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/* ** 2001 September 15 ** ** 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 contains routines used for analyzing expressions and ** for generating VDBE code that evaluates expressions in SQLite. ** ** $Id: expr.c,v 1.228 2005/09/16 02:38:10 drh Exp $ */ #include "sqliteInt.h" #include <ctype.h> /* ** Return the 'affinity' of the expression pExpr if any. ** ** If pExpr is a column, a reference to a column via an 'AS' alias, ** or a sub-select with a column as the return value, then the ** affinity of that column is returned. Otherwise, 0x00 is returned, ** indicating no affinity for the expression. ** ** i.e. the WHERE clause expresssions in the following statements all ** have an affinity: ** ** CREATE TABLE t1(a); ** SELECT * FROM t1 WHERE a; ** SELECT a AS b FROM t1 WHERE b; ** SELECT * FROM t1 WHERE (select a from t1); */ char sqlite3ExprAffinity(Expr *pExpr){ int op = pExpr->op; if( op==TK_AS ){ return sqlite3ExprAffinity(pExpr->pLeft); } if( op==TK_SELECT ){ return sqlite3ExprAffinity(pExpr->pSelect->pEList->a[0].pExpr); } #ifndef SQLITE_OMIT_CAST if( op==TK_CAST ){ return sqlite3AffinityType(&pExpr->token); } #endif return pExpr->affinity; } /* ** Return the default collation sequence for the expression pExpr. If ** there is no default collation type, return 0. */ CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr){ CollSeq *pColl = 0; if( pExpr ){ pColl = pExpr->pColl; if( (pExpr->op==TK_AS || pExpr->op==TK_CAST) && !pColl ){ return sqlite3ExprCollSeq(pParse, pExpr->pLeft); } } if( sqlite3CheckCollSeq(pParse, pColl) ){ pColl = 0; } return pColl; } /* ** pExpr is an operand of a comparison operator. aff2 is the ** type affinity of the other operand. This routine returns the ** type affinity that should be used for the comparison operator. */ char sqlite3CompareAffinity(Expr *pExpr, char aff2){ char aff1 = sqlite3ExprAffinity(pExpr); if( aff1 && aff2 ){ /* Both sides of the comparison are columns. If one has numeric or ** integer affinity, use that. Otherwise use no affinity. */ if( aff1==SQLITE_AFF_INTEGER || aff2==SQLITE_AFF_INTEGER ){ return SQLITE_AFF_INTEGER; }else if( aff1==SQLITE_AFF_NUMERIC || aff2==SQLITE_AFF_NUMERIC ){ return SQLITE_AFF_NUMERIC; }else{ return SQLITE_AFF_NONE; } }else if( !aff1 && !aff2 ){ /* Neither side of the comparison is a column. Compare the ** results directly. */ /* return SQLITE_AFF_NUMERIC; // Ticket #805 */ return SQLITE_AFF_NONE; }else{ /* One side is a column, the other is not. Use the columns affinity. */ assert( aff1==0 || aff2==0 ); return (aff1 + aff2); } } /* ** pExpr is a comparison operator. Return the type affinity that should ** be applied to both operands prior to doing the comparison. */ static char comparisonAffinity(Expr *pExpr){ char aff; assert( pExpr->op==TK_EQ || pExpr->op==TK_IN || pExpr->op==TK_LT || pExpr->op==TK_GT || pExpr->op==TK_GE || pExpr->op==TK_LE || pExpr->op==TK_NE ); assert( pExpr->pLeft ); aff = sqlite3ExprAffinity(pExpr->pLeft); if( pExpr->pRight ){ aff = sqlite3CompareAffinity(pExpr->pRight, aff); } else if( pExpr->pSelect ){ aff = sqlite3CompareAffinity(pExpr->pSelect->pEList->a[0].pExpr, aff); } else if( !aff ){ aff = SQLITE_AFF_NUMERIC; } return aff; } /* ** pExpr is a comparison expression, eg. '=', '<', IN(...) etc. ** idx_affinity is the affinity of an indexed column. Return true ** if the index with affinity idx_affinity may be used to implement ** the comparison in pExpr. */ int sqlite3IndexAffinityOk(Expr *pExpr, char idx_affinity){ char aff = comparisonAffinity(pExpr); return (aff==SQLITE_AFF_NONE) || (aff==SQLITE_AFF_NUMERIC && idx_affinity==SQLITE_AFF_INTEGER) || (aff==SQLITE_AFF_INTEGER && idx_affinity==SQLITE_AFF_NUMERIC) || (aff==idx_affinity); } /* ** Return the P1 value that should be used for a binary comparison ** opcode (OP_Eq, OP_Ge etc.) used to compare pExpr1 and pExpr2. ** If jumpIfNull is true, then set the low byte of the returned ** P1 value to tell the opcode to jump