pl_funcs.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

/**********************************************************************
 * pl_funcs.c		- Misc functions for the PL/pgSQL
 *			  procedural language
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_funcs.c,v 1.46.2.1 2005/11/22 18:23:30 momjian Exp $
 *
 *	  This software is copyrighted by Jan Wieck - Hamburg.
 *
 *	  The author hereby grants permission  to  use,  copy,	modify,
 *	  distribute,  and	license this software and its documentation
 *	  for any purpose, provided that existing copyright notices are
 *	  retained	in	all  copies  and  that	this notice is included
 *	  verbatim in any distributions. No written agreement, license,
 *	  or  royalty  fee	is required for any of the authorized uses.
 *	  Modifications to this software may be  copyrighted  by  their
 *	  author  and  need  not  follow  the licensing terms described
 *	  here, provided that the new terms are  clearly  indicated  on
 *	  the first page of each file where they apply.
 *
 *	  IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY
 *	  PARTY  FOR  DIRECT,	INDIRECT,	SPECIAL,   INCIDENTAL,	 OR
 *	  CONSEQUENTIAL   DAMAGES  ARISING	OUT  OF  THE  USE  OF  THIS
 *	  SOFTWARE, ITS DOCUMENTATION, OR ANY DERIVATIVES THEREOF, EVEN
 *	  IF  THE  AUTHOR  HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
 *	  DAMAGE.
 *
 *	  THE  AUTHOR  AND	DISTRIBUTORS  SPECIFICALLY	 DISCLAIM	ANY
 *	  WARRANTIES,  INCLUDING,  BUT	NOT  LIMITED  TO,  THE	IMPLIED
 *	  WARRANTIES  OF  MERCHANTABILITY,	FITNESS  FOR  A  PARTICULAR
 *	  PURPOSE,	AND NON-INFRINGEMENT.  THIS SOFTWARE IS PROVIDED ON
 *	  AN "AS IS" BASIS, AND THE AUTHOR	AND  DISTRIBUTORS  HAVE  NO
 *	  OBLIGATION   TO	PROVIDE   MAINTENANCE,	 SUPPORT,  UPDATES,
 *	  ENHANCEMENTS, OR MODIFICATIONS.
 *
 **********************************************************************/

#include "plpgsql.h"
#include "pl.tab.h"

#include <ctype.h>

#include "parser/scansup.h"


/* ----------
 * Local variables for the namestack handling
 * ----------
 */
static PLpgSQL_ns *ns_current = NULL;
static bool ns_localmode = false;


/* ----------
 * plpgsql_dstring_init			Dynamic string initialization
 * ----------
 */
void
plpgsql_dstring_init(PLpgSQL_dstring *ds)
{
	ds->value = palloc(ds->alloc = 512);
	ds->used = 1;
	ds->value[0] = '\0';
}


/* ----------
 * plpgsql_dstring_free			Dynamic string destruction
 * ----------
 */
void
plpgsql_dstring_free(PLpgSQL_dstring *ds)
{
	pfree(ds->value);
}

static void
plpgsql_dstring_expand(PLpgSQL_dstring *ds, int needed)
{
	/* Don't allow truncating the string */
	Assert(needed > ds->alloc);
	Assert(ds->used <= ds->alloc);

	/* Might have to double more than once, if needed is large */
	do
	{
		ds->alloc *= 2;
	} while (needed > ds->alloc);
	ds->value = repalloc(ds->value, ds->alloc);
}

/* ----------
 * plpgsql_dstring_append		Dynamic string extending
 * ----------
 */
void
plpgsql_dstring_append(PLpgSQL_dstring *ds, const char *str)
{
	int			len = strlen(str);
	int			needed = ds->used + len;

	if (needed > ds->alloc)
		plpgsql_dstring_expand(ds, needed);

	memcpy(&(ds->value[ds->used - 1]), str, len);
	ds->used += len;
	ds->value[ds->used - 1] = '\0';
}

