libpgquery-sys 0.1.0

/*--------------------------------------------------------------------
 * Symbols referenced in this file:
 * - plpgsql_compile_inline
 * - plpgsql_error_funcname
 * - plpgsql_check_syntax
 * - plpgsql_curr_compile
 * - plpgsql_compile_tmp_cxt
 * - plpgsql_DumpExecTree
 * - plpgsql_start_datums
 * - plpgsql_nDatums
 * - plpgsql_Datums
 * - datums_alloc
 * - datums_last
 * - plpgsql_build_variable
 * - plpgsql_adddatum
 * - plpgsql_build_record
 * - plpgsql_build_datatype
 * - plpgsql_parse_tripword
 * - plpgsql_build_recfield
 * - plpgsql_parse_dblword
 * - plpgsql_parse_word
 * - plpgsql_add_initdatums
 * - plpgsql_recognize_err_condition
 * - exception_label_map
 * - plpgsql_parse_err_condition
 * - plpgsql_parse_wordtype
 * - plpgsql_parse_wordrowtype
 * - plpgsql_parse_cwordtype
 * - plpgsql_parse_cwordrowtype
 * - plpgsql_parse_result
 * - plpgsql_finish_datums
 * - plpgsql_compile_error_callback
 * - add_dummy_return
 *--------------------------------------------------------------------
 */

/*-------------------------------------------------------------------------
 *
 * pl_comp.c		- Compiler part of the PL/pgSQL
 *			  procedural language
 *
 * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  src/pl/plpgsql/src/pl_comp.c
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include <ctype.h>

#include "access/htup_details.h"
#include "catalog/namespace.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "nodes/makefuncs.h"
#include "parser/parse_type.h"
#include "plpgsql.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/regproc.h"
#include "utils/rel.h"
#include "utils/syscache.h"
#include "utils/typcache.h"

/* ----------
 * Our own local and global variables
 * ----------
 */
__thread PLpgSQL_stmt_block *plpgsql_parse_result;


static __thread int	datums_alloc;

__thread int			plpgsql_nDatums;

__thread PLpgSQL_datum **plpgsql_Datums;

static __thread int	datums_last;


__thread char	   *plpgsql_error_funcname;

__thread bool		plpgsql_DumpExecTree = false;

__thread bool		plpgsql_check_syntax = false;


__thread PLpgSQL_function *plpgsql_curr_compile;


/* A context appropriate for short-term allocs during compilation */
__thread MemoryContext plpgsql_compile_tmp_cxt;


/* ----------
 * Hash table for compiled functions
 * ----------
 */


typedef struct plpgsql_hashent
{
	PLpgSQL_func_hashkey key;
	PLpgSQL_function *function;
} plpgsql_HashEnt;

#define FUNCS_PER_USER		128 /* initial table size */

/* ----------
 * Lookup table for EXCEPTION condition names
 * ----------
 */
typedef struct
{
	const char *label;
	int			sqlerrstate;
} ExceptionLabelMap;

static const ExceptionLabelMap exception_label_map[] = {
#include "plerrcodes.h"			/* pgrminclude ignore */
	{NULL, 0}
};


/* ----------
 * static prototypes
 * ----------
 */
static PLpgSQL_function *do_compile(FunctionCallInfo fcinfo,
									HeapTuple procTup,
									PLpgSQL_function *function,
									PLpgSQL_func_hashkey *hashkey,
									bool forValidator);
static void plpgsql_compile_error_callback(void *arg);
static void add_parameter_name(PLpgSQL_nsitem_type itemtype, int itemno, const char *name);
static void add_dummy_return(PLpgSQL_function *function);
static Node *plpgsql_pre_column_ref(ParseState *pstate, ColumnRef *cref);
static Node *plpgsql_post_column_ref(ParseState *pstate, ColumnRef *cref, Node *var);
static Node *plpgsql_param_ref(ParseState *pstate, ParamRef *pref);
static Node *resolve_column_ref(ParseState *pstate, PLpgSQL_expr *expr,
								ColumnRef *cref, bool error_if_no_field);
static Node *make_datum_param(PLpgSQL_expr *expr, int dno, int location);
static PLpgSQL_row *build_row_from_vars(PLpgSQL_variable **vars, int numvars);
static PLpgSQL_type *build_datatype(HeapTuple typeTup, int32 typmod,
									Oid collation, TypeName *origtypname);
static void compute_function_hashkey(FunctionCallInfo fcinfo,
									 Form_pg_proc procStruct,
									 PLpgSQL_func_hashkey *hashkey,
									 bool forValidator);
static void plpgsql_resolve_polymorphic_argtypes(int numargs,
												 Oid *argtypes, char *argmodes,
												 Node *call_expr, bool forValidator,
												 const char *proname);
static PLpgSQL_function *plpgsql_HashTableLookup(PLpgSQL_func_hashkey *func_key);
static void plpgsql_HashTableInsert(PLpgSQL_function *function,
									PLpgSQL_func_hashkey *func_key);
static void plpgsql_HashTableDelete(PLpgSQL_function *function);
static void delete_function(PLpgSQL_function *func);

