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postgres/src/backend/parser/parse_func.c
Thomas G. Lockhart 681c587d22 Do a better job of selecting candidates among functions 
when no exact match.
Clean up elog error messages.
1999-02-23 07:51:53 +00:00

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/*-------------------------------------------------------------------------
*
* parse_func.c
* handle function calls in parser
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/parser/parse_func.c,v 1.39 1999/02/23 07:51:53 thomas Exp $
*
*-------------------------------------------------------------------------
*/
#include <string.h>
#include "postgres.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/itup.h"
#include "access/relscan.h"
#include "access/sdir.h"
#include "catalog/catname.h"
#include "catalog/indexing.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "catalog/pg_aggregate.h"
#include "fmgr.h"
#include "lib/dllist.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/relation.h"
#include "parser/parse_agg.h"
#include "parser/parse_expr.h"
#include "parser/parse_func.h"
#include "parser/parse_node.h"
#include "parser/parse_relation.h"
#include "parser/parse_target.h"
#include "parser/parse_type.h"
#include "parser/parse_coerce.h"
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
static Node *ParseComplexProjection(ParseState *pstate,
char *funcname,
Node *first_arg,
bool *attisset);
static Oid **argtype_inherit(int nargs, Oid *oid_array);
static int find_inheritors(Oid relid, Oid **supervec);
static CandidateList func_get_candidates(char *funcname, int nargs);
static bool
func_get_detail(char *funcname,
int nargs,
Oid *oid_array,
Oid *funcid, /* return value */
Oid *rettype, /* return value */
bool *retset, /* return value */
Oid **true_typeids);
static Oid funcid_get_rettype(Oid funcid);
static Oid **gen_cross_product(InhPaths *arginh, int nargs);
static void make_arguments(ParseState *pstate,
int nargs,
List *fargs,
Oid *input_typeids,
Oid *function_typeids);
static int match_argtypes(int nargs,
Oid *input_typeids,
CandidateList function_typeids,
CandidateList *candidates);
static List *setup_tlist(char *attname, Oid relid);
static List *setup_base_tlist(Oid typeid);
static Oid *func_select_candidate(int nargs, Oid *input_typeids,
CandidateList candidates);
static int agg_get_candidates(char *aggname, Oid typeId, CandidateList *candidates);
static Oid agg_select_candidate(Oid typeid, CandidateList candidates);
#define ISCOMPLEX(type) (typeidTypeRelid(type) ? true : false)
#define MAXFARGS 8 /* max # args to a c or postquel function */
typedef struct _SuperQE
{
Oid sqe_relid;
} SuperQE;
/*
** ParseNestedFuncOrColumn
** Given a nested dot expression (i.e. (relation func ... attr), build up
** a tree with of Iter and Func nodes.
*/
Node *
ParseNestedFuncOrColumn(ParseState *pstate, Attr *attr, int *curr_resno, int precedence)
{
List *mutator_iter;
Node *retval = NULL;
if (attr->paramNo != NULL)
{
Param *param = (Param *) transformExpr(pstate, (Node *) attr->paramNo, EXPR_RELATION_FIRST);
retval = ParseFuncOrColumn(pstate, strVal(lfirst(attr->attrs)),
lcons(param, NIL),
curr_resno,
precedence);
}
else
{
Ident *ident = makeNode(Ident);
ident->name = attr->relname;
ident->isRel = TRUE;
retval = ParseFuncOrColumn(pstate, strVal(lfirst(attr->attrs)),
lcons(ident, NIL),
curr_resno,
precedence);
}
/* Do more attributes follow this one? */
foreach(mutator_iter, lnext(attr->attrs))
{
retval = ParseFuncOrColumn(pstate, strVal(lfirst(mutator_iter)),
lcons(retval, NIL),
curr_resno,
precedence);
}
return retval;
}
static int
agg_get_candidates(char *aggname,
Oid typeId,
CandidateList *candidates)
{
CandidateList current_candidate;
Relation pg_aggregate_desc;
HeapScanDesc pg_aggregate_scan;
HeapTuple tup;
Form_pg_aggregate agg;
int ncandidates = 0;
static ScanKeyData aggKey[1] = {
{0, Anum_pg_aggregate_aggname, F_NAMEEQ}};
*candidates = NULL;
fmgr_info(F_NAMEEQ, (FmgrInfo *) &aggKey[0].sk_func);
aggKey[0].sk_argument = NameGetDatum(aggname);
pg_aggregate_desc = heap_openr(AggregateRelationName);
pg_aggregate_scan = heap_beginscan(pg_aggregate_desc,
0,
SnapshotSelf, /* ??? */
1,
aggKey);
while (HeapTupleIsValid(tup = heap_getnext(pg_aggregate_scan, 0)))
{
current_candidate = (CandidateList) palloc(sizeof(struct _CandidateList));
current_candidate->args = (Oid *) palloc(sizeof(Oid));
agg = (Form_pg_aggregate) GETSTRUCT(tup);
current_candidate->args[0] = agg->aggbasetype;
current_candidate->next = *candidates;
*candidates = current_candidate;
ncandidates++;
}
heap_endscan(pg_aggregate_scan);
heap_close(pg_aggregate_desc);
return ncandidates;
} /* agg_get_candidates() */
/* agg_select_candidate()
* Try to choose only one candidate aggregate function from a list of possibles.