/* ----------
 * plpgsql_dstring_append_char	Append a single character
 *								to a dynamic string
 * ----------
 */
void
plpgsql_dstring_append_char(PLpgSQL_dstring *ds, char c)
{
	if (ds->used == ds->alloc)
		plpgsql_dstring_expand(ds, ds->used + 1);

	ds->value[ds->used - 1] = c;
	ds->value[ds->used] = '\0';
	ds->used++;
}


/* ----------
 * plpgsql_dstring_get			Dynamic string get value
 * ----------
 */
char *
plpgsql_dstring_get(PLpgSQL_dstring *ds)
{
	return ds->value;
}


/* ----------
 * plpgsql_ns_init			Initialize the namestack
 * ----------
 */
void
plpgsql_ns_init(void)
{
	ns_current = NULL;
	ns_localmode = false;
}


/* ----------
 * plpgsql_ns_setlocal			Tell plpgsql_ns_lookup to or to
 *					not look into the current level
 *					only.
 * ----------
 */
bool
plpgsql_ns_setlocal(bool flag)
{
	bool		oldstate;

	oldstate = ns_localmode;
	ns_localmode = flag;
	return oldstate;
}


/* ----------
 * plpgsql_ns_push			Enter a new namestack level
 * ----------
 */
void
plpgsql_ns_push(char *label)
{
	PLpgSQL_ns *new;

	if (label == NULL)
		label = "";

	new = palloc(sizeof(PLpgSQL_ns));
	memset(new, 0, sizeof(PLpgSQL_ns));
	new->upper = ns_current;
	ns_current = new;

	plpgsql_ns_additem(PLPGSQL_NSTYPE_LABEL, 0, label);
}


/* ----------
 * plpgsql_ns_pop			Return to the previous level
 * ----------
 */
void
plpgsql_ns_pop(void)
{
	int			i;
	PLpgSQL_ns *old;

	old = ns_current;
	ns_current = old->upper;

	for (i = 0; i < old->items_used; i++)
		pfree(old->items[i]);
	pfree(old->items);
	pfree(old);
}


/* ----------
 * plpgsql_ns_additem			Add an item to the current
 *					namestack level
 * ----------
 */
void
plpgsql_ns_additem(int itemtype, int itemno, const char *name)
{
	PLpgSQL_ns *ns = ns_current;
	PLpgSQL_nsitem *nse;

	Assert(name != NULL);

	if (ns->items_used == ns->items_alloc)
	{
		if (ns->items_alloc == 0)
		{
			ns->items_alloc = 32;
			ns->items = palloc(sizeof(PLpgSQL_nsitem *) * ns->items_alloc);
		}
		else
		{
			ns->items_alloc *= 2;
			ns->items = repalloc(ns->items,
								 sizeof(PLpgSQL_nsitem *) * ns->items_alloc);
		}
	}

	nse = palloc(sizeof(PLpgSQL_nsitem) + strlen(name));
	nse->itemtype = itemtype;
	nse->itemno = itemno;
	strcpy(nse->name, name);
	ns->items[ns->items_used++] = nse;
}


/* ----------
 * plpgsql_ns_lookup			Lookup for a word in the namestack
 * ----------
 */
PLpgSQL_nsitem *
plpgsql_ns_lookup(char *name, char *label)
{
	PLpgSQL_ns *ns;
	int			i;

	/*
	 * If a label is specified, lookup only in that
	 */
	if (label != NULL)
	{
		for (ns = ns_current; ns != NULL; ns = ns->upper)
		{
			if (!strcmp(ns->items[0]->name, label))
			{
				for (i = 1; i < ns->items_used; i++)
				{
					if (!strcmp(ns->items[i]->name, name))
						return ns->items[i];
				}
				return NULL;	/* name not found in specified label */
			}
		}
		return NULL;			/* label not found */
	}

	/*
	 * No label given, lookup for visible labels ignoring localmode
	 */
	for (ns = ns_current; ns != NULL; ns = ns->upper)
	{
		if (!strcmp(ns->items[0]->name, name))
			return ns->items[0];
	}

