/*
 * Check whether the specified command is a SELECT (or VALUES).
 */
static bool
is_select_command(const char *query)
{
	int			wordlen;

	/*
	 * First advance over any whitespace, comments and left parentheses.
	 */
	for (;;)
	{
		query = skip_white_space(query);
		if (query[0] == '(')
			query++;
		else
			break;
	}

	/*
	 * Check word length (since "selectx" is not "select").
	 */
	wordlen = 0;
	while (isalpha((unsigned char) query[wordlen]))
		wordlen += PQmblen(&query[wordlen], pset.encoding);

	if (wordlen == 6 && pg_strncasecmp(query, "select", 6) == 0)
		return true;

	if (wordlen == 6 && pg_strncasecmp(query, "values", 6) == 0)
		return true;

	return false;
}

/*
 * equivalent_locale()
 *
 * Best effort locale-name comparison.  Return false if we are not 100% sure
 * the locales are equivalent.
 */
static bool
equivalent_locale(const char *loca, const char *locb)
{
	const char *chara = strrchr(loca, '.');
	const char *charb = strrchr(locb, '.');
	int			lencmp;

	/* If they don't both contain an encoding part, just do strcasecmp(). */
	if (!chara || !charb)
		return (pg_strcasecmp(loca, locb) == 0);

	/*
	 * Compare the encoding parts.	Windows tends to use code page numbers for
	 * the encoding part, which equivalent_encoding() won't like, so accept if
	 * the strings are case-insensitive equal; otherwise use
	 * equivalent_encoding() to compare.
	 */
	if (pg_strcasecmp(chara + 1, charb + 1) != 0 &&
		!equivalent_encoding(chara + 1, charb + 1))
		return false;

	/*
	 * OK, compare the locale identifiers (e.g. en_US part of en_US.utf8).
	 *
	 * It's tempting to ignore non-alphanumeric chars here, but for now it's
	 * not clear that that's necessary; just do case-insensitive comparison.
	 */
	lencmp = chara - loca;
	if (lencmp != charb - locb)
		return false;

	return (pg_strncasecmp(loca, locb, lencmp) == 0);
}

/*
 * equivalent_locale()
 *
 * Best effort locale-name comparison.  Return false if we are not 100% sure
 * the locales are equivalent.
 *
 * Note: The encoding parts of the names are ignored. This function is
 * currently used to compare locale names stored in pg_database, and
 * pg_database contains a separate encoding field. That's compared directly
 * in check_locale_and_encoding().
 */
static bool
equivalent_locale(int category, const char *loca, const char *locb)
{
	const char *chara;
	const char *charb;
	char	   *canona;
	char	   *canonb;
	int			lena;
	int			lenb;

	/*
	 * If the names are equal, the locales are equivalent. Checking this
	 * first avoids calling setlocale() in the common case that the names
	 * are equal. That's a good thing, if setlocale() is buggy, for example.
	 */
	if (pg_strcasecmp(loca, locb) == 0)
		return true;

	/*
	 * Not identical. Canonicalize both names, remove the encoding parts,
	 * and try again.
	 */
	canona = get_canonical_locale_name(category, loca);
	chara = strrchr(canona, '.');
	lena = chara ? (chara - canona) : strlen(canona);

	canonb = get_canonical_locale_name(category, locb);
	charb = strrchr(canonb, '.');
	lenb = charb ? (charb - canonb) : strlen(canonb);

	if (lena == lenb && pg_strncasecmp(canona, canonb, lena) == 0)
		return true;

	return false;
}

/**
 * complete_from_list()
 *
 * Returns one of a fixed, NULL pointer terminated list of strings (if matching)
 * in their defined order. This can be used if there are only a fixed number of
 * SQL words that can appear at certain spot.
 */
static char *
complete_from_list(const char *text, int state)
{
	static int	string_length,
				list_index,
				matches;
	static bool casesensitive;
	const char *item;

