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postgres/src/backend/parser/parse_expr.c
Bruce Momjian 927d61eeff Run pgindent on 9.2 source tree in preparation for first 9.3 
commit-fest.
2012-06-10 15:20:04 -04:00

2448 lines
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/*-------------------------------------------------------------------------
*
* parse_expr.c
* handle expressions in parser
*
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/parser/parse_expr.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/pg_type.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/var.h"
#include "parser/analyze.h"
#include "parser/parse_coerce.h"
#include "parser/parse_collate.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, A_ArrayExpr *a,
Oid array_type, Oid element_type, int32 typmod);
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, RangeTblEntry *rte,
int location);
static Node *transformIndirection(ParseState *pstate, Node *basenode,
List *indirection);
static Node *transformTypeCast(ParseState *pstate, TypeCast *tc);
static Node *transformCollateClause(ParseState *pstate, CollateClause *c);
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(pstate, val, con->location);
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_A_ArrayExpr:
result = transformArrayExpr(pstate, (A_ArrayExpr *) expr,
InvalidOid, InvalidOid, -1);
break;
case T_TypeCast:
{
TypeCast *tc = (TypeCast *) expr;
/*
* If the subject of the typecast is an ARRAY[] construct and
* the target type is an array type, we invoke
* transformArrayExpr() directly so that we can pass down the
* type information. This avoids some cases where
* transformArrayExpr() might not infer the correct type.
*/
if (IsA(tc->arg, A_ArrayExpr))
{
Oid targetType;
Oid elementType;
int32 targetTypmod;
typenameTypeIdAndMod(pstate, tc->typeName,
&targetType, &targetTypmod);
/*
* If target is a domain over array, work with the base
* array type here. transformTypeCast below will cast the
* array type to the domain. In the usual case that the
* target is not a domain, transformTypeCast is a no-op.
*/
targetType = getBaseTypeAndTypmod(targetType,
&targetTypmod);
elementType = get_element_type(targetType);
if (OidIsValid(elementType))
{
tc = copyObject(tc);
tc->arg = transformArrayExpr(pstate,
(A_ArrayExpr *) tc->arg,
targetType,
elementType,
targetTypmod);
}
}
result = transformTypeCast(pstate, tc);
break;
}
case T_CollateClause:
result = transformCollateClause(pstate, (CollateClause *) expr);
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_NamedArgExpr:
{
NamedArgExpr *na = (NamedArgExpr *) expr;
na->arg = (Expr *) transformExpr(pstate, (Node *) na->arg);
result = expr;
break;
}
case T_SubLink:
result = transformSubLink(pstate, (SubLink *) expr);
break;
case T_CaseExpr:
result = transformCaseExpr(pstate, (CaseExpr *) 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 */
n->argisrow = type_is_rowtype(exprType((Node *) n->arg));
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_WindowFunc:
case T_ArrayRef:
case T_FuncExpr:
case T_OpExpr:
case T_DistinctExpr:
case T_NullIfExpr:
case T_ScalarArrayOpExpr:
case T_BoolExpr:
case T_FieldSelect:
case T_FieldStore:
case T_RelabelType:
case T_CoerceViaIO:
case T_ArrayCoerceExpr:
case T_ConvertRowtypeExpr:
case T_CollateExpr:
case T_CaseTestExpr:
case T_ArrayExpr:
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;
}
/*
* helper routine for delivering "column does not exist" error message
*
* (Usually we don't have to work this hard, but the general case of field
* selection from an arbitrary node needs it.)