/* ----------
 * plpgsql_compile		Make an execution tree for a PL/pgSQL function.
 *
 * If forValidator is true, we're only compiling for validation purposes,
 * and so some checks are skipped.
 *
 * Note: it's important for this to fall through quickly if the function
 * has already been compiled.
 * ----------
 */


/*
 * This is the slow part of plpgsql_compile().
 *
 * The passed-in "function" pointer is either NULL or an already-allocated
 * function struct to overwrite.
 *
 * While compiling a function, the CurrentMemoryContext is the
 * per-function memory context of the function we are compiling. That
 * means a palloc() will allocate storage with the same lifetime as
 * the function itself.
 *
 * Because palloc()'d storage will not be immediately freed, temporary
 * allocations should either be performed in a short-lived memory
 * context or explicitly pfree'd. Since not all backend functions are
 * careful about pfree'ing their allocations, it is also wise to
 * switch into a short-term context before calling into the
 * backend. An appropriate context for performing short-term
 * allocations is the plpgsql_compile_tmp_cxt.
 *
 * NB: this code is not re-entrant.  We assume that nothing we do here could
 * result in the invocation of another plpgsql function.
 */


/* ----------
 * plpgsql_compile_inline	Make an execution tree for an anonymous code block.
 *
 * Note: this is generally parallel to do_compile(); is it worth trying to
 * merge the two?
 *
 * Note: we assume the block will be thrown away so there is no need to build
 * persistent data structures.
 * ----------
 */
PLpgSQL_function *
plpgsql_compile_inline(char *proc_source)
{
	char	   *func_name = "inline_code_block";
	PLpgSQL_function *function;
	ErrorContextCallback plerrcontext;
	PLpgSQL_variable *var;
	int			parse_rc;
	MemoryContext func_cxt;

	/*
	 * Setup the scanner input and error info.  We assume that this function
	 * cannot be invoked recursively, so there's no need to save and restore
	 * the static variables used here.
	 */
	plpgsql_scanner_init(proc_source);

	plpgsql_error_funcname = func_name;

	/*
	 * Setup error traceback support for ereport()
	 */
	plerrcontext.callback = plpgsql_compile_error_callback;
	plerrcontext.arg = proc_source;
	plerrcontext.previous = error_context_stack;
	error_context_stack = &plerrcontext;

	/* Do extra syntax checking if check_function_bodies is on */
	plpgsql_check_syntax = check_function_bodies;

	/* Function struct does not live past current statement */
	function = (PLpgSQL_function *) palloc0(sizeof(PLpgSQL_function));

	plpgsql_curr_compile = function;

	/*
	 * All the rest of the compile-time storage (e.g. parse tree) is kept in
	 * its own memory context, so it can be reclaimed easily.
	 */
	func_cxt = AllocSetContextCreate(CurrentMemoryContext,
									 "PL/pgSQL inline code context",
									 ALLOCSET_DEFAULT_SIZES);
	plpgsql_compile_tmp_cxt = MemoryContextSwitchTo(func_cxt);

	function->fn_signature = pstrdup(func_name);
	function->fn_is_trigger = PLPGSQL_NOT_TRIGGER;
	function->fn_input_collation = InvalidOid;
	function->fn_cxt = func_cxt;
	function->out_param_varno = -1; /* set up for no OUT param */
	function->resolve_option = plpgsql_variable_conflict;
	function->print_strict_params = plpgsql_print_strict_params;

