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5519 lines (5259 loc) · 189 KB
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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.
*/
#include "sqliteInt.h"
/* Forward declarations */
static void exprCodeBetween(Parse*,Expr*,int,void(*)(Parse*,Expr*,int,int),int);
static int exprCodeVector(Parse *pParse, Expr *p, int *piToFree);
/*
** Return the affinity character for a single column of a table.
*/
char sqlite3TableColumnAffinity(Table *pTab, int iCol){
assert( iCol<pTab->nCol );
return iCol>=0 ? pTab->aCol[iCol].affinity : SQLITE_AFF_INTEGER;
}
/*
** 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 expressions 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 = sqlite3ExprSkipCollate(pExpr);
if( pExpr->flags & EP_Generic ) return 0;
op = pExpr->op;
if( op==TK_SELECT ){
assert( pExpr->flags&EP_xIsSelect );
return sqlite3ExprAffinity(pExpr->x.pSelect->pEList->a[0].pExpr);
}
if( op==TK_REGISTER ) op = pExpr->op2;
#ifndef SQLITE_OMIT_CAST
if( op==TK_CAST ){
assert( !ExprHasProperty(pExpr, EP_IntValue) );
return sqlite3AffinityType(pExpr->u.zToken, 0);
}
#endif
if( (op==TK_AGG_COLUMN || op==TK_COLUMN) && pExpr->pTab ){
return sqlite3TableColumnAffinity(pExpr->pTab, pExpr->iColumn);
}
if( op==TK_SELECT_COLUMN ){
assert( pExpr->pLeft->flags&EP_xIsSelect );
return sqlite3ExprAffinity(
pExpr->pLeft->x.pSelect->pEList->a[pExpr->iColumn].pExpr
);
}
return pExpr->affinity;
}
/*
** Set the collating sequence for expression pExpr to be the collating
** sequence named by pToken. Return a pointer to a new Expr node that
** implements the COLLATE operator.
**
** If a memory allocation error occurs, that fact is recorded in pParse->db
** and the pExpr parameter is returned unchanged.
*/
Expr *sqlite3ExprAddCollateToken(
Parse *pParse, /* Parsing context */
Expr *pExpr, /* Add the "COLLATE" clause to this expression */
const Token *pCollName, /* Name of collating sequence */
int dequote /* True to dequote pCollName */
){
if( pCollName->n>0 ){
Expr *pNew = sqlite3ExprAlloc(pParse->db, TK_COLLATE, pCollName, dequote);
if( pNew ){
pNew->pLeft = pExpr;
pNew->flags |= EP_Collate|EP_Skip;
pExpr = pNew;
}
}
return pExpr;
}
Expr *sqlite3ExprAddCollateString(Parse *pParse, Expr *pExpr, const char *zC){
Token s;
assert( zC!=0 );
sqlite3TokenInit(&s, (char*)zC);
return sqlite3ExprAddCollateToken(pParse, pExpr, &s, 0);
}
/*
** Skip over any TK_COLLATE operators and any unlikely()
** or likelihood() function at the root of an expression.
*/
Expr *sqlite3ExprSkipCollate(Expr *pExpr){
while( pExpr && ExprHasProperty(pExpr, EP_Skip) ){
if( ExprHasProperty(pExpr, EP_Unlikely) ){
assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
assert( pExpr->x.pList->nExpr>0 );
assert( pExpr->op==TK_FUNCTION );
pExpr = pExpr->x.pList->a[0].pExpr;
}else{
assert( pExpr->op==TK_COLLATE );
pExpr = pExpr->pLeft;
}
}
return pExpr;
