##########################################	The Implement of XmlHandle.##	@author Kai Yao(yaokai)#########################################  implement XmlHandle; include "sys.m";include "../dfs/dfsutil.m";include "xml.m";include "bufio.m";include "xmlhandle.m"; sys : Sys;xml : Xml;dfsutil : DFSUtil; DFSFile : import dfsutil;DFSNode : import dfsutil;DFSChunk : import dfsutil;Parser : import xml;Item : import xml; file2xml(xmlf : ref Sys->FD, file : ref DFSUtil->DFSFile) {	if (sys == nil)		sys = load Sys Sys->PATH;	sys->fprint(xmlf, "<file>");	sys->fprint(xmlf, "<name>%s</name>", file.name);	sys->fprint(xmlf, "<id>%d</id>", file.id);	sys->fprint(xmlf, "<rep>%d</rep>", file.replicas);	for (p := file.chunks; p != nil; p = tl p)		chunk2xml(xmlf, hd p);	sys->fprint(xmlf, "</file>");} chunk2xml(xmlf : ref Sys->FD, chunk : ref DFSUtil->DFSChunk){	if (sys == nil)		sys = load Sys Sys->PATH;	sys->fprint(xmlf, "<chunk>");	sys->fprint(xmlf, "<id>%d</id>", chunk.id);	sys->fprint(xmlf, "<offset>%bd</offset>", chunk.offset);	sys->fprint(xmlf, "<size>%d</size>", chunk.size);	for (p := chunk.nodes; p != nil; p = tl p)		node2xml(xmlf, hd p);	sys->fprint(xmlf, "</chunk>");}	node2xml(xmlf : ref Sys->FD, node : ref DFSUtil->DFSNode){	if (sys == nil)		sys = load Sys Sys->PATH;	sys->fprint(xmlf, "<node>");	sys->fprint(xmlf, "<a>%s</a>", node.addr);	sys->fprint(xmlf, "<p>%d</p>", node.port);	sys->fprint(xmlf, "<c>%d</c>", node.chunkNumber);	sys->fprint(xmlf, "</node>");} init(fileName : string) : ref Parser{	if (sys == nil)		sys = load Sys Sys->PATH;	xml = load Xml Xml->PATH;	dfsutil = load DFSUtil DFSUtil->PATH; 	xml->init();	dfsutil->init();	warning := chan of (Xml->Locator, string);	preelem : string;	(parser, err) := xml->open(fileName, warning, preelem);	if (parser == nil)		sys->print("Error: %s", err);	parser.next();	parser.down();	return parser;} xml2file(parser : ref Parser) : ref DFSFile{	(nil, name) := read(parser);	(nil, id) := read(parser);	(nil, rep) := read(parser);	file := ref DFSFile(int id, name, nil, int rep);	item := parser.next();	while(item != nil) {		parser.down();		chunk := xml2chunk(parser, int id);		file.addChunk(chunk);		item = parser.next();	}	parser.up();	return file;} xml2chunk(parser : ref Parser, fileId : int) : ref DFSChunk{	(nil, id) := read(parser);	(nil, offset) := read(parser);	(nil, size) := read(parser);	chunk := ref DFSChunk(int id, fileId, big offset, int size, nil); 	item := parser.next();	while (item != nil) {		parser.down();		node := xml2node(parser);		chunk.addNode(node);		item = parser.next();	}	parser.up();	return chunk;}	 xml2node(parser : ref Parser) : ref DFSNode{	(nil, addr) := read(parser);	(nil, port) := read(parser);	(nil, chunkNumber) := read(parser);	node := ref DFSNode(addr, int port, int chunkNumber);	parser.up();	return node;} read(parser : ref Parser) : (string, string){	name, text : string;	item := parser.next();	if (item == nil) 		return (nil, nil);	pick it := item {		Tag => name = it.name;		* => {			sys->print("Parsing error, wrong depth!\n");			return (nil, nil);		}	}	parser.down();	mark := parser.mark();	item = parser.next();	if (item == nil) {		return (name, nil);	}	pick it2 := item {		Tag => {			text = it2.name;			parser.goto(mark);			}		Text => {			text = it2.ch;			parser.up();		}		* => {			sys->print("Parsing error, wrong item!\n");			return (nil, nil);		}	}	return (name, text);}