| +
|
| +/*
|
| +** When this function is called, *ppPoslist is assumed to point to the
|
| +** start of a position-list. After it returns, *ppPoslist points to the
|
| +** first byte after the position-list.
|
| +**
|
| +** A position list is list of positions (delta encoded) and columns for
|
| +** a single document record of a doclist. So, in other words, this
|
| +** routine advances *ppPoslist so that it points to the next docid in
|
| +** the doclist, or to the first byte past the end of the doclist.
|
| +**
|
| +** If pp is not NULL, then the contents of the position list are copied
|
| +** to *pp. *pp is set to point to the first byte past the last byte copied
|
| +** before this function returns.
|
| +*/
|
| +static void fts3PoslistCopy(char **pp, char **ppPoslist){
|
| + char *pEnd = *ppPoslist;
|
| + char c = 0;
|
| +
|
| + /* The end of a position list is marked by a zero encoded as an FTS3
|
| + ** varint. A single POS_END (0) byte. Except, if the 0 byte is preceded by
|
| + ** a byte with the 0x80 bit set, then it is not a varint 0, but the tail
|
| + ** of some other, multi-byte, value.
|
| + **
|
| + ** The following while-loop moves pEnd to point to the first byte that is not
|
| + ** immediately preceded by a byte with the 0x80 bit set. Then increments
|
| + ** pEnd once more so that it points to the byte immediately following the
|
| + ** last byte in the position-list.
|
| + */
|
| + while( *pEnd | c ){
|
| + c = *pEnd++ & 0x80;
|
| + testcase( c!=0 && (*pEnd)==0 );
|
| + }
|
| + pEnd++; /* Advance past the POS_END terminator byte */
|
| +
|
| + if( pp ){
|
| + int n = (int)(pEnd - *ppPoslist);
|
| + char *p = *pp;
|
| + memcpy(p, *ppPoslist, n);
|
| + p += n;
|
| + *pp = p;
|
| + }
|
| + *ppPoslist = pEnd;
|
| +}
|
| +
|
| +/*
|
| +** When this function is called, *ppPoslist is assumed to point to the
|
| +** start of a column-list. After it returns, *ppPoslist points to the
|
| +** to the terminator (POS_COLUMN or POS_END) byte of the column-list.
|
| +**
|
| +** A column-list is list of delta-encoded positions for a single column
|
| +** within a single document within a doclist.
|
| +**
|
| +** The column-list is terminated either by a POS_COLUMN varint (1) or
|
| +** a POS_END varint (0). This routine leaves *ppPoslist pointing to
|
| +** the POS_COLUMN or POS_END that terminates the column-list.
|
| +**
|
| +** If pp is not NULL, then the contents of the column-list are copied
|
| +** to *pp. *pp is set to point to the first byte past the last byte copied
|
| +** before this function returns. The POS_COLUMN or POS_END terminator
|
| +** is not copied into *pp.
|
| +*/
|
| +static void fts3ColumnlistCopy(char **pp, char **ppPoslist){
|
| + char *pEnd = *ppPoslist;
|
| + char c = 0;
|
| +
|
| + /* A column-list is terminated by either a 0x01 or 0x00 byte that is
|
| + ** not part of a multi-byte varint.
|
| + */
|
| + while( 0xFE & (*pEnd | c) ){
|
| + c = *pEnd++ & 0x80;
|
| + testcase( c!=0 && ((*pEnd)&0xfe)==0 );
|
| + }
|
| + if( pp ){
|
| + int n = (int)(pEnd - *ppPoslist);
|
| + char *p = *pp;
|
| + memcpy(p, *ppPoslist, n);
|
| + p += n;
|
| + *pp = p;
|
| + }
|
| + *ppPoslist = pEnd;
|
| +}
|
| +
|
| +/*
|
| +** Value used to signify the end of an position-list. This is safe because
|
| +** it is not possible to have a document with 2^31 terms.
|
| +*/
|
| +#define POSITION_LIST_END 0x7fffffff
|
| +
|
| +/*
|
| +** This function is used to help parse position-lists. When this function is
|
| +** called, *pp may point to the start of the next varint in the position-list
|
| +** being parsed, or it may point to 1 byte past the end of the position-list
|
| +** (in which case **pp will be a terminator bytes POS_END (0) or
|
| +** (1)).
|
| +**
|
| +** If *pp points past the end of the current position-list, set *pi to
|
| +** POSITION_LIST_END and return. Otherwise, read the next varint from *pp,
|
| +** increment the current value of *pi by the value read, and set *pp to
|
| +** point to the next value before returning.
|
| +**
|
| +** Before calling this routine *pi must be initialized to the value of
|
| +** the previous position, or zero if we are reading the first position
|
| +** in the position-list. Because positions are delta-encoded, the value
|
| +** of the previous position is needed in order to compute the value of
|
| +** the next position.
|
| +*/
|
| +static void fts3ReadNextPos(
|
| + char **pp, /* IN/OUT: Pointer into position-list buffer */
|
| + sqlite3_int64 *pi /* IN/OUT: Value read from position-list */
|
| +){
|
| + if( (**pp)&0xFE ){
|
| + fts3GetDeltaVarint(pp, pi);
|
| + *pi -= 2;
|
| + }else{
|
| + *pi = POSITION_LIST_END;
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** If parameter iCol is not 0, write an POS_COLUMN (1) byte followed by
|
| +** the value of iCol encoded as a varint to *pp. This will start a new
|
| +** column list.
|
| +**
|
| +** Set *pp to point to the byte just after the last byte written before
|
| +** returning (do not modify it if iCol==0). Return the total number of bytes
|
| +** written (0 if iCol==0).
|
| +*/
|
| +static int fts3PutColNumber(char **pp, int iCol){
|
| + int n = 0; /* Number of bytes written */
|
| + if( iCol ){
|
| + char *p = *pp; /* Output pointer */
|
| + n = 1 + sqlite3Fts3PutVarint(&p[1], iCol);
|
| + *p = 0x01;
|
| + *pp = &p[n];
|
| + }
|
| + return n;
|
| +}
|
| +
|
| +/*
|
| +** Compute the union of two position lists. The output written
|
| +** into *pp contains all positions of both *pp1 and *pp2 in sorted
|
| +** order and with any duplicates removed. All pointers are
|
| +** updated appropriately. The caller is responsible for insuring
|
| +** that there is enough space in *pp to hold the complete output.
|
| +*/
|
| +static void fts3PoslistMerge(
|
| + char **pp, /* Output buffer */
|
| + char **pp1, /* Left input list */
|
| + char **pp2 /* Right input list */
|
| +){
|
| + char *p = *pp;
|
| + char *p1 = *pp1;
|
| + char *p2 = *pp2;
|
| +
|
| + while( *p1 || *p2 ){
|
| + int iCol1; /* The current column index in pp1 */
|
| + int iCol2; /* The current column index in pp2 */
|
| +
|
| + if( *p1==POS_COLUMN ) sqlite3Fts3GetVarint32(&p1[1], &iCol1);
|
| + else if( *p1==POS_END ) iCol1 = POSITION_LIST_END;
|
| + else iCol1 = 0;
|
| +
|
| + if( *p2==POS_COLUMN ) sqlite3Fts3GetVarint32(&p2[1], &iCol2);
|
| + else if( *p2==POS_END ) iCol2 = POSITION_LIST_END;
|
| + else iCol2 = 0;
|
| +
|
| + if( iCol1==iCol2 ){
|
| + sqlite3_int64 i1 = 0; /* Last position from pp1 */
|
| + sqlite3_int64 i2 = 0; /* Last position from pp2 */
|
| + sqlite3_int64 iPrev = 0;
|
| + int n = fts3PutColNumber(&p, iCol1);
|
| + p1 += n;
|
| + p2 += n;
|
| +
|
| + /* At this point, both p1 and p2 point to the start of column-lists
|
| + ** for the same column (the column with index iCol1 and iCol2).
|
| + ** A column-list is a list of non-negative delta-encoded varints, each
|
| + ** incremented by 2 before being stored. Each list is terminated by a
|
| + ** POS_END (0) or POS_COLUMN (1). The following block merges the two lists
|
| + ** and writes the results to buffer p. p is left pointing to the byte
|
| + ** after the list written. No terminator (POS_END or POS_COLUMN) is
|
| + ** written to the output.
|
| + */
|
| + fts3GetDeltaVarint(&p1, &i1);
|
| + fts3GetDeltaVarint(&p2, &i2);
|
| + do {
|
| + fts3PutDeltaVarint(&p, &iPrev, (i1<i2) ? i1 : i2);
|
| + iPrev -= 2;
|
| + if( i1==i2 ){
|
| + fts3ReadNextPos(&p1, &i1);
|
| + fts3ReadNextPos(&p2, &i2);
|
| + }else if( i1<i2 ){
|
| + fts3ReadNextPos(&p1, &i1);
|
| + }else{
|
| + fts3ReadNextPos(&p2, &i2);
|
| + }
|
| + }while( i1!=POSITION_LIST_END || i2!=POSITION_LIST_END );
|
| + }else if( iCol1<iCol2 ){
|
| + p1 += fts3PutColNumber(&p, iCol1);
|
| + fts3ColumnlistCopy(&p, &p1);
|
| + }else{
|
| + p2 += fts3PutColNumber(&p, iCol2);
|
| + fts3ColumnlistCopy(&p, &p2);
|
| + }
|
| + }
|
| +
|
| + *p++ = POS_END;
|
| + *pp = p;
|
| + *pp1 = p1 + 1;
|
| + *pp2 = p2 + 1;
|
| +}
|
| +
|
| +/*
|
| +** nToken==1 searches for adjacent positions.
|
| +**
|
| +** This function is used to merge two position lists into one. When it is
|
| +** called, *pp1 and *pp2 must both point to position lists. A position-list is
|
| +** the part of a doclist that follows each document id. For example, if a row
|
| +** contains:
|
| +**
|
| +** 'a b c'|'x y z'|'a b b a'
|
| +**
|
| +** Then the position list for this row for token 'b' would consist of:
|
| +**
|
| +** 0x02 0x01 0x02 0x03 0x03 0x00
|
| +**
|
| +** When this function returns, both *pp1 and *pp2 are left pointing to the
|
| +** byte following the 0x00 terminator of their respective position lists.
|
| +**
|
| +** If isSaveLeft is 0, an entry is added to the output position list for
|
| +** each position in *pp2 for which there exists one or more positions in
|
| +** *pp1 so that (pos(*pp2)>pos(*pp1) && pos(*pp2)-pos(*pp1)<=nToken). i.e.
|
| +** when the *pp1 token appears before the *pp2 token, but not more than nToken
|
| +** slots before it.
|
| +*/
|
| +static int fts3PoslistPhraseMerge(
|
| + char **pp, /* IN/OUT: Preallocated output buffer */
|
| + int nToken, /* Maximum difference in token positions */
|
| + int isSaveLeft, /* Save the left position */
|
| + int isExact, /* If *pp1 is exactly nTokens before *pp2 */
|
| + char **pp1, /* IN/OUT: Left input list */
|
| + char **pp2 /* IN/OUT: Right input list */
|
| +){
|
| + char *p = (pp ? *pp : 0);
|
| + char *p1 = *pp1;
|
| + char *p2 = *pp2;
|
| + int iCol1 = 0;
|
| + int iCol2 = 0;
|
| +
|
| + /* Never set both isSaveLeft and isExact for the same invocation. */
|
| + assert( isSaveLeft==0 || isExact==0 );
|
| +
|
| + assert( *p1!=0 && *p2!=0 );
|
| + if( *p1==POS_COLUMN ){
|
| + p1++;
|
| + p1 += sqlite3Fts3GetVarint32(p1, &iCol1);
|
| + }
|
| + if( *p2==POS_COLUMN ){
|
| + p2++;
|
| + p2 += sqlite3Fts3GetVarint32(p2, &iCol2);
|
| + }
|
| +
|
| + while( 1 ){
|
| + if( iCol1==iCol2 ){
|
| + char *pSave = p;
|
| + sqlite3_int64 iPrev = 0;
|
| + sqlite3_int64 iPos1 = 0;
|
| + sqlite3_int64 iPos2 = 0;
|
| +
|
| + if( pp && iCol1 ){
|
| + *p++ = POS_COLUMN;
|
| + p += sqlite3Fts3PutVarint(p, iCol1);
|
| + }
|
| +
|
| + assert( *p1!=POS_END && *p1!=POS_COLUMN );
|
| + assert( *p2!=POS_END && *p2!=POS_COLUMN );
|
| + fts3GetDeltaVarint(&p1, &iPos1); iPos1 -= 2;
|
| + fts3GetDeltaVarint(&p2, &iPos2); iPos2 -= 2;
|
| +
|
| + while( 1 ){
|
| + if( iPos2==iPos1+nToken
|
| + || (isExact==0 && iPos2>iPos1 && iPos2<=iPos1+nToken)
|
| + ){
|
| + sqlite3_int64 iSave;
|
| + if( !pp ){
|
| + fts3PoslistCopy(0, &p2);
|
| + fts3PoslistCopy(0, &p1);
|
| + *pp1 = p1;
|
| + *pp2 = p2;
|
| + return 1;
|
| + }
|
| + iSave = isSaveLeft ? iPos1 : iPos2;
|
| + fts3PutDeltaVarint(&p, &iPrev, iSave+2); iPrev -= 2;
|
| + pSave = 0;
|
| + }
|
| + if( (!isSaveLeft && iPos2<=(iPos1+nToken)) || iPos2<=iPos1 ){
|
| + if( (*p2&0xFE)==0 ) break;
|
| + fts3GetDeltaVarint(&p2, &iPos2); iPos2 -= 2;
|
| + }else{
|
| + if( (*p1&0xFE)==0 ) break;
|
| + fts3GetDeltaVarint(&p1, &iPos1); iPos1 -= 2;
|
| + }
|
| + }
|
| +
|
| + if( pSave ){
|
| + assert( pp && p );
|
| + p = pSave;
|
| + }
|
| +
|
| + fts3ColumnlistCopy(0, &p1);
|
| + fts3ColumnlistCopy(0, &p2);
|
| + assert( (*p1&0xFE)==0 && (*p2&0xFE)==0 );
|
| + if( 0==*p1 || 0==*p2 ) break;
|
| +
|
| + p1++;
|
| + p1 += sqlite3Fts3GetVarint32(p1, &iCol1);
|
| + p2++;
|
| + p2 += sqlite3Fts3GetVarint32(p2, &iCol2);
|
| + }
|
| +
|
| + /* Advance pointer p1 or p2 (whichever corresponds to the smaller of
|
| + ** iCol1 and iCol2) so that it points to either the 0x00 that marks the
|
| + ** end of the position list, or the 0x01 that precedes the next
|
| + ** column-number in the position list.