}
/*
** Return the collation sequence for the expression pExpr. If
** there is no defined collating sequence, return NULL.
**
** See also: sqlite3ExprNNCollSeq()
**
** The sqlite3ExprNNCollSeq() works the same exact that it returns the
** default collation if pExpr has no defined collation.
**
** The collating sequence might be determined by a COLLATE operator
** or by the presence of a column with a defined collating sequence.
** COLLATE operators take first precedence. Left operands take
** precedence over right operands.
*/
CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr){
sqlite3 *db = pParse->db;
CollSeq *pColl = 0;
Expr *p = pExpr;
while( p ){
int op = p->op;
if( p->flags & EP_Generic ) break;
if( op==TK_CAST || op==TK_UPLUS ){
p = p->pLeft;
continue;
}
if( op==TK_COLLATE || (op==TK_REGISTER && p->op2==TK_COLLATE) ){
pColl = sqlite3GetCollSeq(pParse, ENC(db), 0, p->u.zToken);
break;
}
if( (op==TK_AGG_COLUMN || op==TK_COLUMN
|| op==TK_REGISTER || op==TK_TRIGGER)
&& p->pTab!=0
){
/* op==TK_REGISTER && p->pTab!=0 happens when pExpr was originally
** a TK_COLUMN but was previously evaluated and cached in a register */
int j = p->iColumn;
if( j>=0 ){
const char *zColl = p->pTab->aCol[j].zColl;
pColl = sqlite3FindCollSeq(db, ENC(db), zColl, 0);
}
break;
}
if( p->flags & EP_Collate ){
if( p->pLeft && (p->pLeft->flags & EP_Collate)!=0 ){
p = p->pLeft;
}else{
Expr *pNext = p->pRight;
/* The Expr.x union is never used at the same time as Expr.pRight */
assert( p->x.pList==0 || p->pRight==0 );
/* p->flags holds EP_Collate and p->pLeft->flags does not. And
** p->x.pSelect cannot. So if p->x.pLeft exists, it must hold at
** least one EP_Collate. Thus the following two ALWAYS. */
if( p->x.pList!=0 && ALWAYS(!ExprHasProperty(p, EP_xIsSelect)) ){
int i;
for(i=0; ALWAYS(i<p->x.pList->nExpr); i++){
if( ExprHasProperty(p->x.pList->a[i].pExpr, EP_Collate) ){
pNext = p->x.pList->a[i].pExpr;
break;
}
}
}
p = pNext;
}
}else{
break;
}
}
if( sqlite3CheckCollSeq(pParse, pColl) ){
pColl = 0;
}
return pColl;
}
/*
** Return the collation sequence for the expression pExpr. If
** there is no defined collating sequence, return a pointer to the
** defautl collation sequence.
**
** See also: sqlite3ExprCollSeq()
**
** The sqlite3ExprCollSeq() routine works the same except that it
** returns NULL if there is no defined collation.
*/
CollSeq *sqlite3ExprNNCollSeq(Parse *pParse, Expr *pExpr){
CollSeq *p = sqlite3ExprCollSeq(pParse, pExpr);
if( p==0 ) p = pParse->db->pDfltColl;
assert( p!=0 );
return p;
}
/*
** Return TRUE if the two expressions have equivalent collating sequences.
*/
int sqlite3ExprCollSeqMatch(Parse *pParse, Expr *pE1, Expr *pE2){
CollSeq *pColl1 = sqlite3ExprNNCollSeq(pParse, pE1);
CollSeq *pColl2 = sqlite3ExprNNCollSeq(pParse, pE2);
return sqlite3StrICmp(pColl1->zName, pColl2->zName)==0;
}
/*
** 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
** affinity, use that. Otherwise use no affinity.
*/
if( sqlite3IsNumericAffinity(aff1) || sqlite3IsNumericAffinity(aff2) ){
return SQLITE_AFF_NUMERIC;
}else{
return SQLITE_AFF_BLOB;
}
}else if( !aff1 && !aff2 ){
/* Neither side of the comparison is a column. Compare the
** results directly.
*/
return SQLITE_AFF_BLOB;
}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 || pExpr->op==TK_IS || pExpr->op==TK_ISNOT );
assert( pExpr->pLeft );
aff = sqlite3ExprAffinity(pExpr->pLeft);
if( pExpr->pRight ){
aff = sqlite3CompareAffinity(pExpr->pRight, aff);
}else if( ExprHasProperty(pExpr, EP_xIsSelect) ){
aff = sqlite3CompareAffinity(pExpr->x.pSelect->pEList->a[0].pExpr, aff);
}else if( aff==0 ){
aff = SQLITE_AFF_BLOB;
}
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);
switch( aff ){
case SQLITE_AFF_BLOB:
return 1;
case SQLITE_AFF_TEXT:
return idx_affinity==SQLITE_AFF_TEXT;
default:
return sqlite3IsNumericAffinity(idx_affinity);