if either expression ** evaluates to NULL. */ static int binaryCompareP1(Expr *pExpr1, Expr *pExpr2, int jumpIfNull){ char aff = sqlite3ExprAffinity(pExpr2); return ((int)sqlite3CompareAffinity(pExpr1, aff))+(jumpIfNull?0x100:0); } /* ** Return a pointer to the collation sequence that should be used by ** a binary comparison operator comparing pLeft and pRight. ** ** If the left hand expression has a collating sequence type, then it is ** used. Otherwise the collation sequence for the right hand expression ** is used, or the default (BINARY) if neither expression has a collating ** type. */ static CollSeq* binaryCompareCollSeq(Parse *pParse, Expr *pLeft, Expr *pRight){ CollSeq *pColl = sqlite3ExprCollSeq(pParse, pLeft); if( !pColl ){ pColl = sqlite3ExprCollSeq(pParse, pRight); } return pColl; } /* ** Generate code for a comparison operator. */ static int codeCompare( Parse *pParse, /* The parsing (and code generating) context */ Expr *pLeft, /* The left operand */ Expr *pRight, /* The right operand */ int opcode, /* The comparison opcode */ int dest, /* Jump here if true. */ int jumpIfNull /* If true, jump if either operand is NULL */ ){ int p1 = binaryCompareP1(pLeft, pRight, jumpIfNull); CollSeq *p3 = binaryCompareCollSeq(pParse, pLeft, pRight); return sqlite3VdbeOp3(pParse->pVdbe, opcode, p1, dest, (void*)p3, P3_COLLSEQ); } /* ** Construct a new expression node and return a pointer to it. Memory ** for this node is obtained from sqliteMalloc(). The calling function ** is responsible for making sure the node eventually gets freed. */ Expr *sqlite3Expr(int op, Expr *pLeft, Expr *pRight, const Token *pToken){ Expr *pNew; pNew = sqliteMalloc( sizeof(Expr) ); if( pNew==0 ){ /* When malloc fails, delete pLeft and pRight. Expressions passed to ** this function must always be allocated with sqlite3Expr() for this ** reason. */ sqlite3ExprDelete(pLeft); sqlite3ExprDelete(pRight); return 0; } pNew->op = op; pNew->pLeft = pLeft; pNew->pRight = pRight; pNew->iAgg = -1; if( pToken ){ assert( pToken->dyn==0 ); pNew->span = pNew->token = *pToken; }else if( pLeft && pRight ){ sqlite3ExprSpan(pNew, &pLeft->span, &pRight->span); } return pNew; } /* ** When doing a nested parse, you can include terms in an expression ** that look like this: #0 #1 #2 ... These terms refer to elements ** on the stack. "#0" means the top of the stack. ** "#1" means the next down on the stack. And so forth. ** ** This routine is called by the parser to deal with on of those terms. ** It immediately generates code to store the value in a memory location. ** The returns an expression that will code to extract the value from ** that memory location as needed. */ Expr *sqlite3RegisterExpr(Parse *pParse, Token *pToken){ Vdbe *v = pParse->pVdbe; Expr *p; int depth; if( pParse->nested==0 ){ sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", pToken); return 0; } if( v==0 ) return 0; p = sqlite3Expr(TK_REGISTER, 0, 0, pToken); if( p==0 ){ return 0; /* Malloc failed */ } depth = atoi(&pToken->z[1]); p->iTable = pParse->nMem++; sqlite3VdbeAddOp(v, OP_Dup, depth, 0); sqlite3VdbeAddOp(v, OP_MemStore, p->iTable, 1); return p; } /* ** Join two expressions using an AND operator. If either expression is ** NULL, then just return the other expression. */ Expr *sqlite3ExprAnd(Expr *pLeft, Expr *pRight){ if( pLeft==0 ){ return pRight; }else if( pRight==0 ){ return pLeft; }else{ return sqlite3Expr(TK_AND, pLeft, pRight, 0); } } /* ** Set the Expr.span field of the given expression to span all ** text between the two given tokens. */ void sqlite3ExprSpan(Expr *pExpr, Token *pLeft, Token *pRight){ assert( pRight!=0 ); assert( pLeft!