expr.c

sqlite 嵌入式数据库的源码

  }

  switch( pExpr->op ){
    case TK_IN: {
      char affinity;
      KeyInfo keyInfo;
      int addr;        /* Address of OP_OpenTemp instruction */

      affinity = sqlite3ExprAffinity(pExpr->pLeft);

      /* Whether this is an 'x IN(SELECT...)' or an 'x IN(<exprlist>)'
      ** expression it is handled the same way. A temporary table is 
      ** filled with single-field index keys representing the results
      ** from the SELECT or the <exprlist>.
      **
      ** If the 'x' expression is a column value, or the SELECT...
      ** statement returns a column value, then the affinity of that
      ** column is used to build the index keys. If both 'x' and the
      ** SELECT... statement are columns, then numeric affinity is used
      ** if either column has NUMERIC or INTEGER affinity. If neither
      ** 'x' nor the SELECT... statement are columns, then numeric affinity
      ** is used.
      */
      pExpr->iTable = pParse->nTab++;
      addr = sqlite3VdbeAddOp(v, OP_OpenTemp, pExpr->iTable, 0);
      memset(&keyInfo, 0, sizeof(keyInfo));
      keyInfo.nField = 1;
      sqlite3VdbeAddOp(v, OP_SetNumColumns, pExpr->iTable, 1);

      if( pExpr->pSelect ){
        /* Case 1:     expr IN (SELECT ...)
        **
        ** Generate code to write the results of the select into the temporary
        ** table allocated and opened above.
        */
        int iParm = pExpr->iTable +  (((int)affinity)<<16);
        ExprList *pEList;
        assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
        sqlite3Select(pParse, pExpr->pSelect, SRT_Set, iParm, 0, 0, 0, 0);
        pEList = pExpr->pSelect->pEList;
        if( pEList && pEList->nExpr>0 ){ 
          keyInfo.aColl[0] = binaryCompareCollSeq(pParse, pExpr->pLeft,
              pEList->a[0].pExpr);
        }
      }else if( pExpr->pList ){
        /* Case 2:     expr IN (exprlist)
        **
	** For each expression, build an index key from the evaluation and
        ** store it in the temporary table. If <expr> is a column, then use
        ** that columns affinity when building index keys. If <expr> is not
        ** a column, use numeric affinity.
        */
        int i;
        if( !affinity ){
          affinity = SQLITE_AFF_NUMERIC;
        }
        keyInfo.aColl[0] = pExpr->pLeft->pColl;

        /* Loop through each expression in <exprlist>. */
        for(i=0; i<pExpr->pList->nExpr; i++){
          Expr *pE2 = pExpr->pList->a[i].pExpr;

          /* Check that the expression is constant and valid. */
          if( !sqlite3ExprIsConstant(pE2) ){
            sqlite3ErrorMsg(pParse,
              "right-hand side of IN operator must be constant");
            return;
          }

          /* Evaluate the expression and insert it into the temp table */
          sqlite3ExprCode(pParse, pE2);
          sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &affinity, 1);
          sqlite3VdbeAddOp(v, OP_IdxInsert, pExpr->iTable, 0);
        }
      }
      sqlite3VdbeChangeP3(v, addr, (void *)&keyInfo, P3_KEYINFO);
      break;
    }

    case TK_EXISTS:
    case TK_SELECT: {
      /* This has to be a scalar SELECT.  Generate code to put the
      ** value of this select in a memory cell and record the number
      ** of the memory cell in iColumn.
      */
      int sop;
      Select *pSel;

      pExpr->iColumn = pParse->nMem++;
      pSel = pExpr->pSelect;
      if( pExpr->op==TK_SELECT ){
        sop = SRT_Mem;
      }else{
        static const Token one = { "1", 0, 1 };
        sop = SRT_Exists;
        sqlite3ExprListDelete(pSel->pEList);
        pSel->pEList = sqlite3ExprListAppend(0, 
                          sqlite3Expr(TK_INTEGER, 0, 0, &one), 0);
      }
      sqlite3Select(pParse, pSel, sop, pExpr->iColumn, 0, 0, 0, 0);
      break;
    }
  }

  if( pExpr->pSelect ){
    sqlite3VdbeAddOp(v, OP_AggContextPop, 0, 0);
  }
  if( label<0 ){
    sqlite3VdbeResolveLabel(v, label);
  }
  return;
}
#endif /* SQLITE_OMIT_SUBQUERY */