	/*
	 * don't do extra validation for inline code as we don't want to add spam
	 * at runtime
	 */
	function->extra_warnings = 0;
	function->extra_errors = 0;

	function->nstatements = 0;

	plpgsql_ns_init();
	plpgsql_ns_push(func_name, PLPGSQL_LABEL_BLOCK);
	plpgsql_DumpExecTree = false;
	plpgsql_start_datums();

	/* Set up as though in a function returning VOID */
	function->fn_rettype = VOIDOID;
	function->fn_retset = false;
	function->fn_retistuple = false;
	function->fn_retisdomain = false;
	function->fn_prokind = PROKIND_FUNCTION;
	/* a bit of hardwired knowledge about type VOID here */
	function->fn_retbyval = true;
	function->fn_rettyplen = sizeof(int32);

	/*
	 * Remember if function is STABLE/IMMUTABLE.  XXX would it be better to
	 * set this true inside a read-only transaction?  Not clear.
	 */
	function->fn_readonly = false;

	/*
	 * Create the magic FOUND variable.
	 */
	var = plpgsql_build_variable("found", 0,
								 plpgsql_build_datatype(BOOLOID,
														-1,
														InvalidOid,
														NULL),
								 true);
	function->found_varno = var->dno;

	/*
	 * Now parse the function's text
	 */
	parse_rc = plpgsql_yyparse();
	if (parse_rc != 0)
		elog(ERROR, "plpgsql parser returned %d", parse_rc);
	function->action = plpgsql_parse_result;

	plpgsql_scanner_finish();

	/*
	 * If it returns VOID (always true at the moment), we allow control to
	 * fall off the end without an explicit RETURN statement.
	 */
	if (function->fn_rettype == VOIDOID)
		add_dummy_return(function);

	/*
	 * Complete the function's info
	 */
	function->fn_nargs = 0;

	plpgsql_finish_datums(function);

	/*
	 * Pop the error context stack
	 */
	error_context_stack = plerrcontext.previous;
	plpgsql_error_funcname = NULL;

	plpgsql_check_syntax = false;

	MemoryContextSwitchTo(plpgsql_compile_tmp_cxt);
	plpgsql_compile_tmp_cxt = NULL;
	return function;
}


/*
 * error context callback to let us supply a call-stack traceback.
 * If we are validating or executing an anonymous code block, the function
 * source text is passed as an argument.
 */
static void
plpgsql_compile_error_callback(void *arg)
{
	if (arg)
	{
		/*
		 * Try to convert syntax error position to reference text of original
		 * CREATE FUNCTION or DO command.
		 */
		if (function_parse_error_transpose((const char *) arg))
			return;

		/*
		 * Done if a syntax error position was reported; otherwise we have to
		 * fall back to a "near line N" report.
		 */
	}

	if (plpgsql_error_funcname)
		errcontext("compilation of PL/pgSQL function \"%s\" near line %d",
				   plpgsql_error_funcname, plpgsql_latest_lineno());
}


/*
 * Add a name for a function parameter to the function's namespace
 */


/*
 * Add a dummy RETURN statement to the given function's body
 */
static void
add_dummy_return(PLpgSQL_function *function)
{
	/*
	 * If the outer block has an EXCEPTION clause, we need to make a new outer
	 * block, since the added RETURN shouldn't act like it is inside the
	 * EXCEPTION clause.
	 */
	if (function->action->exceptions != NULL)
	{
		PLpgSQL_stmt_block *new;

		new = palloc0(sizeof(PLpgSQL_stmt_block));
		new->cmd_type = PLPGSQL_STMT_BLOCK;
		new->stmtid = ++function->nstatements;
		new->body = list_make1(function->action);

		function->action = new;
	}
	if (function->action->body == NIL ||
		((PLpgSQL_stmt *) llast(function->action->body))->cmd_type != PLPGSQL_STMT_RETURN)
	{
		PLpgSQL_stmt_return *new;

		new = palloc0(sizeof(PLpgSQL_stmt_return));
		new->cmd_type = PLPGSQL_STMT_RETURN;
		new->stmtid = ++function->nstatements;
		new->expr = NULL;
		new->retvarno = function->out_param_varno;

		function->action->body = lappend(function->action->body, new);
	}
}


/*
 * plpgsql_parser_setup		set up parser hooks for dynamic parameters
 *
 * Note: this routine, and the hook functions it prepares for, are logically
 * part of plpgsql parsing.  But they actually run during function execution,
 * when we are ready to evaluate a SQL query or expression that has not
 * previously been parsed and planned.
 */