}
}
/*
** Return the P5 value that should be used for a binary comparison
** opcode (OP_Eq, OP_Ge etc.) used to compare pExpr1 and pExpr2.
*/
static u8 binaryCompareP5(Expr *pExpr1, Expr *pExpr2, int jumpIfNull){
u8 aff = (char)sqlite3ExprAffinity(pExpr2);
aff = (u8)sqlite3CompareAffinity(pExpr1, aff) | (u8)jumpIfNull;
return aff;
}
/*
** 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.
**
** Argument pRight (but not pLeft) may be a null pointer. In this case,
** it is not considered.
*/
CollSeq *sqlite3BinaryCompareCollSeq(
Parse *pParse,
Expr *pLeft,
Expr *pRight
){
CollSeq *pColl;
assert( pLeft );
if( pLeft->flags & EP_Collate ){
pColl = sqlite3ExprCollSeq(pParse, pLeft);
}else if( pRight && (pRight->flags & EP_Collate)!=0 ){
pColl = sqlite3ExprCollSeq(pParse, pRight);
}else{
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 in1, int in2, /* Register holding operands */
int dest, /* Jump here if true. */
int jumpIfNull /* If true, jump if either operand is NULL */
){
int p5;
int addr;
CollSeq *p4;
p4 = sqlite3BinaryCompareCollSeq(pParse, pLeft, pRight);
p5 = binaryCompareP5(pLeft, pRight, jumpIfNull);
addr = sqlite3VdbeAddOp4(pParse->pVdbe, opcode, in2, dest, in1,
(void*)p4, P4_COLLSEQ);
sqlite3VdbeChangeP5(pParse->pVdbe, (u8)p5);
return addr;
}
/*
** Return true if expression pExpr is a vector, or false otherwise.
**
** A vector is defined as any expression that results in two or more
** columns of result. Every TK_VECTOR node is an vector because the
** parser will not generate a TK_VECTOR with fewer than two entries.
** But a TK_SELECT might be either a vector or a scalar. It is only
** considered a vector if it has two or more result columns.
*/
int sqlite3ExprIsVector(Expr *pExpr){
return sqlite3ExprVectorSize(pExpr)>1;
}
/*
** If the expression passed as the only argument is of type TK_VECTOR
** return the number of expressions in the vector. Or, if the expression
** is a sub-select, return the number of columns in the sub-select. For
** any other type of expression, return 1.
*/
int sqlite3ExprVectorSize(Expr *pExpr){
u8 op = pExpr->op;
if( op==TK_REGISTER ) op = pExpr->op2;
if( op==TK_VECTOR ){
return pExpr->x.pList->nExpr;
}else if( op==TK_SELECT ){
return pExpr->x.pSelect->pEList->nExpr;
}else{
return 1;
}
}
/*
** Return a pointer to a subexpression of pVector that is the i-th
** column of the vector (numbered starting with 0). The caller must
** ensure that i is within range.
**
** If pVector is really a scalar (and "scalar" here includes subqueries
** that return a single column!) then return pVector unmodified.
**
** pVector retains ownership of the returned subexpression.
**
** If the vector is a (SELECT ...) then the expression returned is
** just the expression for the i-th term of the result set, and may
** not be ready for evaluation because the table cursor has not yet
** been positioned.
*/
Expr *sqlite3VectorFieldSubexpr(Expr *pVector, int i){
assert( i<sqlite3ExprVectorSize(pVector) );
if( sqlite3ExprIsVector(pVector) ){
assert( pVector->op2==0 || pVector->op==TK_REGISTER );
if( pVector->op==TK_SELECT || pVector->op2==TK_SELECT ){
return pVector->x.pSelect->pEList->a[i].pExpr;
}else{
return pVector->x.pList->a[i].pExpr;
}
}
return pVector;
