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Unified Diff: third_party/sqlite/sqlite-src-3170000/src/whereexpr.c

Issue 2747283002: [sql] Import reference version of SQLite 3.17.. (Closed)
Patch Set: Created 3 years, 9 months ago
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Index: third_party/sqlite/sqlite-src-3170000/src/whereexpr.c
diff --git a/third_party/sqlite/sqlite-src-3170000/src/whereexpr.c b/third_party/sqlite/sqlite-src-3170000/src/whereexpr.c
new file mode 100644
index 0000000000000000000000000000000000000000..826d329b7f1d8f91c942e053ef531e38815093b3
--- /dev/null
+++ b/third_party/sqlite/sqlite-src-3170000/src/whereexpr.c
@@ -0,0 +1,1445 @@
+/*
+** 2015-06-08
+**
+** 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 module contains C code that generates VDBE code used to process
+** the WHERE clause of SQL statements.
+**
+** This file was originally part of where.c but was split out to improve
+** readability and editabiliity. This file contains utility routines for
+** analyzing Expr objects in the WHERE clause.
+*/
+#include "sqliteInt.h"
+#include "whereInt.h"
+
+/* Forward declarations */
+static void exprAnalyze(SrcList*, WhereClause*, int);
+
+/*
+** Deallocate all memory associated with a WhereOrInfo object.
+*/
+static void whereOrInfoDelete(sqlite3 *db, WhereOrInfo *p){
+ sqlite3WhereClauseClear(&p->wc);
+ sqlite3DbFree(db, p);
+}
+
+/*
+** Deallocate all memory associated with a WhereAndInfo object.
+*/
+static void whereAndInfoDelete(sqlite3 *db, WhereAndInfo *p){
+ sqlite3WhereClauseClear(&p->wc);
+ sqlite3DbFree(db, p);
+}
+
+/*
+** Add a single new WhereTerm entry to the WhereClause object pWC.
+** The new WhereTerm object is constructed from Expr p and with wtFlags.
+** The index in pWC->a[] of the new WhereTerm is returned on success.
+** 0 is returned if the new WhereTerm could not be added due to a memory
+** allocation error. The memory allocation failure will be recorded in
+** the db->mallocFailed flag so that higher-level functions can detect it.
+**
+** This routine will increase the size of the pWC->a[] array as necessary.
+**
+** If the wtFlags argument includes TERM_DYNAMIC, then responsibility
+** for freeing the expression p is assumed by the WhereClause object pWC.
+** This is true even if this routine fails to allocate a new WhereTerm.
+**
+** WARNING: This routine might reallocate the space used to store
+** WhereTerms. All pointers to WhereTerms should be invalidated after
+** calling this routine. Such pointers may be reinitialized by referencing
+** the pWC->a[] array.
+*/
+static int whereClauseInsert(WhereClause *pWC, Expr *p, u16 wtFlags){
+ WhereTerm *pTerm;
+ int idx;
+ testcase( wtFlags & TERM_VIRTUAL );
+ if( pWC->nTerm>=pWC->nSlot ){
+ WhereTerm *pOld = pWC->a;
+ sqlite3 *db = pWC->pWInfo->pParse->db;
+ pWC->a = sqlite3DbMallocRawNN(db, sizeof(pWC->a[0])*pWC->nSlot*2 );
+ if( pWC->a==0 ){
+ if( wtFlags & TERM_DYNAMIC ){
+ sqlite3ExprDelete(db, p);
+ }
+ pWC->a = pOld;
+ return 0;
+ }
+ memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm);
+ if( pOld!=pWC->aStatic ){
+ sqlite3DbFree(db, pOld);
+ }
+ pWC->nSlot = sqlite3DbMallocSize(db, pWC->a)/sizeof(pWC->a[0]);
+ }
+ pTerm = &pWC->a[idx = pWC->nTerm++];
+ if( p && ExprHasProperty(p, EP_Unlikely) ){
+ pTerm->truthProb = sqlite3LogEst(p->iTable) - 270;
+ }else{
+ pTerm->truthProb = 1;
+ }
+ pTerm->pExpr = sqlite3ExprSkipCollate(p);
+ pTerm->wtFlags = wtFlags;
+ pTerm->pWC = pWC;
+ pTerm->iParent = -1;
+ memset(&pTerm->eOperator, 0,
+ sizeof(WhereTerm) - offsetof(WhereTerm,eOperator));
+ return idx;
+}
+
+/*
+** Return TRUE if the given operator is one of the operators that is
+** allowed for an indexable WHERE clause term. The allowed operators are
+** "=", "<", ">", "<=", ">=", "IN", "IS", and "IS NULL"
+*/
+static int allowedOp(int op){
+ assert( TK_GT>TK_EQ && TK_GT<TK_GE );
+ assert( TK_LT>TK_EQ && TK_LT<TK_GE );
+ assert( TK_LE>TK_EQ && TK_LE<TK_GE );
+ assert( TK_GE==TK_EQ+4 );
+ return op==TK_IN || (op>=TK_EQ && op<=TK_GE) || op==TK_ISNULL || op==TK_IS;
+}
+
+/*
+** Commute a comparison operator. Expressions of the form "X op Y"
+** are converted into "Y op X".
+**
+** If left/right precedence rules come into play when determining the
+** collating sequence, then COLLATE operators are adjusted to ensure
+** that the collating sequence does not change. For example:
+** "Y collate NOCASE op X" becomes "X op Y" because any collation sequence on
+** the left hand side of a comparison overrides any collation sequence
+** attached to the right. For the same reason the EP_Collate flag
+** is not commuted.
+*/
+static void exprCommute(Parse *pParse, Expr *pExpr){
+ u16 expRight = (pExpr->pRight->flags & EP_Collate);
+ u16 expLeft = (pExpr->pLeft->flags & EP_Collate);
+ assert( allowedOp(pExpr->op) && pExpr->op!=TK_IN );
+ if( expRight==expLeft ){
+ /* Either X and Y both have COLLATE operator or neither do */
+ if( expRight ){
+ /* Both X and Y have COLLATE operators. Make sure X is always
+ ** used by clearing the EP_Collate flag from Y. */
+ pExpr->pRight->flags &= ~EP_Collate;
+ }else if( sqlite3ExprCollSeq(pParse, pExpr->pLeft)!=0 ){
+ /* Neither X nor Y have COLLATE operators, but X has a non-default
+ ** collating sequence. So add the EP_Collate marker on X to cause
+ ** it to be searched first. */
+ pExpr->pLeft->flags |= EP_Collate;
+ }
+ }
+ SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
+ if( pExpr->op>=TK_GT ){
+ assert( TK_LT==TK_GT+2 );
+ assert( TK_GE==TK_LE+2 );
+ assert( TK_GT>TK_EQ );
+ assert( TK_GT<TK_LE );
+ assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE );
+ pExpr->op = ((pExpr->op-TK_GT)^2)+TK_GT;
+ }
+}
+
+/*
+** Translate from TK_xx operator to WO_xx bitmask.
+*/
+static u16 operatorMask(int op){
+ u16 c;
+ assert( allowedOp(op) );
+ if( op==TK_IN ){
+ c = WO_IN;
+ }else if( op==TK_ISNULL ){
+ c = WO_ISNULL;
+ }else if( op==TK_IS ){
+ c = WO_IS;
+ }else{
+ assert( (WO_EQ<<(op-TK_EQ)) < 0x7fff );
+ c = (u16)(WO_EQ<<(op-TK_EQ));
+ }
+ assert( op!=TK_ISNULL || c==WO_ISNULL );
+ assert( op!=TK_IN || c==WO_IN );
+ assert( op!=TK_EQ || c==WO_EQ );
+ assert( op!=TK_LT || c==WO_LT );
+ assert( op!=TK_LE || c==WO_LE );
+ assert( op!=TK_GT || c==WO_GT );
+ assert( op!=TK_GE || c==WO_GE );
+ assert( op!=TK_IS || c==WO_IS );
+ return c;
+}
+
+
+#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
+/*
+** Check to see if the given expression is a LIKE or GLOB operator that
+** can be optimized using inequality constraints. Return TRUE if it is
+** so and false if not.