*/
static void
unknown_attribute(ParseState *pstate, Node *relref, char *attname,
int location)
{
RangeTblEntry *rte;
if (IsA(relref, Var) &&
((Var *) relref)->varattno == InvalidAttrNumber)
{
/* Reference the RTE by alias not by actual table name */
rte = GetRTEByRangeTablePosn(pstate,
((Var *) relref)->varno,
((Var *) relref)->varlevelsup);
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column %s.%s does not exist",
rte->eref->aliasname, attname),
parser_errposition(pstate, location)));
}
else
{
/* Have to do it by reference to the type of the expression */
Oid relTypeId = exprType(relref);
if (ISCOMPLEX(relTypeId))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" not found in data type %s",
attname, format_type_be(relTypeId)),
parser_errposition(pstate, location)));
else if (relTypeId == RECORDOID)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("could not identify column \"%s\" in record data type",
attname),
parser_errposition(pstate, location)));
else
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("column notation .%s applied to type %s, "
"which is not a composite type",
attname, format_type_be(relTypeId)),
parser_errposition(pstate, location)));
}
}
static Node *
transformIndirection(ParseState *pstate, Node *basenode, List *indirection)
{
Node *result = basenode;
List *subscripts = NIL;
int location = exprLocation(basenode);
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 if (IsA(n, A_Star))
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("row expansion via \"*\" is not supported here"),
parser_errposition(pstate, location)));
}
else
{
Node *newresult;
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;
newresult = ParseFuncOrColumn(pstate,
list_make1(n),
list_make1(result),
NIL, false, false, false,
NULL, true, location);
if (newresult == NULL)
unknown_attribute(pstate, result, strVal(n), location);
result = newresult;
}
}
/* process trailing subscripts, if any */
if (subscripts)
result = (Node *) transformArraySubscripts(pstate,
result,
exprType(result),
InvalidOid,
exprTypmod(result),
subscripts,
NULL);
return result;
}
/*
* Transform a ColumnRef.
*
* If you find yourself changing this code, see also ExpandColumnRefStar.
*/
static Node *
transformColumnRef(ParseState *pstate, ColumnRef *cref)
{
Node *node = NULL;
char *nspname = NULL;
char *relname = NULL;
char *colname = NULL;
RangeTblEntry *rte;
int levels_up;
enum
{
CRERR_NO_COLUMN,
CRERR_NO_RTE,
CRERR_WRONG_DB,
CRERR_TOO_MANY
} crerr = CRERR_NO_COLUMN;
/*
* Give the PreParseColumnRefHook, if any, first shot. If it returns
* non-null then that's all, folks.
*/
if (pstate->p_pre_columnref_hook != NULL)
{
node = (*pstate->p_pre_columnref_hook) (pstate, cref);
if (node != NULL)
return node;
}
/*----------
* 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 (list_length(cref->fields))
{
case 1:
{
Node *field1 = (Node *) linitial(cref->fields);
Assert(IsA(field1, String));
colname = strVal(field1);
/* Try to identify as an unqualified column */
node = colNameToVar(pstate, colname, 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(colname, "value") == 0)
{
node = (Node *) copyObject(pstate->p_value_substitute);
/*
* Try to propagate location knowledge. This should
* be extended if p_value_substitute can ever take on
* other node types.
*/
if (IsA(node, CoerceToDomainValue))
((CoerceToDomainValue *) node)->location = cref->location;
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.*".
*/
rte = refnameRangeTblEntry(pstate, NULL, colname,
cref->location,
&levels_up);
if (rte)
node = transformWholeRowRef(pstate, rte,
cref->location);
}
break;
}
case 2:
{
Node *field1 = (Node *) linitial(cref->fields);
Node *field2 = (Node *) lsecond(cref->fields);
Assert(IsA(field1, String));
relname = strVal(field1);
/* Locate the referenced RTE */
rte = refnameRangeTblEntry(pstate, nspname, relname,
cref->location,
&levels_up);
if (rte == NULL)
{
crerr = CRERR_NO_RTE;
break;
}
/* Whole-row reference? */
if (IsA(field2, A_Star))
{
node = transformWholeRowRef(pstate, rte, cref->location);
break;
}
Assert(IsA(field2, String));
colname = strVal(field2);
/* Try to identify as a column of the RTE */
node = scanRTEForColumn(pstate, rte, colname, cref->location);
if (node == NULL)
{
/* Try it as a function call on the whole row */
node = transformWholeRowRef(pstate, rte, cref->location);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(colname)),