/*
** Generate an instruction that will put the integer describe by
** text z[0..n-1] on the stack.
*/
static void codeInteger(Vdbe *v, const char *z, int n){
  int i;
  if( sqlite3GetInt32(z, &i) ){
    sqlite3VdbeAddOp(v, OP_Integer, i, 0);
  }else if( sqlite3FitsIn64Bits(z) ){
    sqlite3VdbeOp3(v, OP_Integer, 0, 0, z, n);
  }else{
    sqlite3VdbeOp3(v, OP_Real, 0, 0, z, n);
  }
}

/*
** Generate code into the current Vdbe to evaluate the given
** expression and leave the result on the top of stack.
**
** This code depends on the fact that certain token values (ex: TK_EQ)
** are the same as opcode values (ex: OP_Eq) that implement the corresponding
** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
** the make process cause these values to align.  Assert()s in the code
** below verify that the numbers are aligned correctly.
*/
void sqlite3ExprCode(Parse *pParse, Expr *pExpr){
  Vdbe *v = pParse->pVdbe;
  int op;
  if( v==0 ) return;
  if( pExpr==0 ){
    sqlite3VdbeAddOp(v, OP_Null, 0, 0);
    return;
  }
  op = pExpr->op;
  switch( op ){
    case TK_COLUMN: {
      if( !pParse->fillAgg && pExpr->iAgg>=0 ){
        sqlite3VdbeAddOp(v, OP_AggGet, pExpr->iAggCtx, pExpr->iAgg);
      }else if( pExpr->iColumn>=0 ){
        sqlite3VdbeAddOp(v, OP_Column, pExpr->iTable, pExpr->iColumn);
        sqlite3ColumnDefault(v, pExpr->pTab, pExpr->iColumn);
      }else{
        sqlite3VdbeAddOp(v, OP_Rowid, pExpr->iTable, 0);
      }
      break;
    }
    case TK_INTEGER: {
      codeInteger(v, pExpr->token.z, pExpr->token.n);
      break;
    }
    case TK_FLOAT:
    case TK_STRING: {
      assert( TK_FLOAT==OP_Real );
      assert( TK_STRING==OP_String8 );
      sqlite3VdbeOp3(v, op, 0, 0, pExpr->token.z, pExpr->token.n);
      sqlite3VdbeDequoteP3(v, -1);
      break;
    }
    case TK_NULL: {
      sqlite3VdbeAddOp(v, OP_Null, 0, 0);
      break;
    }
#ifndef SQLITE_OMIT_BLOB_LITERAL
    case TK_BLOB: {
      assert( TK_BLOB==OP_HexBlob );
      sqlite3VdbeOp3(v, op, 0, 0, pExpr->token.z+1, pExpr->token.n-1);
      sqlite3VdbeDequoteP3(v, -1);
      break;
    }
#endif
    case TK_VARIABLE: {
      sqlite3VdbeAddOp(v, OP_Variable, pExpr->iTable, 0);
      if( pExpr->token.n>1 ){
        sqlite3VdbeChangeP3(v, -1, pExpr->token.z, pExpr->token.n);
      }
      break;
    }
    case TK_REGISTER: {
      sqlite3VdbeAddOp(v, OP_MemLoad, pExpr->iTable, 0);
      break;
    }
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {
      assert( TK_LT==OP_Lt );
      assert( TK_LE==OP_Le );
      assert( TK_GT==OP_Gt );
      assert( TK_GE==OP_Ge );
      assert( TK_EQ==OP_Eq );
      assert( TK_NE==OP_Ne );
      sqlite3ExprCode(pParse, pExpr->pLeft);
      sqlite3ExprCode(pParse, pExpr->pRight);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, 0, 0);
      break;
    }
    case TK_AND:
    case TK_OR:
    case TK_PLUS:
    case TK_STAR:
    case TK_MINUS:
    case TK_REM:
    case TK_BITAND:
    case TK_BITOR:
    case TK_SLASH:
    case TK_LSHIFT:
    case TK_RSHIFT: 
    case TK_CONCAT: {
      assert( TK_AND==OP_And );