+**
+** In order for the operator to be optimizible, the RHS must be a string
+** literal that does not begin with a wildcard. The LHS must be a column
+** that may only be NULL, a string, or a BLOB, never a number. (This means
+** that virtual tables cannot participate in the LIKE optimization.) The
+** collating sequence for the column on the LHS must be appropriate for
+** the operator.
+*/
+static int isLikeOrGlob(
+ Parse *pParse, /* Parsing and code generating context */
+ Expr *pExpr, /* Test this expression */
+ Expr **ppPrefix, /* Pointer to TK_STRING expression with pattern prefix */
+ int *pisComplete, /* True if the only wildcard is % in the last character */
+ int *pnoCase /* True if uppercase is equivalent to lowercase */
+){
+ const char *z = 0; /* String on RHS of LIKE operator */
+ Expr *pRight, *pLeft; /* Right and left size of LIKE operator */
+ ExprList *pList; /* List of operands to the LIKE operator */
+ int c; /* One character in z[] */
+ int cnt; /* Number of non-wildcard prefix characters */
+ char wc[3]; /* Wildcard characters */
+ sqlite3 *db = pParse->db; /* Database connection */
+ sqlite3_value *pVal = 0;
+ int op; /* Opcode of pRight */
+ int rc; /* Result code to return */
+
+ if( !sqlite3IsLikeFunction(db, pExpr, pnoCase, wc) ){
+ return 0;
+ }
+#ifdef SQLITE_EBCDIC
+ if( *pnoCase ) return 0;
+#endif
+ pList = pExpr->x.pList;
+ pLeft = pList->a[1].pExpr;
+ if( pLeft->op!=TK_COLUMN
+ || sqlite3ExprAffinity(pLeft)!=SQLITE_AFF_TEXT
+ || IsVirtual(pLeft->pTab) /* Value might be numeric */
+ ){
+ /* IMP: R-02065-49465 The left-hand side of the LIKE or GLOB operator must
+ ** be the name of an indexed column with TEXT affinity. */
+ return 0;
+ }
+ assert( pLeft->iColumn!=(-1) ); /* Because IPK never has AFF_TEXT */
+
+ pRight = sqlite3ExprSkipCollate(pList->a[0].pExpr);
+ op = pRight->op;
+ if( op==TK_VARIABLE ){
+ Vdbe *pReprepare = pParse->pReprepare;
+ int iCol = pRight->iColumn;
+ pVal = sqlite3VdbeGetBoundValue(pReprepare, iCol, SQLITE_AFF_BLOB);
+ if( pVal && sqlite3_value_type(pVal)==SQLITE_TEXT ){
+ z = (char *)sqlite3_value_text(pVal);
+ }
+ sqlite3VdbeSetVarmask(pParse->pVdbe, iCol);
+ assert( pRight->op==TK_VARIABLE || pRight->op==TK_REGISTER );
+ }else if( op==TK_STRING ){
+ z = pRight->u.zToken;
+ }
+ if( z ){
+ cnt = 0;
+ while( (c=z[cnt])!=0 && c!=wc[0] && c!=wc[1] && c!=wc[2] ){
+ cnt++;
+ }
+ if( cnt!=0 && 255!=(u8)z[cnt-1] ){
+ Expr *pPrefix;
+ *pisComplete = c==wc[0] && z[cnt+1]==0;
+ pPrefix = sqlite3Expr(db, TK_STRING, z);
+ if( pPrefix ) pPrefix->u.zToken[cnt] = 0;
+ *ppPrefix = pPrefix;
+ if( op==TK_VARIABLE ){
+ Vdbe *v = pParse->pVdbe;
+ sqlite3VdbeSetVarmask(v, pRight->iColumn);
+ if( *pisComplete && pRight->u.zToken[1] ){
+ /* If the rhs of the LIKE expression is a variable, and the current
+ ** value of the variable means there is no need to invoke the LIKE
+ ** function, then no OP_Variable will be added to the program.
+ ** This causes problems for the sqlite3_bind_parameter_name()
+ ** API. To work around them, add a dummy OP_Variable here.
+ */
+ int r1 = sqlite3GetTempReg(pParse);
+ sqlite3ExprCodeTarget(pParse, pRight, r1);
+ sqlite3VdbeChangeP3(v, sqlite3VdbeCurrentAddr(v)-1, 0);
+ sqlite3ReleaseTempReg(pParse, r1);
+ }
+ }
+ }else{
+ z = 0;
+ }
+ }
+
+ rc = (z!=0);
+ sqlite3ValueFree(pVal);
+ return rc;
+}
+#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
+
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Check to see if the given expression is of the form
+**
+** column OP expr
+**
+** where OP is one of MATCH, GLOB, LIKE or REGEXP and "column" is a
+** column of a virtual table.
+**
+** If it is then return TRUE. If not, return FALSE.
+*/
+static int isMatchOfColumn(
+ Expr *pExpr, /* Test this expression */
+ unsigned char *peOp2 /* OUT: 0 for MATCH, or else an op2 value */
+){
+ static const struct Op2 {
+ const char *zOp;
+ unsigned char eOp2;
+ } aOp[] = {
+ { "match", SQLITE_INDEX_CONSTRAINT_MATCH },
+ { "glob", SQLITE_INDEX_CONSTRAINT_GLOB },
+ { "like", SQLITE_INDEX_CONSTRAINT_LIKE },
+ { "regexp", SQLITE_INDEX_CONSTRAINT_REGEXP }
+ };
+ ExprList *pList;
+ Expr *pCol; /* Column reference */
+ int i;
+
+ if( pExpr->op!=TK_FUNCTION ){
+ return 0;
+ }
+ pList = pExpr->x.pList;
+ if( pList==0 || pList->nExpr!=2 ){
+ return 0;
+ }
+ pCol = pList->a[1].pExpr;
+ if( pCol->op!=TK_COLUMN || !IsVirtual(pCol->pTab) ){
+ return 0;
+ }
+ for(i=0; i<ArraySize(aOp); i++){
+ if( sqlite3StrICmp(pExpr->u.zToken, aOp[i].zOp)==0 ){
+ *peOp2 = aOp[i].eOp2;
+ return 1;
+ }
+ }
+ return 0;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/*
+** If the pBase expression originated in the ON or USING clause of
+** a join, then transfer the appropriate markings over to derived.
+*/
+static void transferJoinMarkings(Expr *pDerived, Expr *pBase){
+ if( pDerived ){
+ pDerived->flags |= pBase->flags & EP_FromJoin;
+ pDerived->iRightJoinTable = pBase->iRightJoinTable;
+ }
+}
+
+/*
+** Mark term iChild as being a child of term iParent
+*/
+static void markTermAsChild(WhereClause *pWC, int iChild, int iParent){
+ pWC->a[iChild].iParent = iParent;
+ pWC->a[iChild].truthProb = pWC->a[iParent].truthProb;
+ pWC->a[iParent].nChild++;
+}
+
+/*
+** Return the N-th AND-connected subterm of pTerm. Or if pTerm is not
+** a conjunction, then return just pTerm when N==0. If N is exceeds
+** the number of available subterms, return NULL.
+*/
+static WhereTerm *whereNthSubterm(WhereTerm *pTerm, int N){
+ if( pTerm->eOperator!=WO_AND ){
+ return N==0 ? pTerm : 0;
+ }
+ if( N<pTerm->u.pAndInfo->wc.nTerm ){
+ return &pTerm->u.pAndInfo->wc.a[N];
+ }
+ return 0;
+}
+
+/*
+** Subterms pOne and pTwo are contained within WHERE clause pWC. The
+** two subterms are in disjunction - they are OR-ed together.
+**
+** If these two terms are both of the form: "A op B" with the same
+** A and B values but different operators and if the operators are
+** compatible (if one is = and the other is <, for example) then
+** add a new virtual AND term to pWC that is the combination of the
+** two.