list_make1(node),
NIL, false, false, false,
NULL, true, cref->location);
}
break;
}
case 3:
{
Node *field1 = (Node *) linitial(cref->fields);
Node *field2 = (Node *) lsecond(cref->fields);
Node *field3 = (Node *) lthird(cref->fields);
Assert(IsA(field1, String));
nspname = strVal(field1);
Assert(IsA(field2, String));
relname = strVal(field2);
/* Locate the referenced RTE */
rte = refnameRangeTblEntry(pstate, nspname, relname,
cref->location,
&levels_up);
if (rte == NULL)
{
crerr = CRERR_NO_RTE;
break;
}
/* Whole-row reference? */
if (IsA(field3, A_Star))
{
node = transformWholeRowRef(pstate, rte, cref->location);
break;
}
Assert(IsA(field3, String));
colname = strVal(field3);
/* Try to identify as a column of the RTE */
node = scanRTEForColumn(pstate, rte, colname, cref->location);
if (node == NULL)
{
/* Try it as a function call on the whole row */
node = transformWholeRowRef(pstate, rte, cref->location);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(colname)),
list_make1(node),
NIL, false, false, false,
NULL, true, cref->location);
}
break;
}
case 4:
{
Node *field1 = (Node *) linitial(cref->fields);
Node *field2 = (Node *) lsecond(cref->fields);
Node *field3 = (Node *) lthird(cref->fields);
Node *field4 = (Node *) lfourth(cref->fields);
char *catname;
Assert(IsA(field1, String));
catname = strVal(field1);
Assert(IsA(field2, String));
nspname = strVal(field2);
Assert(IsA(field3, String));
relname = strVal(field3);
/*
* We check the catalog name and then ignore it.
*/
if (strcmp(catname, get_database_name(MyDatabaseId)) != 0)
{
crerr = CRERR_WRONG_DB;
break;
}
/* Locate the referenced RTE */
rte = refnameRangeTblEntry(pstate, nspname, relname,
cref->location,
&levels_up);
if (rte == NULL)
{
crerr = CRERR_NO_RTE;
break;
}
/* Whole-row reference? */
if (IsA(field4, A_Star))
{
node = transformWholeRowRef(pstate, rte, cref->location);
break;
}
Assert(IsA(field4, String));
colname = strVal(field4);
/* Try to identify as a column of the RTE */
node = scanRTEForColumn(pstate, rte, colname, cref->location);
if (node == NULL)
{
/* Try it as a function call on the whole row */
node = transformWholeRowRef(pstate, rte, cref->location);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(colname)),
list_make1(node),
NIL, false, false, false,
NULL, true, cref->location);
}
break;
}
default:
crerr = CRERR_TOO_MANY; /* too many dotted names */
break;
}
/*
* Now give the PostParseColumnRefHook, if any, a chance. We pass the
* translation-so-far so that it can throw an error if it wishes in the
* case that it has a conflicting interpretation of the ColumnRef. (If it
* just translates anyway, we'll throw an error, because we can't undo
* whatever effects the preceding steps may have had on the pstate.) If it
* returns NULL, use the standard translation, or throw a suitable error
* if there is none.
*/
if (pstate->p_post_columnref_hook != NULL)
{
Node *hookresult;
hookresult = (*pstate->p_post_columnref_hook) (pstate, cref, node);
if (node == NULL)
node = hookresult;
else if (hookresult != NULL)
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_COLUMN),
errmsg("column reference \"%s\" is ambiguous",
NameListToString(cref->fields)),
parser_errposition(pstate, cref->location)));
}
/*
* Throw error if no translation found.
*/
if (node == NULL)
{
switch (crerr)
{
case CRERR_NO_COLUMN:
if (relname)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column %s.%s does not exist",
relname, colname),
parser_errposition(pstate, cref->location)));
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" does not exist",
colname),
parser_errposition(pstate, cref->location)));
break;
case CRERR_NO_RTE:
errorMissingRTE(pstate, makeRangeVar(nspname, relname,
cref->location));
break;
case CRERR_WRONG_DB:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cross-database references are not implemented: %s",
NameListToString(cref->fields)),
parser_errposition(pstate, cref->location)));
break;
case CRERR_TOO_MANY:
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("improper qualified name (too many dotted names): %s",
NameListToString(cref->fields)),
parser_errposition(pstate, cref->location)));
break;
}
}
return node;
}
static Node *
transformParamRef(ParseState *pstate, ParamRef *pref)
{
Node *result;
/*
* The core parser knows nothing about Params. If a hook is supplied,
* call it. If not, or if the hook returns NULL, throw a generic error.
