Adding upstream version 16.2.upstream/16.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 360 insertions, 0 deletions

diff --git a/src/include/funcapi.h b/src/include/funcapi.h
new file mode 100644
index 0000000..cc0cca3
--- /dev/null
+++ b/src/include/funcapi.h
@@ -0,0 +1,360 @@
+/*-------------------------------------------------------------------------
+ *
+ * funcapi.h
+ *	  Definitions for functions which return composite type and/or sets
+ *	  or work on VARIADIC inputs.
+ *
+ * This file must be included by all Postgres modules that either define
+ * or call FUNCAPI-callable functions or macros.
+ *
+ *
+ * Copyright (c) 2002-2023, PostgreSQL Global Development Group
+ *
+ * src/include/funcapi.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef FUNCAPI_H
+#define FUNCAPI_H
+
+#include "access/tupdesc.h"
+#include "executor/executor.h"
+#include "executor/tuptable.h"
+#include "fmgr.h"
+
+/*-------------------------------------------------------------------------
+ *	Support to ease writing Functions returning composite types
+ *-------------------------------------------------------------------------
+ *
+ * This struct holds arrays of individual attribute information
+ * needed to create a tuple from raw C strings. It also requires
+ * a copy of the TupleDesc. The information carried here
+ * is derived from the TupleDesc, but it is stored here to
+ * avoid redundant cpu cycles on each call to an SRF.
+ */
+typedef struct AttInMetadata
+{
+	/* full TupleDesc */
+	TupleDesc	tupdesc;
+
+	/* array of attribute type input function finfo */
+	FmgrInfo   *attinfuncs;
+
+	/* array of attribute type i/o parameter OIDs */
+	Oid		   *attioparams;
+
+	/* array of attribute typmod */
+	int32	   *atttypmods;
+} AttInMetadata;
+
+/*-------------------------------------------------------------------------
+ *		Support struct to ease writing Set Returning Functions (SRFs)
+ *-------------------------------------------------------------------------
+ *
+ * This struct holds function context for Set Returning Functions.
+ * Use fn_extra to hold a pointer to it across calls
+ */
+typedef struct FuncCallContext
+{
+	/*
+	 * Number of times we've been called before
+	 *
+	 * call_cntr is initialized to 0 for you by SRF_FIRSTCALL_INIT(), and
+	 * incremented for you every time SRF_RETURN_NEXT() is called.
+	 */
+	uint64		call_cntr;
+
+	/*
+	 * OPTIONAL maximum number of calls
+	 *
+	 * max_calls is here for convenience only and setting it is optional. If
+	 * not set, you must provide alternative means to know when the function
+	 * is done.
+	 */
+	uint64		max_calls;
+
+	/*
+	 * OPTIONAL pointer to miscellaneous user-provided context information
+	 *
+	 * user_fctx is for use as a pointer to your own struct to retain
+	 * arbitrary context information between calls of your function.
+	 */
+	void	   *user_fctx;
+
+	/*
+	 * OPTIONAL pointer to struct containing attribute type input metadata
+	 *
+	 * attinmeta is for use when returning tuples (i.e. composite data types)
+	 * and is not used when returning base data types. It is only needed if
+	 * you intend to use BuildTupleFromCStrings() to create the return tuple.
+	 */
+	AttInMetadata *attinmeta;
+
+	/*
+	 * memory context used for structures that must live for multiple calls
+	 *
+	 * multi_call_memory_ctx is set by SRF_FIRSTCALL_INIT() for you, and used
+	 * by SRF_RETURN_DONE() for cleanup. It is the most appropriate memory
+	 * context for any memory that is to be reused across multiple calls of
+	 * the SRF.
+	 */
+	MemoryContext multi_call_memory_ctx;
+
+	/*
+	 * OPTIONAL pointer to struct containing tuple description
+	 *
+	 * tuple_desc is for use when returning tuples (i.e. composite data types)
+	 * and is only needed if you are going to build the tuples with
+	 * heap_form_tuple() rather than with BuildTupleFromCStrings(). Note that
+	 * the TupleDesc pointer stored here should usually have been run through
+	 * BlessTupleDesc() first.
+	 */
+	TupleDesc	tuple_desc;
+
+} FuncCallContext;
+
+/*----------
+ *	Support to ease writing functions returning composite types
+ *
+ * External declarations:
+ * 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 or the rowtype could not be
+ *		determined.  NB: the tupledesc should be copied if it is to be
+ *		accessed over a long period.
+ * get_expr_result_type:
+ *		Given an expression node, return the same info as for
+ *		get_call_result_type.  Note: the cases in which rowtypes cannot be
+ *		determined are different from the cases for get_call_result_type.
+ * get_func_result_type:
+ *		Given only a function's OID, return the same info as for
+ *		get_call_result_type.  Note: the cases in which rowtypes cannot be
+ *		determined are different from the cases for get_call_result_type.
+ *		Do *not* use this if you can use one of the others.