	/* Initialization */
	if (state == 0)
	{
		list_index = 0;
		string_length = strlen(text);
		casesensitive = completion_case_sensitive;
		matches = 0;
	}

	while ((item = completion_charpp[list_index++]))
	{
		/* First pass is case sensitive */
		if (casesensitive && strncmp(text, item, string_length) == 0)
		{
			matches++;
			return strdup(item);
		}

		/* Second pass is case insensitive, don't bother counting matches */
		if (!casesensitive && pg_strncasecmp(text, item, string_length) == 0)
		{
			if (completion_case_sensitive)
				return strdup(item);
			else

				/*
				 * If case insensitive matching was requested initially,
				 * adjust the case according to setting.
				 */
				return fb_strdup_keyword_case(item, text);

		}
	}

	/*
	 * No matches found. If we're not case insensitive already, lets switch to
	 * being case insensitive and try again
	 */
	if (casesensitive && matches == 0)
	{
		casesensitive = false;
		list_index = 0;
		state++;
		return complete_from_list(text, state);
	}

	/* If no more matches, return null. */
	return NULL;
}

/*
 * Try to interpret value as boolean value.  Valid values are: true,
 * false, yes, no, on, off, 1, 0; as well as unique prefixes thereof.
 */
bool
ParseVariableBool(const char *value)
{
	size_t		len;

	if (value == NULL)
		return false;			/* not set -> assume "off" */

	len = strlen(value);

	if (pg_strncasecmp(value, "true", len) == 0)
		return true;
	else if (pg_strncasecmp(value, "false", len) == 0)
		return false;
	else if (pg_strncasecmp(value, "yes", len) == 0)
		return true;
	else if (pg_strncasecmp(value, "no", len) == 0)
		return false;
	/* 'o' is not unique enough */
	else if (pg_strncasecmp(value, "on", (len > 2 ? len : 2)) == 0)
		return true;
	else if (pg_strncasecmp(value, "off", (len > 2 ? len : 2)) == 0)
		return false;
	else if (pg_strcasecmp(value, "1") == 0)
		return true;
	else if (pg_strcasecmp(value, "0") == 0)
		return false;
	else
	{
		/* NULL is treated as false, so a non-matching value is 'true' */
		psql_error("unrecognized Boolean value; assuming \"on\"\n");
		return true;
	}
}

/*
 * Transform a relation options list (list of DefElem) into the text array
 * format that is kept in pg_class.reloptions.
 *
 * This is used for three cases: CREATE TABLE/INDEX, ALTER TABLE SET, and
 * ALTER TABLE RESET.  In the ALTER cases, oldOptions is the existing
 * reloptions value (possibly NULL), and we replace or remove entries
 * as needed.
 *
 * If ignoreOids is true, then we should ignore any occurrence of "oids"
 * in the list (it will be or has been handled by interpretOidsOption()).
 *
 * Note that this is not responsible for determining whether the options
 * are valid.
 *
 * Both oldOptions and the result are text arrays (or NULL for "default"),
 * but we declare them as Datums to avoid including array.h in reloptions.h.
 */
Datum
transformRelOptions(Datum oldOptions, List *defList,
					bool ignoreOids, bool isReset)
{
	Datum		result;
	ArrayBuildState *astate;
	ListCell   *cell;

	/* no change if empty list */
	if (defList == NIL)
		return oldOptions;

	/* We build new array using accumArrayResult */
	astate = NULL;

	/* Copy any oldOptions that aren't to be replaced */
	if (DatumGetPointer(oldOptions) != 0)
	{
		ArrayType  *array = DatumGetArrayTypeP(oldOptions);
		Datum	   *oldoptions;
		int			noldoptions;
		int			i;

		Assert(ARR_ELEMTYPE(array) == TEXTOID);

		deconstruct_array(array, TEXTOID, -1, false, 'i',
						  &oldoptions, NULL, &noldoptions);

		for (i = 0; i < noldoptions; i++)
		{
			text	   *oldoption = DatumGetTextP(oldoptions[i]);
			char	   *text_str = VARDATA(oldoption);
			int			text_len = VARSIZE(oldoption) - VARHDRSZ;