*/
static Oid
agg_select_candidate(Oid typeid, CandidateList candidates)
{
CandidateList current_candidate;
CandidateList last_candidate;
Oid current_typeid;
int ncandidates;
CATEGORY category,
current_category;
/*
* Look for candidates which allow coersion and have a preferred type.
* Keep all candidates if none match.
*/
category = TypeCategory(typeid);
ncandidates = 0;
last_candidate = NULL;
for (current_candidate = candidates;
current_candidate != NULL;
current_candidate = current_candidate->next)
{
current_typeid = current_candidate->args[0];
current_category = TypeCategory(current_typeid);
if ((current_category == category)
&& IsPreferredType(current_category, current_typeid)
&& can_coerce_type(1, &typeid, &current_typeid))
{
/* only one so far? then keep it... */
if (last_candidate == NULL)
{
candidates = current_candidate;
last_candidate = current_candidate;
ncandidates = 1;
}
/* otherwise, keep this one too... */
else
{
last_candidate->next = current_candidate;
last_candidate = current_candidate;
ncandidates++;
}
}
/* otherwise, don't bother keeping this one around... */
else if (last_candidate != NULL)
{
last_candidate->next = NULL;
}
}
return ((ncandidates == 1) ? candidates->args[0] : 0);
} /* agg_select_candidate() */
/*
* parse function
*/
Node *
ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
int *curr_resno, int precedence)
{
Oid rettype = (Oid) 0;
Oid argrelid = (Oid) 0;
Oid funcid = (Oid) 0;
List *i = NIL;
Node *first_arg = NULL;
char *relname = NULL;
char *refname = NULL;
Relation rd;
Oid relid;
int nargs;
Func *funcnode;
Oid oid_array[8];
Oid *true_oid_array;
Node *retval;
bool retset;
bool attisset = false;
Oid toid = (Oid) 0;
Expr *expr;
if (fargs)
{
first_arg = lfirst(fargs);
if (first_arg == NULL)
elog(ERROR, "Function '%s' does not allow NULL input", funcname);
}
/*
* check for projection methods: if function takes one argument, and
* that argument is a relation, param, or PQ function returning a
* complex * type, then the function could be a projection.
*/
/* We only have one parameter */
if (length(fargs) == 1)
{
/* Is is a plain Relation name from the parser? */
if (nodeTag(first_arg) == T_Ident && ((Ident *) first_arg)->isRel)
{
RangeTblEntry *rte;
Ident *ident = (Ident *) first_arg;
/*
* first arg is a relation. This could be a projection.
*/
refname = ident->name;
rte = refnameRangeTableEntry(pstate, refname);
if (rte == NULL)
rte = addRangeTableEntry(pstate, refname, refname, FALSE, FALSE);
relname = rte->relname;
relid = rte->relid;
/*
* If the attr isn't a set, just make a var for it. If it is
* a set, treat it like a function and drop through.
*/
if (get_attnum(relid, funcname) != InvalidAttrNumber)
{
return (Node *) make_var(pstate,
relid,
refname,
funcname);
}
else
{
/* drop through - attr is a set */
;
}
}
else if (ISCOMPLEX(exprType(first_arg)))
{
/*
* Attempt to handle projection of a complex argument. If
* ParseComplexProjection can't handle the projection, we have
* to keep going.
*/
retval = ParseComplexProjection(pstate,
funcname,
first_arg,
&attisset);
if (attisset)
{
toid = exprType(first_arg);
rd = heap_openr(typeidTypeName(toid));
if (RelationIsValid(rd))
{
relname = RelationGetRelationName(rd)->data;
heap_close(rd);
}
else
elog(ERROR, "Type '%s' is not a relation type",
typeidTypeName(toid));
argrelid = typeidTypeRelid(toid);
/*
* A projection contains either an attribute name or the
* "*".
*/
if ((get_attnum(argrelid, funcname) == InvalidAttrNumber)
&& strcmp(funcname, "*"))
elog(ERROR, "Functions on sets are not yet supported");
}
if (retval)
return retval;
}
else
{
/*
* Parsing aggregates.
*/
Type tp;
Oid basetype;
int ncandidates;
CandidateList candidates;
/*
* the aggregate COUNT is a special case, ignore its base
* type. Treat it as zero
*/
if (strcmp(funcname, "count") == 0)
basetype = 0;
else
basetype = exprType(lfirst(fargs));
/* try for exact match first... */
if (SearchSysCacheTuple(AGGNAME,
PointerGetDatum(funcname),
ObjectIdGetDatum(basetype),
0, 0))
return (Node *) ParseAgg(pstate, funcname, basetype,
fargs, precedence);
/*
* No exact match yet, so see if there is another entry
* in the aggregate table which is compatible.