}
/*
** Compute and return a new Expr object which when passed to
** sqlite3ExprCode() will generate all necessary code to compute
** the iField-th column of the vector expression pVector.
**
** It is ok for pVector to be a scalar (as long as iField==0).
** In that case, this routine works like sqlite3ExprDup().
**
** The caller owns the returned Expr object and is responsible for
** ensuring that the returned value eventually gets freed.
**
** The caller retains ownership of pVector. If pVector is a TK_SELECT,
** then the returned object will reference pVector and so pVector must remain
** valid for the life of the returned object. If pVector is a TK_VECTOR
** or a scalar expression, then it can be deleted as soon as this routine
** returns.
**
** A trick to cause a TK_SELECT pVector to be deleted together with
** the returned Expr object is to attach the pVector to the pRight field
** of the returned TK_SELECT_COLUMN Expr object.
*/
Expr *sqlite3ExprForVectorField(
Parse *pParse, /* Parsing context */
Expr *pVector, /* The vector. List of expressions or a sub-SELECT */
int iField /* Which column of the vector to return */
){
Expr *pRet;
if( pVector->op==TK_SELECT ){
assert( pVector->flags & EP_xIsSelect );
/* The TK_SELECT_COLUMN Expr node:
**
** pLeft: pVector containing TK_SELECT. Not deleted.
** pRight: not used. But recursively deleted.
** iColumn: Index of a column in pVector
** iTable: 0 or the number of columns on the LHS of an assignment
** pLeft->iTable: First in an array of register holding result, or 0
** if the result is not yet computed.
**
** sqlite3ExprDelete() specifically skips the recursive delete of
** pLeft on TK_SELECT_COLUMN nodes. But pRight is followed, so pVector
** can be attached to pRight to cause this node to take ownership of
** pVector. Typically there will be multiple TK_SELECT_COLUMN nodes
** with the same pLeft pointer to the pVector, but only one of them
** will own the pVector.
*/
pRet = sqlite3PExpr(pParse, TK_SELECT_COLUMN, 0, 0);
if( pRet ){
pRet->iColumn = iField;
pRet->pLeft = pVector;
}
assert( pRet==0 || pRet->iTable==0 );
}else{
if( pVector->op==TK_VECTOR ) pVector = pVector->x.pList->a[iField].pExpr;
pRet = sqlite3ExprDup(pParse->db, pVector, 0);
}
return pRet;
}
/*
** If expression pExpr is of type TK_SELECT, generate code to evaluate
** it. Return the register in which the result is stored (or, if the
** sub-select returns more than one column, the first in an array
** of registers in which the result is stored).
**
** If pExpr is not a TK_SELECT expression, return 0.
*/
static int exprCodeSubselect(Parse *pParse, Expr *pExpr){
int reg = 0;
#ifndef SQLITE_OMIT_SUBQUERY
if( pExpr->op==TK_SELECT ){
reg = sqlite3CodeSubselect(pParse, pExpr, 0, 0);
}
#endif
return reg;
}
/*
** Argument pVector points to a vector expression - either a TK_VECTOR
** or TK_SELECT that returns more than one column. This function returns
** the register number of a register that contains the value of
** element iField of the vector.
**
** If pVector is a TK_SELECT expression, then code for it must have
** already been generated using the exprCodeSubselect() routine. In this
** case parameter regSelect should be the first in an array of registers
** containing the results of the sub-select.
**
** If pVector is of type TK_VECTOR, then code for the requested field
** is generated. In this case (*pRegFree) may be set to the number of
** a temporary register to be freed by the caller before returning.
**
** Before returning, output parameter (*ppExpr) is set to point to the
** Expr object corresponding to element iElem of the vector.
*/
static int exprVectorRegister(
Parse *pParse, /* Parse context */
Expr *pVector, /* Vector to extract element from */
int iField, /* Field to extract from pVector */
int regSelect, /* First in array of registers */
Expr **ppExpr, /* OUT: Expression element */
int *pRegFree /* OUT: Temp register to free */
){
u8 op = pVector->op;
assert( op==TK_VECTOR || op==TK_REGISTER || op==TK_SELECT );
if( op==TK_REGISTER ){
*ppExpr = sqlite3VectorFieldSubexpr(pVector, iField);
return pVector->iTable+iField;
}
if( op==TK_SELECT ){
*ppExpr = pVector->x.pSelect->pEList->a[iField].pExpr;
return regSelect+iField;
}
*ppExpr = pVector->x.pList->a[iField].pExpr;
return sqlite3ExprCodeTemp(pParse, *ppExpr, pRegFree);