+**
+** Some examples:
+**
+** x<y OR x=y --> x<=y
+** x=y OR x=y --> x=y
+** x<=y OR x<y --> x<=y
+**
+** The following is NOT generated:
+**
+** x<y OR x>y --> x!=y
+*/
+static void whereCombineDisjuncts(
+ SrcList *pSrc, /* the FROM clause */
+ WhereClause *pWC, /* The complete WHERE clause */
+ WhereTerm *pOne, /* First disjunct */
+ WhereTerm *pTwo /* Second disjunct */
+){
+ u16 eOp = pOne->eOperator | pTwo->eOperator;
+ sqlite3 *db; /* Database connection (for malloc) */
+ Expr *pNew; /* New virtual expression */
+ int op; /* Operator for the combined expression */
+ int idxNew; /* Index in pWC of the next virtual term */
+
+ if( (pOne->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE))==0 ) return;
+ if( (pTwo->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE))==0 ) return;
+ if( (eOp & (WO_EQ|WO_LT|WO_LE))!=eOp
+ && (eOp & (WO_EQ|WO_GT|WO_GE))!=eOp ) return;
+ assert( pOne->pExpr->pLeft!=0 && pOne->pExpr->pRight!=0 );
+ assert( pTwo->pExpr->pLeft!=0 && pTwo->pExpr->pRight!=0 );
+ if( sqlite3ExprCompare(pOne->pExpr->pLeft, pTwo->pExpr->pLeft, -1) ) return;
+ if( sqlite3ExprCompare(pOne->pExpr->pRight, pTwo->pExpr->pRight, -1) )return;
+ /* If we reach this point, it means the two subterms can be combined */
+ if( (eOp & (eOp-1))!=0 ){
+ if( eOp & (WO_LT|WO_LE) ){
+ eOp = WO_LE;
+ }else{
+ assert( eOp & (WO_GT|WO_GE) );
+ eOp = WO_GE;
+ }
+ }
+ db = pWC->pWInfo->pParse->db;
+ pNew = sqlite3ExprDup(db, pOne->pExpr, 0);
+ if( pNew==0 ) return;
+ for(op=TK_EQ; eOp!=(WO_EQ<<(op-TK_EQ)); op++){ assert( op<TK_GE ); }
+ pNew->op = op;
+ idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
+ exprAnalyze(pSrc, pWC, idxNew);
+}
+
+#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
+/*
+** Analyze a term that consists of two or more OR-connected
+** subterms. So in:
+**
+** ... WHERE (a=5) AND (b=7 OR c=9 OR d=13) AND (d=13)
+** ^^^^^^^^^^^^^^^^^^^^
+**
+** This routine analyzes terms such as the middle term in the above example.
+** A WhereOrTerm object is computed and attached to the term under
+** analysis, regardless of the outcome of the analysis. Hence:
+**
+** WhereTerm.wtFlags |= TERM_ORINFO
+** WhereTerm.u.pOrInfo = a dynamically allocated WhereOrTerm object
+**
+** The term being analyzed must have two or more of OR-connected subterms.
+** A single subterm might be a set of AND-connected sub-subterms.
+** Examples of terms under analysis:
+**
+** (A) t1.x=t2.y OR t1.x=t2.z OR t1.y=15 OR t1.z=t3.a+5
+** (B) x=expr1 OR expr2=x OR x=expr3
+** (C) t1.x=t2.y OR (t1.x=t2.z AND t1.y=15)
+** (D) x=expr1 OR (y>11 AND y<22 AND z LIKE '*hello*')
+** (E) (p.a=1 AND q.b=2 AND r.c=3) OR (p.x=4 AND q.y=5 AND r.z=6)
+** (F) x>A OR (x=A AND y>=B)
+**
+** CASE 1:
+**
+** If all subterms are of the form T.C=expr for some single column of C and
+** a single table T (as shown in example B above) then create a new virtual
+** term that is an equivalent IN expression. In other words, if the term
+** being analyzed is:
+**
+** x = expr1 OR expr2 = x OR x = expr3
+**
+** then create a new virtual term like this:
+**
+** x IN (expr1,expr2,expr3)
+**
+** CASE 2:
+**
+** If there are exactly two disjuncts and one side has x>A and the other side
+** has x=A (for the same x and A) then add a new virtual conjunct term to the
+** WHERE clause of the form "x>=A". Example:
+**
+** x>A OR (x=A AND y>B) adds: x>=A
+**
+** The added conjunct can sometimes be helpful in query planning.
+**
+** CASE 3:
+**
+** If all subterms are indexable by a single table T, then set
+**
+** WhereTerm.eOperator = WO_OR
+** WhereTerm.u.pOrInfo->indexable |= the cursor number for table T
+**
+** A subterm is "indexable" if it is of the form
+** "T.C <op> <expr>" where C is any column of table T and
+** <op> is one of "=", "<", "<=", ">", ">=", "IS NULL", or "IN".
+** A subterm is also indexable if it is an AND of two or more
+** subsubterms at least one of which is indexable. Indexable AND
+** subterms have their eOperator set to WO_AND and they have
+** u.pAndInfo set to a dynamically allocated WhereAndTerm object.
+**
+** From another point of view, "indexable" means that the subterm could
+** potentially be used with an index if an appropriate index exists.
+** This analysis does not consider whether or not the index exists; that
+** is decided elsewhere. This analysis only looks at whether subterms
+** appropriate for indexing exist.
+**
+** All examples A through E above satisfy case 3. But if a term
+** also satisfies case 1 (such as B) we know that the optimizer will
+** always prefer case 1, so in that case we pretend that case 3 is not
+** satisfied.
+**
+** It might be the case that multiple tables are indexable. For example,
+** (E) above is indexable on tables P, Q, and R.
+**
+** Terms that satisfy case 3 are candidates for lookup by using
+** separate indices to find rowids for each subterm and composing
+** the union of all rowids using a RowSet object. This is similar
+** to "bitmap indices" in other database engines.
+**
+** OTHERWISE:
+**
+** If none of cases 1, 2, or 3 apply, then leave the eOperator set to
+** zero. This term is not useful for search.
+*/
+static void exprAnalyzeOrTerm(
+ SrcList *pSrc, /* the FROM clause */
+ WhereClause *pWC, /* the complete WHERE clause */
+ int idxTerm /* Index of the OR-term to be analyzed */
+){
+ WhereInfo *pWInfo = pWC->pWInfo; /* WHERE clause processing context */
+ Parse *pParse = pWInfo->pParse; /* Parser context */
+ sqlite3 *db = pParse->db; /* Database connection */
+ WhereTerm *pTerm = &pWC->a[idxTerm]; /* The term to be analyzed */
+ Expr *pExpr = pTerm->pExpr; /* The expression of the term */
+ int i; /* Loop counters */
+ WhereClause *pOrWc; /* Breakup of pTerm into subterms */
+ WhereTerm *pOrTerm; /* A Sub-term within the pOrWc */
+ WhereOrInfo *pOrInfo; /* Additional information associated with pTerm */
+ Bitmask chngToIN; /* Tables that might satisfy case 1 */
+ Bitmask indexable; /* Tables that are indexable, satisfying case 2 */
+
+ /*
+ ** Break the OR clause into its separate subterms. The subterms are
+ ** stored in a WhereClause structure containing within the WhereOrInfo
+ ** object that is attached to the original OR clause term.
+ */
+ assert( (pTerm->wtFlags & (TERM_DYNAMIC|TERM_ORINFO|TERM_ANDINFO))==0 );
+ assert( pExpr->op==TK_OR );
+ pTerm->u.pOrInfo = pOrInfo = sqlite3DbMallocZero(db, sizeof(*pOrInfo));
+ if( pOrInfo==0 ) return;
+ pTerm->wtFlags |= TERM_ORINFO;
+ pOrWc = &pOrInfo->wc;
+ memset(pOrWc->aStatic, 0, sizeof(pOrWc->aStatic));
+ sqlite3WhereClauseInit(pOrWc, pWInfo);
+ sqlite3WhereSplit(pOrWc, pExpr, TK_OR);
+ sqlite3WhereExprAnalyze(pSrc, pOrWc);
+ if( db->mallocFailed ) return;
+ assert( pOrWc->nTerm>=2 );
+
+ /*
+ ** Compute the set of tables that might satisfy cases 1 or 3.
