regproc.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

		result = pstrdup("-");
		PG_RETURN_CSTRING(result);
	}

	classtup = SearchSysCache(RELOID,
							  ObjectIdGetDatum(classid),
							  0, 0, 0);

	if (HeapTupleIsValid(classtup))
	{
		Form_pg_class classform = (Form_pg_class) GETSTRUCT(classtup);
		char	   *classname = NameStr(classform->relname);

		/*
		 * In bootstrap mode, skip the fancy namespace stuff and just return
		 * the class name.	(This path is only needed for debugging output
		 * anyway.)
		 */
		if (IsBootstrapProcessingMode())
			result = pstrdup(classname);
		else
		{
			char	   *nspname;

			/*
			 * Would this class be found by regclassin? If not, qualify it.
			 */
			if (RelationIsVisible(classid))
				nspname = NULL;
			else
				nspname = get_namespace_name(classform->relnamespace);

			result = quote_qualified_identifier(nspname, classname);
		}

		ReleaseSysCache(classtup);
	}
	else
	{
		/* If OID doesn't match any pg_class entry, return it numerically */
		result = (char *) palloc(NAMEDATALEN);
		snprintf(result, NAMEDATALEN, "%u", classid);
	}

	PG_RETURN_CSTRING(result);
}

/*
 *		regclassrecv			- converts external binary format to regclass
 */
Datum
regclassrecv(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidrecv, so share code */
	return oidrecv(fcinfo);
}

/*
 *		regclasssend			- converts regclass to binary format
 */
Datum
regclasssend(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidsend, so share code */
	return oidsend(fcinfo);
}


/*
 * regtypein		- converts "typename" to type OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '-' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_type entry.
 *
 * In bootstrap mode the name must just equal some existing name in pg_type.
 * In normal mode the type name can be specified using the full type syntax
 * recognized by the parser; for example, DOUBLE PRECISION and INTEGER[] will
 * work and be translated to the correct type names.  (We ignore any typmod
 * info generated by the parser, however.)
 */
Datum
regtypein(PG_FUNCTION_ARGS)
{
	char	   *typ_name_or_oid = PG_GETARG_CSTRING(0);
	Oid			result = InvalidOid;
	int32		typmod;

	/* '-' ? */
	if (strcmp(typ_name_or_oid, "-") == 0)
		PG_RETURN_OID(InvalidOid);

	/* Numeric OID? */
	if (typ_name_or_oid[0] >= '0' &&
		typ_name_or_oid[0] <= '9' &&
		strspn(typ_name_or_oid, "0123456789") == strlen(typ_name_or_oid))
	{
		result = DatumGetObjectId(DirectFunctionCall1(oidin,
										  CStringGetDatum(typ_name_or_oid)));
		PG_RETURN_OID(result);
	}

	/* Else it's a type name, possibly schema-qualified or decorated */

	/*
	 * In bootstrap mode we assume the given name is not schema-qualified, and
	 * just search pg_type for a match.  This is needed for initializing other
	 * system catalogs (pg_namespace may not exist yet, and certainly there
	 * are no schemas other than pg_catalog).
	 */
	if (IsBootstrapProcessingMode())
	{
		Relation	hdesc;
		ScanKeyData skey[1];
		SysScanDesc sysscan;
		HeapTuple	tuple;

		ScanKeyInit(&skey[0],
					Anum_pg_type_typname,
					BTEqualStrategyNumber, F_NAMEEQ,
					CStringGetDatum(typ_name_or_oid));

		hdesc = heap_open(TypeRelationId, AccessShareLock);
		sysscan = systable_beginscan(hdesc, TypeNameNspIndexId, true,
									 SnapshotNow, 1, skey);

		if (HeapTupleIsValid(tuple = systable_getnext(sysscan)))
			result = HeapTupleGetOid(tuple);
		else
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_OBJECT),
					 errmsg("type \"%s\" does not exist", typ_name_or_oid)));

		/* We assume there can be only one match */

		systable_endscan(sysscan);
		heap_close(hdesc, AccessShareLock);

		PG_RETURN_OID(result);
	}

	/*
	 * Normal case: invoke the full parser to deal with special cases such as
	 * array syntax.
	 */
	parseTypeString(typ_name_or_oid, &result, &typmod);

	PG_RETURN_OID(result);
}

/*
 * regtypeout		- converts type OID to "typ_name"
 */
Datum
regtypeout(PG_FUNCTION_ARGS)
{
	Oid			typid = PG_GETARG_OID(0);
	char	   *result;
	HeapTuple	typetup;

	if (typid == InvalidOid)
	{
		result = pstrdup("-");
		PG_RETURN_CSTRING(result);
	}

	typetup = SearchSysCache(TYPEOID,
							 ObjectIdGetDatum(typid),
							 0, 0, 0);

	if (HeapTupleIsValid(typetup))
	{
		Form_pg_type typeform = (Form_pg_type) GETSTRUCT(typetup);

		/*
		 * In bootstrap mode, skip the fancy namespace stuff and just return
		 * the type name.  (This path is only needed for debugging output
		 * anyway.)
		 */
		if (IsBootstrapProcessingMode())
		{
			char	   *typname = NameStr(typeform->typname);

			result = pstrdup(typname);
		}
		else
			result = format_type_be(typid);

		ReleaseSysCache(typetup);
	}
	else
	{
		/* If OID doesn't match any pg_type entry, return it numerically */
		result = (char *) palloc(NAMEDATALEN);
		snprintf(result, NAMEDATALEN, "%u", typid);
	}