*/
if (pstate->p_paramref_hook != NULL)
result = (*pstate->p_paramref_hook) (pstate, pref);
else
result = NULL;
if (result == NULL)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_PARAMETER),
errmsg("there is no parameter $%d", pref->number),
parser_errposition(pstate, pref->location)));
return result;
}
/* Test whether an a_expr is a plain NULL constant or not */
static bool
exprIsNullConstant(Node *arg)
{
if (arg && IsA(arg, A_Const))
{
A_Const *con = (A_Const *) arg;
if (con->val.type == T_Null)
return true;
}
return false;
}
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 either side is a CaseTestExpr, then the expression was
* generated internally from a CASE-WHEN expression, and
* transform_null_equals does not apply.)
*/
if (Transform_null_equals &&
list_length(a->name) == 1 &&
strcmp(strVal(linitial(a->name)), "=") == 0 &&
(exprIsNullConstant(lexpr) || exprIsNullConstant(rexpr)) &&
(!IsA(lexpr, CaseTestExpr) &&!IsA(rexpr, CaseTestExpr)))
{
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;
s->location = a->location;
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),
a->location);
}
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),
a->location);
}
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),
a->location);
}
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);
OpExpr *result;
result = (OpExpr *) make_op(pstate,
a->name,
lexpr,
rexpr,
a->location);
/*
* The comparison operator itself should yield boolean ...
*/
if (result->opresulttype != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("NULLIF requires = operator to yield boolean"),
parser_errposition(pstate, a->location)));
/*
* ... but the NullIfExpr will yield the first operand's type.
*/
result->opresulttype = exprType((Node *) linitial(result->args));
/*
* We rely on NullIfExpr and OpExpr being the same struct
*/
NodeSetTag(result, T_NullIfExpr);
return (Node *) 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);
Const *result;
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);
result = (Const *) makeBoolConst(matched, false);
/* Make the result have the original input's parse location */
result->location = exprLocation((Node *) a);
return (Node *) result;
}
static Node *
transformAExprIn(ParseState *pstate, A_Expr *a)
{
Node *result = NULL;
Node *lexpr;
List *rexprs;
List *rvars;
List *rnonvars;
bool useOr;
bool haveRowExpr;
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. Also,
* any IN-list items that contain Vars are handled as separate boolean
* conditions, because that gives the planner more scope for optimization
* on such clauses.
*
* First step: transform all the inputs, and detect whether any are
* RowExprs or contain Vars.
*/
lexpr = transformExpr(pstate, a->lexpr);
haveRowExpr = (lexpr && IsA(lexpr, RowExpr));
rexprs = rvars = rnonvars = NIL;
foreach(l, (List *) a->rexpr)
{
Node *rexpr = transformExpr(pstate, lfirst(l));
haveRowExpr |= (rexpr && IsA(rexpr, RowExpr));
rexprs = lappend(rexprs, rexpr);
if (contain_vars_of_level(rexpr, 0))
rvars = lappend(rvars, rexpr);
else
rnonvars = lappend(rnonvars, rexpr);
}
/*
* ScalarArrayOpExpr is only going to be useful if there's more than one
* non-Var righthand item. Also, it won't work for RowExprs.
*/
if (!haveRowExpr && list_length(rnonvars) > 1)
{
List *allexprs;
Oid scalar_type;
Oid array_type;
/*
* Try to 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).
*
* Note: use list_concat here not lcons, to avoid damaging rnonvars.
*/
allexprs = list_concat(list_make1(lexpr), rnonvars);
scalar_type = select_common_type(pstate, allexprs, NULL, NULL);
/* Do we have an array type to use? */
if (OidIsValid(scalar_type))
array_type = get_array_type(scalar_type);
else
array_type = InvalidOid;
if (array_type != InvalidOid)
{
/*
* OK: coerce all the right-hand non-Var inputs to the common type
* and build an ArrayExpr for them.
*/
List *aexprs;
ArrayExpr *newa;
aexprs = NIL;
foreach(l, rnonvars)
{
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;
/* array_collid will be set by parse_collate.c */
newa->element_typeid = scalar_type;
newa->elements = aexprs;
newa->multidims = false;
newa->location = -1;
result = (Node *) make_scalar_array_op(pstate,
a->name,
useOr,
lexpr,
(Node *) newa,
a->location);
/* Consider only the Vars (if any) in the loop below */
rexprs = rvars;
}
}
/*
* Must do it the hard way, ie, with a boolean expression tree.