/*
 * plpgsql_pre_column_ref		parser callback before parsing a ColumnRef
 */


/*
 * plpgsql_post_column_ref		parser callback after parsing a ColumnRef
 */


/*
 * plpgsql_param_ref		parser callback for ParamRefs ($n symbols)
 */


/*
 * resolve_column_ref		attempt to resolve a ColumnRef as a plpgsql var
 *
 * Returns the translated node structure, or NULL if name not found
 *
 * error_if_no_field tells whether to throw error or quietly return NULL if
 * we are able to match a record/row name but don't find a field name match.
 */


/*
 * Helper for columnref parsing: build a Param referencing a plpgsql datum,
 * and make sure that that datum is listed in the expression's paramnos.
 */



/* ----------
 * plpgsql_parse_word		The scanner calls this to postparse
 *				any single word that is not a reserved keyword.
 *
 * word1 is the downcased/dequoted identifier; it must be palloc'd in the
 * function's long-term memory context.
 *
 * yytxt is the original token text; we need this to check for quoting,
 * so that later checks for unreserved keywords work properly.
 *
 * We attempt to recognize the token as a variable only if lookup is true
 * and the plpgsql_IdentifierLookup context permits it.
 *
 * If recognized as a variable, fill in *wdatum and return true;
 * if not recognized, fill in *word and return false.
 * (Note: those two pointers actually point to members of the same union,
 * but for notational reasons we pass them separately.)
 * ----------
 */
bool
plpgsql_parse_word(char *word1, const char *yytxt, bool lookup,
				   PLwdatum *wdatum, PLword *word)
{
	PLpgSQL_nsitem *ns;

	/*
	 * We should not lookup variables in DECLARE sections.  In SQL
	 * expressions, there's no need to do so either --- lookup will happen
	 * when the expression is compiled.
	 */
	if (lookup && plpgsql_IdentifierLookup == IDENTIFIER_LOOKUP_NORMAL)
	{
		/*
		 * Do a lookup in the current namespace stack
		 */
		ns = plpgsql_ns_lookup(plpgsql_ns_top(), false,
							   word1, NULL, NULL,
							   NULL);

		if (ns != NULL)
		{
			switch (ns->itemtype)
			{
				case PLPGSQL_NSTYPE_VAR:
				case PLPGSQL_NSTYPE_REC:
					wdatum->datum = plpgsql_Datums[ns->itemno];
					wdatum->ident = word1;
					wdatum->quoted = (yytxt[0] == '"');
					wdatum->idents = NIL;
					return true;

				default:
					/* plpgsql_ns_lookup should never return anything else */
					elog(ERROR, "unrecognized plpgsql itemtype: %d",
						 ns->itemtype);
			}
		}
	}

	/*
	 * Nothing found - up to now it's a word without any special meaning for
	 * us.
	 */
	word->ident = word1;
	word->quoted = (yytxt[0] == '"');
	return false;
}


/* ----------
 * plpgsql_parse_dblword		Same lookup for two words
 *					separated by a dot.
 * ----------
 */
bool
plpgsql_parse_dblword(char *word1, char *word2,
					  PLwdatum *wdatum, PLcword *cword)
{
	PLpgSQL_nsitem *ns;
	List	   *idents;
	int			nnames;

	idents = list_make2(makeString(word1),
						makeString(word2));