+ *
+ * See also get_expr_result_tupdesc(), which is a convenient wrapper around
+ * get_expr_result_type() for use when the caller only cares about
+ * determinable-rowtype cases.
+ *----------
+ */
+
+/* Type categories for get_call_result_type and siblings */
+typedef enum TypeFuncClass
+{
+	TYPEFUNC_SCALAR,			/* scalar result type */
+	TYPEFUNC_COMPOSITE,			/* determinable rowtype result */
+	TYPEFUNC_COMPOSITE_DOMAIN,	/* domain over determinable rowtype result */
+	TYPEFUNC_RECORD,			/* indeterminate rowtype result */
+	TYPEFUNC_OTHER				/* bogus type, eg pseudotype */
+} TypeFuncClass;
+
+extern TypeFuncClass get_call_result_type(FunctionCallInfo fcinfo,
+										  Oid *resultTypeId,
+										  TupleDesc *resultTupleDesc);
+extern TypeFuncClass get_expr_result_type(Node *expr,
+										  Oid *resultTypeId,
+										  TupleDesc *resultTupleDesc);
+extern TypeFuncClass get_func_result_type(Oid functionId,
+										  Oid *resultTypeId,
+										  TupleDesc *resultTupleDesc);
+
+extern TupleDesc get_expr_result_tupdesc(Node *expr, bool noError);
+
+extern bool resolve_polymorphic_argtypes(int numargs, Oid *argtypes,
+										 char *argmodes,
+										 Node *call_expr);
+
+extern int	get_func_arg_info(HeapTuple procTup,
+							  Oid **p_argtypes, char ***p_argnames,
+							  char **p_argmodes);
+
+extern int	get_func_input_arg_names(Datum proargnames, Datum proargmodes,
+									 char ***arg_names);
+
+extern int	get_func_trftypes(HeapTuple procTup, Oid **p_trftypes);
+extern char *get_func_result_name(Oid functionId);
+
+extern TupleDesc build_function_result_tupdesc_d(char prokind,
+												 Datum proallargtypes,
+												 Datum proargmodes,
+												 Datum proargnames);
+extern TupleDesc build_function_result_tupdesc_t(HeapTuple procTuple);
+
+
+/*----------
+ *	Support to ease writing functions returning composite types
+ *
+ * External declarations:
+ * TupleDesc BlessTupleDesc(TupleDesc tupdesc) - "Bless" a completed tuple
+ *		descriptor so that it can be used to return properly labeled tuples.
+ *		You need to call this if you are going to use heap_form_tuple directly.
+ *		TupleDescGetAttInMetadata does it for you, however, so no need to call
+ *		it if you call TupleDescGetAttInMetadata.
+ * AttInMetadata *TupleDescGetAttInMetadata(TupleDesc tupdesc) - Build an
+ *		AttInMetadata struct based on the given TupleDesc. AttInMetadata can
+ *		be used in conjunction with C strings to produce a properly formed
+ *		tuple.
+ * HeapTuple BuildTupleFromCStrings(AttInMetadata *attinmeta, char **values) -
+ *		build a HeapTuple given user data in C string form. values is an array
+ *		of C strings, one for each attribute of the return tuple.
+ * Datum HeapTupleHeaderGetDatum(HeapTupleHeader tuple) - convert a
+ *		HeapTupleHeader to a Datum.
+ *
+ * Inline declarations:
+ * HeapTupleGetDatum(HeapTuple tuple) - convert a HeapTuple to a Datum.
+ *
+ * Obsolete routines and macros:
+ * TupleDesc RelationNameGetTupleDesc(const char *relname) - Use to get a
+ *		TupleDesc based on a named relation.
+ * TupleDesc TypeGetTupleDesc(Oid typeoid, List *colaliases) - Use to get a
+ *		TupleDesc based on a type OID.
+ * TupleGetDatum(TupleTableSlot *slot, HeapTuple tuple) - get a Datum
+ *		given a tuple and a slot.