* - thomas 1998-12-05
*/
ncandidates = agg_get_candidates(funcname, basetype, &candidates);
if (ncandidates > 0)
{
Oid type;
type = agg_select_candidate(basetype, candidates);
if (OidIsValid(type))
{
lfirst(fargs) = coerce_type(pstate, lfirst(fargs), basetype, type);
basetype = type;
return (Node *) ParseAgg(pstate, funcname, basetype,
fargs, precedence);
}
else
{
elog(ERROR,"Unable to select an aggregate function %s(%s)",
funcname, typeidTypeName(basetype));
}
}
/*
* See if this is a single argument function with the function
* name also a type name and the input argument and type name
* binary compatible...
* This means that you are trying for a type conversion which does not
* need to take place, so we'll just pass through the argument itself.
* (make this clearer with some extra brackets - thomas 1998-12-05)
*/
if ((HeapTupleIsValid(tp = SearchSysCacheTuple(TYPNAME,
PointerGetDatum(funcname),
0, 0, 0)))
&& IS_BINARY_COMPATIBLE(typeTypeId(tp), basetype))
{
return ((Node *) lfirst(fargs));
}
}
}
/*
* If we dropped through to here it's really a function (or a set,
* which is implemented as a function). Extract arg type info and
* transform relation name arguments into varnodes of the appropriate
* form.
*/
MemSet(&oid_array[0], 0, 8 * sizeof(Oid));
nargs = 0;
foreach(i, fargs)
{
int vnum;
RangeTblEntry *rte;
Node *pair = lfirst(i);
if (nodeTag(pair) == T_Ident && ((Ident *) pair)->isRel)
{
/*
* a relation
*/
refname = ((Ident *) pair)->name;
rte = refnameRangeTableEntry(pstate, refname);
if (rte == NULL)
rte = addRangeTableEntry(pstate, refname, refname,
FALSE, FALSE);
relname = rte->relname;
vnum = refnameRangeTablePosn(pstate, rte->refname, NULL);
/*
* for func(relname), the param to the function is the tuple
* under consideration. we build a special VarNode to reflect
* this -- it has varno set to the correct range table entry,
* but has varattno == 0 to signal that the whole tuple is the
* argument.
*/
toid = typeTypeId(typenameType(relname));
/* replace it in the arg list */
lfirst(fargs) = makeVar(vnum, 0, toid, -1, 0, vnum, 0);
}
else if (!attisset)
{ /* set functions don't have parameters */
/*
* any functiona args which are typed "unknown", but aren't
* constants, we don't know what to do with, because we can't
* cast them - jolly
*/
if (exprType(pair) == UNKNOWNOID && !IsA(pair, Const))
elog(ERROR, "There is no function '%s'"
" with argument #%d of type UNKNOWN",
funcname, nargs);
else
toid = exprType(pair);
}
oid_array[nargs++] = toid;
}
/*
* func_get_detail looks up the function in the catalogs, does
* disambiguation for polymorphic functions, handles inheritance, and
* returns the funcid and type and set or singleton status of the
* function's return value. it also returns the true argument types
* to the function. if func_get_detail returns true, the function
* exists. otherwise, there was an error.
*/
if (attisset)
{ /* we know all of these fields already */
/*
* We create a funcnode with a placeholder function SetEval.
* SetEval() never actually gets executed. When the function
* evaluation routines see it, they use the funcid projected out
* from the relation as the actual function to call. Example:
* retrieve (emp.mgr.name) The plan for this will scan the emp
* relation, projecting out the mgr attribute, which is a funcid.
* This function is then called (instead of SetEval) and "name" is
* projected from its result.
*/
funcid = F_SETEVAL;
rettype = toid;
retset = true;
true_oid_array = oid_array;
}
else
{
bool exists;
exists = func_get_detail(funcname, nargs, oid_array, &funcid,
&rettype, &retset, &true_oid_array);
if (!exists)
elog(ERROR, "No such function '%s' with the specified attributes",
funcname);
}
/* got it */
funcnode = makeNode(Func);
funcnode->funcid = funcid;
funcnode->functype = rettype;
funcnode->funcisindex = false;
funcnode->funcsize = 0;
funcnode->func_fcache = NULL;
funcnode->func_tlist = NIL;
funcnode->func_planlist = NIL;
/* perform the necessary typecasting */
make_arguments(pstate, nargs, fargs, oid_array, true_oid_array);
/*
* for functions returning base types, we want to project out the
* return value. set up a target list to do that. the executor will
* ignore these for c functions, and do the right thing for postquel
* functions.
*/
if (typeidTypeRelid(rettype) == InvalidOid)
funcnode->func_tlist = setup_base_tlist(rettype);
/*
* For sets, we want to make a targetlist to project out this
* attribute of the set tuples.
*/
if (attisset)
{
if (!strcmp(funcname, "*"))
{
funcnode->func_tlist = expandAll(pstate, relname, refname, curr_resno);
}
else
{
funcnode->func_tlist = setup_tlist(funcname, argrelid);
rettype = get_atttype(argrelid, get_attnum(argrelid, funcname));
}
}
/*
* Sequence handling.
