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postgres/src/backend/parser/parse_expr.c
Tom Lane a9545b3aef Improve UPDATE/DELETE WHERE CURRENT OF so that they can be used from plpgsql 
with a plpgsql-defined cursor.  The underlying mechanism for this is that the
main SQL engine will now take "WHERE CURRENT OF $n" where $n is a refcursor
parameter.  Not sure if we should document that fact or consider it an
implementation detail.  Per discussion with Pavel Stehule.
2007-06-11 22:22:42 +00:00

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/*-------------------------------------------------------------------------
*
* parse_expr.c
* handle expressions in parser
*
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.220 2007/06/11 22:22:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/pg_type.h"
#include "commands/dbcommands.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/plannodes.h"
#include "optimizer/clauses.h"
#include "parser/analyze.h"
#include "parser/gramparse.h"
#include "parser/parse_coerce.h"
#include "parser/parse_expr.h"
#include "parser/parse_func.h"
#include "parser/parse_oper.h"
#include "parser/parse_relation.h"
#include "parser/parse_target.h"
#include "parser/parse_type.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/xml.h"
bool Transform_null_equals = false;
static Node *transformParamRef(ParseState *pstate, ParamRef *pref);
static Node *transformAExprOp(ParseState *pstate, A_Expr *a);
static Node *transformAExprAnd(ParseState *pstate, A_Expr *a);
static Node *transformAExprOr(ParseState *pstate, A_Expr *a);
static Node *transformAExprNot(ParseState *pstate, A_Expr *a);
static Node *transformAExprOpAny(ParseState *pstate, A_Expr *a);
static Node *transformAExprOpAll(ParseState *pstate, A_Expr *a);
static Node *transformAExprDistinct(ParseState *pstate, A_Expr *a);
static Node *transformAExprNullIf(ParseState *pstate, A_Expr *a);
static Node *transformAExprOf(ParseState *pstate, A_Expr *a);
static Node *transformAExprIn(ParseState *pstate, A_Expr *a);
static Node *transformFuncCall(ParseState *pstate, FuncCall *fn);
static Node *transformCaseExpr(ParseState *pstate, CaseExpr *c);
static Node *transformSubLink(ParseState *pstate, SubLink *sublink);
static Node *transformArrayExpr(ParseState *pstate, ArrayExpr *a);
static Node *transformRowExpr(ParseState *pstate, RowExpr *r);
static Node *transformCoalesceExpr(ParseState *pstate, CoalesceExpr *c);
static Node *transformMinMaxExpr(ParseState *pstate, MinMaxExpr *m);
static Node *transformXmlExpr(ParseState *pstate, XmlExpr *x);
static Node *transformXmlSerialize(ParseState *pstate, XmlSerialize *xs);
static Node *transformBooleanTest(ParseState *pstate, BooleanTest *b);
static Node *transformCurrentOfExpr(ParseState *pstate, CurrentOfExpr *cexpr);
static Node *transformColumnRef(ParseState *pstate, ColumnRef *cref);
static Node *transformWholeRowRef(ParseState *pstate, char *schemaname,
char *relname, int location);
static Node *transformIndirection(ParseState *pstate, Node *basenode,
List *indirection);
static Node *typecast_expression(ParseState *pstate, Node *expr,
TypeName *typename);
static Node *make_row_comparison_op(ParseState *pstate, List *opname,
List *largs, List *rargs, int location);
static Node *make_row_distinct_op(ParseState *pstate, List *opname,
RowExpr *lrow, RowExpr *rrow, int location);
static Expr *make_distinct_op(ParseState *pstate, List *opname,
Node *ltree, Node *rtree, int location);
/*
* transformExpr -
* Analyze and transform expressions. Type checking and type casting is
* done here. The optimizer and the executor cannot handle the original
* (raw) expressions collected by the parse tree. Hence the transformation
* here.
*
* NOTE: there are various cases in which this routine will get applied to
* an already-transformed expression. Some examples:
* 1. At least one construct (BETWEEN/AND) puts the same nodes
* into two branches of the parse tree; hence, some nodes
* are transformed twice.
* 2. Another way it can happen is that coercion of an operator or
* function argument to the required type (via coerce_type())
* can apply transformExpr to an already-transformed subexpression.
* An example here is "SELECT count(*) + 1.0 FROM table".
* While it might be possible to eliminate these cases, the path of
* least resistance so far has been to ensure that transformExpr() does
* no damage if applied to an already-transformed tree. This is pretty
* easy for cases where the transformation replaces one node type with
* another, such as A_Const => Const; we just do nothing when handed
* a Const. More care is needed for node types that are used as both
* input and output of transformExpr; see SubLink for example.
*/
Node *
transformExpr(ParseState *pstate, Node *expr)
{
Node *result = NULL;
if (expr == NULL)
return NULL;
/* Guard against stack overflow due to overly complex expressions */
check_stack_depth();
switch (nodeTag(expr))
{
case T_ColumnRef:
result = transformColumnRef(pstate, (ColumnRef *) expr);
break;
case T_ParamRef:
result = transformParamRef(pstate, (ParamRef *) expr);
break;
case T_A_Const:
{
A_Const *con = (A_Const *) expr;
Value *val = &con->val;
result = (Node *) make_const(val);
if (con->typename != NULL)
result = typecast_expression(pstate, result,
con->typename);
break;
}
case T_A_Indirection:
{
A_Indirection *ind = (A_Indirection *) expr;
result = transformExpr(pstate, ind->arg);
result = transformIndirection(pstate, result,
ind->indirection);
break;
}
case T_TypeCast:
{
TypeCast *tc = (TypeCast *) expr;
Node *arg = transformExpr(pstate, tc->arg);
result = typecast_expression(pstate, arg, tc->typename);
break;
}
case T_A_Expr:
{
A_Expr *a = (A_Expr *) expr;
switch (a->kind)
{
case AEXPR_OP:
result = transformAExprOp(pstate, a);
break;
case AEXPR_AND:
result = transformAExprAnd(pstate, a);
break;
case AEXPR_OR:
result = transformAExprOr(pstate, a);
break;
case AEXPR_NOT:
result = transformAExprNot(pstate, a);
break;
case AEXPR_OP_ANY:
result = transformAExprOpAny(pstate, a);
break;
case AEXPR_OP_ALL:
result = transformAExprOpAll(pstate, a);
break;
case AEXPR_DISTINCT:
result = transformAExprDistinct(pstate, a);
break;
case AEXPR_NULLIF:
result = transformAExprNullIf(pstate, a);
break;
case AEXPR_OF:
result = transformAExprOf(pstate, a);
break;
case AEXPR_IN:
result = transformAExprIn(pstate, a);
break;
default:
elog(ERROR, "unrecognized A_Expr kind: %d", a->kind);
}
break;
}
case T_FuncCall:
result = transformFuncCall(pstate, (FuncCall *) expr);
break;
case T_SubLink:
result = transformSubLink(pstate, (SubLink *) expr);
break;
case T_CaseExpr:
result = transformCaseExpr(pstate, (CaseExpr *) expr);
break;
case T_ArrayExpr:
result = transformArrayExpr(pstate, (ArrayExpr *) expr);
break;
case T_RowExpr:
result = transformRowExpr(pstate, (RowExpr *) expr);
break;
case T_CoalesceExpr:
result = transformCoalesceExpr(pstate, (CoalesceExpr *) expr);
break;
case T_MinMaxExpr:
result = transformMinMaxExpr(pstate, (MinMaxExpr *) expr);
break;
case T_XmlExpr:
result = transformXmlExpr(pstate, (XmlExpr *) expr);
break;
case T_XmlSerialize:
result = transformXmlSerialize(pstate, (XmlSerialize *) expr);
break;
case T_NullTest:
{
NullTest *n = (NullTest *) expr;
n->arg = (Expr *) transformExpr(pstate, (Node *) n->arg);
/* the argument can be any type, so don't coerce it */
result = expr;
break;
}
case T_BooleanTest:
result = transformBooleanTest(pstate, (BooleanTest *) expr);
break;
case T_CurrentOfExpr:
result = transformCurrentOfExpr(pstate, (CurrentOfExpr *) expr);
break;
/*********************************************
* Quietly accept node types that may be presented when we are
* called on an already-transformed tree.
*
* Do any other node types need to be accepted? For now we are
* taking a conservative approach, and only accepting node
* types that are demonstrably necessary to accept.