      assert( TK_OR==OP_Or );
      assert( TK_PLUS==OP_Add );
      assert( TK_MINUS==OP_Subtract );
      assert( TK_REM==OP_Remainder );
      assert( TK_BITAND==OP_BitAnd );
      assert( TK_BITOR==OP_BitOr );
      assert( TK_SLASH==OP_Divide );
      assert( TK_LSHIFT==OP_ShiftLeft );
      assert( TK_RSHIFT==OP_ShiftRight );
      assert( TK_CONCAT==OP_Concat );
      sqlite3ExprCode(pParse, pExpr->pLeft);
      sqlite3ExprCode(pParse, pExpr->pRight);
      sqlite3VdbeAddOp(v, op, 0, 0);
      break;
    }
    case TK_UMINUS: {
      Expr *pLeft = pExpr->pLeft;
      assert( pLeft );
      if( pLeft->op==TK_FLOAT || pLeft->op==TK_INTEGER ){
        Token *p = &pLeft->token;
        char *z = sqliteMalloc( p->n + 2 );
        sprintf(z, "-%.*s", p->n, p->z);
        if( pLeft->op==TK_FLOAT ){
          sqlite3VdbeOp3(v, OP_Real, 0, 0, z, p->n+1);
        }else{
          codeInteger(v, z, p->n+1);
        }
        sqliteFree(z);
        break;
      }
      /* Fall through into TK_NOT */
    }
    case TK_BITNOT:
    case TK_NOT: {
      assert( TK_BITNOT==OP_BitNot );
      assert( TK_NOT==OP_Not );
      sqlite3ExprCode(pParse, pExpr->pLeft);
      sqlite3VdbeAddOp(v, op, 0, 0);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      int dest;
      assert( TK_ISNULL==OP_IsNull );
      assert( TK_NOTNULL==OP_NotNull );
      sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
      sqlite3ExprCode(pParse, pExpr->pLeft);
      dest = sqlite3VdbeCurrentAddr(v) + 2;
      sqlite3VdbeAddOp(v, op, 1, dest);
      sqlite3VdbeAddOp(v, OP_AddImm, -1, 0);
      break;
    }
    case TK_AGG_FUNCTION: {
      sqlite3VdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg);
      break;
    }
    case TK_CONST_FUNC:
    case TK_FUNCTION: {
      ExprList *pList = pExpr->pList;
      int nExpr = pList ? pList->nExpr : 0;
      FuncDef *pDef;
      int nId;
      const char *zId;
      int p2 = 0;
      int i;
      u8 enc = pParse->db->enc;
      CollSeq *pColl = 0;
      zId = pExpr->token.z;
      nId = pExpr->token.n;
      pDef = sqlite3FindFunction(pParse->db, zId, nId, nExpr, enc, 0);
      assert( pDef!=0 );
      nExpr = sqlite3ExprCodeExprList(pParse, pList);
      for(i=0; i<nExpr && i<32; i++){
        if( sqlite3ExprIsConstant(pList->a[i].pExpr) ){
          p2 |= (1<<i);
        }
        if( pDef->needCollSeq && !pColl ){
          pColl = sqlite3ExprCollSeq(pParse, pList->a[i].pExpr);
        }
      }
      if( pDef->needCollSeq ){
        if( !pColl ) pColl = pParse->db->pDfltColl; 
        sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
      }
      sqlite3VdbeOp3(v, OP_Function, nExpr, p2, (char*)pDef, P3_FUNCDEF);
      break;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_EXISTS:
    case TK_SELECT: {
      sqlite3CodeSubselect(pParse, pExpr);
      sqlite3VdbeAddOp(v, OP_MemLoad, pExpr->iColumn, 0);
      VdbeComment((v, "# load subquery result"));
      break;
    }
    case TK_IN: {
      int addr;
      char affinity;
      sqlite3CodeSubselect(pParse, pExpr);