			/* Search for a match in defList */
			foreach(cell, defList)
			{
				DefElem    *def = lfirst(cell);
				int			kw_len = strlen(def->defname);

				if (text_len > kw_len && text_str[kw_len] == '=' &&
					pg_strncasecmp(text_str, def->defname, kw_len) == 0)
					break;
			}
			if (!cell)
			{
				/* No match, so keep old option */
				astate = accumArrayResult(astate, oldoptions[i],
										  false, TEXTOID,
										  CurrentMemoryContext);
			}
		}

static void
SpecialTags(TParser * prs)
{
	switch (prs->state->lencharlexeme)
	{
		case 8:			/* </script */
			if (pg_strncasecmp(prs->lexeme, "</script", 8) == 0)
				prs->ignore = false;
			break;
		case 7:			/* <script || </style */
			if (pg_strncasecmp(prs->lexeme, "</style", 7) == 0)
				prs->ignore = false;
			else if (pg_strncasecmp(prs->lexeme, "<script", 7) == 0)
				prs->ignore = true;
			break;
		case 6:			/* <style */
			if (pg_strncasecmp(prs->lexeme, "<style", 6) == 0)
				prs->ignore = true;
			break;
		default:
			break;
	}
}

static int
weekday_search(const WeekDays *weekdays, const char *str, int len)
{
	int		i;

	for (i = 0; i < 7; i++)
	{
		int	n = strlen(weekdays->names[i]);
		if (n > len)
			continue;	/* too short */
		if (pg_strncasecmp(weekdays->names[i], str, n) == 0)
			return i;
	}
	return -1;	/* not found */
}

static bool
check_special_value(char *ptr, double *retval, char **endptr)
{
	if (pg_strncasecmp(ptr, "NaN", 3) == 0)
	{
		*retval = get_float8_nan();
		*endptr = ptr + 3;
		return true;
	}
	else if (pg_strncasecmp(ptr, "Infinity", 8) == 0)
	{
		*retval = get_float8_infinity();
		*endptr = ptr + 8;
		return true;
	}
	else if (pg_strncasecmp(ptr, "-Infinity", 9) == 0)
	{
		*retval = -get_float8_infinity();
		*endptr = ptr + 9;
		return true;
	}

	return false;
}

static int
ora_seq_prefix_search(const char *name, STRING_PTR_FIELD_TYPE array[], int max)
{
	int		i;

	if (!*name)
		return -1;

	for (i = 0; array[i]; i++)
	{
		if (pg_strncasecmp(name, array[i], max) == 0)
			return i;
	}
	return -1;	/* not found */
}

relopt_value *
get_option_set(relopt_value *options, int num_options, const char *opt_name)
{
	int			i;
	int			opt_name_len;
	int			cmp_len;

	opt_name_len = strlen(opt_name);
	for (i = 0; i < num_options; ++i)
	{
		cmp_len = options[i].gen->namelen > opt_name_len ? opt_name_len : options[i].gen->namelen;
		if (options[i].isset && pg_strncasecmp(options[i].gen->name, opt_name, cmp_len) == 0)
			return &options[i];
	}
	return NULL;
}

/**
 * complete_from_query()
 *
 * Dynamically generate tab completion candidates from the specified query
 */
static char *
complete_from_query(const char *text, int state)
{
	static int	list_index,
				string_length;
	static FBresult *result = NULL;
	char			*query;

	if (state == 0)
	{
		string_length = strlen(text);
		list_index = 0;

		query = malloc(strlen(completion_charp) * 2 + 1);

		if (completion_info_charp != NULL)
		{
			sprintf(query, completion_charp, string_length, text, completion_info_charp);
		}
		else
		{
			sprintf(query, completion_charp, string_length, text);
		}

		result = FQexecTransaction(fset.conn, query);

		free(query);
	}

	/* Find something that matches */
	if (result && FQresultStatus(result) == FBRES_TUPLES_OK)
	{
		const char *item;
		while (list_index < FQntuples(result) &&
			   (item = FQgetvalue(result, list_index++, 0)))
		{
			if (pg_strncasecmp(text, item, string_length) == 0)
				return strdup(item);
		}
	}