*/
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),
a->location);
}
return result;
}
static Node *
transformFuncCall(ParseState *pstate, FuncCall *fn)
{
List *targs;
ListCell *args;
/* Transform the list of arguments ... */
targs = NIL;
foreach(args, fn->args)
{
targs = lappend(targs, transformExpr(pstate,
(Node *) lfirst(args)));
}
/* ... and hand off to ParseFuncOrColumn */
return ParseFuncOrColumn(pstate,
fn->funcname,
targs,
fn->agg_order,
fn->agg_star,
fn->agg_distinct,
fn->func_variadic,
fn->over,
false,
fn->location);
}
static Node *
transformCaseExpr(ParseState *pstate, CaseExpr *c)
{
CaseExpr *newc;
Node *arg;
CaseTestExpr *placeholder;
List *newargs;
List *resultexprs;
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");
/*
* Run collation assignment on the test expression so that we know
* what collation to mark the placeholder with. In principle we could
* leave it to parse_collate.c to do that later, but propagating the
* result to the CaseTestExpr would be unnecessarily complicated.
*/
assign_expr_collations(pstate, arg);
placeholder = makeNode(CaseTestExpr);
placeholder->typeId = exprType(arg);
placeholder->typeMod = exprTypmod(arg);
placeholder->collation = exprCollation(arg);
}
else
placeholder = NULL;
newc->arg = (Expr *) arg;
/* transform the list of arguments */
newargs = NIL;
resultexprs = 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,
w->location);
}
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);
neww->location = w->location;
newargs = lappend(newargs, neww);
resultexprs = lappend(resultexprs, 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;
n->location = -1;
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
*/
resultexprs = lcons(newc->defresult, resultexprs);
ptype = select_common_type(pstate, resultexprs, "CASE", NULL);
Assert(OidIsValid(ptype));
newc->casetype = ptype;
/* casecollid will be set by parse_collate.c */
/* 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");
}
newc->location = c->location;
return (Node *) newc;
}
static Node *
transformSubLink(ParseState *pstate, SubLink *sublink)
{
Node *result = (Node *) sublink;
Query *qtree;
/* If we already transformed this node, do nothing */
if (IsA(sublink->subselect, Query))
return result;
pstate->p_hasSubLinks = true;
qtree = parse_sub_analyze(sublink->subselect, pstate, NULL, false);
/*
* Check that we got something reasonable. Many of these conditions are
* impossible given restrictions of the grammar, but check 'em anyway.
*/
if (!IsA(qtree, Query) ||
qtree->commandType != CMD_SELECT ||
qtree->utilityStmt != NULL)
elog(ERROR, "unexpected non-SELECT command in SubLink");
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"),
parser_errposition(pstate, sublink->location)));
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"),
parser_errposition(pstate, sublink->location)));
}
/*
* 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);
param->paramcollid = exprCollation((Node *) tent->expr);
param->location = -1;
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"),
parser_errposition(pstate, sublink->location)));
if (list_length(left_list) > list_length(right_list))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery has too few columns"),
parser_errposition(pstate, sublink->location)));
/*
* 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,
sublink->location);
}
return result;
}
/*
* transformArrayExpr
*
* If the caller specifies the target type, the resulting array will
* be of exactly that type. Otherwise we try to infer a common type
* for the elements using select_common_type().
*/
static Node *
transformArrayExpr(ParseState *pstate, A_ArrayExpr *a,
Oid array_type, Oid element_type, int32 typmod)
{
ArrayExpr *newa = makeNode(ArrayExpr);
List *newelems = NIL;
List *newcoercedelems = NIL;
ListCell *element;
Oid coerce_type;
bool coerce_hard;
/*
* Transform the element expressions
*
* Assume that the array is one-dimensional unless we find an array-type
* element expression.
*/
newa->multidims = false;
foreach(element, a->elements)
{
Node *e = (Node *) lfirst(element);
Node *newe;
/*
* If an element is itself an A_ArrayExpr, recurse directly so that we
* can pass down any target type we were given.
