/src/postgres/src/backend/utils/fmgr/funcapi.c

Source
/*-------------------------------------------------------------------------
 *
 * funcapi.c
 *    Utility and convenience functions for fmgr functions that return
 *    sets and/or composite types, or deal with VARIADIC inputs.
 *
 * Copyright (c) 2002-2026, PostgreSQL Global Development Group
 *
 * IDENTIFICATION
 *    src/backend/utils/fmgr/funcapi.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/htup_details.h"
#include "access/relation.h"
#include "catalog/namespace.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/regproc.h"
#include "utils/rel.h"
#include "utils/syscache.h"
#include "utils/tuplestore.h"
#include "utils/typcache.h"


typedef struct polymorphic_actuals
{
  Oid     anyelement_type;  /* anyelement mapping, if known */
  Oid     anyarray_type;  /* anyarray mapping, if known */
  Oid     anyrange_type;  /* anyrange mapping, if known */
  Oid     anymultirange_type; /* anymultirange mapping, if known */
} polymorphic_actuals;

static void shutdown_MultiFuncCall(Datum arg);
static TypeFuncClass internal_get_result_type(Oid funcid,
                        Node *call_expr,
                        ReturnSetInfo *rsinfo,
                        Oid *resultTypeId,
                        TupleDesc *resultTupleDesc);
static void resolve_anyelement_from_others(polymorphic_actuals *actuals);
static void resolve_anyarray_from_others(polymorphic_actuals *actuals);
static void resolve_anyrange_from_others(polymorphic_actuals *actuals);
static void resolve_anymultirange_from_others(polymorphic_actuals *actuals);
static bool resolve_polymorphic_tupdesc(TupleDesc tupdesc,
                    oidvector *declared_args,
                    Node *call_expr);
static TypeFuncClass get_type_func_class(Oid typid, Oid *base_typeid);


/*
 * InitMaterializedSRF
 *
 * Helper function to build the state of a set-returning function used
 * in the context of a single call with materialize mode.  This code
 * includes sanity checks on ReturnSetInfo, creates the Tuplestore and
 * the TupleDesc used with the function and stores them into the
 * function's ReturnSetInfo.
 *
 * "flags" can be set to MAT_SRF_USE_EXPECTED_DESC, to use the tuple
 * descriptor coming from expectedDesc, which is the tuple descriptor
 * expected by the caller.  MAT_SRF_BLESS can be set to complete the
 * information associated to the tuple descriptor, which is necessary
 * in some cases where the tuple descriptor comes from a transient
 * RECORD datatype.
 */
void
InitMaterializedSRF(FunctionCallInfo fcinfo, uint32 flags)
{
  bool    random_access;
  ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
  Tuplestorestate *tupstore;
  MemoryContext old_context,
        per_query_ctx;
  TupleDesc stored_tupdesc;

  /* check to see if caller supports returning a tuplestore */
  if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
    ereport(ERROR,
        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
         errmsg("set-valued function called in context that cannot accept a set")));
  if (!(rsinfo->allowedModes & SFRM_Materialize) ||
    ((flags & MAT_SRF_USE_EXPECTED_DESC) != 0 && rsinfo->expectedDesc == NULL))
    ereport(ERROR,
        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
         errmsg("materialize mode required, but it is not allowed in this context")));

  /*
   * Store the tuplestore and the tuple descriptor in ReturnSetInfo.  This
   * must be done in the per-query memory context.
   */
  per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
  old_context = MemoryContextSwitchTo(per_query_ctx);

  /* build a tuple descriptor for our result type */
  if ((flags & MAT_SRF_USE_EXPECTED_DESC) != 0)
    stored_tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc);
  else
  {
    if (get_call_result_type(fcinfo, NULL, &stored_tupdesc) != TYPEFUNC_COMPOSITE)
      elog(ERROR, "return type must be a row type");
  }

  /* If requested, bless the tuple descriptor */
  if ((flags & MAT_SRF_BLESS) != 0)
    BlessTupleDesc(stored_tupdesc);

  random_access = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;

  tupstore = tuplestore_begin_heap(random_access, false, work_mem);
  rsinfo->returnMode = SFRM_Materialize;
  rsinfo->setResult = tupstore;
  rsinfo->setDesc = stored_tupdesc;
  MemoryContextSwitchTo(old_context);
}


/*
 * init_MultiFuncCall
 * Create an empty FuncCallContext data structure
 * and do some other basic Multi-function call setup
 * and error checking
 */
FuncCallContext *
init_MultiFuncCall(PG_FUNCTION_ARGS)
{
  FuncCallContext *retval;

  /*
   * Bail if we're called in the wrong context
   */
  if (fcinfo->resultinfo == NULL || !IsA(fcinfo->resultinfo, ReturnSetInfo))
    ereport(ERROR,
        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
         errmsg("set-valued function called in context that cannot accept a set")));

  if (fcinfo->flinfo->fn_extra == NULL)
  {
    /*
     * First call
     */
    ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
    MemoryContext multi_call_ctx;

    /*
     * Create a suitably long-lived context to hold cross-call data
     */
    multi_call_ctx = AllocSetContextCreate(fcinfo->flinfo->fn_mcxt,
                         "SRF multi-call context",
                         ALLOCSET_SMALL_SIZES);

    /*
     * Allocate suitably long-lived space and zero it
     */
    retval = (FuncCallContext *)
      MemoryContextAllocZero(multi_call_ctx,
                   sizeof(FuncCallContext));

    /*
     * initialize the elements
     */
    retval->call_cntr = 0;
    retval->max_calls = 0;
    retval->user_fctx = NULL;
    retval->attinmeta = NULL;
    retval->tuple_desc = NULL;
    retval->multi_call_memory_ctx = multi_call_ctx;

    /*
     * save the pointer for cross-call use
     */
    fcinfo->flinfo->fn_extra = retval;

    /*
     * Ensure we will get shut down cleanly if the exprcontext is not run
     * to completion.
     */
    RegisterExprContextCallback(rsi->econtext,
                  shutdown_MultiFuncCall,
                  PointerGetDatum(fcinfo->flinfo));
  }
  else
  {
    /* second and subsequent calls */
    elog(ERROR, "init_MultiFuncCall cannot be called more than once");

    /* never reached, but keep compiler happy */
    retval = NULL;
  }

  return retval;
}

/*
 * per_MultiFuncCall
 *
 * Do Multi-function per-call setup
 */
FuncCallContext *
per_MultiFuncCall(PG_FUNCTION_ARGS)
{
  FuncCallContext *retval = (FuncCallContext *) fcinfo->flinfo->fn_extra;

  return retval;
}

/*
 * end_MultiFuncCall
 * Clean up after init_MultiFuncCall
 */
void
end_MultiFuncCall(PG_FUNCTION_ARGS, FuncCallContext *funcctx)
{
  ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;

  /* Deregister the shutdown callback */
  UnregisterExprContextCallback(rsi->econtext,
                  shutdown_MultiFuncCall,
                  PointerGetDatum(fcinfo->flinfo));

  /* But use it to do the real work */
  shutdown_MultiFuncCall(PointerGetDatum(fcinfo->flinfo));
}

/*
 * shutdown_MultiFuncCall
 * Shutdown function to clean up after init_MultiFuncCall
 */
static void
shutdown_MultiFuncCall(Datum arg)
{
  FmgrInfo   *flinfo = (FmgrInfo *) DatumGetPointer(arg);
  FuncCallContext *funcctx = (FuncCallContext *) flinfo->fn_extra;

  /* unbind from flinfo */
  flinfo->fn_extra = NULL;

  /*
   * Delete context that holds all multi-call data, including the
   * FuncCallContext itself
   */
  MemoryContextDelete(funcctx->multi_call_memory_ctx);
}


