parse_coerce.c

/*-------------------------------------------------------------------------
 *
 * parse_coerce.c
 *		handle type coercions/conversions for parser
 *
 * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  src/backend/parser/parse_coerce.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/htup_details.h"
#include "catalog/pg_cast.h"
#include "catalog/pg_class.h"
#include "catalog/pg_inherits_fn.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "parser/parse_coerce.h"
#include "parser/parse_relation.h"
#include "parser/parse_type.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "utils/typcache.h"


static Node *coerce_type_typmod(Node *node,
				   Oid targetTypeId, int32 targetTypMod,
				   CoercionForm cformat, int location,
				   bool isExplicit, bool hideInputCoercion);
static void hide_coercion_node(Node *node);
static Node *build_coercion_expression(Node *node,
						  CoercionPathType pathtype,
						  Oid funcId,
						  Oid targetTypeId, int32 targetTypMod,
						  CoercionForm cformat, int location,
						  bool isExplicit);
static Node *coerce_record_to_complex(ParseState *pstate, Node *node,
						 Oid targetTypeId,
						 CoercionContext ccontext,
						 CoercionForm cformat,
						 int location);
static bool is_complex_array(Oid typid);
static bool typeIsOfTypedTable(Oid reltypeId, Oid reloftypeId);


/*
 * coerce_to_target_type()
 *		Convert an expression to a target type and typmod.
 *
 * This is the general-purpose entry point for arbitrary type coercion
 * operations.	Direct use of the component operations can_coerce_type,
 * coerce_type, and coerce_type_typmod should be restricted to special
 * cases (eg, when the conversion is expected to succeed).
 *
 * Returns the possibly-transformed expression tree, or NULL if the type
 * conversion is not possible.	(We do this, rather than ereport'ing directly,
 * so that callers can generate custom error messages indicating context.)
 *
 * pstate - parse state (can be NULL, see coerce_type)
 * expr - input expression tree (already transformed by transformExpr)
 * exprtype - result type of expr
 * targettype - desired result type