	/*
	 * Finally lookup name in the namestack
	 */
	for (ns = ns_current; ns != NULL; ns = ns->upper)
	{
		for (i = 1; i < ns->items_used; i++)
		{
			if (!strcmp(ns->items[i]->name, name))
				return ns->items[i];
		}
		if (ns_localmode)
			return NULL;		/* name not found in current namespace */
	}

	return NULL;
}


/* ----------
 * plpgsql_ns_rename			Rename a namespace entry
 * ----------
 */
void
plpgsql_ns_rename(char *oldname, char *newname)
{
	PLpgSQL_ns *ns;
	PLpgSQL_nsitem *newitem;
	int			i;

	/*
	 * Lookup name in the namestack; do the lookup in the current namespace
	 * only.
	 */
	for (ns = ns_current; ns != NULL; ns = ns->upper)
	{
		for (i = 1; i < ns->items_used; i++)
		{
			if (!strcmp(ns->items[i]->name, oldname))
			{
				newitem = palloc(sizeof(PLpgSQL_nsitem) + strlen(newname));
				newitem->itemtype = ns->items[i]->itemtype;
				newitem->itemno = ns->items[i]->itemno;
				strcpy(newitem->name, newname);

				pfree(oldname);
				pfree(newname);

				pfree(ns->items[i]);
				ns->items[i] = newitem;
				return;
			}
		}
	}

	ereport(ERROR,
			(errcode(ERRCODE_UNDEFINED_OBJECT),
			 errmsg("there is no variable \"%s\" in the current block",
					oldname)));
}


/* ----------
 * plpgsql_convert_ident
 *
 * Convert a possibly-qualified identifier to internal form: handle
 * double quotes, translate to lower case where not inside quotes,
 * truncate to NAMEDATALEN.
 *
 * There may be several identifiers separated by dots and optional
 * whitespace.	Each one is converted to a separate palloc'd string.
 * The caller passes the expected number of identifiers, as well as
 * a char* array to hold them.	It is an error if we find the wrong
 * number of identifiers (cf grammar processing of fori_varname).
 *
 * NOTE: the input string has already been accepted by the flex lexer,
 * so we don't need a heckuva lot of error checking here.
 * ----------
 */
void
plpgsql_convert_ident(const char *s, char **output, int numidents)
{
	const char *sstart = s;
	int			identctr = 0;

	/* Outer loop over identifiers */
	while (*s)
	{
		char	   *curident;
		char	   *cp;

		/* Process current identifier */

		if (*s == '"')
		{
			/* Quoted identifier: copy, collapsing out doubled quotes */

			curident = palloc(strlen(s) + 1);	/* surely enough room */
			cp = curident;
			s++;
			while (*s)
			{
				if (*s == '"')
				{
					if (s[1] != '"')
						break;
					s++;
				}
				*cp++ = *s++;
			}
			if (*s != '"')		/* should not happen if lexer checked */
				ereport(ERROR,
						(errcode(ERRCODE_SYNTAX_ERROR),
						 errmsg("unterminated \" in name: %s", sstart)));
			s++;
			*cp = '\0';
			/* Truncate to NAMEDATALEN */
			truncate_identifier(curident, cp - curident, false);
		}
		else
		{
			/* Normal identifier: extends till dot or whitespace */
			const char *thisstart = s;

			while (*s && *s != '.' && !isspace((unsigned char) *s))
				s++;
			/* Downcase and truncate to NAMEDATALEN */
			curident = downcase_truncate_identifier(thisstart, s - thisstart,
													false);
		}

		/* Pass ident to caller */
		if (identctr < numidents)
			output[identctr++] = curident;
		else
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("qualified identifier cannot be used here: %s",
							sstart)));

		/* If not done, skip whitespace, dot, whitespace */
		if (*s)
		{
			while (*s && isspace((unsigned char) *s))
				s++;
			if (*s++ != '.')
				elog(ERROR, "expected dot between identifiers: %s", sstart);
			while (*s && isspace((unsigned char) *s))
				s++;
			if (*s == '\0')
				elog(ERROR, "expected another identifier: %s", sstart);
		}
	}

	if (identctr != numidents)
		elog(ERROR, "improperly qualified identifier: %s",
			 sstart);
}


/*
 * Statement type as a string, for use in error messages etc.
 */
const char *
plpgsql_stmt_typename(PLpgSQL_stmt *stmt)
{
	switch (stmt->cmd_type)
	{
		case PLPGSQL_STMT_BLOCK:
			return "block variables initialization";
		case PLPGSQL_STMT_ASSIGN:
			return "assignment";
		case PLPGSQL_STMT_IF:
			return "if";
		case PLPGSQL_STMT_LOOP:
			return "loop";
		case PLPGSQL_STMT_WHILE:
			return "while";
		case PLPGSQL_STMT_FORI:
			return "for with integer loopvar";
		case PLPGSQL_STMT_FORS:
			return "for over select rows";
		case PLPGSQL_STMT_SELECT:
			return "select into variables";
		case PLPGSQL_STMT_EXIT:
			return "exit";
		case PLPGSQL_STMT_RETURN:
			return "return";
		case PLPGSQL_STMT_RETURN_NEXT:
			return "return next";
		case PLPGSQL_STMT_RAISE:
			return "raise";
		case PLPGSQL_STMT_EXECSQL:
			return "SQL statement";
		case PLPGSQL_STMT_DYNEXECUTE:
			return "execute statement";
		case PLPGSQL_STMT_DYNFORS:
			return "for over execute statement";
		case PLPGSQL_STMT_GETDIAG:
			return "get diagnostics";
		case PLPGSQL_STMT_OPEN:
			return "open";
		case PLPGSQL_STMT_FETCH:
			return "fetch";
		case PLPGSQL_STMT_CLOSE:
			return "close";
		case PLPGSQL_STMT_PERFORM:
			return "perform";
	}

	return "unknown";
}


/**********************************************************************
 * Debug functions for analyzing the compiled code
 **********************************************************************/
static int	dump_indent;

static void dump_ind();
static void dump_stmt(PLpgSQL_stmt *stmt);
static void dump_block(PLpgSQL_stmt_block *block);
static void dump_assign(PLpgSQL_stmt_assign *stmt);
static void dump_if(PLpgSQL_stmt_if *stmt);
static void dump_loop(PLpgSQL_stmt_loop *stmt);
static void dump_while(PLpgSQL_stmt_while *stmt);
static void dump_fori(PLpgSQL_stmt_fori *stmt);
static void dump_fors(PLpgSQL_stmt_fors *stmt);
static void dump_select(PLpgSQL_stmt_select *stmt);
static void dump_exit(PLpgSQL_stmt_exit *stmt);
static void dump_return(PLpgSQL_stmt_return *stmt);
static void dump_return_next(PLpgSQL_stmt_return_next *stmt);
static void dump_raise(PLpgSQL_stmt_raise *stmt);
static void dump_execsql(PLpgSQL_stmt_execsql *stmt);
static void dump_dynexecute(PLpgSQL_stmt_dynexecute *stmt);
static void dump_dynfors(PLpgSQL_stmt_dynfors *stmt);
static void dump_getdiag(PLpgSQL_stmt_getdiag *stmt);
static void dump_open(PLpgSQL_stmt_open *stmt);
static void dump_fetch(PLpgSQL_stmt_fetch *stmt);
static void dump_close(PLpgSQL_stmt_close *stmt);
static void dump_perform(PLpgSQL_stmt_perform *stmt);
static void dump_expr(PLpgSQL_expr *expr);


static void
dump_ind(void)
{
	int			i;

	for (i = 0; i < dump_indent; i++)
		printf(" ");
}

static void
dump_stmt(PLpgSQL_stmt *stmt)
{
	printf("%3d:", stmt->lineno);
	switch (stmt->cmd_type)
	{
		case PLPGSQL_STMT_BLOCK:
			dump_block((PLpgSQL_stmt_block *) stmt);
			break;
		case PLPGSQL_STMT_ASSIGN:
			dump_assign((PLpgSQL_stmt_assign *) stmt);
			break;
		case PLPGSQL_STMT_IF:
			dump_if((PLpgSQL_stmt_if *) stmt);