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parse_expr.c
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Tom Lane authored
recursed twice on its first argument, leading to exponential time spent on a deep nest of COALESCEs ... such as a deeply nested FULL JOIN would produce. Per report from Matt Carter.
Tom Lane authoredrecursed twice on its first argument, leading to exponential time spent on a deep nest of COALESCEs ... such as a deeply nested FULL JOIN would produce. Per report from Matt Carter.
parse_expr.c 50.35 KiB
/*-------------------------------------------------------------------------
*
* parse_expr.c
* handle expressions in parser
*
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.186 2005/11/18 23:08:00 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_proc.h"
#include "commands/dbcommands.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/params.h"
#include "nodes/plannodes.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_type.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.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 *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 *transformBooleanTest(ParseState *pstate, BooleanTest *b);
static Node *transformColumnRef(ParseState *pstate, ColumnRef *cref);
static Node *transformWholeRowRef(ParseState *pstate, char *schemaname,
char *relname);
static Node *transformBooleanTest(ParseState *pstate, BooleanTest *b);
static Node *transformIndirection(ParseState *pstate, Node *basenode,
List *indirection);
static Node *typecast_expression(ParseState *pstate, Node *expr,
TypeName *typename);
static Node *make_row_op(ParseState *pstate, List *opname,
Node *ltree, Node *rtree);
static Node *make_row_distinct_op(ParseState *pstate, List *opname,
Node *ltree, Node *rtree);
static Expr *make_distinct_op(ParseState *pstate, List *opname, Node *ltree, Node *rtree);
/*
* 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;
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_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;
/*********************************************
* 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_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,
-1,
subscripts,
NULL);
subscripts = NIL;
result = ParseFuncOrColumn(pstate,
list_make1(n),
list_make1(result),
false, false, true);
}
}
/* process trailing subscripts, if any */
if (subscripts)
result = (Node *) transformArraySubscripts(pstate,
result,
exprType(result),
InvalidOid,
-1,
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);
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);
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" does not exist",
name)));
}
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);
break;
}
/* Try to identify as a once-qualified column */
node = qualifiedNameToVar(pstate, NULL, name1, name2, true);
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);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(name2)),
list_make1(node),
false, false, true);
}
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);
break;
}
/* Try to identify as a twice-qualified column */
node = qualifiedNameToVar(pstate, name1, name2, name3, true);
if (node == NULL)
{
/* Try it as a function call */
node = transformWholeRowRef(pstate, name1, name2);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(name3)),
list_make1(node),
false, false, true);
}
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))));
/* Whole-row reference? */
if (strcmp(name4, "*") == 0)
{
node = transformWholeRowRef(pstate, name2, name3);
break;
}
/* Try to identify as a twice-qualified column */
node = qualifiedNameToVar(pstate, name2, name3, name4, true);
if (node == NULL)
{
/* Try it as a function call */
node = transformWholeRowRef(pstate, name2, name3);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(name4)),
list_make1(node),
false, false, true);
}
break;
} default:
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("improper qualified name (too many dotted names): %s",
NameListToString(cref->fields))));
node = NULL; /* keep compiler quiet */
break;
}
return node;
}
static Node *
transformParamRef(ParseState *pstate, ParamRef *pref)
{
int paramno = pref->number;
ParseState *toppstate;
Param *param;
/*
* Find topmost ParseState, which is where paramtype info lives.