=0 ); if( !sqlite3_malloc_failed && pRight->z && pLeft->z ){ assert( pLeft->dyn==0 || pLeft->z[pLeft->n]==0 ); if( pLeft->dyn==0 && pRight->dyn==0 ){ pExpr->span.z = pLeft->z; pExpr->span.n = pRight->n + (pRight->z - pLeft->z); }else{ pExpr->span.z = 0; } } } /* ** Construct a new expression node for a function with multiple ** arguments. */ Expr *sqlite3ExprFunction(ExprList *pList, Token *pToken){ Expr *pNew; pNew = sqliteMalloc( sizeof(Expr) ); if( pNew==0 ){ sqlite3ExprListDelete(pList); /* Avoid leaking memory when malloc fails */ return 0; } pNew->op = TK_FUNCTION; pNew->pList = pList; if( pToken ){ assert( pToken->dyn==0 ); pNew->token = *pToken; }else{ pNew->token.z = 0; } pNew->span = pNew->token; return pNew; } /* ** Assign a variable number to an expression that encodes a wildcard ** in the original SQL statement. ** ** Wildcards consisting of a single "?" are assigned the next sequential ** variable number. ** ** Wildcards of the form "?nnn" are assigned the number "nnn". We make ** sure "nnn" is not too be to avoid a denial of service attack when ** the SQL statement comes from an external source. ** ** Wildcards of the form ":aaa" or "$aaa" are assigned the same number ** as the previous instance of the same wildcard. Or if this is the first ** instance of the wildcard, the next sequenial variable number is ** assigned. */ void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr){ Token *pToken; if( pExpr==0 ) return; pToken = &pExpr->token; assert( pToken->n>=1 ); assert( pToken->z!=0 ); assert( pToken->z[0]!=0 ); if( pToken->n==1 ){ /* Wildcard of the form "?". Assign the next variable number */ pExpr->iTable = ++pParse->nVar; }else if( pToken->z[0]=='?' ){ /* Wildcard of the form "?nnn". Convert "nnn" to an integer and ** use it as the variable number */ int i; pExpr->iTable = i = atoi(&pToken->z[1]); if( i<1 || i>SQLITE_MAX_VARIABLE_NUMBER ){ sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d", SQLITE_MAX_VARIABLE_NUMBER); } if( i>pParse->nVar ){ pParse->nVar = i; } }else{ /* Wildcards of the form ":aaa" or "$aaa". Reuse the same variable ** number as the prior appearance of the same name, or if the name ** has never appeared before, reuse the same variable number */ int i, n; n = pToken->n; for(i=0; i<pParse->nVarExpr; i++){ Expr *pE; if( (pE = pParse->apVarExpr[i])!=0 && pE->token.n==n && memcmp(pE->token.z, pToken->z, n)==0 ){ pExpr->iTable = pE->iTable; break; } } if( i>=pParse->nVarExpr ){ pExpr->iTable = ++pParse->nVar; if( pParse->nVarExpr>=pParse->nVarExprAlloc-1 ){ pParse->nVarExprAlloc += pParse->nVarExprAlloc + 10; sqlite3ReallocOrFree((void**)&pParse->apVarExpr, pParse->nVarExprAlloc*sizeof(pParse->apVarExpr[0]) ); } if( !sqlite3_malloc_failed ){ assert( pParse->apVarExpr!=0 ); pParse->apVarExpr[pParse->nVarExpr++] = pExpr; } } } } /* ** Recursively delete an expression tree. */ void sqlite3ExprDelete(Expr *p){ if( p==0 ) return; if( p->span.dyn ) sqliteFree((char*)p->span.z); if( p->token.dyn ) sqliteFree((char*)p->token.z); sqlite3ExprDelete(p->pLeft); sqlite3ExprDelete(p->pRight); sqlite3ExprListDelete(p->pList); sqlite3SelectDelete(p->pSelect); sqliteFree(p); } /* ** The Expr.token field might be a string literal that is quoted. ** If so, remove the quotation marks. */ void sqlite3DequoteExpr(Expr *p){ if( ExprHasAnyProperty(p, EP_Dequoted) ){ return; } ExprSetProperty(p, EP_Dequoted); if( p->token.dyn==0 ){ sqlite3TokenCopy(&p->token, &p->token); } sqlite3Dequote((char*)p->token.z); } /* ** The following group of routines make deep copies of expressions, ** expression lists, ID lists, and select statements. The copies can ** be deleted (by being passed to their respective ...Delete() routines) ** without effecting the originals. ** ** The expression list, ID, and source lists return by sqlite3ExprListDup(), ** sqlite3IdListDup(), and sqlite3SrcListDup() can not be further expanded ** by subsequent calls to sqlite*ListAppend() routines. ** ** Any tables that the SrcList might point to are not duplicated. */ Expr *sqlite3ExprDup(Expr *p){ Expr *pNew; if( p==0 ) return 0; pNew = sqliteMallocRaw( sizeof(*p) ); if( pNew==0 ) return 0; memcpy(pNew, p, sizeof(*pNew)); if( p->token.z!