	FQclear(result);
	result = NULL;
	return NULL;
}

/*
 * scan_pl specified directory for a case-insensitive match to fname
 * (of length fnamelen --- fname may not be null terminated!).	If found,
 * copy the actual filename into canonname and return true.
 */
static bool
scan_directory_ci(
	const char *dirname,
	const char *fname,
	int fnamelen,
	char *canonname,
	int canonnamelen)
{
	bool found = false;
	DIR* dirdesc;
	struct dirent *direntry;

	dirdesc = alloc_dir(dirname);
	if (!dirdesc) {
		ereport(LOG, (
		errcode_file_access(),
		errmsg("could not open directory \"%s\": %m", dirname)));

		return false;
	}

	while ((direntry = read_dir(dirdesc, dirname)) != NULL) {
		/*
		 * Ignore . and .., plus any other "hidden" files.	This is a security
		 * measure to prevent access to files outside the timezone directory.
		 */
		if (direntry->d_name[0] == '.')
			continue;

		if (strlen(direntry->d_name) == fnamelen
			&& pg_strncasecmp(direntry->d_name, fname, fnamelen) == 0) {
			/* Found our match */
			strlcpy(canonname, direntry->d_name, canonnamelen);
			found = true;
			break;
		}
	}

	free_dir(dirdesc);

	return found;
}

/**
 * create_or_drop_keyword_generator()
 *
 * List of keywords which can follow CREATE or DROP
 */
static char *
create_or_drop_keyword_generator(const char *text, int state)
{
	static int	list_index,
				string_length;
	const char *name;

	/* If this is the first time for this completion, init some values */
	if (state == 0)
	{
		list_index = 0;
		string_length = strlen(text);
	}

	/* find something that matches */
	while ((name = words_after_create[list_index++].name))
	{
		if (pg_strncasecmp(name, text, string_length) == 0)
			return fb_strdup_keyword_case(name, text);
	}
	/* if nothing matches, return NULL */
	return NULL;
}

/*
 * Try to interpret "value" as a boolean value, and if successful,
 * store it in *result.  Otherwise don't clobber *result.
 *
 * Valid values are: true, false, yes, no, on, off, 1, 0; as well as unique
 * prefixes thereof.
 *
 * "name" is the name of the variable we're assigning to, to use in error
 * report if any.  Pass name == NULL to suppress the error report.
 *
 * Return true when "value" is syntactically valid, false otherwise.
 */
bool
ParseVariableBool(const char *value, const char *name, bool *result)
{
	size_t		len;
	bool		valid = true;

	/* Treat "unset" as an empty string, which will lead to error below */
	if (value == NULL)
		value = "";

	len = strlen(value);

	if (len > 0 && pg_strncasecmp(value, "true", len) == 0)
		*result = true;
	else if (len > 0 && pg_strncasecmp(value, "false", len) == 0)
		*result = false;
	else if (len > 0 && pg_strncasecmp(value, "yes", len) == 0)
		*result = true;
	else if (len > 0 && pg_strncasecmp(value, "no", len) == 0)
		*result = false;
	/* 'o' is not unique enough */
	else if (pg_strncasecmp(value, "on", (len > 2 ? len : 2)) == 0)
		*result = true;
	else if (pg_strncasecmp(value, "off", (len > 2 ? len : 2)) == 0)
		*result = false;
	else if (pg_strcasecmp(value, "1") == 0)
		*result = true;
	else if (pg_strcasecmp(value, "0") == 0)
		*result = false;
	else
	{
		/* string is not recognized; don't clobber *result */
		if (name)
			psql_error("unrecognized value \"%s\" for \"%s\": boolean expected\n",
					   value, name);
		valid = false;
	}
	return valid;
}