+ */
+ indexable = ~(Bitmask)0;
+ chngToIN = ~(Bitmask)0;
+ for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0 && indexable; i--, pOrTerm++){
+ if( (pOrTerm->eOperator & WO_SINGLE)==0 ){
+ WhereAndInfo *pAndInfo;
+ assert( (pOrTerm->wtFlags & (TERM_ANDINFO|TERM_ORINFO))==0 );
+ chngToIN = 0;
+ pAndInfo = sqlite3DbMallocRawNN(db, sizeof(*pAndInfo));
+ if( pAndInfo ){
+ WhereClause *pAndWC;
+ WhereTerm *pAndTerm;
+ int j;
+ Bitmask b = 0;
+ pOrTerm->u.pAndInfo = pAndInfo;
+ pOrTerm->wtFlags |= TERM_ANDINFO;
+ pOrTerm->eOperator = WO_AND;
+ pAndWC = &pAndInfo->wc;
+ memset(pAndWC->aStatic, 0, sizeof(pAndWC->aStatic));
+ sqlite3WhereClauseInit(pAndWC, pWC->pWInfo);
+ sqlite3WhereSplit(pAndWC, pOrTerm->pExpr, TK_AND);
+ sqlite3WhereExprAnalyze(pSrc, pAndWC);
+ pAndWC->pOuter = pWC;
+ if( !db->mallocFailed ){
+ for(j=0, pAndTerm=pAndWC->a; j<pAndWC->nTerm; j++, pAndTerm++){
+ assert( pAndTerm->pExpr );
+ if( allowedOp(pAndTerm->pExpr->op)
+ || pAndTerm->eOperator==WO_MATCH
+ ){
+ b |= sqlite3WhereGetMask(&pWInfo->sMaskSet, pAndTerm->leftCursor);
+ }
+ }
+ }
+ indexable &= b;
+ }
+ }else if( pOrTerm->wtFlags & TERM_COPIED ){
+ /* Skip this term for now. We revisit it when we process the
+ ** corresponding TERM_VIRTUAL term */
+ }else{
+ Bitmask b;
+ b = sqlite3WhereGetMask(&pWInfo->sMaskSet, pOrTerm->leftCursor);
+ if( pOrTerm->wtFlags & TERM_VIRTUAL ){
+ WhereTerm *pOther = &pOrWc->a[pOrTerm->iParent];
+ b |= sqlite3WhereGetMask(&pWInfo->sMaskSet, pOther->leftCursor);
+ }
+ indexable &= b;
+ if( (pOrTerm->eOperator & WO_EQ)==0 ){
+ chngToIN = 0;
+ }else{
+ chngToIN &= b;
+ }
+ }
+ }
+
+ /*
+ ** Record the set of tables that satisfy case 3. The set might be
+ ** empty.
+ */
+ pOrInfo->indexable = indexable;
+ pTerm->eOperator = indexable==0 ? 0 : WO_OR;
+
+ /* For a two-way OR, attempt to implementation case 2.
+ */
+ if( indexable && pOrWc->nTerm==2 ){
+ int iOne = 0;
+ WhereTerm *pOne;
+ while( (pOne = whereNthSubterm(&pOrWc->a[0],iOne++))!=0 ){
+ int iTwo = 0;
+ WhereTerm *pTwo;
+ while( (pTwo = whereNthSubterm(&pOrWc->a[1],iTwo++))!=0 ){
+ whereCombineDisjuncts(pSrc, pWC, pOne, pTwo);
+ }
+ }
+ }
+
+ /*
+ ** chngToIN holds a set of tables that *might* satisfy case 1. But
+ ** we have to do some additional checking to see if case 1 really
+ ** is satisfied.
+ **
+ ** chngToIN will hold either 0, 1, or 2 bits. The 0-bit case means
+ ** that there is no possibility of transforming the OR clause into an
+ ** IN operator because one or more terms in the OR clause contain
+ ** something other than == on a column in the single table. The 1-bit
+ ** case means that every term of the OR clause is of the form
+ ** "table.column=expr" for some single table. The one bit that is set
+ ** will correspond to the common table. We still need to check to make
+ ** sure the same column is used on all terms. The 2-bit case is when
+ ** the all terms are of the form "table1.column=table2.column". It
+ ** might be possible to form an IN operator with either table1.column
+ ** or table2.column as the LHS if either is common to every term of
+ ** the OR clause.
+ **
+ ** Note that terms of the form "table.column1=table.column2" (the
+ ** same table on both sizes of the ==) cannot be optimized.
+ */
+ if( chngToIN ){
+ int okToChngToIN = 0; /* True if the conversion to IN is valid */
+ int iColumn = -1; /* Column index on lhs of IN operator */
+ int iCursor = -1; /* Table cursor common to all terms */
+ int j = 0; /* Loop counter */
+
+ /* Search for a table and column that appears on one side or the
+ ** other of the == operator in every subterm. That table and column
+ ** will be recorded in iCursor and iColumn. There might not be any
+ ** such table and column. Set okToChngToIN if an appropriate table
+ ** and column is found but leave okToChngToIN false if not found.
+ */
+ for(j=0; j<2 && !okToChngToIN; j++){
+ pOrTerm = pOrWc->a;
+ for(i=pOrWc->nTerm-1; i>=0; i--, pOrTerm++){
+ assert( pOrTerm->eOperator & WO_EQ );
+ pOrTerm->wtFlags &= ~TERM_OR_OK;
+ if( pOrTerm->leftCursor==iCursor ){
+ /* This is the 2-bit case and we are on the second iteration and
+ ** current term is from the first iteration. So skip this term. */
+ assert( j==1 );
+ continue;
+ }
+ if( (chngToIN & sqlite3WhereGetMask(&pWInfo->sMaskSet,
+ pOrTerm->leftCursor))==0 ){
+ /* This term must be of the form t1.a==t2.b where t2 is in the
+ ** chngToIN set but t1 is not. This term will be either preceded
+ ** or follwed by an inverted copy (t2.b==t1.a). Skip this term
+ ** and use its inversion. */
+ testcase( pOrTerm->wtFlags & TERM_COPIED );
+ testcase( pOrTerm->wtFlags & TERM_VIRTUAL );
+ assert( pOrTerm->wtFlags & (TERM_COPIED|TERM_VIRTUAL) );
+ continue;
+ }
+ iColumn = pOrTerm->u.leftColumn;
+ iCursor = pOrTerm->leftCursor;
+ break;
+ }
+ if( i<0 ){
+ /* No candidate table+column was found. This can only occur
+ ** on the second iteration */
+ assert( j==1 );
+ assert( IsPowerOfTwo(chngToIN) );
+ assert( chngToIN==sqlite3WhereGetMask(&pWInfo->sMaskSet, iCursor) );
+ break;
+ }
+ testcase( j==1 );
+
+ /* We have found a candidate table and column. Check to see if that
+ ** table and column is common to every term in the OR clause */
+ okToChngToIN = 1;
+ for(; i>=0 && okToChngToIN; i--, pOrTerm++){
+ assert( pOrTerm->eOperator & WO_EQ );
+ if( pOrTerm->leftCursor!=iCursor ){
+ pOrTerm->wtFlags &= ~TERM_OR_OK;
+ }else if( pOrTerm->u.leftColumn!=iColumn ){
+ okToChngToIN = 0;
+ }else{
+ int affLeft, affRight;
+ /* If the right-hand side is also a column, then the affinities
+ ** of both right and left sides must be such that no type
+ ** conversions are required on the right. (Ticket #2249)
+ */
+ affRight = sqlite3ExprAffinity(pOrTerm->pExpr->pRight);
+ affLeft = sqlite3ExprAffinity(pOrTerm->pExpr->pLeft);
+ if( affRight!=0 && affRight!=affLeft ){
+ okToChngToIN = 0;
+ }else{
+ pOrTerm->wtFlags |= TERM_OR_OK;
+ }
+ }
+ }
+ }
+
+ /* At this point, okToChngToIN is true if original pTerm satisfies
+ ** case 1. In that case, construct a new virtual term that is
+ ** pTerm converted into an IN operator.