*********************************************/
case T_Var:
case T_Const:
case T_Param:
case T_Aggref:
case T_ArrayRef:
case T_FuncExpr:
case T_OpExpr:
case T_DistinctExpr:
case T_ScalarArrayOpExpr:
case T_NullIfExpr:
case T_BoolExpr:
case T_FieldSelect:
case T_FieldStore:
case T_RelabelType:
case T_CoerceViaIO:
case T_ArrayCoerceExpr:
case T_ConvertRowtypeExpr:
case T_CaseTestExpr:
case T_CoerceToDomain:
case T_CoerceToDomainValue:
case T_SetToDefault:
{
result = (Node *) expr;
break;
}
default:
/* should not reach here */
elog(ERROR, "unrecognized node type: %d", (int) nodeTag(expr));
break;
}
return result;
}
static Node *
transformIndirection(ParseState *pstate, Node *basenode, List *indirection)
{
Node *result = basenode;
List *subscripts = NIL;
ListCell *i;
/*
* We have to split any field-selection operations apart from
* subscripting. Adjacent A_Indices nodes have to be treated as a single
* multidimensional subscript operation.
*/
foreach(i, indirection)
{
Node *n = lfirst(i);
if (IsA(n, A_Indices))
subscripts = lappend(subscripts, n);
else
{
Assert(IsA(n, String));
/* process subscripts before this field selection */
if (subscripts)
result = (Node *) transformArraySubscripts(pstate,
result,
exprType(result),
InvalidOid,
exprTypmod(result),
subscripts,
NULL);
subscripts = NIL;
result = ParseFuncOrColumn(pstate,
list_make1(n),
list_make1(result),
false, false, true,
-1);
}
}
/* process trailing subscripts, if any */
if (subscripts)
result = (Node *) transformArraySubscripts(pstate,
result,
exprType(result),
InvalidOid,
exprTypmod(result),
subscripts,
NULL);
return result;
}
static Node *
transformColumnRef(ParseState *pstate, ColumnRef *cref)
{
int numnames = list_length(cref->fields);
Node *node;
int levels_up;
/*----------
* The allowed syntaxes are:
*
* A First try to resolve as unqualified column name;
* if no luck, try to resolve as unqualified table name (A.*).
* A.B A is an unqualified table name; B is either a
* column or function name (trying column name first).
* A.B.C schema A, table B, col or func name C.
* A.B.C.D catalog A, schema B, table C, col or func D.
* A.* A is an unqualified table name; means whole-row value.
* A.B.* whole-row value of table B in schema A.
* A.B.C.* whole-row value of table C in schema B in catalog A.
*
* We do not need to cope with bare "*"; that will only be accepted by
* the grammar at the top level of a SELECT list, and transformTargetList
* will take care of it before it ever gets here. Also, "A.*" etc will
* be expanded by transformTargetList if they appear at SELECT top level,
* so here we are only going to see them as function or operator inputs.
*
* Currently, if a catalog name is given then it must equal the current
* database name; we check it here and then discard it.
*----------
*/
switch (numnames)
{
case 1:
{
char *name = strVal(linitial(cref->fields));
/* Try to identify as an unqualified column */
node = colNameToVar(pstate, name, false, cref->location);
if (node == NULL)
{
/*
* Not known as a column of any range-table entry.
*
* Consider the possibility that it's VALUE in a domain
* check expression. (We handle VALUE as a name, not a
* keyword, to avoid breaking a lot of applications that
* have used VALUE as a column name in the past.)
*/
if (pstate->p_value_substitute != NULL &&
strcmp(name, "value") == 0)
{
node = (Node *) copyObject(pstate->p_value_substitute);
break;
}
/*
* Try to find the name as a relation. Note that only
* relations already entered into the rangetable will be
* recognized.
*
* This is a hack for backwards compatibility with
* PostQUEL-inspired syntax. The preferred form now is
* "rel.*".
*/
if (refnameRangeTblEntry(pstate, NULL, name,
&levels_up) != NULL)
node = transformWholeRowRef(pstate, NULL, name,
cref->location);
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" does not exist",
name),
parser_errposition(pstate, cref->location)));
}
break;
}
case 2:
{
char *name1 = strVal(linitial(cref->fields));
char *name2 = strVal(lsecond(cref->fields));
/* Whole-row reference? */
if (strcmp(name2, "*") == 0)
{
node = transformWholeRowRef(pstate, NULL, name1,
cref->location);
break;
}
/* Try to identify as a once-qualified column */
node = qualifiedNameToVar(pstate, NULL, name1, name2, true,
cref->location);
if (node == NULL)
{
/*
* Not known as a column of any range-table entry, so try
* it as a function call. Here, we will create an
* implicit RTE for tables not already entered.
*/
node = transformWholeRowRef(pstate, NULL, name1,
cref->location);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(name2)),
list_make1(node),
false, false, true,
cref->location);
}
break;
}
case 3:
{
char *name1 = strVal(linitial(cref->fields));
char *name2 = strVal(lsecond(cref->fields));
char *name3 = strVal(lthird(cref->fields));
/* Whole-row reference? */
if (strcmp(name3, "*") == 0)
{
node = transformWholeRowRef(pstate, name1, name2,
cref->location);
break;
}
/* Try to identify as a twice-qualified column */
node = qualifiedNameToVar(pstate, name1, name2, name3, true,
cref->location);
if (node == NULL)
{
/* Try it as a function call */
node = transformWholeRowRef(pstate, name1, name2,
cref->location);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(name3)),
list_make1(node),
false, false, true,
cref->location);
}
break;
}
case 4:
{
char *name1 = strVal(linitial(cref->fields));
char *name2 = strVal(lsecond(cref->fields));
char *name3 = strVal(lthird(cref->fields));
char *name4 = strVal(lfourth(cref->fields));
/*
* We check the catalog name and then ignore it.
*/
if (strcmp(name1, get_database_name(MyDatabaseId)) != 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cross-database references are not implemented: %s",
NameListToString(cref->fields)),
parser_errposition(pstate, cref->location)));
/* Whole-row reference? */
if (strcmp(name4, "*") == 0)
{
node = transformWholeRowRef(pstate, name2, name3,
cref->location);
break;
}
/* Try to identify as a twice-qualified column */
node = qualifiedNameToVar(pstate, name2, name3, name4, true,
cref->location);
if (node == NULL)
{
/* Try it as a function call */
node = transformWholeRowRef(pstate, name2, name3,
cref->location);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(name4)),
list_make1(node),
false, false, true,
cref->location);
}
break;
}
default:
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("improper qualified name (too many dotted names): %s",
NameListToString(cref->fields)),
parser_errposition(pstate, cref->location)));
node = NULL; /* keep compiler quiet */
break;
}
return node;
}
/*
* Locate the parameter type info for the given parameter number, and
* return a pointer to it.
*/
static Oid *
find_param_type(ParseState *pstate, int paramno)
{
Oid *result;
/*
* Find topmost ParseState, which is where paramtype info lives.
*/
while (pstate->parentParseState != NULL)
pstate = pstate->parentParseState;
/* Check parameter number is in range */
if (paramno <= 0) /* probably can't happen? */
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_PARAMETER),
errmsg("there is no parameter $%d", paramno)));
if (paramno > pstate->p_numparams)
{
if (!pstate->p_variableparams)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_PARAMETER),
errmsg("there is no parameter $%d",
paramno)));
/* Okay to enlarge param array */
if (pstate->p_paramtypes)
pstate->p_paramtypes = (Oid *) repalloc(pstate->p_paramtypes,
paramno * sizeof(Oid));
else
pstate->p_paramtypes = (Oid *) palloc(paramno * sizeof(Oid));
/* Zero out the previously-unreferenced slots */
MemSet(pstate->p_paramtypes + pstate->p_numparams,
0,
(paramno - pstate->p_numparams) * sizeof(Oid));
pstate->p_numparams = paramno;
}
result = &pstate->p_paramtypes[paramno - 1];
if (pstate->p_variableparams)
{
/* If not seen before, initialize to UNKNOWN type */
if (*result == InvalidOid)
*result = UNKNOWNOID;
}
return result;
}
static Node *
transformParamRef(ParseState *pstate, ParamRef *pref)
{
int paramno = pref->number;
Oid *pptype = find_param_type(pstate, paramno);
Param *param;
param = makeNode(Param);
param->paramkind = PARAM_EXTERN;
param->paramid = paramno;
param->paramtype = *pptype;
param->paramtypmod = -1;
return (Node *) param;
}
static Node *
transformAExprOp(ParseState *pstate, A_Expr *a)
{
Node *lexpr = a->lexpr;
Node *rexpr = a->rexpr;
Node *result;
/*
* Special-case "foo = NULL" and "NULL = foo" for compatibility with
* standards-broken products (like Microsoft's). Turn these into IS NULL
* exprs.