/*
 * get_call_result_type
 *    Given a function's call info record, determine the kind of datatype
 *    it is supposed to return.  If resultTypeId isn't NULL, *resultTypeId
 *    receives the actual datatype OID (this is mainly useful for scalar
 *    result types).  If resultTupleDesc isn't NULL, *resultTupleDesc
 *    receives a pointer to a TupleDesc when the result is of a composite
 *    type, or NULL when it's a scalar result.
 *
 * One hard case that this handles is resolution of actual rowtypes for
 * functions returning RECORD (from either the function's OUT parameter
 * list, or a ReturnSetInfo context node).  TYPEFUNC_RECORD is returned
 * only when we couldn't resolve the actual rowtype for lack of information.
 *
 * The other hard case that this handles is resolution of polymorphism.
 * We will never return polymorphic pseudotypes (ANYELEMENT etc), either
 * as a scalar result type or as a component of a rowtype.
 *
 * This function is relatively expensive --- in a function returning set,
 * try to call it only the first time through.
 */
TypeFuncClass
get_call_result_type(FunctionCallInfo fcinfo,
           Oid *resultTypeId,
           TupleDesc *resultTupleDesc)
{
  return internal_get_result_type(fcinfo->flinfo->fn_oid,
                  fcinfo->flinfo->fn_expr,
                  (ReturnSetInfo *) fcinfo->resultinfo,
                  resultTypeId,
                  resultTupleDesc);
}

/*
 * get_expr_result_type
 *    As above, but work from a calling expression node tree
 *
 * Beware of using this on the funcexpr of a RTE that has a coldeflist.
 * The correct conclusion in such cases is always that the function returns
 * RECORD with the columns defined by the coldeflist fields (funccolnames etc).
 * If it does not, it's the executor's responsibility to catch the discrepancy
 * at runtime; but code processing the query in advance of that point might
 * come to inconsistent conclusions if it checks the actual expression.
 */
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 if (expr && IsA(expr, RowExpr) &&
       ((RowExpr *) expr)->row_typeid == RECORDOID)
  {
    /* We can resolve the record type by generating the tupdesc directly */
    RowExpr    *rexpr = (RowExpr *) expr;
    TupleDesc tupdesc;
    AttrNumber  i = 1;
    ListCell   *lcc,
           *lcn;

    tupdesc = CreateTemplateTupleDesc(list_length(rexpr->args));
    Assert(list_length(rexpr->args) == list_length(rexpr->colnames));
    forboth(lcc, rexpr->args, lcn, rexpr->colnames)
    {
      Node     *col = (Node *) lfirst(lcc);
      char     *colname = strVal(lfirst(lcn));

      TupleDescInitEntry(tupdesc, i,
                 colname,
                 exprType(col),
                 exprTypmod(col),
                 0);
      TupleDescInitEntryCollation(tupdesc, i,
                    exprCollation(col));
      i++;
    }
    TupleDescFinalize(tupdesc);

    if (resultTypeId)
      *resultTypeId = rexpr->row_typeid;
    if (resultTupleDesc)
      *resultTupleDesc = BlessTupleDesc(tupdesc);
    return TYPEFUNC_COMPOSITE;
  }
  else if (expr && IsA(expr, Const) &&
       ((Const *) expr)->consttype == RECORDOID &&
       !((Const *) expr)->constisnull)
  {
    /*
     * When EXPLAIN'ing some queries with SEARCH/CYCLE clauses, we may
     * need to resolve field names of a RECORD-type Const.  The datum
     * should contain a typmod that will tell us that.
     */
    HeapTupleHeader rec;
    Oid     tupType;
    int32   tupTypmod;

    rec = DatumGetHeapTupleHeader(((Const *) expr)->constvalue);
    tupType = HeapTupleHeaderGetTypeId(rec);
    tupTypmod = HeapTupleHeaderGetTypMod(rec);
    if (resultTypeId)
      *resultTypeId = tupType;
    if (tupType != RECORDOID || tupTypmod >= 0)
    {
      /* Should be able to look it up */
      if (resultTupleDesc)
        *resultTupleDesc = lookup_rowtype_tupdesc_copy(tupType,
                                 tupTypmod);
      return TYPEFUNC_COMPOSITE;
    }
    else
    {
      /* This shouldn't really happen ... */
      if (resultTupleDesc)
        *resultTupleDesc = NULL;
      return TYPEFUNC_RECORD;
    }
  }
  else
  {
    /* handle as a generic expression; no chance to resolve RECORD */
    Oid     typid = exprType(expr);
    Oid     base_typid;

    if (resultTypeId)
      *resultTypeId = typid;
    if (resultTupleDesc)
      *resultTupleDesc = NULL;
    result = get_type_func_class(typid, &base_typid);
    if ((result == TYPEFUNC_COMPOSITE ||
       result == TYPEFUNC_COMPOSITE_DOMAIN) &&
      resultTupleDesc)
      *resultTupleDesc = lookup_rowtype_tupdesc_copy(base_typid, -1);
  }

  return result;
}

/*
 * get_func_result_type
 *    As above, but work from a function's OID only
 *
 * This will not be able to resolve pure-RECORD results nor polymorphism.
 */
TypeFuncClass
get_func_result_type(Oid functionId,
           Oid *resultTypeId,
           TupleDesc *resultTupleDesc)
{
  return internal_get_result_type(functionId,
                  NULL,
                  NULL,
                  resultTypeId,
                  resultTupleDesc);
}

/*
 * 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;
  Oid     base_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, &base_rettype);
  switch (result)
  {
    case TYPEFUNC_COMPOSITE:
    case TYPEFUNC_COMPOSITE_DOMAIN:
      if (resultTupleDesc)
        *resultTupleDesc = lookup_rowtype_tupdesc_copy(base_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;
}

/*
 * get_expr_result_tupdesc
 *    Get a tupdesc describing the result of a composite-valued expression
 *
 * If expression is not composite or rowtype can't be determined, returns NULL
 * if noError is true, else throws error.
 *
 * This is a simpler version of get_expr_result_type() for use when the caller
 * is only interested in determinate rowtype results.  As with that function,
 * beware of using this on the funcexpr of a RTE that has a coldeflist.
 */
TupleDesc
get_expr_result_tupdesc(Node *expr, bool noError)
{
  TupleDesc tupleDesc;
  TypeFuncClass functypclass;

  functypclass = get_expr_result_type(expr, NULL, &tupleDesc);

  if (functypclass == TYPEFUNC_COMPOSITE ||
    functypclass == TYPEFUNC_COMPOSITE_DOMAIN)
    return tupleDesc;

  if (!noError)
  {
    Oid     exprTypeId = exprType(expr);

    if (exprTypeId != RECORDOID)
      ereport(ERROR,
          (errcode(ERRCODE_WRONG_OBJECT_TYPE),
           errmsg("type %s is not composite",
              format_type_be(exprTypeId))));
    else
      ereport(ERROR,
          (errcode(ERRCODE_WRONG_OBJECT_TYPE),
           errmsg("record type has not been registered")));
  }

  return NULL;
}

/*
 * Resolve actual type of ANYELEMENT from other polymorphic inputs
 *
 * Note: the error cases here and in the sibling functions below are not
 * really user-facing; they could only occur if the function signature is
 * incorrect or the parser failed to enforce consistency of the actual
 * argument types.  Hence, we don't sweat too much over the error messages.
 */
static void
resolve_anyelement_from_others(polymorphic_actuals *actuals)
{
  if (OidIsValid(actuals->anyarray_type))
  {
    /* Use the element type corresponding to actual type */
    Oid     array_base_type = getBaseType(actuals->anyarray_type);
    Oid     array_typelem = get_element_type(array_base_type);

    if (!OidIsValid(array_typelem))
      ereport(ERROR,
          (errcode(ERRCODE_DATATYPE_MISMATCH),
           errmsg("argument declared %s is not an array but type %s",
              "anyarray",
              format_type_be(array_base_type))));
    actuals->anyelement_type = array_typelem;
  }
  else if (OidIsValid(actuals->anyrange_type))
  {
    /* Use the element type corresponding to actual type */
    Oid     range_base_type = getBaseType(actuals->anyrange_type);
    Oid     range_typelem = get_range_subtype(range_base_type);