	/*
	 * We should do nothing in DECLARE sections.  In SQL expressions, we
	 * really only need to make sure that RECFIELD datums are created when
	 * needed.
	 */
	if (plpgsql_IdentifierLookup != IDENTIFIER_LOOKUP_DECLARE)
	{
		/*
		 * Do a lookup in the current namespace stack
		 */
		ns = plpgsql_ns_lookup(plpgsql_ns_top(), false,
							   word1, word2, NULL,
							   &nnames);
		if (ns != NULL)
		{
			switch (ns->itemtype)
			{
				case PLPGSQL_NSTYPE_VAR:
					/* Block-qualified reference to scalar variable. */
					wdatum->datum = plpgsql_Datums[ns->itemno];
					wdatum->ident = NULL;
					wdatum->quoted = false; /* not used */
					wdatum->idents = idents;
					return true;

				case PLPGSQL_NSTYPE_REC:
					if (nnames == 1)
					{
						/*
						 * First word is a record name, so second word could
						 * be a field in this record.  We build a RECFIELD
						 * datum whether it is or not --- any error will be
						 * detected later.
						 */
						PLpgSQL_rec *rec;
						PLpgSQL_recfield *new;

						rec = (PLpgSQL_rec *) (plpgsql_Datums[ns->itemno]);
						new = plpgsql_build_recfield(rec, word2);

						wdatum->datum = (PLpgSQL_datum *) new;
					}
					else
					{
						/* Block-qualified reference to record variable. */
						wdatum->datum = plpgsql_Datums[ns->itemno];
					}
					wdatum->ident = NULL;
					wdatum->quoted = false; /* not used */
					wdatum->idents = idents;
					return true;

				default:
					break;
			}
		}
	}

	/* Nothing found */
	cword->idents = idents;
	return false;
}


/* ----------
 * plpgsql_parse_tripword		Same lookup for three words
 *					separated by dots.
 * ----------
 */
bool
plpgsql_parse_tripword(char *word1, char *word2, char *word3,
					   PLwdatum *wdatum, PLcword *cword)
{
	PLpgSQL_nsitem *ns;
	List	   *idents;
	int			nnames;

	idents = list_make3(makeString(word1),
						makeString(word2),
						makeString(word3));

	/*
	 * We should do nothing in DECLARE sections.  In SQL expressions, we
	 * really only need to make sure that RECFIELD datums are created when
	 * needed.
	 */
	if (plpgsql_IdentifierLookup != IDENTIFIER_LOOKUP_DECLARE)
	{
		/*
		 * Do a lookup in the current namespace stack. Must find a qualified
		 * reference, else ignore.
		 */
		ns = plpgsql_ns_lookup(plpgsql_ns_top(), false,
							   word1, word2, word3,
							   &nnames);
		if (ns != NULL && nnames == 2)
		{
			switch (ns->itemtype)
			{
				case PLPGSQL_NSTYPE_REC:
					{
						/*
						 * words 1/2 are a record name, so third word could be
						 * a field in this record.
						 */
						PLpgSQL_rec *rec;
						PLpgSQL_recfield *new;

						rec = (PLpgSQL_rec *) (plpgsql_Datums[ns->itemno]);
						new = plpgsql_build_recfield(rec, word3);

						wdatum->datum = (PLpgSQL_datum *) new;
						wdatum->ident = NULL;
						wdatum->quoted = false; /* not used */
						wdatum->idents = idents;
						return true;
					}

				default:
					break;
			}
		}
	}

	/* Nothing found */
	cword->idents = idents;
	return false;
}


/* ----------
 * plpgsql_parse_wordtype	The scanner found word%TYPE. word can be
 *				a variable name or a basetype.
 *
 * Returns datatype struct, or NULL if no match found for word.
 * ----------
 */
PLpgSQL_type * plpgsql_parse_wordtype(char *ident) { return NULL; }



/* ----------
 * plpgsql_parse_cwordtype		Same lookup for compositeword%TYPE
 * ----------
 */
PLpgSQL_type * plpgsql_parse_cwordtype(List *idents) { return NULL; }


/* ----------
 * plpgsql_parse_wordrowtype		Scanner found word%ROWTYPE.
 *					So word must be a table name.
 * ----------
 */
PLpgSQL_type * plpgsql_parse_wordrowtype(char *ident) { return NULL; }


/* ----------
 * plpgsql_parse_cwordrowtype		Scanner found compositeword%ROWTYPE.
 *			So word must be a namespace qualified table name.
 * ----------
 */
PLpgSQL_type * plpgsql_parse_cwordrowtype(List *idents) { return NULL; }


