/*
* get_expr_result_type
* As above, but work from a calling expression node tree
*/
TypeFuncClass
get_expr_result_type(Node *expr,
Oid *resultTypeId,
TupleDesc *resultTupleDesc)
{
TypeFuncClass result;
if (expr && IsA(expr, FuncExpr))
result = internal_get_result_type(((FuncExpr *) expr)->funcid,
expr,
NULL,
resultTypeId,
resultTupleDesc);
else if (expr && IsA(expr, OpExpr))
result = internal_get_result_type(get_opcode(((OpExpr *) expr)->opno),
expr,
NULL,
resultTypeId,
resultTupleDesc);
else
{
/* handle as a generic expression; no chance to resolve RECORD */
Oid typid = exprType(expr);
if (resultTypeId)
*resultTypeId = typid;
if (resultTupleDesc)
*resultTupleDesc = NULL;
result = get_type_func_class(typid);
if (result == TYPEFUNC_COMPOSITE && resultTupleDesc)
*resultTupleDesc = lookup_rowtype_tupdesc_copy(typid, -1);
}
return result;
}
/*
* internal_get_result_type -- workhorse code implementing all the above
*
* funcid must always be supplied. call_expr and rsinfo can be NULL if not
* available. We will return TYPEFUNC_RECORD, and store NULL into
* *resultTupleDesc, if we cannot deduce the complete result rowtype from
* the available information.
*/
static TypeFuncClass
internal_get_result_type(Oid funcid,
Node *call_expr,
ReturnSetInfo *rsinfo,
Oid *resultTypeId,
TupleDesc *resultTupleDesc)
{
TypeFuncClass result;
HeapTuple tp;
Form_pg_proc procform;
Oid rettype;
TupleDesc tupdesc;
/* First fetch the function's pg_proc row to inspect its rettype */
tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
if (!HeapTupleIsValid(tp))
elog(ERROR, "cache lookup failed for function %u", funcid);
procform = (Form_pg_proc) GETSTRUCT(tp);
rettype = procform->prorettype;
/* Check for OUT parameters defining a RECORD result */
tupdesc = build_function_result_tupdesc_t(tp);
if (tupdesc)
{
/*
* It has OUT parameters, so it's basically like a regular composite
* type, except we have to be able to resolve any polymorphic OUT
* parameters.
*/
if (resultTypeId)
*resultTypeId = rettype;
if (resolve_polymorphic_tupdesc(tupdesc,
&procform->proargtypes,
call_expr))
{
if (tupdesc->tdtypeid == RECORDOID &&
tupdesc->tdtypmod < 0)
assign_record_type_typmod(tupdesc);
if (resultTupleDesc)
*resultTupleDesc = tupdesc;
result = TYPEFUNC_COMPOSITE;
}
else
{
if (resultTupleDesc)
*resultTupleDesc = NULL;
result = TYPEFUNC_RECORD;
}
ReleaseSysCache(tp);
return result;
}
/*
* If scalar polymorphic result, try to resolve it.
*/
if (IsPolymorphicType(rettype))
{
Oid newrettype = exprType(call_expr);
if (newrettype == InvalidOid) /* this probably should not happen */
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("could not determine actual result type for function \"%s\" declared to return type %s",
NameStr(procform->proname),
format_type_be(rettype))));
rettype = newrettype;
}
if (resultTypeId)
*resultTypeId = rettype;
if (resultTupleDesc)
*resultTupleDesc = NULL; /* default result */
/* Classify the result type */
result = get_type_func_class(rettype);
switch (result)
{
case TYPEFUNC_COMPOSITE:
if (resultTupleDesc)
*resultTupleDesc = lookup_rowtype_tupdesc_copy(rettype, -1);
/* Named composite types can't have any polymorphic columns */
break;
case TYPEFUNC_SCALAR:
break;
case TYPEFUNC_RECORD:
/* We must get the tupledesc from call context */
if (rsinfo && IsA(rsinfo, ReturnSetInfo) &&
rsinfo->expectedDesc != NULL)
{
result = TYPEFUNC_COMPOSITE;
if (resultTupleDesc)
*resultTupleDesc = rsinfo->expectedDesc;
/* Assume no polymorphic columns here, either */
}
break;
default:
break;
}
ReleaseSysCache(tp);
return result;
}
/*
* TypeGetTupleDesc
*
* Given a type Oid, build a TupleDesc. (In most cases you should be
* using get_call_result_type or one of its siblings instead of this
* routine, so that you can handle OUT parameters, RECORD result type,
* and polymorphic results.)