    if (!OidIsValid(range_typelem))
      ereport(ERROR,
          (errcode(ERRCODE_DATATYPE_MISMATCH),
           errmsg("argument declared %s is not a range type but type %s",
              "anyrange",
              format_type_be(range_base_type))));
    actuals->anyelement_type = range_typelem;
  }
  else if (OidIsValid(actuals->anymultirange_type))
  {
    /* Use the element type based on the multirange type */
    Oid     multirange_base_type;
    Oid     multirange_typelem;
    Oid     range_base_type;
    Oid     range_typelem;

    multirange_base_type = getBaseType(actuals->anymultirange_type);
    multirange_typelem = get_multirange_range(multirange_base_type);
    if (!OidIsValid(multirange_typelem))
      ereport(ERROR,
          (errcode(ERRCODE_DATATYPE_MISMATCH),
           errmsg("argument declared %s is not a multirange type but type %s",
              "anymultirange",
              format_type_be(multirange_base_type))));

    range_base_type = getBaseType(multirange_typelem);
    range_typelem = get_range_subtype(range_base_type);

    if (!OidIsValid(range_typelem))
      ereport(ERROR,
          (errcode(ERRCODE_DATATYPE_MISMATCH),
           errmsg("argument declared %s does not contain a range type but type %s",
              "anymultirange",
              format_type_be(range_base_type))));
    actuals->anyelement_type = range_typelem;
  }
  else
    elog(ERROR, "could not determine polymorphic type");
}

/*
 * Resolve actual type of ANYARRAY from other polymorphic inputs
 */
static void
resolve_anyarray_from_others(polymorphic_actuals *actuals)
{
  /* If we don't know ANYELEMENT, resolve that first */
  if (!OidIsValid(actuals->anyelement_type))
    resolve_anyelement_from_others(actuals);

  if (OidIsValid(actuals->anyelement_type))
  {
    /* Use the array type corresponding to actual type */
    Oid     array_typeid = get_array_type(actuals->anyelement_type);

    if (!OidIsValid(array_typeid))
      ereport(ERROR,
          (errcode(ERRCODE_UNDEFINED_OBJECT),
           errmsg("could not find array type for data type %s",
              format_type_be(actuals->anyelement_type))));
    actuals->anyarray_type = array_typeid;
  }
  else
    elog(ERROR, "could not determine polymorphic type");
}

/*
 * Resolve actual type of ANYRANGE from other polymorphic inputs
 */
static void
resolve_anyrange_from_others(polymorphic_actuals *actuals)
{
  /*
   * We can't deduce a range type from other polymorphic array or base
   * types, because there may be multiple range types with the same subtype,
   * but we can deduce it from a polymorphic multirange type.
   */
  if (OidIsValid(actuals->anymultirange_type))
  {
    /* Use the element type based on the multirange type */
    Oid     multirange_base_type = getBaseType(actuals->anymultirange_type);
    Oid     multirange_typelem = get_multirange_range(multirange_base_type);

    if (!OidIsValid(multirange_typelem))
      ereport(ERROR,
          (errcode(ERRCODE_DATATYPE_MISMATCH),
           errmsg("argument declared %s is not a multirange type but type %s",
              "anymultirange",
              format_type_be(multirange_base_type))));
    actuals->anyrange_type = multirange_typelem;
  }
  else
    elog(ERROR, "could not determine polymorphic type");
}

/*
 * Resolve actual type of ANYMULTIRANGE from other polymorphic inputs
 */
static void
resolve_anymultirange_from_others(polymorphic_actuals *actuals)
{
  /*
   * We can't deduce a multirange type from polymorphic array or base types,
   * because there may be multiple range types with the same subtype, but we
   * can deduce it from a polymorphic range type.
   */
  if (OidIsValid(actuals->anyrange_type))
  {
    Oid     range_base_type = getBaseType(actuals->anyrange_type);
    Oid     multirange_typeid = get_range_multirange(range_base_type);

    if (!OidIsValid(multirange_typeid))
      ereport(ERROR,
          (errcode(ERRCODE_UNDEFINED_OBJECT),
           errmsg("could not find multirange type for data type %s",
              format_type_be(actuals->anyrange_type))));
    actuals->anymultirange_type = multirange_typeid;
  }
  else
    elog(ERROR, "could not determine polymorphic type");
}

/*
 * Given the result tuple descriptor for a function with OUT parameters,
 * replace any polymorphic column types (ANYELEMENT etc) in the tupdesc
 * with concrete data types deduced from the input arguments.
 * declared_args is an oidvector of the function's declared input arg types
 * (showing which are polymorphic), and call_expr is the call expression.
 *
 * Returns true if able to deduce all types, false if necessary information
 * is not provided (call_expr is NULL or arg types aren't identifiable).
 */
static bool
resolve_polymorphic_tupdesc(TupleDesc tupdesc, oidvector *declared_args,
              Node *call_expr)
{
  int     natts = tupdesc->natts;
  int     nargs = declared_args->dim1;
  bool    have_polymorphic_result = false;
  bool    have_anyelement_result = false;
  bool    have_anyarray_result = false;
  bool    have_anyrange_result = false;
  bool    have_anymultirange_result = false;
  bool    have_anycompatible_result = false;
  bool    have_anycompatible_array_result = false;
  bool    have_anycompatible_range_result = false;
  bool    have_anycompatible_multirange_result = false;
  polymorphic_actuals poly_actuals;
  polymorphic_actuals anyc_actuals;
  Oid     anycollation = InvalidOid;
  Oid     anycompatcollation = InvalidOid;
  int     i;

  /* See if there are any polymorphic outputs; quick out if not */
  for (i = 0; i < natts; i++)
  {
    switch (TupleDescAttr(tupdesc, i)->atttypid)
    {
      case ANYELEMENTOID:
      case ANYNONARRAYOID:
      case ANYENUMOID:
        have_polymorphic_result = true;
        have_anyelement_result = true;
        break;
      case ANYARRAYOID:
        have_polymorphic_result = true;
        have_anyarray_result = true;
        break;
      case ANYRANGEOID:
        have_polymorphic_result = true;
        have_anyrange_result = true;
        break;
      case ANYMULTIRANGEOID:
        have_polymorphic_result = true;
        have_anymultirange_result = true;
        break;
      case ANYCOMPATIBLEOID:
      case ANYCOMPATIBLENONARRAYOID:
        have_polymorphic_result = true;
        have_anycompatible_result = true;
        break;
      case ANYCOMPATIBLEARRAYOID:
        have_polymorphic_result = true;
        have_anycompatible_array_result = true;
        break;
      case ANYCOMPATIBLERANGEOID:
        have_polymorphic_result = true;
        have_anycompatible_range_result = true;
        break;
      case ANYCOMPATIBLEMULTIRANGEOID:
        have_polymorphic_result = true;
        have_anycompatible_multirange_result = true;
        break;
      default:
        break;
    }
  }
  if (!have_polymorphic_result)
    return true;

  /*
   * Otherwise, extract actual datatype(s) from input arguments.  (We assume
   * the parser already validated consistency of the arguments.  Also, for
   * the ANYCOMPATIBLE pseudotype family, we expect that all matching
   * arguments were coerced to the selected common supertype, so that it
   * doesn't matter which one's exposed type we look at.)
   */
  if (!call_expr)
    return false;     /* no hope */

  memset(&poly_actuals, 0, sizeof(poly_actuals));
  memset(&anyc_actuals, 0, sizeof(anyc_actuals));