/*
 * plpgsql_build_variable - build a datum-array entry of a given
 * datatype
 *
 * The returned struct may be a PLpgSQL_var or PLpgSQL_rec
 * depending on the given datatype, and is allocated via
 * palloc.  The struct is automatically added to the current datum
 * array, and optionally to the current namespace.
 */
PLpgSQL_variable *
plpgsql_build_variable(const char *refname, int lineno, PLpgSQL_type *dtype,
					   bool add2namespace)
{
	PLpgSQL_variable *result;

	switch (dtype->ttype)
	{
		case PLPGSQL_TTYPE_SCALAR:
			{
				/* Ordinary scalar datatype */
				PLpgSQL_var *var;

				var = palloc0(sizeof(PLpgSQL_var));
				var->dtype = PLPGSQL_DTYPE_VAR;
				var->refname = pstrdup(refname);
				var->lineno = lineno;
				var->datatype = dtype;
				/* other fields are left as 0, might be changed by caller */

				/* preset to NULL */
				var->value = 0;
				var->isnull = true;
				var->freeval = false;

				plpgsql_adddatum((PLpgSQL_datum *) var);
				if (add2namespace)
					plpgsql_ns_additem(PLPGSQL_NSTYPE_VAR,
									   var->dno,
									   refname);
				result = (PLpgSQL_variable *) var;
				break;
			}
		case PLPGSQL_TTYPE_REC:
			{
				/* Composite type -- build a record variable */
				PLpgSQL_rec *rec;

				rec = plpgsql_build_record(refname, lineno,
										   dtype, dtype->typoid,
										   add2namespace);
				result = (PLpgSQL_variable *) rec;
				break;
			}
		case PLPGSQL_TTYPE_PSEUDO:
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("variable \"%s\" has pseudo-type %s",
							refname, format_type_be(dtype->typoid))));
			result = NULL;		/* keep compiler quiet */
			break;
		default:
			elog(ERROR, "unrecognized ttype: %d", dtype->ttype);
			result = NULL;		/* keep compiler quiet */
			break;
	}

	return result;
}

/*
 * Build empty named record variable, and optionally add it to namespace
 */
PLpgSQL_rec *
plpgsql_build_record(const char *refname, int lineno,
					 PLpgSQL_type *dtype, Oid rectypeid,
					 bool add2namespace)
{
	PLpgSQL_rec *rec;

	rec = palloc0(sizeof(PLpgSQL_rec));
	rec->dtype = PLPGSQL_DTYPE_REC;
	rec->refname = pstrdup(refname);
	rec->lineno = lineno;
	/* other fields are left as 0, might be changed by caller */
	rec->datatype = dtype;
	rec->rectypeid = rectypeid;
	rec->firstfield = -1;
	rec->erh = NULL;
	plpgsql_adddatum((PLpgSQL_datum *) rec);
	if (add2namespace)
		plpgsql_ns_additem(PLPGSQL_NSTYPE_REC, rec->dno, rec->refname);

	return rec;
}

/*
 * Build a row-variable data structure given the component variables.
 * Include a rowtupdesc, since we will need to materialize the row result.
 */


/*
 * Build a RECFIELD datum for the named field of the specified record variable
 *
 * If there's already such a datum, just return it; we don't need duplicates.
 */
PLpgSQL_recfield *
plpgsql_build_recfield(PLpgSQL_rec *rec, const char *fldname)
{
	PLpgSQL_recfield *recfield;
	int			i;

	/* search for an existing datum referencing this field */
	i = rec->firstfield;
	while (i >= 0)
	{
		PLpgSQL_recfield *fld = (PLpgSQL_recfield *) plpgsql_Datums[i];

		Assert(fld->dtype == PLPGSQL_DTYPE_RECFIELD &&
			   fld->recparentno == rec->dno);
		if (strcmp(fld->fieldname, fldname) == 0)
			return fld;
		i = fld->nextfield;
	}

	/* nope, so make a new one */
	recfield = palloc0(sizeof(PLpgSQL_recfield));
	recfield->dtype = PLPGSQL_DTYPE_RECFIELD;
	recfield->fieldname = pstrdup(fldname);
	recfield->recparentno = rec->dno;
	recfield->rectupledescid = INVALID_TUPLEDESC_IDENTIFIER;

	plpgsql_adddatum((PLpgSQL_datum *) recfield);