*
* If the type is composite, *and* a colaliases List is provided, *and*
* the List is of natts length, use the aliases instead of the relation
* attnames. (NB: this usage is deprecated since it may result in
* creation of unnecessary transient record types.)
*
* If the type is a base type, a single item alias List is required.
*/
TupleDesc
TypeGetTupleDesc(Oid typeoid, List *colaliases)
{
TypeFuncClass functypclass = get_type_func_class(typeoid);
TupleDesc tupdesc = NULL;
/*
* Build a suitable tupledesc representing the output rows
*/
if (functypclass == TYPEFUNC_COMPOSITE)
{
/* Composite data type, e.g. a table's row type */
tupdesc = lookup_rowtype_tupdesc_copy(typeoid, -1);
if (colaliases != NIL)
{
int natts = tupdesc->natts;
int varattno;
/* does the list length match the number of attributes? */
if (list_length(colaliases) != natts)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("number of aliases does not match number of columns")));
/* OK, use the aliases instead */
for (varattno = 0; varattno < natts; varattno++)
{
char *label = strVal(list_nth(colaliases, varattno));
if (label != NULL)
namestrcpy(&(tupdesc->attrs[varattno]->attname), label);
}
/* The tuple type is now an anonymous record type */
tupdesc->tdtypeid = RECORDOID;
tupdesc->tdtypmod = -1;
}
}
else if (functypclass == TYPEFUNC_SCALAR)
{
/* Base data type, i.e. scalar */
char *attname;
/* the alias list is required for base types */
if (colaliases == NIL)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("no column alias was provided")));
/* the alias list length must be 1 */
if (list_length(colaliases) != 1)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("number of aliases does not match number of columns")));
/* OK, get the column alias */
attname = strVal(linitial(colaliases));
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc,
(AttrNumber) 1,
attname,
typeoid,
-1,
0);
}
else if (functypclass == TYPEFUNC_RECORD)
{
/* XXX can't support this because typmod wasn't passed in ... */
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("could not determine row description for function returning record")));
}
else
{
/* crummy error message, but parser should have caught this */
elog(ERROR, "function in FROM has unsupported return type");
}
return tupdesc;
}
/*
* ExecMakeTableFunctionResult
*
* Evaluate a table function, producing a materialized result in a Tuplestore
* object.
*
* This is used by nodeFunctionscan.c.
*/
Tuplestorestate *
ExecMakeTableFunctionResult(SetExprState *setexpr,
ExprContext *econtext,
MemoryContext argContext,
TupleDesc expectedDesc,
bool randomAccess)
{
Tuplestorestate *tupstore = NULL;
TupleDesc tupdesc = NULL;
Oid funcrettype;
bool returnsTuple;
bool returnsSet = false;
FunctionCallInfoData fcinfo;
PgStat_FunctionCallUsage fcusage;
ReturnSetInfo rsinfo;
HeapTupleData tmptup;
MemoryContext callerContext;
MemoryContext oldcontext;
bool first_time = true;
callerContext = CurrentMemoryContext;
funcrettype = exprType((Node *) setexpr->expr);
returnsTuple = type_is_rowtype(funcrettype);
/*
* Prepare a resultinfo node for communication. We always do this even if
* not expecting a set result, so that we can pass expectedDesc. In the
* generic-expression case, the expression doesn't actually get to see the
* resultinfo, but set it up anyway because we use some of the fields as
* our own state variables.