  for (i = 0; i < nargs; i++)
  {
    switch (declared_args->values[i])
    {
      case ANYELEMENTOID:
      case ANYNONARRAYOID:
      case ANYENUMOID:
        if (!OidIsValid(poly_actuals.anyelement_type))
        {
          poly_actuals.anyelement_type =
            get_call_expr_argtype(call_expr, i);
          if (!OidIsValid(poly_actuals.anyelement_type))
            return false;
        }
        break;
      case ANYARRAYOID:
        if (!OidIsValid(poly_actuals.anyarray_type))
        {
          poly_actuals.anyarray_type =
            get_call_expr_argtype(call_expr, i);
          if (!OidIsValid(poly_actuals.anyarray_type))
            return false;
        }
        break;
      case ANYRANGEOID:
        if (!OidIsValid(poly_actuals.anyrange_type))
        {
          poly_actuals.anyrange_type =
            get_call_expr_argtype(call_expr, i);
          if (!OidIsValid(poly_actuals.anyrange_type))
            return false;
        }
        break;
      case ANYMULTIRANGEOID:
        if (!OidIsValid(poly_actuals.anymultirange_type))
        {
          poly_actuals.anymultirange_type =
            get_call_expr_argtype(call_expr, i);
          if (!OidIsValid(poly_actuals.anymultirange_type))
            return false;
        }
        break;
      case ANYCOMPATIBLEOID:
      case ANYCOMPATIBLENONARRAYOID:
        if (!OidIsValid(anyc_actuals.anyelement_type))
        {
          anyc_actuals.anyelement_type =
            get_call_expr_argtype(call_expr, i);
          if (!OidIsValid(anyc_actuals.anyelement_type))
            return false;
        }
        break;
      case ANYCOMPATIBLEARRAYOID:
        if (!OidIsValid(anyc_actuals.anyarray_type))
        {
          anyc_actuals.anyarray_type =
            get_call_expr_argtype(call_expr, i);
          if (!OidIsValid(anyc_actuals.anyarray_type))
            return false;
        }
        break;
      case ANYCOMPATIBLERANGEOID:
        if (!OidIsValid(anyc_actuals.anyrange_type))
        {
          anyc_actuals.anyrange_type =
            get_call_expr_argtype(call_expr, i);
          if (!OidIsValid(anyc_actuals.anyrange_type))
            return false;
        }
        break;
      case ANYCOMPATIBLEMULTIRANGEOID:
        if (!OidIsValid(anyc_actuals.anymultirange_type))
        {
          anyc_actuals.anymultirange_type =
            get_call_expr_argtype(call_expr, i);
          if (!OidIsValid(anyc_actuals.anymultirange_type))
            return false;
        }
        break;
      default:
        break;
    }
  }

  /* If needed, deduce one polymorphic type from others */
  if (have_anyelement_result && !OidIsValid(poly_actuals.anyelement_type))
    resolve_anyelement_from_others(&poly_actuals);

  if (have_anyarray_result && !OidIsValid(poly_actuals.anyarray_type))
    resolve_anyarray_from_others(&poly_actuals);

  if (have_anyrange_result && !OidIsValid(poly_actuals.anyrange_type))
    resolve_anyrange_from_others(&poly_actuals);

  if (have_anymultirange_result && !OidIsValid(poly_actuals.anymultirange_type))
    resolve_anymultirange_from_others(&poly_actuals);

  if (have_anycompatible_result && !OidIsValid(anyc_actuals.anyelement_type))
    resolve_anyelement_from_others(&anyc_actuals);

  if (have_anycompatible_array_result && !OidIsValid(anyc_actuals.anyarray_type))
    resolve_anyarray_from_others(&anyc_actuals);

  if (have_anycompatible_range_result && !OidIsValid(anyc_actuals.anyrange_type))
    resolve_anyrange_from_others(&anyc_actuals);

  if (have_anycompatible_multirange_result && !OidIsValid(anyc_actuals.anymultirange_type))
    resolve_anymultirange_from_others(&anyc_actuals);

  /*
   * Identify the collation to use for polymorphic OUT parameters. (It'll
   * necessarily be the same for both anyelement and anyarray, likewise for
   * anycompatible and anycompatiblearray.)  Note that range types are not
   * collatable, so any possible internal collation of a range type is not
   * considered here.
   */
  if (OidIsValid(poly_actuals.anyelement_type))
    anycollation = get_typcollation(poly_actuals.anyelement_type);
  else if (OidIsValid(poly_actuals.anyarray_type))
    anycollation = get_typcollation(poly_actuals.anyarray_type);

  if (OidIsValid(anyc_actuals.anyelement_type))
    anycompatcollation = get_typcollation(anyc_actuals.anyelement_type);
  else if (OidIsValid(anyc_actuals.anyarray_type))
    anycompatcollation = get_typcollation(anyc_actuals.anyarray_type);

  if (OidIsValid(anycollation) || OidIsValid(anycompatcollation))
  {
    /*
     * The types are collatable, so consider whether to use a nondefault
     * collation.  We do so if we can identify the input collation used
     * for the function.
     */
    Oid     inputcollation = exprInputCollation(call_expr);

    if (OidIsValid(inputcollation))
    {
      if (OidIsValid(anycollation))
        anycollation = inputcollation;
      if (OidIsValid(anycompatcollation))
        anycompatcollation = inputcollation;
    }
  }

  /* And finally replace the tuple column types as needed */
  for (i = 0; i < natts; i++)
  {
    Form_pg_attribute att = TupleDescAttr(tupdesc, i);

    switch (att->atttypid)
    {
      case ANYELEMENTOID:
      case ANYNONARRAYOID:
      case ANYENUMOID:
        TupleDescInitEntry(tupdesc, i + 1,
                   NameStr(att->attname),
                   poly_actuals.anyelement_type,
                   -1,
                   0);
        TupleDescInitEntryCollation(tupdesc, i + 1, anycollation);
        break;
      case ANYARRAYOID:
        TupleDescInitEntry(tupdesc, i + 1,
                   NameStr(att->attname),
                   poly_actuals.anyarray_type,
                   -1,
                   0);
        TupleDescInitEntryCollation(tupdesc, i + 1, anycollation);
        break;
      case ANYRANGEOID:
        TupleDescInitEntry(tupdesc, i + 1,
                   NameStr(att->attname),
                   poly_actuals.anyrange_type,
                   -1,
                   0);
        /* no collation should be attached to a range type */
        break;
      case ANYMULTIRANGEOID:
        TupleDescInitEntry(tupdesc, i + 1,
                   NameStr(att->attname),
                   poly_actuals.anymultirange_type,
                   -1,
                   0);
        /* no collation should be attached to a multirange type */
        break;
      case ANYCOMPATIBLEOID:
      case ANYCOMPATIBLENONARRAYOID:
        TupleDescInitEntry(tupdesc, i + 1,
                   NameStr(att->attname),
                   anyc_actuals.anyelement_type,
                   -1,
                   0);
        TupleDescInitEntryCollation(tupdesc, i + 1, anycompatcollation);
        break;
      case ANYCOMPATIBLEARRAYOID:
        TupleDescInitEntry(tupdesc, i + 1,
                   NameStr(att->attname),
                   anyc_actuals.anyarray_type,
                   -1,
                   0);
        TupleDescInitEntryCollation(tupdesc, i + 1, anycompatcollation);
        break;
      case ANYCOMPATIBLERANGEOID:
        TupleDescInitEntry(tupdesc, i + 1,
                   NameStr(att->attname),
                   anyc_actuals.anyrange_type,
                   -1,
                   0);
        /* no collation should be attached to a range type */
        break;
      case ANYCOMPATIBLEMULTIRANGEOID:
        TupleDescInitEntry(tupdesc, i + 1,
                   NameStr(att->attname),
                   anyc_actuals.anymultirange_type,
                   -1,
                   0);
        /* no collation should be attached to a multirange type */
        break;
      default:
        break;
    }
  }

  TupleDescFinalize(tupdesc);
  return true;
}

/*
 * Given the declared argument types and modes for a function, replace any
 * polymorphic types (ANYELEMENT etc) in argtypes[] with concrete data types
 * deduced from the input arguments found in call_expr.
 *
 * Returns true if able to deduce all types, false if necessary information
 * is not provided (call_expr is NULL or arg types aren't identifiable).
 *
 * This is the same logic as resolve_polymorphic_tupdesc, but with a different
 * argument representation, and slightly different output responsibilities.
 *
 * argmodes may be NULL, in which case all arguments are assumed to be IN mode.
 */
bool
resolve_polymorphic_argtypes(int numargs, Oid *argtypes, char *argmodes,
               Node *call_expr)
{
  bool    have_polymorphic_result = false;
  bool    have_anyelement_result = false;
  bool    have_anyarray_result = false;
  bool    have_anyrange_result = false;
  bool    have_anymultirange_result = false;
  bool    have_anycompatible_result = false;
  bool    have_anycompatible_array_result = false;
  bool    have_anycompatible_range_result = false;
  bool    have_anycompatible_multirange_result = false;
  polymorphic_actuals poly_actuals;
  polymorphic_actuals anyc_actuals;
  int     inargno;
  int     i;