*/
if (IsA(e, A_ArrayExpr))
{
newe = transformArrayExpr(pstate,
(A_ArrayExpr *) e,
array_type,
element_type,
typmod);
/* we certainly have an array here */
Assert(array_type == InvalidOid || array_type == exprType(newe));
newa->multidims = true;
}
else
{
newe = transformExpr(pstate, e);
/*
* Check for sub-array expressions, if we haven't already found
* one.
*/
if (!newa->multidims && type_is_array(exprType(newe)))
newa->multidims = true;
}
newelems = lappend(newelems, newe);
}
/*
* Select a target type for the elements.
*
* If we haven't been given a target array type, we must try to deduce a
* common type based on the types of the individual elements present.
*/
if (OidIsValid(array_type))
{
/* Caller must ensure array_type matches element_type */
Assert(OidIsValid(element_type));
coerce_type = (newa->multidims ? array_type : element_type);
coerce_hard = true;
}
else
{
/* Can't handle an empty array without a target type */
if (newelems == NIL)
ereport(ERROR,
(errcode(ERRCODE_INDETERMINATE_DATATYPE),
errmsg("cannot determine type of empty array"),
errhint("Explicitly cast to the desired type, "
"for example ARRAY[]::integer[]."),
parser_errposition(pstate, a->location)));
/* Select a common type for the elements */
coerce_type = select_common_type(pstate, newelems, "ARRAY", NULL);
if (newa->multidims)
{
array_type = coerce_type;
element_type = get_element_type(array_type);
if (!OidIsValid(element_type))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("could not find element type for data type %s",
format_type_be(array_type)),
parser_errposition(pstate, a->location)));
}
else
{
element_type = coerce_type;
array_type = get_array_type(element_type);
if (!OidIsValid(array_type))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("could not find array type for data type %s",
format_type_be(element_type)),
parser_errposition(pstate, a->location)));
}
coerce_hard = false;
}
/*
* Coerce elements to target type
*
* If the array has been explicitly cast, then the elements are in turn
* explicitly coerced.
*
* If the array's type was merely derived from the common type of its
* elements, then the elements are implicitly coerced to the common type.
* This is consistent with other uses of select_common_type().
*/
foreach(element, newelems)
{
Node *e = (Node *) lfirst(element);
Node *newe;
if (coerce_hard)
{
newe = coerce_to_target_type(pstate, e,
exprType(e),
coerce_type,
typmod,
COERCION_EXPLICIT,
COERCE_EXPLICIT_CAST,
-1);
if (newe == NULL)
ereport(ERROR,
(errcode(ERRCODE_CANNOT_COERCE),
errmsg("cannot cast type %s to %s",
format_type_be(exprType(e)),
format_type_be(coerce_type)),
parser_errposition(pstate, exprLocation(e))));
}
else
newe = coerce_to_common_type(pstate, e,
coerce_type,
"ARRAY");
newcoercedelems = lappend(newcoercedelems, newe);
}
newa->array_typeid = array_type;
/* array_collid will be set by parse_collate.c */
newa->element_typeid = element_type;
newa->elements = newcoercedelems;
newa->location = a->location;
return (Node *) newa;
}
static Node *
transformRowExpr(ParseState *pstate, RowExpr *r)
{
RowExpr *newr = makeNode(RowExpr);
char fname[16];
int fnum;
ListCell *lc;
/* 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;
/* ROW() has anonymous columns, so invent some field names */
newr->colnames = NIL;
fnum = 1;
foreach(lc, newr->args)
{
snprintf(fname, sizeof(fname), "f%d", fnum++);
newr->colnames = lappend(newr->colnames, makeString(pstrdup(fname)));
}
newr->location = r->location;
return (Node *) newr;
}
static Node *
transformCoalesceExpr(ParseState *pstate, CoalesceExpr *c)
{
CoalesceExpr *newc = makeNode(CoalesceExpr);
List *newargs = NIL;
List *newcoercedargs = NIL;
ListCell *args;
foreach(args, c->args)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = transformExpr(pstate, e);
newargs = lappend(newargs, newe);
}
newc->coalescetype = select_common_type(pstate, newargs, "COALESCE", NULL);
