[sql] Import reference version of SQLite 3.8.7.4.

third_party/sqlite/sqlite-src-3080704/ext/fts3/fts3_term.c

+/*
+** 2011 Jan 27
+**
+** 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 file is not part of the production FTS code. It is only used for
+** testing. It contains a virtual table implementation that provides direct 
+** access to the full-text index of an FTS table. 
+*/
+
+#include "fts3Int.h"
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+#ifdef SQLITE_TEST
+
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+
+typedef struct Fts3termTable Fts3termTable;
+typedef struct Fts3termCursor Fts3termCursor;
+
+struct Fts3termTable {
+  sqlite3_vtab base;              /* Base class used by SQLite core */
+  int iIndex;                     /* Index for Fts3Table.aIndex[] */
+  Fts3Table *pFts3Tab;
+};
+
+struct Fts3termCursor {
+  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
+  Fts3MultiSegReader csr;        /* Must be right after "base" */
+  Fts3SegFilter filter;
+
+  int isEof;                      /* True if cursor is at EOF */
+  char *pNext;
+
+  sqlite3_int64 iRowid;           /* Current 'rowid' value */
+  sqlite3_int64 iDocid;           /* Current 'docid' value */
+  int iCol;                       /* Current 'col' value */
+  int iPos;                       /* Current 'pos' value */
+};
+
+/*
+** Schema of the terms table.
+*/
+#define FTS3_TERMS_SCHEMA "CREATE TABLE x(term, docid, col, pos)"
+
+/*
+** This function does all the work for both the xConnect and xCreate methods.
+** These tables have no persistent representation of their own, so xConnect
+** and xCreate are identical operations.
+*/
+static int fts3termConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pCtx,                     /* Non-zero for an fts4prefix 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 */
+){
+  char const *zDb;                /* Name of database (e.g. "main") */
+  char const *zFts3;              /* Name of fts3 table */
+  int nDb;                        /* Result of strlen(zDb) */
+  int nFts3;                      /* Result of strlen(zFts3) */
+  int nByte;                      /* Bytes of space to allocate here */
+  int rc;                         /* value returned by declare_vtab() */
+  Fts3termTable *p;                /* Virtual table object to return */
+  int iIndex = 0;
+
+  UNUSED_PARAMETER(pCtx);
+  if( argc==5 ){
+    iIndex = atoi(argv[4]);
+    argc--;
+  }
+
+  /* The user should specify a single argument - the name of an fts3 table. */
+  if( argc!=4 ){
+    *pzErr = sqlite3_mprintf(
+        "wrong number of arguments to fts4term constructor"
+    );
+    return SQLITE_ERROR;
+  }
+
+  zDb = argv[1]; 
+  nDb = (int)strlen(zDb);
+  zFts3 = argv[3];
+  nFts3 = (int)strlen(zFts3);
+
+  rc = sqlite3_declare_vtab(db, FTS3_TERMS_SCHEMA);
+  if( rc!=SQLITE_OK ) return rc;
+
+  nByte = sizeof(Fts3termTable) + sizeof(Fts3Table) + nDb + nFts3 + 2;
+  p = (Fts3termTable *)sqlite3_malloc(nByte);
+  if( !p ) return SQLITE_NOMEM;
+  memset(p, 0, nByte);
+
+  p->pFts3Tab = (Fts3Table *)&p[1];
+  p->pFts3Tab->zDb = (char *)&p->pFts3Tab[1];
+  p->pFts3Tab->zName = &p->pFts3Tab->zDb[nDb+1];
+  p->pFts3Tab->db = db;
+  p->pFts3Tab->nIndex = iIndex+1;
+  p->iIndex = iIndex;
+
+  memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);
+  memcpy((char *)p->pFts3Tab->zName, zFts3, nFts3);
+  sqlite3Fts3Dequote((char *)p->pFts3Tab->zName);
+
+  *ppVtab = (sqlite3_vtab *)p;
+  return SQLITE_OK;
+}
+
+/*
+** This function does the work for both the xDisconnect and xDestroy methods.