+ */
+ if( okToChngToIN ){
+ Expr *pDup; /* A transient duplicate expression */
+ ExprList *pList = 0; /* The RHS of the IN operator */
+ Expr *pLeft = 0; /* The LHS of the IN operator */
+ Expr *pNew; /* The complete IN operator */
+
+ for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0; i--, pOrTerm++){
+ if( (pOrTerm->wtFlags & TERM_OR_OK)==0 ) continue;
+ assert( pOrTerm->eOperator & WO_EQ );
+ assert( pOrTerm->leftCursor==iCursor );
+ assert( pOrTerm->u.leftColumn==iColumn );
+ pDup = sqlite3ExprDup(db, pOrTerm->pExpr->pRight, 0);
+ pList = sqlite3ExprListAppend(pWInfo->pParse, pList, pDup);
+ pLeft = pOrTerm->pExpr->pLeft;
+ }
+ assert( pLeft!=0 );
+ pDup = sqlite3ExprDup(db, pLeft, 0);
+ pNew = sqlite3PExpr(pParse, TK_IN, pDup, 0);
+ if( pNew ){
+ int idxNew;
+ transferJoinMarkings(pNew, pExpr);
+ assert( !ExprHasProperty(pNew, EP_xIsSelect) );
+ pNew->x.pList = pList;
+ idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
+ testcase( idxNew==0 );
+ exprAnalyze(pSrc, pWC, idxNew);
+ pTerm = &pWC->a[idxTerm];
+ markTermAsChild(pWC, idxNew, idxTerm);
+ }else{
+ sqlite3ExprListDelete(db, pList);
+ }
+ pTerm->eOperator = WO_NOOP; /* case 1 trumps case 3 */
+ }
+ }
+}
+#endif /* !SQLITE_OMIT_OR_OPTIMIZATION && !SQLITE_OMIT_SUBQUERY */
+
+/*
+** We already know that pExpr is a binary operator where both operands are
+** column references. This routine checks to see if pExpr is an equivalence
+** relation:
+** 1. The SQLITE_Transitive optimization must be enabled
+** 2. Must be either an == or an IS operator
+** 3. Not originating in the ON clause of an OUTER JOIN
+** 4. The affinities of A and B must be compatible
+** 5a. Both operands use the same collating sequence OR
+** 5b. The overall collating sequence is BINARY
+** If this routine returns TRUE, that means that the RHS can be substituted
+** for the LHS anyplace else in the WHERE clause where the LHS column occurs.
+** This is an optimization. No harm comes from returning 0. But if 1 is
+** returned when it should not be, then incorrect answers might result.
+*/
+static int termIsEquivalence(Parse *pParse, Expr *pExpr){
+ char aff1, aff2;
+ CollSeq *pColl;
+ const char *zColl1, *zColl2;
+ if( !OptimizationEnabled(pParse->db, SQLITE_Transitive) ) return 0;
+ if( pExpr->op!=TK_EQ && pExpr->op!=TK_IS ) return 0;
+ if( ExprHasProperty(pExpr, EP_FromJoin) ) return 0;
+ aff1 = sqlite3ExprAffinity(pExpr->pLeft);
+ aff2 = sqlite3ExprAffinity(pExpr->pRight);
+ if( aff1!=aff2
+ && (!sqlite3IsNumericAffinity(aff1) || !sqlite3IsNumericAffinity(aff2))
+ ){
+ return 0;
+ }
+ pColl = sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft, pExpr->pRight);
+ if( pColl==0 || sqlite3StrICmp(pColl->zName, "BINARY")==0 ) return 1;
+ pColl = sqlite3ExprCollSeq(pParse, pExpr->pLeft);
+ zColl1 = pColl ? pColl->zName : 0;
+ pColl = sqlite3ExprCollSeq(pParse, pExpr->pRight);
+ zColl2 = pColl ? pColl->zName : 0;
+ return sqlite3_stricmp(zColl1, zColl2)==0;
+}
+
+/*
+** Recursively walk the expressions of a SELECT statement and generate
+** a bitmask indicating which tables are used in that expression
+** tree.
+*/
+static Bitmask exprSelectUsage(WhereMaskSet *pMaskSet, Select *pS){
+ Bitmask mask = 0;
+ while( pS ){
+ SrcList *pSrc = pS->pSrc;
+ mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pEList);
+ mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pGroupBy);
+ mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pOrderBy);
+ mask |= sqlite3WhereExprUsage(pMaskSet, pS->pWhere);
+ mask |= sqlite3WhereExprUsage(pMaskSet, pS->pHaving);
+ if( ALWAYS(pSrc!=0) ){
+ int i;
+ for(i=0; i<pSrc->nSrc; i++){
+ mask |= exprSelectUsage(pMaskSet, pSrc->a[i].pSelect);
+ mask |= sqlite3WhereExprUsage(pMaskSet, pSrc->a[i].pOn);
+ }
+ }
+ pS = pS->pPrior;
+ }
+ return mask;
+}
+
+/*
+** Expression pExpr is one operand of a comparison operator that might
+** be useful for indexing. This routine checks to see if pExpr appears
+** in any index. Return TRUE (1) if pExpr is an indexed term and return
+** FALSE (0) if not. If TRUE is returned, also set *piCur to the cursor
+** number of the table that is indexed and *piColumn to the column number
+** of the column that is indexed, or XN_EXPR (-2) if an expression is being
+** indexed.
+**
+** If pExpr is a TK_COLUMN column reference, then this routine always returns
+** true even if that particular column is not indexed, because the column
+** might be added to an automatic index later.
+*/
+static int exprMightBeIndexed(
+ SrcList *pFrom, /* The FROM clause */
+ int op, /* The specific comparison operator */
+ Bitmask mPrereq, /* Bitmask of FROM clause terms referenced by pExpr */
+ Expr *pExpr, /* An operand of a comparison operator */
+ int *piCur, /* Write the referenced table cursor number here */
+ int *piColumn /* Write the referenced table column number here */
+){
+ Index *pIdx;
+ int i;
+ int iCur;
+
+ /* If this expression is a vector to the left or right of a
+ ** inequality constraint (>, <, >= or <=), perform the processing
+ ** on the first element of the vector. */
+ assert( TK_GT+1==TK_LE && TK_GT+2==TK_LT && TK_GT+3==TK_GE );
+ assert( TK_IS<TK_GE && TK_ISNULL<TK_GE && TK_IN<TK_GE );
+ assert( op<=TK_GE );
+ if( pExpr->op==TK_VECTOR && (op>=TK_GT && ALWAYS(op<=TK_GE)) ){
+ pExpr = pExpr->x.pList->a[0].pExpr;
+ }
+
+ if( pExpr->op==TK_COLUMN ){
+ *piCur = pExpr->iTable;
+ *piColumn = pExpr->iColumn;
+ return 1;
+ }
+ if( mPrereq==0 ) return 0; /* No table references */
+ if( (mPrereq&(mPrereq-1))!=0 ) return 0; /* Refs more than one table */
+ for(i=0; mPrereq>1; i++, mPrereq>>=1){}
+ iCur = pFrom->a[i].iCursor;
+ for(pIdx=pFrom->a[i].pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+ if( pIdx->aColExpr==0 ) continue;
+ for(i=0; i<pIdx->nKeyCol; i++){
+ if( pIdx->aiColumn[i]!=XN_EXPR ) continue;
+ if( sqlite3ExprCompare(pExpr, pIdx->aColExpr->a[i].pExpr, iCur)==0 ){
+ *piCur = iCur;
+ *piColumn = XN_EXPR;
+ return 1;
+ }
+ }
+ }
+ return 0;
+}
+
+/*
+** The input to this routine is an WhereTerm structure with only the
+** "pExpr" field filled in. The job of this routine is to analyze the
+** subexpression and populate all the other fields of the WhereTerm
+** structure.
+**
+** If the expression is of the form "<expr> <op> X" it gets commuted
+** to the standard form of "X <op> <expr>".
+**
+** If the expression is of the form "X <op> Y" where both X and Y are
+** columns, then the original expression is unchanged and a new virtual
+** term of the form "Y <op> X" is added to the WHERE clause and
+** analyzed separately. The original term is marked with TERM_COPIED
+** and the new term is marked with TERM_DYNAMIC (because it's pExpr
+** needs to be freed with the WhereClause) and TERM_VIRTUAL (because it
+** is a commuted copy of a prior term.) The original term has nChild=1
+** and the copy has idxParent set to the index of the original term.