*/
if (funcid == F_NEXTVAL ||
funcid == F_CURRVAL ||
funcid == F_SETVAL)
{
Const *seq;
char *seqrel;
text *seqname;
int32 aclcheck_result = -1;
extern text *lower(text *string);
Assert(length(fargs) == ((funcid == F_SETVAL) ? 2 : 1));
seq = (Const *) lfirst(fargs);
if (!IsA((Node *) seq, Const))
elog(ERROR, "Only constant sequence names are acceptable for function '%s'", funcname);
seqname = lower((text *) DatumGetPointer(seq->constvalue));
pfree(DatumGetPointer(seq->constvalue));
seq->constvalue = PointerGetDatum(seqname);
seqrel = textout(seqname);
if ((aclcheck_result = pg_aclcheck(seqrel, GetPgUserName(),
(((funcid == F_NEXTVAL) || (funcid == F_SETVAL)) ?
ACL_WR : ACL_RD)))
!= ACLCHECK_OK)
elog(ERROR, "%s.%s: %s",
seqrel, funcname, aclcheck_error_strings[aclcheck_result]);
pfree(seqrel);
if (funcid == F_NEXTVAL && pstate->p_in_where_clause)
elog(ERROR, "Sequence function nextval is not allowed in WHERE clauses");
if (funcid == F_SETVAL && pstate->p_in_where_clause)
elog(ERROR, "Sequence function setval is not allowed in WHERE clauses");
}
expr = makeNode(Expr);
expr->typeOid = rettype;
expr->opType = FUNC_EXPR;
expr->oper = (Node *) funcnode;
expr->args = fargs;
retval = (Node *) expr;
/*
* if the function returns a set of values, then we need to iterate
* over all the returned values in the executor, so we stick an iter
* node here. if it returns a singleton, then we don't need the iter
* node.
*/
if (retset)
{
Iter *iter = makeNode(Iter);
iter->itertype = rettype;
iter->iterexpr = retval;
retval = (Node *) iter;
}
return retval;
}
static Oid
funcid_get_rettype(Oid funcid)
{
HeapTuple func_tuple = NULL;
Oid funcrettype = (Oid) 0;
func_tuple = SearchSysCacheTuple(PROOID,
ObjectIdGetDatum(funcid),
0, 0, 0);
if (!HeapTupleIsValid(func_tuple))
elog(ERROR, "Function OID %d does not exist", funcid);
funcrettype = (Oid)
((Form_pg_proc) GETSTRUCT(func_tuple))->prorettype;
return funcrettype;
}
/* func_get_candidates()
* get a list of all argument type vectors for which a function named
* funcname taking nargs arguments exists
*/
static CandidateList
func_get_candidates(char *funcname, int nargs)
{
Relation heapRelation;
Relation idesc;
ScanKeyData skey;
HeapTupleData tuple;
IndexScanDesc sd;
RetrieveIndexResult indexRes;
Form_pg_proc pgProcP;
CandidateList candidates = NULL;
CandidateList current_candidate;
int i;
heapRelation = heap_openr(ProcedureRelationName);
ScanKeyEntryInitialize(&skey,
(bits16) 0x0,
(AttrNumber) 1,
(RegProcedure) F_NAMEEQ,
(Datum) funcname);
idesc = index_openr(ProcedureNameIndex);
sd = index_beginscan(idesc, false, 1, &skey);
do
{
indexRes = index_getnext(sd, ForwardScanDirection);
if (indexRes)
{
Buffer buffer;
tuple.t_self = indexRes->heap_iptr;
heap_fetch(heapRelation, SnapshotNow, &tuple, &buffer);
pfree(indexRes);
if (tuple.t_data != NULL)
{
pgProcP = (Form_pg_proc) GETSTRUCT(&tuple);
if (pgProcP->pronargs == nargs)
{
current_candidate = (CandidateList)
palloc(sizeof(struct _CandidateList));
current_candidate->args = (Oid *)
palloc(8 * sizeof(Oid));
MemSet(current_candidate->args, 0, 8 * sizeof(Oid));
for (i = 0; i < nargs; i++)
current_candidate->args[i] = pgProcP->proargtypes[i];
current_candidate->next = candidates;
candidates = current_candidate;
}
ReleaseBuffer(buffer);
}
}
} while (indexRes);
index_endscan(sd);
index_close(idesc);
heap_close(heapRelation);
return candidates;
}
/* match_argtypes()
* Given a list of possible typeid arrays to a function and an array of
* input typeids, produce a shortlist of those function typeid arrays
* that match the input typeids (either exactly or by coercion), and
* return the number of such arrays
*/
static int
match_argtypes(int nargs,
Oid *input_typeids,
CandidateList function_typeids,
CandidateList *candidates) /* return value */
{
CandidateList current_candidate;
CandidateList matching_candidate;
Oid *current_typeids;
int ncandidates = 0;
*candidates = NULL;
for (current_candidate = function_typeids;
current_candidate != NULL;
current_candidate = current_candidate->next)
{
current_typeids = current_candidate->args;
if (can_coerce_type(nargs, input_typeids, current_typeids))
{
matching_candidate = (CandidateList)
palloc(sizeof(struct _CandidateList));
matching_candidate->args = current_typeids;
matching_candidate->next = *candidates;
*candidates = matching_candidate;
ncandidates++;
}
}
return ncandidates;
} /* match_argtypes() */
/* func_select_candidate()
* Given the input argtype array and more than one candidate
* for the function argtype array, attempt to resolve the conflict.