      /* Figure out the affinity to use to create a key from the results
      ** of the expression. affinityStr stores a static string suitable for
      ** P3 of OP_MakeRecord.
      */
      affinity = comparisonAffinity(pExpr);

      sqlite3VdbeAddOp(v, OP_Integer, 1, 0);

      /* Code the <expr> from "<expr> IN (...)". The temporary table
      ** pExpr->iTable contains the values that make up the (...) set.
      */
      sqlite3ExprCode(pParse, pExpr->pLeft);
      addr = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_NotNull, -1, addr+4);            /* addr + 0 */
      sqlite3VdbeAddOp(v, OP_Pop, 2, 0);
      sqlite3VdbeAddOp(v, OP_Null, 0, 0);
      sqlite3VdbeAddOp(v, OP_Goto, 0, addr+7);
      sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &affinity, 1);   /* addr + 4 */
      sqlite3VdbeAddOp(v, OP_Found, pExpr->iTable, addr+7);
      sqlite3VdbeAddOp(v, OP_AddImm, -1, 0);                  /* addr + 6 */

      break;
    }
#endif
    case TK_BETWEEN: {
      Expr *pLeft = pExpr->pLeft;
      struct ExprList_item *pLItem = pExpr->pList->a;
      Expr *pRight = pLItem->pExpr;
      sqlite3ExprCode(pParse, pLeft);
      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
      sqlite3ExprCode(pParse, pRight);
      codeCompare(pParse, pLeft, pRight, OP_Ge, 0, 0);
      sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
      pLItem++;
      pRight = pLItem->pExpr;
      sqlite3ExprCode(pParse, pRight);
      codeCompare(pParse, pLeft, pRight, OP_Le, 0, 0);
      sqlite3VdbeAddOp(v, OP_And, 0, 0);
      break;
    }
    case TK_UPLUS:
    case TK_AS: {
      sqlite3ExprCode(pParse, pExpr->pLeft);
      break;
    }
    case TK_CASE: {
      int expr_end_label;
      int jumpInst;
      int addr;
      int nExpr;
      int i;
      ExprList *pEList;
      struct ExprList_item *aListelem;

      assert(pExpr->pList);
      assert((pExpr->pList->nExpr % 2) == 0);
      assert(pExpr->pList->nExpr > 0);
      pEList = pExpr->pList;
      aListelem = pEList->a;
      nExpr = pEList->nExpr;
      expr_end_label = sqlite3VdbeMakeLabel(v);
      if( pExpr->pLeft ){
        sqlite3ExprCode(pParse, pExpr->pLeft);
      }
      for(i=0; i<nExpr; i=i+2){
        sqlite3ExprCode(pParse, aListelem[i].pExpr);
        if( pExpr->pLeft ){
          sqlite3VdbeAddOp(v, OP_Dup, 1, 1);
          jumpInst = codeCompare(pParse, pExpr->pLeft, aListelem[i].pExpr,
                                 OP_Ne, 0, 1);
          sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
        }else{
          jumpInst = sqlite3VdbeAddOp(v, OP_IfNot, 1, 0);
        }
        sqlite3ExprCode(pParse, aListelem[i+1].pExpr);
        sqlite3VdbeAddOp(v, OP_Goto, 0, expr_end_label);
        addr = sqlite3VdbeCurrentAddr(v);
        sqlite3VdbeChangeP2(v, jumpInst, addr);
      }
      if( pExpr->pLeft ){
        sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
      }
      if( pExpr->pRight ){
        sqlite3ExprCode(pParse, pExpr->pRight);
      }else{
        sqlite3VdbeAddOp(v, OP_Null, 0, 0);
      }
      sqlite3VdbeResolveLabel(v, expr_end_label);