=0 ){ pNew->token.z = sqliteStrNDup(p->token.z, p->token.n); pNew->token.dyn = 1; }else{ assert( pNew->token.z==0 ); } pNew->span.z = 0; pNew->pLeft = sqlite3ExprDup(p->pLeft); pNew->pRight = sqlite3ExprDup(p->pRight); pNew->pList = sqlite3ExprListDup(p->pList); pNew->pSelect = sqlite3SelectDup(p->pSelect); pNew->pTab = p->pTab; return pNew; } void sqlite3TokenCopy(Token *pTo, Token *pFrom){ if( pTo->dyn ) sqliteFree((char*)pTo->z); if( pFrom->z ){ pTo->n = pFrom->n; pTo->z = sqliteStrNDup(pFrom->z, pFrom->n); pTo->dyn = 1; }else{ pTo->z = 0; } } ExprList *sqlite3ExprListDup(ExprList *p){ ExprList *pNew; struct ExprList_item *pItem, *pOldItem; int i; if( p==0 ) return 0; pNew = sqliteMalloc( sizeof(*pNew) ); if( pNew==0 ) return 0; pNew->nExpr = pNew->nAlloc = p->nExpr; pNew->a = pItem = sqliteMalloc( p->nExpr*sizeof(p->a[0]) ); if( pItem==0 ){ sqliteFree(pNew); return 0; } pOldItem = p->a; for(i=0; i<p->nExpr; i++, pItem++, pOldItem++){ Expr *pNewExpr, *pOldExpr; pItem->pExpr = pNewExpr = sqlite3ExprDup(pOldExpr = pOldItem->pExpr); if( pOldExpr->span.z!=0 && pNewExpr ){ /* Always make a copy of the span for top-level expressions in the ** expression list. The logic in SELECT processing that determines ** the names of columns in the result set needs this information */ sqlite3TokenCopy(&pNewExpr->span, &pOldExpr->span); } assert( pNewExpr==0 || pNewExpr->span.z!=0 || pOldExpr->span.z==0 || sqlite3_malloc_failed ); pItem->zName = sqliteStrDup(pOldItem->zName); pItem->sortOrder = pOldItem->sortOrder; pItem->isAgg = pOldItem->isAgg; pItem->done = 0; } return pNew; } /* ** If cursors, triggers, views and subqueries are all omitted from ** the build, then none of the following routines, except for ** sqlite3SelectDup(), can be called. sqlite3SelectDup() is sometimes ** called with a NULL argument. */ #if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) \ || !defined(SQLITE_OMIT_SUBQUERY) SrcList *sqlite3SrcListDup(SrcList *p){ SrcList *pNew; int i; int nByte; if( p==0 ) return 0; nByte = sizeof(*p) + (p->nSrc>0 ? sizeof(p->a[0]) * (p->nSrc-1) : 0); pNew = sqliteMallocRaw( nByte ); if( pNew==0 ) return 0; pNew->nSrc = pNew->nAlloc = p->nSrc; for(i=0; i<p->nSrc; i++){ struct SrcList_item *pNewItem = &pNew->a[i]; struct SrcList_item *pOldItem = &p->a[i]; Table *pTab; pNewItem->zDatabase = sqliteStrDup(pOldItem->zDatabase); pNewItem->zName = sqliteStrDup(pOldItem->zName); pNewItem->zAlias = sqliteStrDup(pOldItem->zAlias); pNewItem->jointype = pOldItem->jointype; pNewItem->iCursor = pOldItem->iCursor; pTab = pNewItem->pTab = pOldItem->pTab; if( pTab ){ pTab->nRef++; } pNewItem->pSelect = sqlite3SelectDup(pOldItem->pSelect); pNewItem->pOn = sqlite3ExprDup(pOldItem->pOn); pNewItem->pUsing = sqlite3IdListDup(pOldItem->pUsing); pNewItem->colUsed = pOldItem->colUsed; } return pNew; } IdList *sqlite3IdListDup(IdList *p){ IdList *pNew; int i; if( p==0 ) return 0; pNew = sqliteMallocRaw( sizeof(*pNew) ); if( pNew==0 ) return 0; pNew->nId = pNew->nAlloc = p->nId; pNew->a = sqliteMallocRaw( p->nId*sizeof(p->a[0]) ); if( pNew->a==0 ){ sqliteFree(pNew); return 0; } for(i=0; i<p->nId; i++){ struct IdList_item *pNewItem = &pNew->a[i]; struct IdList_item *pOldItem = &p->a[i]; pNewItem->zName = sqliteStrDup(pOldItem->zName); pNewItem->idx = pOldItem->idx; } return pNew; } Select *sqlite3SelectDup(Select *p){ Select *pNew; if( p==0 ) return 0; pNew = sqliteMallocRaw( sizeof(*p) ); if( pNew==0 ) return 0; pNew->isDistinct = p->isDistinct; pNew->pEList = sqlite3ExprListDup(p->pEList); pNew->pSrc = sqlite3SrcListDup(p->pSrc); pNew->pWhere = sqlite3ExprDup(p->pWhere); pNew->pGroupBy = sqlite3ExprListDup(p->pGroupBy); pNew->pHaving = sqlite3ExprDup(p->pHaving); pNew->pOrderBy = sqlite3ExprListDup(p->pOrderBy); pNew->op = p->op; pNew->pPrior = sqlite3SelectDup(p->pPrior); pNew->pLimit = sqlite3ExprDup(p->pLimit); pNew->pOffset = sqlite3ExprDup(p->pOffset); pNew->iLimit = -1; pNew->iOffset = -1; pNew->isResolved = p->isResolved; pNew->isAgg = p->isAgg; pNew->pRightmost = 0; pNew->addrOpenVirt[0] = -1; pNew->addrOpenVirt[1] = -1; pNew->addrOpenVirt[2] = -1; return pNew; } #else Select *sqlite3SelectDup(Select *p){ assert( p==0 ); return 0; } #endif /* ** Add a new element to the end of an expression list. If pList is ** initially NULL, then create a new expression list. */ ExprList *sqlite3ExprListAppend(ExprList *pList, Expr *pExpr, Token *pName){ if( pList==0 ){ pList = sqliteMalloc( sizeof(ExprList) ); if( pList==0 ){ goto no_mem; } assert( pList->nAlloc==0 ); } if( pList->nAlloc<=pList->nExpr ){ struct ExprList_item *a; int n = pList->nAlloc*2 + 4; a = sqliteRealloc(pList->a, n*sizeof(pList->a[0])); if( a==0 ){ goto no_mem; } pList->a = a; pList->nAlloc = n; } assert( pList->a!