|
| + */
|
| + else if( iCol1<iCol2 ){
|
| + fts3ColumnlistCopy(0, &p1);
|
| + if( 0==*p1 ) break;
|
| + p1++;
|
| + p1 += sqlite3Fts3GetVarint32(p1, &iCol1);
|
| + }else{
|
| + fts3ColumnlistCopy(0, &p2);
|
| + if( 0==*p2 ) break;
|
| + p2++;
|
| + p2 += sqlite3Fts3GetVarint32(p2, &iCol2);
|
| + }
|
| + }
|
| +
|
| + fts3PoslistCopy(0, &p2);
|
| + fts3PoslistCopy(0, &p1);
|
| + *pp1 = p1;
|
| + *pp2 = p2;
|
| + if( !pp || *pp==p ){
|
| + return 0;
|
| + }
|
| + *p++ = 0x00;
|
| + *pp = p;
|
| + return 1;
|
| +}
|
| +
|
| +/*
|
| +** Merge two position-lists as required by the NEAR operator.
|
| +*/
|
| +static int fts3PoslistNearMerge(
|
| + char **pp, /* Output buffer */
|
| + char *aTmp, /* Temporary buffer space */
|
| + int nRight, /* Maximum difference in token positions */
|
| + int nLeft, /* Maximum difference in token positions */
|
| + char **pp1, /* IN/OUT: Left input list */
|
| + char **pp2 /* IN/OUT: Right input list */
|
| +){
|
| + char *p1 = *pp1;
|
| + char *p2 = *pp2;
|
| +
|
| + if( !pp ){
|
| + if( fts3PoslistPhraseMerge(0, nRight, 0, 0, pp1, pp2) ) return 1;
|
| + *pp1 = p1;
|
| + *pp2 = p2;
|
| + return fts3PoslistPhraseMerge(0, nLeft, 0, 0, pp2, pp1);
|
| + }else{
|
| + char *pTmp1 = aTmp;
|
| + char *pTmp2;
|
| + char *aTmp2;
|
| + int res = 1;
|
| +
|
| + fts3PoslistPhraseMerge(&pTmp1, nRight, 0, 0, pp1, pp2);
|
| + aTmp2 = pTmp2 = pTmp1;
|
| + *pp1 = p1;
|
| + *pp2 = p2;
|
| + fts3PoslistPhraseMerge(&pTmp2, nLeft, 1, 0, pp2, pp1);
|
| + if( pTmp1!=aTmp && pTmp2!=aTmp2 ){
|
| + fts3PoslistMerge(pp, &aTmp, &aTmp2);
|
| + }else if( pTmp1!=aTmp ){
|
| + fts3PoslistCopy(pp, &aTmp);
|
| + }else if( pTmp2!=aTmp2 ){
|
| + fts3PoslistCopy(pp, &aTmp2);
|
| + }else{
|
| + res = 0;
|
| + }
|
| +
|
| + return res;
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Values that may be used as the first parameter to fts3DoclistMerge().
|
| +*/
|
| +#define MERGE_NOT 2 /* D + D -> D */
|
| +#define MERGE_AND 3 /* D + D -> D */
|
| +#define MERGE_OR 4 /* D + D -> D */
|
| +#define MERGE_POS_OR 5 /* P + P -> P */
|
| +#define MERGE_PHRASE 6 /* P + P -> D */
|
| +#define MERGE_POS_PHRASE 7 /* P + P -> P */
|
| +#define MERGE_NEAR 8 /* P + P -> D */
|
| +#define MERGE_POS_NEAR 9 /* P + P -> P */
|
| +
|
| +/*
|
| +** Merge the two doclists passed in buffer a1 (size n1 bytes) and a2
|
| +** (size n2 bytes). The output is written to pre-allocated buffer aBuffer,
|
| +** which is guaranteed to be large enough to hold the results. The number
|
| +** of bytes written to aBuffer is stored in *pnBuffer before returning.
|
| +**
|
| +** If successful, SQLITE_OK is returned. Otherwise, if a malloc error
|
| +** occurs while allocating a temporary buffer as part of the merge operation,
|
| +** SQLITE_NOMEM is returned.
|
| +*/
|
| +static int fts3DoclistMerge(
|
| + int mergetype, /* One of the MERGE_XXX constants */
|
| + int nParam1, /* Used by MERGE_NEAR and MERGE_POS_NEAR */
|
| + int nParam2, /* Used by MERGE_NEAR and MERGE_POS_NEAR */
|
| + char *aBuffer, /* Pre-allocated output buffer */
|
| + int *pnBuffer, /* OUT: Bytes written to aBuffer */
|
| + char *a1, /* Buffer containing first doclist */
|
| + int n1, /* Size of buffer a1 */
|
| + char *a2, /* Buffer containing second doclist */
|
| + int n2, /* Size of buffer a2 */
|
| + int *pnDoc /* OUT: Number of docids in output */
|
| +){
|
| + sqlite3_int64 i1 = 0;
|
| + sqlite3_int64 i2 = 0;
|
| + sqlite3_int64 iPrev = 0;
|
| +
|
| + char *p = aBuffer;
|
| + char *p1 = a1;
|
| + char *p2 = a2;
|
| + char *pEnd1 = &a1[n1];
|
| + char *pEnd2 = &a2[n2];
|
| + int nDoc = 0;
|
| +
|
| + assert( mergetype==MERGE_OR || mergetype==MERGE_POS_OR
|
| + || mergetype==MERGE_AND || mergetype==MERGE_NOT
|
| + || mergetype==MERGE_PHRASE || mergetype==MERGE_POS_PHRASE
|
| + || mergetype==MERGE_NEAR || mergetype==MERGE_POS_NEAR
|
| + );
|
| +
|
| + if( !aBuffer ){
|
| + *pnBuffer = 0;
|
| + return SQLITE_NOMEM;
|
| + }
|
| +
|
| + /* Read the first docid from each doclist */
|
| + fts3GetDeltaVarint2(&p1, pEnd1, &i1);
|
| + fts3GetDeltaVarint2(&p2, pEnd2, &i2);
|
| +
|
| + switch( mergetype ){
|
| + case MERGE_OR:
|
| + case MERGE_POS_OR:
|
| + while( p1 || p2 ){
|
| + if( p2 && p1 && i1==i2 ){
|
| + fts3PutDeltaVarint(&p, &iPrev, i1);
|
| + if( mergetype==MERGE_POS_OR ) fts3PoslistMerge(&p, &p1, &p2);
|
| + fts3GetDeltaVarint2(&p1, pEnd1, &i1);
|
| + fts3GetDeltaVarint2(&p2, pEnd2, &i2);
|
| + }else if( !p2 || (p1 && i1<i2) ){
|
| + fts3PutDeltaVarint(&p, &iPrev, i1);
|
| + if( mergetype==MERGE_POS_OR ) fts3PoslistCopy(&p, &p1);
|
| + fts3GetDeltaVarint2(&p1, pEnd1, &i1);
|
| + }else{
|
| + fts3PutDeltaVarint(&p, &iPrev, i2);
|
| + if( mergetype==MERGE_POS_OR ) fts3PoslistCopy(&p, &p2);
|
| + fts3GetDeltaVarint2(&p2, pEnd2, &i2);
|
| + }
|
| + }
|
| + break;
|
| +
|
| + case MERGE_AND:
|
| + while( p1 && p2 ){
|
| + if( i1==i2 ){
|
| + fts3PutDeltaVarint(&p, &iPrev, i1);
|
| + fts3GetDeltaVarint2(&p1, pEnd1, &i1);
|
| + fts3GetDeltaVarint2(&p2, pEnd2, &i2);
|
| + nDoc++;
|
| + }else if( i1<i2 ){
|
| + fts3GetDeltaVarint2(&p1, pEnd1, &i1);
|
| + }else{
|
| + fts3GetDeltaVarint2(&p2, pEnd2, &i2);
|
| + }
|
| + }
|
| + break;
|
| +
|
| + case MERGE_NOT:
|
| + while( p1 ){
|
| + if( p2 && i1==i2 ){
|
| + fts3GetDeltaVarint2(&p1, pEnd1, &i1);
|
| + fts3GetDeltaVarint2(&p2, pEnd2, &i2);
|
| + }else if( !p2 || i1<i2 ){
|
| + fts3PutDeltaVarint(&p, &iPrev, i1);
|
| + fts3GetDeltaVarint2(&p1, pEnd1, &i1);
|
| + }else{
|
| + fts3GetDeltaVarint2(&p2, pEnd2, &i2);
|
| + }
|
| + }
|
| + break;
|
| +
|
| + case MERGE_POS_PHRASE:
|
| + case MERGE_PHRASE: {
|
| + char **ppPos = (mergetype==MERGE_PHRASE ? 0 : &p);
|
| + while( p1 && p2 ){
|
| + if( i1==i2 ){
|
| + char *pSave = p;
|
| + sqlite3_int64 iPrevSave = iPrev;
|
| + fts3PutDeltaVarint(&p, &iPrev, i1);
|
| + if( 0==fts3PoslistPhraseMerge(ppPos, nParam1, 0, 1, &p1, &p2) ){
|
| + p = pSave;
|
| + iPrev = iPrevSave;
|
| + }else{
|
| + nDoc++;
|
| + }
|
| + fts3GetDeltaVarint2(&p1, pEnd1, &i1);
|
| + fts3GetDeltaVarint2(&p2, pEnd2, &i2);
|
| + }else if( i1<i2 ){
|
| + fts3PoslistCopy(0, &p1);
|
| + fts3GetDeltaVarint2(&p1, pEnd1, &i1);
|
| + }else{
|
| + fts3PoslistCopy(0, &p2);
|
| + fts3GetDeltaVarint2(&p2, pEnd2, &i2);
|
| + }
|
| + }
|
| + break;
|
| + }
|
| +
|
| + default: assert( mergetype==MERGE_POS_NEAR || mergetype==MERGE_NEAR ); {
|
| + char *aTmp = 0;
|
| + char **ppPos = 0;
|
| +
|
| + if( mergetype==MERGE_POS_NEAR ){
|
| + ppPos = &p;
|
| + aTmp = sqlite3_malloc(2*(n1+n2+1));
|
| + if( !aTmp ){
|
| + return SQLITE_NOMEM;
|
| + }
|
| + }
|
| +
|
| + while( p1 && p2 ){
|
| + if( i1==i2 ){
|
| + char *pSave = p;
|
| + sqlite3_int64 iPrevSave = iPrev;
|
| + fts3PutDeltaVarint(&p, &iPrev, i1);
|
| +
|
| + if( !fts3PoslistNearMerge(ppPos, aTmp, nParam1, nParam2, &p1, &p2) ){
|
| + iPrev = iPrevSave;
|
| + p = pSave;
|
| + }
|
| +
|
| + fts3GetDeltaVarint2(&p1, pEnd1, &i1);
|
| + fts3GetDeltaVarint2(&p2, pEnd2, &i2);
|
| + }else if( i1<i2 ){
|
| + fts3PoslistCopy(0, &p1);
|
| + fts3GetDeltaVarint2(&p1, pEnd1, &i1);
|
| + }else{
|
| + fts3PoslistCopy(0, &p2);
|
| + fts3GetDeltaVarint2(&p2, pEnd2, &i2);
|
| + }
|
| + }
|
| + sqlite3_free(aTmp);
|
| + break;
|
| + }
|
| + }
|
| +
|
| + if( pnDoc ) *pnDoc = nDoc;
|
| + *pnBuffer = (int)(p-aBuffer);
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** A pointer to an instance of this structure is used as the context
|
| +** argument to sqlite3Fts3SegReaderIterate()
|
| +*/
|
| +typedef struct TermSelect TermSelect;
|
| +struct TermSelect {
|
| + int isReqPos;
|
| + char *aaOutput[16]; /* Malloc'd output buffer */
|
| + int anOutput[16]; /* Size of output in bytes */
|
| +};
|
| +
|
| +/*
|
| +** Merge all doclists in the TermSelect.aaOutput[] array into a single
|
| +** doclist stored in TermSelect.aaOutput[0]. If successful, delete all
|
| +** other doclists (except the aaOutput[0] one) and return SQLITE_OK.