+*/
+static void exprAnalyze(
+ SrcList *pSrc, /* the FROM clause */
+ WhereClause *pWC, /* the WHERE clause */
+ int idxTerm /* Index of the term to be analyzed */
+){
+ WhereInfo *pWInfo = pWC->pWInfo; /* WHERE clause processing context */
+ WhereTerm *pTerm; /* The term to be analyzed */
+ WhereMaskSet *pMaskSet; /* Set of table index masks */
+ Expr *pExpr; /* The expression to be analyzed */
+ Bitmask prereqLeft; /* Prerequesites of the pExpr->pLeft */
+ Bitmask prereqAll; /* Prerequesites of pExpr */
+ Bitmask extraRight = 0; /* Extra dependencies on LEFT JOIN */
+ Expr *pStr1 = 0; /* RHS of LIKE/GLOB operator */
+ int isComplete = 0; /* RHS of LIKE/GLOB ends with wildcard */
+ int noCase = 0; /* uppercase equivalent to lowercase */
+ int op; /* Top-level operator. pExpr->op */
+ Parse *pParse = pWInfo->pParse; /* Parsing context */
+ sqlite3 *db = pParse->db; /* Database connection */
+ unsigned char eOp2; /* op2 value for LIKE/REGEXP/GLOB */
+ int nLeft; /* Number of elements on left side vector */
+
+ if( db->mallocFailed ){
+ return;
+ }
+ pTerm = &pWC->a[idxTerm];
+ pMaskSet = &pWInfo->sMaskSet;
+ pExpr = pTerm->pExpr;
+ assert( pExpr->op!=TK_AS && pExpr->op!=TK_COLLATE );
+ prereqLeft = sqlite3WhereExprUsage(pMaskSet, pExpr->pLeft);
+ op = pExpr->op;
+ if( op==TK_IN ){
+ assert( pExpr->pRight==0 );
+ if( sqlite3ExprCheckIN(pParse, pExpr) ) return;
+ if( ExprHasProperty(pExpr, EP_xIsSelect) ){
+ pTerm->prereqRight = exprSelectUsage(pMaskSet, pExpr->x.pSelect);
+ }else{
+ pTerm->prereqRight = sqlite3WhereExprListUsage(pMaskSet, pExpr->x.pList);
+ }
+ }else if( op==TK_ISNULL ){
+ pTerm->prereqRight = 0;
+ }else{
+ pTerm->prereqRight = sqlite3WhereExprUsage(pMaskSet, pExpr->pRight);
+ }
+ prereqAll = sqlite3WhereExprUsage(pMaskSet, pExpr);
+ if( ExprHasProperty(pExpr, EP_FromJoin) ){
+ Bitmask x = sqlite3WhereGetMask(pMaskSet, pExpr->iRightJoinTable);
+ prereqAll |= x;
+ extraRight = x-1; /* ON clause terms may not be used with an index
+ ** on left table of a LEFT JOIN. Ticket #3015 */
+ if( (prereqAll>>1)>=x ){
+ sqlite3ErrorMsg(pParse, "ON clause references tables to its right");
+ return;
+ }
+ }
+ pTerm->prereqAll = prereqAll;
+ pTerm->leftCursor = -1;
+ pTerm->iParent = -1;
+ pTerm->eOperator = 0;
+ if( allowedOp(op) ){
+ int iCur, iColumn;
+ Expr *pLeft = sqlite3ExprSkipCollate(pExpr->pLeft);
+ Expr *pRight = sqlite3ExprSkipCollate(pExpr->pRight);
+ u16 opMask = (pTerm->prereqRight & prereqLeft)==0 ? WO_ALL : WO_EQUIV;
+
+ if( pTerm->iField>0 ){
+ assert( op==TK_IN );
+ assert( pLeft->op==TK_VECTOR );
+ pLeft = pLeft->x.pList->a[pTerm->iField-1].pExpr;
+ }
+
+ if( exprMightBeIndexed(pSrc, op, prereqLeft, pLeft, &iCur, &iColumn) ){
+ pTerm->leftCursor = iCur;
+ pTerm->u.leftColumn = iColumn;
+ pTerm->eOperator = operatorMask(op) & opMask;
+ }
+ if( op==TK_IS ) pTerm->wtFlags |= TERM_IS;
+ if( pRight
+ && exprMightBeIndexed(pSrc, op, pTerm->prereqRight, pRight, &iCur,&iColumn)
+ ){
+ WhereTerm *pNew;
+ Expr *pDup;
+ u16 eExtraOp = 0; /* Extra bits for pNew->eOperator */
+ assert( pTerm->iField==0 );
+ if( pTerm->leftCursor>=0 ){
+ int idxNew;
+ pDup = sqlite3ExprDup(db, pExpr, 0);
+ if( db->mallocFailed ){
+ sqlite3ExprDelete(db, pDup);
+ return;
+ }
+ idxNew = whereClauseInsert(pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC);
+ if( idxNew==0 ) return;
+ pNew = &pWC->a[idxNew];
+ markTermAsChild(pWC, idxNew, idxTerm);
+ if( op==TK_IS ) pNew->wtFlags |= TERM_IS;
+ pTerm = &pWC->a[idxTerm];
+ pTerm->wtFlags |= TERM_COPIED;
+
+ if( termIsEquivalence(pParse, pDup) ){
+ pTerm->eOperator |= WO_EQUIV;
+ eExtraOp = WO_EQUIV;
+ }
+ }else{
+ pDup = pExpr;
+ pNew = pTerm;
+ }
+ exprCommute(pParse, pDup);
+ pNew->leftCursor = iCur;
+ pNew->u.leftColumn = iColumn;
+ testcase( (prereqLeft | extraRight) != prereqLeft );
+ pNew->prereqRight = prereqLeft | extraRight;
+ pNew->prereqAll = prereqAll;
+ pNew->eOperator = (operatorMask(pDup->op) + eExtraOp) & opMask;
+ }
+ }
+
+#ifndef SQLITE_OMIT_BETWEEN_OPTIMIZATION
+ /* If a term is the BETWEEN operator, create two new virtual terms
+ ** that define the range that the BETWEEN implements. For example:
+ **
+ ** a BETWEEN b AND c
+ **
+ ** is converted into:
+ **
+ ** (a BETWEEN b AND c) AND (a>=b) AND (a<=c)
+ **
+ ** The two new terms are added onto the end of the WhereClause object.
+ ** The new terms are "dynamic" and are children of the original BETWEEN
+ ** term. That means that if the BETWEEN term is coded, the children are
+ ** skipped. Or, if the children are satisfied by an index, the original
+ ** BETWEEN term is skipped.
+ */
+ else if( pExpr->op==TK_BETWEEN && pWC->op==TK_AND ){
+ ExprList *pList = pExpr->x.pList;
+ int i;
+ static const u8 ops[] = {TK_GE, TK_LE};
+ assert( pList!=0 );
+ assert( pList->nExpr==2 );
+ for(i=0; i<2; i++){
+ Expr *pNewExpr;
+ int idxNew;
+ pNewExpr = sqlite3PExpr(pParse, ops[i],
+ sqlite3ExprDup(db, pExpr->pLeft, 0),
+ sqlite3ExprDup(db, pList->a[i].pExpr, 0));
+ transferJoinMarkings(pNewExpr, pExpr);
+ idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
+ testcase( idxNew==0 );
+ exprAnalyze(pSrc, pWC, idxNew);
+ pTerm = &pWC->a[idxTerm];
+ markTermAsChild(pWC, idxNew, idxTerm);
+ }
+ }
+#endif /* SQLITE_OMIT_BETWEEN_OPTIMIZATION */
+
+#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
+ /* Analyze a term that is composed of two or more subterms connected by
+ ** an OR operator.
+ */
+ else if( pExpr->op==TK_OR ){
+ assert( pWC->op==TK_AND );
+ exprAnalyzeOrTerm(pSrc, pWC, idxTerm);
+ pTerm = &pWC->a[idxTerm];
+ }
+#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
+
+#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
+ /* Add constraints to reduce the search space on a LIKE or GLOB
+ ** operator.
+ **
+ ** A like pattern of the form "x LIKE 'aBc%'" is changed into constraints
+ **
+ ** x>='ABC' AND x<'abd' AND x LIKE 'aBc%'
+ **
+ ** The last character of the prefix "abc" is incremented to form the
+ ** termination condition "abd". If case is not significant (the default
+ ** for LIKE) then the lower-bound is made all uppercase and the upper-
+ ** bound is made all lowercase so that the bounds also work when comparing
+ ** BLOBs.