+** These tables have no persistent representation of their own, so xDisconnect
+** and xDestroy are identical operations.
+*/
+static int fts3termDisconnectMethod(sqlite3_vtab *pVtab){
+  Fts3termTable *p = (Fts3termTable *)pVtab;
+  Fts3Table *pFts3 = p->pFts3Tab;
+  int i;
+
+  /* Free any prepared statements held */
+  for(i=0; i<SizeofArray(pFts3->aStmt); i++){
+    sqlite3_finalize(pFts3->aStmt[i]);
+  }
+  sqlite3_free(pFts3->zSegmentsTbl);
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+#define FTS4AUX_EQ_CONSTRAINT 1
+#define FTS4AUX_GE_CONSTRAINT 2
+#define FTS4AUX_LE_CONSTRAINT 4
+
+/*
+** xBestIndex - Analyze a WHERE and ORDER BY clause.
+*/
+static int fts3termBestIndexMethod(
+  sqlite3_vtab *pVTab, 
+  sqlite3_index_info *pInfo
+){
+  UNUSED_PARAMETER(pVTab);
+
+  /* This vtab naturally does "ORDER BY term, docid, col, pos".  */
+  if( pInfo->nOrderBy ){
+    int i;
+    for(i=0; i<pInfo->nOrderBy; i++){
+      if( pInfo->aOrderBy[i].iColumn!=i || pInfo->aOrderBy[i].desc ) break;
+    }
+    if( i==pInfo->nOrderBy ){
+      pInfo->orderByConsumed = 1;
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** xOpen - Open a cursor.
+*/
+static int fts3termOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  Fts3termCursor *pCsr;            /* Pointer to cursor object to return */
+
+  UNUSED_PARAMETER(pVTab);
+
+  pCsr = (Fts3termCursor *)sqlite3_malloc(sizeof(Fts3termCursor));
+  if( !pCsr ) return SQLITE_NOMEM;
+  memset(pCsr, 0, sizeof(Fts3termCursor));
+
+  *ppCsr = (sqlite3_vtab_cursor *)pCsr;
+  return SQLITE_OK;
+}
+
+/*
+** xClose - Close a cursor.
+*/
+static int fts3termCloseMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3Table *pFts3 = ((Fts3termTable *)pCursor->pVtab)->pFts3Tab;
+  Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
+
+  sqlite3Fts3SegmentsClose(pFts3);
+  sqlite3Fts3SegReaderFinish(&pCsr->csr);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** xNext - Advance the cursor to the next row, if any.
+*/
+static int fts3termNextMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
+  Fts3Table *pFts3 = ((Fts3termTable *)pCursor->pVtab)->pFts3Tab;
+  int rc;
+  sqlite3_int64 v;
+
+  /* Increment our pretend rowid value. */
+  pCsr->iRowid++;
+
+  /* Advance to the next term in the full-text index. */
+  if( pCsr->csr.aDoclist==0 
+   || pCsr->pNext>=&pCsr->csr.aDoclist[pCsr->csr.nDoclist-1]
+  ){
+    rc = sqlite3Fts3SegReaderStep(pFts3, &pCsr->csr);
+    if( rc!=SQLITE_ROW ){
+      pCsr->isEof = 1;
+      return rc;
+    }
+
+    pCsr->iCol = 0;
+    pCsr->iPos = 0;
+    pCsr->iDocid = 0;
+    pCsr->pNext = pCsr->csr.aDoclist;
+
+    /* Read docid */
+    pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &pCsr->iDocid);
+  }
+
+  pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
+  if( v==0 ){
+    pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
+    pCsr->iDocid += v;
+    pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
+    pCsr->iCol = 0;
+    pCsr->iPos = 0;
+  }
+
+  if( v==1 ){
+    pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
+    pCsr->iCol += (int)v;
+    pCsr->iPos = 0;
+    pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
+  }
+
+  pCsr->iPos += (int)(v - 2);
+
+  return SQLITE_OK;
+}
+
+/*
+** xFilter - Initialize a cursor to point at the start of its data.
