mirror of
https://github.com/Jermolene/TiddlyWiki5
synced 2024-08-25 11:06:45 +00:00
480 lines
14 KiB
JavaScript
480 lines
14 KiB
JavaScript
/*\
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title: $:/core/modules/syncer.js
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type: application/javascript
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module-type: global
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The syncer transfers content to and from data sources using syncadaptor modules.
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\*/
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(function(){
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/*jslint node: true, browser: true */
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/*global $tw: false */
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"use strict";
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/*
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Instantiate the syncer with the following options:
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wiki: wiki to be synced
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*/
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function Syncer(options) {
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var self = this;
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this.wiki = options.wiki;
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// Find a working syncadaptor
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this.syncadaptor = undefined;
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$tw.modules.forEachModuleOfType("syncadaptor",function(title,module) {
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if(!self.syncadaptor && module.adaptorClass) {
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self.syncadaptor = new module.adaptorClass(self);
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}
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});
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// Only do anything if we've got a syncadaptor
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if(this.syncadaptor) {
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this.init();
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}
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}
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/*
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Error handling
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*/
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Syncer.prototype.showError = function(error) {
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alert("Syncer error: " + error);
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$tw.utils.log("Syncer error: " + error);
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};
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/*
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Message logging
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*/
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Syncer.prototype.log = function(/* arguments */) {
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var args = Array.prototype.slice.call(arguments,0);
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args[0] = "Syncer: " + args[0];
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// Temporarily disable logging to help the wood vs. trees situation; we need better filtering of log messages
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//$tw.utils.log.apply(null,args);
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};
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/*
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Constants
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*/
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Syncer.prototype.titleIsLoggedIn = "$:/status/IsLoggedIn";
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Syncer.prototype.titleUserName = "$:/status/UserName";
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Syncer.prototype.taskTimerInterval = 1 * 1000; // Interval for sync timer
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Syncer.prototype.throttleInterval = 1 * 1000; // Defer saving tiddlers if they've changed in the last 1s...
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Syncer.prototype.fallbackInterval = 10 * 1000; // Unless the task is older than 10s
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Syncer.prototype.pollTimerInterval = 60 * 1000; // Interval for polling for changes from the adaptor
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/*
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Initialise the syncer
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*/
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Syncer.prototype.init = function() {
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var self = this;
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// Hashmap by title of {revision:,changeCount:,adaptorInfo:}
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this.tiddlerInfo = {};
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// Record information for known tiddlers
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this.wiki.forEachTiddler(function(title,tiddler) {
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if(tiddler.fields["revision"]) {
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self.tiddlerInfo[title] = {
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revision: tiddler.fields["revision"],
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adaptorInfo: self.syncadaptor.getTiddlerInfo(tiddler),
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changeCount: self.wiki.getChangeCount(title)
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}
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}
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});
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// Tasks are {type: "load"/"save"/"delete", title:, queueTime:, lastModificationTime:}
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this.taskQueue = {}; // Hashmap of tasks to be performed
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this.taskInProgress = {}; // Hash of tasks in progress
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this.taskTimerId = null; // Timer for task dispatch
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this.pollTimerId = null; // Timer for polling server
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// Listen out for changes to tiddlers
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this.wiki.addEventListener("change",function(changes) {
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self.syncToServer(changes);
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});
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// Listen out for lazyLoad events
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this.wiki.addEventListener("lazyLoad",function(title) {
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self.handleLazyLoadEvent(title);
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});
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// Listen out for login/logout/refresh events in the browser
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if($tw.browser) {
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document.addEventListener("tw-login",function(event) {
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self.handleLoginEvent(event);
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},false);
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document.addEventListener("tw-logout",function(event) {
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self.handleLogoutEvent(event);
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},false);
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document.addEventListener("tw-server-refresh",function(event) {
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self.handleRefreshEvent(event);
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},false);
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}
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// Get the login status
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this.getStatus(function (err,isLoggedIn) {
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if(isLoggedIn) {
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// Do a sync from the server
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self.syncFromServer();
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}
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});
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};
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/*
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Save an incoming tiddler in the store, and updates the associated tiddlerInfo
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*/
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Syncer.prototype.storeTiddler = function(tiddlerFields) {
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// Save the tiddler
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var tiddler = new $tw.Tiddler(this.wiki.getTiddler(tiddlerFields.title),tiddlerFields);
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this.wiki.addTiddler(tiddler);
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// Save the tiddler revision and changeCount details
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this.tiddlerInfo[tiddlerFields.title] = {
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revision: tiddlerFields.revision,
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adaptorInfo: this.syncadaptor.getTiddlerInfo(tiddler),
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changeCount: this.wiki.getChangeCount(tiddlerFields.title)
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};