  /*
   * First pass: resolve polymorphic inputs, check for outputs.  As in
   * resolve_polymorphic_tupdesc, we rely on the parser to have enforced
   * type consistency and coerced ANYCOMPATIBLE args to a common supertype.
   */
  memset(&poly_actuals, 0, sizeof(poly_actuals));
  memset(&anyc_actuals, 0, sizeof(anyc_actuals));
  inargno = 0;
  for (i = 0; i < numargs; i++)
  {
    char    argmode = argmodes ? argmodes[i] : PROARGMODE_IN;

    switch (argtypes[i])
    {
      case ANYELEMENTOID:
      case ANYNONARRAYOID:
      case ANYENUMOID:
        if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
        {
          have_polymorphic_result = true;
          have_anyelement_result = true;
        }
        else
        {
          if (!OidIsValid(poly_actuals.anyelement_type))
          {
            poly_actuals.anyelement_type =
              get_call_expr_argtype(call_expr, inargno);
            if (!OidIsValid(poly_actuals.anyelement_type))
              return false;
          }
          argtypes[i] = poly_actuals.anyelement_type;
        }
        break;
      case ANYARRAYOID:
        if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
        {
          have_polymorphic_result = true;
          have_anyarray_result = true;
        }
        else
        {
          if (!OidIsValid(poly_actuals.anyarray_type))
          {
            poly_actuals.anyarray_type =
              get_call_expr_argtype(call_expr, inargno);
            if (!OidIsValid(poly_actuals.anyarray_type))
              return false;
          }
          argtypes[i] = poly_actuals.anyarray_type;
        }
        break;
      case ANYRANGEOID:
        if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
        {
          have_polymorphic_result = true;
          have_anyrange_result = true;
        }
        else
        {
          if (!OidIsValid(poly_actuals.anyrange_type))
          {
            poly_actuals.anyrange_type =
              get_call_expr_argtype(call_expr, inargno);
            if (!OidIsValid(poly_actuals.anyrange_type))
              return false;
          }
          argtypes[i] = poly_actuals.anyrange_type;
        }
        break;
      case ANYMULTIRANGEOID:
        if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
        {
          have_polymorphic_result = true;
          have_anymultirange_result = true;
        }
        else
        {
          if (!OidIsValid(poly_actuals.anymultirange_type))
          {
            poly_actuals.anymultirange_type =
              get_call_expr_argtype(call_expr, inargno);
            if (!OidIsValid(poly_actuals.anymultirange_type))
              return false;
          }
          argtypes[i] = poly_actuals.anymultirange_type;
        }
        break;
      case ANYCOMPATIBLEOID:
      case ANYCOMPATIBLENONARRAYOID:
        if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
        {
          have_polymorphic_result = true;
          have_anycompatible_result = true;
        }
        else
        {
          if (!OidIsValid(anyc_actuals.anyelement_type))
          {
            anyc_actuals.anyelement_type =
              get_call_expr_argtype(call_expr, inargno);
            if (!OidIsValid(anyc_actuals.anyelement_type))
              return false;
          }
          argtypes[i] = anyc_actuals.anyelement_type;
        }
        break;
      case ANYCOMPATIBLEARRAYOID:
        if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
        {
          have_polymorphic_result = true;
          have_anycompatible_array_result = true;
        }
        else
        {
          if (!OidIsValid(anyc_actuals.anyarray_type))
          {
            anyc_actuals.anyarray_type =
              get_call_expr_argtype(call_expr, inargno);
            if (!OidIsValid(anyc_actuals.anyarray_type))
              return false;
          }
          argtypes[i] = anyc_actuals.anyarray_type;
        }
        break;
      case ANYCOMPATIBLERANGEOID:
        if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
        {
          have_polymorphic_result = true;
          have_anycompatible_range_result = true;
        }
        else
        {
          if (!OidIsValid(anyc_actuals.anyrange_type))
          {
            anyc_actuals.anyrange_type =
              get_call_expr_argtype(call_expr, inargno);
            if (!OidIsValid(anyc_actuals.anyrange_type))
              return false;
          }
          argtypes[i] = anyc_actuals.anyrange_type;
        }
        break;
      case ANYCOMPATIBLEMULTIRANGEOID:
        if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
        {
          have_polymorphic_result = true;
          have_anycompatible_multirange_result = true;
        }
        else
        {
          if (!OidIsValid(anyc_actuals.anymultirange_type))
          {
            anyc_actuals.anymultirange_type =
              get_call_expr_argtype(call_expr, inargno);
            if (!OidIsValid(anyc_actuals.anymultirange_type))
              return false;
          }
          argtypes[i] = anyc_actuals.anymultirange_type;
        }
        break;
      default:
        break;
    }
    if (argmode != PROARGMODE_OUT && argmode != PROARGMODE_TABLE)
      inargno++;
  }

  /* Done? */
  if (!have_polymorphic_result)
    return true;

  /* If needed, deduce one polymorphic type from others */
  if (have_anyelement_result && !OidIsValid(poly_actuals.anyelement_type))
    resolve_anyelement_from_others(&poly_actuals);

  if (have_anyarray_result && !OidIsValid(poly_actuals.anyarray_type))
    resolve_anyarray_from_others(&poly_actuals);

  if (have_anyrange_result && !OidIsValid(poly_actuals.anyrange_type))
    resolve_anyrange_from_others(&poly_actuals);

  if (have_anymultirange_result && !OidIsValid(poly_actuals.anymultirange_type))
    resolve_anymultirange_from_others(&poly_actuals);

  if (have_anycompatible_result && !OidIsValid(anyc_actuals.anyelement_type))
    resolve_anyelement_from_others(&anyc_actuals);

  if (have_anycompatible_array_result && !OidIsValid(anyc_actuals.anyarray_type))
    resolve_anyarray_from_others(&anyc_actuals);

  if (have_anycompatible_range_result && !OidIsValid(anyc_actuals.anyrange_type))
    resolve_anyrange_from_others(&anyc_actuals);

  if (have_anycompatible_multirange_result && !OidIsValid(anyc_actuals.anymultirange_type))
    resolve_anymultirange_from_others(&anyc_actuals);

  /* And finally replace the output column types as needed */
  for (i = 0; i < numargs; i++)
  {
    switch (argtypes[i])
    {
      case ANYELEMENTOID:
      case ANYNONARRAYOID:
      case ANYENUMOID:
        argtypes[i] = poly_actuals.anyelement_type;
        break;
      case ANYARRAYOID:
        argtypes[i] = poly_actuals.anyarray_type;
        break;
      case ANYRANGEOID:
        argtypes[i] = poly_actuals.anyrange_type;
        break;
      case ANYMULTIRANGEOID:
        argtypes[i] = poly_actuals.anymultirange_type;
        break;
      case ANYCOMPATIBLEOID:
      case ANYCOMPATIBLENONARRAYOID:
        argtypes[i] = anyc_actuals.anyelement_type;
        break;
      case ANYCOMPATIBLEARRAYOID:
        argtypes[i] = anyc_actuals.anyarray_type;
        break;
      case ANYCOMPATIBLERANGEOID:
        argtypes[i] = anyc_actuals.anyrange_type;
        break;
      case ANYCOMPATIBLEMULTIRANGEOID:
        argtypes[i] = anyc_actuals.anymultirange_type;
        break;
      default:
        break;
    }
  }

  return true;
}

/*
 * get_type_func_class
 *    Given the type OID, obtain its TYPEFUNC classification.
 *    Also, if it's a domain, return the base type OID.
 *
 * This is intended to centralize a bunch of formerly ad-hoc code for
 * classifying types.  The categories used here are useful for deciding
 * how to handle functions returning the datatype.
 */
static TypeFuncClass
get_type_func_class(Oid typid, Oid *base_typeid)
{
  *base_typeid = typid;

  switch (get_typtype(typid))
  {
    case TYPTYPE_COMPOSITE:
      return TYPEFUNC_COMPOSITE;
    case TYPTYPE_BASE:
    case TYPTYPE_ENUM:
    case TYPTYPE_RANGE:
    case TYPTYPE_MULTIRANGE:
      return TYPEFUNC_SCALAR;
    case TYPTYPE_DOMAIN:
      *base_typeid = typid = getBaseType(typid);
      if (get_typtype(typid) == TYPTYPE_COMPOSITE)
        return TYPEFUNC_COMPOSITE_DOMAIN;
      else        /* domain base type can't be a pseudotype */
        return TYPEFUNC_SCALAR;
    case TYPTYPE_PSEUDO:
      if (typid == RECORDOID)
        return TYPEFUNC_RECORD;