* returns the selected argtype array if the conflict can be resolved,
* otherwise returns NULL.
*
* If all input Oids are UNKNOWNOID, then try matching with TEXTOID.
* Otherwise, could return first function arguments on list of candidates.
* But for now, return NULL and make the user give a better hint.
* - thomas 1998-03-17
*/
static Oid *
func_select_candidate(int nargs,
Oid *input_typeids,
CandidateList candidates)
{
CandidateList current_candidate;
CandidateList last_candidate;
Oid *current_typeids;
int i;
int ncandidates;
int nbestMatch,
nmatch,
nident;
CATEGORY slot_category,
current_category;
Oid slot_type,
current_type;
/*
* Run through all candidates and keep those with the most matches
* on explicit types. Keep all candidates if none match.
*/
ncandidates = 0;
nbestMatch = 0;
last_candidate = NULL;
for (current_candidate = candidates;
current_candidate != NULL;
current_candidate = current_candidate->next)
{
current_typeids = current_candidate->args;
nmatch = 0;
nident = 0;
for (i = 0; i < nargs; i++)
{
if ((input_typeids[i] != UNKNOWNOID)
&& (current_typeids[i] == input_typeids[i]))
nmatch++;
else if (IS_BINARY_COMPATIBLE(current_typeids[i], input_typeids[i]))
nident++;
}
if ((nmatch + nident) == nargs)
return current_candidate->args;
if ((nmatch > nbestMatch) || (last_candidate == NULL))
{
nbestMatch = nmatch;
candidates = current_candidate;
last_candidate = current_candidate;
ncandidates = 1;
}
else if (nmatch == nbestMatch)
{
last_candidate->next = current_candidate;
last_candidate = current_candidate;
ncandidates++;
}
else
{
last_candidate->next = NULL;
}
}
if (ncandidates == 1)
return candidates->args;
/*
* Still too many candidates?
* Try assigning types for the unknown columns.
*/
for (i = 0; i < nargs; i++)
{
if (input_typeids[i] == UNKNOWNOID)
{
slot_category = INVALID_TYPE;
slot_type = InvalidOid;
for (current_candidate = candidates;
current_candidate != NULL;
current_candidate = current_candidate->next)
{
current_typeids = current_candidate->args;
current_type = current_typeids[i];
current_category = TypeCategory(current_typeids[i]);
if (slot_category == InvalidOid)
{
slot_category = current_category;
slot_type = current_type;
}
else if ((current_category != slot_category)
&& IS_BUILTIN_TYPE(current_type))
{
return NULL;
}
else if (current_type != slot_type)
{
if (IsPreferredType(slot_category, current_type))
{
slot_type = current_type;
candidates = current_candidate;
}
else if (IsPreferredType(slot_category, slot_type))
{
candidates->next = current_candidate->next;
}
}
}
if (slot_type != InvalidOid)
{
input_typeids[i] = slot_type;
}
}
else
{
}
}
ncandidates = 0;
for (current_candidate = candidates;
current_candidate != NULL;
current_candidate = current_candidate->next)
ncandidates++;
if (ncandidates == 1)
return candidates->args;
return NULL;
} /* func_select_candidate() */
/* func_get_detail()
* Find the named function in the system catalogs.
*
* Attempt to find the named function in the system catalogs with
* arguments exactly as specified, so that the normal case
* (exact match) is as quick as possible.
*
* If an exact match isn't found:
* 1) get a vector of all possible input arg type arrays constructed
* from the superclasses of the original input arg types
* 2) get a list of all possible argument type arrays to the function
* with given name and number of arguments
* 3) for each input arg type array from vector #1:
* a) find how many of the function arg type arrays from list #2
* it can be coerced to
* b) if the answer is one, we have our function
* c) if the answer is more than one, attempt to resolve the conflict
* d) if the answer is zero, try the next array from vector #1
*/
static bool
func_get_detail(char *funcname,
int nargs,
Oid *oid_array,
Oid *funcid, /* return value */
Oid *rettype, /* return value */
bool *retset, /* return value */
Oid **true_typeids) /* return value */
{
Oid **input_typeid_vector;
Oid *current_input_typeids;
CandidateList function_typeids;
CandidateList current_function_typeids;
HeapTuple ftup;
Form_pg_proc pform;
/* attempt to find with arguments exactly as specified... */
ftup = SearchSysCacheTuple(PRONAME,
PointerGetDatum(funcname),
Int32GetDatum(nargs),
PointerGetDatum(oid_array),
0);
*true_typeids = oid_array;
/* didn't find an exact match, so now try to match up candidates... */
if (!HeapTupleIsValid(ftup))
{
function_typeids = func_get_candidates(funcname, nargs);
/* found something, so let's look through them... */
if (function_typeids != NULL)
{
int ncandidates;
input_typeid_vector = argtype_inherit(nargs, oid_array);
current_input_typeids = oid_array;
do
{
ncandidates = match_argtypes(nargs, current_input_typeids,
function_typeids,
&current_function_typeids);
/* one match only? then run with it... */
if (ncandidates == 1)
{
*true_typeids = current_function_typeids->args;
ftup = SearchSysCacheTuple(PRONAME,
PointerGetDatum(funcname),
Int32GetDatum(nargs),
PointerGetDatum(*true_typeids),
0);
Assert(HeapTupleIsValid(ftup));
}
/*
* multiple candidates? then better decide or throw an
* error...