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};
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Syncer.prototype.getStatus = function(callback) {
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var self = this;
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// Check if the adaptor supports getStatus()
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if(this.syncadaptor.getStatus) {
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// Mark us as not logged in
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this.wiki.addTiddler({title: this.titleIsLoggedIn,text: "no"});
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// Get login status
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this.syncadaptor.getStatus(function(err,isLoggedIn,username) {
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if(err) {
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self.showError(err);
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return;
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}
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// Set the various status tiddlers
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self.wiki.addTiddler({title: self.titleIsLoggedIn,text: isLoggedIn ? "yes" : "no"});
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if(isLoggedIn) {
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self.wiki.addTiddler({title: self.titleUserName,text: username});
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} else {
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self.wiki.deleteTiddler(self.titleUserName);
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}
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// Invoke the callback
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if(callback) {
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callback(err,isLoggedIn,username);
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}
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});
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} else {
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callback(null,true,"UNAUTHENTICATED");
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}
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};
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/*
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Synchronise from the server by reading the skinny tiddler list and queuing up loads for any tiddlers that we don't already have up to date
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*/
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Syncer.prototype.syncFromServer = function() {
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if(this.syncadaptor.getSkinnyTiddlers) {
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this.log("Retrieving skinny tiddler list");
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var self = this;
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if(this.pollTimerId) {
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clearTimeout(this.pollTimerId);
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this.pollTimerId = null;
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}
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this.syncadaptor.getSkinnyTiddlers(function(err,tiddlers) {
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// Trigger another sync
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self.pollTimerId = setTimeout(function() {
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self.pollTimerId = null;
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self.syncFromServer.call(self);
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},self.pollTimerInterval);
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// Check for errors
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if(err) {
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self.log("Error retrieving skinny tiddler list:",err);
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return;
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}
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// Process each incoming tiddler
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for(var t=0; t<tiddlers.length; t++) {
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// Get the incoming tiddler fields, and the existing tiddler
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var tiddlerFields = tiddlers[t],
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incomingRevision = tiddlerFields.revision,
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tiddler = self.wiki.getTiddler(tiddlerFields.title),
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tiddlerInfo = self.tiddlerInfo[tiddlerFields.title],
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currRevision = tiddlerInfo ? tiddlerInfo.revision : null;
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// Ignore the incoming tiddler if it's the same as the revision we've already got
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if(currRevision !== incomingRevision) {
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// Do a full load if we've already got a fat version of the tiddler
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if(tiddler && tiddler.fields.text !== undefined) {
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// Do a full load of this tiddler
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self.enqueueSyncTask({
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type: "load",
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title: tiddlerFields.title
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});
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} else {
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// Load the skinny version of the tiddler
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self.storeTiddler(tiddlerFields);
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}
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}
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}
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});
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}
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};
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/*
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Synchronise a set of changes to the server
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*/
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Syncer.prototype.syncToServer = function(changes) {
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var self = this,
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now = new Date();
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$tw.utils.each(changes,function(change,title,object) {
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// Ignore the change if it is a shadow tiddler
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if((change.deleted && $tw.utils.hop(self.tiddlerInfo,title)) || (!change.deleted && self.wiki.tiddlerExists(title))) {
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// Queue a task to sync this tiddler
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self.enqueueSyncTask({
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type: change.deleted ? "delete" : "save",
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title: title
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});
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}
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});
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};
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/*
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Lazily load a skinny tiddler if we can
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*/
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Syncer.prototype.handleLazyLoadEvent = function(title) {
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// Queue up a sync task to load this tiddler
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this.enqueueSyncTask({
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type: "load",
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title: title
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});
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};
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/*
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Dispay a password prompt and allow the user to login
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*/
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Syncer.prototype.handleLoginEvent = function() {
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var self = this;
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this.getStatus(function(err,isLoggedIn,username) {
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if(!isLoggedIn) {
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$tw.passwordPrompt.createPrompt({
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serviceName: "Login to TiddlySpace",
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callback: function(data) {
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self.login(data.username,data.password,function(err,isLoggedIn) {
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self.syncFromServer();
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});
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return true; // Get rid of the password prompt
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}
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});
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}
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});
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};
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/*
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Attempt to login to TiddlyWeb.