*/
rsinfo.type = T_ReturnSetInfo;
rsinfo.econtext = econtext;
rsinfo.expectedDesc = expectedDesc;
rsinfo.allowedModes = (int) (SFRM_ValuePerCall | SFRM_Materialize | SFRM_Materialize_Preferred);
if (randomAccess)
rsinfo.allowedModes |= (int) SFRM_Materialize_Random;
rsinfo.returnMode = SFRM_ValuePerCall;
/* isDone is filled below */
rsinfo.setResult = NULL;
rsinfo.setDesc = NULL;
/*
* Normally the passed expression tree will be a SetExprState, since the
* grammar only allows a function call at the top level of a table
* function reference. However, if the function doesn't return set then
* the planner might have replaced the function call via constant-folding
* or inlining. So if we see any other kind of expression node, execute
* it via the general ExecEvalExpr() code; the only difference is that we
* don't get a chance to pass a special ReturnSetInfo to any functions
* buried in the expression.
*/
if (!setexpr->elidedFuncState)
{
/*
* This path is similar to ExecMakeFunctionResultSet.
*/
returnsSet = setexpr->funcReturnsSet;
InitFunctionCallInfoData(fcinfo, &(setexpr->func),
list_length(setexpr->args),
setexpr->fcinfo_data.fncollation,
NULL, (Node *) &rsinfo);
/*
* Evaluate the function's argument list.
*
* We can't do this in the per-tuple context: the argument values
* would disappear when we reset that context in the inner loop. And
* the caller's CurrentMemoryContext is typically a query-lifespan
* context, so we don't want to leak memory there. We require the
* caller to pass a separate memory context that can be used for this,
* and can be reset each time through to avoid bloat.
*/
MemoryContextReset(argContext);
oldcontext = MemoryContextSwitchTo(argContext);
ExecEvalFuncArgs(&fcinfo, setexpr->args, econtext);
MemoryContextSwitchTo(oldcontext);
/*
* If function is strict, and there are any NULL arguments, skip
* calling the function and act like it returned NULL (or an empty
* set, in the returns-set case).
*/
if (setexpr->func.fn_strict)
{
int i;
for (i = 0; i < fcinfo.nargs; i++)
{
if (fcinfo.argnull[i])
goto no_function_result;
}
}
}
else
{
/* Treat setexpr as a generic expression */
InitFunctionCallInfoData(fcinfo, NULL, 0, InvalidOid, NULL, NULL);
}
/*
* Switch to short-lived context for calling the function or expression.
*/
MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
/*
* Loop to handle the ValuePerCall protocol (which is also the same
* behavior needed in the generic ExecEvalExpr path).
*/
for (;;)
{
Datum result;
CHECK_FOR_INTERRUPTS();
/*
* reset per-tuple memory context before each call of the function or
* expression. This cleans up any local memory the function may leak
* when called.
*/
ResetExprContext(econtext);
/* Call the function or expression one time */
if (!setexpr->elidedFuncState)
{
pgstat_init_function_usage(&fcinfo, &fcusage);
fcinfo.isnull = false;
rsinfo.isDone = ExprSingleResult;
result = FunctionCallInvoke(&fcinfo);
pgstat_end_function_usage(&fcusage,
rsinfo.isDone != ExprMultipleResult);
}
else
{
result =
ExecEvalExpr(setexpr->elidedFuncState, econtext, &fcinfo.isnull);
rsinfo.isDone = ExprSingleResult;
}
/* Which protocol does function want to use? */
if (rsinfo.returnMode == SFRM_ValuePerCall)
{
/*
* Check for end of result set.
*/
if (rsinfo.isDone == ExprEndResult)
break;
/*
* If first time through, build tuplestore for result. For a
* scalar function result type, also make a suitable tupdesc.
*/
if (first_time)
{
oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
rsinfo.setResult = tupstore;
if (!returnsTuple)
{
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc,
(AttrNumber) 1,
"column",
funcrettype,
-1,
0);
rsinfo.setDesc = tupdesc;
}
MemoryContextSwitchTo(oldcontext);
}
/*
* Store current resultset item.