      /*
       * We treat VOID and CSTRING as legitimate scalar datatypes,
       * mostly for the convenience of the JDBC driver (which wants to
       * be able to do "SELECT * FROM foo()" for all legitimately
       * user-callable functions).
       */
      if (typid == VOIDOID || typid == CSTRINGOID)
        return TYPEFUNC_SCALAR;
      return TYPEFUNC_OTHER;
  }
  /* shouldn't get here, probably */
  return TYPEFUNC_OTHER;
}


/*
 * get_func_arg_info
 *
 * Fetch info about the argument types, names, and IN/OUT modes from the
 * pg_proc tuple.  Return value is the total number of arguments.
 * Other results are palloc'd.  *p_argtypes is always filled in, but
 * *p_argnames and *p_argmodes will be set NULL in the default cases
 * (no names, and all IN arguments, respectively).
 *
 * Note that this function simply fetches what is in the pg_proc tuple;
 * it doesn't do any interpretation of polymorphic types.
 */
int
get_func_arg_info(HeapTuple procTup,
          Oid **p_argtypes, char ***p_argnames, char **p_argmodes)
{
  Form_pg_proc procStruct = (Form_pg_proc) GETSTRUCT(procTup);
  Datum   proallargtypes;
  Datum   proargmodes;
  Datum   proargnames;
  bool    isNull;
  ArrayType  *arr;
  int     numargs;
  Datum    *elems;
  int     nelems;
  int     i;

  /* First discover the total number of parameters and get their types */
  proallargtypes = SysCacheGetAttr(PROCOID, procTup,
                   Anum_pg_proc_proallargtypes,
                   &isNull);
  if (!isNull)
  {
    /*
     * We expect the arrays to be 1-D arrays of the right types; verify
     * that.  For the OID and char arrays, we don't need to use
     * deconstruct_array() since the array data is just going to look like
     * a C array of values.
     */
    arr = DatumGetArrayTypeP(proallargtypes); /* ensure not toasted */
    numargs = ARR_DIMS(arr)[0];
    if (ARR_NDIM(arr) != 1 ||
      numargs < 0 ||
      ARR_HASNULL(arr) ||
      ARR_ELEMTYPE(arr) != OIDOID)
      elog(ERROR, "proallargtypes is not a 1-D Oid array or it contains nulls");
    Assert(numargs >= procStruct->pronargs);
    *p_argtypes = palloc_array(Oid, numargs);
    memcpy(*p_argtypes, ARR_DATA_PTR(arr),
         numargs * sizeof(Oid));
  }
  else
  {
    /* If no proallargtypes, use proargtypes */
    numargs = procStruct->proargtypes.dim1;
    Assert(numargs == procStruct->pronargs);
    *p_argtypes = palloc_array(Oid, numargs);
    memcpy(*p_argtypes, procStruct->proargtypes.values,
         numargs * sizeof(Oid));
  }

  /* Get argument names, if available */
  proargnames = SysCacheGetAttr(PROCOID, procTup,
                  Anum_pg_proc_proargnames,
                  &isNull);
  if (isNull)
    *p_argnames = NULL;
  else
  {
    deconstruct_array_builtin(DatumGetArrayTypeP(proargnames), TEXTOID,
                  &elems, NULL, &nelems);
    if (nelems != numargs) /* should not happen */
      elog(ERROR, "proargnames must have the same number of elements as the function has arguments");
    *p_argnames = palloc_array(char *, numargs);
    for (i = 0; i < numargs; i++)
      (*p_argnames)[i] = TextDatumGetCString(elems[i]);
  }

  /* Get argument modes, if available */
  proargmodes = SysCacheGetAttr(PROCOID, procTup,
                  Anum_pg_proc_proargmodes,
                  &isNull);
  if (isNull)
    *p_argmodes = NULL;
  else
  {
    arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
    if (ARR_NDIM(arr) != 1 ||
      ARR_DIMS(arr)[0] != numargs ||
      ARR_HASNULL(arr) ||
      ARR_ELEMTYPE(arr) != CHAROID)
      elog(ERROR, "proargmodes is not a 1-D char array of length %d or it contains nulls",
         numargs);
    *p_argmodes = (char *) palloc(numargs * sizeof(char));
    memcpy(*p_argmodes, ARR_DATA_PTR(arr),
         numargs * sizeof(char));
  }

  return numargs;
}

/*
 * get_func_trftypes
 *
 * Returns the number of transformed types used by the function.
 * If there are any, a palloc'd array of the type OIDs is returned
 * into *p_trftypes.
 */
int
get_func_trftypes(HeapTuple procTup,
          Oid **p_trftypes)
{
  Datum   protrftypes;
  ArrayType  *arr;
  int     nelems;
  bool    isNull;

  protrftypes = SysCacheGetAttr(PROCOID, procTup,
                  Anum_pg_proc_protrftypes,
                  &isNull);
  if (!isNull)
  {
    /*
     * We expect the arrays to be 1-D arrays of the right types; verify
     * that.  For the OID and char arrays, we don't need to use
     * deconstruct_array() since the array data is just going to look like
     * a C array of values.
     */
    arr = DatumGetArrayTypeP(protrftypes);  /* ensure not toasted */
    nelems = ARR_DIMS(arr)[0];
    if (ARR_NDIM(arr) != 1 ||
      nelems < 0 ||
      ARR_HASNULL(arr) ||
      ARR_ELEMTYPE(arr) != OIDOID)
      elog(ERROR, "protrftypes is not a 1-D Oid array or it contains nulls");
    *p_trftypes = palloc_array(Oid, nelems);
    memcpy(*p_trftypes, ARR_DATA_PTR(arr),
         nelems * sizeof(Oid));

    return nelems;
  }
  else
    return 0;
}

/*
 * get_func_input_arg_names
 *
 * Extract the names of input arguments only, given a function's
 * proargnames and proargmodes entries in Datum form.
 *
 * Returns the number of input arguments, which is the length of the
 * palloc'd array returned to *arg_names.  Entries for unnamed args
 * are set to NULL.  You don't get anything if proargnames is NULL.
 */
int
get_func_input_arg_names(Datum proargnames, Datum proargmodes,
             char ***arg_names)
{
  ArrayType  *arr;
  int     numargs;
  Datum    *argnames;
  char     *argmodes;
  char    **inargnames;
  int     numinargs;
  int     i;

  /* Do nothing if null proargnames */
  if (proargnames == PointerGetDatum(NULL))
  {
    *arg_names = NULL;
    return 0;
  }

  /*
   * We expect the arrays to be 1-D arrays of the right types; verify that.
   * For proargmodes, we don't need to use deconstruct_array() since the
   * array data is just going to look like a C array of values.
   */
  arr = DatumGetArrayTypeP(proargnames);  /* ensure not toasted */
  if (ARR_NDIM(arr) != 1 ||
    ARR_HASNULL(arr) ||
    ARR_ELEMTYPE(arr) != TEXTOID)
    elog(ERROR, "proargnames is not a 1-D text array or it contains nulls");
  deconstruct_array_builtin(arr, TEXTOID, &argnames, NULL, &numargs);
  if (proargmodes != PointerGetDatum(NULL))
  {
    arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
    if (ARR_NDIM(arr) != 1 ||
      ARR_DIMS(arr)[0] != numargs ||
      ARR_HASNULL(arr) ||
      ARR_ELEMTYPE(arr) != CHAROID)
      elog(ERROR, "proargmodes is not a 1-D char array of length %d or it contains nulls",
         numargs);
    argmodes = (char *) ARR_DATA_PTR(arr);
  }
  else
    argmodes = NULL;