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username: username
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password: password
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callback: invoked with arguments (err,isLoggedIn)
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*/
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Syncer.prototype.login = function(username,password,callback) {
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this.log("Attempting to login as",username);
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var self = this;
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if(this.syncadaptor.login) {
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this.syncadaptor.login(username,password,function(err) {
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if(err) {
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return callback(err);
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}
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self.getStatus(function(err,isLoggedIn,username) {
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if(callback) {
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callback(null,isLoggedIn);
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}
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});
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});
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} else {
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callback(null,true);
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}
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};
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/*
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Attempt to log out of TiddlyWeb
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*/
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Syncer.prototype.handleLogoutEvent = function() {
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this.log("Attempting to logout");
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var self = this;
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if(this.syncadaptor.logout) {
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this.syncadaptor.logout(function(err) {
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if(err) {
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self.showError(err);
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} else {
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self.getStatus();
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}
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});
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}
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};
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/*
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Immediately refresh from the server
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*/
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Syncer.prototype.handleRefreshEvent = function() {
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this.syncFromServer();
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};
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/*
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Queue up a sync task. If there is already a pending task for the tiddler, just update the last modification time
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*/
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Syncer.prototype.enqueueSyncTask = function(task) {
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var self = this,
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now = new Date();
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// Set the timestamps on this task
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task.queueTime = now;
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task.lastModificationTime = now;
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// Fill in some tiddlerInfo if the tiddler is one we haven't seen before
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if(!$tw.utils.hop(this.tiddlerInfo,task.title)) {
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this.tiddlerInfo[task.title] = {
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revision: null,
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adaptorInfo: {},
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changeCount: -1
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}
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}
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// Bail if this is a save and the tiddler is already at the changeCount that the server has
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if(task.type === "save" && this.wiki.getChangeCount(task.title) <= this.tiddlerInfo[task.title].changeCount) {
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return;
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}
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// Check if this tiddler is already in the queue
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if($tw.utils.hop(this.taskQueue,task.title)) {
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this.log("Re-queueing up sync task with type:",task.type,"title:",task.title);
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var existingTask = this.taskQueue[task.title];
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// If so, just update the last modification time
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existingTask.lastModificationTime = task.lastModificationTime;
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// If the new task is a save then we upgrade the existing task to a save. Thus a pending load is turned into a save if the tiddler changes locally in the meantime. But a pending save is not modified to become a load
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if(task.type === "save" || task.type === "delete") {
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existingTask.type = task.type;
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}
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} else {
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this.log("Queuing up sync task with type:",task.type,"title:",task.title);
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// If it is not in the queue, insert it
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this.taskQueue[task.title] = task;
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}
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// Process the queue
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$tw.utils.nextTick(function() {self.processTaskQueue.call(self);});
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};
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/*
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Return the number of tasks in progress
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*/
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Syncer.prototype.numTasksInProgress = function() {
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return $tw.utils.count(this.taskInProgress);
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};
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/*
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Return the number of tasks in the queue
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*/
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Syncer.prototype.numTasksInQueue = function() {
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return $tw.utils.count(this.taskQueue);
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};
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/*
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Trigger a timeout if one isn't already outstanding
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*/
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Syncer.prototype.triggerTimeout = function() {
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var self = this;
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if(!this.taskTimerId) {
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this.taskTimerId = setTimeout(function() {
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self.taskTimerId = null;
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self.processTaskQueue.call(self);
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},self.taskTimerInterval);
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}
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};
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/*
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Process the task queue, performing the next task if appropriate
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*/
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Syncer.prototype.processTaskQueue = function() {
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var self = this;
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// Only process a task if we're not already performing a task. If we are already performing a task then we'll dispatch the next one when it completes
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if(this.numTasksInProgress() === 0) {
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// Choose the next task to perform
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var task = this.chooseNextTask();
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// Perform the task if we had one
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if(task) {
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// Remove the task from the queue and add it to the in progress list
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delete this.taskQueue[task.title];
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this.taskInProgress[task.title] = task;
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// Dispatch the task
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this.dispatchTask(task,function(err) {
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// Mark that this task is no longer in progress
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delete self.taskInProgress[task.title];
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// Process the next task
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self.processTaskQueue.call(self);
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});
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} else {
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// Make sure we've set a time if there wasn't a task to perform, but we've still got tasks in the queue
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if(this.numTasksInQueue() > 0) {
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this.triggerTimeout();
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}
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}
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}
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};
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/*
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Choose the next applicable task
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*/
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Syncer.prototype.chooseNextTask = function() {
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var self = this,
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candidateTask = null,
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now = new Date();
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// Select the best candidate task
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$tw.utils.each(this.taskQueue,function(task,title) {
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// Exclude the task if there's one of the same name in progress
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if($tw.utils.hop(self.taskInProgress,title)) {
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return;
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}
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// Exclude the task if it is a save and the tiddler has been modified recently, but not hit the fallback time
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if(task.type === "save" && (now - task.lastModificationTime) < self.throttleInterval &&
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(now - task.queueTime) < self.fallbackInterval) {
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return;
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}
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// Exclude the task if it is newer than the current best candidate
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if(candidateTask && candidateTask.queueTime < task.queueTime) {
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return;
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}
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// Now this is our best candidate
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candidateTask = task;
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});
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return candidateTask;
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};
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/*
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Dispatch a task and invoke the callback
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*/
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Syncer.prototype.dispatchTask = function(task,callback) {
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var self = this;
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if(task.type === "save") {
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var changeCount = this.wiki.getChangeCount(task.title),
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tiddler = this.wiki.getTiddler(task.title);
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this.log("Dispatching 'save' task:",task.title);
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this.syncadaptor.saveTiddler(tiddler,function(err,adaptorInfo,revision) {
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if(err) {
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return callback(err);
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}
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// Adjust the info stored about this tiddler
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self.tiddlerInfo[task.title] = {
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changeCount: changeCount,
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adaptorInfo: adaptorInfo,
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revision: revision
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};
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// Invoke the callback
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callback(null);
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});
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} else if(task.type === "load") {
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// Load the tiddler
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this.log("Dispatching 'load' task:",task.title);
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this.syncadaptor.loadTiddler(task.title,function(err,tiddlerFields) {
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if(err) {
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return callback(err);
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}
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// Store the tiddler
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self.storeTiddler(tiddlerFields);
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// Invoke the callback
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callback(null);
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});
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} else if(task.type === "delete") {
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// Delete the tiddler
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this.log("Dispatching 'delete' task:",task.title);
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this.syncadaptor.deleteTiddler(task.title,function(err) {
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if(err) {
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return callback(err);
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}
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// Invoke the callback
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callback(null);
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});
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}
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};
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exports.Syncer = Syncer;
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})();
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