+ */
+ if( pWC->op==TK_AND
+ && isLikeOrGlob(pParse, pExpr, &pStr1, &isComplete, &noCase)
+ ){
+ Expr *pLeft; /* LHS of LIKE/GLOB operator */
+ Expr *pStr2; /* Copy of pStr1 - RHS of LIKE/GLOB operator */
+ Expr *pNewExpr1;
+ Expr *pNewExpr2;
+ int idxNew1;
+ int idxNew2;
+ const char *zCollSeqName; /* Name of collating sequence */
+ const u16 wtFlags = TERM_LIKEOPT | TERM_VIRTUAL | TERM_DYNAMIC;
+
+ pLeft = pExpr->x.pList->a[1].pExpr;
+ pStr2 = sqlite3ExprDup(db, pStr1, 0);
+
+ /* Convert the lower bound to upper-case and the upper bound to
+ ** lower-case (upper-case is less than lower-case in ASCII) so that
+ ** the range constraints also work for BLOBs
+ */
+ if( noCase && !pParse->db->mallocFailed ){
+ int i;
+ char c;
+ pTerm->wtFlags |= TERM_LIKE;
+ for(i=0; (c = pStr1->u.zToken[i])!=0; i++){
+ pStr1->u.zToken[i] = sqlite3Toupper(c);
+ pStr2->u.zToken[i] = sqlite3Tolower(c);
+ }
+ }
+
+ if( !db->mallocFailed ){
+ u8 c, *pC; /* Last character before the first wildcard */
+ pC = (u8*)&pStr2->u.zToken[sqlite3Strlen30(pStr2->u.zToken)-1];
+ c = *pC;
+ if( noCase ){
+ /* The point is to increment the last character before the first
+ ** wildcard. But if we increment '@', that will push it into the
+ ** alphabetic range where case conversions will mess up the
+ ** inequality. To avoid this, make sure to also run the full
+ ** LIKE on all candidate expressions by clearing the isComplete flag
+ */
+ if( c=='A'-1 ) isComplete = 0;
+ c = sqlite3UpperToLower[c];
+ }
+ *pC = c + 1;
+ }
+ zCollSeqName = noCase ? "NOCASE" : "BINARY";
+ pNewExpr1 = sqlite3ExprDup(db, pLeft, 0);
+ pNewExpr1 = sqlite3PExpr(pParse, TK_GE,
+ sqlite3ExprAddCollateString(pParse,pNewExpr1,zCollSeqName),
+ pStr1);
+ transferJoinMarkings(pNewExpr1, pExpr);
+ idxNew1 = whereClauseInsert(pWC, pNewExpr1, wtFlags);
+ testcase( idxNew1==0 );
+ exprAnalyze(pSrc, pWC, idxNew1);
+ pNewExpr2 = sqlite3ExprDup(db, pLeft, 0);
+ pNewExpr2 = sqlite3PExpr(pParse, TK_LT,
+ sqlite3ExprAddCollateString(pParse,pNewExpr2,zCollSeqName),
+ pStr2);
+ transferJoinMarkings(pNewExpr2, pExpr);
+ idxNew2 = whereClauseInsert(pWC, pNewExpr2, wtFlags);
+ testcase( idxNew2==0 );
+ exprAnalyze(pSrc, pWC, idxNew2);
+ pTerm = &pWC->a[idxTerm];
+ if( isComplete ){
+ markTermAsChild(pWC, idxNew1, idxTerm);
+ markTermAsChild(pWC, idxNew2, idxTerm);
+ }
+ }
+#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+ /* Add a WO_MATCH auxiliary term to the constraint set if the
+ ** current expression is of the form: column MATCH expr.
+ ** This information is used by the xBestIndex methods of
+ ** virtual tables. The native query optimizer does not attempt
+ ** to do anything with MATCH functions.
+ */
+ if( pWC->op==TK_AND && isMatchOfColumn(pExpr, &eOp2) ){
+ int idxNew;
+ Expr *pRight, *pLeft;
+ WhereTerm *pNewTerm;
+ Bitmask prereqColumn, prereqExpr;
+
+ pRight = pExpr->x.pList->a[0].pExpr;
+ pLeft = pExpr->x.pList->a[1].pExpr;
+ prereqExpr = sqlite3WhereExprUsage(pMaskSet, pRight);
+ prereqColumn = sqlite3WhereExprUsage(pMaskSet, pLeft);
+ if( (prereqExpr & prereqColumn)==0 ){
+ Expr *pNewExpr;
+ pNewExpr = sqlite3PExpr(pParse, TK_MATCH,
+ 0, sqlite3ExprDup(db, pRight, 0));
+ idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
+ testcase( idxNew==0 );
+ pNewTerm = &pWC->a[idxNew];
+ pNewTerm->prereqRight = prereqExpr;
+ pNewTerm->leftCursor = pLeft->iTable;
+ pNewTerm->u.leftColumn = pLeft->iColumn;
+ pNewTerm->eOperator = WO_MATCH;
+ pNewTerm->eMatchOp = eOp2;
+ markTermAsChild(pWC, idxNew, idxTerm);
+ pTerm = &pWC->a[idxTerm];
+ pTerm->wtFlags |= TERM_COPIED;
+ pNewTerm->prereqAll = pTerm->prereqAll;
+ }
+ }
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+ /* If there is a vector == or IS term - e.g. "(a, b) == (?, ?)" - create
+ ** new terms for each component comparison - "a = ?" and "b = ?". The
+ ** new terms completely replace the original vector comparison, which is
+ ** no longer used.
+ **
+ ** This is only required if at least one side of the comparison operation
+ ** is not a sub-select. */
+ if( pWC->op==TK_AND
+ && (pExpr->op==TK_EQ || pExpr->op==TK_IS)
+ && (nLeft = sqlite3ExprVectorSize(pExpr->pLeft))>1
+ && sqlite3ExprVectorSize(pExpr->pRight)==nLeft
+ && ( (pExpr->pLeft->flags & EP_xIsSelect)==0
+ || (pExpr->pRight->flags & EP_xIsSelect)==0)
+ ){
+ int i;
+ for(i=0; i<nLeft; i++){
+ int idxNew;
+ Expr *pNew;
+ Expr *pLeft = sqlite3ExprForVectorField(pParse, pExpr->pLeft, i);
+ Expr *pRight = sqlite3ExprForVectorField(pParse, pExpr->pRight, i);
+
+ pNew = sqlite3PExpr(pParse, pExpr->op, pLeft, pRight);
+ transferJoinMarkings(pNew, pExpr);
+ idxNew = whereClauseInsert(pWC, pNew, TERM_DYNAMIC);
+ exprAnalyze(pSrc, pWC, idxNew);
+ }
+ pTerm = &pWC->a[idxTerm];
+ pTerm->wtFlags = TERM_CODED|TERM_VIRTUAL; /* Disable the original */
+ pTerm->eOperator = 0;
+ }
+
+ /* If there is a vector IN term - e.g. "(a, b) IN (SELECT ...)" - create
+ ** a virtual term for each vector component. The expression object
+ ** used by each such virtual term is pExpr (the full vector IN(...)
+ ** expression). The WhereTerm.iField variable identifies the index within
+ ** the vector on the LHS that the virtual term represents.
+ **
+ ** This only works if the RHS is a simple SELECT, not a compound
+ */
+ if( pWC->op==TK_AND && pExpr->op==TK_IN && pTerm->iField==0
+ && pExpr->pLeft->op==TK_VECTOR
+ && pExpr->x.pSelect->pPrior==0
+ ){
+ int i;
+ for(i=0; i<sqlite3ExprVectorSize(pExpr->pLeft); i++){
+ int idxNew;
+ idxNew = whereClauseInsert(pWC, pExpr, TERM_VIRTUAL);
+ pWC->a[idxNew].iField = i+1;
+ exprAnalyze(pSrc, pWC, idxNew);
+ markTermAsChild(pWC, idxNew, idxTerm);
+ }
+ }
+
+#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
+ /* When sqlite_stat3 histogram data is available an operator of the
+ ** form "x IS NOT NULL" can sometimes be evaluated more efficiently
+ ** as "x>NULL" if x is not an INTEGER PRIMARY KEY. So construct a
+ ** virtual term of that form.
+ **
+ ** Note that the virtual term must be tagged with TERM_VNULL.