*/
if (Transform_null_equals &&
list_length(a->name) == 1 &&
strcmp(strVal(linitial(a->name)), "=") == 0 &&
(exprIsNullConstant(lexpr) || exprIsNullConstant(rexpr)))
{
NullTest *n = makeNode(NullTest);
n->nulltesttype = IS_NULL;
if (exprIsNullConstant(lexpr))
n->arg = (Expr *) rexpr;
else
n->arg = (Expr *) lexpr;
result = transformExpr(pstate, (Node *) n);
}
else if (lexpr && IsA(lexpr, RowExpr) &&
rexpr && IsA(rexpr, SubLink) &&
((SubLink *) rexpr)->subLinkType == EXPR_SUBLINK)
{
/*
* Convert "row op subselect" into a ROWCOMPARE sublink. Formerly the
* grammar did this, but now that a row construct is allowed anywhere
* in expressions, it's easier to do it here.
*/
SubLink *s = (SubLink *) rexpr;
s->subLinkType = ROWCOMPARE_SUBLINK;
s->testexpr = lexpr;
s->operName = a->name;
result = transformExpr(pstate, (Node *) s);
}
else if (lexpr && IsA(lexpr, RowExpr) &&
rexpr && IsA(rexpr, RowExpr))
{
/* "row op row" */
lexpr = transformExpr(pstate, lexpr);
rexpr = transformExpr(pstate, rexpr);
Assert(IsA(lexpr, RowExpr));
Assert(IsA(rexpr, RowExpr));
result = make_row_comparison_op(pstate,
a->name,
((RowExpr *) lexpr)->args,
((RowExpr *) rexpr)->args,
a->location);
}
else
{
/* Ordinary scalar operator */
lexpr = transformExpr(pstate, lexpr);
rexpr = transformExpr(pstate, rexpr);
result = (Node *) make_op(pstate,
a->name,
lexpr,
rexpr,
a->location);
}
return result;
}
static Node *
transformAExprAnd(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExpr(pstate, a->lexpr);
Node *rexpr = transformExpr(pstate, a->rexpr);
lexpr = coerce_to_boolean(pstate, lexpr, "AND");
rexpr = coerce_to_boolean(pstate, rexpr, "AND");
return (Node *) makeBoolExpr(AND_EXPR,
list_make2(lexpr, rexpr));
}
static Node *
transformAExprOr(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExpr(pstate, a->lexpr);
Node *rexpr = transformExpr(pstate, a->rexpr);
lexpr = coerce_to_boolean(pstate, lexpr, "OR");
rexpr = coerce_to_boolean(pstate, rexpr, "OR");
return (Node *) makeBoolExpr(OR_EXPR,
list_make2(lexpr, rexpr));
}
static Node *
transformAExprNot(ParseState *pstate, A_Expr *a)
{
Node *rexpr = transformExpr(pstate, a->rexpr);
rexpr = coerce_to_boolean(pstate, rexpr, "NOT");
return (Node *) makeBoolExpr(NOT_EXPR,
list_make1(rexpr));
}
static Node *
transformAExprOpAny(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExpr(pstate, a->lexpr);
Node *rexpr = transformExpr(pstate, a->rexpr);
return (Node *) make_scalar_array_op(pstate,
a->name,
true,
lexpr,
rexpr,
a->location);
}
static Node *
transformAExprOpAll(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExpr(pstate, a->lexpr);
Node *rexpr = transformExpr(pstate, a->rexpr);
return (Node *) make_scalar_array_op(pstate,
a->name,
false,
lexpr,
rexpr,
a->location);
}
static Node *
transformAExprDistinct(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExpr(pstate, a->lexpr);
Node *rexpr = transformExpr(pstate, a->rexpr);
if (lexpr && IsA(lexpr, RowExpr) &&
rexpr && IsA(rexpr, RowExpr))
{
/* "row op row" */
return make_row_distinct_op(pstate, a->name,
(RowExpr *) lexpr,
(RowExpr *) rexpr,
a->location);
}
else
{
/* Ordinary scalar operator */
return (Node *) make_distinct_op(pstate,
a->name,
lexpr,
rexpr,
a->location);
}
}
static Node *
transformAExprNullIf(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExpr(pstate, a->lexpr);
Node *rexpr = transformExpr(pstate, a->rexpr);
Node *result;
result = (Node *) make_op(pstate,
a->name,
lexpr,
rexpr,
a->location);
if (((OpExpr *) result)->opresulttype != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("NULLIF requires = operator to yield boolean"),
parser_errposition(pstate, a->location)));
/*
* We rely on NullIfExpr and OpExpr being the same struct
*/
NodeSetTag(result, T_NullIfExpr);
return result;
}
static Node *
transformAExprOf(ParseState *pstate, A_Expr *a)
{
/*
* Checking an expression for match to a list of type names. Will result
* in a boolean constant node.
*/
Node *lexpr = transformExpr(pstate, a->lexpr);
ListCell *telem;
Oid ltype,
rtype;
bool matched = false;
ltype = exprType(lexpr);
foreach(telem, (List *) a->rexpr)
{
rtype = typenameTypeId(pstate, lfirst(telem));
matched = (rtype == ltype);
if (matched)
break;
}
/*
* We have two forms: equals or not equals. Flip the sense of the result
* for not equals.
*/
if (strcmp(strVal(linitial(a->name)), "<>") == 0)
matched = (!matched);
return makeBoolConst(matched, false);
}
static Node *
transformAExprIn(ParseState *pstate, A_Expr *a)
{
Node *lexpr;
List *rexprs;
List *typeids;
bool useOr;
bool haveRowExpr;
Node *result;
ListCell *l;
/*
* If the operator is <>, combine with AND not OR.
*/
if (strcmp(strVal(linitial(a->name)), "<>") == 0)
useOr = false;
else
useOr = true;
/*
* We try to generate a ScalarArrayOpExpr from IN/NOT IN, but this is only
* possible if the inputs are all scalars (no RowExprs) and there is a
* suitable array type available. If not, we fall back to a boolean
* condition tree with multiple copies of the lefthand expression.
*
* First step: transform all the inputs, and detect whether any are
* RowExprs.
*/
lexpr = transformExpr(pstate, a->lexpr);
haveRowExpr = (lexpr && IsA(lexpr, RowExpr));
typeids = list_make1_oid(exprType(lexpr));
rexprs = NIL;
foreach(l, (List *) a->rexpr)
{
Node *rexpr = transformExpr(pstate, lfirst(l));
haveRowExpr |= (rexpr && IsA(rexpr, RowExpr));
rexprs = lappend(rexprs, rexpr);
typeids = lappend_oid(typeids, exprType(rexpr));
}
/*
* If not forced by presence of RowExpr, try to resolve a common scalar
* type for all the expressions, and see if it has an array type. (But if
* there's only one righthand expression, we may as well just fall through
* and generate a simple = comparison.)
*/
if (!haveRowExpr && list_length(rexprs) != 1)
{
Oid scalar_type;
Oid array_type;
/*
* Select a common type for the array elements. Note that since the
* LHS' type is first in the list, it will be preferred when there is
* doubt (eg, when all the RHS items are unknown literals).
*/
scalar_type = select_common_type(typeids, "IN");
/* Do we have an array type to use? */
array_type = get_array_type(scalar_type);
if (array_type != InvalidOid)
{
/*
* OK: coerce all the right-hand inputs to the common type and
* build an ArrayExpr for them.
*/
List *aexprs;
ArrayExpr *newa;
aexprs = NIL;
foreach(l, rexprs)
{
Node *rexpr = (Node *) lfirst(l);
rexpr = coerce_to_common_type(pstate, rexpr,
scalar_type,
"IN");
aexprs = lappend(aexprs, rexpr);
}
newa = makeNode(ArrayExpr);
newa->array_typeid = array_type;
newa->element_typeid = scalar_type;
newa->elements = aexprs;
newa->multidims = false;
return (Node *) make_scalar_array_op(pstate,
a->name,
useOr,
lexpr,
(Node *) newa,
a->location);
}
}
/*
* Must do it the hard way, ie, with a boolean expression tree.