|
| +**
|
| +** If an OOM error occurs, return SQLITE_NOMEM. In this case it is
|
| +** the responsibility of the caller to free any doclists left in the
|
| +** TermSelect.aaOutput[] array.
|
| +*/
|
| +static int fts3TermSelectMerge(TermSelect *pTS){
|
| + int mergetype = (pTS->isReqPos ? MERGE_POS_OR : MERGE_OR);
|
| + char *aOut = 0;
|
| + int nOut = 0;
|
| + int i;
|
| +
|
| + /* Loop through the doclists in the aaOutput[] array. Merge them all
|
| + ** into a single doclist.
|
| + */
|
| + for(i=0; i<SizeofArray(pTS->aaOutput); i++){
|
| + if( pTS->aaOutput[i] ){
|
| + if( !aOut ){
|
| + aOut = pTS->aaOutput[i];
|
| + nOut = pTS->anOutput[i];
|
| + pTS->aaOutput[i] = 0;
|
| + }else{
|
| + int nNew = nOut + pTS->anOutput[i];
|
| + char *aNew = sqlite3_malloc(nNew);
|
| + if( !aNew ){
|
| + sqlite3_free(aOut);
|
| + return SQLITE_NOMEM;
|
| + }
|
| + fts3DoclistMerge(mergetype, 0, 0,
|
| + aNew, &nNew, pTS->aaOutput[i], pTS->anOutput[i], aOut, nOut, 0
|
| + );
|
| + sqlite3_free(pTS->aaOutput[i]);
|
| + sqlite3_free(aOut);
|
| + pTS->aaOutput[i] = 0;
|
| + aOut = aNew;
|
| + nOut = nNew;
|
| + }
|
| + }
|
| + }
|
| +
|
| + pTS->aaOutput[0] = aOut;
|
| + pTS->anOutput[0] = nOut;
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** This function is used as the sqlite3Fts3SegReaderIterate() callback when
|
| +** querying the full-text index for a doclist associated with a term or
|
| +** term-prefix.
|
| +*/
|
| +static int fts3TermSelectCb(
|
| + Fts3Table *p, /* Virtual table object */
|
| + void *pContext, /* Pointer to TermSelect structure */
|
| + char *zTerm,
|
| + int nTerm,
|
| + char *aDoclist,
|
| + int nDoclist
|
| +){
|
| + TermSelect *pTS = (TermSelect *)pContext;
|
| +
|
| + UNUSED_PARAMETER(p);
|
| + UNUSED_PARAMETER(zTerm);
|
| + UNUSED_PARAMETER(nTerm);
|
| +
|
| + if( pTS->aaOutput[0]==0 ){
|
| + /* If this is the first term selected, copy the doclist to the output
|
| + ** buffer using memcpy(). TODO: Add a way to transfer control of the
|
| + ** aDoclist buffer from the caller so as to avoid the memcpy().
|
| + */
|
| + pTS->aaOutput[0] = sqlite3_malloc(nDoclist);
|
| + pTS->anOutput[0] = nDoclist;
|
| + if( pTS->aaOutput[0] ){
|
| + memcpy(pTS->aaOutput[0], aDoclist, nDoclist);
|
| + }else{
|
| + return SQLITE_NOMEM;
|
| + }
|
| + }else{
|
| + int mergetype = (pTS->isReqPos ? MERGE_POS_OR : MERGE_OR);
|
| + char *aMerge = aDoclist;
|
| + int nMerge = nDoclist;
|
| + int iOut;
|
| +
|
| + for(iOut=0; iOut<SizeofArray(pTS->aaOutput); iOut++){
|
| + char *aNew;
|
| + int nNew;
|
| + if( pTS->aaOutput[iOut]==0 ){
|
| + assert( iOut>0 );
|
| + pTS->aaOutput[iOut] = aMerge;
|
| + pTS->anOutput[iOut] = nMerge;
|
| + break;
|
| + }
|
| +
|
| + nNew = nMerge + pTS->anOutput[iOut];
|
| + aNew = sqlite3_malloc(nNew);
|
| + if( !aNew ){
|
| + if( aMerge!=aDoclist ){
|
| + sqlite3_free(aMerge);
|
| + }
|
| + return SQLITE_NOMEM;
|
| + }
|
| + fts3DoclistMerge(mergetype, 0, 0, aNew, &nNew,
|
| + pTS->aaOutput[iOut], pTS->anOutput[iOut], aMerge, nMerge, 0
|
| + );
|
| +
|
| + if( iOut>0 ) sqlite3_free(aMerge);
|
| + sqlite3_free(pTS->aaOutput[iOut]);
|
| + pTS->aaOutput[iOut] = 0;
|
| +
|
| + aMerge = aNew;
|
| + nMerge = nNew;
|
| + if( (iOut+1)==SizeofArray(pTS->aaOutput) ){
|
| + pTS->aaOutput[iOut] = aMerge;
|
| + pTS->anOutput[iOut] = nMerge;
|
| + }
|
| + }
|
| + }
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +static int fts3DeferredTermSelect(
|
| + Fts3DeferredToken *pToken, /* Phrase token */
|
| + int isTermPos, /* True to include positions */
|
| + int *pnOut, /* OUT: Size of list */
|
| + char **ppOut /* OUT: Body of list */
|
| +){
|
| + char *aSource;
|
| + int nSource;
|
| +
|
| + aSource = sqlite3Fts3DeferredDoclist(pToken, &nSource);
|
| + if( !aSource ){
|
| + *pnOut = 0;
|
| + *ppOut = 0;
|
| + }else if( isTermPos ){
|
| + *ppOut = sqlite3_malloc(nSource);
|
| + if( !*ppOut ) return SQLITE_NOMEM;
|
| + memcpy(*ppOut, aSource, nSource);
|
| + *pnOut = nSource;
|
| + }else{
|
| + sqlite3_int64 docid;
|
| + *pnOut = sqlite3Fts3GetVarint(aSource, &docid);
|
| + *ppOut = sqlite3_malloc(*pnOut);
|
| + if( !*ppOut ) return SQLITE_NOMEM;
|
| + sqlite3Fts3PutVarint(*ppOut, docid);
|
| + }
|
| +
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +int sqlite3Fts3SegReaderCursor(
|
| + Fts3Table *p, /* FTS3 table handle */
|
| + int iLevel, /* Level of segments to scan */
|
| + const char *zTerm, /* Term to query for */
|
| + int nTerm, /* Size of zTerm in bytes */
|
| + int isPrefix, /* True for a prefix search */
|
| + int isScan, /* True to scan from zTerm to EOF */
|
| + Fts3SegReaderCursor *pCsr /* Cursor object to populate */
|
| +){
|
| + int rc = SQLITE_OK;
|
| + int rc2;
|
| + int iAge = 0;
|
| + sqlite3_stmt *pStmt = 0;
|
| + Fts3SegReader *pPending = 0;
|
| +
|
| + assert( iLevel==FTS3_SEGCURSOR_ALL
|
| + || iLevel==FTS3_SEGCURSOR_PENDING
|
| + || iLevel>=0
|
| + );
|
| + assert( FTS3_SEGCURSOR_PENDING<0 );
|
| + assert( FTS3_SEGCURSOR_ALL<0 );
|
| + assert( iLevel==FTS3_SEGCURSOR_ALL || (zTerm==0 && isPrefix==1) );
|
| + assert( isPrefix==0 || isScan==0 );
|
| +
|
| +
|
| + memset(pCsr, 0, sizeof(Fts3SegReaderCursor));
|
| +
|
| + /* If iLevel is less than 0, include a seg-reader for the pending-terms. */
|
| + assert( isScan==0 || fts3HashCount(&p->pendingTerms)==0 );
|
| + if( iLevel<0 && isScan==0 ){
|
| + rc = sqlite3Fts3SegReaderPending(p, zTerm, nTerm, isPrefix, &pPending);
|
| + if( rc==SQLITE_OK && pPending ){
|
| + int nByte = (sizeof(Fts3SegReader *) * 16);
|
| + pCsr->apSegment = (Fts3SegReader **)sqlite3_malloc(nByte);
|
| + if( pCsr->apSegment==0 ){
|
| + rc = SQLITE_NOMEM;
|
| + }else{
|
| + pCsr->apSegment[0] = pPending;
|
| + pCsr->nSegment = 1;
|
| + pPending = 0;
|
| + }
|
| + }
|
| + }
|
| +
|
| + if( iLevel!=FTS3_SEGCURSOR_PENDING ){
|
| + if( rc==SQLITE_OK ){
|
| + rc = sqlite3Fts3AllSegdirs(p, iLevel, &pStmt);
|
| + }
|
| + while( rc==SQLITE_OK && SQLITE_ROW==(rc = sqlite3_step(pStmt)) ){
|
| +
|
| + /* Read the values returned by the SELECT into local variables. */
|
| + sqlite3_int64 iStartBlock = sqlite3_column_int64(pStmt, 1);
|
| + sqlite3_int64 iLeavesEndBlock = sqlite3_column_int64(pStmt, 2);
|
| + sqlite3_int64 iEndBlock = sqlite3_column_int64(pStmt, 3);
|
| + int nRoot = sqlite3_column_bytes(pStmt, 4);
|
| + char const *zRoot = sqlite3_column_blob(pStmt, 4);
|
| +
|
| + /* If nSegment is a multiple of 16 the array needs to be extended. */
|
| + if( (pCsr->nSegment%16)==0 ){
|
| + Fts3SegReader **apNew;
|
| + int nByte = (pCsr->nSegment + 16)*sizeof(Fts3SegReader*);
|
| + apNew = (Fts3SegReader **)sqlite3_realloc(pCsr->apSegment, nByte);
|
| + if( !apNew ){
|
| + rc = SQLITE_NOMEM;
|
| + goto finished;
|
| + }
|
| + pCsr->apSegment = apNew;
|
| + }
|
| +
|
| + /* If zTerm is not NULL, and this segment is not stored entirely on its
|
| + ** root node, the range of leaves scanned can be reduced. Do this. */
|
| + if( iStartBlock && zTerm ){
|
| + sqlite3_int64 *pi = (isPrefix ? &iLeavesEndBlock : 0);
|
| + rc = fts3SelectLeaf(p, zTerm, nTerm, zRoot, nRoot, &iStartBlock, pi);
|
| + if( rc!=SQLITE_OK ) goto finished;
|
| + if( isPrefix==0 && isScan==0 ) iLeavesEndBlock = iStartBlock;
|
| + }
|
| +
|
| + rc = sqlite3Fts3SegReaderNew(iAge, iStartBlock, iLeavesEndBlock,
|
| + iEndBlock, zRoot, nRoot, &pCsr->apSegment[pCsr->nSegment]
|
| + );
|
| + if( rc!=SQLITE_OK ) goto finished;
|
| + pCsr->nSegment++;
|
| + iAge++;
|
| + }
|
| + }
|
| +
|
| + finished:
|
| + rc2 = sqlite3_reset(pStmt);
|
| + if( rc==SQLITE_DONE ) rc = rc2;
|
| + sqlite3Fts3SegReaderFree(pPending);
|
| +
|
| + return rc;
|
| +}
|
| +
|
| +
|
| +static int fts3TermSegReaderCursor(
|
| + Fts3Cursor *pCsr, /* Virtual table cursor handle */
|
| + const char *zTerm, /* Term to query for */
|
| + int nTerm, /* Size of zTerm in bytes */
|
| + int isPrefix, /* True for a prefix search */
|
| + Fts3SegReaderCursor **ppSegcsr /* OUT: Allocated seg-reader cursor */
|
| +){
|
| + Fts3SegReaderCursor *pSegcsr; /* Object to allocate and return */
|
| + int rc = SQLITE_NOMEM; /* Return code */
|
| +
|
| + pSegcsr = sqlite3_malloc(sizeof(Fts3SegReaderCursor));
|
| + if( pSegcsr ){
|
| + Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
|
| + int i;
|
| + int nCost = 0;
|
| + rc = sqlite3Fts3SegReaderCursor(
|
| + p, FTS3_SEGCURSOR_ALL, zTerm, nTerm, isPrefix, 0, pSegcsr);
|
| +
|
| + for(i=0; rc==SQLITE_OK && i<pSegcsr->nSegment; i++){
|
| + rc = sqlite3Fts3SegReaderCost(pCsr, pSegcsr->apSegment[i], &nCost);
|
| + }
|
| + pSegcsr->nCost = nCost;
|
| + }
|
| +
|
| + *ppSegcsr = pSegcsr;
|
| + return rc;
|
| +}
|
| +
|
| +static void fts3SegReaderCursorFree(Fts3SegReaderCursor *pSegcsr){
|
| + sqlite3Fts3SegReaderFinish(pSegcsr);
|
| + sqlite3_free(pSegcsr);
|
| +}
|
| +
|
| +/*
|
| +** This function retreives the doclist for the specified term (or term
|
| +** prefix) from the database.