*/
toppstate = pstate;
while (toppstate->parentParseState != NULL)
toppstate = toppstate->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 > toppstate->p_numparams)
{
if (!toppstate->p_variableparams)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_PARAMETER),
errmsg("there is no parameter $%d",
paramno)));
/* Okay to enlarge param array */
if (toppstate->p_paramtypes)
toppstate->p_paramtypes =
(Oid *) repalloc(toppstate->p_paramtypes,
paramno * sizeof(Oid));
else
toppstate->p_paramtypes =
(Oid *) palloc(paramno * sizeof(Oid));
/* Zero out the previously-unreferenced slots */
MemSet(toppstate->p_paramtypes + toppstate->p_numparams,
0,
(paramno - toppstate->p_numparams) * sizeof(Oid));
toppstate->p_numparams = paramno;
}
if (toppstate->p_variableparams)
{
/* If not seen before, initialize to UNKNOWN type */
if (toppstate->p_paramtypes[paramno - 1] == InvalidOid)
toppstate->p_paramtypes[paramno - 1] = UNKNOWNOID;
}
param = makeNode(Param);
param->paramkind = PARAM_NUM;
param->paramid = (AttrNumber) paramno;
param->paramtype = toppstate->p_paramtypes[paramno - 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 MULTIEXPR 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 = MULTIEXPR_SUBLINK;
s->lefthand = ((RowExpr *) lexpr)->args;
s->operName = a->name;
result = transformExpr(pstate, (Node *) s);
}
else if (lexpr && IsA(lexpr, RowExpr) &&
rexpr && IsA(rexpr, RowExpr))
{
/* "row op row" */
result = make_row_op(pstate, a->name, lexpr, rexpr);
}
else
{
/* Ordinary scalar operator */
lexpr = transformExpr(pstate, lexpr);
rexpr = transformExpr(pstate, rexpr);
result = (Node *) make_op(pstate,
a->name,
lexpr,
rexpr);
}
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);
}
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);
}
static Node *
transformAExprDistinct(ParseState *pstate, A_Expr *a)
{
Node *lexpr = a->lexpr;
Node *rexpr = a->rexpr;
if (lexpr && IsA(lexpr, RowExpr) &&
rexpr && IsA(rexpr, RowExpr))
{
/* "row op row" */
return make_row_distinct_op(pstate, a->name,
lexpr, rexpr);
}
else
{ /* Ordinary scalar operator */
lexpr = transformExpr(pstate, lexpr);
rexpr = transformExpr(pstate, rexpr);
return (Node *) make_distinct_op(pstate,
a->name,
lexpr,
rexpr);
}
}
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);
if (((OpExpr *) result)->opresulttype != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("NULLIF requires = operator to yield boolean")));
/*
* 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 type. Will result in a boolean
* constant node.
*/
ListCell *telem;
A_Const *n;
Oid ltype,
rtype;
bool matched = false;
Node *lexpr = transformExpr(pstate, a->lexpr);
ltype = exprType(lexpr);
foreach(telem, (List *) a->rexpr)
{
rtype = LookupTypeName(lfirst(telem));
matched = (rtype == ltype);
if (matched)
break;
}
/*
* Expect two forms: equals or not equals. Flip the sense of the result
* for not equals.
*/
if (strcmp(strVal(linitial(a->name)), "!=") == 0)
matched = (!matched);
n = makeNode(A_Const);
n->val.type = T_String;
n->val.val.str = (matched ? "t" : "f");
n->typename = SystemTypeName("bool");
return transformExpr(pstate, (Node *) n);
}
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);
}
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);
}
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->resultRelation != 0)
elog(ERROR, "bad query in sub-select");
sublink->subselect = (Node *) qtree;
if (sublink->subLinkType == EXISTS_SUBLINK)
{
/*
* EXISTS needs no lefthand or combining operator. These fields
* should be NIL already, but make sure.
*/
sublink->lefthand = NIL;
sublink->operName = NIL;
sublink->operOids = NIL;
sublink->useOr = FALSE;
}
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 lefthand or combining operator. These fields
* should be NIL already, but make sure.
*/ sublink->lefthand = NIL;
sublink->operName = NIL;
sublink->operOids = NIL;
sublink->useOr = FALSE;
}
else
{
/* ALL, ANY, or MULTIEXPR: generate operator list */
List *left_list = sublink->lefthand;
List *right_list = qtree->targetList;
int row_length = list_length(left_list);
bool needNot = false;
List *op = sublink->operName;
char *opname = strVal(llast(op));
ListCell *l;
ListCell *ll_item;
/* transform lefthand expressions */
foreach(l, left_list)
lfirst(l) = transformExpr(pstate, lfirst(l));
/*
* If the expression is "<> ALL" (with unqualified opname) then
* convert it to "NOT IN". This is a hack to improve efficiency of
* expressions output by pre-7.4 Postgres.