/*
 * assign_datestyle: GUC assign_hook for datestyle
 */
const char *
assign_datestyle(const char *value, bool doit, GucSource source)
{
	int			newDateStyle = DateStyle;
	int			newDateOrder = DateOrder;
	bool		have_style = false;
	bool		have_order = false;
	bool		ok = true;
	char	   *rawstring;
	char	   *result;
	List	   *elemlist;
	ListCell   *l;

	/* Need a modifiable copy of string */
	rawstring = pstrdup(value);

	/* Parse string into list of identifiers */
	if (!SplitIdentifierString(rawstring, ',', &elemlist))
	{
		/* syntax error in list */
		pfree(rawstring);
		list_free(elemlist);
		ereport(GUC_complaint_elevel(source),
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				 errmsg("invalid list syntax for parameter \"datestyle\"")));
		return NULL;
	}

	foreach(l, elemlist)
	{
		char	   *tok = (char *) lfirst(l);

		/* Ugh. Somebody ought to write a table driven version -- mjl */

		if (pg_strcasecmp(tok, "ISO") == 0)
		{
			if (have_style && newDateStyle != USE_ISO_DATES)
				ok = false;		/* conflicting styles */
			newDateStyle = USE_ISO_DATES;
			have_style = true;
		}
		else if (pg_strcasecmp(tok, "SQL") == 0)
		{
			if (have_style && newDateStyle != USE_SQL_DATES)
				ok = false;		/* conflicting styles */
			newDateStyle = USE_SQL_DATES;
			have_style = true;
		}
		else if (pg_strncasecmp(tok, "POSTGRES", 8) == 0)
		{
			if (have_style && newDateStyle != USE_POSTGRES_DATES)
				ok = false;		/* conflicting styles */
			newDateStyle = USE_POSTGRES_DATES;
			have_style = true;
		}
		else if (pg_strcasecmp(tok, "GERMAN") == 0)
		{
			if (have_style && newDateStyle != USE_GERMAN_DATES)
				ok = false;		/* conflicting styles */
			newDateStyle = USE_GERMAN_DATES;
			have_style = true;
			/* GERMAN also sets DMY, unless explicitly overridden */
			if (!have_order)
				newDateOrder = DATEORDER_DMY;
		}
		else if (pg_strcasecmp(tok, "YMD") == 0)
		{
			if (have_order && newDateOrder != DATEORDER_YMD)
				ok = false;		/* conflicting orders */
			newDateOrder = DATEORDER_YMD;
			have_order = true;
		}
		else if (pg_strcasecmp(tok, "DMY") == 0 ||
				 pg_strncasecmp(tok, "EURO", 4) == 0)
		{
			if (have_order && newDateOrder != DATEORDER_DMY)
				ok = false;		/* conflicting orders */
			newDateOrder = DATEORDER_DMY;
			have_order = true;
		}
		else if (pg_strcasecmp(tok, "MDY") == 0 ||
				 pg_strcasecmp(tok, "US") == 0 ||
				 pg_strncasecmp(tok, "NONEURO", 7) == 0)
		{
			if (have_order && newDateOrder != DATEORDER_MDY)
				ok = false;		/* conflicting orders */
			newDateOrder = DATEORDER_MDY;
			have_order = true;
		}
		else if (pg_strcasecmp(tok, "DEFAULT") == 0)
		{
			/*
			 * Easiest way to get the current DEFAULT state is to fetch the
			 * DEFAULT string from guc.c and recursively parse it.
			 *
			 * We can't simply "return assign_datestyle(...)" because we need
			 * to handle constructs like "DEFAULT, ISO".
//.........这里部分代码省略.........

static void
doCustom(CState * state, int n, int debug)
{
	PGresult   *res;
	CState	   *st = &state[n];
	Command   **commands;

top:
	commands = sql_files[st->use_file];

	if (st->listen)
	{							/* are we receiver? */
		if (commands[st->state]->type == SQL_COMMAND)
		{
			if (debug)
				fprintf(stderr, "client %d receiving\n", n);
			if (!PQconsumeInput(st->con))
			{					/* there's something wrong */
				fprintf(stderr, "Client %d aborted in state %d. Probably the backend died while processing.\n", n, st->state);
				remains--;		/* I've aborted */
				PQfinish(st->con);
				st->con = NULL;
				return;
			}
			if (PQisBusy(st->con))
				return;			/* don't have the whole result yet */
		}

