xml.c

postgresql8.3.4源码,开源数据库

		}

		pfree(elem_values);
		pfree(elem_nulls);
	}
	else
	{
		Oid			typeOut;
		bool		isvarlena;
		char	   *p,
				   *str;

		/*
		 * Special XSD formatting for some data types
		 */
		switch (type)
		{
			case BOOLOID:
				if (DatumGetBool(value))
					return "true";
				else
					return "false";

			case DATEOID:
				{
					DateADT		date;
					struct pg_tm tm;
					char		buf[MAXDATELEN + 1];

					date = DatumGetDateADT(value);
					j2date(date + POSTGRES_EPOCH_JDATE,
						   &(tm.tm_year), &(tm.tm_mon), &(tm.tm_mday));
					EncodeDateOnly(&tm, USE_XSD_DATES, buf);

					return pstrdup(buf);
				}

			case TIMESTAMPOID:
				{
					Timestamp	timestamp;
					struct pg_tm tm;
					fsec_t		fsec;
					char	   *tzn = NULL;
					char		buf[MAXDATELEN + 1];

					timestamp = DatumGetTimestamp(value);

					/* XSD doesn't support infinite values */
					if (TIMESTAMP_NOT_FINITE(timestamp))
						ereport(ERROR,
								(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
								 errmsg("timestamp out of range")));
					else if (timestamp2tm(timestamp, NULL, &tm, &fsec, NULL, NULL) == 0)
						EncodeDateTime(&tm, fsec, NULL, &tzn, USE_XSD_DATES, buf);
					else
						ereport(ERROR,
								(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
								 errmsg("timestamp out of range")));

					return pstrdup(buf);
				}

			case TIMESTAMPTZOID:
				{
					TimestampTz timestamp;
					struct pg_tm tm;
					int			tz;
					fsec_t		fsec;
					char	   *tzn = NULL;
					char		buf[MAXDATELEN + 1];

					timestamp = DatumGetTimestamp(value);

					/* XSD doesn't support infinite values */
					if (TIMESTAMP_NOT_FINITE(timestamp))
						ereport(ERROR,
								(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
								 errmsg("timestamp out of range")));
					else if (timestamp2tm(timestamp, &tz, &tm, &fsec, &tzn, NULL) == 0)
						EncodeDateTime(&tm, fsec, &tz, &tzn, USE_XSD_DATES, buf);
					else
						ereport(ERROR,
								(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
								 errmsg("timestamp out of range")));

					return pstrdup(buf);
				}
		}

		getTypeOutputInfo(type, &typeOut, &isvarlena);
		str = OidOutputFunctionCall(typeOut, value);

		if (type == XMLOID)
			return str;

#ifdef USE_LIBXML
		if (type == BYTEAOID)
		{
			xmlBufferPtr buf;
			xmlTextWriterPtr writer;
			char	   *result;

			xml_init();

			buf = xmlBufferCreate();
			writer = xmlNewTextWriterMemory(buf, 0);

			if (xmlbinary == XMLBINARY_BASE64)
				xmlTextWriterWriteBase64(writer, VARDATA(value), 0, VARSIZE(value) - VARHDRSZ);
			else
				xmlTextWriterWriteBinHex(writer, VARDATA(value), 0, VARSIZE(value) - VARHDRSZ);

			xmlFreeTextWriter(writer);
			result = pstrdup((const char *) xmlBufferContent(buf));
			xmlBufferFree(buf);
			return result;
		}
#endif   /* USE_LIBXML */

		for (p = str; *p; p += pg_mblen(p))
		{
			switch (*p)
			{
				case '&':
					appendStringInfo(&buf, "&");
					break;
				case '<':
					appendStringInfo(&buf, "&lt;");
					break;
				case '>':
					appendStringInfo(&buf, "&gt;");
					break;
				case '\r':
					appendStringInfo(&buf, "&#x0d;");
					break;
				default:
					appendBinaryStringInfo(&buf, p, pg_mblen(p));
					break;
			}
		}
	}

	return buf.data;
}


static char *
_SPI_strdup(const char *s)
{
	size_t		len = strlen(s) + 1;
	char	   *ret = SPI_palloc(len);