*/
if (sublink->subLinkType == ALL_SUBLINK &&
list_length(op) == 1 && strcmp(opname, "<>") == 0)
{
sublink->subLinkType = ANY_SUBLINK;
opname = pstrdup("=");
op = list_make1(makeString(opname));
sublink->operName = op;
needNot = true;
}
/* Set useOr if op is "<>" (possibly qualified) */
if (strcmp(opname, "<>") == 0)
sublink->useOr = TRUE;
else
sublink->useOr = FALSE;
/* Combining operators other than =/<> is dubious... */
if (row_length != 1 &&
strcmp(opname, "=") != 0 &&
strcmp(opname, "<>") != 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("row comparison cannot use operator %s",
opname)));
/*
* To build the list of combining operator OIDs, we must scan
* subquery's targetlist to find values that will be matched against
* lefthand values. We need to ignore resjunk targets, so doing the
* outer iteration over right_list is easier than doing it over
* left_list.
*/
sublink->operOids = NIL;
ll_item = list_head(left_list);
foreach(l, right_list)
{
TargetEntry *tent = (TargetEntry *) lfirst(l);
Node *lexpr;
Operator optup;
Form_pg_operator opform;
if (tent->resjunk)
continue;
if (ll_item == NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery has too many columns")));
lexpr = lfirst(ll_item);
ll_item = lnext(ll_item);
/*
* It's OK to use oper() not compatible_oper() here, because
* make_subplan() will insert type coercion calls if needed.
*/
optup = oper(op,
exprType(lexpr),
exprType((Node *) tent->expr),
false);
opform = (Form_pg_operator) GETSTRUCT(optup);
if (opform->oprresult != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("operator %s must return type boolean, not type %s",
opname,
format_type_be(opform->oprresult)),
errhint("The operator of a quantified predicate subquery must return type boolean.")));
if (get_func_retset(opform->oprcode))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("operator %s must not return a set",
opname),
errhint("The operator of a quantified predicate subquery must return type boolean.")));
sublink->operOids = lappend_oid(sublink->operOids,
oprid(optup));
ReleaseSysCache(optup);
}
if (ll_item != NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery has too few columns")));
if (needNot)
{
result = coerce_to_boolean(pstate, result, "NOT");
result = (Node *) makeBoolExpr(NOT_EXPR,
list_make1(result));
}
}
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);
List *newargs = NIL;
ListCell *arg;
/* Transform the field expressions */
foreach(arg, r->args)
{
Node *e = (Node *) lfirst(arg);
Node *newe;
newe = transformExpr(pstate, e);
newargs = lappend(newargs, newe);
}
newr->args = newargs;
/* 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 *
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;
}
/*
* 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)
{
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));
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 (toid == RECORDOID || get_typtype(toid) == 'c')
{
/* 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;
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:
type = ((ArrayRef *) expr)->refrestype;
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 */
TargetEntry *tent;
tent = (TargetEntry *) linitial(subplan->plan->targetlist);
Assert(IsA(tent, TargetEntry));
Assert(!tent->resjunk);
type = exprType((Node *) tent->expr);
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(exprType((Node *) tent->expr)))));
}
}
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_ConvertRowtypeExpr:
type = ((ConvertRowtypeExpr *) expr)->resulttype;
break;
case T_CaseExpr:
type = ((CaseExpr *) expr)->casetype;
break;
case T_CaseWhen:
type = exprType((Node *) ((CaseWhen *) expr)->result);
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_CoalesceExpr: type = ((CoalesceExpr *) expr)->coalescetype;
break;
case T_MinMaxExpr:
type = ((MinMaxExpr *) expr)->minmaxtype;
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;
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:
{
/* Be smart about string constants... */
Const *con = (Const *) expr;
switch (con->consttype)
{
case BPCHAROID:
if (!con->constisnull)
{
int32 len = VARSIZE(DatumGetPointer(con->constvalue)) - VARHDRSZ;