		/*
		 * transaction finished: record the time it took in the log
		 */
		if (use_log && commands[st->state + 1] == NULL)
		{
			double		diff;
			struct timeval now;

			gettimeofday(&now, NULL);
			diff = (int) (now.tv_sec - st->txn_begin.tv_sec) * 1000000.0 +
				(int) (now.tv_usec - st->txn_begin.tv_usec);

			fprintf(LOGFILE, "%d %d %.0f\n", st->id, st->cnt, diff);
		}

		if (commands[st->state]->type == SQL_COMMAND)
		{
			res = PQgetResult(st->con);
			if (pg_strncasecmp(commands[st->state]->argv[0], "select", 6) != 0)
			{
				if (check(state, res, n, PGRES_COMMAND_OK))
					return;
			}
			else
			{
				if (check(state, res, n, PGRES_TUPLES_OK))
					return;
			}
			PQclear(res);
			discard_response(st);
		}

		if (commands[st->state + 1] == NULL)
		{
			if (is_connect)
			{
				PQfinish(st->con);
				st->con = NULL;
			}

			if (++st->cnt >= nxacts)
			{
				remains--;		/* I've done */
				if (st->con != NULL)
				{
					PQfinish(st->con);
					st->con = NULL;
				}
				return;
			}
		}

		/* increment state counter */
		st->state++;
		if (commands[st->state] == NULL)
		{
			st->state = 0;
			st->use_file = getrand(0, num_files - 1);
			commands = sql_files[st->use_file];
		}
	}

	if (st->con == NULL)
	{
		if ((st->con = doConnect()) == NULL)
		{
			fprintf(stderr, "Client %d aborted in establishing connection.\n",
					n);
			remains--;			/* I've aborted */
			PQfinish(st->con);
			st->con = NULL;
			return;
//.........这里部分代码省略.........

/*
 * Check whether a command is one of those for which we should NOT start
 * a new transaction block (ie, send a preceding BEGIN).
 *
 * These include the transaction control statements themselves, plus
 * certain statements that the backend disallows inside transaction blocks.
 */
static bool
command_no_begin(const char *query)
{
	int			wordlen;

	/*
	 * First we must advance over any whitespace and comments.
	 */
	query = skip_white_space(query);

	/*
	 * Check word length (since "beginx" is not "begin").
	 */
	wordlen = 0;
	while (isalpha((unsigned char) query[wordlen]))
		wordlen += PQmblen(&query[wordlen], pset.encoding);

	/*
	 * Transaction control commands.  These should include every keyword that
	 * gives rise to a TransactionStmt in the backend grammar, except for the
	 * savepoint-related commands.
	 *
	 * (We assume that START must be START TRANSACTION, since there is
	 * presently no other "START foo" command.)
	 */
	if (wordlen == 5 && pg_strncasecmp(query, "abort", 5) == 0)
		return true;
	if (wordlen == 5 && pg_strncasecmp(query, "begin", 5) == 0)
		return true;
	if (wordlen == 5 && pg_strncasecmp(query, "start", 5) == 0)
		return true;
	if (wordlen == 6 && pg_strncasecmp(query, "commit", 6) == 0)
		return true;
	if (wordlen == 3 && pg_strncasecmp(query, "end", 3) == 0)
		return true;
	if (wordlen == 8 && pg_strncasecmp(query, "rollback", 8) == 0)
		return true;
	if (wordlen == 7 && pg_strncasecmp(query, "prepare", 7) == 0)
	{
		/* PREPARE TRANSACTION is a TC command, PREPARE foo is not */
		query += wordlen;

		query = skip_white_space(query);

		wordlen = 0;
		while (isalpha((unsigned char) query[wordlen]))
			wordlen += PQmblen(&query[wordlen], pset.encoding);

		if (wordlen == 11 && pg_strncasecmp(query, "transaction", 11) == 0)
			return true;
		return false;
	}