  /* zero elements probably shouldn't happen, but handle it gracefully */
  if (numargs <= 0)
  {
    *arg_names = NULL;
    return 0;
  }

  /* extract input-argument names */
  inargnames = (char **) palloc(numargs * sizeof(char *));
  numinargs = 0;
  for (i = 0; i < numargs; i++)
  {
    if (argmodes == NULL ||
      argmodes[i] == PROARGMODE_IN ||
      argmodes[i] == PROARGMODE_INOUT ||
      argmodes[i] == PROARGMODE_VARIADIC)
    {
      char     *pname = TextDatumGetCString(argnames[i]);

      if (pname[0] != '\0')
        inargnames[numinargs] = pname;
      else
        inargnames[numinargs] = NULL;
      numinargs++;
    }
  }

  *arg_names = inargnames;
  return numinargs;
}


/*
 * get_func_result_name
 *
 * If the function has exactly one output parameter, and that parameter
 * is named, return the name (as a palloc'd string).  Else return NULL.
 *
 * This is used to determine the default output column name for functions
 * returning scalar types.
 */
char *
get_func_result_name(Oid functionId)
{
  char     *result;
  HeapTuple procTuple;
  Datum   proargmodes;
  Datum   proargnames;
  ArrayType  *arr;
  int     numargs;
  char     *argmodes;
  Datum    *argnames;
  int     numoutargs;
  int     nargnames;
  int     i;

  /* First fetch the function's pg_proc row */
  procTuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(functionId));
  if (!HeapTupleIsValid(procTuple))
    elog(ERROR, "cache lookup failed for function %u", functionId);

  /* If there are no named OUT parameters, return NULL */
  if (heap_attisnull(procTuple, Anum_pg_proc_proargmodes, NULL) ||
    heap_attisnull(procTuple, Anum_pg_proc_proargnames, NULL))
    result = NULL;
  else
  {
    /* Get the data out of the tuple */
    proargmodes = SysCacheGetAttrNotNull(PROCOID, procTuple,
                       Anum_pg_proc_proargmodes);
    proargnames = SysCacheGetAttrNotNull(PROCOID, procTuple,
                       Anum_pg_proc_proargnames);

    /*
     * We expect the arrays to be 1-D arrays of the right types; verify
     * that.  For the char array, we don't need to use deconstruct_array()
     * since the array data is just going to look like a C array of
     * values.
     */
    arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
    numargs = ARR_DIMS(arr)[0];
    if (ARR_NDIM(arr) != 1 ||
      numargs < 0 ||
      ARR_HASNULL(arr) ||
      ARR_ELEMTYPE(arr) != CHAROID)
      elog(ERROR, "proargmodes is not a 1-D char array or it contains nulls");
    argmodes = (char *) ARR_DATA_PTR(arr);
    arr = DatumGetArrayTypeP(proargnames);  /* ensure not toasted */
    if (ARR_NDIM(arr) != 1 ||
      ARR_DIMS(arr)[0] != numargs ||
      ARR_HASNULL(arr) ||
      ARR_ELEMTYPE(arr) != TEXTOID)
      elog(ERROR, "proargnames is not a 1-D text array of length %d or it contains nulls",
         numargs);
    deconstruct_array_builtin(arr, TEXTOID, &argnames, NULL, &nargnames);
    Assert(nargnames == numargs);

    /* scan for output argument(s) */
    result = NULL;
    numoutargs = 0;
    for (i = 0; i < numargs; i++)
    {
      if (argmodes[i] == PROARGMODE_IN ||
        argmodes[i] == PROARGMODE_VARIADIC)
        continue;
      Assert(argmodes[i] == PROARGMODE_OUT ||
           argmodes[i] == PROARGMODE_INOUT ||
           argmodes[i] == PROARGMODE_TABLE);
      if (++numoutargs > 1)
      {
        /* multiple out args, so forget it */
        result = NULL;
        break;
      }
      result = TextDatumGetCString(argnames[i]);
      if (result == NULL || result[0] == '\0')
      {
        /* Parameter is not named, so forget it */
        result = NULL;
        break;
      }
    }
  }

  ReleaseSysCache(procTuple);

  return result;
}


/*
 * build_function_result_tupdesc_t
 *
 * Given a pg_proc row for a function, return a tuple descriptor for the
 * result rowtype, or NULL if the function does not have OUT parameters.
 *
 * Note that this does not handle resolution of polymorphic types;
 * that is deliberate.
 */
TupleDesc
build_function_result_tupdesc_t(HeapTuple procTuple)
{
  Form_pg_proc procform = (Form_pg_proc) GETSTRUCT(procTuple);
  Datum   proallargtypes;
  Datum   proargmodes;
  Datum   proargnames;
  bool    isnull;

  /* Return NULL if the function isn't declared to return RECORD */
  if (procform->prorettype != RECORDOID)
    return NULL;

  /* If there are no OUT parameters, return NULL */
  if (heap_attisnull(procTuple, Anum_pg_proc_proallargtypes, NULL) ||
    heap_attisnull(procTuple, Anum_pg_proc_proargmodes, NULL))
    return NULL;

  /* Get the data out of the tuple */
  proallargtypes = SysCacheGetAttrNotNull(PROCOID, procTuple,
                      Anum_pg_proc_proallargtypes);
  proargmodes = SysCacheGetAttrNotNull(PROCOID, procTuple,
                     Anum_pg_proc_proargmodes);
  proargnames = SysCacheGetAttr(PROCOID, procTuple,
                  Anum_pg_proc_proargnames,
                  &isnull);
  if (isnull)
    proargnames = PointerGetDatum(NULL); /* just to be sure */

  return build_function_result_tupdesc_d(procform->prokind,
                       proallargtypes,
                       proargmodes,
                       proargnames);
}

/*
 * build_function_result_tupdesc_d
 *
 * Build a RECORD function's tupledesc from the pg_proc proallargtypes,
 * proargmodes, and proargnames arrays.  This is split out for the
 * convenience of ProcedureCreate, which needs to be able to compute the
 * tupledesc before actually creating the function.
 *
 * For functions (but not for procedures), returns NULL if there are not at
 * least two OUT or INOUT arguments.
 */
TupleDesc
build_function_result_tupdesc_d(char prokind,
                Datum proallargtypes,
                Datum proargmodes,
                Datum proargnames)
{
  TupleDesc desc;
  ArrayType  *arr;
  int     numargs;
  Oid      *argtypes;
  char     *argmodes;
  Datum    *argnames = NULL;
  Oid      *outargtypes;
  char    **outargnames;
  int     numoutargs;
  int     nargnames;
  int     i;

  /* Can't have output args if columns are null */
  if (proallargtypes == PointerGetDatum(NULL) ||
    proargmodes == PointerGetDatum(NULL))
    return NULL;