+*/
+static int fts3termFilterMethod(
+  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 */
+){
+  Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
+  Fts3termTable *p = (Fts3termTable *)pCursor->pVtab;
+  Fts3Table *pFts3 = p->pFts3Tab;
+  int rc;
+
+  UNUSED_PARAMETER(nVal);
+  UNUSED_PARAMETER(idxNum);
+  UNUSED_PARAMETER(idxStr);
+  UNUSED_PARAMETER(apVal);
+
+  assert( idxStr==0 && idxNum==0 );
+
+  /* In case this cursor is being reused, close and zero it. */
+  testcase(pCsr->filter.zTerm);
+  sqlite3Fts3SegReaderFinish(&pCsr->csr);
+  memset(&pCsr->csr, 0, ((u8*)&pCsr[1]) - (u8*)&pCsr->csr);
+
+  pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
+  pCsr->filter.flags |= FTS3_SEGMENT_SCAN;
+
+  rc = sqlite3Fts3SegReaderCursor(pFts3, 0, p->iIndex, FTS3_SEGCURSOR_ALL,
+      pCsr->filter.zTerm, pCsr->filter.nTerm, 0, 1, &pCsr->csr
+  );
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter);
+  }
+  if( rc==SQLITE_OK ){
+    rc = fts3termNextMethod(pCursor);
+  }
+  return rc;
+}
+
+/*
+** xEof - Return true if the cursor is at EOF, or false otherwise.
+*/
+static int fts3termEofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
+  return pCsr->isEof;
+}
+
+/*
+** xColumn - Return a column value.
+*/
+static int fts3termColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  Fts3termCursor *p = (Fts3termCursor *)pCursor;
+
+  assert( iCol>=0 && iCol<=3 );
+  switch( iCol ){
+    case 0:
+      sqlite3_result_text(pCtx, p->csr.zTerm, p->csr.nTerm, SQLITE_TRANSIENT);
+      break;
+    case 1:
+      sqlite3_result_int64(pCtx, p->iDocid);
+      break;
+    case 2:
+      sqlite3_result_int64(pCtx, p->iCol);
+      break;
+    default:
+      sqlite3_result_int64(pCtx, p->iPos);
+      break;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** xRowid - Return the current rowid for the cursor.
+*/
+static int fts3termRowidMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite_int64 *pRowid            /* OUT: Rowid value */
+){
+  Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
+  *pRowid = pCsr->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Register the fts3term module with database connection db. Return SQLITE_OK
+** if successful or an error code if sqlite3_create_module() fails.
+*/
+int sqlite3Fts3InitTerm(sqlite3 *db){
+  static const sqlite3_module fts3term_module = {
+     0,                           /* iVersion      */
+     fts3termConnectMethod,       /* xCreate       */
+     fts3termConnectMethod,       /* xConnect      */
+     fts3termBestIndexMethod,     /* xBestIndex    */
+     fts3termDisconnectMethod,    /* xDisconnect   */
+     fts3termDisconnectMethod,    /* xDestroy      */
+     fts3termOpenMethod,          /* xOpen         */
+     fts3termCloseMethod,         /* xClose        */
+     fts3termFilterMethod,        /* xFilter       */
+     fts3termNextMethod,          /* xNext         */
+     fts3termEofMethod,           /* xEof          */
+     fts3termColumnMethod,        /* xColumn       */
+     fts3termRowidMethod,         /* xRowid        */
+     0,                           /* xUpdate       */
+     0,                           /* xBegin        */
+     0,                           /* xSync         */
+     0,                           /* xCommit       */
+     0,                           /* xRollback     */
+     0,                           /* xFindFunction */
+     0,                           /* xRename       */
+     0,                           /* xSavepoint    */
+     0,                           /* xRelease      */
+     0                            /* xRollbackTo   */
+  };
+  int rc;                         /* Return code */
+
+  rc = sqlite3_create_module(db, "fts4term", &fts3term_module, 0);
+  return rc;
+}
+
+#endif
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */