text: /**********************************************************************
   * plperl.c - perl as a procedural language for PostgreSQL
   *
   *	  src/pl/plperl/plperl.c
   *
   **********************************************************************/
  
  #include "postgres.h"
  /* Defined by Perl */
  #undef _
  
  /* system stuff */
  #include <ctype.h>
  #include <fcntl.h>
  #include <unistd.h>
  #include <locale.h>
  
  /* postgreSQL stuff */
  #include "access/htup_details.h"
  #include "access/xact.h"
  #include "catalog/pg_language.h"
  #include "catalog/pg_proc.h"
  #include "catalog/pg_type.h"
  #include "commands/event_trigger.h"
  #include "commands/trigger.h"
  #include "executor/spi.h"
  #include "funcapi.h"
  #include "mb/pg_wchar.h"
  #include "miscadmin.h"
  #include "nodes/makefuncs.h"
  #include "parser/parse_type.h"
  #include "storage/ipc.h"
  #include "tcop/tcopprot.h"
  #include "utils/builtins.h"
  #include "utils/fmgroids.h"
  #include "utils/guc.h"
  #include "utils/hsearch.h"
  #include "utils/lsyscache.h"
  #include "utils/memutils.h"
  #include "utils/rel.h"
  #include "utils/syscache.h"
  #include "utils/typcache.h"
  
  /* define our text domain for translations */
  #undef TEXTDOMAIN
  #define TEXTDOMAIN PG_TEXTDOMAIN("plperl")
  
  /* perl stuff */
  #include "plperl.h"
  #include "plperl_helpers.h"
  
  /* string literal macros defining chunks of perl code */
  #include "perlchunks.h"
  /* defines PLPERL_SET_OPMASK */
  #include "plperl_opmask.h"
  
  EXTERN_C void boot_DynaLoader(pTHX_ CV *cv);
  EXTERN_C void boot_PostgreSQL__InServer__Util(pTHX_ CV *cv);
  EXTERN_C void boot_PostgreSQL__InServer__SPI(pTHX_ CV *cv);
  
  PG_MODULE_MAGIC;
  
  
  /**********************************************************************
   * Information associated with a Perl interpreter.	We have one interpreter
   * that is used for all plperlu (untrusted) functions.	For plperl (trusted)
   * functions, there is a separate interpreter for each effective SQL userid.
   * (This is needed to ensure that an unprivileged user can't inject Perl code
   * that'll be executed with the privileges of some other SQL user.)
   *
   * The plperl_interp_desc structs are kept in a Postgres hash table indexed
   * by userid OID, with OID 0 used for the single untrusted interpreter.
   * Once created, an interpreter is kept for the life of the process.
   *
   * We start out by creating a "held" interpreter, which we initialize
   * only as far as we can do without deciding if it will be trusted or
   * untrusted.  Later, when we first need to run a plperl or plperlu
   * function, we complete the initialization appropriately and move the
   * PerlInterpreter pointer into the plperl_interp_hash hashtable.  If after
   * that we need more interpreters, we create them as needed if we can, or
   * fail if the Perl build doesn't support multiple interpreters.
   *
   * The reason for all the dancing about with a held interpreter is to make
   * it possible for people to preload a lot of Perl code at postmaster startup
   * (using plperl.on_init) and then use that code in backends.  Of course this
   * will only work for the first interpreter created in any backend, but it's
   * still useful with that restriction.
   **********************************************************************/
  typedef struct plperl_interp_desc
  {
  	Oid			user_id;		/* Hash key (must be first!) */
  	PerlInterpreter *interp;	/* The interpreter */
  	HTAB	   *query_hash;		/* plperl_query_entry structs */
  } plperl_interp_desc;
  
  
  /**********************************************************************
   * The information we cache about loaded procedures
   *
   * The refcount field counts the struct's reference from the hash table shown
   * below, plus one reference for each function call level that is using the
   * struct.	We can release the struct, and the associated Perl sub, when the
   * refcount goes to zero.
   **********************************************************************/
  typedef struct plperl_proc_desc
  {
  	char	   *proname;		/* user name of procedure */
  	TransactionId fn_xmin;		/* xmin/TID of procedure's pg_proc tuple */
  	ItemPointerData fn_tid;
  	int			refcount;		/* reference count of this struct */
  	SV		   *reference;		/* CODE reference for Perl sub */
  	plperl_interp_desc *interp; /* interpreter it's created in */
  	bool		fn_readonly;	/* is function readonly (not volatile)? */
  	bool		lanpltrusted;	/* is it plperl, rather than plperlu? */
  	bool		fn_retistuple;	/* true, if function returns tuple */
  	bool		fn_retisset;	/* true, if function returns set */
  	bool		fn_retisarray;	/* true if function returns array */
  	/* Conversion info for function's result type: */
  	Oid			result_oid;		/* Oid of result type */
  	FmgrInfo	result_in_func; /* I/O function and arg for result type */
  	Oid			result_typioparam;
  	/* Conversion info for function's argument types: */
  	int			nargs;
  	FmgrInfo	arg_out_func[FUNC_MAX_ARGS];
  	bool		arg_is_rowtype[FUNC_MAX_ARGS];
  	Oid			arg_arraytype[FUNC_MAX_ARGS];	/* InvalidOid if not an array */
  } plperl_proc_desc;
  
  #define increment_prodesc_refcount(prodesc)  \
  	((prodesc)->refcount++)
  #define decrement_prodesc_refcount(prodesc)  \
  	do { \
  		if (--((prodesc)->refcount) <= 0) \
  			free_plperl_function(prodesc); \
  	} while(0)
  
  /**********************************************************************
   * For speedy lookup, we maintain a hash table mapping from
   * function OID + trigger flag + user OID to plperl_proc_desc pointers.
   * The reason the plperl_proc_desc struct isn't directly part of the hash
   * entry is to simplify recovery from errors during compile_plperl_function.
   *
   * Note: if the same function is called by multiple userIDs within a session,
   * there will be a separate plperl_proc_desc entry for each userID in the case
   * of plperl functions, but only one entry for plperlu functions, because we
   * set user_id = 0 for that case.  If the user redeclares the same function
   * from plperl to plperlu or vice versa, there might be multiple
   * plperl_proc_ptr entries in the hashtable, but only one is valid.
   **********************************************************************/
  typedef struct plperl_proc_key
  {
  	Oid			proc_id;		/* Function OID */
  
  	/*
  	 * is_trigger is really a bool, but declare as Oid to ensure this struct
  	 * contains no padding
  	 */
  	Oid			is_trigger;		/* is it a trigger function? */
  	Oid			user_id;		/* User calling the function, or 0 */
  } plperl_proc_key;
  
  typedef struct plperl_proc_ptr
  {
  	plperl_proc_key proc_key;	/* Hash key (must be first!) */
  	plperl_proc_desc *proc_ptr;
  } plperl_proc_ptr;
  
  /*
   * The information we cache for the duration of a single call to a
   * function.
   */
  typedef struct plperl_call_data
  {
  	plperl_proc_desc *prodesc;
  	FunctionCallInfo fcinfo;
  	Tuplestorestate *tuple_store;
  	TupleDesc	ret_tdesc;
  	MemoryContext tmp_cxt;
  } plperl_call_data;
  
  /**********************************************************************
   * The information we cache about prepared and saved plans
   **********************************************************************/
  typedef struct plperl_query_desc
  {
  	char		qname[24];
  	MemoryContext plan_cxt;		/* context holding this struct */
  	SPIPlanPtr	plan;
  	int			nargs;
  	Oid		   *argtypes;
  	FmgrInfo   *arginfuncs;
  	Oid		   *argtypioparams;
  } plperl_query_desc;
  
  /* hash table entry for query desc	*/
  
  typedef struct plperl_query_entry
  {
  	char		query_name[NAMEDATALEN];
  	plperl_query_desc *query_data;
  } plperl_query_entry;
  
  /**********************************************************************
   * Information for PostgreSQL - Perl array conversion.
   **********************************************************************/
  typedef struct plperl_array_info
  {
  	int			ndims;
  	bool		elem_is_rowtype;	/* 't' if element type is a rowtype */
  	Datum	   *elements;
  	bool	   *nulls;
  	int		   *nelems;
  	FmgrInfo	proc;
  } plperl_array_info;
  
  /**********************************************************************
   * Global data
   **********************************************************************/
  
  static HTAB *plperl_interp_hash = NULL;
  static HTAB *plperl_proc_hash = NULL;
  static plperl_interp_desc *plperl_active_interp = NULL;
  
  /* If we have an unassigned "held" interpreter, it's stored here */
  static PerlInterpreter *plperl_held_interp = NULL;
  
  /* GUC variables */
  static bool plperl_use_strict = false;
  static char *plperl_on_init = NULL;
  static char *plperl_on_plperl_init = NULL;
  static char *plperl_on_plperlu_init = NULL;
  
  static bool plperl_ending = false;
  static OP  *(*pp_require_orig) (pTHX) = NULL;
  static char plperl_opmask[MAXO];
  
  /* this is saved and restored by plperl_call_handler */
  static plperl_call_data *current_call_data = NULL;
  
  /**********************************************************************
   * Forward declarations
   **********************************************************************/
  Datum		plperl_call_handler(PG_FUNCTION_ARGS);
  Datum		plperl_inline_handler(PG_FUNCTION_ARGS);
  Datum		plperl_validator(PG_FUNCTION_ARGS);
  Datum		plperlu_call_handler(PG_FUNCTION_ARGS);
  Datum		plperlu_inline_handler(PG_FUNCTION_ARGS);
  Datum		plperlu_validator(PG_FUNCTION_ARGS);
  void		_PG_init(void);
  
  static PerlInterpreter *plperl_init_interp(void);
  static void plperl_destroy_interp(PerlInterpreter **);
  static void plperl_fini(int code, Datum arg);
  static void set_interp_require(bool trusted);
  
  static Datum plperl_func_handler(PG_FUNCTION_ARGS);
  static Datum plperl_trigger_handler(PG_FUNCTION_ARGS);
  static void plperl_event_trigger_handler(PG_FUNCTION_ARGS);
  
  static void free_plperl_function(plperl_proc_desc *prodesc);
  
  static plperl_proc_desc *compile_plperl_function(Oid fn_oid,
  												 bool is_trigger,
  												 bool is_event_trigger);
  
  static SV  *plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc);
  static SV  *plperl_hash_from_datum(Datum attr);
  static SV  *plperl_ref_from_pg_array(Datum arg, Oid typid);
  static SV  *split_array(plperl_array_info *info, int first, int last, int nest);
  static SV  *make_array_ref(plperl_array_info *info, int first, int last);
  static SV  *get_perl_array_ref(SV *sv);
  static Datum plperl_sv_to_datum(SV *sv, Oid typid, int32 typmod,
  				   FunctionCallInfo fcinfo,
  				   FmgrInfo *finfo, Oid typioparam,
  				   bool *isnull);
  static void _sv_to_datum_finfo(Oid typid, FmgrInfo *finfo, Oid *typioparam);
  static Datum plperl_array_to_datum(SV *src, Oid typid, int32 typmod);
  static ArrayBuildState *array_to_datum_internal(AV *av, ArrayBuildState *astate,
  						int *ndims, int *dims, int cur_depth,
  						Oid arraytypid, Oid elemtypid, int32 typmod,
  						FmgrInfo *finfo, Oid typioparam);
  static Datum plperl_hash_to_datum(SV *src, TupleDesc td);
  
  static void plperl_init_shared_libs(pTHX);
  static void plperl_trusted_init(void);
  static void plperl_untrusted_init(void);
  static HV  *plperl_spi_execute_fetch_result(SPITupleTable *, int, int);
  static char *hek2cstr(HE *he);
  static SV **hv_store_string(HV *hv, const char *key, SV *val);
  static SV **hv_fetch_string(HV *hv, const char *key);
  static void plperl_create_sub(plperl_proc_desc *desc, char *s, Oid fn_oid);
  static SV  *plperl_call_perl_func(plperl_proc_desc *desc,
  					  FunctionCallInfo fcinfo);
  static void plperl_compile_callback(void *arg);
  static void plperl_exec_callback(void *arg);
  static void plperl_inline_callback(void *arg);
  static char *strip_trailing_ws(const char *msg);
  static OP  *pp_require_safe(pTHX);
  static void activate_interpreter(plperl_interp_desc *interp_desc);
  
  #ifdef WIN32
  static char *setlocale_perl(int category, char *locale);
  #endif
  
  /*
   * convert a HE (hash entry) key to a cstr in the current database encoding
   */
  static char *
  hek2cstr(HE *he)
  {
  	/*-------------------------
  	 * Unfortunately,  while HeUTF8 is true for most things > 256, for values
  	 * 128..255 it's not, but perl will treat them as unicode code points if
  	 * the utf8 flag is not set ( see The "Unicode Bug" in perldoc perlunicode
  	 * for more)
  	 *
  	 * So if we did the expected:
  	 *	  if (HeUTF8(he))
  	 *		  utf_u2e(key...);
  	 *	  else // must be ascii
  	 *		  return HePV(he);
  	 * we won't match columns with codepoints from 128..255
  	 *
  	 * For a more concrete example given a column with the name of the unicode
  	 * codepoint U+00ae (registered sign) and a UTF8 database and the perl
  	 * return_next { "\N{U+00ae}=>'text } would always fail as heUTF8 returns
  	 * 0 and HePV() would give us a char * with 1 byte contains the decimal
  	 * value 174
  	 *
  	 * Perl has the brains to know when it should utf8 encode 174 properly, so
  	 * here we force it into an SV so that perl will figure it out and do the
  	 * right thing
  	 *-------------------------
  	 */
  	SV		   *sv = HeSVKEY_force(he);
  
  	if (HeUTF8(he))
  		SvUTF8_on(sv);
  	return sv2cstr(sv);
  }
  
  /*
   * This routine is a crock, and so is everyplace that calls it.  The problem
   * is that the cached form of plperl functions/queries is allocated permanently
   * (mostly via malloc()) and never released until backend exit.  Subsidiary
   * data structures such as fmgr info records therefore must live forever
   * as well.  A better implementation would store all this stuff in a per-
   * function memory context that could be reclaimed at need.  In the meantime,
   * fmgr_info_cxt must be called specifying TopMemoryContext so that whatever
   * it might allocate, and whatever the eventual function might allocate using
   * fn_mcxt, will live forever too.
   */
  static void
  perm_fmgr_info(Oid functionId, FmgrInfo *finfo)
  {
  	fmgr_info_cxt(functionId, finfo, TopMemoryContext);
  }
  
  
  /*
   * _PG_init()			- library load-time initialization
   *
   * DO NOT make this static nor change its name!
   */
  void
  _PG_init(void)
  {
  	/*
  	 * Be sure we do initialization only once.
  	 *
  	 * If initialization fails due to, e.g., plperl_init_interp() throwing an
  	 * exception, then we'll return here on the next usage and the user will
  	 * get a rather cryptic: ERROR:  attempt to redefine parameter
  	 * "plperl.use_strict"
  	 */
  	static bool inited = false;
  	HASHCTL		hash_ctl;
  
  	if (inited)
  		return;
  
  	/*
  	 * Support localized messages.
  	 */
  	pg_bindtextdomain(TEXTDOMAIN);
  
  	/*
  	 * Initialize plperl's GUCs.
  	 */
  	DefineCustomBoolVariable("plperl.use_strict",
  							 gettext_noop("If true, trusted and untrusted Perl code will be compiled in strict mode."),
  							 NULL,
  							 &plperl_use_strict,
  							 false,
  							 PGC_USERSET, 0,
  							 NULL, NULL, NULL);
  
  	/*
  	 * plperl.on_init is marked PGC_SIGHUP to support the idea that it might
  	 * be executed in the postmaster (if plperl is loaded into the postmaster
  	 * via shared_preload_libraries).  This isn't really right either way,
  	 * though.
  	 */
  	DefineCustomStringVariable("plperl.on_init",
  							   gettext_noop("Perl initialization code to execute when a Perl interpreter is initialized."),
  							   NULL,
  							   &plperl_on_init,
  							   NULL,
  							   PGC_SIGHUP, 0,
  							   NULL, NULL, NULL);
  
  	/*
  	 * plperl.on_plperl_init is marked PGC_SUSET to avoid issues whereby a
  	 * user who might not even have USAGE privilege on the plperl language
  	 * could nonetheless use SET plperl.on_plperl_init='...' to influence the
  	 * behaviour of any existing plperl function that they can execute (which
  	 * might be SECURITY DEFINER, leading to a privilege escalation).  See
  	 * http://archives.postgresql.org/pgsql-hackers/2010-02/msg00281.php and
  	 * the overall thread.
  	 *
  	 * Note that because plperl.use_strict is USERSET, a nefarious user could
  	 * set it to be applied against other people's functions.  This is judged
  	 * OK since the worst result would be an error.  Your code oughta pass
  	 * use_strict anyway ;-)
  	 */
  	DefineCustomStringVariable("plperl.on_plperl_init",
  							   gettext_noop("Perl initialization code to execute once when plperl is first used."),
  							   NULL,
  							   &plperl_on_plperl_init,
  							   NULL,
  							   PGC_SUSET, 0,
  							   NULL, NULL, NULL);
  
  	DefineCustomStringVariable("plperl.on_plperlu_init",
  							   gettext_noop("Perl initialization code to execute once when plperlu is first used."),
  							   NULL,
  							   &plperl_on_plperlu_init,
  							   NULL,
  							   PGC_SUSET, 0,
  							   NULL, NULL, NULL);
  
  	EmitWarningsOnPlaceholders("plperl");
  
  	/*
  	 * Create hash tables.
  	 */
  	memset(&hash_ctl, 0, sizeof(hash_ctl));
  	hash_ctl.keysize = sizeof(Oid);
  	hash_ctl.entrysize = sizeof(plperl_interp_desc);
  	hash_ctl.hash = oid_hash;
  	plperl_interp_hash = hash_create("PL/Perl interpreters",
  									 8,
  									 &hash_ctl,
  									 HASH_ELEM | HASH_FUNCTION);
  
  	memset(&hash_ctl, 0, sizeof(hash_ctl));
  	hash_ctl.keysize = sizeof(plperl_proc_key);
  	hash_ctl.entrysize = sizeof(plperl_proc_ptr);
  	hash_ctl.hash = tag_hash;
  	plperl_proc_hash = hash_create("PL/Perl procedures",
  								   32,
  								   &hash_ctl,
  								   HASH_ELEM | HASH_FUNCTION);
  
  	/*
  	 * Save the default opmask.
  	 */
  	PLPERL_SET_OPMASK(plperl_opmask);
  
  	/*
  	 * Create the first Perl interpreter, but only partially initialize it.
  	 */
  	plperl_held_interp = plperl_init_interp();
  
  	inited = true;
  }
  
  
  static void
  set_interp_require(bool trusted)
  {
  	if (trusted)
  	{
  		PL_ppaddr[OP_REQUIRE] = pp_require_safe;
  		PL_ppaddr[OP_DOFILE] = pp_require_safe;
  	}
  	else
  	{
  		PL_ppaddr[OP_REQUIRE] = pp_require_orig;
  		PL_ppaddr[OP_DOFILE] = pp_require_orig;
  	}
  }
  
  /*
   * Cleanup perl interpreters, including running END blocks.
   * Does not fully undo the actions of _PG_init() nor make it callable again.
   */
  static void
  plperl_fini(int code, Datum arg)
  {
  	HASH_SEQ_STATUS hash_seq;
  	plperl_interp_desc *interp_desc;
  
  	elog(DEBUG3, "plperl_fini");
  
  	/*
  	 * Indicate that perl is terminating. Disables use of spi_* functions when
  	 * running END/DESTROY code. See check_spi_usage_allowed(). Could be
  	 * enabled in future, with care, using a transaction
  	 * http://archives.postgresql.org/pgsql-hackers/2010-01/msg02743.php
  	 */
  	plperl_ending = true;
  
  	/* Only perform perl cleanup if we're exiting cleanly */
  	if (code)
  	{
  		elog(DEBUG3, "plperl_fini: skipped");
  		return;
  	}
  
  	/* Zap the "held" interpreter, if we still have it */
  	plperl_destroy_interp(&plperl_held_interp);
  
  	/* Zap any fully-initialized interpreters */
  	hash_seq_init(&hash_seq, plperl_interp_hash);
  	while ((interp_desc = hash_seq_search(&hash_seq)) != NULL)
  	{
  		if (interp_desc->interp)
  		{
  			activate_interpreter(interp_desc);
  			plperl_destroy_interp(&interp_desc->interp);
  		}
  	}
  
  	elog(DEBUG3, "plperl_fini: done");
  }
  
  
  /*
   * Select and activate an appropriate Perl interpreter.
   */
  static void
  select_perl_context(bool trusted)
  {
  	Oid			user_id;
  	plperl_interp_desc *interp_desc;
  	bool		found;
  	PerlInterpreter *interp = NULL;
  
  	/* Find or create the interpreter hashtable entry for this userid */
  	if (trusted)
  		user_id = GetUserId();
  	else
  		user_id = InvalidOid;
  
  	interp_desc = hash_search(plperl_interp_hash, &user_id,
  							  HASH_ENTER,
  							  &found);
  	if (!found)
  	{
  		/* Initialize newly-created hashtable entry */
  		interp_desc->interp = NULL;
  		interp_desc->query_hash = NULL;
  	}
  
  	/* Make sure we have a query_hash for this interpreter */
  	if (interp_desc->query_hash == NULL)
  	{
  		HASHCTL		hash_ctl;
  
  		memset(&hash_ctl, 0, sizeof(hash_ctl));
  		hash_ctl.keysize = NAMEDATALEN;
  		hash_ctl.entrysize = sizeof(plperl_query_entry);
  		interp_desc->query_hash = hash_create("PL/Perl queries",
  											  32,
  											  &hash_ctl,
  											  HASH_ELEM);
  	}
  
  	/*
  	 * Quick exit if already have an interpreter
  	 */
  	if (interp_desc->interp)
  	{
  		activate_interpreter(interp_desc);
  		return;
  	}
  
  	/*
  	 * adopt held interp if free, else create new one if possible
  	 */
  	if (plperl_held_interp != NULL)
  	{
  		/* first actual use of a perl interpreter */
  		interp = plperl_held_interp;
  
  		/*
  		 * Reset the plperl_held_interp pointer first; if we fail during init
  		 * we don't want to try again with the partially-initialized interp.
  		 */
  		plperl_held_interp = NULL;
  
  		if (trusted)
  			plperl_trusted_init();
  		else
  			plperl_untrusted_init();
  
  		/* successfully initialized, so arrange for cleanup */
  		on_proc_exit(plperl_fini, 0);
  	}
  	else
  	{
  #ifdef MULTIPLICITY
  
  		/*
  		 * plperl_init_interp will change Perl's idea of the active
  		 * interpreter.  Reset plperl_active_interp temporarily, so that if we
  		 * hit an error partway through here, we'll make sure to switch back
  		 * to a non-broken interpreter before running any other Perl
  		 * functions.
  		 */
  		plperl_active_interp = NULL;
  
  		/* Now build the new interpreter */
  		interp = plperl_init_interp();
  
  		if (trusted)
  			plperl_trusted_init();
  		else
  			plperl_untrusted_init();
  #else
  		elog(ERROR,
  			 "cannot allocate multiple Perl interpreters on this platform");
  #endif
  	}
  
  	set_interp_require(trusted);
  
  	/*
  	 * Since the timing of first use of PL/Perl can't be predicted, any
  	 * database interaction during initialization is problematic. Including,
  	 * but not limited to, security definer issues. So we only enable access
  	 * to the database AFTER on_*_init code has run. See
  	 * http://archives.postgresql.org/pgsql-hackers/2010-01/msg02669.php
  	 */
  	newXS("PostgreSQL::InServer::SPI::bootstrap",
  		  boot_PostgreSQL__InServer__SPI, __FILE__);
  
  	eval_pv("PostgreSQL::InServer::SPI::bootstrap()", FALSE);
  	if (SvTRUE(ERRSV))
  		ereport(ERROR,
  				(errmsg("%s", strip_trailing_ws(sv2cstr(ERRSV))),
  		errcontext("while executing PostgreSQL::InServer::SPI::bootstrap")));
  
  	/* Fully initialized, so mark the hashtable entry valid */
  	interp_desc->interp = interp;
  
  	/* And mark this as the active interpreter */
  	plperl_active_interp = interp_desc;
  }
  
  /*
   * Make the specified interpreter the active one
   *
   * A call with NULL does nothing.  This is so that "restoring" to a previously
   * null state of plperl_active_interp doesn't result in useless thrashing.
   */
  static void
  activate_interpreter(plperl_interp_desc *interp_desc)
  {
  	if (interp_desc && plperl_active_interp != interp_desc)
  	{
  		Assert(interp_desc->interp);
  		PERL_SET_CONTEXT(interp_desc->interp);
  		/* trusted iff user_id isn't InvalidOid */
  		set_interp_require(OidIsValid(interp_desc->user_id));
  		plperl_active_interp = interp_desc;
  	}
  }
  
  /*
   * Create a new Perl interpreter.
   *
   * We initialize the interpreter as far as we can without knowing whether
   * it will become a trusted or untrusted interpreter; in particular, the
   * plperl.on_init code will get executed.  Later, either plperl_trusted_init
   * or plperl_untrusted_init must be called to complete the initialization.
   */
  static PerlInterpreter *
  plperl_init_interp(void)
  {
  	PerlInterpreter *plperl;
  
  	static char *embedding[3 + 2] = {
  		"", "-e", PLC_PERLBOOT
  	};
  	int			nargs = 3;
  
  #ifdef WIN32
  
  	/*
  	 * The perl library on startup does horrible things like call
  	 * setlocale(LC_ALL,""). We have protected against that on most platforms
  	 * by setting the environment appropriately. However, on Windows,
  	 * setlocale() does not consult the environment, so we need to save the
  	 * existing locale settings before perl has a chance to mangle them and
  	 * restore them after its dirty deeds are done.
  	 *
  	 * MSDN ref:
  	 * http://msdn.microsoft.com/library/en-us/vclib/html/_crt_locale.asp
  	 *
  	 * It appears that we only need to do this on interpreter startup, and
  	 * subsequent calls to the interpreter don't mess with the locale
  	 * settings.
  	 *
  	 * We restore them using setlocale_perl(), defined below, so that Perl
  	 * doesn't have a different idea of the locale from Postgres.
  	 *
  	 */
  
  	char	   *loc;
  	char	   *save_collate,
  			   *save_ctype,
  			   *save_monetary,
  			   *save_numeric,
  			   *save_time;
  
  	loc = setlocale(LC_COLLATE, NULL);
  	save_collate = loc ? pstrdup(loc) : NULL;
  	loc = setlocale(LC_CTYPE, NULL);
  	save_ctype = loc ? pstrdup(loc) : NULL;
  	loc = setlocale(LC_MONETARY, NULL);
  	save_monetary = loc ? pstrdup(loc) : NULL;
  	loc = setlocale(LC_NUMERIC, NULL);
  	save_numeric = loc ? pstrdup(loc) : NULL;
  	loc = setlocale(LC_TIME, NULL);
  	save_time = loc ? pstrdup(loc) : NULL;
  
  #define PLPERL_RESTORE_LOCALE(name, saved) \
  	STMT_START { \
  		if (saved != NULL) { setlocale_perl(name, saved); pfree(saved); } \
  	} STMT_END
  #endif   /* WIN32 */
  
  	if (plperl_on_init && *plperl_on_init)
  	{
  		embedding[nargs++] = "-e";
  		embedding[nargs++] = plperl_on_init;
  	}
  
  	/*
  	 * The perl API docs state that PERL_SYS_INIT3 should be called before
  	 * allocating interpreters. Unfortunately, on some platforms this fails in
  	 * the Perl_do_taint() routine, which is called when the platform is using
  	 * the system's malloc() instead of perl's own. Other platforms, notably
  	 * Windows, fail if PERL_SYS_INIT3 is not called. So we call it if it's
  	 * available, unless perl is using the system malloc(), which is true when
  	 * MYMALLOC is set.
  	 */
  #if defined(PERL_SYS_INIT3) && !defined(MYMALLOC)
  	{
  		static int	perl_sys_init_done;
  
  		/* only call this the first time through, as per perlembed man page */
  		if (!perl_sys_init_done)
  		{
  			char	   *dummy_env[1] = {NULL};
  
  			PERL_SYS_INIT3(&nargs, (char ***) &embedding, (char ***) &dummy_env);
  
  			/*
  			 * For unclear reasons, PERL_SYS_INIT3 sets the SIGFPE handler to
  			 * SIG_IGN.  Aside from being extremely unfriendly behavior for a
  			 * library, this is dumb on the grounds that the results of a
  			 * SIGFPE in this state are undefined according to POSIX, and in
  			 * fact you get a forced process kill at least on Linux.  Hence,
  			 * restore the SIGFPE handler to the backend's standard setting.
  			 * (See Perl bug 114574 for more information.)
  			 */
  			pqsignal(SIGFPE, FloatExceptionHandler);
  
  			perl_sys_init_done = 1;
  			/* quiet warning if PERL_SYS_INIT3 doesn't use the third argument */
  			dummy_env[0] = NULL;
  		}
  	}
  #endif
  
  	plperl = perl_alloc();
  	if (!plperl)
  		elog(ERROR, "could not allocate Perl interpreter");
  
  	PERL_SET_CONTEXT(plperl);
  	perl_construct(plperl);
  
  	/* run END blocks in perl_destruct instead of perl_run */
  	PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
  
  	/*
  	 * Record the original function for the 'require' and 'dofile' opcodes.
  	 * (They share the same implementation.) Ensure it's used for new
  	 * interpreters.
  	 */
  	if (!pp_require_orig)
  		pp_require_orig = PL_ppaddr[OP_REQUIRE];
  	else
  	{
  		PL_ppaddr[OP_REQUIRE] = pp_require_orig;
  		PL_ppaddr[OP_DOFILE] = pp_require_orig;
  	}
  
  #ifdef PLPERL_ENABLE_OPMASK_EARLY
  
  	/*
  	 * For regression testing to prove that the PLC_PERLBOOT and PLC_TRUSTED
  	 * code doesn't even compile any unsafe ops. In future there may be a
  	 * valid need for them to do so, in which case this could be softened
  	 * (perhaps moved to plperl_trusted_init()) or removed.
  	 */
  	PL_op_mask = plperl_opmask;
  #endif
  
  	if (perl_parse(plperl, plperl_init_shared_libs,
  				   nargs, embedding, NULL) != 0)
  		ereport(ERROR,
  				(errmsg("%s", strip_trailing_ws(sv2cstr(ERRSV))),
  				 errcontext("while parsing Perl initialization")));
  
  	if (perl_run(plperl) != 0)
  		ereport(ERROR,
  				(errmsg("%s", strip_trailing_ws(sv2cstr(ERRSV))),
  				 errcontext("while running Perl initialization")));
  
  #ifdef PLPERL_RESTORE_LOCALE
  	PLPERL_RESTORE_LOCALE(LC_COLLATE, save_collate);
  	PLPERL_RESTORE_LOCALE(LC_CTYPE, save_ctype);
  	PLPERL_RESTORE_LOCALE(LC_MONETARY, save_monetary);
  	PLPERL_RESTORE_LOCALE(LC_NUMERIC, save_numeric);
  	PLPERL_RESTORE_LOCALE(LC_TIME, save_time);
  #endif
  
  	return plperl;
  }
  
  
  /*
   * Our safe implementation of the require opcode.
   * This is safe because it's completely unable to load any code.
   * If the requested file/module has already been loaded it'll return true.
   * If not, it'll die.
   * So now "use Foo;" will work iff Foo has already been loaded.
   */
  static OP  *
  pp_require_safe(pTHX)
  {
  	dVAR;
  	dSP;
  	SV		   *sv,
  			  **svp;
  	char	   *name;
  	STRLEN		len;
  
  	sv = POPs;
  	name = SvPV(sv, len);
  	if (!(name && len > 0 && *name))
  		RETPUSHNO;
  
  	svp = hv_fetch(GvHVn(PL_incgv), name, len, 0);
  	if (svp && *svp != &PL_sv_undef)
  		RETPUSHYES;
  
  	DIE(aTHX_ "Unable to load %s into plperl", name);
  
  	/*
  	 * In most Perl versions, DIE() expands to a return statement, so the next
  	 * line is not necessary.  But in versions between but not including
  	 * 5.11.1 and 5.13.3 it does not, so the next line is necessary to avoid a
  	 * "control reaches end of non-void function" warning from gcc.  Other
  	 * compilers such as Solaris Studio will, however, issue a "statement not
  	 * reached" warning instead.
  	 */
  	return NULL;
  }
  
  
  /*
   * Destroy one Perl interpreter ... actually we just run END blocks.
   *
   * Caller must have ensured this interpreter is the active one.
   */
  static void
  plperl_destroy_interp(PerlInterpreter **interp)
  {
  	if (interp && *interp)
  	{
  		/*
  		 * Only a very minimal destruction is performed: - just call END
  		 * blocks.
  		 *
  		 * We could call perl_destruct() but we'd need to audit its actions
  		 * very carefully and work-around any that impact us. (Calling
  		 * sv_clean_objs() isn't an option because it's not part of perl's
  		 * public API so isn't portably available.) Meanwhile END blocks can
  		 * be used to perform manual cleanup.
  		 */
  
  		/* Run END blocks - based on perl's perl_destruct() */
  		if (PL_exit_flags & PERL_EXIT_DESTRUCT_END)
  		{
  			dJMPENV;
  			int			x = 0;
  
  			JMPENV_PUSH(x);
  			PERL_UNUSED_VAR(x);
  			if (PL_endav && !PL_minus_c)
  				call_list(PL_scopestack_ix, PL_endav);
  			JMPENV_POP;
  		}
  		LEAVE;
  		FREETMPS;
  
  		*interp = NULL;
  	}
  }
  
  /*
   * Initialize the current Perl interpreter as a trusted interp
   */
  static void
  plperl_trusted_init(void)
  {
  	HV		   *stash;
  	SV		   *sv;
  	char	   *key;
  	I32			klen;
  
  	/* use original require while we set up */
  	PL_ppaddr[OP_REQUIRE] = pp_require_orig;
  	PL_ppaddr[OP_DOFILE] = pp_require_orig;
  
  	eval_pv(PLC_TRUSTED, FALSE);
  	if (SvTRUE(ERRSV))
  		ereport(ERROR,
  				(errmsg("%s", strip_trailing_ws(sv2cstr(ERRSV))),
  				 errcontext("while executing PLC_TRUSTED")));
  
  	/*
  	 * Force loading of utf8 module now to prevent errors that can arise from
  	 * the regex code later trying to load utf8 modules. See
  	 * http://rt.perl.org/rt3/Ticket/Display.html?id=47576
  	 */
  	eval_pv("my $a=chr(0x100); return $a =~ /\\xa9/i", FALSE);
  	if (SvTRUE(ERRSV))
  		ereport(ERROR,
  				(errmsg("%s", strip_trailing_ws(sv2cstr(ERRSV))),
  				 errcontext("while executing utf8fix")));
  
  	/*
  	 * Lock down the interpreter
  	 */
  
  	/* switch to the safe require/dofile opcode for future code */
  	PL_ppaddr[OP_REQUIRE] = pp_require_safe;
  	PL_ppaddr[OP_DOFILE] = pp_require_safe;
  
  	/*
  	 * prevent (any more) unsafe opcodes being compiled PL_op_mask is per
  	 * interpreter, so this only needs to be set once
  	 */
  	PL_op_mask = plperl_opmask;
  
  	/* delete the DynaLoader:: namespace so extensions can't be loaded */
  	stash = gv_stashpv("DynaLoader", GV_ADDWARN);
  	hv_iterinit(stash);
  	while ((sv = hv_iternextsv(stash, &key, &klen)))
  	{
  		if (!isGV_with_GP(sv) || !GvCV(sv))
  			continue;
  		SvREFCNT_dec(GvCV(sv)); /* free the CV */
  		GvCV_set(sv, NULL);		/* prevent call via GV */
  	}
  	hv_clear(stash);
  
  	/* invalidate assorted caches */
  	++PL_sub_generation;
  	hv_clear(PL_stashcache);
  
  	/*
  	 * Execute plperl.on_plperl_init in the locked-down interpreter
  	 */
  	if (plperl_on_plperl_init && *plperl_on_plperl_init)
  	{
  		eval_pv(plperl_on_plperl_init, FALSE);
  		if (SvTRUE(ERRSV))
  			ereport(ERROR,
  					(errmsg("%s", strip_trailing_ws(sv2cstr(ERRSV))),
  					 errcontext("while executing plperl.on_plperl_init")));
  
  	}
  }
  
  
  /*
   * Initialize the current Perl interpreter as an untrusted interp
   */
  static void
  plperl_untrusted_init(void)
  {
  	/*
  	 * Nothing to do except execute plperl.on_plperlu_init
  	 */
  	if (plperl_on_plperlu_init && *plperl_on_plperlu_init)
  	{
  		eval_pv(plperl_on_plperlu_init, FALSE);
  		if (SvTRUE(ERRSV))
  			ereport(ERROR,
  					(errmsg("%s", strip_trailing_ws(sv2cstr(ERRSV))),
  					 errcontext("while executing plperl.on_plperlu_init")));
  	}
  }
  
  
  /*
   * Perl likes to put a newline after its error messages; clean up such
   */
  static char *
  strip_trailing_ws(const char *msg)
  {
  	char	   *res = pstrdup(msg);
  	int			len = strlen(res);
  
  	while (len > 0 && isspace((unsigned char) res[len - 1]))
  		res[--len] = '\0';
  	return res;
  }
  
  
  /* Build a tuple from a hash. */
  
  static HeapTuple
  plperl_build_tuple_result(HV *perlhash, TupleDesc td)
  {
  	Datum	   *values;
  	bool	   *nulls;
  	HE		   *he;
  	HeapTuple	tup;
  
  	values = palloc0(sizeof(Datum) * td->natts);
  	nulls = palloc(sizeof(bool) * td->natts);
  	memset(nulls, true, sizeof(bool) * td->natts);
  
  	hv_iterinit(perlhash);
  	while ((he = hv_iternext(perlhash)))
  	{
  		SV		   *val = HeVAL(he);
  		char	   *key = hek2cstr(he);
  		int			attn = SPI_fnumber(td, key);
  
  		if (attn <= 0 || td->attrs[attn - 1]->attisdropped)
  			ereport(ERROR,
  					(errcode(ERRCODE_UNDEFINED_COLUMN),
  					 errmsg("Perl hash contains nonexistent column \"%s\"",
  							key)));
  
  		values[attn - 1] = plperl_sv_to_datum(val,
  											  td->attrs[attn - 1]->atttypid,
  											  td->attrs[attn - 1]->atttypmod,
  											  NULL,
  											  NULL,
  											  InvalidOid,
  											  &nulls[attn - 1]);
  
  		pfree(key);
  	}
  	hv_iterinit(perlhash);
  
  	tup = heap_form_tuple(td, values, nulls);
  	pfree(values);
  	pfree(nulls);
  	return tup;
  }
  
  /* convert a hash reference to a datum */
  static Datum
  plperl_hash_to_datum(SV *src, TupleDesc td)
  {
  	HeapTuple	tup = plperl_build_tuple_result((HV *) SvRV(src), td);
  
  	return HeapTupleGetDatum(tup);
  }
  
  /*
   * if we are an array ref return the reference. this is special in that if we
   * are a PostgreSQL::InServer::ARRAY object we will return the 'magic' array.
   */
  static SV  *
  get_perl_array_ref(SV *sv)
  {
  	if (SvOK(sv) && SvROK(sv))
  	{
  		if (SvTYPE(SvRV(sv)) == SVt_PVAV)
  			return sv;
  		else if (sv_isa(sv, "PostgreSQL::InServer::ARRAY"))
  		{
  			HV		   *hv = (HV *) SvRV(sv);
  			SV		  **sav = hv_fetch_string(hv, "array");
  
  			if (*sav && SvOK(*sav) && SvROK(*sav) &&
  				SvTYPE(SvRV(*sav)) == SVt_PVAV)
  				return *sav;
  
  			elog(ERROR, "could not get array reference from PostgreSQL::InServer::ARRAY object");
  		}
  	}
  	return NULL;
  }
  
  /*
   * helper function for plperl_array_to_datum, recurses for multi-D arrays
   */
  static ArrayBuildState *
  array_to_datum_internal(AV *av, ArrayBuildState *astate,
  						int *ndims, int *dims, int cur_depth,
  						Oid arraytypid, Oid elemtypid, int32 typmod,
  						FmgrInfo *finfo, Oid typioparam)
  {
  	int			i;
  	int			len = av_len(av) + 1;
  
  	for (i = 0; i < len; i++)
  	{
  		/* fetch the array element */
  		SV		  **svp = av_fetch(av, i, FALSE);
  
  		/* see if this element is an array, if so get that */
  		SV		   *sav = svp ? get_perl_array_ref(*svp) : NULL;
  
  		/* multi-dimensional array? */
  		if (sav)
  		{
  			AV		   *nav = (AV *) SvRV(sav);
  
  			/* dimensionality checks */
  			if (cur_depth + 1 > MAXDIM)
  				ereport(ERROR,
  						(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
  						 errmsg("number of array dimensions (%d) exceeds the maximum allowed (%d)",
  								cur_depth + 1, MAXDIM)));
  
  			/* set size when at first element in this level, else compare */
  			if (i == 0 && *ndims == cur_depth)
  			{
  				dims[*ndims] = av_len(nav) + 1;
  				(*ndims)++;
  			}
  			else if (av_len(nav) + 1 != dims[cur_depth])
  				ereport(ERROR,
  						(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
  						 errmsg("multidimensional arrays must have array expressions with matching dimensions")));
  
  			/* recurse to fetch elements of this sub-array */
  			astate = array_to_datum_internal(nav, astate,
  											 ndims, dims, cur_depth + 1,
  											 arraytypid, elemtypid, typmod,
  											 finfo, typioparam);
  		}
  		else
  		{
  			Datum		dat;
  			bool		isnull;
  
  			/* scalar after some sub-arrays at same level? */
  			if (*ndims != cur_depth)
  				ereport(ERROR,
  						(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
  						 errmsg("multidimensional arrays must have array expressions with matching dimensions")));
  
  			dat = plperl_sv_to_datum(svp ? *svp : NULL,
  									 elemtypid,
  									 typmod,
  									 NULL,
  									 finfo,
  									 typioparam,
  									 &isnull);
  
  			astate = accumArrayResult(astate, dat, isnull,
  									  elemtypid, CurrentMemoryContext);
  		}
  	}
  
  	return astate;
  }
  
  /*
   * convert perl array ref to a datum
   */
  static Datum
  plperl_array_to_datum(SV *src, Oid typid, int32 typmod)
  {
  	ArrayBuildState *astate;
  	Oid			elemtypid;
  	FmgrInfo	finfo;
  	Oid			typioparam;
  	int			dims[MAXDIM];
  	int			lbs[MAXDIM];
  	int			ndims = 1;
  	int			i;
  
  	elemtypid = get_element_type(typid);
  	if (!elemtypid)
  		ereport(ERROR,
  				(errcode(ERRCODE_DATATYPE_MISMATCH),
  				 errmsg("cannot convert Perl array to non-array type %s",
  						format_type_be(typid))));
  
  	_sv_to_datum_finfo(elemtypid, &finfo, &typioparam);
  
  	memset(dims, 0, sizeof(dims));
  	dims[0] = av_len((AV *) SvRV(src)) + 1;
  
  	astate = array_to_datum_internal((AV *) SvRV(src), NULL,
  									 &ndims, dims, 1,
  									 typid, elemtypid, typmod,
  									 &finfo, typioparam);
  
  	if (!astate)
  		return PointerGetDatum(construct_empty_array(elemtypid));
  
  	for (i = 0; i < ndims; i++)
  		lbs[i] = 1;
  
  	return makeMdArrayResult(astate, ndims, dims, lbs,
  							 CurrentMemoryContext, true);
  }
  
  /* Get the information needed to convert data to the specified PG type */
  static void
  _sv_to_datum_finfo(Oid typid, FmgrInfo *finfo, Oid *typioparam)
  {
  	Oid			typinput;
  
  	/* XXX would be better to cache these lookups */
  	getTypeInputInfo(typid,
  					 &typinput, typioparam);
  	fmgr_info(typinput, finfo);
  }
  
  /*
   * convert Perl SV to PG datum of type typid, typmod typmod
   *
   * Pass the PL/Perl function's fcinfo when attempting to convert to the
   * function's result type; otherwise pass NULL.  This is used when we need to
   * resolve the actual result type of a function returning RECORD.
   *
   * finfo and typioparam should be the results of _sv_to_datum_finfo for the
   * given typid, or NULL/InvalidOid to let this function do the lookups.
   *
   * *isnull is an output parameter.
   */
  static Datum
  plperl_sv_to_datum(SV *sv, Oid typid, int32 typmod,
  				   FunctionCallInfo fcinfo,
  				   FmgrInfo *finfo, Oid typioparam,
  				   bool *isnull)
  {
  	FmgrInfo	tmp;
  
  	/* we might recurse */
  	check_stack_depth();
  
  	*isnull = false;
  
  	/*
  	 * Return NULL if result is undef, or if we're in a function returning
  	 * VOID.  In the latter case, we should pay no attention to the last Perl
  	 * statement's result, and this is a convenient means to ensure that.
  	 */
  	if (!sv || !SvOK(sv) || typid == VOIDOID)
  	{
  		/* look up type info if they did not pass it */
  		if (!finfo)
  		{
  			_sv_to_datum_finfo(typid, &tmp, &typioparam);
  			finfo = &tmp;
  		}
  		*isnull = true;
  		/* must call typinput in case it wants to reject NULL */
  		return InputFunctionCall(finfo, NULL, typioparam, typmod);
  	}
  	else if (SvROK(sv))
  	{
  		/* handle references */
  		SV		   *sav = get_perl_array_ref(sv);
  
  		if (sav)
  		{
  			/* handle an arrayref */
  			return plperl_array_to_datum(sav, typid, typmod);
  		}
  		else if (SvTYPE(SvRV(sv)) == SVt_PVHV)
  		{
  			/* handle a hashref */
  			Datum		ret;
  			TupleDesc	td;
  
  			if (!type_is_rowtype(typid))
  				ereport(ERROR,
  						(errcode(ERRCODE_DATATYPE_MISMATCH),
  				  errmsg("cannot convert Perl hash to non-composite type %s",
  						 format_type_be(typid))));
  
  			td = lookup_rowtype_tupdesc_noerror(typid, typmod, true);
  			if (td == NULL)
  			{
  				/* Try to look it up based on our result type */
  				if (fcinfo == NULL ||
  				get_call_result_type(fcinfo, NULL, &td) != TYPEFUNC_COMPOSITE)
  					ereport(ERROR,
  							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  						errmsg("function returning record called in context "
  							   "that cannot accept type record")));
  			}
  
  			ret = plperl_hash_to_datum(sv, td);
  
  			/* Release on the result of get_call_result_type is harmless */
  			ReleaseTupleDesc(td);
  
  			return ret;
  		}
  
  		/* Reference, but not reference to hash or array ... */
  		ereport(ERROR,
  				(errcode(ERRCODE_DATATYPE_MISMATCH),
  		 errmsg("PL/Perl function must return reference to hash or array")));
  		return (Datum) 0;		/* shut up compiler */
  	}
  	else
  	{
  		/* handle a string/number */
  		Datum		ret;
  		char	   *str = sv2cstr(sv);
  
  		/* did not pass in any typeinfo? look it up */
  		if (!finfo)
  		{
  			_sv_to_datum_finfo(typid, &tmp, &typioparam);
  			finfo = &tmp;
  		}
  
  		ret = InputFunctionCall(finfo, str, typioparam, typmod);
  		pfree(str);
  
  		return ret;
  	}
  }
  
  /* Convert the perl SV to a string returned by the type output function */
  char *
  plperl_sv_to_literal(SV *sv, char *fqtypename)
  {
  	Datum		str = CStringGetDatum(fqtypename);
  	Oid			typid = DirectFunctionCall1(regtypein, str);
  	Oid			typoutput;
  	Datum		datum;
  	bool		typisvarlena,
  				isnull;
  
  	if (!OidIsValid(typid))
  		elog(ERROR, "lookup failed for type %s", fqtypename);
  
  	datum = plperl_sv_to_datum(sv,
  							   typid, -1,
  							   NULL, NULL, InvalidOid,
  							   &isnull);
  
  	if (isnull)
  		return NULL;
  
  	getTypeOutputInfo(typid,
  					  &typoutput, &typisvarlena);
  
  	return OidOutputFunctionCall(typoutput, datum);
  }
  
  /*
   * Convert PostgreSQL array datum to a perl array reference.
   *
   * typid is arg's OID, which must be an array type.
   */
  static SV  *
  plperl_ref_from_pg_array(Datum arg, Oid typid)
  {
  	ArrayType  *ar = DatumGetArrayTypeP(arg);
  	Oid			elementtype = ARR_ELEMTYPE(ar);
  	int16		typlen;
  	bool		typbyval;
  	char		typalign,
  				typdelim;
  	Oid			typioparam;
  	Oid			typoutputfunc;
  	int			i,
  				nitems,
  			   *dims;
  	plperl_array_info *info;
  	SV		   *av;
  	HV		   *hv;
  
  	info = palloc(sizeof(plperl_array_info));
  
  	/* get element type information, including output conversion function */
  	get_type_io_data(elementtype, IOFunc_output,
  					 &typlen, &typbyval, &typalign,
  					 &typdelim, &typioparam, &typoutputfunc);
  
  	perm_fmgr_info(typoutputfunc, &info->proc);
  
  	info->elem_is_rowtype = type_is_rowtype(elementtype);
  
  	/* Get the number and bounds of array dimensions */
  	info->ndims = ARR_NDIM(ar);
  	dims = ARR_DIMS(ar);
  
  	deconstruct_array(ar, elementtype, typlen, typbyval,
  					  typalign, &info->elements, &info->nulls,
  					  &nitems);
  
  	/* Get total number of elements in each dimension */
  	info->nelems = palloc(sizeof(int) * info->ndims);
  	info->nelems[0] = nitems;
  	for (i = 1; i < info->ndims; i++)
  		info->nelems[i] = info->nelems[i - 1] / dims[i - 1];
  
  	av = split_array(info, 0, nitems, 0);
  
  	hv = newHV();
  	(void) hv_store(hv, "array", 5, av, 0);
  	(void) hv_store(hv, "typeoid", 7, newSViv(typid), 0);
  
  	return sv_bless(newRV_noinc((SV *) hv),
  					gv_stashpv("PostgreSQL::InServer::ARRAY", 0));
  }
  
  /*
   * Recursively form array references from splices of the initial array
   */
  static SV  *
  split_array(plperl_array_info *info, int first, int last, int nest)
  {
  	int			i;
  	AV		   *result;
  
  	/* since this function recurses, it could be driven to stack overflow */
  	check_stack_depth();
  
  	/*
  	 * Base case, return a reference to a single-dimensional array
  	 */
  	if (nest >= info->ndims - 1)
  		return make_array_ref(info, first, last);
  
  	result = newAV();
  	for (i = first; i < last; i += info->nelems[nest + 1])
  	{
  		/* Recursively form references to arrays of lower dimensions */
  		SV		   *ref = split_array(info, i, i + info->nelems[nest + 1], nest + 1);
  
  		av_push(result, ref);
  	}
  	return newRV_noinc((SV *) result);
  }
  
  /*
   * Create a Perl reference from a one-dimensional C array, converting
   * composite type elements to hash references.
   */
  static SV  *
  make_array_ref(plperl_array_info *info, int first, int last)
  {
  	int			i;
  	AV		   *result = newAV();
  
  	for (i = first; i < last; i++)
  	{
  		if (info->nulls[i])
  		{
  			/*
  			 * We can't use &PL_sv_undef here.  See "AVs, HVs and undefined
  			 * values" in perlguts.
  			 */
  			av_push(result, newSV(0));
  		}
  		else
  		{
  			Datum		itemvalue = info->elements[i];
  
  			/* Handle composite type elements */
  			if (info->elem_is_rowtype)
  				av_push(result, plperl_hash_from_datum(itemvalue));
  			else
  			{
  				char	   *val = OutputFunctionCall(&info->proc, itemvalue);
  
  				av_push(result, cstr2sv(val));
  			}
  		}
  	}
  	return newRV_noinc((SV *) result);
  }
  
  /* Set up the arguments for a trigger call. */
  static SV  *
  plperl_trigger_build_args(FunctionCallInfo fcinfo)
  {
  	TriggerData *tdata;
  	TupleDesc	tupdesc;
  	int			i;
  	char	   *level;
  	char	   *event;
  	char	   *relid;
  	char	   *when;
  	HV		   *hv;
  
  	hv = newHV();
  	hv_ksplit(hv, 12);			/* pre-grow the hash */
  
  	tdata = (TriggerData *) fcinfo->context;
  	tupdesc = tdata->tg_relation->rd_att;
  
  	relid = DatumGetCString(
  							DirectFunctionCall1(oidout,
  								  ObjectIdGetDatum(tdata->tg_relation->rd_id)
  												)
  		);
  
  	hv_store_string(hv, "name", cstr2sv(tdata->tg_trigger->tgname));
  	hv_store_string(hv, "relid", cstr2sv(relid));
  
  	if (TRIGGER_FIRED_BY_INSERT(tdata->tg_event))
  	{
  		event = "INSERT";
  		if (TRIGGER_FIRED_FOR_ROW(tdata->tg_event))
  			hv_store_string(hv, "new",
  							plperl_hash_from_tuple(tdata->tg_trigtuple,
  												   tupdesc));
  	}
  	else if (TRIGGER_FIRED_BY_DELETE(tdata->tg_event))
  	{
  		event = "DELETE";
  		if (TRIGGER_FIRED_FOR_ROW(tdata->tg_event))
  			hv_store_string(hv, "old",
  							plperl_hash_from_tuple(tdata->tg_trigtuple,
  												   tupdesc));
  	}
  	else if (TRIGGER_FIRED_BY_UPDATE(tdata->tg_event))
  	{
  		event = "UPDATE";
  		if (TRIGGER_FIRED_FOR_ROW(tdata->tg_event))
  		{
  			hv_store_string(hv, "old",
  							plperl_hash_from_tuple(tdata->tg_trigtuple,
  												   tupdesc));
  			hv_store_string(hv, "new",
  							plperl_hash_from_tuple(tdata->tg_newtuple,
  												   tupdesc));
  		}
  	}
  	else if (TRIGGER_FIRED_BY_TRUNCATE(tdata->tg_event))
  		event = "TRUNCATE";
  	else
  		event = "UNKNOWN";
  
  	hv_store_string(hv, "event", cstr2sv(event));
  	hv_store_string(hv, "argc", newSViv(tdata->tg_trigger->tgnargs));
  
  	if (tdata->tg_trigger->tgnargs > 0)
  	{
  		AV		   *av = newAV();
  
  		av_extend(av, tdata->tg_trigger->tgnargs);
  		for (i = 0; i < tdata->tg_trigger->tgnargs; i++)
  			av_push(av, cstr2sv(tdata->tg_trigger->tgargs[i]));
  		hv_store_string(hv, "args", newRV_noinc((SV *) av));
  	}
  
  	hv_store_string(hv, "relname",
  					cstr2sv(SPI_getrelname(tdata->tg_relation)));
  
  	hv_store_string(hv, "table_name",
  					cstr2sv(SPI_getrelname(tdata->tg_relation)));
  
  	hv_store_string(hv, "table_schema",
  					cstr2sv(SPI_getnspname(tdata->tg_relation)));
  
  	if (TRIGGER_FIRED_BEFORE(tdata->tg_event))
  		when = "BEFORE";
  	else if (TRIGGER_FIRED_AFTER(tdata->tg_event))
  		when = "AFTER";
  	else if (TRIGGER_FIRED_INSTEAD(tdata->tg_event))
  		when = "INSTEAD OF";
  	else
  		when = "UNKNOWN";
  	hv_store_string(hv, "when", cstr2sv(when));
  
  	if (TRIGGER_FIRED_FOR_ROW(tdata->tg_event))
  		level = "ROW";
  	else if (TRIGGER_FIRED_FOR_STATEMENT(tdata->tg_event))
  		level = "STATEMENT";
  	else
  		level = "UNKNOWN";
  	hv_store_string(hv, "level", cstr2sv(level));
  
  	return newRV_noinc((SV *) hv);
  }
  
  
  /* Set up the arguments for an event trigger call. */
  static SV  *
  plperl_event_trigger_build_args(FunctionCallInfo fcinfo)
  {
  	EventTriggerData *tdata;
  	HV		   *hv;
  
  	hv = newHV();
  
  	tdata = (EventTriggerData *) fcinfo->context;
  
  	hv_store_string(hv, "event", cstr2sv(tdata->event));
  	hv_store_string(hv, "tag", cstr2sv(tdata->tag));
  
  	return newRV_noinc((SV *) hv);
  }
  
  /* Set up the new tuple returned from a trigger. */
  
  static HeapTuple
  plperl_modify_tuple(HV *hvTD, TriggerData *tdata, HeapTuple otup)
  {
  	SV		  **svp;
  	HV		   *hvNew;
  	HE		   *he;
  	HeapTuple	rtup;
  	int			slotsused;
  	int		   *modattrs;
  	Datum	   *modvalues;
  	char	   *modnulls;
  
  	TupleDesc	tupdesc;
  
  	tupdesc = tdata->tg_relation->rd_att;
  
  	svp = hv_fetch_string(hvTD, "new");
  	if (!svp)
  		ereport(ERROR,
  				(errcode(ERRCODE_UNDEFINED_COLUMN),
  				 errmsg("$_TD->{new} does not exist")));
  	if (!SvOK(*svp) || !SvROK(*svp) || SvTYPE(SvRV(*svp)) != SVt_PVHV)
  		ereport(ERROR,
  				(errcode(ERRCODE_DATATYPE_MISMATCH),
  				 errmsg("$_TD->{new} is not a hash reference")));
  	hvNew = (HV *) SvRV(*svp);
  
  	modattrs = palloc(tupdesc->natts * sizeof(int));
  	modvalues = palloc(tupdesc->natts * sizeof(Datum));
  	modnulls = palloc(tupdesc->natts * sizeof(char));
  	slotsused = 0;
  
  	hv_iterinit(hvNew);
  	while ((he = hv_iternext(hvNew)))
  	{
  		bool		isnull;
  		char	   *key = hek2cstr(he);
  		SV		   *val = HeVAL(he);
  		int			attn = SPI_fnumber(tupdesc, key);
  
  		if (attn <= 0 || tupdesc->attrs[attn - 1]->attisdropped)
  			ereport(ERROR,
  					(errcode(ERRCODE_UNDEFINED_COLUMN),
  					 errmsg("Perl hash contains nonexistent column \"%s\"",
  							key)));
  
  		modvalues[slotsused] = plperl_sv_to_datum(val,
  										  tupdesc->attrs[attn - 1]->atttypid,
  										 tupdesc->attrs[attn - 1]->atttypmod,
  												  NULL,
  												  NULL,
  												  InvalidOid,
  												  &isnull);
  
  		modnulls[slotsused] = isnull ? 'n' : ' ';
  		modattrs[slotsused] = attn;
  		slotsused++;
  
  		pfree(key);
  	}
  	hv_iterinit(hvNew);
  
  	rtup = SPI_modifytuple(tdata->tg_relation, otup, slotsused,
  						   modattrs, modvalues, modnulls);
  
  	pfree(modattrs);
  	pfree(modvalues);
  	pfree(modnulls);
  
  	if (rtup == NULL)
  		elog(ERROR, "SPI_modifytuple failed: %s",
  			 SPI_result_code_string(SPI_result));
  
  	return rtup;
  }
  
  
  /*
   * There are three externally visible pieces to plperl: plperl_call_handler,
   * plperl_inline_handler, and plperl_validator.
   */
  
  /*
   * The call handler is called to run normal functions (including trigger
   * functions) that are defined in pg_proc.
   */
  PG_FUNCTION_INFO_V1(plperl_call_handler);
  
  Datum
  plperl_call_handler(PG_FUNCTION_ARGS)
  {
  	Datum		retval;
  	plperl_call_data *save_call_data = current_call_data;
  	plperl_interp_desc *oldinterp = plperl_active_interp;
  	plperl_call_data this_call_data;
  
  	/* Initialize current-call status record */
  	MemSet(&this_call_data, 0, sizeof(this_call_data));
  	this_call_data.fcinfo = fcinfo;
  
  	PG_TRY();
  	{
  		current_call_data = &this_call_data;
  		if (CALLED_AS_TRIGGER(fcinfo))
  			retval = PointerGetDatum(plperl_trigger_handler(fcinfo));
  		else if (CALLED_AS_EVENT_TRIGGER(fcinfo))
  		{
  			plperl_event_trigger_handler(fcinfo);
  			retval = (Datum) 0;
  		}
  		else
  			retval = plperl_func_handler(fcinfo);
  	}
  	PG_CATCH();
  	{
  		if (this_call_data.prodesc)
  			decrement_prodesc_refcount(this_call_data.prodesc);
  		current_call_data = save_call_data;
  		activate_interpreter(oldinterp);
  		PG_RE_THROW();
  	}
  	PG_END_TRY();
  
  	if (this_call_data.prodesc)
  		decrement_prodesc_refcount(this_call_data.prodesc);
  	current_call_data = save_call_data;
  	activate_interpreter(oldinterp);
  	return retval;
  }
  
  /*
   * The inline handler runs anonymous code blocks (DO blocks).
   */
  PG_FUNCTION_INFO_V1(plperl_inline_handler);
  
  Datum
  plperl_inline_handler(PG_FUNCTION_ARGS)
  {
  	InlineCodeBlock *codeblock = (InlineCodeBlock *) PG_GETARG_POINTER(0);
  	FunctionCallInfoData fake_fcinfo;
  	FmgrInfo	flinfo;
  	plperl_proc_desc desc;
  	plperl_call_data *save_call_data = current_call_data;
  	plperl_interp_desc *oldinterp = plperl_active_interp;
  	plperl_call_data this_call_data;
  	ErrorContextCallback pl_error_context;
  
  	/* Initialize current-call status record */
  	MemSet(&this_call_data, 0, sizeof(this_call_data));
  
  	/* Set up a callback for error reporting */
  	pl_error_context.callback = plperl_inline_callback;
  	pl_error_context.previous = error_context_stack;
  	pl_error_context.arg = (Datum) 0;
  	error_context_stack = &pl_error_context;
  
  	/*
  	 * Set up a fake fcinfo and descriptor with just enough info to satisfy
  	 * plperl_call_perl_func().  In particular note that this sets things up
  	 * with no arguments passed, and a result type of VOID.
  	 */
  	MemSet(&fake_fcinfo, 0, sizeof(fake_fcinfo));
  	MemSet(&flinfo, 0, sizeof(flinfo));
  	MemSet(&desc, 0, sizeof(desc));
  	fake_fcinfo.flinfo = &flinfo;
  	flinfo.fn_oid = InvalidOid;
  	flinfo.fn_mcxt = CurrentMemoryContext;
  
  	desc.proname = "inline_code_block";
  	desc.fn_readonly = false;
  
  	desc.lanpltrusted = codeblock->langIsTrusted;
  
  	desc.fn_retistuple = false;
  	desc.fn_retisset = false;
  	desc.fn_retisarray = false;
  	desc.result_oid = VOIDOID;
  	desc.nargs = 0;
  	desc.reference = NULL;
  
  	this_call_data.fcinfo = &fake_fcinfo;
  	this_call_data.prodesc = &desc;
  	/* we do not bother with refcounting the fake prodesc */
  
  	PG_TRY();
  	{
  		SV		   *perlret;
  
  		current_call_data = &this_call_data;
  
  		if (SPI_connect() != SPI_OK_CONNECT)
  			elog(ERROR, "could not connect to SPI manager");
  
  		select_perl_context(desc.lanpltrusted);
  
  		plperl_create_sub(&desc, codeblock->source_text, 0);
  
  		if (!desc.reference)	/* can this happen? */
  			elog(ERROR, "could not create internal procedure for anonymous code block");
  
  		perlret = plperl_call_perl_func(&desc, &fake_fcinfo);
  
  		SvREFCNT_dec(perlret);
  
  		if (SPI_finish() != SPI_OK_FINISH)
  			elog(ERROR, "SPI_finish() failed");
  	}
  	PG_CATCH();
  	{
  		if (desc.reference)
  			SvREFCNT_dec(desc.reference);
  		current_call_data = save_call_data;
  		activate_interpreter(oldinterp);
  		PG_RE_THROW();
  	}
  	PG_END_TRY();
  
  	if (desc.reference)
  		SvREFCNT_dec(desc.reference);
  
  	current_call_data = save_call_data;
  	activate_interpreter(oldinterp);
  
  	error_context_stack = pl_error_context.previous;
  
  	PG_RETURN_VOID();
  }
  
  /*
   * The validator is called during CREATE FUNCTION to validate the function
   * being created/replaced. The precise behavior of the validator may be
   * modified by the check_function_bodies GUC.
   */
  PG_FUNCTION_INFO_V1(plperl_validator);
  
  Datum
  plperl_validator(PG_FUNCTION_ARGS)
  {
  	Oid			funcoid = PG_GETARG_OID(0);
  	HeapTuple	tuple;
  	Form_pg_proc proc;
  	char		functyptype;
  	int			numargs;
  	Oid		   *argtypes;
  	char	  **argnames;
  	char	   *argmodes;
  	bool		is_trigger = false;
  	bool		is_event_trigger = false;
  	int			i;
  
  	/* Get the new function's pg_proc entry */
  	tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcoid));
  	if (!HeapTupleIsValid(tuple))
  		elog(ERROR, "cache lookup failed for function %u", funcoid);
  	proc = (Form_pg_proc) GETSTRUCT(tuple);
  
  	functyptype = get_typtype(proc->prorettype);
  
  	/* Disallow pseudotype result */
  	/* except for TRIGGER, EVTTRIGGER, RECORD, or VOID */
  	if (functyptype == TYPTYPE_PSEUDO)
  	{
  		/* we assume OPAQUE with no arguments means a trigger */
  		if (proc->prorettype == TRIGGEROID ||
  			(proc->prorettype == OPAQUEOID && proc->pronargs == 0))
  			is_trigger = true;
  		else if (proc->prorettype == EVTTRIGGEROID)
  			is_event_trigger = true;
  		else if (proc->prorettype != RECORDOID &&
  				 proc->prorettype != VOIDOID)
  			ereport(ERROR,
  					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  					 errmsg("PL/Perl functions cannot return type %s",
  							format_type_be(proc->prorettype))));
  	}
  
  	/* Disallow pseudotypes in arguments (either IN or OUT) */
  	numargs = get_func_arg_info(tuple,
  								&argtypes, &argnames, &argmodes);
  	for (i = 0; i < numargs; i++)
  	{
  		if (get_typtype(argtypes[i]) == TYPTYPE_PSEUDO &&
  			argtypes[i] != RECORDOID)
  			ereport(ERROR,
  					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  					 errmsg("PL/Perl functions cannot accept type %s",
  							format_type_be(argtypes[i]))));
  	}
  
  	ReleaseSysCache(tuple);
  
  	/* Postpone body checks if !check_function_bodies */
  	if (check_function_bodies)
  	{
  		(void) compile_plperl_function(funcoid, is_trigger, is_event_trigger);
  	}
  
  	/* the result of a validator is ignored */
  	PG_RETURN_VOID();
  }
  
  
  /*
   * plperlu likewise requires three externally visible functions:
   * plperlu_call_handler, plperlu_inline_handler, and plperlu_validator.
   * These are currently just aliases that send control to the plperl
   * handler functions, and we decide whether a particular function is
   * trusted or not by inspecting the actual pg_language tuple.
   */
  
  PG_FUNCTION_INFO_V1(plperlu_call_handler);
  
  Datum
  plperlu_call_handler(PG_FUNCTION_ARGS)
  {
  	return plperl_call_handler(fcinfo);
  }
  
  PG_FUNCTION_INFO_V1(plperlu_inline_handler);
  
  Datum
  plperlu_inline_handler(PG_FUNCTION_ARGS)
  {
  	return plperl_inline_handler(fcinfo);
  }
  
  PG_FUNCTION_INFO_V1(plperlu_validator);
  
  Datum
  plperlu_validator(PG_FUNCTION_ARGS)
  {
  	return plperl_validator(fcinfo);
  }
  
  
  /*
   * Uses mksafefunc/mkunsafefunc to create a subroutine whose text is
   * supplied in s, and returns a reference to it
   */
  static void
  plperl_create_sub(plperl_proc_desc *prodesc, char *s, Oid fn_oid)
  {
  	dSP;
  	char		subname[NAMEDATALEN + 40];
  	HV		   *pragma_hv = newHV();
  	SV		   *subref = NULL;
  	int			count;
  
  	sprintf(subname, "%s__%u", prodesc->proname, fn_oid);
  
  	if (plperl_use_strict)
  		hv_store_string(pragma_hv, "strict", (SV *) newAV());
  
  	ENTER;
  	SAVETMPS;
  	PUSHMARK(SP);
  	EXTEND(SP, 4);
  	PUSHs(sv_2mortal(cstr2sv(subname)));
  	PUSHs(sv_2mortal(newRV_noinc((SV *) pragma_hv)));
  
  	/*
  	 * Use 'false' for $prolog in mkfunc, which is kept for compatibility in
  	 * case a module such as PostgreSQL::PLPerl::NYTprof replaces the function
  	 * compiler.
  	 */
  	PUSHs(&PL_sv_no);
  	PUSHs(sv_2mortal(cstr2sv(s)));
  	PUTBACK;
  
  	/*
  	 * G_KEEPERR seems to be needed here, else we don't recognize compile
  	 * errors properly.  Perhaps it's because there's another level of eval
  	 * inside mksafefunc?
  	 */
  	count = perl_call_pv("PostgreSQL::InServer::mkfunc",
  						 G_SCALAR | G_EVAL | G_KEEPERR);
  	SPAGAIN;
  
  	if (count == 1)
  	{
  		SV		   *sub_rv = (SV *) POPs;
  
  		if (sub_rv && SvROK(sub_rv) && SvTYPE(SvRV(sub_rv)) == SVt_PVCV)
  		{
  			subref = newRV_inc(SvRV(sub_rv));
  		}
  	}
  
  	PUTBACK;
  	FREETMPS;
  	LEAVE;
  
  	if (SvTRUE(ERRSV))
  		ereport(ERROR,
  				(errcode(ERRCODE_SYNTAX_ERROR),
  				 errmsg("%s", strip_trailing_ws(sv2cstr(ERRSV)))));
  
  	if (!subref)
  		ereport(ERROR,
  		(errmsg("didn't get a CODE reference from compiling function \"%s\"",
  				prodesc->proname)));
  
  	prodesc->reference = subref;
  
  	return;
  }
  
  
  /**********************************************************************
   * plperl_init_shared_libs()		-
   **********************************************************************/
  
  static void
  plperl_init_shared_libs(pTHX)
  {
  	char	   *file = __FILE__;
  
  	newXS("DynaLoader::boot_DynaLoader", boot_DynaLoader, file);
  	newXS("PostgreSQL::InServer::Util::bootstrap",
  		  boot_PostgreSQL__InServer__Util, file);
  	/* newXS for...::SPI::bootstrap is in select_perl_context() */
  }
  
  
  static SV  *
  plperl_call_perl_func(plperl_proc_desc *desc, FunctionCallInfo fcinfo)
  {
  	dSP;
  	SV		   *retval;
  	int			i;
  	int			count;
  
  	ENTER;
  	SAVETMPS;
  
  	PUSHMARK(SP);
  	EXTEND(sp, desc->nargs);
  
  	for (i = 0; i < desc->nargs; i++)
  	{
  		if (fcinfo->argnull[i])
  			PUSHs(&PL_sv_undef);
  		else if (desc->arg_is_rowtype[i])
  		{
  			SV		   *sv = plperl_hash_from_datum(fcinfo->arg[i]);
  
  			PUSHs(sv_2mortal(sv));
  		}
  		else
  		{
  			SV		   *sv;
  
  			if (OidIsValid(desc->arg_arraytype[i]))
  				sv = plperl_ref_from_pg_array(fcinfo->arg[i], desc->arg_arraytype[i]);
  			else
  			{
  				char	   *tmp;
  
  				tmp = OutputFunctionCall(&(desc->arg_out_func[i]),
  										 fcinfo->arg[i]);
  				sv = cstr2sv(tmp);
  				pfree(tmp);
  			}
  
  			PUSHs(sv_2mortal(sv));
  		}
  	}
  	PUTBACK;
  
  	/* Do NOT use G_KEEPERR here */
  	count = perl_call_sv(desc->reference, G_SCALAR | G_EVAL);
  
  	SPAGAIN;
  
  	if (count != 1)
  	{
  		PUTBACK;
  		FREETMPS;
  		LEAVE;
  		elog(ERROR, "didn't get a return item from function");
  	}
  
  	if (SvTRUE(ERRSV))
  	{
  		(void) POPs;
  		PUTBACK;
  		FREETMPS;
  		LEAVE;
  		/* XXX need to find a way to assign an errcode here */
  		ereport(ERROR,
  				(errmsg("%s", strip_trailing_ws(sv2cstr(ERRSV)))));
  	}
  
  	retval = newSVsv(POPs);
  
  	PUTBACK;
  	FREETMPS;
  	LEAVE;
  
  	return retval;
  }
  
  
  static SV  *
  plperl_call_perl_trigger_func(plperl_proc_desc *desc, FunctionCallInfo fcinfo,
  							  SV *td)
  {
  	dSP;
  	SV		   *retval,
  			   *TDsv;
  	int			i,
  				count;
  	Trigger    *tg_trigger = ((TriggerData *) fcinfo->context)->tg_trigger;
  
  	ENTER;
  	SAVETMPS;
  
  	TDsv = get_sv("main::_TD", 0);
  	if (!TDsv)
  		elog(ERROR, "couldn't fetch $_TD");
  
  	save_item(TDsv);			/* local $_TD */
  	sv_setsv(TDsv, td);
  
  	PUSHMARK(sp);
  	EXTEND(sp, tg_trigger->tgnargs);
  
  	for (i = 0; i < tg_trigger->tgnargs; i++)
  		PUSHs(sv_2mortal(cstr2sv(tg_trigger->tgargs[i])));
  	PUTBACK;
  
  	/* Do NOT use G_KEEPERR here */
  	count = perl_call_sv(desc->reference, G_SCALAR | G_EVAL);
  
  	SPAGAIN;
  
  	if (count != 1)
  	{
  		PUTBACK;
  		FREETMPS;
  		LEAVE;
  		elog(ERROR, "didn't get a return item from trigger function");
  	}
  
  	if (SvTRUE(ERRSV))
  	{
  		(void) POPs;
  		PUTBACK;
  		FREETMPS;
  		LEAVE;
  		/* XXX need to find a way to assign an errcode here */
  		ereport(ERROR,
  				(errmsg("%s", strip_trailing_ws(sv2cstr(ERRSV)))));
  	}
  
  	retval = newSVsv(POPs);
  
  	PUTBACK;
  	FREETMPS;
  	LEAVE;
  
  	return retval;
  }
  
  
  static void
  plperl_call_perl_event_trigger_func(plperl_proc_desc *desc,
  									FunctionCallInfo fcinfo,
  									SV *td)
  {
  	dSP;
  	SV		   *retval,
  			   *TDsv;
  	int			count;
  
  	ENTER;
  	SAVETMPS;
  
  	TDsv = get_sv("main::_TD", 0);
  	if (!TDsv)
  		elog(ERROR, "couldn't fetch $_TD");
  
  	save_item(TDsv);			/* local $_TD */
  	sv_setsv(TDsv, td);
  
  	PUSHMARK(sp);
  	PUTBACK;
  
  	/* Do NOT use G_KEEPERR here */
  	count = perl_call_sv(desc->reference, G_SCALAR | G_EVAL);
  
  	SPAGAIN;
  
  	if (count != 1)
  	{
  		PUTBACK;
  		FREETMPS;
  		LEAVE;
  		elog(ERROR, "didn't get a return item from trigger function");
  	}
  
  	if (SvTRUE(ERRSV))
  	{
  		(void) POPs;
  		PUTBACK;
  		FREETMPS;
  		LEAVE;
  		/* XXX need to find a way to assign an errcode here */
  		ereport(ERROR,
  				(errmsg("%s", strip_trailing_ws(sv2cstr(ERRSV)))));
  	}
  
  	retval = newSVsv(POPs);
  	(void) retval;				/* silence compiler warning */
  
  	PUTBACK;
  	FREETMPS;
  	LEAVE;
  
  	return;
  }
  
  static Datum
  plperl_func_handler(PG_FUNCTION_ARGS)
  {
  	plperl_proc_desc *prodesc;
  	SV		   *perlret;
  	Datum		retval = 0;
  	ReturnSetInfo *rsi;
  	ErrorContextCallback pl_error_context;
  
  	if (SPI_connect() != SPI_OK_CONNECT)
  		elog(ERROR, "could not connect to SPI manager");
  
  	prodesc = compile_plperl_function(fcinfo->flinfo->fn_oid, false, false);
  	current_call_data->prodesc = prodesc;
  	increment_prodesc_refcount(prodesc);
  
  	/* Set a callback for error reporting */
  	pl_error_context.callback = plperl_exec_callback;
  	pl_error_context.previous = error_context_stack;
  	pl_error_context.arg = prodesc->proname;
  	error_context_stack = &pl_error_context;
  
  	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
  
  	if (prodesc->fn_retisset)
  	{
  		/* Check context before allowing the call to go through */
  		if (!rsi || !IsA(rsi, ReturnSetInfo) ||
  			(rsi->allowedModes & SFRM_Materialize) == 0 ||
  			rsi->expectedDesc == NULL)
  			ereport(ERROR,
  					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  					 errmsg("set-valued function called in context that "
  							"cannot accept a set")));
  	}
  
  	activate_interpreter(prodesc->interp);
  
  	perlret = plperl_call_perl_func(prodesc, fcinfo);
  
  	/************************************************************
  	 * Disconnect from SPI manager and then create the return
  	 * values datum (if the input function does a palloc for it
  	 * this must not be allocated in the SPI memory context
  	 * because SPI_finish would free it).
  	 ************************************************************/
  	if (SPI_finish() != SPI_OK_FINISH)
  		elog(ERROR, "SPI_finish() failed");
  
  	if (prodesc->fn_retisset)
  	{
  		SV		   *sav;
  
  		/*
  		 * If the Perl function returned an arrayref, we pretend that it
  		 * called return_next() for each element of the array, to handle old
  		 * SRFs that didn't know about return_next(). Any other sort of return
  		 * value is an error, except undef which means return an empty set.
  		 */
  		sav = get_perl_array_ref(perlret);
  		if (sav)
  		{
  			int			i = 0;
  			SV		  **svp = 0;
  			AV		   *rav = (AV *) SvRV(sav);
  
  			while ((svp = av_fetch(rav, i, FALSE)) != NULL)
  			{
  				plperl_return_next(*svp);
  				i++;
  			}
  		}
  		else if (SvOK(perlret))
  		{
  			ereport(ERROR,
  					(errcode(ERRCODE_DATATYPE_MISMATCH),
  					 errmsg("set-returning PL/Perl function must return "
  							"reference to array or use return_next")));
  		}
  
  		rsi->returnMode = SFRM_Materialize;
  		if (current_call_data->tuple_store)
  		{
  			rsi->setResult = current_call_data->tuple_store;
  			rsi->setDesc = current_call_data->ret_tdesc;
  		}
  		retval = (Datum) 0;
  	}
  	else
  	{
  		retval = plperl_sv_to_datum(perlret,
  									prodesc->result_oid,
  									-1,
  									fcinfo,
  									&prodesc->result_in_func,
  									prodesc->result_typioparam,
  									&fcinfo->isnull);
  
  		if (fcinfo->isnull && rsi && IsA(rsi, ReturnSetInfo))
  			rsi->isDone = ExprEndResult;
  	}
  
  	/* Restore the previous error callback */
  	error_context_stack = pl_error_context.previous;
  
  	SvREFCNT_dec(perlret);
  
  	return retval;
  }
  
  
  static Datum
  plperl_trigger_handler(PG_FUNCTION_ARGS)
  {
  	plperl_proc_desc *prodesc;
  	SV		   *perlret;
  	Datum		retval;
  	SV		   *svTD;
  	HV		   *hvTD;
  	ErrorContextCallback pl_error_context;
  
  	/* Connect to SPI manager */
  	if (SPI_connect() != SPI_OK_CONNECT)
  		elog(ERROR, "could not connect to SPI manager");
  
  	/* Find or compile the function */
  	prodesc = compile_plperl_function(fcinfo->flinfo->fn_oid, true, false);
  	current_call_data->prodesc = prodesc;
  	increment_prodesc_refcount(prodesc);
  
  	/* Set a callback for error reporting */
  	pl_error_context.callback = plperl_exec_callback;
  	pl_error_context.previous = error_context_stack;
  	pl_error_context.arg = prodesc->proname;
  	error_context_stack = &pl_error_context;
  
  	activate_interpreter(prodesc->interp);
  
  	svTD = plperl_trigger_build_args(fcinfo);
  	perlret = plperl_call_perl_trigger_func(prodesc, fcinfo, svTD);
  	hvTD = (HV *) SvRV(svTD);
  
  	/************************************************************
  	* Disconnect from SPI manager and then create the return
  	* values datum (if the input function does a palloc for it
  	* this must not be allocated in the SPI memory context
  	* because SPI_finish would free it).
  	************************************************************/
  	if (SPI_finish() != SPI_OK_FINISH)
  		elog(ERROR, "SPI_finish() failed");
  
  	if (perlret == NULL || !SvOK(perlret))
  	{
  		/* undef result means go ahead with original tuple */
  		TriggerData *trigdata = ((TriggerData *) fcinfo->context);
  
  		if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
  			retval = (Datum) trigdata->tg_trigtuple;
  		else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
  			retval = (Datum) trigdata->tg_newtuple;
  		else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
  			retval = (Datum) trigdata->tg_trigtuple;
  		else if (TRIGGER_FIRED_BY_TRUNCATE(trigdata->tg_event))
  			retval = (Datum) trigdata->tg_trigtuple;
  		else
  			retval = (Datum) 0; /* can this happen? */
  	}
  	else
  	{
  		HeapTuple	trv;
  		char	   *tmp;
  
  		tmp = sv2cstr(perlret);
  
  		if (pg_strcasecmp(tmp, "SKIP") == 0)
  			trv = NULL;
  		else if (pg_strcasecmp(tmp, "MODIFY") == 0)
  		{
  			TriggerData *trigdata = (TriggerData *) fcinfo->context;
  
  			if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
  				trv = plperl_modify_tuple(hvTD, trigdata,
  										  trigdata->tg_trigtuple);
  			else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
  				trv = plperl_modify_tuple(hvTD, trigdata,
  										  trigdata->tg_newtuple);
  			else
  			{
  				ereport(WARNING,
  						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
  						 errmsg("ignoring modified row in DELETE trigger")));
  				trv = NULL;
  			}
  		}
  		else
  		{
  			ereport(ERROR,
  					(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
  				  errmsg("result of PL/Perl trigger function must be undef, "
  						 "\"SKIP\", or \"MODIFY\"")));
  			trv = NULL;
  		}
  		retval = PointerGetDatum(trv);
  		pfree(tmp);
  	}
  
  	/* Restore the previous error callback */
  	error_context_stack = pl_error_context.previous;
  
  	SvREFCNT_dec(svTD);
  	if (perlret)
  		SvREFCNT_dec(perlret);
  
  	return retval;
  }
  
  
  static void
  plperl_event_trigger_handler(PG_FUNCTION_ARGS)
  {
  	plperl_proc_desc *prodesc;
  	SV		   *svTD;
  	ErrorContextCallback pl_error_context;
  
  	/* Connect to SPI manager */
  	if (SPI_connect() != SPI_OK_CONNECT)
  		elog(ERROR, "could not connect to SPI manager");
  
  	/* Find or compile the function */
  	prodesc = compile_plperl_function(fcinfo->flinfo->fn_oid, false, true);
  	current_call_data->prodesc = prodesc;
  	increment_prodesc_refcount(prodesc);
  
  	/* Set a callback for error reporting */
  	pl_error_context.callback = plperl_exec_callback;
  	pl_error_context.previous = error_context_stack;
  	pl_error_context.arg = prodesc->proname;
  	error_context_stack = &pl_error_context;
  
  	activate_interpreter(prodesc->interp);
  
  	svTD = plperl_event_trigger_build_args(fcinfo);
  	plperl_call_perl_event_trigger_func(prodesc, fcinfo, svTD);
  
  	if (SPI_finish() != SPI_OK_FINISH)
  		elog(ERROR, "SPI_finish() failed");
  
  	/* Restore the previous error callback */
  	error_context_stack = pl_error_context.previous;
  
  	SvREFCNT_dec(svTD);
  
  	return;
  }
  
  
  static bool
  validate_plperl_function(plperl_proc_ptr *proc_ptr, HeapTuple procTup)
  {
  	if (proc_ptr && proc_ptr->proc_ptr)
  	{
  		plperl_proc_desc *prodesc = proc_ptr->proc_ptr;
  		bool		uptodate;
  
  		/************************************************************
  		 * If it's present, must check whether it's still up to date.
  		 * This is needed because CREATE OR REPLACE FUNCTION can modify the
  		 * function's pg_proc entry without changing its OID.
  		 ************************************************************/
  		uptodate = (prodesc->fn_xmin == HeapTupleHeaderGetRawXmin(procTup->t_data) &&
  					ItemPointerEquals(&prodesc->fn_tid, &procTup->t_self));
  
  		if (uptodate)
  			return true;
  
  		/* Otherwise, unlink the obsoleted entry from the hashtable ... */
  		proc_ptr->proc_ptr = NULL;
  		/* ... and release the corresponding refcount, probably deleting it */
  		decrement_prodesc_refcount(prodesc);
  	}
  
  	return false;
  }
  
  
  static void
  free_plperl_function(plperl_proc_desc *prodesc)
  {
  	Assert(prodesc->refcount <= 0);
  	/* Release CODE reference, if we have one, from the appropriate interp */
  	if (prodesc->reference)
  	{
  		plperl_interp_desc *oldinterp = plperl_active_interp;
  
  		activate_interpreter(prodesc->interp);
  		SvREFCNT_dec(prodesc->reference);
  		activate_interpreter(oldinterp);
  	}
  	/* Get rid of what we conveniently can of our own structs */
  	/* (FmgrInfo subsidiary info will get leaked ...) */
  	if (prodesc->proname)
  		free(prodesc->proname);
  	free(prodesc);
  }
  
  
  static plperl_proc_desc *
  compile_plperl_function(Oid fn_oid, bool is_trigger, bool is_event_trigger)
  {
  	HeapTuple	procTup;
  	Form_pg_proc procStruct;
  	plperl_proc_key proc_key;
  	plperl_proc_ptr *proc_ptr;
  	plperl_proc_desc *prodesc = NULL;
  	int			i;
  	plperl_interp_desc *oldinterp = plperl_active_interp;
  	ErrorContextCallback plperl_error_context;
  
  	/* We'll need the pg_proc tuple in any case... */
  	procTup = SearchSysCache1(PROCOID, ObjectIdGetDatum(fn_oid));
  	if (!HeapTupleIsValid(procTup))
  		elog(ERROR, "cache lookup failed for function %u", fn_oid);
  	procStruct = (Form_pg_proc) GETSTRUCT(procTup);
  
  	/* Set a callback for reporting compilation errors */
  	plperl_error_context.callback = plperl_compile_callback;
  	plperl_error_context.previous = error_context_stack;
  	plperl_error_context.arg = NameStr(procStruct->proname);
  	error_context_stack = &plperl_error_context;
  
  	/* Try to find function in plperl_proc_hash */
  	proc_key.proc_id = fn_oid;
  	proc_key.is_trigger = is_trigger;
  	proc_key.user_id = GetUserId();
  
  	proc_ptr = hash_search(plperl_proc_hash, &proc_key,
  						   HASH_FIND, NULL);
  
  	if (validate_plperl_function(proc_ptr, procTup))
  		prodesc = proc_ptr->proc_ptr;
  	else
  	{
  		/* If not found or obsolete, maybe it's plperlu */
  		proc_key.user_id = InvalidOid;
  		proc_ptr = hash_search(plperl_proc_hash, &proc_key,
  							   HASH_FIND, NULL);
  		if (validate_plperl_function(proc_ptr, procTup))
  			prodesc = proc_ptr->proc_ptr;
  	}
  
  	/************************************************************
  	 * If we haven't found it in the hashtable, we analyze
  	 * the function's arguments and return type and store
  	 * the in-/out-functions in the prodesc block and create
  	 * a new hashtable entry for it.
  	 *
  	 * Then we load the procedure into the Perl interpreter.
  	 ************************************************************/
  	if (prodesc == NULL)
  	{
  		HeapTuple	langTup;
  		HeapTuple	typeTup;
  		Form_pg_language langStruct;
  		Form_pg_type typeStruct;
  		Datum		prosrcdatum;
  		bool		isnull;
  		char	   *proc_source;
  
  		/************************************************************
  		 * Allocate a new procedure description block
  		 ************************************************************/
  		prodesc = (plperl_proc_desc *) malloc(sizeof(plperl_proc_desc));
  		if (prodesc == NULL)
  			ereport(ERROR,
  					(errcode(ERRCODE_OUT_OF_MEMORY),
  					 errmsg("out of memory")));
  		/* Initialize all fields to 0 so free_plperl_function is safe */
  		MemSet(prodesc, 0, sizeof(plperl_proc_desc));
  
  		prodesc->proname = strdup(NameStr(procStruct->proname));
  		if (prodesc->proname == NULL)
  		{
  			free_plperl_function(prodesc);
  			ereport(ERROR,
  					(errcode(ERRCODE_OUT_OF_MEMORY),
  					 errmsg("out of memory")));
  		}
  		prodesc->fn_xmin = HeapTupleHeaderGetRawXmin(procTup->t_data);
  		prodesc->fn_tid = procTup->t_self;
  
  		/* Remember if function is STABLE/IMMUTABLE */
  		prodesc->fn_readonly =
  			(procStruct->provolatile != PROVOLATILE_VOLATILE);
  
  		/************************************************************
  		 * Lookup the pg_language tuple by Oid
  		 ************************************************************/
  		langTup = SearchSysCache1(LANGOID,
  								  ObjectIdGetDatum(procStruct->prolang));
  		if (!HeapTupleIsValid(langTup))
  		{
  			free_plperl_function(prodesc);
  			elog(ERROR, "cache lookup failed for language %u",
  				 procStruct->prolang);
  		}
  		langStruct = (Form_pg_language) GETSTRUCT(langTup);
  		prodesc->lanpltrusted = langStruct->lanpltrusted;
  		ReleaseSysCache(langTup);
  
  		/************************************************************
  		 * Get the required information for input conversion of the
  		 * return value.
  		 ************************************************************/
  		if (!is_trigger && !is_event_trigger)
  		{
  			typeTup =
  				SearchSysCache1(TYPEOID,
  								ObjectIdGetDatum(procStruct->prorettype));
  			if (!HeapTupleIsValid(typeTup))
  			{
  				free_plperl_function(prodesc);
  				elog(ERROR, "cache lookup failed for type %u",
  					 procStruct->prorettype);
  			}
  			typeStruct = (Form_pg_type) GETSTRUCT(typeTup);
  
  			/* Disallow pseudotype result, except VOID or RECORD */
  			if (typeStruct->typtype == TYPTYPE_PSEUDO)
  			{
  				if (procStruct->prorettype == VOIDOID ||
  					procStruct->prorettype == RECORDOID)
  					 /* okay */ ;
  				else if (procStruct->prorettype == TRIGGEROID ||
  						 procStruct->prorettype == EVTTRIGGEROID)
  				{
  					free_plperl_function(prodesc);
  					ereport(ERROR,
  							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  							 errmsg("trigger functions can only be called "
  									"as triggers")));
  				}
  				else
  				{
  					free_plperl_function(prodesc);
  					ereport(ERROR,
  							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  							 errmsg("PL/Perl functions cannot return type %s",
  									format_type_be(procStruct->prorettype))));
  				}
  			}
  
  			prodesc->result_oid = procStruct->prorettype;
  			prodesc->fn_retisset = procStruct->proretset;
  			prodesc->fn_retistuple = (procStruct->prorettype == RECORDOID ||
  								   typeStruct->typtype == TYPTYPE_COMPOSITE);
  
  			prodesc->fn_retisarray =
  				(typeStruct->typlen == -1 && typeStruct->typelem);
  
  			perm_fmgr_info(typeStruct->typinput, &(prodesc->result_in_func));
  			prodesc->result_typioparam = getTypeIOParam(typeTup);
  
  			ReleaseSysCache(typeTup);
  		}
  
  		/************************************************************
  		 * Get the required information for output conversion
  		 * of all procedure arguments
  		 ************************************************************/
  		if (!is_trigger && !is_event_trigger)
  		{
  			prodesc->nargs = procStruct->pronargs;
  			for (i = 0; i < prodesc->nargs; i++)
  			{
  				typeTup = SearchSysCache1(TYPEOID,
  						ObjectIdGetDatum(procStruct->proargtypes.values[i]));
  				if (!HeapTupleIsValid(typeTup))
  				{
  					free_plperl_function(prodesc);
  					elog(ERROR, "cache lookup failed for type %u",
  						 procStruct->proargtypes.values[i]);
  				}
  				typeStruct = (Form_pg_type) GETSTRUCT(typeTup);
  
  				/* Disallow pseudotype argument */
  				if (typeStruct->typtype == TYPTYPE_PSEUDO &&
  					procStruct->proargtypes.values[i] != RECORDOID)
  				{
  					free_plperl_function(prodesc);
  					ereport(ERROR,
  							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  							 errmsg("PL/Perl functions cannot accept type %s",
  						format_type_be(procStruct->proargtypes.values[i]))));
  				}
  
  				if (typeStruct->typtype == TYPTYPE_COMPOSITE ||
  					procStruct->proargtypes.values[i] == RECORDOID)
  					prodesc->arg_is_rowtype[i] = true;
  				else
  				{
  					prodesc->arg_is_rowtype[i] = false;
  					perm_fmgr_info(typeStruct->typoutput,
  								   &(prodesc->arg_out_func[i]));
  				}
  
  				/* Identify array attributes */
  				if (typeStruct->typelem != 0 && typeStruct->typlen == -1)
  					prodesc->arg_arraytype[i] = procStruct->proargtypes.values[i];
  				else
  					prodesc->arg_arraytype[i] = InvalidOid;
  
  				ReleaseSysCache(typeTup);
  			}
  		}
  
  		/************************************************************
  		 * create the text of the anonymous subroutine.
  		 * we do not use a named subroutine so that we can call directly
  		 * through the reference.
  		 ************************************************************/
  		prosrcdatum = SysCacheGetAttr(PROCOID, procTup,
  									  Anum_pg_proc_prosrc, &isnull);
  		if (isnull)
  			elog(ERROR, "null prosrc");
  		proc_source = TextDatumGetCString(prosrcdatum);
  
  		/************************************************************
  		 * Create the procedure in the appropriate interpreter
  		 ************************************************************/
  
  		select_perl_context(prodesc->lanpltrusted);
  
  		prodesc->interp = plperl_active_interp;
  
  		plperl_create_sub(prodesc, proc_source, fn_oid);
  
  		activate_interpreter(oldinterp);
  
  		pfree(proc_source);
  		if (!prodesc->reference)	/* can this happen? */
  		{
  			free_plperl_function(prodesc);
  			elog(ERROR, "could not create PL/Perl internal procedure");
  		}
  
  		/************************************************************
  		 * OK, link the procedure into the correct hashtable entry
  		 ************************************************************/
  		proc_key.user_id = prodesc->lanpltrusted ? GetUserId() : InvalidOid;
  
  		proc_ptr = hash_search(plperl_proc_hash, &proc_key,
  							   HASH_ENTER, NULL);
  		proc_ptr->proc_ptr = prodesc;
  		increment_prodesc_refcount(prodesc);
  	}
  
  	/* restore previous error callback */
  	error_context_stack = plperl_error_context.previous;
  
  	ReleaseSysCache(procTup);
  
  	return prodesc;
  }
  
  /* Build a hash from a given composite/row datum */
  static SV  *
  plperl_hash_from_datum(Datum attr)
  {
  	HeapTupleHeader td;
  	Oid			tupType;
  	int32		tupTypmod;
  	TupleDesc	tupdesc;
  	HeapTupleData tmptup;
  	SV		   *sv;
  
  	td = DatumGetHeapTupleHeader(attr);
  
  	/* Extract rowtype info and find a tupdesc */
  	tupType = HeapTupleHeaderGetTypeId(td);
  	tupTypmod = HeapTupleHeaderGetTypMod(td);
  	tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
  
  	/* Build a temporary HeapTuple control structure */
  	tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
  	tmptup.t_data = td;
  
  	sv = plperl_hash_from_tuple(&tmptup, tupdesc);
  	ReleaseTupleDesc(tupdesc);
  
  	return sv;
  }
  
  /* Build a hash from all attributes of a given tuple. */
  static SV  *
  plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc)
  {
  	HV		   *hv;
  	int			i;
  
  	/* since this function recurses, it could be driven to stack overflow */
  	check_stack_depth();
  
  	hv = newHV();
  	hv_ksplit(hv, tupdesc->natts);		/* pre-grow the hash */
  
  	for (i = 0; i < tupdesc->natts; i++)
  	{
  		Datum		attr;
  		bool		isnull,
  					typisvarlena;
  		char	   *attname;
  		Oid			typoutput;
  
  		if (tupdesc->attrs[i]->attisdropped)
  			continue;
  
  		attname = NameStr(tupdesc->attrs[i]->attname);
  		attr = heap_getattr(tuple, i + 1, tupdesc, &isnull);
  
  		if (isnull)
  		{
  			/*
  			 * Store (attname => undef) and move on.  Note we can't use
  			 * &PL_sv_undef here; see "AVs, HVs and undefined values" in
  			 * perlguts for an explanation.
  			 */
  			hv_store_string(hv, attname, newSV(0));
  			continue;
  		}
  
  		if (type_is_rowtype(tupdesc->attrs[i]->atttypid))
  		{
  			SV		   *sv = plperl_hash_from_datum(attr);
  
  			hv_store_string(hv, attname, sv);
  		}
  		else
  		{
  			SV		   *sv;
  
  			if (OidIsValid(get_base_element_type(tupdesc->attrs[i]->atttypid)))
  				sv = plperl_ref_from_pg_array(attr, tupdesc->attrs[i]->atttypid);
  			else
  			{
  				char	   *outputstr;
  
  				/* XXX should have a way to cache these lookups */
  				getTypeOutputInfo(tupdesc->attrs[i]->atttypid,
  								  &typoutput, &typisvarlena);
  
  				outputstr = OidOutputFunctionCall(typoutput, attr);
  				sv = cstr2sv(outputstr);
  				pfree(outputstr);
  			}
  
  			hv_store_string(hv, attname, sv);
  		}
  	}
  	return newRV_noinc((SV *) hv);
  }
  
  
  static void
  check_spi_usage_allowed()
  {
  	/* see comment in plperl_fini() */
  	if (plperl_ending)
  	{
  		/* simple croak as we don't want to involve PostgreSQL code */
  		croak("SPI functions can not be used in END blocks");
  	}
  }
  
  
  HV *
  plperl_spi_exec(char *query, int limit)
  {
  	HV		   *ret_hv;
  
  	/*
  	 * Execute the query inside a sub-transaction, so we can cope with errors
  	 * sanely
  	 */
  	MemoryContext oldcontext = CurrentMemoryContext;
  	ResourceOwner oldowner = CurrentResourceOwner;
  
  	check_spi_usage_allowed();
  
  	BeginInternalSubTransaction(NULL);
  	/* Want to run inside function's memory context */
  	MemoryContextSwitchTo(oldcontext);
  
  	PG_TRY();
  	{
  		int			spi_rv;
  
  		pg_verifymbstr(query, strlen(query), false);
  
  		spi_rv = SPI_execute(query, current_call_data->prodesc->fn_readonly,
  							 limit);
  		ret_hv = plperl_spi_execute_fetch_result(SPI_tuptable, SPI_processed,
  												 spi_rv);
  
  		/* Commit the inner transaction, return to outer xact context */
  		ReleaseCurrentSubTransaction();
  		MemoryContextSwitchTo(oldcontext);
  		CurrentResourceOwner = oldowner;
  
  		/*
  		 * AtEOSubXact_SPI() should not have popped any SPI context, but just
  		 * in case it did, make sure we remain connected.
  		 */
  		SPI_restore_connection();
  	}
  	PG_CATCH();
  	{
  		ErrorData  *edata;
  
  		/* Save error info */
  		MemoryContextSwitchTo(oldcontext);
  		edata = CopyErrorData();
  		FlushErrorState();
  
  		/* Abort the inner transaction */
  		RollbackAndReleaseCurrentSubTransaction();
  		MemoryContextSwitchTo(oldcontext);
  		CurrentResourceOwner = oldowner;
  
  		/*
  		 * If AtEOSubXact_SPI() popped any SPI context of the subxact, it will
  		 * have left us in a disconnected state.  We need this hack to return
  		 * to connected state.
  		 */
  		SPI_restore_connection();
  
  		/* Punt the error to Perl */
  		croak("%s", edata->message);
  
  		/* Can't get here, but keep compiler quiet */
  		return NULL;
  	}
  	PG_END_TRY();
  
  	return ret_hv;
  }
  
  
  static HV  *
  plperl_spi_execute_fetch_result(SPITupleTable *tuptable, int processed,
  								int status)
  {
  	HV		   *result;
  
  	check_spi_usage_allowed();
  
  	result = newHV();
  
  	hv_store_string(result, "status",
  					cstr2sv(SPI_result_code_string(status)));
  	hv_store_string(result, "processed",
  					newSViv(processed));
  
  	if (status > 0 && tuptable)
  	{
  		AV		   *rows;
  		SV		   *row;
  		int			i;
  
  		rows = newAV();
  		av_extend(rows, processed);
  		for (i = 0; i < processed; i++)
  		{
  			row = plperl_hash_from_tuple(tuptable->vals[i], tuptable->tupdesc);
  			av_push(rows, row);
  		}
  		hv_store_string(result, "rows",
  						newRV_noinc((SV *) rows));
  	}
  
  	SPI_freetuptable(tuptable);
  
  	return result;
  }
  
  
  /*
   * Note: plperl_return_next is called both in Postgres and Perl contexts.
   * We report any errors in Postgres fashion (via ereport).	If called in
   * Perl context, it is SPI.xs's responsibility to catch the error and
   * convert to a Perl error.  We assume (perhaps without adequate justification)
   * that we need not abort the current transaction if the Perl code traps the
   * error.
   */
  void
  plperl_return_next(SV *sv)
  {
  	plperl_proc_desc *prodesc;
  	FunctionCallInfo fcinfo;
  	ReturnSetInfo *rsi;
  	MemoryContext old_cxt;
  
  	if (!sv)
  		return;
  
  	prodesc = current_call_data->prodesc;
  	fcinfo = current_call_data->fcinfo;
  	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
  
  	if (!prodesc->fn_retisset)
  		ereport(ERROR,
  				(errcode(ERRCODE_SYNTAX_ERROR),
  				 errmsg("cannot use return_next in a non-SETOF function")));
  
  	if (!current_call_data->ret_tdesc)
  	{
  		TupleDesc	tupdesc;
  
  		Assert(!current_call_data->tuple_store);
  
  		/*
  		 * This is the first call to return_next in the current PL/Perl
  		 * function call, so memoize some lookups
  		 */
  		if (prodesc->fn_retistuple)
  			(void) get_call_result_type(fcinfo, NULL, &tupdesc);
  		else
  			tupdesc = rsi->expectedDesc;
  
  		/*
  		 * Make sure the tuple_store and ret_tdesc are sufficiently
  		 * long-lived.
  		 */
  		old_cxt = MemoryContextSwitchTo(rsi->econtext->ecxt_per_query_memory);
  
  		current_call_data->ret_tdesc = CreateTupleDescCopy(tupdesc);
  		current_call_data->tuple_store =
  			tuplestore_begin_heap(rsi->allowedModes & SFRM_Materialize_Random,
  								  false, work_mem);
  
  		MemoryContextSwitchTo(old_cxt);
  	}
  
  	/*
  	 * Producing the tuple we want to return requires making plenty of
  	 * palloc() allocations that are not cleaned up. Since this function can
  	 * be called many times before the current memory context is reset, we
  	 * need to do those allocations in a temporary context.
  	 */
  	if (!current_call_data->tmp_cxt)
  	{
  		current_call_data->tmp_cxt =
  			AllocSetContextCreate(CurrentMemoryContext,
  								  "PL/Perl return_next temporary cxt",
  								  ALLOCSET_DEFAULT_MINSIZE,
  								  ALLOCSET_DEFAULT_INITSIZE,
  								  ALLOCSET_DEFAULT_MAXSIZE);
  	}
  
  	old_cxt = MemoryContextSwitchTo(current_call_data->tmp_cxt);
  
  	if (prodesc->fn_retistuple)
  	{
  		HeapTuple	tuple;
  
  		if (!(SvOK(sv) && SvROK(sv) && SvTYPE(SvRV(sv)) == SVt_PVHV))
  			ereport(ERROR,
  					(errcode(ERRCODE_DATATYPE_MISMATCH),
  					 errmsg("SETOF-composite-returning PL/Perl function "
  							"must call return_next with reference to hash")));
  
  		tuple = plperl_build_tuple_result((HV *) SvRV(sv),
  										  current_call_data->ret_tdesc);
  		tuplestore_puttuple(current_call_data->tuple_store, tuple);
  	}
  	else
  	{
  		Datum		ret;
  		bool		isNull;
  
  		ret = plperl_sv_to_datum(sv,
  								 prodesc->result_oid,
  								 -1,
  								 fcinfo,
  								 &prodesc->result_in_func,
  								 prodesc->result_typioparam,
  								 &isNull);
  
  		tuplestore_putvalues(current_call_data->tuple_store,
  							 current_call_data->ret_tdesc,
  							 &ret, &isNull);
  	}
  
  	MemoryContextSwitchTo(old_cxt);
  	MemoryContextReset(current_call_data->tmp_cxt);
  }
  
  
  SV *
  plperl_spi_query(char *query)
  {
  	SV		   *cursor;
  
  	/*
  	 * Execute the query inside a sub-transaction, so we can cope with errors
  	 * sanely
  	 */
  	MemoryContext oldcontext = CurrentMemoryContext;
  	ResourceOwner oldowner = CurrentResourceOwner;
  
  	check_spi_usage_allowed();
  
  	BeginInternalSubTransaction(NULL);
  	/* Want to run inside function's memory context */
  	MemoryContextSwitchTo(oldcontext);
  
  	PG_TRY();
  	{
  		SPIPlanPtr	plan;
  		Portal		portal;
  
  		/* Make sure the query is validly encoded */
  		pg_verifymbstr(query, strlen(query), false);
  
  		/* Create a cursor for the query */
  		plan = SPI_prepare(query, 0, NULL);
  		if (plan == NULL)
  			elog(ERROR, "SPI_prepare() failed:%s",
  				 SPI_result_code_string(SPI_result));
  
  		portal = SPI_cursor_open(NULL, plan, NULL, NULL, false);
  		SPI_freeplan(plan);
  		if (portal == NULL)
  			elog(ERROR, "SPI_cursor_open() failed:%s",
  				 SPI_result_code_string(SPI_result));
  		cursor = cstr2sv(portal->name);
  
  		/* Commit the inner transaction, return to outer xact context */
  		ReleaseCurrentSubTransaction();
  		MemoryContextSwitchTo(oldcontext);
  		CurrentResourceOwner = oldowner;
  
  		/*
  		 * AtEOSubXact_SPI() should not have popped any SPI context, but just
  		 * in case it did, make sure we remain connected.
  		 */
  		SPI_restore_connection();
  	}
  	PG_CATCH();
  	{
  		ErrorData  *edata;
  
  		/* Save error info */
  		MemoryContextSwitchTo(oldcontext);
  		edata = CopyErrorData();
  		FlushErrorState();
  
  		/* Abort the inner transaction */
  		RollbackAndReleaseCurrentSubTransaction();
  		MemoryContextSwitchTo(oldcontext);
  		CurrentResourceOwner = oldowner;
  
  		/*
  		 * If AtEOSubXact_SPI() popped any SPI context of the subxact, it will
  		 * have left us in a disconnected state.  We need this hack to return
  		 * to connected state.
  		 */
  		SPI_restore_connection();
  
  		/* Punt the error to Perl */
  		croak("%s", edata->message);
  
  		/* Can't get here, but keep compiler quiet */
  		return NULL;
  	}
  	PG_END_TRY();
  
  	return cursor;
  }
  
  
  SV *
  plperl_spi_fetchrow(char *cursor)
  {
  	SV		   *row;
  
  	/*
  	 * Execute the FETCH inside a sub-transaction, so we can cope with errors
  	 * sanely
  	 */
  	MemoryContext oldcontext = CurrentMemoryContext;
  	ResourceOwner oldowner = CurrentResourceOwner;
  
  	check_spi_usage_allowed();
  
  	BeginInternalSubTransaction(NULL);
  	/* Want to run inside function's memory context */
  	MemoryContextSwitchTo(oldcontext);
  
  	PG_TRY();
  	{
  		Portal		p = SPI_cursor_find(cursor);
  
  		if (!p)
  		{
  			row = &PL_sv_undef;
  		}
  		else
  		{
  			SPI_cursor_fetch(p, true, 1);
  			if (SPI_processed == 0)
  			{
  				SPI_cursor_close(p);
  				row = &PL_sv_undef;
  			}
  			else
  			{
  				row = plperl_hash_from_tuple(SPI_tuptable->vals[0],
  											 SPI_tuptable->tupdesc);
  			}
  			SPI_freetuptable(SPI_tuptable);
  		}
  
  		/* Commit the inner transaction, return to outer xact context */
  		ReleaseCurrentSubTransaction();
  		MemoryContextSwitchTo(oldcontext);
  		CurrentResourceOwner = oldowner;
  
  		/*
  		 * AtEOSubXact_SPI() should not have popped any SPI context, but just
  		 * in case it did, make sure we remain connected.
  		 */
  		SPI_restore_connection();
  	}
  	PG_CATCH();
  	{
  		ErrorData  *edata;
  
  		/* Save error info */
  		MemoryContextSwitchTo(oldcontext);
  		edata = CopyErrorData();
  		FlushErrorState();
  
  		/* Abort the inner transaction */
  		RollbackAndReleaseCurrentSubTransaction();
  		MemoryContextSwitchTo(oldcontext);
  		CurrentResourceOwner = oldowner;
  
  		/*
  		 * If AtEOSubXact_SPI() popped any SPI context of the subxact, it will
  		 * have left us in a disconnected state.  We need this hack to return
  		 * to connected state.
  		 */
  		SPI_restore_connection();
  
  		/* Punt the error to Perl */
  		croak("%s", edata->message);
  
  		/* Can't get here, but keep compiler quiet */
  		return NULL;
  	}
  	PG_END_TRY();
  
  	return row;
  }
  
  void
  plperl_spi_cursor_close(char *cursor)
  {
  	Portal		p;
  
  	check_spi_usage_allowed();
  
  	p = SPI_cursor_find(cursor);
  
  	if (p)
  		SPI_cursor_close(p);
  }
  
  SV *
  plperl_spi_prepare(char *query, int argc, SV **argv)
  {
  	volatile SPIPlanPtr plan = NULL;
  	volatile MemoryContext plan_cxt = NULL;
  	plperl_query_desc *volatile qdesc = NULL;
  	plperl_query_entry *volatile hash_entry = NULL;
  	MemoryContext oldcontext = CurrentMemoryContext;
  	ResourceOwner oldowner = CurrentResourceOwner;
  	MemoryContext work_cxt;
  	bool		found;
  	int			i;
  
  	check_spi_usage_allowed();
  
  	BeginInternalSubTransaction(NULL);
  	MemoryContextSwitchTo(oldcontext);
  
  	PG_TRY();
  	{
  		CHECK_FOR_INTERRUPTS();
  
  		/************************************************************
  		 * Allocate the new querydesc structure
  		 *
  		 * The qdesc struct, as well as all its subsidiary data, lives in its
  		 * plan_cxt.  But note that the SPIPlan does not.
  		 ************************************************************/
  		plan_cxt = AllocSetContextCreate(TopMemoryContext,
  										 "PL/Perl spi_prepare query",
  										 ALLOCSET_SMALL_MINSIZE,
  										 ALLOCSET_SMALL_INITSIZE,
  										 ALLOCSET_SMALL_MAXSIZE);
  		MemoryContextSwitchTo(plan_cxt);
  		qdesc = (plperl_query_desc *) palloc0(sizeof(plperl_query_desc));
  		snprintf(qdesc->qname, sizeof(qdesc->qname), "%p", qdesc);
  		qdesc->plan_cxt = plan_cxt;
  		qdesc->nargs = argc;
  		qdesc->argtypes = (Oid *) palloc(argc * sizeof(Oid));
  		qdesc->arginfuncs = (FmgrInfo *) palloc(argc * sizeof(FmgrInfo));
  		qdesc->argtypioparams = (Oid *) palloc(argc * sizeof(Oid));
  		MemoryContextSwitchTo(oldcontext);
  
  		/************************************************************
  		 * Do the following work in a short-lived context so that we don't
  		 * leak a lot of memory in the PL/Perl function's SPI Proc context.
  		 ************************************************************/
  		work_cxt = AllocSetContextCreate(CurrentMemoryContext,
  										 "PL/Perl spi_prepare workspace",
  										 ALLOCSET_DEFAULT_MINSIZE,
  										 ALLOCSET_DEFAULT_INITSIZE,
  										 ALLOCSET_DEFAULT_MAXSIZE);
  		MemoryContextSwitchTo(work_cxt);
  
  		/************************************************************
  		 * Resolve argument type names and then look them up by oid
  		 * in the system cache, and remember the required information
  		 * for input conversion.
  		 ************************************************************/
  		for (i = 0; i < argc; i++)
  		{
  			Oid			typId,
  						typInput,
  						typIOParam;
  			int32		typmod;
  			char	   *typstr;
  
  			typstr = sv2cstr(argv[i]);
  			parseTypeString(typstr, &typId, &typmod);
  			pfree(typstr);
  
  			getTypeInputInfo(typId, &typInput, &typIOParam);
  
  			qdesc->argtypes[i] = typId;
  			fmgr_info_cxt(typInput, &(qdesc->arginfuncs[i]), plan_cxt);
  			qdesc->argtypioparams[i] = typIOParam;
  		}
  