+ *----------
+ */
+
+extern TupleDesc RelationNameGetTupleDesc(const char *relname);
+extern TupleDesc TypeGetTupleDesc(Oid typeoid, List *colaliases);
+
+/* from execTuples.c */
+extern TupleDesc BlessTupleDesc(TupleDesc tupdesc);
+extern AttInMetadata *TupleDescGetAttInMetadata(TupleDesc tupdesc);
+extern HeapTuple BuildTupleFromCStrings(AttInMetadata *attinmeta, char **values);
+extern Datum HeapTupleHeaderGetDatum(HeapTupleHeader tuple);
+
+static inline Datum
+HeapTupleGetDatum(const HeapTupleData *tuple)
+{
+	return HeapTupleHeaderGetDatum(tuple->t_data);
+}
+
+/* obsolete version of above */
+#define TupleGetDatum(_slot, _tuple)	HeapTupleGetDatum(_tuple)
+
+
+/*----------
+ *		Support for Set Returning Functions (SRFs)
+ *
+ * The basic API for SRFs using ValuePerCall mode looks something like this:
+ *
+ * Datum
+ * my_Set_Returning_Function(PG_FUNCTION_ARGS)
+ * {
+ *	FuncCallContext    *funcctx;
+ *	Datum				result;
+ *	MemoryContext		oldcontext;
+ *	<user defined declarations>
+ *
+ *	if (SRF_IS_FIRSTCALL())
+ *	{
+ *		funcctx = SRF_FIRSTCALL_INIT();
+ *		// switch context when allocating stuff to be used in later calls
+ *		oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+ *		<user defined code>
+ *		<if returning composite>
+ *			<build TupleDesc, and perhaps AttInMetadata>
+ *		<endif returning composite>
+ *		<user defined code>
+ *		// return to original context when allocating transient memory
+ *		MemoryContextSwitchTo(oldcontext);
+ *	}
+ *	<user defined code>
+ *	funcctx = SRF_PERCALL_SETUP();
+ *	<user defined code>
+ *
+ *	if (funcctx->call_cntr < funcctx->max_calls)
+ *	{
+ *		<user defined code>
+ *		<obtain result Datum>
+ *		SRF_RETURN_NEXT(funcctx, result);
+ *	}
+ *	else
+ *		SRF_RETURN_DONE(funcctx);
+ * }
+ *
+ * NOTE: there is no guarantee that a SRF using ValuePerCall mode will be
+ * run to completion; for example, a query with LIMIT might stop short of
+ * fetching all the rows.  Therefore, do not expect that you can do resource
+ * cleanup just before SRF_RETURN_DONE().  You need not worry about releasing
+ * memory allocated in multi_call_memory_ctx, but holding file descriptors or
+ * other non-memory resources open across calls is a bug.  SRFs that need
+ * such resources should not use these macros, but instead populate a
+ * tuplestore during a single call, as set up by InitMaterializedSRF() (see
+ * fmgr/README).  Alternatively, set up a callback to release resources
+ * at query shutdown, using RegisterExprContextCallback().
+ *
+ *----------
+ */
+
+/* from funcapi.c */
+
+/* flag bits for InitMaterializedSRF() */
+#define MAT_SRF_USE_EXPECTED_DESC	0x01	/* use expectedDesc as tupdesc. */
+#define MAT_SRF_BLESS				0x02	/* "Bless" a tuple descriptor with
+											 * BlessTupleDesc(). */
+extern void InitMaterializedSRF(FunctionCallInfo fcinfo, bits32 flags);
+
+extern FuncCallContext *init_MultiFuncCall(PG_FUNCTION_ARGS);
+extern FuncCallContext *per_MultiFuncCall(PG_FUNCTION_ARGS);
+extern void end_MultiFuncCall(PG_FUNCTION_ARGS, FuncCallContext *funcctx);
+
+#define SRF_IS_FIRSTCALL() (fcinfo->flinfo->fn_extra == NULL)
+
+#define SRF_FIRSTCALL_INIT() init_MultiFuncCall(fcinfo)
+
+#define SRF_PERCALL_SETUP() per_MultiFuncCall(fcinfo)
+
+#define SRF_RETURN_NEXT(_funcctx, _result) \
+	do { \
+		ReturnSetInfo	   *rsi; \
+		(_funcctx)->call_cntr++; \
+		rsi = (ReturnSetInfo *) fcinfo->resultinfo; \
+		rsi->isDone = ExprMultipleResult; \
+		PG_RETURN_DATUM(_result); \
+	} while (0)
+
+#define SRF_RETURN_NEXT_NULL(_funcctx) \
+	do { \
+		ReturnSetInfo	   *rsi; \
+		(_funcctx)->call_cntr++; \
+		rsi = (ReturnSetInfo *) fcinfo->resultinfo; \
+		rsi->isDone = ExprMultipleResult; \
+		PG_RETURN_NULL(); \
+	} while (0)
+
+#define  SRF_RETURN_DONE(_funcctx) \
+	do { \
+		ReturnSetInfo	   *rsi; \
+		end_MultiFuncCall(fcinfo, _funcctx); \
+		rsi = (ReturnSetInfo *) fcinfo->resultinfo; \
+		rsi->isDone = ExprEndResult; \
+		PG_RETURN_NULL(); \
+	} while (0)
+
+/*----------
+ *	Support to ease writing of functions dealing with VARIADIC inputs
+ *----------
+ *
+ * This function extracts a set of argument values, types and NULL markers
+ * for a given input function. This returns a set of data:
+ * - **values includes the set of Datum values extracted.
+ * - **types the data type OID for each element.
+ * - **nulls tracks if an element is NULL.
+ *
+ * variadic_start indicates the argument number where the VARIADIC argument
+ * starts.
+ * convert_unknown set to true will enforce the conversion of arguments
+ * with unknown data type to text.
+ *
+ * The return result is the number of elements stored, or -1 in the case of
+ * "VARIADIC NULL".
+ */
+extern int	extract_variadic_args(FunctionCallInfo fcinfo, int variadic_start,
+								  bool convert_unknown, Datum **args,
+								  Oid **types, bool **nulls);
+
+#endif							/* FUNCAPI_H */