*/
result = NULL;
foreach(l, rexprs)
{
Node *rexpr = (Node *) lfirst(l);
Node *cmp;
if (haveRowExpr)
{
if (!IsA(lexpr, RowExpr) ||
!IsA(rexpr, RowExpr))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("arguments of row IN must all be row expressions"),
parser_errposition(pstate, a->location)));
cmp = make_row_comparison_op(pstate,
a->name,
(List *) copyObject(((RowExpr *) lexpr)->args),
((RowExpr *) rexpr)->args,
a->location);
}
else
cmp = (Node *) make_op(pstate,
a->name,
copyObject(lexpr),
rexpr,
a->location);
cmp = coerce_to_boolean(pstate, cmp, "IN");
if (result == NULL)
result = cmp;
else
result = (Node *) makeBoolExpr(useOr ? OR_EXPR : AND_EXPR,
list_make2(result, cmp));
}
return result;
}
static Node *
transformFuncCall(ParseState *pstate, FuncCall *fn)
{
List *targs;
ListCell *args;
/*
* Transform the list of arguments. We use a shallow list copy and then
* transform-in-place to avoid O(N^2) behavior from repeated lappend's.
*
* XXX: repeated lappend() would no longer result in O(n^2) behavior;
* worth reconsidering this design?
*/
targs = list_copy(fn->args);
foreach(args, targs)
{
lfirst(args) = transformExpr(pstate,
(Node *) lfirst(args));
}
return ParseFuncOrColumn(pstate,
fn->funcname,
targs,
fn->agg_star,
fn->agg_distinct,
false,
fn->location);
}
static Node *
transformCaseExpr(ParseState *pstate, CaseExpr *c)
{
CaseExpr *newc;
Node *arg;
CaseTestExpr *placeholder;
List *newargs;
List *typeids;
ListCell *l;
Node *defresult;
Oid ptype;
/* If we already transformed this node, do nothing */
if (OidIsValid(c->casetype))
return (Node *) c;
newc = makeNode(CaseExpr);
/* transform the test expression, if any */
arg = transformExpr(pstate, (Node *) c->arg);
/* generate placeholder for test expression */
if (arg)
{
/*
* If test expression is an untyped literal, force it to text. We have
* to do something now because we won't be able to do this coercion on
* the placeholder. This is not as flexible as what was done in 7.4
* and before, but it's good enough to handle the sort of silly coding
* commonly seen.
*/
if (exprType(arg) == UNKNOWNOID)
arg = coerce_to_common_type(pstate, arg, TEXTOID, "CASE");
placeholder = makeNode(CaseTestExpr);
placeholder->typeId = exprType(arg);
placeholder->typeMod = exprTypmod(arg);
}
else
placeholder = NULL;
newc->arg = (Expr *) arg;
/* transform the list of arguments */
newargs = NIL;
typeids = NIL;
foreach(l, c->args)
{
CaseWhen *w = (CaseWhen *) lfirst(l);
CaseWhen *neww = makeNode(CaseWhen);
Node *warg;
Assert(IsA(w, CaseWhen));
warg = (Node *) w->expr;
if (placeholder)
{
/* shorthand form was specified, so expand... */
warg = (Node *) makeSimpleA_Expr(AEXPR_OP, "=",
(Node *) placeholder,
warg,
-1);
}
neww->expr = (Expr *) transformExpr(pstate, warg);
neww->expr = (Expr *) coerce_to_boolean(pstate,
(Node *) neww->expr,
"CASE/WHEN");
warg = (Node *) w->result;
neww->result = (Expr *) transformExpr(pstate, warg);
newargs = lappend(newargs, neww);
typeids = lappend_oid(typeids, exprType((Node *) neww->result));
}
newc->args = newargs;
/* transform the default clause */
defresult = (Node *) c->defresult;
if (defresult == NULL)
{
A_Const *n = makeNode(A_Const);
n->val.type = T_Null;
defresult = (Node *) n;
}
newc->defresult = (Expr *) transformExpr(pstate, defresult);
/*
* Note: default result is considered the most significant type in
* determining preferred type. This is how the code worked before, but it
* seems a little bogus to me --- tgl
*/
typeids = lcons_oid(exprType((Node *) newc->defresult), typeids);
ptype = select_common_type(typeids, "CASE");
Assert(OidIsValid(ptype));
newc->casetype = ptype;
/* Convert default result clause, if necessary */
newc->defresult = (Expr *)
coerce_to_common_type(pstate,
(Node *) newc->defresult,
ptype,
"CASE/ELSE");
/* Convert when-clause results, if necessary */
foreach(l, newc->args)
{
CaseWhen *w = (CaseWhen *) lfirst(l);
w->result = (Expr *)
coerce_to_common_type(pstate,
(Node *) w->result,
ptype,
"CASE/WHEN");
}
return (Node *) newc;
}
static Node *
transformSubLink(ParseState *pstate, SubLink *sublink)
{
List *qtrees;
Query *qtree;
Node *result = (Node *) sublink;
/* If we already transformed this node, do nothing */
if (IsA(sublink->subselect, Query))
return result;
pstate->p_hasSubLinks = true;
qtrees = parse_sub_analyze(sublink->subselect, pstate);
if (list_length(qtrees) != 1)
elog(ERROR, "bad query in sub-select");
qtree = (Query *) linitial(qtrees);
if (qtree->commandType != CMD_SELECT ||
qtree->utilityStmt != NULL ||
qtree->intoClause != NULL)
elog(ERROR, "bad query in sub-select");
sublink->subselect = (Node *) qtree;
if (sublink->subLinkType == EXISTS_SUBLINK)
{
/*
* EXISTS needs no test expression or combining operator. These fields
* should be null already, but make sure.
*/
sublink->testexpr = NULL;
sublink->operName = NIL;
}
else if (sublink->subLinkType == EXPR_SUBLINK ||
sublink->subLinkType == ARRAY_SUBLINK)
{
ListCell *tlist_item = list_head(qtree->targetList);
/*
* Make sure the subselect delivers a single column (ignoring resjunk
* targets).
*/
if (tlist_item == NULL ||
((TargetEntry *) lfirst(tlist_item))->resjunk)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery must return a column")));
while ((tlist_item = lnext(tlist_item)) != NULL)
{
if (!((TargetEntry *) lfirst(tlist_item))->resjunk)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery must return only one column")));
}
/*
* EXPR and ARRAY need no test expression or combining operator. These
* fields should be null already, but make sure.
*/
sublink->testexpr = NULL;
sublink->operName = NIL;
}
else
{
/* ALL, ANY, or ROWCOMPARE: generate row-comparing expression */
Node *lefthand;
List *left_list;
List *right_list;
ListCell *l;
/*
* Transform lefthand expression, and convert to a list
*/
lefthand = transformExpr(pstate, sublink->testexpr);
if (lefthand && IsA(lefthand, RowExpr))
left_list = ((RowExpr *) lefthand)->args;
else
left_list = list_make1(lefthand);
/*
* Build a list of PARAM_SUBLINK nodes representing the output columns
* of the subquery.
*/
right_list = NIL;
foreach(l, qtree->targetList)
{
TargetEntry *tent = (TargetEntry *) lfirst(l);
Param *param;
if (tent->resjunk)
continue;
param = makeNode(Param);
param->paramkind = PARAM_SUBLINK;
param->paramid = tent->resno;
param->paramtype = exprType((Node *) tent->expr);
param->paramtypmod = exprTypmod((Node *) tent->expr);
right_list = lappend(right_list, param);
}
/*
* We could rely on make_row_comparison_op to complain if the list
* lengths differ, but we prefer to generate a more specific error
* message.
*/
if (list_length(left_list) < list_length(right_list))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery has too many columns")));
if (list_length(left_list) > list_length(right_list))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery has too few columns")));
/*
* Identify the combining operator(s) and generate a suitable
* row-comparison expression.