/* coalescecollid will be set by parse_collate.c */
/* 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;
newc->location = c->location;
return (Node *) newc;
}
static Node *
transformMinMaxExpr(ParseState *pstate, MinMaxExpr *m)
{
MinMaxExpr *newm = makeNode(MinMaxExpr);
List *newargs = NIL;
List *newcoercedargs = NIL;
const char *funcname = (m->op == IS_GREATEST) ? "GREATEST" : "LEAST";
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);
}
newm->minmaxtype = select_common_type(pstate, newargs, funcname, NULL);
/* minmaxcollid and inputcollid will be set by parse_collate.c */
/* Convert arguments if necessary */
foreach(args, newargs)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = coerce_to_common_type(pstate, e,
newm->minmaxtype,
funcname);
newcoercedargs = lappend(newcoercedargs, newe);
}
newm->args = newcoercedargs;
newm->location = m->location;
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;
newx->xmloption = x->xmloption;
newx->location = x->location;
/*
* 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"),
parser_errposition(pstate, r->location)));
argname = NULL; /* keep compiler quiet */
}
/* reject duplicate argnames in XMLELEMENT only */
if (x->op == IS_XMLELEMENT)
{
ListCell *lc2;
foreach(lc2, newx->arg_names)
{
if (strcmp(argname, strVal(lfirst(lc2))) == 0)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("XML attribute name \"%s\" appears more than once",
argname),
parser_errposition(pstate, r->location)));
}
}
newx->named_args = lappend(newx->named_args, expr);
newx->arg_names = lappend(newx->arg_names, makeString(argname));
}
/* 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 */
Assert(false);
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)
{
Node *result;
XmlExpr *xexpr;
Oid targetType;
int32 targetTypmod;
xexpr = makeNode(XmlExpr);
xexpr->op = IS_XMLSERIALIZE;
xexpr->args = list_make1(coerce_to_specific_type(pstate,
transformExpr(pstate, xs->expr),
XMLOID,
"XMLSERIALIZE"));
typenameTypeIdAndMod(pstate, xs->typeName, &targetType, &targetTypmod);
xexpr->xmloption = xs->xmloption;
xexpr->location = xs->location;
/* 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.
*/
result = coerce_to_target_type(pstate, (Node *) xexpr,
TEXTOID, targetType, targetTypmod,
COERCION_IMPLICIT,
COERCE_IMPLICIT_CAST,
-1);
if (result == NULL)
ereport(ERROR,
(errcode(ERRCODE_CANNOT_COERCE),
errmsg("cannot cast XMLSERIALIZE result to %s",
format_type_be(targetType)),
parser_errposition(pstate, xexpr->location)));
return result;
}
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);
/*
* Check to see if the cursor name matches a parameter of type REFCURSOR.
* If so, replace the raw name reference with a parameter reference. (This
* is a hack for the convenience of plpgsql.)
*/
if (cexpr->cursor_name != NULL) /* in case already transformed */
{
ColumnRef *cref = makeNode(ColumnRef);
Node *node = NULL;
/* Build an unqualified ColumnRef with the given name */
cref->fields = list_make1(makeString(cexpr->cursor_name));
cref->location = -1;
/* See if there is a translation available from a parser hook */
if (pstate->p_pre_columnref_hook != NULL)
node = (*pstate->p_pre_columnref_hook) (pstate, cref);
if (node == NULL && pstate->p_post_columnref_hook != NULL)
node = (*pstate->p_post_columnref_hook) (pstate, cref, NULL);
/*
* XXX Should we throw an error if we get a translation that isn't a
* refcursor Param? For now it seems best to silently ignore false
* matches.
*/
if (node != NULL && IsA(node, Param))
{
Param *p = (Param *) node;
if (p->paramkind == PARAM_EXTERN &&
p->paramtype == REFCURSOROID)
{
/* Matches, so convert CURRENT OF to a param reference */
cexpr->cursor_name = NULL;
cexpr->cursor_param = p->paramid;
}
}
}
return (Node *) cexpr;
}
/*
* Construct a whole-row reference to represent the notation "relation.*".