	memcpy(ret, s, len);
	return ret;
}


/*
 * SQL to XML mapping functions
 *
 * What follows below is intentionally organized so that you can read
 * along in the SQL/XML:2003 standard.	The functions are mostly split
 * up and ordered they way the clauses lay out in the standards
 * document, and the identifiers are also aligned with the standard
 * text.  (SQL/XML:2006 appears to be ordered differently,
 * unfortunately.)
 *
 * There are many things going on there:
 *
 * There are two kinds of mappings: Mapping SQL data (table contents)
 * to XML documents, and mapping SQL structure (the "schema") to XML
 * Schema.	And there are functions that do both at the same time.
 *
 * Then you can map a database, a schema, or a table, each in both
 * ways.  This breaks down recursively: Mapping a database invokes
 * mapping schemas, which invokes mapping tables, which invokes
 * mapping rows, which invokes mapping columns, although you can't
 * call the last two from the outside.	Because of this, there are a
 * number of xyz_internal() functions which are to be called both from
 * the function manager wrapper and from some upper layer in a
 * recursive call.
 *
 * See the documentation about what the common function arguments
 * nulls, tableforest, and targetns mean.
 *
 * Some style guidelines for XML output: Use double quotes for quoting
 * XML attributes.	Indent XML elements by two spaces, but remember
 * that a lot of code is called recursively at different levels, so
 * it's better not to indent rather than create output that indents
 * and outdents weirdly.  Add newlines to make the output look nice.
 */


/*
 * Visibility of objects for XML mappings; see SQL/XML:2003 section
 * 4.8.5.
 */

/*
 * Given a query, which must return type oid as first column, produce
 * a list of Oids with the query results.
 */
static List *
query_to_oid_list(const char *query)
{
	int			i;
	List	   *list = NIL;

	SPI_execute(query, true, 0);

	for (i = 0; i < SPI_processed; i++)
	{
		Datum		oid;
		bool		isnull;

		oid = SPI_getbinval(SPI_tuptable->vals[i],
							SPI_tuptable->tupdesc,
							1,
							&isnull);
		if (!isnull)
			list = lappend_oid(list, DatumGetObjectId(oid));
	}

	return list;
}


static List *
schema_get_xml_visible_tables(Oid nspid)
{
	StringInfoData query;

	initStringInfo(&query);
	appendStringInfo(&query, "SELECT oid FROM pg_catalog.pg_class WHERE relnamespace = %u AND relkind IN ('r', 'v') AND pg_catalog.has_table_privilege (oid, 'SELECT') ORDER BY relname;", nspid);

	return query_to_oid_list(query.data);
}


/*
 * Including the system schemas is probably not useful for a database
 * mapping.
 */
#define XML_VISIBLE_SCHEMAS_EXCLUDE "(nspname ~ '^pg_' OR nspname = 'information_schema')"

#define XML_VISIBLE_SCHEMAS "SELECT oid FROM pg_catalog.pg_namespace WHERE pg_catalog.has_schema_privilege (oid, 'USAGE') AND NOT " XML_VISIBLE_SCHEMAS_EXCLUDE


static List *
database_get_xml_visible_schemas(void)
{
	return query_to_oid_list(XML_VISIBLE_SCHEMAS " ORDER BY nspname;");
}


static List *
database_get_xml_visible_tables(void)
{
	/* At the moment there is no order required here. */
	return query_to_oid_list("SELECT oid FROM pg_catalog.pg_class WHERE relkind IN ('r', 'v') AND pg_catalog.has_table_privilege (pg_class.oid, 'SELECT') AND relnamespace IN (" XML_VISIBLE_SCHEMAS ");");
}


/*
 * Map SQL table to XML and/or XML Schema document; see SQL/XML:2003
 * section 9.3.
 */

static StringInfo
table_to_xml_internal(Oid relid,
					  const char *xmlschema, bool nulls, bool tableforest,
					  const char *targetns, bool top_level)
{
	StringInfoData query;

	initStringInfo(&query);
	appendStringInfo(&query, "SELECT * FROM %s",
					 DatumGetCString(DirectFunctionCall1(regclassout,
												  ObjectIdGetDatum(relid))));
	return query_to_xml_internal(query.data, get_rel_name(relid),
								 xmlschema, nulls, tableforest,
								 targetns, top_level);
}


Datum
table_to_xml(PG_FUNCTION_ARGS)
{
	Oid			relid = PG_GETARG_OID(0);
	bool		nulls = PG_GETARG_BOOL(1);
	bool		tableforest = PG_GETARG_BOOL(2);
	const char *targetns = _textout(PG_GETARG_TEXT_P(3));