*/
sublink->testexpr = make_row_comparison_op(pstate,
sublink->operName,
left_list,
right_list,
-1);
}
return result;
}
static Node *
transformArrayExpr(ParseState *pstate, ArrayExpr *a)
{
ArrayExpr *newa = makeNode(ArrayExpr);
List *newelems = NIL;
List *newcoercedelems = NIL;
List *typeids = NIL;
ListCell *element;
Oid array_type;
Oid element_type;
/* Transform the element expressions */
foreach(element, a->elements)
{
Node *e = (Node *) lfirst(element);
Node *newe;
newe = transformExpr(pstate, e);
newelems = lappend(newelems, newe);
typeids = lappend_oid(typeids, exprType(newe));
}
/* Select a common type for the elements */
element_type = select_common_type(typeids, "ARRAY");
/* Coerce arguments to common type if necessary */
foreach(element, newelems)
{
Node *e = (Node *) lfirst(element);
Node *newe;
newe = coerce_to_common_type(pstate, e,
element_type,
"ARRAY");
newcoercedelems = lappend(newcoercedelems, newe);
}
/* Do we have an array type to use? */
array_type = get_array_type(element_type);
if (array_type != InvalidOid)
{
/* Elements are presumably of scalar type */
newa->multidims = false;
}
else
{
/* Must be nested array expressions */
newa->multidims = true;
array_type = element_type;
element_type = get_element_type(array_type);
if (!OidIsValid(element_type))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("could not find array type for data type %s",
format_type_be(array_type))));
}
newa->array_typeid = array_type;
newa->element_typeid = element_type;
newa->elements = newcoercedelems;
return (Node *) newa;
}
static Node *
transformRowExpr(ParseState *pstate, RowExpr *r)
{
RowExpr *newr = makeNode(RowExpr);
/* Transform the field expressions */
newr->args = transformExpressionList(pstate, r->args);
/* Barring later casting, we consider the type RECORD */
newr->row_typeid = RECORDOID;
newr->row_format = COERCE_IMPLICIT_CAST;
return (Node *) newr;
}
static Node *
transformCoalesceExpr(ParseState *pstate, CoalesceExpr *c)
{
CoalesceExpr *newc = makeNode(CoalesceExpr);
List *newargs = NIL;
List *newcoercedargs = NIL;
List *typeids = NIL;
ListCell *args;
foreach(args, c->args)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = transformExpr(pstate, e);
newargs = lappend(newargs, newe);
typeids = lappend_oid(typeids, exprType(newe));
}
newc->coalescetype = select_common_type(typeids, "COALESCE");
/* Convert arguments if necessary */
foreach(args, newargs)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = coerce_to_common_type(pstate, e,
newc->coalescetype,
"COALESCE");
newcoercedargs = lappend(newcoercedargs, newe);
}
newc->args = newcoercedargs;
return (Node *) newc;
}
static Node *
transformMinMaxExpr(ParseState *pstate, MinMaxExpr *m)
{
MinMaxExpr *newm = makeNode(MinMaxExpr);
List *newargs = NIL;
List *newcoercedargs = NIL;
List *typeids = NIL;
ListCell *args;
newm->op = m->op;
foreach(args, m->args)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = transformExpr(pstate, e);
newargs = lappend(newargs, newe);
typeids = lappend_oid(typeids, exprType(newe));
}
newm->minmaxtype = select_common_type(typeids, "GREATEST/LEAST");
/* Convert arguments if necessary */
foreach(args, newargs)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = coerce_to_common_type(pstate, e,
newm->minmaxtype,
"GREATEST/LEAST");
newcoercedargs = lappend(newcoercedargs, newe);
}
newm->args = newcoercedargs;
return (Node *) newm;
}
static Node *
transformXmlExpr(ParseState *pstate, XmlExpr *x)
{
XmlExpr *newx = makeNode(XmlExpr);
ListCell *lc;
int i;
newx->op = x->op;
if (x->name)
newx->name = map_sql_identifier_to_xml_name(x->name, false, false);
else
newx->name = NULL;
/*
* gram.y built the named args as a list of ResTarget. Transform each,
* and break the names out as a separate list.
*/
newx->named_args = NIL;
newx->arg_names = NIL;
foreach(lc, x->named_args)
{
ResTarget *r = (ResTarget *) lfirst(lc);
Node *expr;
char *argname;
Assert(IsA(r, ResTarget));
expr = transformExpr(pstate, r->val);
if (r->name)
argname = map_sql_identifier_to_xml_name(r->name, false, false);
else if (IsA(r->val, ColumnRef))
argname = map_sql_identifier_to_xml_name(FigureColname(r->val),
true, false);
else
{
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
x->op == IS_XMLELEMENT
? errmsg("unnamed XML attribute value must be a column reference")
: errmsg("unnamed XML element value must be a column reference")));
argname = NULL; /* keep compiler quiet */
}
newx->named_args = lappend(newx->named_args, expr);
newx->arg_names = lappend(newx->arg_names, makeString(argname));
}
newx->xmloption = x->xmloption;
if (x->op == IS_XMLELEMENT)
{
foreach(lc, newx->arg_names)
{
ListCell *lc2;
for_each_cell(lc2, lnext(lc))
{
if (strcmp(strVal(lfirst(lc)), strVal(lfirst(lc2))) == 0)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("XML attribute name \"%s\" appears more than once", strVal(lfirst(lc)))));
}
}
}
/* The other arguments are of varying types depending on the function */
newx->args = NIL;
i = 0;
foreach(lc, x->args)
{
Node *e = (Node *) lfirst(lc);
Node *newe;
newe = transformExpr(pstate, e);
switch (x->op)
{
case IS_XMLCONCAT:
newe = coerce_to_specific_type(pstate, newe, XMLOID,
"XMLCONCAT");
break;
case IS_XMLELEMENT:
/* no coercion necessary */
break;
case IS_XMLFOREST:
newe = coerce_to_specific_type(pstate, newe, XMLOID,
"XMLFOREST");
break;
case IS_XMLPARSE:
if (i == 0)
newe = coerce_to_specific_type(pstate, newe, TEXTOID,
"XMLPARSE");
else
newe = coerce_to_boolean(pstate, newe, "XMLPARSE");
break;
case IS_XMLPI:
newe = coerce_to_specific_type(pstate, newe, TEXTOID,
"XMLPI");
break;
case IS_XMLROOT:
if (i == 0)
newe = coerce_to_specific_type(pstate, newe, XMLOID,
"XMLROOT");
else if (i == 1)
newe = coerce_to_specific_type(pstate, newe, TEXTOID,
"XMLROOT");
else
newe = coerce_to_specific_type(pstate, newe, INT4OID,
"XMLROOT");
break;
case IS_XMLSERIALIZE:
/* not handled here */
break;
case IS_DOCUMENT:
newe = coerce_to_specific_type(pstate, newe, XMLOID,
"IS DOCUMENT");
break;
}
newx->args = lappend(newx->args, newe);
i++;
}
return (Node *) newx;
}
static Node *
transformXmlSerialize(ParseState *pstate, XmlSerialize *xs)
{
Oid targetType;
int32 targetTypmod;
XmlExpr *xexpr;
xexpr = makeNode(XmlExpr);
xexpr->op = IS_XMLSERIALIZE;
xexpr->args = list_make1(coerce_to_specific_type(pstate,
transformExpr(pstate, xs->expr),
XMLOID,
"XMLSERIALIZE"));
targetType = typenameTypeId(pstate, xs->typename);
targetTypmod = typenameTypeMod(pstate, xs->typename, targetType);
xexpr->xmloption = xs->xmloption;
/* We actually only need these to be able to parse back the expression. */
xexpr->type = targetType;
xexpr->typmod = targetTypmod;
/*
* The actual target type is determined this way. SQL allows char
* and varchar as target types. We allow anything that can be
* cast implicitly from text. This way, user-defined text-like
* data types automatically fit in.