=0 ); if( pExpr || pName ){ struct ExprList_item *pItem = &pList->a[pList->nExpr++]; memset(pItem, 0, sizeof(*pItem)); pItem->zName = sqlite3NameFromToken(pName); pItem->pExpr = pExpr; } return pList; no_mem: /* Avoid leaking memory if malloc has failed. */ sqlite3ExprDelete(pExpr); sqlite3ExprListDelete(pList); return 0; } /* ** Delete an entire expression list. */ void sqlite3ExprListDelete(ExprList *pList){ int i; struct ExprList_item *pItem; if( pList==0 ) return; assert( pList->a!=0 || (pList->nExpr==0 && pList->nAlloc==0) ); assert( pList->nExpr<=pList->nAlloc ); for(pItem=pList->a, i=0; i<pList->nExpr; i++, pItem++){ sqlite3ExprDelete(pItem->pExpr); sqliteFree(pItem->zName); } sqliteFree(pList->a); sqliteFree(pList); } /* ** Walk an expression tree. Call xFunc for each node visited. ** ** The return value from xFunc determines whether the tree walk continues. ** 0 means continue walking the tree. 1 means do not walk children ** of the current node but continue with siblings. 2 means abandon ** the tree walk completely. ** ** The return value from this routine is 1 to abandon the tree walk ** and 0 to continue. ** ** NOTICE: This routine does *not* descend into subqueries. */ static int walkExprList(ExprList *, int (*)(void *, Expr*), void *); static int walkExprTree(Expr *pExpr, int (*xFunc)(void*,Expr*), void *pArg){ int rc; if( pExpr==0 ) return 0; rc = (*xFunc)(pArg, pExpr); if( rc==0 ){ if( walkExprTree(pExpr->pLeft, xFunc, pArg) ) return 1; if( walkExprTree(pExpr->pRight, xFunc, pArg) ) return 1; if( walkExprList(pExpr->pList, xFunc, pArg) ) return 1; } return rc>1; } /* ** Call walkExprTree() for every expression in list p. */ static int walkExprList(ExprList *p, int (*xFunc)(void *, Expr*), void *pArg){ int i; struct ExprList_item *pItem; if( !p ) return 0; for(i=p->nExpr, pItem=p->a; i>0; i--, pItem++){ if( walkExprTree(pItem->pExpr, xFunc, pArg) ) return 1; } return 0; } /* ** Call walkExprTree() for every expression in Select p, not including ** expressions that are part of sub-selects in any FROM clause or the LIMIT ** or OFFSET expressions.. */ static int walkSelectExpr(Select *p, int (*xFunc)(void *, Expr*), void *pArg){ walkExprList(p->pEList, xFunc, pArg); walkExprTree(p->pWhere, xFunc, pArg); walkExprList(p->pGroupBy, xFunc, pArg); walkExprTree(p->pHaving, xFunc, pArg); walkExprList(p->pOrderBy, xFunc, pArg); return 0; } /* ** This routine is designed as an xFunc for walkExprTree(). ** ** pArg is really a pointer to an integer. If we can tell by looking ** at pExpr that the expression that contains pExpr is not a constant ** expression, then set *pArg to 0 and return 2 to abandon the tree walk. ** If pExpr does does not disqualify the expression from being a constant ** then do nothing. ** ** After walking the whole tree, if no nodes are found that disqualify ** the expression as constant, then we assume the whole expression ** is constant. See sqlite3ExprIsConstant() for additional information. */ static int exprNodeIsConstant(void *pArg, Expr *pExpr){ switch( pExpr->op ){ /* Consider functions to be constant if all their arguments are constant ** and *pArg==2 */ case TK_FUNCTION: if( *((int*)pArg)==2 ) return 0; /* Fall through */ case TK_ID: case TK_COLUMN: case TK_DOT: case TK_AGG_FUNCTION: case TK_AGG_COLUMN: #ifndef SQLITE_OMIT_SUBQUERY case TK_SELECT: case TK_EXISTS: #endif *((int*)pArg) = 0; return 2; case TK_IN: if( pExpr->pSelect ){ *((int*)pArg) = 0; return 