*/
else if (ncandidates > 1)
{
*true_typeids = func_select_candidate(nargs,
current_input_typeids,
current_function_typeids);
/* couldn't decide, so quit */
if (*true_typeids == NULL)
{
func_error(NULL, funcname, nargs, oid_array,
"Unable to identify a function which satisfies the given argument types"
"\n\tYou will have to retype your query using explicit typecasts");
}
/* found something, so use the first one... */
else
{
ftup = SearchSysCacheTuple(PRONAME,
PointerGetDatum(funcname),
Int32GetDatum(nargs),
PointerGetDatum(*true_typeids),
0);
Assert(HeapTupleIsValid(ftup));
}
}
current_input_typeids = *input_typeid_vector++;
}
while (current_input_typeids != InvalidOid && ncandidates == 0);
}
}
if (!HeapTupleIsValid(ftup))
{
Type tp;
if (nargs == 1)
{
tp = typeidType(oid_array[0]);
if (typeTypeFlag(tp) == 'c')
elog(ERROR, "No such attribute or function '%s'", funcname);
}
}
else
{
pform = (Form_pg_proc) GETSTRUCT(ftup);
*funcid = ftup->t_data->t_oid;
*rettype = pform->prorettype;
*retset = pform->proretset;
return true;
}
/* shouldn't reach here */
return false;
} /* func_get_detail() */
/*
* argtype_inherit() -- Construct an argtype vector reflecting the
* inheritance properties of the supplied argv.
*
* This function is used to disambiguate among functions with the
* same name but different signatures. It takes an array of eight
* type ids. For each type id in the array that's a complex type
* (a class), it walks up the inheritance tree, finding all
* superclasses of that type. A vector of new Oid type arrays
* is returned to the caller, reflecting the structure of the
* inheritance tree above the supplied arguments.
*
* The order of this vector is as follows: all superclasses of the
* rightmost complex class are explored first. The exploration
* continues from right to left. This policy means that we favor
* keeping the leftmost argument type as low in the inheritance tree
* as possible. This is intentional; it is exactly what we need to
* do for method dispatch. The last type array we return is all
* zeroes. This will match any functions for which return types are
* not defined. There are lots of these (mostly builtins) in the
* catalogs.
*/
static Oid **
argtype_inherit(int nargs, Oid *oid_array)
{
Oid relid;
int i;
InhPaths arginh[MAXFARGS];
for (i = 0; i < MAXFARGS; i++)
{
if (i < nargs)
{
arginh[i].self = oid_array[i];
if ((relid = typeidTypeRelid(oid_array[i])) != InvalidOid)
arginh[i].nsupers = find_inheritors(relid, &(arginh[i].supervec));
else
{
arginh[i].nsupers = 0;
arginh[i].supervec = (Oid *) NULL;
}
}
else
{
arginh[i].self = InvalidOid;
arginh[i].nsupers = 0;
arginh[i].supervec = (Oid *) NULL;
}
}
/* return an ordered cross-product of the classes involved */
return gen_cross_product(arginh, nargs);
}
static int
find_inheritors(Oid relid, Oid **supervec)
{
Oid *relidvec;
Relation inhrel;
HeapScanDesc inhscan;
ScanKeyData skey;
HeapTuple inhtup;
TupleDesc inhtupdesc;
int nvisited;
SuperQE *qentry,
*vnode;
Dllist *visited,
*queue;
Dlelem *qe,
*elt;
Relation rd;
Datum d;
bool newrelid;
char isNull;
nvisited = 0;
queue = DLNewList();
visited = DLNewList();
inhrel = heap_openr(InheritsRelationName);
inhtupdesc = RelationGetDescr(inhrel);
/*
* Use queue to do a breadth-first traversal of the inheritance graph
* from the relid supplied up to the root.
