dumputils.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

/*-------------------------------------------------------------------------
 *
 * Utility routines for SQL dumping
 *	Basically this is stuff that is useful in both pg_dump and pg_dumpall.
 *
 *
 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $PostgreSQL: pgsql/src/bin/pg_dump/dumputils.c,v 1.20.2.1 2005/11/22 18:23:26 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "postgres_fe.h"

#include "dumputils.h"

#include "parser/keywords.h"


#define supports_grant_options(version) ((version) >= 70400)

static bool parseAclItem(const char *item, const char *type, const char *name,
			 int remoteVersion,
			 PQExpBuffer grantee, PQExpBuffer grantor,
			 PQExpBuffer privs, PQExpBuffer privswgo);
static char *copyAclUserName(PQExpBuffer output, char *input);
static void AddAcl(PQExpBuffer aclbuf, const char *keyword);


/*
 *	Quotes input string if it's not a legitimate SQL identifier as-is.
 *
 *	Note that the returned string must be used before calling fmtId again,
 *	since we re-use the same return buffer each time.  Non-reentrant but
 *	avoids memory leakage.
 */
const char *
fmtId(const char *rawid)
{
	static PQExpBuffer id_return = NULL;
	const char *cp;
	bool		need_quotes = false;

	if (id_return)				/* first time through? */
		resetPQExpBuffer(id_return);
	else
		id_return = createPQExpBuffer();

	/*
	 * These checks need to match the identifier production in scan.l. Don't
	 * use islower() etc.
	 */

	if (ScanKeywordLookup(rawid))
		need_quotes = true;
	/* slightly different rules for first character */
	else if (!((rawid[0] >= 'a' && rawid[0] <= 'z') || rawid[0] == '_'))
		need_quotes = true;
	else
	{
		/* otherwise check the entire string */
		for (cp = rawid; *cp; cp++)
		{
			if (!((*cp >= 'a' && *cp <= 'z')
				  || (*cp >= '0' && *cp <= '9')
				  || (*cp == '_')))
			{
				need_quotes = true;
				break;
			}
		}
	}

	if (!need_quotes)
	{
		/* no quoting needed */
		appendPQExpBufferStr(id_return, rawid);
	}
	else
	{
		appendPQExpBufferChar(id_return, '\"');
		for (cp = rawid; *cp; cp++)
		{
			/*
			 * Did we find a double-quote in the string? Then make this a
			 * double double-quote per SQL99. Before, we put in a
			 * backslash/double-quote pair. - thomas 2000-08-05
			 */
			if (*cp == '\"')
				appendPQExpBufferChar(id_return, '\"');
			appendPQExpBufferChar(id_return, *cp);
		}
		appendPQExpBufferChar(id_return, '\"');
	}

	return id_return->data;
}


/*
 * Convert a string value to an SQL string literal and append it to
 * the given buffer.
 *
 * Special characters are escaped. Quote mark ' goes to '' per SQL
 * standard, other stuff goes to \ sequences.  If escapeAll is false,
 * whitespace characters are not escaped (tabs, newlines, etc.).  This
 * is appropriate for dump file output.
 */
void
appendStringLiteral(PQExpBuffer buf, const char *str, bool escapeAll)
{
	char		ch;
	const char *p;

	for (p = str; *p; p++)
	{
		ch = *p;
		if (ch == '\\' ||
			((unsigned char) ch < (unsigned char) ' ' &&
			 (escapeAll ||
			  (ch != '\t' && ch != '\n' && ch != '\v' &&
			   ch != '\f' && ch != '\r'))))
		{
			appendPQExpBufferChar(buf, ESCAPE_STRING_SYNTAX);
			break;
		}
	}

	appendPQExpBufferChar(buf, '\'');
	for (p = str; *p; p++)
	{
		ch = *p;
		if (SQL_STR_DOUBLE(ch))
		{
			appendPQExpBufferChar(buf, ch);
			appendPQExpBufferChar(buf, ch);
		}
		else if ((unsigned char) ch < (unsigned char) ' ' &&
				 (escapeAll ||
				  (ch != '\t' && ch != '\n' && ch != '\v' &&
				   ch != '\f' && ch != '\r')))
		{
			/*
			 * generate octal escape for control chars other than whitespace
			 */
			appendPQExpBufferChar(buf, '\\');
			appendPQExpBufferChar(buf, ((ch >> 6) & 3) + '0');
			appendPQExpBufferChar(buf, ((ch >> 3) & 7) + '0');
			appendPQExpBufferChar(buf, (ch & 7) + '0');
		}
		else
			appendPQExpBufferChar(buf, ch);
	}
	appendPQExpBufferChar(buf, '\'');
}


/*
 * Convert a string value to a dollar quoted literal and append it to
 * the given buffer. If the dqprefix parameter is not NULL then the
 * dollar quote delimiter will begin with that (after the opening $).
 *
 * No escaping is done at all on str, in compliance with the rules
 * for parsing dollar quoted strings.
 */
void
appendStringLiteralDQ(PQExpBuffer buf, const char *str, const char *dqprefix)
{
	static const char suffixes[] = "_XXXXXXX";
	int			nextchar = 0;
	PQExpBuffer delimBuf = createPQExpBuffer();