}
/*
** Expression pExpr is a comparison between two vector values. Compute
** the result of the comparison (1, 0, or NULL) and write that
** result into register dest.
**
** The caller must satisfy the following preconditions:
**
** if pExpr->op==TK_IS: op==TK_EQ and p5==SQLITE_NULLEQ
** if pExpr->op==TK_ISNOT: op==TK_NE and p5==SQLITE_NULLEQ
** otherwise: op==pExpr->op and p5==0
*/
static void codeVectorCompare(
Parse *pParse, /* Code generator context */
Expr *pExpr, /* The comparison operation */
int dest, /* Write results into this register */
u8 op, /* Comparison operator */
u8 p5 /* SQLITE_NULLEQ or zero */
){
Vdbe *v = pParse->pVdbe;
Expr *pLeft = pExpr->pLeft;
Expr *pRight = pExpr->pRight;
int nLeft = sqlite3ExprVectorSize(pLeft);
int i;
int regLeft = 0;
int regRight = 0;
u8 opx = op;
int addrDone = sqlite3VdbeMakeLabel(v);
if( nLeft!=sqlite3ExprVectorSize(pRight) ){
sqlite3ErrorMsg(pParse, "row value misused");
return;
}
assert( pExpr->op==TK_EQ || pExpr->op==TK_NE
|| pExpr->op==TK_IS || pExpr->op==TK_ISNOT
|| pExpr->op==TK_LT || pExpr->op==TK_GT
|| pExpr->op==TK_LE || pExpr->op==TK_GE
);
assert( pExpr->op==op || (pExpr->op==TK_IS && op==TK_EQ)
|| (pExpr->op==TK_ISNOT && op==TK_NE) );
assert( p5==0 || pExpr->op!=op );
assert( p5==SQLITE_NULLEQ || pExpr->op==op );
p5 |= SQLITE_STOREP2;
if( opx==TK_LE ) opx = TK_LT;
if( opx==TK_GE ) opx = TK_GT;
regLeft = exprCodeSubselect(pParse, pLeft);
regRight = exprCodeSubselect(pParse, pRight);
for(i=0; 1 /*Loop exits by "break"*/; i++){
int regFree1 = 0, regFree2 = 0;
Expr *pL, *pR;
int r1, r2;
assert( i>=0 && i<nLeft );
if( i>0 ) sqlite3ExprCachePush(pParse);
r1 = exprVectorRegister(pParse, pLeft, i, regLeft, &pL, ®Free1);
r2 = exprVectorRegister(pParse, pRight, i, regRight, &pR, ®Free2);
codeCompare(pParse, pL, pR, opx, r1, r2, dest, p5);
testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
testcase(op==OP_Eq); VdbeCoverageIf(v,op==OP_Eq);
testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
sqlite3ReleaseTempReg(pParse, regFree1);
sqlite3ReleaseTempReg(pParse, regFree2);
if( i>0 ) sqlite3ExprCachePop(pParse);
if( i==nLeft-1 ){
break;
}
if( opx==TK_EQ ){
sqlite3VdbeAddOp2(v, OP_IfNot, dest, addrDone); VdbeCoverage(v);
p5 |= SQLITE_KEEPNULL;
}else if( opx==TK_NE ){
sqlite3VdbeAddOp2(v, OP_If, dest, addrDone); VdbeCoverage(v);
p5 |= SQLITE_KEEPNULL;
}else{
assert( op==TK_LT || op==TK_GT || op==TK_LE || op==TK_GE );
sqlite3VdbeAddOp2(v, OP_ElseNotEq, 0, addrDone);
VdbeCoverageIf(v, op==TK_LT);
VdbeCoverageIf(v, op==TK_GT);
VdbeCoverageIf(v, op==TK_LE);
VdbeCoverageIf(v, op==TK_GE);
if( i==nLeft-2 ) opx = op;
}
}
sqlite3VdbeResolveLabel(v, addrDone);