	/*
	 * Commands not allowed within transactions.  The statements checked for
	 * here should be exactly those that call PreventTransactionChain() in the
	 * backend.
	 */
	if (wordlen == 6 && pg_strncasecmp(query, "vacuum", 6) == 0)
		return true;
	if (wordlen == 7 && pg_strncasecmp(query, "cluster", 7) == 0)
	{
		/* CLUSTER with any arguments is allowed in transactions */
		query += wordlen;

		query = skip_white_space(query);

		if (isalpha((unsigned char) query[0]))
			return false;		/* has additional words */
		return true;			/* it's CLUSTER without arguments */
	}

	if (wordlen == 6 && pg_strncasecmp(query, "create", 6) == 0)
	{
		query += wordlen;

		query = skip_white_space(query);

		wordlen = 0;
		while (isalpha((unsigned char) query[wordlen]))
			wordlen += PQmblen(&query[wordlen], pset.encoding);

		if (wordlen == 8 && pg_strncasecmp(query, "database", 8) == 0)
			return true;
		if (wordlen == 10 && pg_strncasecmp(query, "tablespace", 10) == 0)
			return true;

		/* CREATE [UNIQUE] INDEX CONCURRENTLY isn't allowed in xacts */
		if (wordlen == 6 && pg_strncasecmp(query, "unique", 6) == 0)
		{
			query += wordlen;

			query = skip_white_space(query);
//.........这里部分代码省略.........

bool
do_pset(const char *param, const char *value, printQueryOpt *popt, bool quiet)
{
	size_t		vallen = 0;

	psql_assert(param);

	if (value)
		vallen = strlen(value);

	/* set format */
	if (strcmp(param, "format") == 0)
	{
		if (!value)
			;
		else if (pg_strncasecmp("unaligned", value, vallen) == 0)
			popt->topt.format = PRINT_UNALIGNED;
		else if (pg_strncasecmp("aligned", value, vallen) == 0)
			popt->topt.format = PRINT_ALIGNED;
		else if (pg_strncasecmp("wrapped", value, vallen) == 0)
			popt->topt.format = PRINT_WRAPPED;
		else if (pg_strncasecmp("html", value, vallen) == 0)
			popt->topt.format = PRINT_HTML;
		else if (pg_strncasecmp("latex", value, vallen) == 0)
			popt->topt.format = PRINT_LATEX;
		else if (pg_strncasecmp("troff-ms", value, vallen) == 0)
			popt->topt.format = PRINT_TROFF_MS;
		else
		{
			psql_error("\\pset: allowed formats are unaligned, aligned, wrapped, html, latex, troff-ms\n");
			return false;
		}

		if (!quiet)
			printf(_("Output format is %s.\n"), _align2string(popt->topt.format));
	}

	/* set table line style */
	else if (strcmp(param, "linestyle") == 0)
	{
		if (!value)
			;
		else if (pg_strncasecmp("ascii", value, vallen) == 0)
			popt->topt.line_style = &pg_asciiformat;
		else if (pg_strncasecmp("old-ascii", value, vallen) == 0)
			popt->topt.line_style = &pg_asciiformat_old;
		else if (pg_strncasecmp("unicode", value, vallen) == 0)
			popt->topt.line_style = &pg_utf8format;
		else
		{
			psql_error("\\pset: allowed line styles are ascii, old-ascii, unicode\n");
			return false;
		}

		if (!quiet)
			printf(_("Line style is %s.\n"),
				   get_line_style(&popt->topt)->name);
	}