+ */
+ if( pExpr->op==TK_NOTNULL
+ && pExpr->pLeft->op==TK_COLUMN
+ && pExpr->pLeft->iColumn>=0
+ && OptimizationEnabled(db, SQLITE_Stat34)
+ ){
+ Expr *pNewExpr;
+ Expr *pLeft = pExpr->pLeft;
+ int idxNew;
+ WhereTerm *pNewTerm;
+
+ pNewExpr = sqlite3PExpr(pParse, TK_GT,
+ sqlite3ExprDup(db, pLeft, 0),
+ sqlite3ExprAlloc(db, TK_NULL, 0, 0));
+
+ idxNew = whereClauseInsert(pWC, pNewExpr,
+ TERM_VIRTUAL|TERM_DYNAMIC|TERM_VNULL);
+ if( idxNew ){
+ pNewTerm = &pWC->a[idxNew];
+ pNewTerm->prereqRight = 0;
+ pNewTerm->leftCursor = pLeft->iTable;
+ pNewTerm->u.leftColumn = pLeft->iColumn;
+ pNewTerm->eOperator = WO_GT;
+ markTermAsChild(pWC, idxNew, idxTerm);
+ pTerm = &pWC->a[idxTerm];
+ pTerm->wtFlags |= TERM_COPIED;
+ pNewTerm->prereqAll = pTerm->prereqAll;
+ }
+ }
+#endif /* SQLITE_ENABLE_STAT3_OR_STAT4 */
+
+ /* Prevent ON clause terms of a LEFT JOIN from being used to drive
+ ** an index for tables to the left of the join.
+ */
+ testcase( pTerm!=&pWC->a[idxTerm] );
+ pTerm = &pWC->a[idxTerm];
+ pTerm->prereqRight |= extraRight;
+}
+
+/***************************************************************************
+** Routines with file scope above. Interface to the rest of the where.c
+** subsystem follows.
+***************************************************************************/
+
+/*
+** This routine identifies subexpressions in the WHERE clause where
+** each subexpression is separated by the AND operator or some other
+** operator specified in the op parameter. The WhereClause structure
+** is filled with pointers to subexpressions. For example:
+**
+** WHERE a=='hello' AND coalesce(b,11)<10 AND (c+12!=d OR c==22)
+** \________/ \_______________/ \________________/
+** slot[0] slot[1] slot[2]
+**
+** The original WHERE clause in pExpr is unaltered. All this routine
+** does is make slot[] entries point to substructure within pExpr.
+**
+** In the previous sentence and in the diagram, "slot[]" refers to
+** the WhereClause.a[] array. The slot[] array grows as needed to contain
+** all terms of the WHERE clause.
+*/
+void sqlite3WhereSplit(WhereClause *pWC, Expr *pExpr, u8 op){
+ Expr *pE2 = sqlite3ExprSkipCollate(pExpr);
+ pWC->op = op;
+ if( pE2==0 ) return;
+ if( pE2->op!=op ){
+ whereClauseInsert(pWC, pExpr, 0);
+ }else{
+ sqlite3WhereSplit(pWC, pE2->pLeft, op);
+ sqlite3WhereSplit(pWC, pE2->pRight, op);
+ }
+}
+
+/*
+** Initialize a preallocated WhereClause structure.
+*/
+void sqlite3WhereClauseInit(
+ WhereClause *pWC, /* The WhereClause to be initialized */
+ WhereInfo *pWInfo /* The WHERE processing context */
+){
+ pWC->pWInfo = pWInfo;
+ pWC->pOuter = 0;
+ pWC->nTerm = 0;
+ pWC->nSlot = ArraySize(pWC->aStatic);
+ pWC->a = pWC->aStatic;
+}
+
+/*
+** Deallocate a WhereClause structure. The WhereClause structure
+** itself is not freed. This routine is the inverse of
+** sqlite3WhereClauseInit().
+*/
+void sqlite3WhereClauseClear(WhereClause *pWC){
+ int i;
+ WhereTerm *a;
+ sqlite3 *db = pWC->pWInfo->pParse->db;
+ for(i=pWC->nTerm-1, a=pWC->a; i>=0; i--, a++){
+ if( a->wtFlags & TERM_DYNAMIC ){
+ sqlite3ExprDelete(db, a->pExpr);
+ }
+ if( a->wtFlags & TERM_ORINFO ){
+ whereOrInfoDelete(db, a->u.pOrInfo);
+ }else if( a->wtFlags & TERM_ANDINFO ){
+ whereAndInfoDelete(db, a->u.pAndInfo);
+ }
+ }
+ if( pWC->a!=pWC->aStatic ){
+ sqlite3DbFree(db, pWC->a);
+ }
+}
+
+
+/*
+** These routines walk (recursively) an expression tree and generate
+** a bitmask indicating which tables are used in that expression
+** tree.
+*/
+Bitmask sqlite3WhereExprUsage(WhereMaskSet *pMaskSet, Expr *p){
+ Bitmask mask;
+ if( p==0 ) return 0;
+ if( p->op==TK_COLUMN ){
+ mask = sqlite3WhereGetMask(pMaskSet, p->iTable);
+ return mask;
+ }
+ assert( !ExprHasProperty(p, EP_TokenOnly) );
+ mask = p->pRight ? sqlite3WhereExprUsage(pMaskSet, p->pRight) : 0;
+ if( p->pLeft ) mask |= sqlite3WhereExprUsage(pMaskSet, p->pLeft);
+ if( ExprHasProperty(p, EP_xIsSelect) ){
+ mask |= exprSelectUsage(pMaskSet, p->x.pSelect);
+ }else if( p->x.pList ){
+ mask |= sqlite3WhereExprListUsage(pMaskSet, p->x.pList);
+ }
+ return mask;
+}
+Bitmask sqlite3WhereExprListUsage(WhereMaskSet *pMaskSet, ExprList *pList){
+ int i;
+ Bitmask mask = 0;
+ if( pList ){
+ for(i=0; i<pList->nExpr; i++){
+ mask |= sqlite3WhereExprUsage(pMaskSet, pList->a[i].pExpr);
+ }
+ }
+ return mask;
+}
+
+
+/*
+** Call exprAnalyze on all terms in a WHERE clause.
+**
+** Note that exprAnalyze() might add new virtual terms onto the
+** end of the WHERE clause. We do not want to analyze these new
+** virtual terms, so start analyzing at the end and work forward
+** so that the added virtual terms are never processed.
+*/
+void sqlite3WhereExprAnalyze(
+ SrcList *pTabList, /* the FROM clause */
+ WhereClause *pWC /* the WHERE clause to be analyzed */
+){
+ int i;
+ for(i=pWC->nTerm-1; i>=0; i--){
+ exprAnalyze(pTabList, pWC, i);
+ }
+}
+
+/*
+** For table-valued-functions, transform the function arguments into
+** new WHERE clause terms.
+**
+** Each function argument translates into an equality constraint against
+** a HIDDEN column in the table.
+*/
+void sqlite3WhereTabFuncArgs(
+ Parse *pParse, /* Parsing context */
+ struct SrcList_item *pItem, /* The FROM clause term to process */
+ WhereClause *pWC /* Xfer function arguments to here */
+){
+ Table *pTab;
+ int j, k;
+ ExprList *pArgs;
+ Expr *pColRef;
+ Expr *pTerm;
+ if( pItem->fg.isTabFunc==0 ) return;
+ pTab = pItem->pTab;
+ assert( pTab!=0 );
+ pArgs = pItem->u1.pFuncArg;
+ if( pArgs==0 ) return;
+ for(j=k=0; j<pArgs->nExpr; j++){
+ while( k<pTab->nCol && (pTab->aCol[k].colFlags & COLFLAG_HIDDEN)==0 ){k++;}
+ if( k>=pTab->nCol ){
+ sqlite3ErrorMsg(pParse, "too many arguments on %s() - max %d",
+ pTab->zName, j);
+ return;
+ }
+ pColRef = sqlite3ExprAlloc(pParse->db, TK_COLUMN, 0, 0);
+ if( pColRef==0 ) return;
+ pColRef->iTable = pItem->iCursor;
+ pColRef->iColumn = k++;
+ pColRef->pTab = pTab;
+ pTerm = sqlite3PExpr(pParse, TK_EQ, pColRef,
+ sqlite3ExprDup(pParse->db, pArgs->a[j].pExpr, 0));
+ whereClauseInsert(pWC, pTerm, TERM_DYNAMIC);
+ }
+}
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