*/
do
{
ScanKeyEntryInitialize(&skey, 0x0, Anum_pg_inherits_inhrel,
F_OIDEQ,
ObjectIdGetDatum(relid));
inhscan = heap_beginscan(inhrel, 0, SnapshotNow, 1, &skey);
while (HeapTupleIsValid(inhtup = heap_getnext(inhscan, 0)))
{
qentry = (SuperQE *) palloc(sizeof(SuperQE));
d = fastgetattr(inhtup, Anum_pg_inherits_inhparent,
inhtupdesc, &isNull);
qentry->sqe_relid = DatumGetObjectId(d);
/* put this one on the queue */
DLAddTail(queue, DLNewElem(qentry));
}
heap_endscan(inhscan);
/* pull next unvisited relid off the queue */
do
{
qe = DLRemHead(queue);
qentry = qe ? (SuperQE *) DLE_VAL(qe) : NULL;
if (qentry == (SuperQE *) NULL)
break;
relid = qentry->sqe_relid;
newrelid = true;
for (elt = DLGetHead(visited); elt; elt = DLGetSucc(elt))
{
vnode = (SuperQE *) DLE_VAL(elt);
if (vnode && (qentry->sqe_relid == vnode->sqe_relid))
{
newrelid = false;
break;
}
}
} while (!newrelid);
if (qentry != (SuperQE *) NULL)
{
/* save the type id, rather than the relation id */
if ((rd = heap_open(qentry->sqe_relid)) == (Relation) NULL)
elog(ERROR, "Relid %d does not exist", qentry->sqe_relid);
qentry->sqe_relid = typeTypeId(typenameType(RelationGetRelationName(rd)->data));
heap_close(rd);
DLAddTail(visited, qe);
nvisited++;
}
} while (qentry != (SuperQE *) NULL);
heap_close(inhrel);
if (nvisited > 0)
{
relidvec = (Oid *) palloc(nvisited * sizeof(Oid));
*supervec = relidvec;
for (elt = DLGetHead(visited); elt; elt = DLGetSucc(elt))
{
vnode = (SuperQE *) DLE_VAL(elt);
*relidvec++ = vnode->sqe_relid;
}
}
else
*supervec = (Oid *) NULL;
return nvisited;
}
static Oid **
gen_cross_product(InhPaths *arginh, int nargs)
{
int nanswers;
Oid **result,
**iter;
Oid *oneres;
int i,
j;
int cur[MAXFARGS];
nanswers = 1;
for (i = 0; i < nargs; i++)
{
nanswers *= (arginh[i].nsupers + 2);
cur[i] = 0;
}
iter = result = (Oid **) palloc(sizeof(Oid *) * nanswers);
/* compute the cross product from right to left */
for (;;)
{
oneres = (Oid *) palloc(MAXFARGS * sizeof(Oid));
MemSet(oneres, 0, MAXFARGS * sizeof(Oid));
for (i = nargs - 1; i >= 0 && cur[i] > arginh[i].nsupers; i--)
continue;
/* if we're done, terminate with NULL pointer */
if (i < 0)
{
*iter = NULL;
return result;
}
/* no, increment this column and zero the ones after it */
cur[i] = cur[i] + 1;
for (j = nargs - 1; j > i; j--)
cur[j] = 0;
for (i = 0; i < nargs; i++)
{
if (cur[i] == 0)
oneres[i] = arginh[i].self;
else if (cur[i] > arginh[i].nsupers)
oneres[i] = 0; /* wild card */
else
oneres[i] = arginh[i].supervec[cur[i] - 1];
}
*iter++ = oneres;
}
}
/* make_arguments()
* Given the number and types of arguments to a function, and the
* actual arguments and argument types, do the necessary typecasting.
*
* There are two ways an input typeid can differ from a function typeid:
* 1) the input type inherits the function type, so no typecasting required
* 2) the input type can be typecast into the function type
* Right now, we only typecast unknowns, and that is all we check for.
*
* func_get_detail() now can find coersions for function arguments which
* will make this function executable. So, we need to recover these
* results here too.
* - thomas 1998-03-25
*/
static void
make_arguments(ParseState *pstate,
int nargs,
List *fargs,
Oid *input_typeids,
Oid *function_typeids)
{
List *current_fargs;
int i;
for (i = 0, current_fargs = fargs;
i < nargs;
i++, current_fargs = lnext(current_fargs))
{
/*
* unspecified type for string constant? then use heuristics for
* conversion...
*/
if (input_typeids[i] == UNKNOWNOID && function_typeids[i] != InvalidOid)
{
lfirst(current_fargs) = parser_typecast2(lfirst(current_fargs),
input_typeids[i],
typeidType(function_typeids[i]),
-1);
}
/* types don't match? then force coersion using a function call... */
else if (input_typeids[i] != function_typeids[i])
{
lfirst(current_fargs) = coerce_type(pstate,
lfirst(current_fargs),
input_typeids[i],
function_typeids[i]);
}
}
}
/*
** setup_tlist
** Build a tlist that says which attribute to project to.
** This routine is called by ParseFuncOrColumn() to set up a target list
** on a tuple parameter or return value. Due to a bug in 4.0,
** it's not possible to refer to system attributes in this case.
*/
static List *
setup_tlist(char *attname, Oid relid)
{
TargetEntry *tle;
Resdom *resnode;
Var *varnode;
Oid typeid;
int32 type_mod;
int attno;
attno = get_attnum(relid, attname);
if (attno < 0)
elog(ERROR, "Cannot reference attribute '%s'"
" of tuple params/return values for functions", attname);
typeid = get_atttype(relid, attno);
type_mod = get_atttypmod(relid, attno);
resnode = makeResdom(1,
typeid,
type_mod,
get_attname(relid, attno),
0,
(Oid) 0,
0);
varnode = makeVar(-1, attno, typeid, type_mod, 0, -1, attno);
tle = makeTargetEntry(resnode, (Node *) varnode);
return lcons(tle, NIL);
}
/*
** setup_base_tlist
** Build a tlist that extracts a base type from the tuple
** returned by the executor.
*/
static List *
setup_base_tlist(Oid typeid)
{
TargetEntry *tle;
Resdom *resnode;
Var *varnode;
resnode = makeResdom(1,
typeid,
-1,
"<noname>",
0,
(Oid) 0,
0);
varnode = makeVar(-1, 1, typeid, -1, 0, -1, 1);
tle = makeTargetEntry(resnode, (Node *) varnode);
return lcons(tle, NIL);
}
/*
* ParseComplexProjection -
* handles function calls with a single argument that is of complex type.