	PG_RETURN_XML_P(stringinfo_to_xmltype(table_to_xml_internal(relid, NULL,
														  nulls, tableforest,
														   targetns, true)));
}


Datum
query_to_xml(PG_FUNCTION_ARGS)
{
	char	   *query = _textout(PG_GETARG_TEXT_P(0));
	bool		nulls = PG_GETARG_BOOL(1);
	bool		tableforest = PG_GETARG_BOOL(2);
	const char *targetns = _textout(PG_GETARG_TEXT_P(3));

	PG_RETURN_XML_P(stringinfo_to_xmltype(query_to_xml_internal(query, NULL,
													NULL, nulls, tableforest,
														   targetns, true)));
}


Datum
cursor_to_xml(PG_FUNCTION_ARGS)
{
	char	   *name = _textout(PG_GETARG_TEXT_P(0));
	int32		count = PG_GETARG_INT32(1);
	bool		nulls = PG_GETARG_BOOL(2);
	bool		tableforest = PG_GETARG_BOOL(3);
	const char *targetns = _textout(PG_GETARG_TEXT_P(4));

	StringInfoData result;
	Portal		portal;
	int			i;

	initStringInfo(&result);

	SPI_connect();
	portal = SPI_cursor_find(name);
	if (portal == NULL)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_CURSOR),
				 errmsg("cursor \"%s\" does not exist", name)));

	SPI_cursor_fetch(portal, true, count);
	for (i = 0; i < SPI_processed; i++)
		SPI_sql_row_to_xmlelement(i, &result, NULL, nulls,
								  tableforest, targetns, true);

	SPI_finish();

	PG_RETURN_XML_P(stringinfo_to_xmltype(&result));
}


/*
 * Write the start tag of the root element of a data mapping.
 *
 * top_level means that this is the very top level of the eventual
 * output.	For example, when the user calls table_to_xml, then a call
 * with a table name to this function is the top level.  When the user
 * calls database_to_xml, then a call with a schema name to this
 * function is not the top level.  If top_level is false, then the XML
 * namespace declarations are omitted, because they supposedly already
 * appeared earlier in the output.	Repeating them is not wrong, but
 * it looks ugly.
 */
static void
xmldata_root_element_start(StringInfo result, const char *eltname,
						   const char *xmlschema, const char *targetns,
						   bool top_level)
{
	/* This isn't really wrong but currently makes no sense. */
	Assert(top_level || !xmlschema);

	appendStringInfo(result, "<%s", eltname);
	if (top_level)
	{
		appendStringInfoString(result, " xmlns:xsi=\"" NAMESPACE_XSI "\"");
		if (strlen(targetns) > 0)
			appendStringInfo(result, " xmlns=\"%s\"", targetns);
	}
	if (xmlschema)
	{
		/* FIXME: better targets */
		if (strlen(targetns) > 0)
			appendStringInfo(result, " xsi:schemaLocation=\"%s #\"", targetns);
		else
			appendStringInfo(result, " xsi:noNamespaceSchemaLocation=\"#\"");
	}
	appendStringInfo(result, ">\n\n");
}


static void
xmldata_root_element_end(StringInfo result, const char *eltname)
{
	appendStringInfo(result, "</%s>\n", eltname);
}


static StringInfo
query_to_xml_internal(const char *query, char *tablename,
					  const char *xmlschema, bool nulls, bool tableforest,
					  const char *targetns, bool top_level)
{
	StringInfo	result;
	char	   *xmltn;
	int			i;

	if (tablename)
		xmltn = map_sql_identifier_to_xml_name(tablename, true, false);
	else
		xmltn = "table";

	result = makeStringInfo();

	SPI_connect();
	if (SPI_execute(query, true, 0) != SPI_OK_SELECT)
		ereport(ERROR,
				(errcode(ERRCODE_DATA_EXCEPTION),
				 errmsg("invalid query")));

	if (!tableforest)
		xmldata_root_element_start(result, xmltn, xmlschema,
								   targetns, top_level);

	if (xmlschema)
		appendStringInfo(result, "%s\n\n", xmlschema);

	for (i = 0; i < SPI_processed; i++)
		SPI_sql_row_to_xmlelement(i, result, tablename, nulls,
								  tableforest, targetns, top_level);

	if (!tableforest)
		xmldata_root_element_end(result, xmltn);