	/* now we can link it into the parent's chain */
	recfield->nextfield = rec->firstfield;
	rec->firstfield = recfield->dno;

	return recfield;
}

/*
 * plpgsql_build_datatype
 *		Build PLpgSQL_type struct given type OID, typmod, collation,
 *		and type's parsed name.
 *
 * If collation is not InvalidOid then it overrides the type's default
 * collation.  But collation is ignored if the datatype is non-collatable.
 *
 * origtypname is the parsed form of what the user wrote as the type name.
 * It can be NULL if the type could not be a composite type, or if it was
 * identified by OID to begin with (e.g., it's a function argument type).
 */
PLpgSQL_type * plpgsql_build_datatype(Oid typeOid, int32 typmod, Oid collation, TypeName *origtypname) { PLpgSQL_type *typ; typ = (PLpgSQL_type *) palloc0(sizeof(PLpgSQL_type)); typ->typname = pstrdup("UNKNOWN"); typ->ttype = PLPGSQL_TTYPE_SCALAR; return typ; }


/*
 * Utility subroutine to make a PLpgSQL_type struct given a pg_type entry
 * and additional details (see comments for plpgsql_build_datatype).
 */


/*
 *	plpgsql_recognize_err_condition
 *		Check condition name and translate it to SQLSTATE.
 *
 * Note: there are some cases where the same condition name has multiple
 * entries in the table.  We arbitrarily return the first match.
 */
int
plpgsql_recognize_err_condition(const char *condname, bool allow_sqlstate)
{
	int			i;

	if (allow_sqlstate)
	{
		if (strlen(condname) == 5 &&
			strspn(condname, "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ") == 5)
			return MAKE_SQLSTATE(condname[0],
								 condname[1],
								 condname[2],
								 condname[3],
								 condname[4]);
	}

	for (i = 0; exception_label_map[i].label != NULL; i++)
	{
		if (strcmp(condname, exception_label_map[i].label) == 0)
			return exception_label_map[i].sqlerrstate;
	}

	ereport(ERROR,
			(errcode(ERRCODE_UNDEFINED_OBJECT),
			 errmsg("unrecognized exception condition \"%s\"",
					condname)));
	return 0;					/* keep compiler quiet */
}

/*
 * plpgsql_parse_err_condition
 *		Generate PLpgSQL_condition entry(s) for an exception condition name
 *
 * This has to be able to return a list because there are some duplicate
 * names in the table of error code names.
 */
PLpgSQL_condition *
plpgsql_parse_err_condition(char *condname)
{
	int			i;
	PLpgSQL_condition *new;
	PLpgSQL_condition *prev;

	/*
	 * XXX Eventually we will want to look for user-defined exception names
	 * here.
	 */

	/*
	 * OTHERS is represented as code 0 (which would map to '00000', but we
	 * have no need to represent that as an exception condition).
	 */
	if (strcmp(condname, "others") == 0)
	{
		new = palloc(sizeof(PLpgSQL_condition));
		new->sqlerrstate = 0;
		new->condname = condname;
		new->next = NULL;
		return new;
	}

	prev = NULL;
	for (i = 0; exception_label_map[i].label != NULL; i++)
	{
		if (strcmp(condname, exception_label_map[i].label) == 0)
		{
			new = palloc(sizeof(PLpgSQL_condition));
			new->sqlerrstate = exception_label_map[i].sqlerrstate;
			new->condname = condname;
			new->next = prev;
			prev = new;
		}
	}

	if (!prev)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("unrecognized exception condition \"%s\"",
						condname)));

	return prev;
}

/* ----------
 * plpgsql_start_datums			Initialize datum list at compile startup.
 * ----------
 */
void
plpgsql_start_datums(void)
{
	datums_alloc = 128;
	plpgsql_nDatums = 0;
	/* This is short-lived, so needn't allocate in function's cxt */
	plpgsql_Datums = MemoryContextAlloc(plpgsql_compile_tmp_cxt,
										sizeof(PLpgSQL_datum *) * datums_alloc);
	/* datums_last tracks what's been seen by plpgsql_add_initdatums() */
	datums_last = 0;
}

