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mirror of https://github.com/Jermolene/TiddlyWiki5 synced 2024-12-25 17:40:29 +00:00
TiddlyWiki5/core/modules/syncer.js

510 lines
15 KiB
JavaScript

/*\
title: $:/core/modules/syncer.js
type: application/javascript
module-type: global
The syncer tracks changes to the store. If a syncadaptor is used then individual tiddlers are synchronised through it. If there is no syncadaptor then the entire wiki is saved via saver modules.
\*/
(function(){
/*jslint node: true, browser: true */
/*global $tw: false */
"use strict";
/*
Instantiate the syncer with the following options:
syncadaptor: reference to syncadaptor to be used
wiki: wiki to be synced
*/
function Syncer(options) {
var self = this;
this.wiki = options.wiki;
this.syncadaptor = options.syncadaptor;
// Make a logger
this.logger = new $tw.utils.Logger("syncer" + ($tw.browser ? "-browser" : "") + ($tw.node ? "-server" : ""));
// Compile the dirty tiddler filter
this.filterFn = this.wiki.compileFilter(this.wiki.getTiddlerText(this.titleSyncFilter));
// Record information for known tiddlers
this.readTiddlerInfo();
// Tasks are {type: "load"/"save"/"delete", title:, queueTime:, lastModificationTime:}
this.taskQueue = {}; // Hashmap of tasks yet to be performed
this.taskInProgress = {}; // Hash of tasks in progress
this.taskTimerId = null; // Timer for task dispatch
this.pollTimerId = null; // Timer for polling server
// Listen out for changes to tiddlers
this.wiki.addEventListener("change",function(changes) {
self.syncToServer(changes);
});
// Browser event handlers
if($tw.browser) {
// Set up our beforeunload handler
window.addEventListener("beforeunload",function(event) {
var confirmationMessage;
if(self.isDirty()) {
confirmationMessage = $tw.language.getString("UnsavedChangesWarning");
event.returnValue = confirmationMessage; // Gecko
}
return confirmationMessage;
});
// Listen out for login/logout/refresh events in the browser
$tw.rootWidget.addEventListener("tm-login",function() {
self.handleLoginEvent();
});
$tw.rootWidget.addEventListener("tm-logout",function() {
self.handleLogoutEvent();
});
$tw.rootWidget.addEventListener("tm-server-refresh",function() {
self.handleRefreshEvent();
});
}
// Listen out for lazyLoad events
this.wiki.addEventListener("lazyLoad",function(title) {
self.handleLazyLoadEvent(title);
});
// Get the login status
this.getStatus(function(err,isLoggedIn) {
// Do a sync from the server
self.syncFromServer();
});
}
/*
Constants
*/
Syncer.prototype.titleIsLoggedIn = "$:/status/IsLoggedIn";
Syncer.prototype.titleUserName = "$:/status/UserName";
Syncer.prototype.titleSyncFilter = "$:/config/SyncFilter";
Syncer.prototype.titleSavedNotification = "$:/language/Notifications/Save/Done";
Syncer.prototype.taskTimerInterval = 1 * 1000; // Interval for sync timer
Syncer.prototype.throttleInterval = 1 * 1000; // Defer saving tiddlers if they've changed in the last 1s...
Syncer.prototype.fallbackInterval = 10 * 1000; // Unless the task is older than 10s
Syncer.prototype.pollTimerInterval = 60 * 1000; // Interval for polling for changes from the adaptor
/*
Read (or re-read) the latest tiddler info from the store
*/
Syncer.prototype.readTiddlerInfo = function() {
// Hashmap by title of {revision:,changeCount:,adaptorInfo:}
this.tiddlerInfo = {};
// Record information for known tiddlers
var self = this,
tiddlers = this.filterFn.call(this.wiki);
$tw.utils.each(tiddlers,function(title) {
var tiddler = self.wiki.getTiddler(title);
self.tiddlerInfo[title] = {
revision: tiddler.fields.revision,
adaptorInfo: self.syncadaptor && self.syncadaptor.getTiddlerInfo(tiddler),
changeCount: self.wiki.getChangeCount(title)
};
});
};
/*
Checks whether the wiki is dirty (ie the window shouldn't be closed)
*/
Syncer.prototype.isDirty = function() {
return (this.numTasksInQueue() > 0) || (this.numTasksInProgress() > 0);
};
/*
Update the document body with the class "tc-dirty" if the wiki has unsaved/unsynced changes
*/
Syncer.prototype.updateDirtyStatus = function() {
if($tw.browser) {
$tw.utils.toggleClass(document.body,"tc-dirty",this.isDirty());
}
};
/*
Save an incoming tiddler in the store, and updates the associated tiddlerInfo
*/
Syncer.prototype.storeTiddler = function(tiddlerFields) {
// Save the tiddler
var tiddler = new $tw.Tiddler(this.wiki.getTiddler(tiddlerFields.title),tiddlerFields);
this.wiki.addTiddler(tiddler);
// Save the tiddler revision and changeCount details
this.tiddlerInfo[tiddlerFields.title] = {
revision: tiddlerFields.revision,
adaptorInfo: this.syncadaptor.getTiddlerInfo(tiddler),
changeCount: this.wiki.getChangeCount(tiddlerFields.title)
};
};
Syncer.prototype.getStatus = function(callback) {
var self = this;
// Check if the adaptor supports getStatus()
if(this.syncadaptor && this.syncadaptor.getStatus) {
// Mark us as not logged in
this.wiki.addTiddler({title: this.titleIsLoggedIn,text: "no"});
// Get login status