  /*
   * We expect the arrays to be 1-D arrays of the right types; verify that.
   * For the OID and char arrays, we don't need to use deconstruct_array()
   * since the array data is just going to look like a C array of values.
   */
  arr = DatumGetArrayTypeP(proallargtypes); /* ensure not toasted */
  numargs = ARR_DIMS(arr)[0];
  if (ARR_NDIM(arr) != 1 ||
    numargs < 0 ||
    ARR_HASNULL(arr) ||
    ARR_ELEMTYPE(arr) != OIDOID)
    elog(ERROR, "proallargtypes is not a 1-D Oid array or it contains nulls");
  argtypes = (Oid *) ARR_DATA_PTR(arr);
  arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
  if (ARR_NDIM(arr) != 1 ||
    ARR_DIMS(arr)[0] != numargs ||
    ARR_HASNULL(arr) ||
    ARR_ELEMTYPE(arr) != CHAROID)
    elog(ERROR, "proargmodes is not a 1-D char array of length %d or it contains nulls",
       numargs);
  argmodes = (char *) ARR_DATA_PTR(arr);
  if (proargnames != PointerGetDatum(NULL))
  {
    arr = DatumGetArrayTypeP(proargnames);  /* ensure not toasted */
    if (ARR_NDIM(arr) != 1 ||
      ARR_DIMS(arr)[0] != numargs ||
      ARR_HASNULL(arr) ||
      ARR_ELEMTYPE(arr) != TEXTOID)
      elog(ERROR, "proargnames is not a 1-D text array of length %d or it contains nulls",
         numargs);
    deconstruct_array_builtin(arr, TEXTOID, &argnames, NULL, &nargnames);
    Assert(nargnames == numargs);
  }

  /* zero elements probably shouldn't happen, but handle it gracefully */
  if (numargs <= 0)
    return NULL;

  /* extract output-argument types and names */
  outargtypes = (Oid *) palloc(numargs * sizeof(Oid));
  outargnames = (char **) palloc(numargs * sizeof(char *));
  numoutargs = 0;
  for (i = 0; i < numargs; i++)
  {
    char     *pname;

    if (argmodes[i] == PROARGMODE_IN ||
      argmodes[i] == PROARGMODE_VARIADIC)
      continue;
    Assert(argmodes[i] == PROARGMODE_OUT ||
         argmodes[i] == PROARGMODE_INOUT ||
         argmodes[i] == PROARGMODE_TABLE);
    outargtypes[numoutargs] = argtypes[i];
    if (argnames)
      pname = TextDatumGetCString(argnames[i]);
    else
      pname = NULL;
    if (pname == NULL || pname[0] == '\0')
    {
      /* Parameter is not named, so gin up a column name */
      pname = psprintf("column%d", numoutargs + 1);
    }
    outargnames[numoutargs] = pname;
    numoutargs++;
  }

  /*
   * If there is no output argument, or only one, the function does not
   * return tuples.
   */
  if (numoutargs < 2 && prokind != PROKIND_PROCEDURE)
    return NULL;

  desc = CreateTemplateTupleDesc(numoutargs);
  for (i = 0; i < numoutargs; i++)
  {
    TupleDescInitEntry(desc, i + 1,
               outargnames[i],
               outargtypes[i],
               -1,
               0);
  }

  TupleDescFinalize(desc);

  return desc;
}


/*
 * RelationNameGetTupleDesc
 *
 * Given a (possibly qualified) relation name, build a TupleDesc.
 *
 * Note: while this works as advertised, it's seldom the best way to
 * build a tupdesc for a function's result type.  It's kept around
 * only for backwards compatibility with existing user-written code.
 */
TupleDesc
RelationNameGetTupleDesc(const char *relname)
{
  RangeVar   *relvar;
  Relation  rel;
  TupleDesc tupdesc;
  List     *relname_list;

  /* Open relation and copy the tuple description */
  relname_list = stringToQualifiedNameList(relname, NULL);
  relvar = makeRangeVarFromNameList(relname_list);
  rel = relation_openrv(relvar, AccessShareLock);
  tupdesc = CreateTupleDescCopy(RelationGetDescr(rel));
  relation_close(rel, AccessShareLock);

  return tupdesc;
}

/*
 * 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)
{
  Oid     base_typeoid;
  TypeFuncClass functypclass = get_type_func_class(typeoid, &base_typeoid);
  TupleDesc tupdesc = NULL;

  /*
   * Build a suitable tupledesc representing the output rows.  We
   * intentionally do not support TYPEFUNC_COMPOSITE_DOMAIN here, as it's
   * unlikely that legacy callers of this obsolete function would be
   * prepared to apply domain constraints.
   */
  if (functypclass == TYPEFUNC_COMPOSITE)
  {
    /* Composite data type, e.g. a table's row type */
    tupdesc = lookup_rowtype_tupdesc_copy(base_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));
        Form_pg_attribute attr = TupleDescAttr(tupdesc, varattno);

        if (label != NULL)
          namestrcpy(&(attr->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);
    TupleDescInitEntry(tupdesc,
               (AttrNumber) 1,
               attname,
               typeoid,
               -1,
               0);
    TupleDescFinalize(tupdesc);
  }
  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;
}

/*
 * extract_variadic_args
 *
 * Extract a set of argument values, types and NULL markers for a given
 * input function which makes use of a VARIADIC input whose argument list
 * depends on the caller context. When doing a VARIADIC call, the caller
 * has provided one argument made of an array of values, so deconstruct the
 * array data before using it for the next processing. If no VARIADIC call
 * is used, just fill in the status data based on all the arguments given
 * by the caller.
 *
 * This function returns the number of arguments generated, or -1 in the
 * case of "VARIADIC NULL".
 */
int
extract_variadic_args(FunctionCallInfo fcinfo, int variadic_start,
            bool convert_unknown, Datum **args, Oid **types,
            bool **nulls)
{
  bool    variadic = get_fn_expr_variadic(fcinfo->flinfo);
  Datum    *args_res;
  bool     *nulls_res;
  Oid      *types_res;
  int     nargs,
        i;

  *args = NULL;
  *types = NULL;
  *nulls = NULL;

  if (variadic)
  {
    ArrayType  *array_in;
    Oid     element_type;
    bool    typbyval;
    char    typalign;
    int16   typlen;

    Assert(PG_NARGS() == variadic_start + 1);

    if (PG_ARGISNULL(variadic_start))
      return -1;

    array_in = PG_GETARG_ARRAYTYPE_P(variadic_start);
    element_type = ARR_ELEMTYPE(array_in);

    get_typlenbyvalalign(element_type,
               &typlen, &typbyval, &typalign);
    deconstruct_array(array_in, element_type, typlen, typbyval,
              typalign, &args_res, &nulls_res,
              &nargs);

    /* All the elements of the array have the same type */
    types_res = (Oid *) palloc0(nargs * sizeof(Oid));
    for (i = 0; i < nargs; i++)
      types_res[i] = element_type;
  }
  else
  {
    nargs = PG_NARGS() - variadic_start;
    Assert(nargs > 0);
    nulls_res = (bool *) palloc0(nargs * sizeof(bool));
    args_res = (Datum *) palloc0(nargs * sizeof(Datum));
    types_res = (Oid *) palloc0(nargs * sizeof(Oid));

    for (i = 0; i < nargs; i++)
    {
      nulls_res[i] = PG_ARGISNULL(i + variadic_start);
      types_res[i] = get_fn_expr_argtype(fcinfo->flinfo,
                         i + variadic_start);

      /*
       * Turn a constant (more or less literal) value that's of unknown
       * type into text if required. Unknowns come in as a cstring
       * pointer. Note: for functions declared as taking type "any", the
       * parser will not do any type conversion on unknown-type literals
       * (that is, undecorated strings or NULLs).
       */
      if (convert_unknown &&
        types_res[i] == UNKNOWNOID &&
        get_fn_expr_arg_stable(fcinfo->flinfo, i + variadic_start))
      {
        types_res[i] = TEXTOID;

        if (PG_ARGISNULL(i + variadic_start))
          args_res[i] = (Datum) 0;
        else
          args_res[i] =
            CStringGetTextDatum(PG_GETARG_POINTER(i + variadic_start));
      }
      else
      {
        /* no conversion needed, just take the datum as given */
        args_res[i] = PG_GETARG_DATUM(i + variadic_start);
      }

      if (!OidIsValid(types_res[i]) ||
        (convert_unknown && types_res[i] == UNKNOWNOID))
        ereport(ERROR,
            (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
             errmsg("could not determine data type for argument %d",
                i + 1)));
    }
  }

  /* Fill in results */
  *args = args_res;
  *nulls = nulls_res;
  *types = types_res;

  return nargs;
}

Coverage Report

Created: 2026-11-12 07:20