2; } default: return 0; } } /* ** Walk an expression tree. Return 1 if the expression is constant ** and 0 if it involves variables or function calls. ** ** For the purposes of this function, a double-quoted string (ex: "abc") ** is considered a variable but a single-quoted string (ex: 'abc') is ** a constant. */ int sqlite3ExprIsConstant(Expr *p){ int isConst = 1; walkExprTree(p, exprNodeIsConstant, &isConst); return isConst; } /* ** Walk an expression tree. Return 1 if the expression is constant ** or a function call with constant arguments. Return and 0 if there ** are any variables. ** ** For the purposes of this function, a double-quoted string (ex: "abc") ** is considered a variable but a single-quoted string (ex: 'abc') is ** a constant. */ int sqlite3ExprIsConstantOrFunction(Expr *p){ int isConst = 2; walkExprTree(p, exprNodeIsConstant, &isConst); return isConst!=0; } /* ** If the expression p codes a constant integer that is small enough ** to fit in a 32-bit integer, return 1 and put the value of the integer ** in *pValue. If the expression is not an integer or if it is too big ** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged. */ int sqlite3ExprIsInteger(Expr *p, int *pValue){ switch( p->op ){ case TK_INTEGER: { if( sqlite3GetInt32(p->token.z, pValue) ){ return 1; } break; } case TK_UPLUS: { return sqlite3ExprIsInteger(p->pLeft, pValue); } case TK_UMINUS: { int v; if( sqlite3ExprIsInteger(p->pLeft, &v) ){ *pValue = -v; return 1; } break; } default: break; } return 0; } /* ** Return TRUE if the given string is a row-id column name. */ int sqlite3IsRowid(const char *z){ if( sqlite3StrICmp(z, "_ROWID_")==0 ) return 1; if( sqlite3StrICmp(z, "ROWID")==0 ) return 1; if( sqlite3StrICmp(z, "OID")==0 ) return 1; return 0; } /* ** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up ** that name in the set of source tables in pSrcList and make the pExpr ** expression node refer back to that source column. The following changes ** are made to pExpr: ** ** pExpr->iDb Set the index in db->aDb[] of the database holding ** the table. ** pExpr->iTable Set to the cursor number for the table obtained ** from pSrcList. ** pExpr->iColumn Set to the column number within the table. ** pExpr->op Set to TK_COLUMN. ** pExpr->pLeft Any expression this points to is deleted ** pExpr->pRight Any expression this points to is deleted. ** ** The pDbToken is the name of the database (the "X"). This value may be ** NULL meaning that name is of the form Y.Z or Z. Any available database ** can be used. The pTableToken is the name of the table (the "Y"). This ** value can be NULL if pDbToken is also NULL. If pTableToken is NULL it ** means that the form of the name is Z and that columns from any table ** can be used. ** ** If the name cannot be resolved unambiguously, leave an error message ** in pParse and return non-zero. Return zero on success. */ static int lookupName( Parse *pParse, /* The parsing context */ Token *pDbToken, /* Name of the database containing table, or NULL */ Token *pTableToken, /* Name of table containing column, or NULL */ Token *pColumnToken, /* Name of the column. */ NameContext *pNC, /* The name context used to resolve the name */ Expr *pExpr /* Make this EXPR node point to the selected column */ ){ char *zDb = 0; /* Name of the database. The "X" in X.Y.Z */ char *zTab = 0; /* Name of the table. The "Y" in X.Y.Z or Y.Z */ char *zCol = 0; /* Name of the column. The "Z" */ int i, j; /* Loop counters */ int cnt = 0; /* Number of matching column names */ int cntTab = 0; /* Number of matching table names */ sqlite3 *db = pParse->db; /* The database */ struct SrcList_item *pItem; /* Use for looping over pSrcList items */ struct SrcList_item *pMatch = 0; /* The matching pSrcList item */ NameContext *pTopNC = pNC; /* First namecontext in the list */ assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */ zDb = sqlite3NameFromToken(pDbToken); zTab = sqlite3NameFromToken(pTableToken); zCol = sqlite3NameFromToken(pColumnToken); if( sqlite3_malloc_failed ){ goto lookupname_end; } pExpr->iTable = -1; while( pNC && cnt==0 ){ SrcList *pSrcList = pNC->pSrcList; ExprList *pEList = pNC->pEList; /* assert( zTab==0 || pEList==0 ); */ if( pSrcList ){ for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){ Table *pTab = pItem->pTab; Column *pCol; if( pTab==0 ) continue; assert( pTab->nCol>0 ); if( zTab ){ if( pItem->zAlias ){ char *zTabName = pItem->zAlias; if( sqlite3StrICmp(zTabName, zTab)!