/* ----------
 * plpgsql_adddatum			Add a variable, record or row
 *					to the compiler's datum list.
 * ----------
 */
void
plpgsql_adddatum(PLpgSQL_datum *newdatum)
{
	if (plpgsql_nDatums == datums_alloc)
	{
		datums_alloc *= 2;
		plpgsql_Datums = repalloc(plpgsql_Datums, sizeof(PLpgSQL_datum *) * datums_alloc);
	}

	newdatum->dno = plpgsql_nDatums;
	plpgsql_Datums[plpgsql_nDatums++] = newdatum;
}

/* ----------
 * plpgsql_finish_datums	Copy completed datum info into function struct.
 * ----------
 */
void
plpgsql_finish_datums(PLpgSQL_function *function)
{
	Size		copiable_size = 0;
	int			i;

	function->ndatums = plpgsql_nDatums;
	function->datums = palloc(sizeof(PLpgSQL_datum *) * plpgsql_nDatums);
	for (i = 0; i < plpgsql_nDatums; i++)
	{
		function->datums[i] = plpgsql_Datums[i];

		/* This must agree with copy_plpgsql_datums on what is copiable */
		switch (function->datums[i]->dtype)
		{
			case PLPGSQL_DTYPE_VAR:
			case PLPGSQL_DTYPE_PROMISE:
				copiable_size += MAXALIGN(sizeof(PLpgSQL_var));
				break;
			case PLPGSQL_DTYPE_REC:
				copiable_size += MAXALIGN(sizeof(PLpgSQL_rec));
				break;
			default:
				break;
		}
	}
	function->copiable_size = copiable_size;
}


/* ----------
 * plpgsql_add_initdatums		Make an array of the datum numbers of
 *					all the initializable datums created since the last call
 *					to this function.
 *
 * If varnos is NULL, we just forget any datum entries created since the
 * last call.
 *
 * This is used around a DECLARE section to create a list of the datums
 * that have to be initialized at block entry.  Note that datums can also
 * be created elsewhere than DECLARE, eg by a FOR-loop, but it is then
 * the responsibility of special-purpose code to initialize them.
 * ----------
 */
int
plpgsql_add_initdatums(int **varnos)
{
	int			i;
	int			n = 0;

	/*
	 * The set of dtypes recognized here must match what exec_stmt_block()
	 * cares about (re)initializing at block entry.
	 */
	for (i = datums_last; i < plpgsql_nDatums; i++)
	{
		switch (plpgsql_Datums[i]->dtype)
		{
			case PLPGSQL_DTYPE_VAR:
			case PLPGSQL_DTYPE_REC:
				n++;
				break;

			default:
				break;
		}
	}

	if (varnos != NULL)
	{
		if (n > 0)
		{
			*varnos = (int *) palloc(sizeof(int) * n);

			n = 0;
			for (i = datums_last; i < plpgsql_nDatums; i++)
			{
				switch (plpgsql_Datums[i]->dtype)
				{
					case PLPGSQL_DTYPE_VAR:
					case PLPGSQL_DTYPE_REC:
						(*varnos)[n++] = plpgsql_Datums[i]->dno;

					default:
						break;
				}
			}
		}
		else
			*varnos = NULL;
	}

	datums_last = plpgsql_nDatums;
	return n;
}


/*
 * Compute the hashkey for a given function invocation
 *
 * The hashkey is returned into the caller-provided storage at *hashkey.
 */


/*
 * This is the same as the standard resolve_polymorphic_argtypes() function,
 * but with a special case for validation: assume that polymorphic arguments
 * are integer, integer-array or integer-range.  Also, we go ahead and report
 * the error if we can't resolve the types.
 */


/*
 * delete_function - clean up as much as possible of a stale function cache
 *
 * We can't release the PLpgSQL_function struct itself, because of the
 * possibility that there are fn_extra pointers to it.  We can release
 * the subsidiary storage, but only if there are no active evaluations
 * in progress.  Otherwise we'll just leak that storage.  Since the
 * case would only occur if a pg_proc update is detected during a nested
 * recursive call on the function, a leak seems acceptable.
 *
 * Note that this can be called more than once if there are multiple fn_extra
 * pointers to the same function cache.  Hence be careful not to do things
 * twice.
 */


/* exported so we can call it from _PG_init() */