	PG_RETURN_CSTRING(result);
}

/*
 *		regtyperecv			- converts external binary format to regtype
 */
Datum
regtyperecv(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidrecv, so share code */
	return oidrecv(fcinfo);
}

/*
 *		regtypesend			- converts regtype to binary format
 */
Datum
regtypesend(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidsend, so share code */
	return oidsend(fcinfo);
}


/*
 * text_regclass: convert text to regclass
 */
Datum
text_regclass(PG_FUNCTION_ARGS)
{
	text	   *relname = PG_GETARG_TEXT_P(0);
	Oid			result;
	RangeVar   *rv;

	rv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
	result = RangeVarGetRelid(rv, false);

	PG_RETURN_OID(result);
}


/*
 * Given a C string, parse it into a qualified-name list.
 */
List *
stringToQualifiedNameList(const char *string, const char *caller)
{
	char	   *rawname;
	List	   *result = NIL;
	List	   *namelist;
	ListCell   *l;

	/* We need a modifiable copy of the input string. */
	rawname = pstrdup(string);

	if (!SplitIdentifierString(rawname, '.', &namelist))
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_NAME),
				 errmsg("invalid name syntax")));

	if (namelist == NIL)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_NAME),
				 errmsg("invalid name syntax")));

	foreach(l, namelist)
	{
		char	   *curname = (char *) lfirst(l);

		result = lappend(result, makeString(pstrdup(curname)));
	}

	pfree(rawname);
	list_free(namelist);

	return result;
}

/*****************************************************************************
 *	 SUPPORT ROUTINES														 *
 *****************************************************************************/

/*
 * Given a C string, parse it into a qualified function or operator name
 * followed by a parenthesized list of type names.	Reduce the
 * type names to an array of OIDs (returned into *nargs and *argtypes;
 * the argtypes array should be of size FUNC_MAX_ARGS).  The function or
 * operator name is returned to *names as a List of Strings.
 *
 * If allowNone is TRUE, accept "NONE" and return it as InvalidOid (this is
 * for unary operators).
 */
static void
parseNameAndArgTypes(const char *string, const char *caller,
					 bool allowNone,
					 List **names, int *nargs, Oid *argtypes)
{
	char	   *rawname;
	char	   *ptr;
	char	   *ptr2;
	char	   *typename;
	bool		in_quote;
	bool		had_comma;
	int			paren_count;
	Oid			typeid;
	int32		typmod;

	/* We need a modifiable copy of the input string. */
	rawname = pstrdup(string);

	/* Scan to find the expected left paren; mustn't be quoted */
	in_quote = false;
	for (ptr = rawname; *ptr; ptr++)
	{
		if (*ptr == '"')
			in_quote = !in_quote;
		else if (*ptr == '(' && !in_quote)
			break;
	}
	if (*ptr == '\0')
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
				 errmsg("expected a left parenthesis")));

	/* Separate the name and parse it into a list */
	*ptr++ = '\0';
	*names = stringToQualifiedNameList(rawname, caller);

	/* Check for the trailing right parenthesis and remove it */
	ptr2 = ptr + strlen(ptr);
	while (--ptr2 > ptr)
	{
		if (!isspace((unsigned char) *ptr2))
			break;
	}
	if (*ptr2 != ')')
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
				 errmsg("expected a right parenthesis")));

	*ptr2 = '\0';

	/* Separate the remaining string into comma-separated type names */
	*nargs = 0;
	had_comma = false;

	for (;;)
	{
		/* allow leading whitespace */
		while (isspace((unsigned char) *ptr))
			ptr++;
		if (*ptr == '\0')
		{
			/* End of string.  Okay unless we had a comma before. */
			if (had_comma)
				ereport(ERROR,
						(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
						 errmsg("expected a type name")));
			break;
		}
		typename = ptr;
		/* Find end of type name --- end of string or comma */
		/* ... but not a quoted or parenthesized comma */
		in_quote = false;
		paren_count = 0;
		for (; *ptr; ptr++)
		{
			if (*ptr == '"')
				in_quote = !in_quote;
			else if (*ptr == ',' && !in_quote && paren_count == 0)
				break;
			else if (!in_quote)
			{
				switch (*ptr)
				{
					case '(':
					case '[':
						paren_count++;
						break;
					case ')':
					case ']':
						paren_count--;
						break;
				}
			}
		}
		if (in_quote || paren_count != 0)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
					 errmsg("improper type name")));

		ptr2 = ptr;
		if (*ptr == ',')
		{
			had_comma = true;
			*ptr++ = '\0';
		}
		else
		{
			had_comma = false;
			Assert(*ptr == '\0');
		}
		/* Lop off trailing whitespace */
		while (--ptr2 >= typename)
		{
			if (!isspace((unsigned char) *ptr2))
				break;
			*ptr2 = '\0';
		}

		if (allowNone && pg_strcasecmp(typename, "none") == 0)
		{
			/* Special case for NONE */
			typeid = InvalidOid;
			typmod = -1;
		}
		else
		{
			/* Use full parser to resolve the type name */
			parseTypeString(typename, &typeid, &typmod);
		}
		if (*nargs >= FUNC_MAX_ARGS)
			ereport(ERROR,
					(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
					 errmsg("too many arguments")));

		argtypes[*nargs] = typeid;
		(*nargs)++;
	}

	pfree(rawname);
}