}
#if SQLITE_MAX_EXPR_DEPTH>0
/*
** Check that argument nHeight is less than or equal to the maximum
** expression depth allowed. If it is not, leave an error message in
** pParse.
*/
int sqlite3ExprCheckHeight(Parse *pParse, int nHeight){
int rc = SQLITE_OK;
int mxHeight = pParse->db->aLimit[SQLITE_LIMIT_EXPR_DEPTH];
if( nHeight>mxHeight ){
sqlite3ErrorMsg(pParse,
"Expression tree is too large (maximum depth %d)", mxHeight
);
rc = SQLITE_ERROR;
}
return rc;
}
/* The following three functions, heightOfExpr(), heightOfExprList()
** and heightOfSelect(), are used to determine the maximum height
** of any expression tree referenced by the structure passed as the
** first argument.
**
** If this maximum height is greater than the current value pointed
** to by pnHeight, the second parameter, then set *pnHeight to that
** value.
*/
static void heightOfExpr(Expr *p, int *pnHeight){
if( p ){
if( p->nHeight>*pnHeight ){
*pnHeight = p->nHeight;
}
}
}
static void heightOfExprList(ExprList *p, int *pnHeight){
if( p ){
int i;
for(i=0; i<p->nExpr; i++){
heightOfExpr(p->a[i].pExpr, pnHeight);
}
}
}
static void heightOfSelect(Select *pSelect, int *pnHeight){
Select *p;
for(p=pSelect; p; p=p->pPrior){
heightOfExpr(p->pWhere, pnHeight);
heightOfExpr(p->pHaving, pnHeight);
heightOfExpr(p->pLimit, pnHeight);
heightOfExprList(p->pEList, pnHeight);
heightOfExprList(p->pGroupBy, pnHeight);
heightOfExprList(p->pOrderBy, pnHeight);
}
}
/*
** Set the Expr.nHeight variable in the structure passed as an
** argument. An expression with no children, Expr.pList or
** Expr.pSelect member has a height of 1. Any other expression
** has a height equal to the maximum height of any other
** referenced Expr plus one.
**
** Also propagate EP_Propagate flags up from Expr.x.pList to Expr.flags,
** if appropriate.
*/
static void exprSetHeight(Expr *p){
int nHeight = 0;
heightOfExpr(p->pLeft, &nHeight);
heightOfExpr(p->pRight, &nHeight);
if( ExprHasProperty(p, EP_xIsSelect) ){
heightOfSelect(p->x.pSelect, &nHeight);
}else if( p->x.pList ){
heightOfExprList(p->x.pList, &nHeight);
p->flags |= EP_Propagate & sqlite3ExprListFlags(p->x.pList);
}
p->nHeight = nHeight + 1;
}
/*
** Set the Expr.nHeight variable using the exprSetHeight() function. If
** the height is greater than the maximum allowed expression depth,
** leave an error in pParse.
**
** Also propagate all EP_Propagate flags from the Expr.x.pList into
** Expr.flags.
*/
void sqlite3ExprSetHeightAndFlags(Parse *pParse, Expr *p){
if( pParse->nErr ) return;
exprSetHeight(p);
sqlite3ExprCheckHeight(pParse, p->nHeight);
}
/*
** Return the maximum height of any expression tree referenced
** by the select statement passed as an argument.
*/
int sqlite3SelectExprHeight(Select *p){
int nHeight = 0;
heightOfSelect(p, &nHeight);
return nHeight;
}
#else /* ABOVE: Height enforcement enabled. BELOW: Height enforcement off */
/*
** Propagate all EP_Propagate flags from the Expr.x.pList into
** Expr.flags.
*/
void sqlite3ExprSetHeightAndFlags(Parse *pParse, Expr *p){
if( p && p->x.pList && !ExprHasProperty(p, EP_xIsSelect) ){
p->flags |= EP_Propagate & sqlite3ExprListFlags(p->x.pList);
}
}
#define exprSetHeight(y)