*/
return (Node *) coerce_to_target_type(pstate, (Node *) xexpr, TEXTOID, targetType, targetTypmod,
COERCION_IMPLICIT, COERCE_IMPLICIT_CAST);
}
static Node *
transformBooleanTest(ParseState *pstate, BooleanTest *b)
{
const char *clausename;
switch (b->booltesttype)
{
case IS_TRUE:
clausename = "IS TRUE";
break;
case IS_NOT_TRUE:
clausename = "IS NOT TRUE";
break;
case IS_FALSE:
clausename = "IS FALSE";
break;
case IS_NOT_FALSE:
clausename = "IS NOT FALSE";
break;
case IS_UNKNOWN:
clausename = "IS UNKNOWN";
break;
case IS_NOT_UNKNOWN:
clausename = "IS NOT UNKNOWN";
break;
default:
elog(ERROR, "unrecognized booltesttype: %d",
(int) b->booltesttype);
clausename = NULL; /* keep compiler quiet */
}
b->arg = (Expr *) transformExpr(pstate, (Node *) b->arg);
b->arg = (Expr *) coerce_to_boolean(pstate,
(Node *) b->arg,
clausename);
return (Node *) b;
}
static Node *
transformCurrentOfExpr(ParseState *pstate, CurrentOfExpr *cexpr)
{
int sublevels_up;
/* CURRENT OF can only appear at top level of UPDATE/DELETE */
Assert(pstate->p_target_rangetblentry != NULL);
cexpr->cvarno = RTERangeTablePosn(pstate,
pstate->p_target_rangetblentry,
&sublevels_up);
Assert(sublevels_up == 0);
/* If a parameter is used, it must be of type REFCURSOR */
if (cexpr->cursor_name == NULL)
{
Oid *pptype = find_param_type(pstate, cexpr->cursor_param);
if (pstate->p_variableparams && *pptype == UNKNOWNOID)
{
/* resolve unknown param type as REFCURSOR */
*pptype = REFCURSOROID;
}
else if (*pptype != REFCURSOROID)
{
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_PARAMETER),
errmsg("inconsistent types deduced for parameter $%d",
cexpr->cursor_param),
errdetail("%s versus %s",
format_type_be(*pptype),
format_type_be(REFCURSOROID))));
}
}
return (Node *) cexpr;
}
/*
* Construct a whole-row reference to represent the notation "relation.*".
*
* A whole-row reference is a Var with varno set to the correct range
* table entry, and varattno == 0 to signal that it references the whole
* tuple. (Use of zero here is unclean, since it could easily be confused
* with error cases, but it's not worth changing now.) The vartype indicates
* a rowtype; either a named composite type, or RECORD.
*/
static Node *
transformWholeRowRef(ParseState *pstate, char *schemaname, char *relname,
int location)
{
Node *result;
RangeTblEntry *rte;
int vnum;
int sublevels_up;
Oid toid;
/* Look up the referenced RTE, creating it if needed */
rte = refnameRangeTblEntry(pstate, schemaname, relname,
&sublevels_up);
if (rte == NULL)
rte = addImplicitRTE(pstate, makeRangeVar(schemaname, relname),
location);
vnum = RTERangeTablePosn(pstate, rte, &sublevels_up);
/* Build the appropriate referencing node */
switch (rte->rtekind)
{
case RTE_RELATION:
/* relation: the rowtype is a named composite type */
toid = get_rel_type_id(rte->relid);
if (!OidIsValid(toid))
elog(ERROR, "could not find type OID for relation %u",
rte->relid);
result = (Node *) makeVar(vnum,
InvalidAttrNumber,
toid,
-1,
sublevels_up);
break;
case RTE_FUNCTION:
toid = exprType(rte->funcexpr);
if (type_is_rowtype(toid))
{
/* func returns composite; same as relation case */
result = (Node *) makeVar(vnum,
InvalidAttrNumber,
toid,
-1,
sublevels_up);
}
else
{
/*
* func returns scalar; instead of making a whole-row Var,
* just reference the function's scalar output. (XXX this
* seems a tad inconsistent, especially if "f.*" was
* explicitly written ...)
*/
result = (Node *) makeVar(vnum,
1,
toid,
-1,
sublevels_up);
}
break;
case RTE_VALUES:
toid = RECORDOID;
/* returns composite; same as relation case */
result = (Node *) makeVar(vnum,
InvalidAttrNumber,
toid,
-1,
sublevels_up);
break;
default:
/*
* RTE is a join or subselect. We represent this as a whole-row
* Var of RECORD type. (Note that in most cases the Var will be
* expanded to a RowExpr during planning, but that is not our
* concern here.)
*/
result = (Node *) makeVar(vnum,
InvalidAttrNumber,
RECORDOID,
-1,
sublevels_up);
break;
}
return result;
}
/*
* exprType -
* returns the Oid of the type of the expression. (Used for typechecking.)
*/
Oid
exprType(Node *expr)
{
Oid type;
if (!expr)
return InvalidOid;
switch (nodeTag(expr))
{
case T_Var:
type = ((Var *) expr)->vartype;
break;
case T_Const:
type = ((Const *) expr)->consttype;
break;
case T_Param:
type = ((Param *) expr)->paramtype;
break;
case T_Aggref:
type = ((Aggref *) expr)->aggtype;
break;
case T_ArrayRef:
{
ArrayRef *arrayref = (ArrayRef *) expr;
/* slice and/or store operations yield the array type */
if (arrayref->reflowerindexpr || arrayref->refassgnexpr)
type = arrayref->refarraytype;
else
type = arrayref->refelemtype;
}
break;
case T_FuncExpr:
type = ((FuncExpr *) expr)->funcresulttype;
break;
case T_OpExpr:
type = ((OpExpr *) expr)->opresulttype;
break;
case T_DistinctExpr:
type = ((DistinctExpr *) expr)->opresulttype;
break;
case T_ScalarArrayOpExpr:
type = BOOLOID;
break;
case T_BoolExpr:
type = BOOLOID;
break;
case T_SubLink:
{
SubLink *sublink = (SubLink *) expr;
if (sublink->subLinkType == EXPR_SUBLINK ||
sublink->subLinkType == ARRAY_SUBLINK)
{
/* get the type of the subselect's first target column */
Query *qtree = (Query *) sublink->subselect;
TargetEntry *tent;
if (!qtree || !IsA(qtree, Query))
elog(ERROR, "cannot get type for untransformed sublink");
tent = (TargetEntry *) linitial(qtree->targetList);
Assert(IsA(tent, TargetEntry));
Assert(!tent->resjunk);
type = exprType((Node *) tent->expr);
if (sublink->subLinkType == ARRAY_SUBLINK)
{
type = get_array_type(type);
if (!OidIsValid(type))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("could not find array type for data type %s",
format_type_be(exprType((Node *) tent->expr)))));
}
}
else
{
/* for all other sublink types, result is boolean */
type = BOOLOID;
}
}
break;
case T_SubPlan:
{
/*
* Although the parser does not ever deal with already-planned
* expression trees, we support SubPlan nodes in this routine
* for the convenience of ruleutils.c.
*/
SubPlan *subplan = (SubPlan *) expr;
if (subplan->subLinkType == EXPR_SUBLINK ||
subplan->subLinkType == ARRAY_SUBLINK)
{
/* get the type of the subselect's first target column */
type = subplan->firstColType;
if (subplan->subLinkType == ARRAY_SUBLINK)
{
type = get_array_type(type);
if (!OidIsValid(type))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("could not find array type for data type %s",
format_type_be(subplan->firstColType))));
}
}
else
{
/* for all other subplan types, result is boolean */
type = BOOLOID;
}
}
break;
case T_FieldSelect:
type = ((FieldSelect *) expr)->resulttype;
break;
case T_FieldStore:
type = ((FieldStore *) expr)->resulttype;
break;
case T_RelabelType:
type = ((RelabelType *) expr)->resulttype;
break;
case T_CoerceViaIO:
type = ((CoerceViaIO *) expr)->resulttype;
break;
case T_ArrayCoerceExpr:
type = ((ArrayCoerceExpr *) expr)->resulttype;
break;
case T_ConvertRowtypeExpr:
type = ((ConvertRowtypeExpr *) expr)->resulttype;
break;
case T_CaseExpr:
type = ((CaseExpr *) expr)->casetype;
break;
case T_CaseTestExpr:
type = ((CaseTestExpr *) expr)->typeId;
break;
case T_ArrayExpr:
type = ((ArrayExpr *) expr)->array_typeid;
break;
case T_RowExpr:
type = ((RowExpr *) expr)->row_typeid;
break;
case T_RowCompareExpr:
type = BOOLOID;
break;
case T_CoalesceExpr:
type = ((CoalesceExpr *) expr)->coalescetype;
break;
case T_MinMaxExpr:
type = ((MinMaxExpr *) expr)->minmaxtype;
break;
case T_XmlExpr:
if (((XmlExpr *) expr)->op == IS_DOCUMENT)
type = BOOLOID;
else if (((XmlExpr *) expr)->op == IS_XMLSERIALIZE)
type = TEXTOID;
else
type = XMLOID;
break;
case T_NullIfExpr:
type = exprType((Node *) linitial(((NullIfExpr *) expr)->args));
break;
case T_NullTest:
type = BOOLOID;
break;
case T_BooleanTest:
type = BOOLOID;
break;
case T_CoerceToDomain:
type = ((CoerceToDomain *) expr)->resulttype;
break;
case T_CoerceToDomainValue:
type = ((CoerceToDomainValue *) expr)->typeId;
break;
case T_SetToDefault:
type = ((SetToDefault *) expr)->typeId;
break;
case T_CurrentOfExpr:
type = BOOLOID;
break;
default:
elog(ERROR, "unrecognized node type: %d", (int) nodeTag(expr));
type = InvalidOid; /* keep compiler quiet */
break;
}
return type;
}
/*
* exprTypmod -
* returns the type-specific attrmod of the expression, if it can be
* determined. In most cases, it can't and we return -1.