=0 ) continue; }else{ char *zTabName = pTab->zName; if( zTabName==0 || sqlite3StrICmp(zTabName, zTab)!=0 ) continue; if( zDb!=0 && sqlite3StrICmp(db->aDb[pTab->iDb].zName, zDb)!=0 ){ continue; } } } if( 0==(cntTab++) ){ pExpr->iTable = pItem->iCursor; pExpr->iDb = pTab->iDb; pMatch = pItem; } for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){ if( sqlite3StrICmp(pCol->zName, zCol)==0 ){ IdList *pUsing; cnt++; pExpr->iTable = pItem->iCursor; pMatch = pItem; pExpr->iDb = pTab->iDb; /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */ pExpr->iColumn = j==pTab->iPKey ? -1 : j; pExpr->affinity = pTab->aCol[j].affinity; pExpr->pColl = pTab->aCol[j].pColl; if( pItem->jointype & JT_NATURAL ){ /* If this match occurred in the left table of a natural join, ** then skip the right table to avoid a duplicate match */ pItem++; i++; } if( (pUsing = pItem->pUsing)!=0 ){ /* If this match occurs on a column that is in the USING clause ** of a join, skip the search of the right table of the join ** to avoid a duplicate match there. */ int k; for(k=0; k<pUsing->nId; k++){ if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ){ pItem++; i++; break; } } } break; } } } } #ifndef SQLITE_OMIT_TRIGGER /* If we have not already resolved the name, then maybe ** it is a new.* or old.* trigger argument reference */ if( zDb==0 && zTab!=0 && cnt==0 && pParse->trigStack!=0 ){ TriggerStack *pTriggerStack = pParse->trigStack; Table *pTab = 0; if( pTriggerStack->newIdx != -1 && sqlite3StrICmp("new", zTab) == 0 ){ pExpr->iTable = pTriggerStack->newIdx; assert( pTriggerStack->pTab ); pTab = pTriggerStack->pTab; }else if( pTriggerStack->oldIdx != -1 && sqlite3StrICmp("old", zTab)==0 ){ pExpr->iTable = pTriggerStack->oldIdx; assert( pTriggerStack->pTab ); pTab = pTriggerStack->pTab; } if( pTab ){ int j; Column *pCol = pTab->aCol; pExpr->iDb = pTab->iDb; cntTab++; for(j=0; j < pTab->nCol; j++, pCol++) { if( sqlite3StrICmp(pCol->zName, zCol)==0 ){ cnt++; pExpr->iColumn = j==pTab->iPKey ? -1 : j; pExpr->affinity = pTab->aCol[j].affinity; pExpr->pColl = pTab->aCol[j].pColl; pExpr->pTab = pTab; break; } } } } #endif /* !defined(SQLITE_OMIT_TRIGGER) */ /* ** Perhaps the name is a reference to the ROWID */ if( cnt==0 && cntTab==1 && sqlite3IsRowid(zCol) ){ cnt = 1; pExpr->iColumn = -1; pExpr->affinity = SQLITE_AFF_INTEGER; } /* ** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z ** might refer to an result-set alias. This happens, for example, when ** we are resolving names in the WHERE clause of the following command: ** ** SELECT a+b AS x FROM table WHERE x<10; ** ** In cases like this, replace pExpr with a copy of the expression that ** forms the result set entry ("a+b" in the example) and return immediately. ** Note that the expression in the result set should have already been ** resolved by the time the WHERE clause is resolved. */ if( cnt==0 && pEList!=0 && zTab==0 ){ for(j=0; j<pEList->nExpr; j++){ char *zAs = pEList->a[j].zName; if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){ assert( pExpr->pLeft==0 && pExpr->pRight==0 ); pExpr->op = TK_AS; pExpr->iColumn = j; pExpr->pLeft = sqlite3ExprDup(pEList->a[j].pExpr); cnt = 1; assert( zTab==0 && zDb==0 ); goto lookupname_end_2; } } } /* Advance to the next name context. The loop will exit when either ** we have a match (cnt>0) or when we run out of name contexts. */ if( cnt==0 ){ pNC = pNC->pNext; } } /* ** If X and Y are NULL (in other words if only the column name Z is ** supplied) and the value of Z is enclosed in double-quotes, then ** Z is a string literal if it doesn't match any column names. In that ** case, we need to return right away and not make any changes to ** pExpr. ** ** Because no reference was made to outer contexts, the pNC->nRef ** fields are not changed in any context. */ if( cnt==0 && zTab==0 && pColumnToken->z[0]=='"' ){ sqliteFree(zCol); return 0; } /* ** cnt==0 means there was not match. cnt>1 means there were two or ** more matches. Either way, we have an error. */ if( cnt!