|
| +**
|
| +** The returned doclist may be in one of two formats, depending on the
|
| +** value of parameter isReqPos. If isReqPos is zero, then the doclist is
|
| +** a sorted list of delta-compressed docids (a bare doclist). If isReqPos
|
| +** is non-zero, then the returned list is in the same format as is stored
|
| +** in the database without the found length specifier at the start of on-disk
|
| +** doclists.
|
| +*/
|
| +static int fts3TermSelect(
|
| + Fts3Table *p, /* Virtual table handle */
|
| + Fts3PhraseToken *pTok, /* Token to query for */
|
| + int iColumn, /* Column to query (or -ve for all columns) */
|
| + int isReqPos, /* True to include position lists in output */
|
| + int *pnOut, /* OUT: Size of buffer at *ppOut */
|
| + char **ppOut /* OUT: Malloced result buffer */
|
| +){
|
| + int rc; /* Return code */
|
| + Fts3SegReaderCursor *pSegcsr; /* Seg-reader cursor for this term */
|
| + TermSelect tsc; /* Context object for fts3TermSelectCb() */
|
| + Fts3SegFilter filter; /* Segment term filter configuration */
|
| +
|
| + pSegcsr = pTok->pSegcsr;
|
| + memset(&tsc, 0, sizeof(TermSelect));
|
| + tsc.isReqPos = isReqPos;
|
| +
|
| + filter.flags = FTS3_SEGMENT_IGNORE_EMPTY
|
| + | (pTok->isPrefix ? FTS3_SEGMENT_PREFIX : 0)
|
| + | (isReqPos ? FTS3_SEGMENT_REQUIRE_POS : 0)
|
| + | (iColumn<p->nColumn ? FTS3_SEGMENT_COLUMN_FILTER : 0);
|
| + filter.iCol = iColumn;
|
| + filter.zTerm = pTok->z;
|
| + filter.nTerm = pTok->n;
|
| +
|
| + rc = sqlite3Fts3SegReaderStart(p, pSegcsr, &filter);
|
| + while( SQLITE_OK==rc
|
| + && SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, pSegcsr))
|
| + ){
|
| + rc = fts3TermSelectCb(p, (void *)&tsc,
|
| + pSegcsr->zTerm, pSegcsr->nTerm, pSegcsr->aDoclist, pSegcsr->nDoclist
|
| + );
|
| + }
|
| +
|
| + if( rc==SQLITE_OK ){
|
| + rc = fts3TermSelectMerge(&tsc);
|
| + }
|
| + if( rc==SQLITE_OK ){
|
| + *ppOut = tsc.aaOutput[0];
|
| + *pnOut = tsc.anOutput[0];
|
| + }else{
|
| + int i;
|
| + for(i=0; i<SizeofArray(tsc.aaOutput); i++){
|
| + sqlite3_free(tsc.aaOutput[i]);
|
| + }
|
| + }
|
| +
|
| + fts3SegReaderCursorFree(pSegcsr);
|
| + pTok->pSegcsr = 0;
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** This function counts the total number of docids in the doclist stored
|
| +** in buffer aList[], size nList bytes.
|
| +**
|
| +** If the isPoslist argument is true, then it is assumed that the doclist
|
| +** contains a position-list following each docid. Otherwise, it is assumed
|
| +** that the doclist is simply a list of docids stored as delta encoded
|
| +** varints.
|
| +*/
|
| +static int fts3DoclistCountDocids(int isPoslist, char *aList, int nList){
|
| + int nDoc = 0; /* Return value */
|
| + if( aList ){
|
| + char *aEnd = &aList[nList]; /* Pointer to one byte after EOF */
|
| + char *p = aList; /* Cursor */
|
| + if( !isPoslist ){
|
| + /* The number of docids in the list is the same as the number of
|
| + ** varints. In FTS3 a varint consists of a single byte with the 0x80
|
| + ** bit cleared and zero or more bytes with the 0x80 bit set. So to
|
| + ** count the varints in the buffer, just count the number of bytes
|
| + ** with the 0x80 bit clear. */
|
| + while( p<aEnd ) nDoc += (((*p++)&0x80)==0);
|
| + }else{
|
| + while( p<aEnd ){
|
| + nDoc++;
|
| + while( (*p++)&0x80 ); /* Skip docid varint */
|
| + fts3PoslistCopy(0, &p); /* Skip over position list */
|
| + }
|
| + }
|
| + }
|
| +
|
| + return nDoc;
|
| +}
|
| +
|
| +/*
|
| +** Call sqlite3Fts3DeferToken() for each token in the expression pExpr.
|
| +*/
|
| +static int fts3DeferExpression(Fts3Cursor *pCsr, Fts3Expr *pExpr){
|
| + int rc = SQLITE_OK;
|
| + if( pExpr ){
|
| + rc = fts3DeferExpression(pCsr, pExpr->pLeft);
|
| + if( rc==SQLITE_OK ){
|
| + rc = fts3DeferExpression(pCsr, pExpr->pRight);
|
| + }
|
| + if( pExpr->eType==FTSQUERY_PHRASE ){
|
| + int iCol = pExpr->pPhrase->iColumn;
|
| + int i;
|
| + for(i=0; rc==SQLITE_OK && i<pExpr->pPhrase->nToken; i++){
|
| + Fts3PhraseToken *pToken = &pExpr->pPhrase->aToken[i];
|
| + if( pToken->pDeferred==0 ){
|
| + rc = sqlite3Fts3DeferToken(pCsr, pToken, iCol);
|
| + }
|
| + }
|
| + }
|
| + }
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** This function removes the position information from a doclist. When
|
| +** called, buffer aList (size *pnList bytes) contains a doclist that includes
|
| +** position information. This function removes the position information so
|
| +** that aList contains only docids, and adjusts *pnList to reflect the new
|
| +** (possibly reduced) size of the doclist.
|
| +*/
|
| +static void fts3DoclistStripPositions(
|
| + char *aList, /* IN/OUT: Buffer containing doclist */
|
| + int *pnList /* IN/OUT: Size of doclist in bytes */
|
| +){
|
| + if( aList ){
|
| + char *aEnd = &aList[*pnList]; /* Pointer to one byte after EOF */
|
| + char *p = aList; /* Input cursor */
|
| + char *pOut = aList; /* Output cursor */
|
| +
|
| + while( p<aEnd ){
|
| + sqlite3_int64 delta;
|
| + p += sqlite3Fts3GetVarint(p, &delta);
|
| + fts3PoslistCopy(0, &p);
|
| + pOut += sqlite3Fts3PutVarint(pOut, delta);
|
| + }
|
| +
|
| + *pnList = (int)(pOut - aList);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Return a DocList corresponding to the phrase *pPhrase.
|
| +**
|
| +** If this function returns SQLITE_OK, but *pnOut is set to a negative value,
|
| +** then no tokens in the phrase were looked up in the full-text index. This
|
| +** is only possible when this function is called from within xFilter(). The
|
| +** caller should assume that all documents match the phrase. The actual
|
| +** filtering will take place in xNext().
|
| +*/
|
| +static int fts3PhraseSelect(
|
| + Fts3Cursor *pCsr, /* Virtual table cursor handle */
|
| + Fts3Phrase *pPhrase, /* Phrase to return a doclist for */
|
| + int isReqPos, /* True if output should contain positions */
|
| + char **paOut, /* OUT: Pointer to malloc'd result buffer */
|
| + int *pnOut /* OUT: Size of buffer at *paOut */
|
| +){
|
| + char *pOut = 0;
|
| + int nOut = 0;
|
| + int rc = SQLITE_OK;
|
| + int ii;
|
| + int iCol = pPhrase->iColumn;
|
| + int isTermPos = (pPhrase->nToken>1 || isReqPos);
|
| + Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
|
| + int isFirst = 1;
|
| +
|
| + int iPrevTok = 0;
|
| + int nDoc = 0;
|
| +
|
| + /* If this is an xFilter() evaluation, create a segment-reader for each
|
| + ** phrase token. Or, if this is an xNext() or snippet/offsets/matchinfo
|
| + ** evaluation, only create segment-readers if there are no Fts3DeferredToken
|
| + ** objects attached to the phrase-tokens.
|
| + */
|
| + for(ii=0; ii<pPhrase->nToken; ii++){
|
| + Fts3PhraseToken *pTok = &pPhrase->aToken[ii];
|
| + if( pTok->pSegcsr==0 ){
|
| + if( (pCsr->eEvalmode==FTS3_EVAL_FILTER)
|
| + || (pCsr->eEvalmode==FTS3_EVAL_NEXT && pCsr->pDeferred==0)
|
| + || (pCsr->eEvalmode==FTS3_EVAL_MATCHINFO && pTok->bFulltext)
|
| + ){
|
| + rc = fts3TermSegReaderCursor(
|
| + pCsr, pTok->z, pTok->n, pTok->isPrefix, &pTok->pSegcsr
|
| + );
|
| + if( rc!=SQLITE_OK ) return rc;
|
| + }
|
| + }
|
| + }
|
| +
|
| + for(ii=0; ii<pPhrase->nToken; ii++){
|
| + Fts3PhraseToken *pTok; /* Token to find doclist for */
|
| + int iTok = 0; /* The token being queried this iteration */
|
| + char *pList = 0; /* Pointer to token doclist */
|
| + int nList = 0; /* Size of buffer at pList */
|
| +
|
| + /* Select a token to process. If this is an xFilter() call, then tokens
|
| + ** are processed in order from least to most costly. Otherwise, tokens
|
| + ** are processed in the order in which they occur in the phrase.
|
| + */
|
| + if( pCsr->eEvalmode==FTS3_EVAL_MATCHINFO ){
|
| + assert( isReqPos );
|
| + iTok = ii;
|
| + pTok = &pPhrase->aToken[iTok];
|
| + if( pTok->bFulltext==0 ) continue;
|
| + }else if( pCsr->eEvalmode==FTS3_EVAL_NEXT || isReqPos ){
|
| + iTok = ii;
|
| + pTok = &pPhrase->aToken[iTok];
|
| + }else{
|
| + int nMinCost = 0x7FFFFFFF;
|
| + int jj;
|
| +
|
| + /* Find the remaining token with the lowest cost. */
|
| + for(jj=0; jj<pPhrase->nToken; jj++){
|
| + Fts3SegReaderCursor *pSegcsr = pPhrase->aToken[jj].pSegcsr;
|
| + if( pSegcsr && pSegcsr->nCost<nMinCost ){
|
| + iTok = jj;
|
| + nMinCost = pSegcsr->nCost;
|
| + }
|
| + }
|
| + pTok = &pPhrase->aToken[iTok];
|
| +
|
| + /* This branch is taken if it is determined that loading the doclist
|
| + ** for the next token would require more IO than loading all documents
|
| + ** currently identified by doclist pOut/nOut. No further doclists will
|
| + ** be loaded from the full-text index for this phrase.
|
| + */
|
| + if( nMinCost>nDoc && ii>0 ){
|
| + rc = fts3DeferExpression(pCsr, pCsr->pExpr);
|
| + break;
|
| + }
|
| + }
|
| +
|
| + if( pCsr->eEvalmode==FTS3_EVAL_NEXT && pTok->pDeferred ){
|
| + rc = fts3DeferredTermSelect(pTok->pDeferred, isTermPos, &nList, &pList);
|
| + }else{
|
| + if( pTok->pSegcsr ){
|
| + rc = fts3TermSelect(p, pTok, iCol, isTermPos, &nList, &pList);
|
| + }
|
| + pTok->bFulltext = 1;
|
| + }
|
| + assert( rc!=SQLITE_OK || pCsr->eEvalmode || pTok->pSegcsr==0 );
|
| + if( rc!=SQLITE_OK ) break;
|
| +
|
| + if( isFirst ){
|
| + pOut = pList;
|
| + nOut = nList;
|
| + if( pCsr->eEvalmode==FTS3_EVAL_FILTER && pPhrase->nToken>1 ){
|
| + nDoc = fts3DoclistCountDocids(1, pOut, nOut);
|
| + }
|
| + isFirst = 0;
|
| + iPrevTok = iTok;
|
| + }else{
|
| + /* Merge the new term list and the current output. */
|
| + char *aLeft, *aRight;
|
| + int nLeft, nRight;
|
| + int nDist;
|
| + int mt;
|
| +
|
| + /* If this is the final token of the phrase, and positions were not
|
| + ** requested by the caller, use MERGE_PHRASE instead of POS_PHRASE.
|
| + ** This drops the position information from the output list.
|
| + */
|
| + mt = MERGE_POS_PHRASE;
|
| + if( ii==pPhrase->nToken-1 && !isReqPos ) mt = MERGE_PHRASE;
|
| +
|
| + assert( iPrevTok!=iTok );
|
| + if( iPrevTok<iTok ){
|
| + aLeft = pOut;
|
| + nLeft = nOut;
|
| + aRight = pList;
|
| + nRight = nList;
|
| + nDist = iTok-iPrevTok;
|
| + iPrevTok = iTok;
|
| + }else{
|
| + aRight = pOut;
|
| + nRight = nOut;
|
| + aLeft = pList;
|
| + nLeft = nList;
|
| + nDist = iPrevTok-iTok;
|
| + }
|
| + pOut = aRight;
|
| + fts3DoclistMerge(
|
| + mt, nDist, 0, pOut, &nOut, aLeft, nLeft, aRight, nRight, &nDoc
|
| + );
|
| + sqlite3_free(aLeft);
|
| + }
|
| + assert( nOut==0 || pOut!=0 );
|
| + }
|
| +
|
| + if( rc==SQLITE_OK ){
|
| + if( ii!=pPhrase->nToken ){
|
| + assert( pCsr->eEvalmode==FTS3_EVAL_FILTER && isReqPos==0 );
|
| + fts3DoclistStripPositions(pOut, &nOut);
|
| + }
|
| + *paOut = pOut;
|
| + *pnOut = nOut;
|
| + }else{
|
| + sqlite3_free(pOut);
|
| + }
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** This function merges two doclists according to the requirements of a
|
| +** NEAR operator.