#endif /* SQLITE_MAX_EXPR_DEPTH>0 */
/*
** This routine is the core allocator for Expr nodes.
**
** Construct a new expression node and return a pointer to it. Memory
** for this node and for the pToken argument is a single allocation
** obtained from sqlite3DbMalloc(). The calling function
** is responsible for making sure the node eventually gets freed.
**
** If dequote is true, then the token (if it exists) is dequoted.
** If dequote is false, no dequoting is performed. The deQuote
** parameter is ignored if pToken is NULL or if the token does not
** appear to be quoted. If the quotes were of the form "..." (double-quotes)
** then the EP_DblQuoted flag is set on the expression node.
**
** Special case: If op==TK_INTEGER and pToken points to a string that
** can be translated into a 32-bit integer, then the token is not
** stored in u.zToken. Instead, the integer values is written
** into u.iValue and the EP_IntValue flag is set. No extra storage
** is allocated to hold the integer text and the dequote flag is ignored.
*/
Expr *sqlite3ExprAlloc(
sqlite3 *db, /* Handle for sqlite3DbMallocRawNN() */
int op, /* Expression opcode */
const Token *pToken, /* Token argument. Might be NULL */
int dequote /* True to dequote */
){
Expr *pNew;
int nExtra = 0;
int iValue = 0;
assert( db!=0 );
if( pToken ){
if( op!=TK_INTEGER || pToken->z==0
|| sqlite3GetInt32(pToken->z, &iValue)==0 ){
nExtra = pToken->n+1;
assert( iValue>=0 );
}
}
pNew = sqlite3DbMallocRawNN(db, sizeof(Expr)+nExtra);
if( pNew ){
memset(pNew, 0, sizeof(Expr));
pNew->op = (u8)op;
pNew->iAgg = -1;
if( pToken ){
if( nExtra==0 ){
pNew->flags |= EP_IntValue|EP_Leaf;
pNew->u.iValue = iValue;
}else{
pNew->u.zToken = (char*)&pNew[1];
assert( pToken->z!=0 || pToken->n==0 );
if( pToken->n ) memcpy(pNew->u.zToken, pToken->z, pToken->n);
pNew->u.zToken[pToken->n] = 0;
if( dequote && sqlite3Isquote(pNew->u.zToken[0]) ){
if( pNew->u.zToken[0]=='"' ) pNew->flags |= EP_DblQuoted;
sqlite3Dequote(pNew->u.zToken);
}
}
}
#if SQLITE_MAX_EXPR_DEPTH>0
pNew->nHeight = 1;
#endif
}
return pNew;
}
/*
** Allocate a new expression node from a zero-terminated token that has
** already been dequoted.
*/
Expr *sqlite3Expr(
sqlite3 *db, /* Handle for sqlite3DbMallocZero() (may be null) */
int op, /* Expression opcode */
const char *zToken /* Token argument. Might be NULL */
){
Token x;
x.z = zToken;
x.n = sqlite3Strlen30(zToken);
return sqlite3ExprAlloc(db, op, &x, 0);
}
/*
** Attach subtrees pLeft and pRight to the Expr node pRoot.
**
** If pRoot==NULL that means that a memory allocation error has occurred.
** In that case, delete the subtrees pLeft and pRight.
*/
void sqlite3ExprAttachSubtrees(
sqlite3 *db,
Expr *pRoot,
Expr *pLeft,
Expr *pRight
){
if( pRoot==0 ){
assert( db->mallocFailed );
sqlite3ExprDelete(db, pLeft);
sqlite3ExprDelete(db, pRight);
}else{
if( pRight ){
pRoot->pRight = pRight;
pRoot->flags |= EP_Propagate & pRight->flags;
}
if( pLeft ){
pRoot->pLeft = pLeft;
pRoot->flags |= EP_Propagate & pLeft->flags;
}
exprSetHeight(pRoot);
}
}
/*
** Allocate an Expr node which joins as many as two subtrees.
**
** One or both of the subtrees can be NULL. Return a pointer to the new
** Expr node. Or, if an OOM error occurs, set pParse->db->mallocFailed,
** free the subtrees and return NULL.
*/
Expr *sqlite3PExpr(
Parse *pParse, /* Parsing context */
int op, /* Expression opcode */
Expr *pLeft, /* Left operand */
Expr *pRight /* Right operand */
){
Expr *p;
if( op==TK_AND && pParse->nErr==0 ){
/* Take advantage of short-circuit false optimization for AND */
p = sqlite3ExprAnd(pParse->db, pLeft, pRight);
}else{
p = sqlite3DbMallocRawNN(pParse->db, sizeof(Expr));
if( p ){
memset(p, 0, sizeof(Expr));
p->op = op & TKFLG_MASK;
p->iAgg = -1;
}
sqlite3ExprAttachSubtrees(pParse->db, p, pLeft, pRight);
}
if( p ) {
sqlite3ExprCheckHeight(pParse, p->nHeight);
}
return p;