/* if multi-byte, take len and find # characters */
if (pg_database_encoding_max_length() > 1)
len = pg_mbstrlen_with_len(VARDATA(DatumGetPointer(con->constvalue)), len);
return len + VARHDRSZ;
}
break;
default:
break;
}
}
break;
case T_FuncExpr: {
int32 coercedTypmod;
/* Be smart about length-coercion functions... */
if (exprIsLengthCoercion(expr, &coercedTypmod))
return coercedTypmod;
}
break;
case T_FieldSelect:
return ((FieldSelect *) expr)->resulttypmod;
case T_RelabelType:
return ((RelabelType *) 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_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)
{
FuncExpr *func;
int nargs;
Const *second_arg;
if (coercedTypmod != NULL)
*coercedTypmod = -1; /* default result on failure */
/* Is it a function-call at all? */
if (expr == NULL || !IsA(expr, FuncExpr))
return false;
func = (FuncExpr *) expr;
/*
* 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;
}
/*
* 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;
targetType = typenameTypeId(typename);
if (inputType == InvalidOid)
return expr; /* do nothing if NULL input */
expr = coerce_to_target_type(pstate, expr, inputType,
targetType, typename->typmod,
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))));
return expr;
}
/*
* Transform a "row op row" construct */
static Node *
make_row_op(ParseState *pstate, List *opname, Node *ltree, Node *rtree)
{
Node *result = NULL;
RowExpr *lrow,
*rrow;
List *largs,
*rargs;
ListCell *l,
*r;
char *oprname;
BoolExprType boolop;
/* Inputs are untransformed RowExprs */
lrow = (RowExpr *) transformExpr(pstate, ltree);
rrow = (RowExpr *) transformExpr(pstate, rtree);
Assert(IsA(lrow, RowExpr));
Assert(IsA(rrow, RowExpr));
largs = lrow->args;
rargs = rrow->args;
if (list_length(largs) != list_length(rargs))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unequal number of entries in row expression")));
/*
* XXX it's really wrong to generate a simple AND combination for < <= >
* >=. We probably need to invent a new runtime node type to handle those
* correctly. For the moment, though, keep on doing this ...
*/
oprname = strVal(llast(opname));
if ((strcmp(oprname, "=") == 0) ||
(strcmp(oprname, "<") == 0) ||
(strcmp(oprname, "<=") == 0) ||
(strcmp(oprname, ">") == 0) ||
(strcmp(oprname, ">=") == 0))
boolop = AND_EXPR;
else if (strcmp(oprname, "<>") == 0)
boolop = OR_EXPR;
else
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("operator %s is not supported for row expressions",
oprname)));
boolop = 0; /* keep compiler quiet */
}
forboth(l, largs, r, rargs)
{
Node *larg = (Node *) lfirst(l);
Node *rarg = (Node *) lfirst(r);
Node *cmp;
cmp = (Node *) make_op(pstate, opname, larg, rarg);
cmp = coerce_to_boolean(pstate, cmp, "row comparison");
if (result == NULL)
result = cmp;
else
result = (Node *) makeBoolExpr(boolop,
list_make2(result, cmp));
}
if (result == NULL)
{
/* zero-length rows? Generate constant TRUE or FALSE */
if (boolop == AND_EXPR) result = makeBoolConst(true, false);
else
result = makeBoolConst(false, false);
}
return result;
}
/*
* Transform a "row IS DISTINCT FROM row" construct
*/
static Node *
make_row_distinct_op(ParseState *pstate, List *opname,
Node *ltree, Node *rtree)
{
Node *result = NULL;
RowExpr *lrow,
*rrow;
List *largs,
*rargs;
ListCell *l,
*r;
/* Inputs are untransformed RowExprs */
lrow = (RowExpr *) transformExpr(pstate, ltree);
rrow = (RowExpr *) transformExpr(pstate, rtree);
Assert(IsA(lrow, RowExpr));
Assert(IsA(rrow, RowExpr));
largs = lrow->args;
rargs = rrow->args;
if (list_length(largs) != list_length(rargs))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unequal number of entries in row expression")));
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);
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)
{
Expr *result;
result = make_op(pstate, opname, ltree, rtree);
if (((OpExpr *) result)->opresulttype != BOOLOID)
ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("IS DISTINCT FROM requires = operator to yield boolean")));
/*
* We rely on DistinctExpr and OpExpr being same struct
*/
NodeSetTag(result, T_DistinctExpr);
return result;
}