|
| +**
|
| +** Both input doclists must include position information. The output doclist
|
| +** includes position information if the first argument to this function
|
| +** is MERGE_POS_NEAR, or does not if it is MERGE_NEAR.
|
| +*/
|
| +static int fts3NearMerge(
|
| + int mergetype, /* MERGE_POS_NEAR or MERGE_NEAR */
|
| + int nNear, /* Parameter to NEAR operator */
|
| + int nTokenLeft, /* Number of tokens in LHS phrase arg */
|
| + char *aLeft, /* Doclist for LHS (incl. positions) */
|
| + int nLeft, /* Size of LHS doclist in bytes */
|
| + int nTokenRight, /* As nTokenLeft */
|
| + char *aRight, /* As aLeft */
|
| + int nRight, /* As nRight */
|
| + char **paOut, /* OUT: Results of merge (malloced) */
|
| + int *pnOut /* OUT: Sized of output buffer */
|
| +){
|
| + char *aOut; /* Buffer to write output doclist to */
|
| + int rc; /* Return code */
|
| +
|
| + assert( mergetype==MERGE_POS_NEAR || MERGE_NEAR );
|
| +
|
| + aOut = sqlite3_malloc(nLeft+nRight+1);
|
| + if( aOut==0 ){
|
| + rc = SQLITE_NOMEM;
|
| + }else{
|
| + rc = fts3DoclistMerge(mergetype, nNear+nTokenRight, nNear+nTokenLeft,
|
| + aOut, pnOut, aLeft, nLeft, aRight, nRight, 0
|
| + );
|
| + if( rc!=SQLITE_OK ){
|
| + sqlite3_free(aOut);
|
| + aOut = 0;
|
| + }
|
| + }
|
| +
|
| + *paOut = aOut;
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** This function is used as part of the processing for the snippet() and
|
| +** offsets() functions.
|
| +**
|
| +** Both pLeft and pRight are expression nodes of type FTSQUERY_PHRASE. Both
|
| +** have their respective doclists (including position information) loaded
|
| +** in Fts3Expr.aDoclist/nDoclist. This function removes all entries from
|
| +** each doclist that are not within nNear tokens of a corresponding entry
|
| +** in the other doclist.
|
| +*/
|
| +int sqlite3Fts3ExprNearTrim(Fts3Expr *pLeft, Fts3Expr *pRight, int nNear){
|
| + int rc; /* Return code */
|
| +
|
| + assert( pLeft->eType==FTSQUERY_PHRASE );
|
| + assert( pRight->eType==FTSQUERY_PHRASE );
|
| + assert( pLeft->isLoaded && pRight->isLoaded );
|
| +
|
| + if( pLeft->aDoclist==0 || pRight->aDoclist==0 ){
|
| + sqlite3_free(pLeft->aDoclist);
|
| + sqlite3_free(pRight->aDoclist);
|
| + pRight->aDoclist = 0;
|
| + pLeft->aDoclist = 0;
|
| + rc = SQLITE_OK;
|
| + }else{
|
| + char *aOut; /* Buffer in which to assemble new doclist */
|
| + int nOut; /* Size of buffer aOut in bytes */
|
| +
|
| + rc = fts3NearMerge(MERGE_POS_NEAR, nNear,
|
| + pLeft->pPhrase->nToken, pLeft->aDoclist, pLeft->nDoclist,
|
| + pRight->pPhrase->nToken, pRight->aDoclist, pRight->nDoclist,
|
| + &aOut, &nOut
|
| + );
|
| + if( rc!=SQLITE_OK ) return rc;
|
| + sqlite3_free(pRight->aDoclist);
|
| + pRight->aDoclist = aOut;
|
| + pRight->nDoclist = nOut;
|
| +
|
| + rc = fts3NearMerge(MERGE_POS_NEAR, nNear,
|
| + pRight->pPhrase->nToken, pRight->aDoclist, pRight->nDoclist,
|
| + pLeft->pPhrase->nToken, pLeft->aDoclist, pLeft->nDoclist,
|
| + &aOut, &nOut
|
| + );
|
| + sqlite3_free(pLeft->aDoclist);
|
| + pLeft->aDoclist = aOut;
|
| + pLeft->nDoclist = nOut;
|
| + }
|
| + return rc;
|
| +}
|
| +
|
| +
|
| +/*
|
| +** Allocate an Fts3SegReaderArray for each token in the expression pExpr.
|
| +** The allocated objects are stored in the Fts3PhraseToken.pArray member
|
| +** variables of each token structure.
|
| +*/
|
| +static int fts3ExprAllocateSegReaders(
|
| + Fts3Cursor *pCsr, /* FTS3 table */
|
| + Fts3Expr *pExpr, /* Expression to create seg-readers for */
|
| + int *pnExpr /* OUT: Number of AND'd expressions */
|
| +){
|
| + int rc = SQLITE_OK; /* Return code */
|
| +
|
| + assert( pCsr->eEvalmode==FTS3_EVAL_FILTER );
|
| + if( pnExpr && pExpr->eType!=FTSQUERY_AND ){
|
| + (*pnExpr)++;
|
| + pnExpr = 0;
|
| + }
|
| +
|
| + if( pExpr->eType==FTSQUERY_PHRASE ){
|
| + Fts3Phrase *pPhrase = pExpr->pPhrase;
|
| + int ii;
|
| +
|
| + for(ii=0; rc==SQLITE_OK && ii<pPhrase->nToken; ii++){
|
| + Fts3PhraseToken *pTok = &pPhrase->aToken[ii];
|
| + if( pTok->pSegcsr==0 ){
|
| + rc = fts3TermSegReaderCursor(
|
| + pCsr, pTok->z, pTok->n, pTok->isPrefix, &pTok->pSegcsr
|
| + );
|
| + }
|
| + }
|
| + }else{
|
| + rc = fts3ExprAllocateSegReaders(pCsr, pExpr->pLeft, pnExpr);
|
| + if( rc==SQLITE_OK ){
|
| + rc = fts3ExprAllocateSegReaders(pCsr, pExpr->pRight, pnExpr);
|
| + }
|
| + }
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** Free the Fts3SegReaderArray objects associated with each token in the
|
| +** expression pExpr. In other words, this function frees the resources
|
| +** allocated by fts3ExprAllocateSegReaders().
|
| +*/
|
| +static void fts3ExprFreeSegReaders(Fts3Expr *pExpr){
|
| + if( pExpr ){
|
| + Fts3Phrase *pPhrase = pExpr->pPhrase;
|
| + if( pPhrase ){
|
| + int kk;
|
| + for(kk=0; kk<pPhrase->nToken; kk++){
|
| + fts3SegReaderCursorFree(pPhrase->aToken[kk].pSegcsr);
|
| + pPhrase->aToken[kk].pSegcsr = 0;
|
| + }
|
| + }
|
| + fts3ExprFreeSegReaders(pExpr->pLeft);
|
| + fts3ExprFreeSegReaders(pExpr->pRight);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Return the sum of the costs of all tokens in the expression pExpr. This
|
| +** function must be called after Fts3SegReaderArrays have been allocated
|
| +** for all tokens using fts3ExprAllocateSegReaders().
|
| +*/
|
| +static int fts3ExprCost(Fts3Expr *pExpr){
|
| + int nCost; /* Return value */
|
| + if( pExpr->eType==FTSQUERY_PHRASE ){
|
| + Fts3Phrase *pPhrase = pExpr->pPhrase;
|
| + int ii;
|
| + nCost = 0;
|
| + for(ii=0; ii<pPhrase->nToken; ii++){
|
| + Fts3SegReaderCursor *pSegcsr = pPhrase->aToken[ii].pSegcsr;
|
| + if( pSegcsr ) nCost += pSegcsr->nCost;
|
| + }
|
| + }else{
|
| + nCost = fts3ExprCost(pExpr->pLeft) + fts3ExprCost(pExpr->pRight);
|
| + }
|
| + return nCost;
|
| +}
|
| +
|
| +/*
|
| +** The following is a helper function (and type) for fts3EvalExpr(). It
|
| +** must be called after Fts3SegReaders have been allocated for every token
|
| +** in the expression. See the context it is called from in fts3EvalExpr()
|
| +** for further explanation.
|
| +*/
|
| +typedef struct ExprAndCost ExprAndCost;
|
| +struct ExprAndCost {
|
| + Fts3Expr *pExpr;
|
| + int nCost;
|
| +};
|
| +static void fts3ExprAssignCosts(
|
| + Fts3Expr *pExpr, /* Expression to create seg-readers for */
|
| + ExprAndCost **ppExprCost /* OUT: Write to *ppExprCost */
|
| +){
|
| + if( pExpr->eType==FTSQUERY_AND ){
|
| + fts3ExprAssignCosts(pExpr->pLeft, ppExprCost);
|
| + fts3ExprAssignCosts(pExpr->pRight, ppExprCost);
|
| + }else{
|
| + (*ppExprCost)->pExpr = pExpr;
|
| + (*ppExprCost)->nCost = fts3ExprCost(pExpr);
|
| + (*ppExprCost)++;
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Evaluate the full-text expression pExpr against FTS3 table pTab. Store
|
| +** the resulting doclist in *paOut and *pnOut. This routine mallocs for
|
| +** the space needed to store the output. The caller is responsible for
|
| +** freeing the space when it has finished.
|
| +**
|
| +** This function is called in two distinct contexts:
|
| +**
|
| +** * From within the virtual table xFilter() method. In this case, the
|
| +** output doclist contains entries for all rows in the table, based on
|
| +** data read from the full-text index.
|
| +**
|
| +** In this case, if the query expression contains one or more tokens that
|
| +** are very common, then the returned doclist may contain a superset of
|
| +** the documents that actually match the expression.
|
| +**
|
| +** * From within the virtual table xNext() method. This call is only made
|
| +** if the call from within xFilter() found that there were very common
|
| +** tokens in the query expression and did return a superset of the
|
| +** matching documents. In this case the returned doclist contains only
|
| +** entries that correspond to the current row of the table. Instead of
|
| +** reading the data for each token from the full-text index, the data is
|
| +** already available in-memory in the Fts3PhraseToken.pDeferred structures.
|
| +** See fts3EvalDeferred() for how it gets there.
|
| +**
|
| +** In the first case above, Fts3Cursor.doDeferred==0. In the second (if it is
|
| +** required) Fts3Cursor.doDeferred==1.
|
| +**
|
| +** If the SQLite invokes the snippet(), offsets() or matchinfo() function
|
| +** as part of a SELECT on an FTS3 table, this function is called on each
|
| +** individual phrase expression in the query. If there were very common tokens
|
| +** found in the xFilter() call, then this function is called once for phrase
|
| +** for each row visited, and the returned doclist contains entries for the
|
| +** current row only. Otherwise, if there were no very common tokens, then this
|
| +** function is called once only for each phrase in the query and the returned
|
| +** doclist contains entries for all rows of the table.
|
| +**
|
| +** Fts3Cursor.doDeferred==1 when this function is called on phrases as a
|
| +** result of a snippet(), offsets() or matchinfo() invocation.