* This routine returns NULL if it can't handle the projection (eg. sets).
*/
static Node *
ParseComplexProjection(ParseState *pstate,
char *funcname,
Node *first_arg,
bool *attisset)
{
Oid argtype;
Oid argrelid;
Relation rd;
Oid relid;
int attnum;
switch (nodeTag(first_arg))
{
case T_Iter:
{
Func *func;
Iter *iter;
iter = (Iter *) first_arg;
func = (Func *) ((Expr *) iter->iterexpr)->oper;
argtype = funcid_get_rettype(func->funcid);
argrelid = typeidTypeRelid(argtype);
if (argrelid &&
((attnum = get_attnum(argrelid, funcname))
!= InvalidAttrNumber))
{
/*
* the argument is a function returning a tuple, so
* funcname may be a projection
*/
/* add a tlist to the func node and return the Iter */
rd = heap_openr(typeidTypeName(argtype));
if (RelationIsValid(rd))
{
relid = RelationGetRelid(rd);
heap_close(rd);
}
if (RelationIsValid(rd))
{
func->func_tlist = setup_tlist(funcname, argrelid);
iter->itertype = attnumTypeId(rd, attnum);
return (Node *) iter;
}
else
{
elog(ERROR, "Function '%s' has bad return type %d",
funcname, argtype);
}
}
else
{
/* drop through */
;
}
break;
}
case T_Var:
{
/*
* The argument is a set, so this is either a projection
* or a function call on this set.
*/
*attisset = true;
break;
}
case T_Expr:
{
Expr *expr = (Expr *) first_arg;
Func *funcnode;
if (expr->opType != FUNC_EXPR)
break;
funcnode = (Func *) expr->oper;
argtype = funcid_get_rettype(funcnode->funcid);
argrelid = typeidTypeRelid(argtype);
/*
* the argument is a function returning a tuple, so
* funcname may be a projection
*/
if (argrelid &&
(attnum = get_attnum(argrelid, funcname))
!= InvalidAttrNumber)
{
/* add a tlist to the func node */
rd = heap_openr(typeidTypeName(argtype));
if (RelationIsValid(rd))
{
relid = RelationGetRelid(rd);
heap_close(rd);
}
if (RelationIsValid(rd))
{
Expr *newexpr;
funcnode->func_tlist = setup_tlist(funcname, argrelid);
funcnode->functype = attnumTypeId(rd, attnum);
newexpr = makeNode(Expr);
newexpr->typeOid = funcnode->functype;
newexpr->opType = FUNC_EXPR;
newexpr->oper = (Node *) funcnode;
newexpr->args = expr->args;
return (Node *) newexpr;
}
}
break;
}
case T_Param:
{
Param *param = (Param *) first_arg;
/*
* If the Param is a complex type, this could be a
* projection
*/
rd = heap_openr(typeidTypeName(param->paramtype));
if (RelationIsValid(rd))
{
relid = RelationGetRelid(rd);
heap_close(rd);
if ((attnum = get_attnum(relid, funcname))
!= InvalidAttrNumber)
{
param->paramtype = attnumTypeId(rd, attnum);
param->param_tlist = setup_tlist(funcname, relid);
return (Node *) param;
}
}
break;
}
default:
break;
}
return NULL;
}
/*
* Error message when function lookup fails that gives details of the
* argument types
*/
void
func_error(char *caller, char *funcname, int nargs, Oid *argtypes, char *msg)
{
char p[(NAMEDATALEN + 2) * MAXFMGRARGS],
*ptr;
int i;
ptr = p;
*ptr = '\0';
for (i = 0; i < nargs; i++)
{
if (i)
{
*ptr++ = ',';
*ptr++ = ' ';
}
if (argtypes[i] != 0)
{
strcpy(ptr, typeidTypeName(argtypes[i]));
*(ptr + NAMEDATALEN) = '\0';
}
else
strcpy(ptr, "opaque");
ptr += strlen(ptr);
}
if (caller == NULL)
{
elog(ERROR, "Function '%s(%s)' does not exist%s%s",
funcname, p, ((msg != NULL) ? "\n\t" : ""), ((msg != NULL) ? msg : ""));
}
else
{
elog(ERROR, "%s: function '%s(%s)' does not exist%s%s",
caller, funcname, p, ((msg != NULL) ? "\n\t" : ""), ((msg != NULL) ? msg : ""));
}
}
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