*/
if (returnsTuple)
{
if (!fcinfo.isnull)
{
HeapTupleHeader td = DatumGetHeapTupleHeader(result);
if (tupdesc == NULL)
{
/*
* This is the first non-NULL result from the
* function. Use the type info embedded in the
* rowtype Datum to look up the needed tupdesc. Make
* a copy for the query.
*/
oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
tupdesc = lookup_rowtype_tupdesc_copy(HeapTupleHeaderGetTypeId(td),
HeapTupleHeaderGetTypMod(td));
rsinfo.setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
}
else
{
/*
* Verify all later returned rows have same subtype;
* necessary in case the type is RECORD.
*/
if (HeapTupleHeaderGetTypeId(td) != tupdesc->tdtypeid ||
HeapTupleHeaderGetTypMod(td) != tupdesc->tdtypmod)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("rows returned by function are not all of the same row type")));
}
/*
* tuplestore_puttuple needs a HeapTuple not a bare
* HeapTupleHeader, but it doesn't need all the fields.
*/
tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
tmptup.t_data = td;
tuplestore_puttuple(tupstore, &tmptup);
}
else
{
/*
* NULL result from a tuple-returning function; expand it
* to a row of all nulls. We rely on the expectedDesc to
* form such rows. (Note: this would be problematic if
* tuplestore_putvalues saved the tdtypeid/tdtypmod from
* the provided descriptor, since that might not match
* what we get from the function itself. But it doesn't.)
*/
int natts = expectedDesc->natts;
bool *nullflags;
nullflags = (bool *) palloc(natts * sizeof(bool));
memset(nullflags, true, natts * sizeof(bool));
tuplestore_putvalues(tupstore, expectedDesc, NULL, nullflags);
}
}
else
{
/* Scalar-type case: just store the function result */
tuplestore_putvalues(tupstore, tupdesc, &result, &fcinfo.isnull);
}
/*
* Are we done?
*/
if (rsinfo.isDone != ExprMultipleResult)
break;
}
else if (rsinfo.returnMode == SFRM_Materialize)
{
/* check we're on the same page as the function author */
if (!first_time || rsinfo.isDone != ExprSingleResult)
ereport(ERROR,
(errcode(ERRCODE_E_R_I_E_SRF_PROTOCOL_VIOLATED),
errmsg("table-function protocol for materialize mode was not followed")));
/* Done evaluating the set result */
break;
}
else
ereport(ERROR,
(errcode(ERRCODE_E_R_I_E_SRF_PROTOCOL_VIOLATED),
errmsg("unrecognized table-function returnMode: %d",
(int) rsinfo.returnMode)));
first_time = false;
}
no_function_result:
/*
* If we got nothing from the function (ie, an empty-set or NULL result),
* we have to create the tuplestore to return, and if it's a
* non-set-returning function then insert a single all-nulls row. As
* above, we depend on the expectedDesc to manufacture the dummy row.
*/
if (rsinfo.setResult == NULL)
{
MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
rsinfo.setResult = tupstore;
if (!returnsSet)
{
int natts = expectedDesc->natts;
bool *nullflags;
MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
nullflags = (bool *) palloc(natts * sizeof(bool));
memset(nullflags, true, natts * sizeof(bool));
tuplestore_putvalues(tupstore, expectedDesc, NULL, nullflags);
}
}
/*
* If function provided a tupdesc, cross-check it. We only really need to
* do this for functions returning RECORD, but might as well do it always.
*/
if (rsinfo.setDesc)
{
tupledesc_match(expectedDesc, rsinfo.setDesc);
/*
* If it is a dynamically-allocated TupleDesc, free it: it is
* typically allocated in a per-query context, so we must avoid
* leaking it across multiple usages.
*/
if (rsinfo.setDesc->tdrefcount == -1)
FreeTupleDesc(rsinfo.setDesc);
}
MemoryContextSwitchTo(callerContext);
/* All done, pass back the tuplestore */
return rsinfo.setResult;
}