|
| +*/
|
| +static int fts3EvalExpr(
|
| + Fts3Cursor *p, /* Virtual table cursor handle */
|
| + Fts3Expr *pExpr, /* Parsed fts3 expression */
|
| + char **paOut, /* OUT: Pointer to malloc'd result buffer */
|
| + int *pnOut, /* OUT: Size of buffer at *paOut */
|
| + int isReqPos /* Require positions in output buffer */
|
| +){
|
| + int rc = SQLITE_OK; /* Return code */
|
| +
|
| + /* Zero the output parameters. */
|
| + *paOut = 0;
|
| + *pnOut = 0;
|
| +
|
| + if( pExpr ){
|
| + assert( pExpr->eType==FTSQUERY_NEAR || pExpr->eType==FTSQUERY_OR
|
| + || pExpr->eType==FTSQUERY_AND || pExpr->eType==FTSQUERY_NOT
|
| + || pExpr->eType==FTSQUERY_PHRASE
|
| + );
|
| + assert( pExpr->eType==FTSQUERY_PHRASE || isReqPos==0 );
|
| +
|
| + if( pExpr->eType==FTSQUERY_PHRASE ){
|
| + rc = fts3PhraseSelect(p, pExpr->pPhrase,
|
| + isReqPos || (pExpr->pParent && pExpr->pParent->eType==FTSQUERY_NEAR),
|
| + paOut, pnOut
|
| + );
|
| + fts3ExprFreeSegReaders(pExpr);
|
| + }else if( p->eEvalmode==FTS3_EVAL_FILTER && pExpr->eType==FTSQUERY_AND ){
|
| + ExprAndCost *aExpr = 0; /* Array of AND'd expressions and costs */
|
| + int nExpr = 0; /* Size of aExpr[] */
|
| + char *aRet = 0; /* Doclist to return to caller */
|
| + int nRet = 0; /* Length of aRet[] in bytes */
|
| + int nDoc = 0x7FFFFFFF;
|
| +
|
| + assert( !isReqPos );
|
| +
|
| + rc = fts3ExprAllocateSegReaders(p, pExpr, &nExpr);
|
| + if( rc==SQLITE_OK ){
|
| + assert( nExpr>1 );
|
| + aExpr = sqlite3_malloc(sizeof(ExprAndCost) * nExpr);
|
| + if( !aExpr ) rc = SQLITE_NOMEM;
|
| + }
|
| + if( rc==SQLITE_OK ){
|
| + int ii; /* Used to iterate through expressions */
|
| +
|
| + fts3ExprAssignCosts(pExpr, &aExpr);
|
| + aExpr -= nExpr;
|
| + for(ii=0; ii<nExpr; ii++){
|
| + char *aNew;
|
| + int nNew;
|
| + int jj;
|
| + ExprAndCost *pBest = 0;
|
| +
|
| + for(jj=0; jj<nExpr; jj++){
|
| + ExprAndCost *pCand = &aExpr[jj];
|
| + if( pCand->pExpr && (pBest==0 || pCand->nCost<pBest->nCost) ){
|
| + pBest = pCand;
|
| + }
|
| + }
|
| +
|
| + if( pBest->nCost>nDoc ){
|
| + rc = fts3DeferExpression(p, p->pExpr);
|
| + break;
|
| + }else{
|
| + rc = fts3EvalExpr(p, pBest->pExpr, &aNew, &nNew, 0);
|
| + if( rc!=SQLITE_OK ) break;
|
| + pBest->pExpr = 0;
|
| + if( ii==0 ){
|
| + aRet = aNew;
|
| + nRet = nNew;
|
| + nDoc = fts3DoclistCountDocids(0, aRet, nRet);
|
| + }else{
|
| + fts3DoclistMerge(
|
| + MERGE_AND, 0, 0, aRet, &nRet, aRet, nRet, aNew, nNew, &nDoc
|
| + );
|
| + sqlite3_free(aNew);
|
| + }
|
| + }
|
| + }
|
| + }
|
| +
|
| + if( rc==SQLITE_OK ){
|
| + *paOut = aRet;
|
| + *pnOut = nRet;
|
| + }else{
|
| + assert( *paOut==0 );
|
| + sqlite3_free(aRet);
|
| + }
|
| + sqlite3_free(aExpr);
|
| + fts3ExprFreeSegReaders(pExpr);
|
| +
|
| + }else{
|
| + char *aLeft;
|
| + char *aRight;
|
| + int nLeft;
|
| + int nRight;
|
| +
|
| + assert( pExpr->eType==FTSQUERY_NEAR
|
| + || pExpr->eType==FTSQUERY_OR
|
| + || pExpr->eType==FTSQUERY_NOT
|
| + || (pExpr->eType==FTSQUERY_AND && p->eEvalmode==FTS3_EVAL_NEXT)
|
| + );
|
| +
|
| + if( 0==(rc = fts3EvalExpr(p, pExpr->pRight, &aRight, &nRight, isReqPos))
|
| + && 0==(rc = fts3EvalExpr(p, pExpr->pLeft, &aLeft, &nLeft, isReqPos))
|
| + ){
|
| + switch( pExpr->eType ){
|
| + case FTSQUERY_NEAR: {
|
| + Fts3Expr *pLeft;
|
| + Fts3Expr *pRight;
|
| + int mergetype = MERGE_NEAR;
|
| + if( pExpr->pParent && pExpr->pParent->eType==FTSQUERY_NEAR ){
|
| + mergetype = MERGE_POS_NEAR;
|
| + }
|
| + pLeft = pExpr->pLeft;
|
| + while( pLeft->eType==FTSQUERY_NEAR ){
|
| + pLeft=pLeft->pRight;
|
| + }
|
| + pRight = pExpr->pRight;
|
| + assert( pRight->eType==FTSQUERY_PHRASE );
|
| + assert( pLeft->eType==FTSQUERY_PHRASE );
|
| +
|
| + rc = fts3NearMerge(mergetype, pExpr->nNear,
|
| + pLeft->pPhrase->nToken, aLeft, nLeft,
|
| + pRight->pPhrase->nToken, aRight, nRight,
|
| + paOut, pnOut
|
| + );
|
| + sqlite3_free(aLeft);
|
| + break;
|
| + }
|
| +
|
| + case FTSQUERY_OR: {
|
| + /* Allocate a buffer for the output. The maximum size is the
|
| + ** sum of the sizes of the two input buffers. The +1 term is
|
| + ** so that a buffer of zero bytes is never allocated - this can
|
| + ** cause fts3DoclistMerge() to incorrectly return SQLITE_NOMEM.
|
| + */
|
| + char *aBuffer = sqlite3_malloc(nRight+nLeft+1);
|
| + rc = fts3DoclistMerge(MERGE_OR, 0, 0, aBuffer, pnOut,
|
| + aLeft, nLeft, aRight, nRight, 0
|
| + );
|
| + *paOut = aBuffer;
|
| + sqlite3_free(aLeft);
|
| + break;
|
| + }
|
| +
|
| + default: {
|
| + assert( FTSQUERY_NOT==MERGE_NOT && FTSQUERY_AND==MERGE_AND );
|
| + fts3DoclistMerge(pExpr->eType, 0, 0, aLeft, pnOut,
|
| + aLeft, nLeft, aRight, nRight, 0
|
| + );
|
| + *paOut = aLeft;
|
| + break;
|
| + }
|
| + }
|
| + }
|
| + sqlite3_free(aRight);
|
| + }
|
| + }
|
| +
|
| + assert( rc==SQLITE_OK || *paOut==0 );
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** This function is called from within xNext() for each row visited by
|
| +** an FTS3 query. If evaluating the FTS3 query expression within xFilter()
|
| +** was able to determine the exact set of matching rows, this function sets
|
| +** *pbRes to true and returns SQLITE_IO immediately.
|
| +**
|
| +** Otherwise, if evaluating the query expression within xFilter() returned a
|
| +** superset of the matching documents instead of an exact set (this happens
|
| +** when the query includes very common tokens and it is deemed too expensive to
|
| +** load their doclists from disk), this function tests if the current row
|
| +** really does match the FTS3 query.
|
| +**
|
| +** If an error occurs, an SQLite error code is returned. Otherwise, SQLITE_OK
|
| +** is returned and *pbRes is set to true if the current row matches the
|
| +** FTS3 query (and should be included in the results returned to SQLite), or
|
| +** false otherwise.
|
| +*/
|
| +static int fts3EvalDeferred(
|
| + Fts3Cursor *pCsr, /* FTS3 cursor pointing at row to test */
|
| + int *pbRes /* OUT: Set to true if row is a match */
|
| +){
|
| + int rc = SQLITE_OK;
|
| + if( pCsr->pDeferred==0 ){
|
| + *pbRes = 1;
|
| + }else{
|
| + rc = fts3CursorSeek(0, pCsr);
|
| + if( rc==SQLITE_OK ){
|
| + sqlite3Fts3FreeDeferredDoclists(pCsr);
|
| + rc = sqlite3Fts3CacheDeferredDoclists(pCsr);
|
| + }
|
| + if( rc==SQLITE_OK ){
|
| + char *a = 0;
|
| + int n = 0;
|
| + rc = fts3EvalExpr(pCsr, pCsr->pExpr, &a, &n, 0);
|
| + assert( n>=0 );
|
| + *pbRes = (n>0);
|
| + sqlite3_free(a);
|
| + }
|
| + }
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** Advance the cursor to the next row in the %_content table that
|
| +** matches the search criteria. For a MATCH search, this will be
|
| +** the next row that matches. For a full-table scan, this will be
|
| +** simply the next row in the %_content table. For a docid lookup,
|
| +** this routine simply sets the EOF flag.
|
| +**
|
| +** Return SQLITE_OK if nothing goes wrong. SQLITE_OK is returned
|
| +** even if we reach end-of-file. The fts3EofMethod() will be called
|
| +** subsequently to determine whether or not an EOF was hit.
|
| +*/
|
| +static int fts3NextMethod(sqlite3_vtab_cursor *pCursor){
|
| + int res;
|
| + int rc = SQLITE_OK; /* Return code */
|
| + Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
|
| +
|
| + pCsr->eEvalmode = FTS3_EVAL_NEXT;
|
| + do {
|
| + if( pCsr->aDoclist==0 ){
|
| + if( SQLITE_ROW!=sqlite3_step(pCsr->pStmt) ){
|
| + pCsr->isEof = 1;
|
| + rc = sqlite3_reset(pCsr->pStmt);
|
| + break;
|
| + }
|
| + pCsr->iPrevId = sqlite3_column_int64(pCsr->pStmt, 0);
|
| + }else{
|
| + if( pCsr->pNextId>=&pCsr->aDoclist[pCsr->nDoclist] ){
|
| + pCsr->isEof = 1;
|
| + break;
|
| + }
|
| + sqlite3_reset(pCsr->pStmt);
|
| + fts3GetDeltaVarint(&pCsr->pNextId, &pCsr->iPrevId);
|
| + pCsr->isRequireSeek = 1;
|
| + pCsr->isMatchinfoNeeded = 1;
|
| + }
|
| + }while( SQLITE_OK==(rc = fts3EvalDeferred(pCsr, &res)) && res==0 );
|
| +
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** This is the xFilter interface for the virtual table. See
|
| +** the virtual table xFilter method documentation for additional
|
| +** information.
|
| +**
|
| +** If idxNum==FTS3_FULLSCAN_SEARCH then do a full table scan against
|
| +** the %_content table.
|
| +**
|
| +** If idxNum==FTS3_DOCID_SEARCH then do a docid lookup for a single entry
|
| +** in the %_content table.
|
| +**
|
| +** If idxNum>=FTS3_FULLTEXT_SEARCH then use the full text index. The
|
| +** column on the left-hand side of the MATCH operator is column
|
| +** number idxNum-FTS3_FULLTEXT_SEARCH, 0 indexed. argv[0] is the right-hand
|
| +** side of the MATCH operator.
|
| +*/
|
| +static int fts3FilterMethod(
|
| + sqlite3_vtab_cursor *pCursor, /* The cursor used for this query */
|
| + int idxNum, /* Strategy index */
|
| + const char *idxStr, /* Unused */
|
| + int nVal, /* Number of elements in apVal */
|
| + sqlite3_value **apVal /* Arguments for the indexing scheme */
|
| +){
|
| + const char *azSql[] = {
|
| + "SELECT %s FROM %Q.'%q_content' AS x WHERE docid = ?", /* non-full-scan */
|
| + "SELECT %s FROM %Q.'%q_content' AS x ", /* full-scan */
|
| + };
|
| + int rc; /* Return code */
|
| + char *zSql; /* SQL statement used to access %_content */
|
| + Fts3Table *p = (Fts3Table *)pCursor->pVtab;
|
| + Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
|
| +
|
| + UNUSED_PARAMETER(idxStr);
|
| + UNUSED_PARAMETER(nVal);
|
| +
|
| + assert( idxNum>=0 && idxNum<=(FTS3_FULLTEXT_SEARCH+p->nColumn) );
|
| + assert( nVal==0 || nVal==1 );
|
| + assert( (nVal==0)==(idxNum==FTS3_FULLSCAN_SEARCH) );
|
| + assert( p->pSegments==0 );
|
| +
|
| + /* In case the cursor has been used before, clear it now. */
|
| + sqlite3_finalize(pCsr->pStmt);
|
| + sqlite3_free(pCsr->aDoclist);
|
| + sqlite3Fts3ExprFree(pCsr->pExpr);
|
| + memset(&pCursor[1], 0, sizeof(Fts3Cursor)-sizeof(sqlite3_vtab_cursor));
|
| +
|
| + if( idxNum!=FTS3_DOCID_SEARCH && idxNum!=FTS3_FULLSCAN_SEARCH ){
|
| + int iCol = idxNum-FTS3_FULLTEXT_SEARCH;
|
| + const char *zQuery = (const char *)sqlite3_value_text(apVal[0]);
|
| +
|
| + if( zQuery==0 && sqlite3_value_type(apVal[0])!=SQLITE_NULL ){
|
| + return SQLITE_NOMEM;
|
| + }
|
| +
|
| + rc = sqlite3Fts3ExprParse(p->pTokenizer, p->azColumn, p->nColumn,
|
| + iCol, zQuery, -1, &pCsr->pExpr
|
| + );
|
| + if( rc!=SQLITE_OK ){
|
| + if( rc==SQLITE_ERROR ){
|
| + p->base.zErrMsg = sqlite3_mprintf("malformed MATCH expression: [%s]",
|
| + zQuery);
|
| + }
|
| + return rc;
|
| + }
|
| +
|
| + rc = sqlite3Fts3ReadLock(p);
|
| + if( rc!=SQLITE_OK ) return rc;
|
| +
|
| + rc = fts3EvalExpr(pCsr, pCsr->pExpr, &pCsr->aDoclist, &pCsr->nDoclist, 0);
|
| + sqlite3Fts3SegmentsClose(p);
|
| + if( rc!=SQLITE_OK ) return rc;
|
| + pCsr->pNextId = pCsr->aDoclist;
|
| + pCsr->iPrevId = 0;
|
| + }
|
| +
|
| + /* Compile a SELECT statement for this cursor. For a full-table-scan, the
|
| + ** statement loops through all rows of the %_content table. For a
|
| + ** full-text query or docid lookup, the statement retrieves a single
|
| + ** row by docid.