	/* start with $ + dqprefix if not NULL */
	appendPQExpBufferChar(delimBuf, '$');
	if (dqprefix)
		appendPQExpBufferStr(delimBuf, dqprefix);

	/*
	 * Make sure we choose a delimiter which (without the trailing $) is not
	 * present in the string being quoted. We don't check with the trailing $
	 * because a string ending in $foo must not be quoted with $foo$.
	 */
	while (strstr(str, delimBuf->data) != NULL)
	{
		appendPQExpBufferChar(delimBuf, suffixes[nextchar++]);
		nextchar %= sizeof(suffixes) - 1;
	}

	/* add trailing $ */
	appendPQExpBufferChar(delimBuf, '$');

	/* quote it and we are all done */
	appendPQExpBufferStr(buf, delimBuf->data);
	appendPQExpBufferStr(buf, str);
	appendPQExpBufferStr(buf, delimBuf->data);

	destroyPQExpBuffer(delimBuf);
}


/*
 * Use dollar quoting if the string to be quoted contains ' or \,
 * otherwise use standard quoting.
 */
void
appendStringLiteralDQOpt(PQExpBuffer buf, const char *str,
						 bool escapeAll, const char *dqprefix)
{
	if (strchr(str, '\'') == NULL && strchr(str, '\\') == NULL)
		appendStringLiteral(buf, str, escapeAll);
	else
		appendStringLiteralDQ(buf, str, dqprefix);
}


/*
 * Convert backend's version string into a number.
 */
int
parse_version(const char *versionString)
{
	int			cnt;
	int			vmaj,
				vmin,
				vrev;

	cnt = sscanf(versionString, "%d.%d.%d", &vmaj, &vmin, &vrev);

	if (cnt < 2)
		return -1;

	if (cnt == 2)
		vrev = 0;

	return (100 * vmaj + vmin) * 100 + vrev;
}


/*
 * Deconstruct the text representation of a 1-dimensional Postgres array
 * into individual items.
 *
 * On success, returns true and sets *itemarray and *nitems to describe
 * an array of individual strings.	On parse failure, returns false;
 * *itemarray may exist or be NULL.
 *
 * NOTE: free'ing itemarray is sufficient to deallocate the working storage.
 */
bool
parsePGArray(const char *atext, char ***itemarray, int *nitems)
{
	int			inputlen;
	char	  **items;
	char	   *strings;
	int			curitem;

	/*
	 * We expect input in the form of "{item,item,item}" where any item is
	 * either raw data, or surrounded by double quotes (in which case embedded
	 * characters including backslashes and quotes are backslashed).
	 *
	 * We build the result as an array of pointers followed by the actual
	 * string data, all in one malloc block for convenience of deallocation.
	 * The worst-case storage need is not more than one pointer and one
	 * character for each input character (consider "{,,,,,,,,,,}").
	 */
	*itemarray = NULL;
	*nitems = 0;
	inputlen = strlen(atext);
	if (inputlen < 2 || atext[0] != '{' || atext[inputlen - 1] != '}')
		return false;			/* bad input */
	items = (char **) malloc(inputlen * (sizeof(char *) + sizeof(char)));
	if (items == NULL)
		return false;			/* out of memory */
	*itemarray = items;
	strings = (char *) (items + inputlen);

	atext++;					/* advance over initial '{' */
	curitem = 0;
	while (*atext != '}')
	{
		if (*atext == '\0')
			return false;		/* premature end of string */
		items[curitem] = strings;
		while (*atext != '}' && *atext != ',')
		{
			if (*atext == '\0')
				return false;	/* premature end of string */
			if (*atext != '"')
				*strings++ = *atext++;	/* copy unquoted data */
			else
			{
				/* process quoted substring */
				atext++;
				while (*atext != '"')
				{
					if (*atext == '\0')
						return false;	/* premature end of string */
					if (*atext == '\\')
					{
						atext++;
						if (*atext == '\0')
							return false;		/* premature end of string */
					}
					*strings++ = *atext++;		/* copy quoted data */
				}
				atext++;
			}
		}
		*strings++ = '\0';
		if (*atext == ',')
			atext++;
		curitem++;
	}
	if (atext[1] != '\0')
		return false;			/* bogus syntax (embedded '}') */
	*nitems = curitem;
	return true;
}


/*
 * Build GRANT/REVOKE command(s) for an object.
 *
 *	name: the object name, in the form to use in the commands (already quoted)
 *	type: the object type (as seen in GRANT command: must be one of
 *		TABLE, FUNCTION, LANGUAGE, or SCHEMA, or DATABASE)
 *	acls: the ACL string fetched from the database
 *	owner: username of object owner (will be passed through fmtId), or NULL
 *	remoteVersion: version of database
 *
 * Returns TRUE if okay, FALSE if could not parse the acl string.
 * The resulting commands (if any) are appended to the contents of 'sql'.
 *
 * Note: beware of passing fmtId() result as 'name', since this routine