	SPI_finish();

	return result;
}


Datum
table_to_xmlschema(PG_FUNCTION_ARGS)
{
	Oid			relid = PG_GETARG_OID(0);
	bool		nulls = PG_GETARG_BOOL(1);
	bool		tableforest = PG_GETARG_BOOL(2);
	const char *targetns = _textout(PG_GETARG_TEXT_P(3));
	const char *result;
	Relation	rel;

	rel = heap_open(relid, AccessShareLock);
	result = map_sql_table_to_xmlschema(rel->rd_att, relid, nulls,
										tableforest, targetns);
	heap_close(rel, NoLock);

	PG_RETURN_XML_P(cstring_to_xmltype(result));
}


Datum
query_to_xmlschema(PG_FUNCTION_ARGS)
{
	char	   *query = _textout(PG_GETARG_TEXT_P(0));
	bool		nulls = PG_GETARG_BOOL(1);
	bool		tableforest = PG_GETARG_BOOL(2);
	const char *targetns = _textout(PG_GETARG_TEXT_P(3));
	const char *result;
	SPIPlanPtr	plan;
	Portal		portal;

	SPI_connect();

	if ((plan = SPI_prepare(query, 0, NULL)) == NULL)
		elog(ERROR, "SPI_prepare(\"%s\") failed", query);

	if ((portal = SPI_cursor_open(NULL, plan, NULL, NULL, true)) == NULL)
		elog(ERROR, "SPI_cursor_open(\"%s\") failed", query);

	result = _SPI_strdup(map_sql_table_to_xmlschema(portal->tupDesc,
													InvalidOid, nulls,
													tableforest, targetns));
	SPI_cursor_close(portal);
	SPI_finish();

	PG_RETURN_XML_P(cstring_to_xmltype(result));
}


Datum
cursor_to_xmlschema(PG_FUNCTION_ARGS)
{
	char	   *name = _textout(PG_GETARG_TEXT_P(0));
	bool		nulls = PG_GETARG_BOOL(1);
	bool		tableforest = PG_GETARG_BOOL(2);
	const char *targetns = _textout(PG_GETARG_TEXT_P(3));
	const char *xmlschema;
	Portal		portal;

	SPI_connect();
	portal = SPI_cursor_find(name);
	if (portal == NULL)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_CURSOR),
				 errmsg("cursor \"%s\" does not exist", name)));

	xmlschema = _SPI_strdup(map_sql_table_to_xmlschema(portal->tupDesc,
													   InvalidOid, nulls,
													 tableforest, targetns));
	SPI_finish();

	PG_RETURN_XML_P(cstring_to_xmltype(xmlschema));
}


Datum
table_to_xml_and_xmlschema(PG_FUNCTION_ARGS)
{
	Oid			relid = PG_GETARG_OID(0);
	bool		nulls = PG_GETARG_BOOL(1);
	bool		tableforest = PG_GETARG_BOOL(2);
	const char *targetns = _textout(PG_GETARG_TEXT_P(3));
	Relation	rel;
	const char *xmlschema;

	rel = heap_open(relid, AccessShareLock);
	xmlschema = map_sql_table_to_xmlschema(rel->rd_att, relid, nulls,
										   tableforest, targetns);
	heap_close(rel, NoLock);

	PG_RETURN_XML_P(stringinfo_to_xmltype(table_to_xml_internal(relid,
											   xmlschema, nulls, tableforest,
														   targetns, true)));
}


Datum
query_to_xml_and_xmlschema(PG_FUNCTION_ARGS)
{
	char	   *query = _textout(PG_GETARG_TEXT_P(0));
	bool		nulls = PG_GETARG_BOOL(1);
	bool		tableforest = PG_GETARG_BOOL(2);
	const char *targetns = _textout(PG_GETARG_TEXT_P(3));

	const char *xmlschema;
	SPIPlanPtr	plan;
	Portal		portal;

	SPI_connect();

	if ((plan = SPI_prepare(query, 0, NULL)) == NULL)
		elog(ERROR, "SPI_prepare(\"%s\") failed", query);

	if ((portal = SPI_cursor_open(NULL, plan, NULL, NULL, true)) == NULL)
		elog(ERROR, "SPI_cursor_open(\"%s\") failed", query);