|
| + */
|
| + zSql = (char *)azSql[idxNum==FTS3_FULLSCAN_SEARCH];
|
| + zSql = sqlite3_mprintf(zSql, p->zReadExprlist, p->zDb, p->zName);
|
| + if( !zSql ){
|
| + rc = SQLITE_NOMEM;
|
| + }else{
|
| + rc = sqlite3_prepare_v2(p->db, zSql, -1, &pCsr->pStmt, 0);
|
| + sqlite3_free(zSql);
|
| + }
|
| + if( rc==SQLITE_OK && idxNum==FTS3_DOCID_SEARCH ){
|
| + rc = sqlite3_bind_value(pCsr->pStmt, 1, apVal[0]);
|
| + }
|
| + pCsr->eSearch = (i16)idxNum;
|
| +
|
| + if( rc!=SQLITE_OK ) return rc;
|
| + return fts3NextMethod(pCursor);
|
| +}
|
| +
|
| +/*
|
| +** This is the xEof method of the virtual table. SQLite calls this
|
| +** routine to find out if it has reached the end of a result set.
|
| +*/
|
| +static int fts3EofMethod(sqlite3_vtab_cursor *pCursor){
|
| + return ((Fts3Cursor *)pCursor)->isEof;
|
| +}
|
| +
|
| +/*
|
| +** This is the xRowid method. The SQLite core calls this routine to
|
| +** retrieve the rowid for the current row of the result set. fts3
|
| +** exposes %_content.docid as the rowid for the virtual table. The
|
| +** rowid should be written to *pRowid.
|
| +*/
|
| +static int fts3RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
|
| + Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;
|
| + if( pCsr->aDoclist ){
|
| + *pRowid = pCsr->iPrevId;
|
| + }else{
|
| + /* This branch runs if the query is implemented using a full-table scan
|
| + ** (not using the full-text index). In this case grab the rowid from the
|
| + ** SELECT statement.
|
| + */
|
| + assert( pCsr->isRequireSeek==0 );
|
| + *pRowid = sqlite3_column_int64(pCsr->pStmt, 0);
|
| + }
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** This is the xColumn method, called by SQLite to request a value from
|
| +** the row that the supplied cursor currently points to.
|
| +*/
|
| +static int fts3ColumnMethod(
|
| + sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
|
| + sqlite3_context *pContext, /* Context for sqlite3_result_xxx() calls */
|
| + int iCol /* Index of column to read value from */
|
| +){
|
| + int rc; /* Return Code */
|
| + Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;
|
| + Fts3Table *p = (Fts3Table *)pCursor->pVtab;
|
| +
|
| + /* The column value supplied by SQLite must be in range. */
|
| + assert( iCol>=0 && iCol<=p->nColumn+1 );
|
| +
|
| + if( iCol==p->nColumn+1 ){
|
| + /* This call is a request for the "docid" column. Since "docid" is an
|
| + ** alias for "rowid", use the xRowid() method to obtain the value.
|
| + */
|
| + sqlite3_int64 iRowid;
|
| + rc = fts3RowidMethod(pCursor, &iRowid);
|
| + sqlite3_result_int64(pContext, iRowid);
|
| + }else if( iCol==p->nColumn ){
|
| + /* The extra column whose name is the same as the table.
|
| + ** Return a blob which is a pointer to the cursor.
|
| + */
|
| + sqlite3_result_blob(pContext, &pCsr, sizeof(pCsr), SQLITE_TRANSIENT);
|
| + rc = SQLITE_OK;
|
| + }else{
|
| + rc = fts3CursorSeek(0, pCsr);
|
| + if( rc==SQLITE_OK ){
|
| + sqlite3_result_value(pContext, sqlite3_column_value(pCsr->pStmt, iCol+1));
|
| + }
|
| + }
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** This function is the implementation of the xUpdate callback used by
|
| +** FTS3 virtual tables. It is invoked by SQLite each time a row is to be
|
| +** inserted, updated or deleted.
|
| +*/
|
| +static int fts3UpdateMethod(
|
| + sqlite3_vtab *pVtab, /* Virtual table handle */
|
| + int nArg, /* Size of argument array */
|
| + sqlite3_value **apVal, /* Array of arguments */
|
| + sqlite_int64 *pRowid /* OUT: The affected (or effected) rowid */
|
| +){
|
| + return sqlite3Fts3UpdateMethod(pVtab, nArg, apVal, pRowid);
|
| +}
|
| +
|
| +/*
|
| +** Implementation of xSync() method. Flush the contents of the pending-terms
|
| +** hash-table to the database.
|
| +*/
|
| +static int fts3SyncMethod(sqlite3_vtab *pVtab){
|
| + int rc = sqlite3Fts3PendingTermsFlush((Fts3Table *)pVtab);
|
| + sqlite3Fts3SegmentsClose((Fts3Table *)pVtab);
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** Implementation of xBegin() method. This is a no-op.
|
| +*/
|
| +static int fts3BeginMethod(sqlite3_vtab *pVtab){
|
| + UNUSED_PARAMETER(pVtab);
|
| + assert( ((Fts3Table *)pVtab)->nPendingData==0 );
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** Implementation of xCommit() method. This is a no-op. The contents of
|
| +** the pending-terms hash-table have already been flushed into the database
|
| +** by fts3SyncMethod().
|
| +*/
|
| +static int fts3CommitMethod(sqlite3_vtab *pVtab){
|
| + UNUSED_PARAMETER(pVtab);
|
| + assert( ((Fts3Table *)pVtab)->nPendingData==0 );
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** Implementation of xRollback(). Discard the contents of the pending-terms
|
| +** hash-table. Any changes made to the database are reverted by SQLite.
|
| +*/
|
| +static int fts3RollbackMethod(sqlite3_vtab *pVtab){
|
| + sqlite3Fts3PendingTermsClear((Fts3Table *)pVtab);
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** Load the doclist associated with expression pExpr to pExpr->aDoclist.
|
| +** The loaded doclist contains positions as well as the document ids.
|
| +** This is used by the matchinfo(), snippet() and offsets() auxillary
|
| +** functions.
|
| +*/
|
| +int sqlite3Fts3ExprLoadDoclist(Fts3Cursor *pCsr, Fts3Expr *pExpr){
|
| + int rc;
|
| + assert( pExpr->eType==FTSQUERY_PHRASE && pExpr->pPhrase );
|
| + assert( pCsr->eEvalmode==FTS3_EVAL_NEXT );
|
| + rc = fts3EvalExpr(pCsr, pExpr, &pExpr->aDoclist, &pExpr->nDoclist, 1);
|
| + return rc;
|
| +}
|
| +
|
| +int sqlite3Fts3ExprLoadFtDoclist(
|
| + Fts3Cursor *pCsr,
|
| + Fts3Expr *pExpr,
|
| + char **paDoclist,
|
| + int *pnDoclist
|
| +){
|
| + int rc;
|
| + assert( pCsr->eEvalmode==FTS3_EVAL_NEXT );
|
| + assert( pExpr->eType==FTSQUERY_PHRASE && pExpr->pPhrase );
|
| + pCsr->eEvalmode = FTS3_EVAL_MATCHINFO;
|
| + rc = fts3EvalExpr(pCsr, pExpr, paDoclist, pnDoclist, 1);
|
| + pCsr->eEvalmode = FTS3_EVAL_NEXT;
|
| + return rc;
|
| +}
|
| +
|
| +/*
|
| +** After ExprLoadDoclist() (see above) has been called, this function is
|
| +** used to iterate/search through the position lists that make up the doclist
|
| +** stored in pExpr->aDoclist.
|
| +*/
|
| +char *sqlite3Fts3FindPositions(
|
| + Fts3Expr *pExpr, /* Access this expressions doclist */
|
| + sqlite3_int64 iDocid, /* Docid associated with requested pos-list */
|
| + int iCol /* Column of requested pos-list */
|
| +){
|
| + assert( pExpr->isLoaded );
|
| + if( pExpr->aDoclist ){
|
| + char *pEnd = &pExpr->aDoclist[pExpr->nDoclist];
|
| + char *pCsr;
|
| +
|
| + if( pExpr->pCurrent==0 ){
|
| + pExpr->pCurrent = pExpr->aDoclist;
|
| + pExpr->iCurrent = 0;
|
| + pExpr->pCurrent += sqlite3Fts3GetVarint(pExpr->pCurrent,&pExpr->iCurrent);
|
| + }
|
| + pCsr = pExpr->pCurrent;
|
| + assert( pCsr );
|
| +
|
| + while( pCsr<pEnd ){
|
| + if( pExpr->iCurrent<iDocid ){
|
| + fts3PoslistCopy(0, &pCsr);
|
| + if( pCsr<pEnd ){
|
| + fts3GetDeltaVarint(&pCsr, &pExpr->iCurrent);
|
| + }
|
| + pExpr->pCurrent = pCsr;
|
| + }else{
|
| + if( pExpr->iCurrent==iDocid ){
|
| + int iThis = 0;
|
| + if( iCol<0 ){
|
| + /* If iCol is negative, return a pointer to the start of the
|
| + ** position-list (instead of a pointer to the start of a list
|
| + ** of offsets associated with a specific column).
|
| + */
|
| + return pCsr;
|
| + }
|
| + while( iThis<iCol ){
|
| + fts3ColumnlistCopy(0, &pCsr);
|
| + if( *pCsr==0x00 ) return 0;
|
| + pCsr++;
|
| + pCsr += sqlite3Fts3GetVarint32(pCsr, &iThis);
|
| + }
|
| + if( iCol==iThis && (*pCsr&0xFE) ) return pCsr;
|
| + }
|
| + return 0;
|
| + }
|
| + }
|
| + }
|
| +
|
| + return 0;
|
| +}
|
| +
|
| +/*
|
| +** Helper function used by the implementation of the overloaded snippet(),
|
| +** offsets() and optimize() SQL functions.
|
| +**
|
| +** If the value passed as the third argument is a blob of size
|
| +** sizeof(Fts3Cursor*), then the blob contents are copied to the
|
| +** output variable *ppCsr and SQLITE_OK is returned. Otherwise, an error
|
| +** message is written to context pContext and SQLITE_ERROR returned. The
|
| +** string passed via zFunc is used as part of the error message.
|
| +*/
|
| +static int fts3FunctionArg(
|
| + sqlite3_context *pContext, /* SQL function call context */
|
| + const char *zFunc, /* Function name */
|
| + sqlite3_value *pVal, /* argv[0] passed to function */
|
| + Fts3Cursor **ppCsr /* OUT: Store cursor handle here */
|
| +){
|
| + Fts3Cursor *pRet;
|
| + if( sqlite3_value_type(pVal)!=SQLITE_BLOB
|
| + || sqlite3_value_bytes(pVal)!=sizeof(Fts3Cursor *)
|
| + ){
|
| + char *zErr = sqlite3_mprintf("illegal first argument to %s", zFunc);
|
| + sqlite3_result_error(pContext, zErr, -1);
|
| + sqlite3_free(zErr);
|
| + return SQLITE_ERROR;
|
| + }
|
| + memcpy(&pRet, sqlite3_value_blob(pVal), sizeof(Fts3Cursor *));
|
| + *ppCsr = pRet;
|
| + return SQLITE_OK;
|
| +}
|
| +
|
| +/*
|
| +** Implementation of the snippet() function for FTS3
|
| +*/
|
| +static void fts3SnippetFunc(
|
| + sqlite3_context *pContext, /* SQLite function call context */
|
| + int nVal, /* Size of apVal[] array */
|
| + sqlite3_value **apVal /* Array of arguments */
|
| +){
|
| + Fts3Cursor *pCsr; /* Cursor handle passed through apVal[0] */
|
| + const char *zStart = "<b>";
|
| + const char *zEnd = "</b>";
|
| + const char *zEllipsis = "<b>...</b>";
|
| + int iCol = -1;
|
| + int nToken = 15; /* Default number of tokens in snippet */
|
| +
|
| + /* There must be at least one argument passed to this function (otherwise
|
| + ** the non-overloaded version would have been called instead of this one).