	/* set border style/width */
	else if (strcmp(param, "border") == 0)
	{
		if (value)
			popt->topt.border = atoi(value);

		if (!quiet)
			printf(_("Border style is %d.\n"), popt->topt.border);
	}

	/* set expanded/vertical mode */
	else if (strcmp(param, "x") == 0 || strcmp(param, "expanded") == 0 || strcmp(param, "vertical") == 0)
	{
		if (value)
			popt->topt.expanded = ParseVariableBool(value);
		else
			popt->topt.expanded = !popt->topt.expanded;
		if (!quiet)
			printf(popt->topt.expanded
				   ? _("Expanded display is on.\n")
				   : _("Expanded display is off.\n"));
	}

	/* locale-aware numeric output */
	else if (strcmp(param, "numericlocale") == 0)
	{
		if (value)
			popt->topt.numericLocale = ParseVariableBool(value);
		else
			popt->topt.numericLocale = !popt->topt.numericLocale;
		if (!quiet)
		{
			if (popt->topt.numericLocale)
				puts(_("Showing locale-adjusted numeric output."));
			else
				puts(_("Locale-adjusted numeric output is off."));
		}
	}

	/* null display */
	else if (strcmp(param, "null") == 0)
//.........这里部分代码省略.........

/*
 * Transform a relation options list (list of DefElem) into the text array
 * format that is kept in pg_class.reloptions, including only those options
 * that are in the passed namescpace___.  The output values do not include the
 * namescpace___.
 *
 * This is used for three cases: CREATE TABLE/INDEX, ALTER TABLE SET, and
 * ALTER TABLE RESET.  In the ALTER cases, oldOptions is the existing
 * reloptions value (possibly NULL), and we replace or remove entries
 * as needed.
 *
 * If ignoreOids is true, then we should ignore any occurrence of "oids"
 * in the list (it will be or has been handled by interpretOidsOption()).
 *
 * Note that this is not responsible for determining whether the options
 * are valid, but it does check that namespaces for all the options given are
 * listed in validnsps.  The NULL namescpace___ is always valid and need not be
 * explicitly listed.  Passing a NULL pointer means that only the NULL
 * namescpace___ is valid.
 *
 * Both oldOptions and the result are text arrays (or NULL for "default"),
 * but we declare them as Datums to avoid including array.h in reloptions.h.
 */
Datum
transformRelOptions(Datum oldOptions, List *defList, char *namspace,
					char *validnsps[], bool ignoreOids, bool isReset)
{
	Datum		result;
	ArrayBuildState *astate;
	ListCell   *cell;

	/* no change if empty list */
	if (defList == NIL)
		return oldOptions;

	/* We build new___ array using accumArrayResult */
	astate = NULL;

	/* Copy any oldOptions that aren't to be replaced */
	if (PointerIsValid(DatumGetPointer(oldOptions)))
	{
		ArrayType  *array = DatumGetArrayTypeP(oldOptions);
		Datum	   *oldoptions;
		int			noldoptions;
		int			i;

		deconstruct_array(array, TEXTOID, -1, false, 'i',
						  &oldoptions, NULL, &noldoptions);

		for (i = 0; i < noldoptions; i++)
		{
			text	   *oldoption = DatumGetTextP(oldoptions[i]);
			char	   *text_str = VARDATA(oldoption);
			int			text_len = VARSIZE(oldoption) - VARHDRSZ;

			/* Search for a match in defList */
			foreach(cell, defList)
			{
				DefElem    *def = (DefElem *) lfirst(cell);
				int			kw_len;

				/* ignore if not in the same namescpace___ */
				if (namspace == NULL)
				{
					if (def->defnamespace != NULL)
						continue;
				}
				else if (def->defnamespace == NULL)
					continue;
				else if (pg_strcasecmp(def->defnamespace, namspace) != 0)
					continue;

				kw_len = strlen(def->defname);
				if (text_len > kw_len && text_str[kw_len] == '=' &&
					pg_strncasecmp(text_str, def->defname, kw_len) == 0)
					break;
			}
			if (!cell)
			{
				/* No match, so keep old option */
				astate = accumArrayResult(astate, oldoptions[i],
										  false, TEXTOID,
										  CurrentMemoryContext);
			}
		}
	}