*/
static Node *
transformWholeRowRef(ParseState *pstate, RangeTblEntry *rte, int location)
{
Var *result;
int vnum;
int sublevels_up;
/* Find the RTE's rangetable location */
vnum = RTERangeTablePosn(pstate, rte, &sublevels_up);
/*
* Build the appropriate referencing node. Note that if the RTE is a
* function returning scalar, we create just a plain reference to the
* function value, not a composite containing a single column. This is
* pretty inconsistent at first sight, but it's what we've done
* historically. One argument for it is that "rel" and "rel.*" mean the
* same thing for composite relations, so why not for scalar functions...
*/
result = makeWholeRowVar(rte, vnum, sublevels_up, true);
/* location is not filled in by makeWholeRowVar */
result->location = location;
/* mark relation as requiring whole-row SELECT access */
markVarForSelectPriv(pstate, result, rte);
return (Node *) result;
}
/*
* Handle an explicit CAST construct.
*
* Transform the argument, then look up the type name and apply any necessary
* coercion function(s).
*/
static Node *
transformTypeCast(ParseState *pstate, TypeCast *tc)
{
Node *result;
Node *expr = transformExpr(pstate, tc->arg);
Oid inputType = exprType(expr);
Oid targetType;
int32 targetTypmod;
int location;
typenameTypeIdAndMod(pstate, tc->typeName, &targetType, &targetTypmod);
if (inputType == InvalidOid)
return expr; /* do nothing if NULL input */
/*
* Location of the coercion is preferentially the location of the :: or
* CAST symbol, but if there is none then use the location of the type
* name (this can happen in TypeName 'string' syntax, for instance).
*/
location = tc->location;
if (location < 0)
location = tc->typeName->location;
result = coerce_to_target_type(pstate, expr, inputType,
targetType, targetTypmod,
COERCION_EXPLICIT,
COERCE_EXPLICIT_CAST,
location);
if (result == NULL)
ereport(ERROR,
(errcode(ERRCODE_CANNOT_COERCE),
errmsg("cannot cast type %s to %s",
format_type_be(inputType),
format_type_be(targetType)),
parser_coercion_errposition(pstate, location, expr)));
return result;
}
/*
* Handle an explicit COLLATE clause.
*
* Transform the argument, and look up the collation name.
*/
static Node *
transformCollateClause(ParseState *pstate, CollateClause *c)
{
CollateExpr *newc;
Oid argtype;
newc = makeNode(CollateExpr);
newc->arg = (Expr *) transformExpr(pstate, c->arg);
argtype = exprType((Node *) newc->arg);
/*
* The unknown type is not collatable, but coerce_type() takes care of it
* separately, so we'll let it go here.
*/
if (!type_is_collatable(argtype) && argtype != UNKNOWNOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("collations are not supported by type %s",
format_type_be(argtype)),
parser_errposition(pstate, c->location)));
newc->collOid = LookupCollation(pstate, c->collname, c->location);
newc->location = c->location;
return (Node *) newc;
}
/*
* 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 **opinfo_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.
*/
opinfo_lists = (List **) palloc(nopers * sizeof(List *));
strats = NULL;
i = 0;
foreach(l, opexprs)
{
Oid opno = ((OpExpr *) lfirst(l))->opno;
Bitmapset *this_strats;
ListCell *j;
opinfo_lists[i] = get_op_btree_interpretation(opno);
/*
* convert strategy numbers into a Bitmapset to make the intersection
* calculation easy.
*/
this_strats = NULL;
foreach(j, opinfo_lists[i])
{
OpBtreeInterpretation *opinfo = lfirst(j);
this_strats = bms_add_member(this_strats, opinfo->strategy);
}
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, location);
if (rctype == ROWCOMPARE_NE)
return (Node *) makeBoolExpr(OR_EXPR, opexprs, location);
/*
* Otherwise we need to choose exactly which opfamily to associate with
* each operator.
*/
opfamilies = NIL;
for (i = 0; i < nopers; i++)
{
Oid opfamily = InvalidOid;
ListCell *j;
foreach(j, opinfo_lists[i])
{
OpBtreeInterpretation *opinfo = lfirst(j);
if (opinfo->strategy == rctype)
{
opfamily = opinfo->opfamily_id;
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->inputcollids = NIL; /* assign_expr_collations will fix this */
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),
location);
}
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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