|
| + */
|
| + assert( nVal>=1 );
|
| +
|
| + if( nVal>6 ){
|
| + sqlite3_result_error(pContext,
|
| + "wrong number of arguments to function snippet()", -1);
|
| + return;
|
| + }
|
| + if( fts3FunctionArg(pContext, "snippet", apVal[0], &pCsr) ) return;
|
| +
|
| + switch( nVal ){
|
| + case 6: nToken = sqlite3_value_int(apVal[5]);
|
| + case 5: iCol = sqlite3_value_int(apVal[4]);
|
| + case 4: zEllipsis = (const char*)sqlite3_value_text(apVal[3]);
|
| + case 3: zEnd = (const char*)sqlite3_value_text(apVal[2]);
|
| + case 2: zStart = (const char*)sqlite3_value_text(apVal[1]);
|
| + }
|
| + if( !zEllipsis || !zEnd || !zStart ){
|
| + sqlite3_result_error_nomem(pContext);
|
| + }else if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
|
| + sqlite3Fts3Snippet(pContext, pCsr, zStart, zEnd, zEllipsis, iCol, nToken);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Implementation of the offsets() function for FTS3
|
| +*/
|
| +static void fts3OffsetsFunc(
|
| + sqlite3_context *pContext, /* SQLite function call context */
|
| + int nVal, /* Size of argument array */
|
| + sqlite3_value **apVal /* Array of arguments */
|
| +){
|
| + Fts3Cursor *pCsr; /* Cursor handle passed through apVal[0] */
|
| +
|
| + UNUSED_PARAMETER(nVal);
|
| +
|
| + assert( nVal==1 );
|
| + if( fts3FunctionArg(pContext, "offsets", apVal[0], &pCsr) ) return;
|
| + assert( pCsr );
|
| + if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
|
| + sqlite3Fts3Offsets(pContext, pCsr);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Implementation of the special optimize() function for FTS3. This
|
| +** function merges all segments in the database to a single segment.
|
| +** Example usage is:
|
| +**
|
| +** SELECT optimize(t) FROM t LIMIT 1;
|
| +**
|
| +** where 't' is the name of an FTS3 table.
|
| +*/
|
| +static void fts3OptimizeFunc(
|
| + sqlite3_context *pContext, /* SQLite function call context */
|
| + int nVal, /* Size of argument array */
|
| + sqlite3_value **apVal /* Array of arguments */
|
| +){
|
| + int rc; /* Return code */
|
| + Fts3Table *p; /* Virtual table handle */
|
| + Fts3Cursor *pCursor; /* Cursor handle passed through apVal[0] */
|
| +
|
| + UNUSED_PARAMETER(nVal);
|
| +
|
| + assert( nVal==1 );
|
| + if( fts3FunctionArg(pContext, "optimize", apVal[0], &pCursor) ) return;
|
| + p = (Fts3Table *)pCursor->base.pVtab;
|
| + assert( p );
|
| +
|
| + rc = sqlite3Fts3Optimize(p);
|
| +
|
| + switch( rc ){
|
| + case SQLITE_OK:
|
| + sqlite3_result_text(pContext, "Index optimized", -1, SQLITE_STATIC);
|
| + break;
|
| + case SQLITE_DONE:
|
| + sqlite3_result_text(pContext, "Index already optimal", -1, SQLITE_STATIC);
|
| + break;
|
| + default:
|
| + sqlite3_result_error_code(pContext, rc);
|
| + break;
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** Implementation of the matchinfo() function for FTS3
|
| +*/
|
| +static void fts3MatchinfoFunc(
|
| + sqlite3_context *pContext, /* SQLite function call context */
|
| + int nVal, /* Size of argument array */
|
| + sqlite3_value **apVal /* Array of arguments */
|
| +){
|
| + Fts3Cursor *pCsr; /* Cursor handle passed through apVal[0] */
|
| + assert( nVal==1 || nVal==2 );
|
| + if( SQLITE_OK==fts3FunctionArg(pContext, "matchinfo", apVal[0], &pCsr) ){
|
| + const char *zArg = 0;
|
| + if( nVal>1 ){
|
| + zArg = (const char *)sqlite3_value_text(apVal[1]);
|
| + }
|
| + sqlite3Fts3Matchinfo(pContext, pCsr, zArg);
|
| + }
|
| +}
|
| +
|
| +/*
|
| +** This routine implements the xFindFunction method for the FTS3
|
| +** virtual table.
|
| +*/
|
| +static int fts3FindFunctionMethod(
|
| + sqlite3_vtab *pVtab, /* Virtual table handle */
|
| + int nArg, /* Number of SQL function arguments */
|
| + const char *zName, /* Name of SQL function */
|
| + void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), /* OUT: Result */
|
| + void **ppArg /* Unused */
|
| +){
|
| + struct Overloaded {
|
| + const char *zName;
|
| + void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
|
| + } aOverload[] = {
|
| + { "snippet", fts3SnippetFunc },
|
| + { "offsets", fts3OffsetsFunc },
|
| + { "optimize", fts3OptimizeFunc },
|
| + { "matchinfo", fts3MatchinfoFunc },
|
| + };
|
| + int i; /* Iterator variable */
|
| +
|
| + UNUSED_PARAMETER(pVtab);
|
| + UNUSED_PARAMETER(nArg);
|
| + UNUSED_PARAMETER(ppArg);
|
| +
|
| + for(i=0; i<SizeofArray(aOverload); i++){
|
| + if( strcmp(zName, aOverload[i].zName)==0 ){
|
| + *pxFunc = aOverload[i].xFunc;
|
| + return 1;
|
| + }
|
| + }
|
| +
|
| + /* No function of the specified name was found. Return 0. */
|
| + return 0;
|
| +}
|
| +
|
| +/*
|
| +** Implementation of FTS3 xRename method. Rename an fts3 table.
|
| +*/
|
| +static int fts3RenameMethod(
|
| + sqlite3_vtab *pVtab, /* Virtual table handle */
|
| + const char *zName /* New name of table */
|
| +){
|
| + Fts3Table *p = (Fts3Table *)pVtab;
|
| + sqlite3 *db = p->db; /* Database connection */
|
| + int rc; /* Return Code */
|
| +
|
| + rc = sqlite3Fts3PendingTermsFlush(p);
|
| + if( rc!=SQLITE_OK ){
|
| + return rc;
|
| + }
|
| +
|
| + fts3DbExec(&rc, db,
|
| + "ALTER TABLE %Q.'%q_content' RENAME TO '%q_content';",
|
| + p->zDb, p->zName, zName
|
| + );
|
| + if( p->bHasDocsize ){
|
| + fts3DbExec(&rc, db,
|
| + "ALTER TABLE %Q.'%q_docsize' RENAME TO '%q_docsize';",
|
| + p->zDb, p->zName, zName
|
| + );
|
| + }
|
| + if( p->bHasStat ){
|
| + fts3DbExec(&rc, db,
|
| + "ALTER TABLE %Q.'%q_stat' RENAME TO '%q_stat';",
|
| + p->zDb, p->zName, zName
|
| + );
|
| + }
|
| + fts3DbExec(&rc, db,
|
| + "ALTER TABLE %Q.'%q_segments' RENAME TO '%q_segments';",
|
| + p->zDb, p->zName, zName
|
| + );
|
| + fts3DbExec(&rc, db,
|
| + "ALTER TABLE %Q.'%q_segdir' RENAME TO '%q_segdir';",
|
| + p->zDb, p->zName, zName
|
| + );
|
| + return rc;
|
| +}
|
| +
|
| +static const sqlite3_module fts3Module = {
|
| + /* iVersion */ 0,
|
| + /* xCreate */ fts3CreateMethod,
|
| + /* xConnect */ fts3ConnectMethod,
|
| + /* xBestIndex */ fts3BestIndexMethod,
|
| + /* xDisconnect */ fts3DisconnectMethod,
|
| + /* xDestroy */ fts3DestroyMethod,
|
| + /* xOpen */ fts3OpenMethod,
|
| + /* xClose */ fts3CloseMethod,
|
| + /* xFilter */ fts3FilterMethod,
|
| + /* xNext */ fts3NextMethod,
|
| + /* xEof */ fts3EofMethod,
|
| + /* xColumn */ fts3ColumnMethod,
|
| + /* xRowid */ fts3RowidMethod,
|
| + /* xUpdate */ fts3UpdateMethod,
|
| + /* xBegin */ fts3BeginMethod,
|
| + /* xSync */ fts3SyncMethod,
|
| + /* xCommit */ fts3CommitMethod,
|
| + /* xRollback */ fts3RollbackMethod,
|
| + /* xFindFunction */ fts3FindFunctionMethod,
|
| + /* xRename */ fts3RenameMethod,
|
| +};
|
| +
|
| +/*
|
| +** This function is registered as the module destructor (called when an
|
| +** FTS3 enabled database connection is closed). It frees the memory
|
| +** allocated for the tokenizer hash table.
|
| +*/
|
| +static void hashDestroy(void *p){
|
| + Fts3Hash *pHash = (Fts3Hash *)p;
|
| + sqlite3Fts3HashClear(pHash);
|
| + sqlite3_free(pHash);
|
| +}
|
| +
|
| +/*
|
| +** The fts3 built-in tokenizers - "simple", "porter" and "icu"- are
|
| +** implemented in files fts3_tokenizer1.c, fts3_porter.c and fts3_icu.c
|
| +** respectively. The following three forward declarations are for functions
|
| +** declared in these files used to retrieve the respective implementations.
|
| +**
|
| +** Calling sqlite3Fts3SimpleTokenizerModule() sets the value pointed
|
| +** to by the argument to point to the "simple" tokenizer implementation.
|
| +** And so on.
|
| +*/
|
| +void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
|
| +void sqlite3Fts3PorterTokenizerModule(sqlite3_tokenizer_module const**ppModule);
|
| +#ifdef SQLITE_ENABLE_ICU
|
| +void sqlite3Fts3IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);
|
| +#endif
|
| +
|
| +/*
|
| +** Initialise the fts3 extension. If this extension is built as part
|
| +** of the sqlite library, then this function is called directly by
|
| +** SQLite. If fts3 is built as a dynamically loadable extension, this
|
| +** function is called by the sqlite3_extension_init() entry point.
|
| +*/
|
| +int sqlite3Fts3Init(sqlite3 *db){
|
| + int rc = SQLITE_OK;
|
| + Fts3Hash *pHash = 0;
|
| + const sqlite3_tokenizer_module *pSimple = 0;
|
| + const sqlite3_tokenizer_module *pPorter = 0;
|
| +
|
| +#ifdef SQLITE_ENABLE_ICU
|
| + const sqlite3_tokenizer_module *pIcu = 0;
|
| + sqlite3Fts3IcuTokenizerModule(&pIcu);
|
| +#endif
|
| +
|
| + rc = sqlite3Fts3InitAux(db);
|
| + if( rc!=SQLITE_OK ) return rc;
|
| +
|
| + sqlite3Fts3SimpleTokenizerModule(&pSimple);
|
| + sqlite3Fts3PorterTokenizerModule(&pPorter);
|
| +
|
| + /* Allocate and initialise the hash-table used to store tokenizers. */
|
| + pHash = sqlite3_malloc(sizeof(Fts3Hash));
|
| + if( !pHash ){
|
| + rc = SQLITE_NOMEM;
|
| + }else{
|
| + sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
|
| + }
|
| +
|
| + /* Load the built-in tokenizers into the hash table */
|
| + if( rc==SQLITE_OK ){
|
| + if( sqlite3Fts3HashInsert(pHash, "simple", 7, (void *)pSimple)
|
| + || sqlite3Fts3HashInsert(pHash, "porter", 7, (void *)pPorter)
|
| +#ifdef SQLITE_ENABLE_ICU
|
| + || (pIcu && sqlite3Fts3HashInsert(pHash, "icu", 4, (void *)pIcu))
|
| +#endif
|
| + ){
|
| + rc = SQLITE_NOMEM;
|
| + }
|
| + }
|
| +
|
| +#ifdef SQLITE_TEST
|
| + if( rc==SQLITE_OK ){
|
| + rc = sqlite3Fts3ExprInitTestInterface(db);
|
| + }
|
| +#endif
|
| +
|
| + /* Create the virtual table wrapper around the hash-table and overload
|
| + ** the two scalar functions. If this is successful, register the
|
| + ** module with sqlite.
|
| + */
|
| + if( SQLITE_OK==rc
|
| + && SQLITE_OK==(rc = sqlite3Fts3InitHashTable(db, pHash, "fts3_tokenizer"))
|
| + && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
|
| + && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", 1))
|
| + && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 1))
|
| + && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 2))
|
| + && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", 1))
|
| + ){
|
| + rc = sqlite3_create_module_v2(
|
| + db, "fts3", &fts3Module, (void *)pHash, hashDestroy
|
| + );
|
| + if( rc==SQLITE_OK ){
|
| + rc = sqlite3_create_module_v2(
|
| + db, "fts4", &fts3Module, (void *)pHash, 0
|
| + );
|
| + }
|
| + return rc;
|
| + }
|
| +
|
| + /* An error has occurred. Delete the hash table and return the error code. */
|
| + assert( rc!=SQLITE_OK );
|
| + if( pHash ){
|
| + sqlite3Fts3HashClear(pHash);
|
| + sqlite3_free(pHash);
|
| + }
|
| + return rc;
|
| +}
|
| +
|
| +#if !SQLITE_CORE
|
| +int sqlite3_extension_init(
|
| + sqlite3 *db,
|
| + char **pzErrMsg,
|
| + const sqlite3_api_routines *pApi
|
| +){
|
| + SQLITE_EXTENSION_INIT2(pApi)
|
| + return sqlite3Fts3Init(db);
|
| +}
|
| +#endif
|
| +
|
| +#endif
|
|
|
Chromium Code Reviews
Issue 949043002:
Add //third_party/sqlite to dirs_to_snapshot, remove net_sql.patch (Closed)
Base URL: git@github.com:domokit/mojo.git@master