  		/* Make sure the query is validly encoded */
  		pg_verifymbstr(query, strlen(query), false);
  
  		/************************************************************
  		 * Prepare the plan and check for errors
  		 ************************************************************/
  		plan = SPI_prepare(query, argc, qdesc->argtypes);
  
  		if (plan == NULL)
  			elog(ERROR, "SPI_prepare() failed:%s",
  				 SPI_result_code_string(SPI_result));
  
  		/************************************************************
  		 * Save the plan into permanent memory (right now it's in the
  		 * SPI procCxt, which will go away at function end).
  		 ************************************************************/
  		if (SPI_keepplan(plan))
  			elog(ERROR, "SPI_keepplan() failed");
  		qdesc->plan = plan;
  
  		/************************************************************
  		 * Insert a hashtable entry for the plan.
  		 ************************************************************/
  		hash_entry = hash_search(plperl_active_interp->query_hash,
  								 qdesc->qname,
  								 HASH_ENTER, &found);
  		hash_entry->query_data = qdesc;
  
  		/* Get rid of workspace */
  		MemoryContextDelete(work_cxt);
  
  		/* Commit the inner transaction, return to outer xact context */
  		ReleaseCurrentSubTransaction();
  		MemoryContextSwitchTo(oldcontext);
  		CurrentResourceOwner = oldowner;
  
  		/*
  		 * AtEOSubXact_SPI() should not have popped any SPI context, but just
  		 * in case it did, make sure we remain connected.
  		 */
  		SPI_restore_connection();
  	}
  	PG_CATCH();
  	{
  		ErrorData  *edata;
  
  		/* Save error info */
  		MemoryContextSwitchTo(oldcontext);
  		edata = CopyErrorData();
  		FlushErrorState();
  
  		/* Drop anything we managed to allocate */
  		if (hash_entry)
  			hash_search(plperl_active_interp->query_hash,
  						qdesc->qname,
  						HASH_REMOVE, NULL);
  		if (plan_cxt)
  			MemoryContextDelete(plan_cxt);
  		if (plan)
  			SPI_freeplan(plan);
  
  		/* Abort the inner transaction */
  		RollbackAndReleaseCurrentSubTransaction();
  		MemoryContextSwitchTo(oldcontext);
  		CurrentResourceOwner = oldowner;
  
  		/*
  		 * If AtEOSubXact_SPI() popped any SPI context of the subxact, it will
  		 * have left us in a disconnected state.  We need this hack to return
  		 * to connected state.
  		 */
  		SPI_restore_connection();
  
  		/* Punt the error to Perl */
  		croak("%s", edata->message);
  
  		/* Can't get here, but keep compiler quiet */
  		return NULL;
  	}
  	PG_END_TRY();
  
  	/************************************************************
  	 * Return the query's hash key to the caller.
  	 ************************************************************/
  	return cstr2sv(qdesc->qname);
  }
  
  HV *
  plperl_spi_exec_prepared(char *query, HV *attr, int argc, SV **argv)
  {
  	HV		   *ret_hv;
  	SV		  **sv;
  	int			i,
  				limit,
  				spi_rv;
  	char	   *nulls;
  	Datum	   *argvalues;
  	plperl_query_desc *qdesc;
  	plperl_query_entry *hash_entry;
  
  	/*
  	 * Execute the query inside a sub-transaction, so we can cope with errors
  	 * sanely
  	 */
  	MemoryContext oldcontext = CurrentMemoryContext;
  	ResourceOwner oldowner = CurrentResourceOwner;
  
  	check_spi_usage_allowed();
  
  	BeginInternalSubTransaction(NULL);
  	/* Want to run inside function's memory context */
  	MemoryContextSwitchTo(oldcontext);
  
  	PG_TRY();
  	{
  		/************************************************************
  		 * Fetch the saved plan descriptor, see if it's o.k.
  		 ************************************************************/
  		hash_entry = hash_search(plperl_active_interp->query_hash, query,
  								 HASH_FIND, NULL);
  		if (hash_entry == NULL)
  			elog(ERROR, "spi_exec_prepared: Invalid prepared query passed");
  
  		qdesc = hash_entry->query_data;
  		if (qdesc == NULL)
  			elog(ERROR, "spi_exec_prepared: plperl query_hash value vanished");
  
  		if (qdesc->nargs != argc)
  			elog(ERROR, "spi_exec_prepared: expected %d argument(s), %d passed",
  				 qdesc->nargs, argc);
  
  		/************************************************************
  		 * Parse eventual attributes
  		 ************************************************************/
  		limit = 0;
  		if (attr != NULL)
  		{
  			sv = hv_fetch_string(attr, "limit");
  			if (sv && *sv && SvIOK(*sv))
  				limit = SvIV(*sv);
  		}
  		/************************************************************
  		 * Set up arguments
  		 ************************************************************/
  		if (argc > 0)
  		{
  			nulls = (char *) palloc(argc);
  			argvalues = (Datum *) palloc(argc * sizeof(Datum));
  		}
  		else
  		{
  			nulls = NULL;
  			argvalues = NULL;
  		}
  
  		for (i = 0; i < argc; i++)
  		{
  			bool		isnull;
  
  			argvalues[i] = plperl_sv_to_datum(argv[i],
  											  qdesc->argtypes[i],
  											  -1,
  											  NULL,
  											  &qdesc->arginfuncs[i],
  											  qdesc->argtypioparams[i],
  											  &isnull);
  			nulls[i] = isnull ? 'n' : ' ';
  		}
  
  		/************************************************************
  		 * go
  		 ************************************************************/
  		spi_rv = SPI_execute_plan(qdesc->plan, argvalues, nulls,
  							 current_call_data->prodesc->fn_readonly, limit);
  		ret_hv = plperl_spi_execute_fetch_result(SPI_tuptable, SPI_processed,
  												 spi_rv);
  		if (argc > 0)
  		{
  			pfree(argvalues);
  			pfree(nulls);
  		}
  
  		/* Commit the inner transaction, return to outer xact context */
  		ReleaseCurrentSubTransaction();
  		MemoryContextSwitchTo(oldcontext);
  		CurrentResourceOwner = oldowner;
  
  		/*
  		 * AtEOSubXact_SPI() should not have popped any SPI context, but just
  		 * in case it did, make sure we remain connected.
  		 */
  		SPI_restore_connection();
  	}
  	PG_CATCH();
  	{
  		ErrorData  *edata;
  
  		/* Save error info */
  		MemoryContextSwitchTo(oldcontext);
  		edata = CopyErrorData();
  		FlushErrorState();
  
  		/* Abort the inner transaction */
  		RollbackAndReleaseCurrentSubTransaction();
  		MemoryContextSwitchTo(oldcontext);
  		CurrentResourceOwner = oldowner;
  
  		/*
  		 * If AtEOSubXact_SPI() popped any SPI context of the subxact, it will
  		 * have left us in a disconnected state.  We need this hack to return
  		 * to connected state.
  		 */
  		SPI_restore_connection();
  
  		/* Punt the error to Perl */
  		croak("%s", edata->message);
  
  		/* Can't get here, but keep compiler quiet */
  		return NULL;
  	}
  	PG_END_TRY();
  
  	return ret_hv;
  }
  
  SV *
  plperl_spi_query_prepared(char *query, int argc, SV **argv)
  {
  	int			i;
  	char	   *nulls;
  	Datum	   *argvalues;
  	plperl_query_desc *qdesc;
  	plperl_query_entry *hash_entry;
  	SV		   *cursor;
  	Portal		portal = NULL;
  
  	/*
  	 * Execute the query inside a sub-transaction, so we can cope with errors
  	 * sanely
  	 */
  	MemoryContext oldcontext = CurrentMemoryContext;
  	ResourceOwner oldowner = CurrentResourceOwner;
  
  	check_spi_usage_allowed();
  
  	BeginInternalSubTransaction(NULL);
  	/* Want to run inside function's memory context */
  	MemoryContextSwitchTo(oldcontext);
  
  	PG_TRY();
  	{
  		/************************************************************
  		 * Fetch the saved plan descriptor, see if it's o.k.
  		 ************************************************************/
  		hash_entry = hash_search(plperl_active_interp->query_hash, query,
  								 HASH_FIND, NULL);
  		if (hash_entry == NULL)
  			elog(ERROR, "spi_query_prepared: Invalid prepared query passed");
  
  		qdesc = hash_entry->query_data;
  		if (qdesc == NULL)
  			elog(ERROR, "spi_query_prepared: plperl query_hash value vanished");
  
  		if (qdesc->nargs != argc)
  			elog(ERROR, "spi_query_prepared: expected %d argument(s), %d passed",
  				 qdesc->nargs, argc);
  
  		/************************************************************
  		 * Set up arguments
  		 ************************************************************/
  		if (argc > 0)
  		{
  			nulls = (char *) palloc(argc);
  			argvalues = (Datum *) palloc(argc * sizeof(Datum));
  		}
  		else
  		{
  			nulls = NULL;
  			argvalues = NULL;
  		}
  
  		for (i = 0; i < argc; i++)
  		{
  			bool		isnull;
  
  			argvalues[i] = plperl_sv_to_datum(argv[i],
  											  qdesc->argtypes[i],
  											  -1,
  											  NULL,
  											  &qdesc->arginfuncs[i],
  											  qdesc->argtypioparams[i],
  											  &isnull);
  			nulls[i] = isnull ? 'n' : ' ';
  		}
  
  		/************************************************************
  		 * go
  		 ************************************************************/
  		portal = SPI_cursor_open(NULL, qdesc->plan, argvalues, nulls,
  								 current_call_data->prodesc->fn_readonly);
  		if (argc > 0)
  		{
  			pfree(argvalues);
  			pfree(nulls);
  		}
  		if (portal == NULL)
  			elog(ERROR, "SPI_cursor_open() failed:%s",
  				 SPI_result_code_string(SPI_result));
  
  		cursor = cstr2sv(portal->name);
  
  		/* Commit the inner transaction, return to outer xact context */
  		ReleaseCurrentSubTransaction();
  		MemoryContextSwitchTo(oldcontext);
  		CurrentResourceOwner = oldowner;
  
  		/*
  		 * AtEOSubXact_SPI() should not have popped any SPI context, but just
  		 * in case it did, make sure we remain connected.
  		 */
  		SPI_restore_connection();
  	}
  	PG_CATCH();
  	{
  		ErrorData  *edata;
  
  		/* Save error info */
  		MemoryContextSwitchTo(oldcontext);
  		edata = CopyErrorData();
  		FlushErrorState();
  
  		/* Abort the inner transaction */
  		RollbackAndReleaseCurrentSubTransaction();
  		MemoryContextSwitchTo(oldcontext);
  		CurrentResourceOwner = oldowner;
  
  		/*
  		 * If AtEOSubXact_SPI() popped any SPI context of the subxact, it will
  		 * have left us in a disconnected state.  We need this hack to return
  		 * to connected state.
  		 */
  		SPI_restore_connection();
  
  		/* Punt the error to Perl */
  		croak("%s", edata->message);
  
  		/* Can't get here, but keep compiler quiet */
  		return NULL;
  	}
  	PG_END_TRY();
  
  	return cursor;
  }
  
  void
  plperl_spi_freeplan(char *query)
  {
  	SPIPlanPtr	plan;
  	plperl_query_desc *qdesc;
  	plperl_query_entry *hash_entry;
  
  	check_spi_usage_allowed();
  
  	hash_entry = hash_search(plperl_active_interp->query_hash, query,
  							 HASH_FIND, NULL);
  	if (hash_entry == NULL)
  		elog(ERROR, "spi_freeplan: Invalid prepared query passed");
  
  	qdesc = hash_entry->query_data;
  	if (qdesc == NULL)
  		elog(ERROR, "spi_freeplan: plperl query_hash value vanished");
  	plan = qdesc->plan;
  
  	/*
  	 * free all memory before SPI_freeplan, so if it dies, nothing will be
  	 * left over
  	 */
  	hash_search(plperl_active_interp->query_hash, query,
  				HASH_REMOVE, NULL);
  
  	MemoryContextDelete(qdesc->plan_cxt);
  
  	SPI_freeplan(plan);
  }
  
  /*
   * Store an SV into a hash table under a key that is a string assumed to be
   * in the current database's encoding.
   */
  static SV **
  hv_store_string(HV *hv, const char *key, SV *val)
  {
  	int32		hlen;
  	char	   *hkey;
  	SV		  **ret;
  
  	hkey = (char *)
  		pg_do_encoding_conversion((unsigned char *) key, strlen(key),
  								  GetDatabaseEncoding(), PG_UTF8);
  
  	/*
  	 * This seems nowhere documented, but under Perl 5.8.0 and up, hv_store()
  	 * recognizes a negative klen parameter as meaning a UTF-8 encoded key. It
  	 * does not appear that hashes track UTF-8-ness of keys at all in Perl
  	 * 5.6.
  	 */
  	hlen = -(int) strlen(hkey);
  	ret = hv_store(hv, hkey, hlen, val, 0);
  
  	if (hkey != key)
  		pfree(hkey);
  
  	return ret;
  }
  
  /*
   * Fetch an SV from a hash table under a key that is a string assumed to be
   * in the current database's encoding.
   */
  static SV **
  hv_fetch_string(HV *hv, const char *key)
  {
  	int32		hlen;
  	char	   *hkey;
  	SV		  **ret;
  
  	hkey = (char *)
  		pg_do_encoding_conversion((unsigned char *) key, strlen(key),
  								  GetDatabaseEncoding(), PG_UTF8);
  
  	/* See notes in hv_store_string */
  	hlen = -(int) strlen(hkey);
  	ret = hv_fetch(hv, hkey, hlen, 0);
  
  	if (hkey != key)
  		pfree(hkey);
  
  	return ret;
  }
  
  /*
   * Provide function name for PL/Perl execution errors
   */
  static void
  plperl_exec_callback(void *arg)
  {
  	char	   *procname = (char *) arg;
  
  	if (procname)
  		errcontext("PL/Perl function \"%s\"", procname);
  }
  
  /*
   * Provide function name for PL/Perl compilation errors
   */
  static void
  plperl_compile_callback(void *arg)
  {
  	char	   *procname = (char *) arg;
  
  	if (procname)
  		errcontext("compilation of PL/Perl function \"%s\"", procname);
  }
  
  /*
   * Provide error context for the inline handler
   */
  static void
  plperl_inline_callback(void *arg)
  {
  	errcontext("PL/Perl anonymous code block");
  }
  
  
  /*
   * Perl's own setlocal() copied from POSIX.xs
   * (needed because of the calls to new_*())
   */
  #ifdef WIN32
  static char *
  setlocale_perl(int category, char *locale)
  {
  	char	   *RETVAL = setlocale(category, locale);
  
  	if (RETVAL)
  	{
  #ifdef USE_LOCALE_CTYPE
  		if (category == LC_CTYPE
  #ifdef LC_ALL
  			|| category == LC_ALL
  #endif
  			)
  		{
  			char	   *newctype;
  
  #ifdef LC_ALL
  			if (category == LC_ALL)
  				newctype = setlocale(LC_CTYPE, NULL);
  			else
  #endif
  				newctype = RETVAL;
  			new_ctype(newctype);
  		}
  #endif   /* USE_LOCALE_CTYPE */
  #ifdef USE_LOCALE_COLLATE
  		if (category == LC_COLLATE
  #ifdef LC_ALL
  			|| category == LC_ALL
  #endif
  			)
  		{
  			char	   *newcoll;
  
  #ifdef LC_ALL
  			if (category == LC_ALL)
  				newcoll = setlocale(LC_COLLATE, NULL);
  			else
  #endif
  				newcoll = RETVAL;
  			new_collate(newcoll);
  		}
  #endif   /* USE_LOCALE_COLLATE */
  
  #ifdef USE_LOCALE_NUMERIC
  		if (category == LC_NUMERIC
  #ifdef LC_ALL
  			|| category == LC_ALL
  #endif
  			)
  		{
  			char	   *newnum;
  
  #ifdef LC_ALL
  			if (category == LC_ALL)
  				newnum = setlocale(LC_NUMERIC, NULL);
  			else
  #endif
  				newnum = RETVAL;
  			new_numeric(newnum);
  		}
  #endif   /* USE_LOCALE_NUMERIC */
  	}
  
  	return RETVAL;
  }
  
  #endif
  