#########################################	The implemention of DFSServer.#	DFSServer is the service interface that DFSMaster can provide to DFSClient.#	DFSServer announce a Connection,#	listen the message from other computing equipment,#	and call appropriate function in dfsmaster.#	#	@author Kai Yao(yaokai)#	@author Yang Fan(fyabc) #########################################  implement DFSServer; include "sys.m";include "draw.m";include "dfsmaster.m";include "dfsutil.m";include "hash.m";include "tables.m";include "../xml/xmlhandle.m"; include "xml.m";include "bufio.m"; Connection : import sys; DFSFile : import dfsutil;DFSChunk : import dfsutil;DFSNode : import dfsutil; sys : Sys;dfsmaster : DFSMaster;dfsutil : DFSUtil;xmlhandle : XmlHandle; dataPath : con "/appl/MR/hostser/";homePath : con "/appl/MR/"; mutex : chan of int;  DFSServer : module {	init : fn(ctxt : ref Draw->Context, args : list of string);}; init(ctxt : ref Draw->Context, args : list of string){	sys = load Sys Sys->PATH;	dfsutil = load DFSUtil DFSUtil->PATH;	dfsmaster = load DFSMaster DFSMaster->PATH;	xmlhandle = load XmlHandle XmlHandle->PATH;		dfsmaster->init();	dfsutil->init(); 	mutex = chan [1] of int; 	(n, conn) := sys->announce("tcp!*!2333");	if (n < 0) {		sys->print("DFSServer: announce failed %r\n");		exit;	}	while(1) {		listen(conn, ctxt);	}} listen(conn : Connection, ctxt : ref Draw->Context) {	buf := array [sys->ATOMICIO] of byte;	(ok, c) := sys->listen(conn);	if (ok < 0) {		sys->print("DFSServer: listen failed %r\n");	    exit;	}	rdf := sys->open(conn.dir + "/remote", sys->OREAD);	n := sys->read(rdf, buf, len buf);	connHandle(c, ctxt);} connHandle(conn : Connection, ctxt : ref Draw->Context){	addr := array [sys->ATOMICIO] of byte;	msgStr := array [sys->ATOMICIO] of byte;	msg : list of string;		rdfd := sys->open(conn.dir + "/data", sys->OREAD);	wdfd := sys->open(conn.dir + "/data", sys->OWRITE);	rfd := sys->open(conn.dir + "/remote", sys->OREAD); 	addrlen := sys->read(rfd, addr, len addr);	sys->print("Message from: %s\n", string addr[:addrlen]); 	msglen := sys->read(rdfd, msgStr, len msgStr);	receive : while (msglen > 0) {		(nil, msg) = sys->tokenize(string msgStr[:msglen], "@");		op := hd msg;		msg = tl msg;		case (op)		{			"disconnect" => break receive;			"create" => {				name := hd msg;				msg = tl msg;				replicas := int hd msg;				dfsmaster->createFile(name, replicas);				sys->fprint(wdfd, "Successfully create file %s !\n", name);			} 			"delete" => {				name := hd msg;				msg =tl msg;				ok := dfsmaster->deleteFile(name);				if (ok == 0)					sys->fprint(wdfd, "Successfully delete file %s !\n", name);				else					sys->fprint(wdfd, "No such file in file list!\n");			} 			"list" => {				fileList := dfsmaster->listFiles();				sys->fprint(wdfd, "%s", list2string(fileList));			}						"get" => {				name := hd msg;				msg = tl msg;				file := dfsmaster->getFile(name); 				if (file == nil) {					sys->fprint(wdfd, "No such file!\n");					break receive;				}				else 					sys->fprint(wdfd, "Successly find file %s\n", name); 				buf := array [100] of byte;				sys->read(rdfd, buf, len buf);				xmlf := sys->create(dataPath + name + ".xml", sys->ORDWR, 8r600);				xmlhandle->file2xml(xmlf, file);				sys->seek(xmlf, big 0, Sys->SEEKSTART);				sendXml(name, xmlf, conn);				break receive;			} 			"chunk" => {				name := hd msg;				msg = tl msg;				offset := big hd msg;				msg = tl msg;				size := int hd msg;				ok := dfsmaster->createChunk(name, offset, size);				sys->fprint(wdfd, "%d", ok);			} 			"upNode" => {				addr := hd msg;				msg = tl msg;				port := int hd msg;				msg = tl msg;				chunkNumber := int hd msg;				node := ref DFSNode(addr, port, chunkNumber);				dfsmaster->updateNode(node);				sys->fprint(wdfd, "Successfully update node %s", node.toString());			}						"rmNode" => {				addr := hd msg;				msg = tl msg;				port := int hd msg;			    msg = tl msg;				ok := dfsmaster->removeNode(ref DFSNode(addr, port, 0));				if (ok == 0)					sys->fprint(wdfd, "Successfully remove node addr: %s, port: %d\n", addr, port);				else					sys->fprint(wdfd, "No such node in node list!\n");								}			* =>				sys->fprint(wdfd, "Unknown message!\n");		}		msglen = sys->read(rdfd, msgStr, len msgStr);	} } list2string(src : list of string) : string{	ret : string;	for (p := src; p != nil; p = tl p)		ret = ret + hd p;	return ret;} sendXml(name : string, xmlf : ref Sys->FD, conn : Connection){	mutex <- = 0;	dfd := sys->open(conn.dir + "/data", sys->ORDWR);	sys->mount(dfd, nil, dataPath + "remote",Sys->MCREATE, nil);	xmlf2 := sys->create(dataPath + "remote/" + name + ".xml", sys->ORDWR, 8r600);	buf := array [Sys->ATOMICIO] of byte;	length : int;	do {		length = sys->read(xmlf, buf, len buf);		sys->write(xmlf2, buf[:length], length);	}while ( length == len buf);	sys->unmount(nil, dataPath + "remote");	sys->remove(dataPath + name + ".xml");	<- mutex;}