}
/*
** Add pSelect to the Expr.x.pSelect field. Or, if pExpr is NULL (due
** do a memory allocation failure) then delete the pSelect object.
*/
void sqlite3PExprAddSelect(Parse *pParse, Expr *pExpr, Select *pSelect){
if( pExpr ){
pExpr->x.pSelect = pSelect;
ExprSetProperty(pExpr, EP_xIsSelect|EP_Subquery);
sqlite3ExprSetHeightAndFlags(pParse, pExpr);
}else{
assert( pParse->db->mallocFailed );
sqlite3SelectDelete(pParse->db, pSelect);
}
}
/*
** If the expression is always either TRUE or FALSE (respectively),
** then return 1. If one cannot determine the truth value of the
** expression at compile-time return 0.
**
** This is an optimization. If is OK to return 0 here even if
** the expression really is always false or false (a false negative).
** But it is a bug to return 1 if the expression might have different
** boolean values in different circumstances (a false positive.)
**
** Note that if the expression is part of conditional for a
** LEFT JOIN, then we cannot determine at compile-time whether or not
** is it true or false, so always return 0.
*/
static int exprAlwaysTrue(Expr *p){
int v = 0;
if( ExprHasProperty(p, EP_FromJoin) ) return 0;
if( !sqlite3ExprIsInteger(p, &v) ) return 0;
return v!=0;
}
static int exprAlwaysFalse(Expr *p){
int v = 0;
if( ExprHasProperty(p, EP_FromJoin) ) return 0;
if( !sqlite3ExprIsInteger(p, &v) ) return 0;
return v==0;
}
/*
** Join two expressions using an AND operator. If either expression is
** NULL, then just return the other expression.
**
** If one side or the other of the AND is known to be false, then instead
** of returning an AND expression, just return a constant expression with
** a value of false.
*/
Expr *sqlite3ExprAnd(sqlite3 *db, Expr *pLeft, Expr *pRight){
if( pLeft==0 ){
return pRight;
}else if( pRight==0 ){
return pLeft;
}else if( exprAlwaysFalse(pLeft) || exprAlwaysFalse(pRight) ){
sqlite3ExprDelete(db, pLeft);
sqlite3ExprDelete(db, pRight);
return sqlite3ExprAlloc(db, TK_INTEGER, &sqlite3IntTokens[0], 0);
}else{
Expr *pNew = sqlite3ExprAlloc(db, TK_AND, 0, 0);
sqlite3ExprAttachSubtrees(db, pNew, pLeft, pRight);
return pNew;
}
}
/*
** Construct a new expression node for a function with multiple
** arguments.
*/
Expr *sqlite3ExprFunction(Parse *pParse, ExprList *pList, Token *pToken){
Expr *pNew;
sqlite3 *db = pParse->db;
assert( pToken );
pNew = sqlite3ExprAlloc(db, TK_FUNCTION, pToken, 1);
if( pNew==0 ){
sqlite3ExprListDelete(db, pList); /* Avoid memory leak when malloc fails */
return 0;
}
pNew->x.pList = pList;
ExprSetProperty(pNew, EP_HasFunc);
assert( !ExprHasProperty(pNew, EP_xIsSelect) );
sqlite3ExprSetHeightAndFlags(pParse, pNew);
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 big to avoid a denial of service attack when
** the SQL statement comes from an external source.
**
** Wildcards of the form ":aaa", "@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 sequential variable number is
** assigned.
*/
void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr, u32 n){
sqlite3 *db = pParse->db;
const char *z;
ynVar x;
if( pExpr==0 ) return;
assert( !ExprHasProperty(pExpr, EP_IntValue|EP_Reduced|EP_TokenOnly) );
z = pExpr->u.zToken;
assert( z!=0 );
assert( z[0]!=0 );
assert( n==(u32)sqlite3Strlen30(z) );
if( z[1]==0 ){
/* Wildcard of the form "?". Assign the next variable number */
assert( z[0]=='?' );
x = (ynVar)(++pParse->nVar);
}else{
int doAdd = 0;
if( z[0]=='?' ){
/* Wildcard of the form "?nnn". Convert "nnn" to an integer and
** use it as the variable number */
i64 i;
int bOk;
if( n==2 ){ /*OPTIMIZATION-IF-TRUE*/
i = z[1]-'0'; /* The common case of ?N for a single digit N */
bOk = 1;