=1 ){ char *z = 0; char *zErr; zErr = cnt==0 ? "no such column: %s" : "ambiguous column name: %s"; if( zDb ){ sqlite3SetString(&z, zDb, ".", zTab, ".", zCol, 0); }else if( zTab ){ sqlite3SetString(&z, zTab, ".", zCol, 0); }else{ z = sqliteStrDup(zCol); } sqlite3ErrorMsg(pParse, zErr, z); sqliteFree(z); pTopNC->nErr++; } /* If a column from a table in pSrcList is referenced, then record ** this fact in the pSrcList.a[].colUsed bitmask. Column 0 causes ** bit 0 to be set. Column 1 sets bit 1. And so forth. If the ** column number is greater than the number of bits in the bitmask ** then set the high-order bit of the bitmask. */ if( pExpr->iColumn>=0 && pMatch!=0 ){ int n = pExpr->iColumn; if( n>=sizeof(Bitmask)*8 ){ n = sizeof(Bitmask)*8-1; } assert( pMatch->iCursor==pExpr->iTable ); pMatch->colUsed |= 1<<n; } lookupname_end: /* Clean up and return */ sqliteFree(zDb); sqliteFree(zTab); sqlite3ExprDelete(pExpr->pLeft); pExpr->pLeft = 0; sqlite3ExprDelete(pExpr->pRight); pExpr->pRight = 0; pExpr->op = TK_COLUMN; lookupname_end_2: sqliteFree(zCol); if( cnt==1 ){ assert( pNC!=0 ); sqlite3AuthRead(pParse, pExpr, pNC->pSrcList); if( pMatch && !pMatch->pSelect ){ pExpr->pTab = pMatch->pTab; } /* Increment the nRef value on all name contexts from TopNC up to ** the point where the name matched. */ for(;;){ assert( pTopNC!=0 ); pTopNC->nRef++; if( pTopNC==pNC ) break; pTopNC = pTopNC->pNext; } return 0; } else { return 1; } } /* ** This routine is designed as an xFunc for walkExprTree(). ** ** Resolve symbolic names into TK_COLUMN operators for the current ** node in the expression tree. Return 0 to continue the search down ** the tree or 2 to abort the tree walk. ** ** This routine also does error checking and name resolution for ** function names. The operator for aggregate functions is changed ** to TK_AGG_FUNCTION. */ static int nameResolverStep(void *pArg, Expr *pExpr){ NameContext *pNC = (NameContext*)pArg; SrcList *pSrcList; Parse *pParse; if( pExpr==0 ) return 1; assert( pNC!=0 ); pSrcList = pNC->pSrcList; pParse = pNC->pParse; if( ExprHasAnyProperty(pExpr, EP_Resolved) ) return 1; ExprSetProperty(pExpr, EP_Resolved); #ifndef NDEBUG if( pSrcList ){ int i; for(i=0; i<pSrcList->nSrc; i++){ assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab); } } #endif switch( pExpr->op ){ /* Double-quoted strings (ex: "abc") are used as identifiers if ** possible. Otherwise they remain as strings. Single-quoted ** strings (ex: 'abc') are always string literals. */ case TK_STRING: { if( pExpr->token.z[0]=='\'' ) break; /* Fall thru into the TK_ID case if this is a double-quoted string */ } /* A lone identifier is the name of a column. */ case TK_ID: { lookupName(pParse, 0, 0, &pExpr->token, pNC, pExpr); return 1; } /* A table name and column name: ID.ID ** Or a database, table and column: ID.ID.ID */ case TK_DOT: { Token *pColumn; Token *pTable; Token *pDb; Expr *pRight; /* if( pSrcList==0 ) break; */ pRight = pExpr->pRight; if( pRight->op==TK_ID ){ pDb = 0; pTable = &pExpr->pLeft->token; pColumn = &pRight->token; }else{ assert( pRight->op==TK_DOT ); pDb = &pExpr->pLeft->token; pTable = &pRight->pLeft->token; pColumn = &pRight->pRight->token; } lookupName(pParse, pDb, pTable, pColumn, pNC, pExpr); return 1; } /* Resolve function names */ case TK_CONST_FUNC: case TK_FUNCTION: { ExprList *pList = pExpr->pList; /* The argument list */ int n = pList ? pList->nExpr : 0; /* Number of arguments */ int no_such_func = 0; /* True if no such function exists */ int wrong_num_args = 0; /* True if wrong number of