*/
int32
exprTypmod(Node *expr)
{
if (!expr)
return -1;
switch (nodeTag(expr))
{
case T_Var:
return ((Var *) expr)->vartypmod;
case T_Const:
return ((Const *) expr)->consttypmod;
case T_Param:
return ((Param *) expr)->paramtypmod;
case T_ArrayRef:
/* typmod is the same for array or element */
return ((ArrayRef *) expr)->reftypmod;
case T_FuncExpr:
{
int32 coercedTypmod;
/* Be smart about length-coercion functions... */
if (exprIsLengthCoercion(expr, &coercedTypmod))
return coercedTypmod;
}
break;
case T_SubLink:
{
SubLink *sublink = (SubLink *) expr;
if (sublink->subLinkType == EXPR_SUBLINK ||
sublink->subLinkType == ARRAY_SUBLINK)
{
/* get the typmod of the subselect's first target column */
Query *qtree = (Query *) sublink->subselect;
TargetEntry *tent;
if (!qtree || !IsA(qtree, Query))
elog(ERROR, "cannot get type for untransformed sublink");
tent = (TargetEntry *) linitial(qtree->targetList);
Assert(IsA(tent, TargetEntry));
Assert(!tent->resjunk);
return exprTypmod((Node *) tent->expr);
/* note we don't need to care if it's an array */
}
}
break;
case T_FieldSelect:
return ((FieldSelect *) expr)->resulttypmod;
case T_RelabelType:
return ((RelabelType *) expr)->resulttypmod;
case T_ArrayCoerceExpr:
return ((ArrayCoerceExpr *) expr)->resulttypmod;
case T_CaseExpr:
{
/*
* If all the alternatives agree on type/typmod, return that
* typmod, else use -1
*/
CaseExpr *cexpr = (CaseExpr *) expr;
Oid casetype = cexpr->casetype;
int32 typmod;
ListCell *arg;
if (!cexpr->defresult)
return -1;
if (exprType((Node *) cexpr->defresult) != casetype)
return -1;
typmod = exprTypmod((Node *) cexpr->defresult);
if (typmod < 0)
return -1; /* no point in trying harder */
foreach(arg, cexpr->args)
{
CaseWhen *w = (CaseWhen *) lfirst(arg);
Assert(IsA(w, CaseWhen));
if (exprType((Node *) w->result) != casetype)
return -1;
if (exprTypmod((Node *) w->result) != typmod)
return -1;
}
return typmod;
}
break;
case T_CaseTestExpr:
return ((CaseTestExpr *) expr)->typeMod;
case T_ArrayExpr:
{
/*
* If all the elements agree on type/typmod, return that
* typmod, else use -1
*/
ArrayExpr *arrayexpr = (ArrayExpr *) expr;
Oid commontype;
int32 typmod;
ListCell *elem;
if (arrayexpr->elements == NIL)
return -1;
typmod = exprTypmod((Node *) linitial(arrayexpr->elements));
if (typmod < 0)
return -1; /* no point in trying harder */
if (arrayexpr->multidims)
commontype = arrayexpr->array_typeid;
else
commontype = arrayexpr->element_typeid;
foreach(elem, arrayexpr->elements)
{
Node *e = (Node *) lfirst(elem);
if (exprType(e) != commontype)
return -1;
if (exprTypmod(e) != typmod)
return -1;
}
return typmod;
}
break;
case T_CoalesceExpr:
{
/*
* If all the alternatives agree on type/typmod, return that
* typmod, else use -1
*/
CoalesceExpr *cexpr = (CoalesceExpr *) expr;
Oid coalescetype = cexpr->coalescetype;
int32 typmod;
ListCell *arg;
if (exprType((Node *) linitial(cexpr->args)) != coalescetype)
return -1;
typmod = exprTypmod((Node *) linitial(cexpr->args));
if (typmod < 0)
return -1; /* no point in trying harder */
for_each_cell(arg, lnext(list_head(cexpr->args)))
{
Node *e = (Node *) lfirst(arg);
if (exprType(e) != coalescetype)
return -1;
if (exprTypmod(e) != typmod)
return -1;
}
return typmod;
}
break;
case T_MinMaxExpr:
{
/*
* If all the alternatives agree on type/typmod, return that
* typmod, else use -1
*/
MinMaxExpr *mexpr = (MinMaxExpr *) expr;
Oid minmaxtype = mexpr->minmaxtype;
int32 typmod;
ListCell *arg;
if (exprType((Node *) linitial(mexpr->args)) != minmaxtype)
return -1;
typmod = exprTypmod((Node *) linitial(mexpr->args));
if (typmod < 0)
return -1; /* no point in trying harder */
for_each_cell(arg, lnext(list_head(mexpr->args)))
{
Node *e = (Node *) lfirst(arg);
if (exprType(e) != minmaxtype)
return -1;
if (exprTypmod(e) != typmod)
return -1;
}
return typmod;
}
break;
case T_NullIfExpr:
{
NullIfExpr *nexpr = (NullIfExpr *) expr;
return exprTypmod((Node *) linitial(nexpr->args));
}
break;
case T_CoerceToDomain:
return ((CoerceToDomain *) expr)->resulttypmod;
case T_CoerceToDomainValue:
return ((CoerceToDomainValue *) expr)->typeMod;
case T_SetToDefault:
return ((SetToDefault *) expr)->typeMod;
default:
break;
}
return -1;
}
/*
* exprIsLengthCoercion
* Detect whether an expression tree is an application of a datatype's
* typmod-coercion function. Optionally extract the result's typmod.
*
* If coercedTypmod is not NULL, the typmod is stored there if the expression
* is a length-coercion function, else -1 is stored there.
*
* Note that a combined type-and-length coercion will be treated as a
* length coercion by this routine.
*/
bool
exprIsLengthCoercion(Node *expr, int32 *coercedTypmod)
{
if (coercedTypmod != NULL)
*coercedTypmod = -1; /* default result on failure */
/*
* Scalar-type length coercions are FuncExprs, array-type length
* coercions are ArrayCoerceExprs
*/
if (expr && IsA(expr, FuncExpr))
{
FuncExpr *func = (FuncExpr *) expr;
int nargs;
Const *second_arg;
/*
* If it didn't come from a coercion context, reject.
*/
if (func->funcformat != COERCE_EXPLICIT_CAST &&
func->funcformat != COERCE_IMPLICIT_CAST)
return false;
/*
* If it's not a two-argument or three-argument function with the
* second argument being an int4 constant, it can't have been created
* from a length coercion (it must be a type coercion, instead).
*/
nargs = list_length(func->args);
if (nargs < 2 || nargs > 3)
return false;
second_arg = (Const *) lsecond(func->args);
if (!IsA(second_arg, Const) ||
second_arg->consttype != INT4OID ||
second_arg->constisnull)
return false;
/*
* OK, it is indeed a length-coercion function.
*/
if (coercedTypmod != NULL)
*coercedTypmod = DatumGetInt32(second_arg->constvalue);
return true;
}
if (expr && IsA(expr, ArrayCoerceExpr))
{
ArrayCoerceExpr *acoerce = (ArrayCoerceExpr *) expr;
/* It's not a length coercion unless there's a nondefault typmod */
if (acoerce->resulttypmod < 0)
return false;
/*
* OK, it is indeed a length-coercion expression.
*/
if (coercedTypmod != NULL)
*coercedTypmod = acoerce->resulttypmod;
return true;
}
return false;
}
/*
* Handle an explicit CAST construct.
*
* The given expr has already been transformed, but we need to lookup
* the type name and then apply any necessary coercion function(s).
*/
static Node *
typecast_expression(ParseState *pstate, Node *expr, TypeName *typename)
{
Oid inputType = exprType(expr);
Oid targetType;
int32 targetTypmod;
targetType = typenameTypeId(pstate, typename);
targetTypmod = typenameTypeMod(pstate, typename, targetType);
if (inputType == InvalidOid)
return expr; /* do nothing if NULL input */
expr = coerce_to_target_type(pstate, expr, inputType,
targetType, targetTypmod,
COERCION_EXPLICIT,
COERCE_EXPLICIT_CAST);
if (expr == NULL)
ereport(ERROR,
(errcode(ERRCODE_CANNOT_COERCE),
errmsg("cannot cast type %s to %s",
format_type_be(inputType),
format_type_be(targetType)),
parser_errposition(pstate, typename->location)));
return expr;
}
/*
* Transform a "row compare-op row" construct
*
* The inputs are lists of already-transformed expressions.
* As with coerce_type, pstate may be NULL if no special unknown-Param
* processing is wanted.
*
* The output may be a single OpExpr, an AND or OR combination of OpExprs,
* or a RowCompareExpr. In all cases it is guaranteed to return boolean.
* The AND, OR, and RowCompareExpr cases further imply things about the
* behavior of the operators (ie, they behave as =, <>, or < <= > >=).
*/
static Node *
make_row_comparison_op(ParseState *pstate, List *opname,
List *largs, List *rargs, int location)
{
RowCompareExpr *rcexpr;
RowCompareType rctype;
List *opexprs;
List *opnos;
List *opfamilies;
ListCell *l,
*r;
List **opfamily_lists;
List **opstrat_lists;
Bitmapset *strats;
int nopers;
int i;
nopers = list_length(largs);
if (nopers != list_length(rargs))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unequal number of entries in row expressions"),
parser_errposition(pstate, location)));
/*
* We can't compare zero-length rows because there is no principled basis
* for figuring out what the operator is.
*/
if (nopers == 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot compare rows of zero length"),
parser_errposition(pstate, location)));
/*
* Identify all the pairwise operators, using make_op so that behavior is
* the same as in the simple scalar case.
*/
opexprs = NIL;
forboth(l, largs, r, rargs)
{
Node *larg = (Node *) lfirst(l);
Node *rarg = (Node *) lfirst(r);
OpExpr *cmp;
cmp = (OpExpr *) make_op(pstate, opname, larg, rarg, location);
Assert(IsA(cmp, OpExpr));
/*
* We don't use coerce_to_boolean here because we insist on the
* operator yielding boolean directly, not via coercion. If it
* doesn't yield bool it won't be in any index opfamilies...
*/
if (cmp->opresulttype != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("row comparison operator must yield type boolean, "
"not type %s",
format_type_be(cmp->opresulttype)),
parser_errposition(pstate, location)));
if (expression_returns_set((Node *) cmp))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("row comparison operator must not return a set"),
parser_errposition(pstate, location)));
opexprs = lappend(opexprs, cmp);
}
/*
* If rows are length 1, just return the single operator. In this case we
* don't insist on identifying btree semantics for the operator (but we
* still require it to return boolean).
*/
if (nopers == 1)
return (Node *) linitial(opexprs);
/*
* Now we must determine which row comparison semantics (= <> < <= > >=)
* apply to this set of operators. We look for btree opfamilies containing
* the operators, and see which interpretations (strategy numbers) exist
* for each operator.
*/
opfamily_lists = (List **) palloc(nopers * sizeof(List *));
opstrat_lists = (List **) palloc(nopers * sizeof(List *));
strats = NULL;
i = 0;
foreach(l, opexprs)
{
Oid opno = ((OpExpr *) lfirst(l))->opno;
Bitmapset *this_strats;
ListCell *j;
get_op_btree_interpretation(opno,
&opfamily_lists[i], &opstrat_lists[i]);
/*
* convert strategy number list to a Bitmapset to make the
* intersection calculation easy.
*/
this_strats = NULL;
foreach(j, opstrat_lists[i])
{
this_strats = bms_add_member(this_strats, lfirst_int(j));
}
if (i == 0)
strats = this_strats;
else
strats = bms_int_members(strats, this_strats);
i++;
}
/*
* If there are multiple common interpretations, we may use any one of
* them ... this coding arbitrarily picks the lowest btree strategy
* number.
*/
i = bms_first_member(strats);
if (i < 0)
{
/* No common interpretation, so fail */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not determine interpretation of row comparison operator %s",
strVal(llast(opname))),
errhint("Row comparison operators must be associated with btree operator families."),
parser_errposition(pstate, location)));
}
rctype = (RowCompareType) i;
/*
* For = and <> cases, we just combine the pairwise operators with AND or
* OR respectively.
*
* Note: this is presently the only place where the parser generates
* BoolExpr with more than two arguments. Should be OK since the rest of
* the system thinks BoolExpr is N-argument anyway.
*/
if (rctype == ROWCOMPARE_EQ)
return (Node *) makeBoolExpr(AND_EXPR, opexprs);
if (rctype == ROWCOMPARE_NE)
return (Node *) makeBoolExpr(OR_EXPR, opexprs);
/*
* Otherwise we need to choose exactly which opfamily to associate with
* each operator.
*/
opfamilies = NIL;
for (i = 0; i < nopers; i++)
{
Oid opfamily = InvalidOid;
forboth(l, opfamily_lists[i], r, opstrat_lists[i])
{
int opstrat = lfirst_int(r);
if (opstrat == rctype)
{
opfamily = lfirst_oid(l);
break;
}
}
if (OidIsValid(opfamily))
opfamilies = lappend_oid(opfamilies, opfamily);
else /* should not happen */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not determine interpretation of row comparison operator %s",
strVal(llast(opname))),
errdetail("There are multiple equally-plausible candidates."),
parser_errposition(pstate, location)));
}
/*
* Now deconstruct the OpExprs and create a RowCompareExpr.
*
* Note: can't just reuse the passed largs/rargs lists, because of
* possibility that make_op inserted coercion operations.
*/
opnos = NIL;
largs = NIL;
rargs = NIL;
foreach(l, opexprs)
{
OpExpr *cmp = (OpExpr *) lfirst(l);
opnos = lappend_oid(opnos, cmp->opno);
largs = lappend(largs, linitial(cmp->args));
rargs = lappend(rargs, lsecond(cmp->args));
}
rcexpr = makeNode(RowCompareExpr);
rcexpr->rctype = rctype;
rcexpr->opnos = opnos;
rcexpr->opfamilies = opfamilies;
rcexpr->largs = largs;
rcexpr->rargs = rargs;
return (Node *) rcexpr;
}
/*
* Transform a "row IS DISTINCT FROM row" construct
*
* The input RowExprs are already transformed
*/
static Node *
make_row_distinct_op(ParseState *pstate, List *opname,
RowExpr *lrow, RowExpr *rrow,
int location)
{
Node *result = NULL;
List *largs = lrow->args;
List *rargs = rrow->args;
ListCell *l,
*r;
if (list_length(largs) != list_length(rargs))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unequal number of entries in row expressions"),
parser_errposition(pstate, location)));
forboth(l, largs, r, rargs)
{
Node *larg = (Node *) lfirst(l);
Node *rarg = (Node *) lfirst(r);
Node *cmp;
cmp = (Node *) make_distinct_op(pstate, opname, larg, rarg, location);
if (result == NULL)
result = cmp;
else
result = (Node *) makeBoolExpr(OR_EXPR,
list_make2(result, cmp));
}
if (result == NULL)
{
/* zero-length rows? Generate constant FALSE */
result = makeBoolConst(false, false);
}
return result;
}
/*
* make the node for an IS DISTINCT FROM operator
*/
static Expr *
make_distinct_op(ParseState *pstate, List *opname, Node *ltree, Node *rtree,
int location)
{
Expr *result;
result = make_op(pstate, opname, ltree, rtree, location);
if (((OpExpr *) result)->opresulttype != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("IS DISTINCT FROM requires = operator to yield boolean"),
parser_errposition(pstate, location)));
/*
* We rely on DistinctExpr and OpExpr being same struct
*/
NodeSetTag(result, T_DistinctExpr);
return result;
}
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