this.syncadaptor.getStatus(function(err,isLoggedIn,username) {
if(err) {
self.logger.alert(err);
return;
}
// Set the various status tiddlers
self.wiki.addTiddler({title: self.titleIsLoggedIn,text: isLoggedIn ? "yes" : "no"});
if(isLoggedIn) {
self.wiki.addTiddler({title: self.titleUserName,text: username || ""});
} else {
self.wiki.deleteTiddler(self.titleUserName);
}
// Invoke the callback
if(callback) {
callback(err,isLoggedIn,username);
}
});
} else {
callback(null,true,"UNAUTHENTICATED");
}
};
/*
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
*/
Syncer.prototype.syncFromServer = function() {
if(this.syncadaptor && this.syncadaptor.getSkinnyTiddlers) {
this.logger.log("Retrieving skinny tiddler list");
var self = this;
if(this.pollTimerId) {
clearTimeout(this.pollTimerId);
this.pollTimerId = null;
}
this.syncadaptor.getSkinnyTiddlers(function(err,tiddlers) {
// Trigger the next sync
self.pollTimerId = setTimeout(function() {
self.pollTimerId = null;
self.syncFromServer.call(self);
},self.pollTimerInterval);
// Check for errors
if(err) {
self.logger.alert("Error retrieving skinny tiddler list:",err);
return;
}
// Process each incoming tiddler
for(var t=0; t<tiddlers.length; t++) {
// Get the incoming tiddler fields, and the existing tiddler
var tiddlerFields = tiddlers[t],
incomingRevision = tiddlerFields.revision + "",
tiddler = self.wiki.getTiddler(tiddlerFields.title),
tiddlerInfo = self.tiddlerInfo[tiddlerFields.title],
currRevision = tiddlerInfo ? tiddlerInfo.revision : null;
// Ignore the incoming tiddler if it's the same as the revision we've already got
if(currRevision !== incomingRevision) {
// Do a full load if we've already got a fat version of the tiddler
if(tiddler && tiddler.fields.text !== undefined) {
// Do a full load of this tiddler
self.enqueueSyncTask({
type: "load",
title: tiddlerFields.title
});
} else {
// Load the skinny version of the tiddler
self.storeTiddler(tiddlerFields);
}
}
}
});
}
};
/*
Synchronise a set of changes to the server
*/
Syncer.prototype.syncToServer = function(changes) {
var self = this,
now = Date.now(),
filteredChanges = this.filterFn.call(this.wiki,function(callback) {
$tw.utils.each(changes,function(change,title) {
var tiddler = self.wiki.getTiddler(title);
callback(tiddler,title);
});
});
$tw.utils.each(changes,function(change,title,object) {
// Process the change if it is a deletion of a tiddler we're already syncing, or is on the filtered change list
if((change.deleted && $tw.utils.hop(self.tiddlerInfo,title)) || filteredChanges.indexOf(title) !== -1) {
// Queue a task to sync this tiddler
self.enqueueSyncTask({
type: change.deleted ? "delete" : "save",
title: title
});
}
});
};
/*
Lazily load a skinny tiddler if we can
*/
Syncer.prototype.handleLazyLoadEvent = function(title) {
// Queue up a sync task to load this tiddler
this.enqueueSyncTask({
type: "load",
title: title
});
};
/*
Dispay a password prompt and allow the user to login
*/
Syncer.prototype.handleLoginEvent = function() {
var self = this;
this.getStatus(function(err,isLoggedIn,username) {
if(!isLoggedIn) {
$tw.passwordPrompt.createPrompt({
serviceName: "Login to TiddlySpace",
callback: function(data) {
self.login(data.username,data.password,function(err,isLoggedIn) {
self.syncFromServer();
});
return true; // Get rid of the password prompt
}
});
}
});
};
/*
Attempt to login to TiddlyWeb.
username: username
password: password
callback: invoked with arguments (err,isLoggedIn)
*/
Syncer.prototype.login = function(username,password,callback) {
this.logger.log("Attempting to login as",username);
var self = this;
if(this.syncadaptor.login) {
this.syncadaptor.login(username,password,function(err) {
if(err) {
return callback(err);
}
self.getStatus(function(err,isLoggedIn,username) {
if(callback) {
callback(null,isLoggedIn);
}
});
});
} else {
callback(null,true);
}
};
/*
Attempt to log out of TiddlyWeb
*/
Syncer.prototype.handleLogoutEvent = function() {
this.logger.log("Attempting to logout");
var self = this;
if(this.syncadaptor.logout) {
this.syncadaptor.logout(function(err) {
if(err) {
self.logger.alert(err);
} else {
self.getStatus();
}
});
}
};
/*
Immediately refresh from the server
*/
Syncer.prototype.handleRefreshEvent = function() {
this.syncFromServer();
};
/*
Queue up a sync task. If there is already a pending task for the tiddler, just update the last modification time
*/
Syncer.prototype.enqueueSyncTask = function(task) {
var self = this,
now = Date.now();
// Set the timestamps on this task
task.queueTime = now;
task.lastModificationTime = now;
// Fill in some tiddlerInfo if the tiddler is one we haven't seen before
if(!$tw.utils.hop(this.tiddlerInfo,task.title)) {
this.tiddlerInfo[task.title] = {
revision: null,
adaptorInfo: {},
changeCount: -1
};
}
// Bail if this is a save and the tiddler is already at the changeCount that the server has
if(task.type === "save" && this.wiki.getChangeCount(task.title) <= this.tiddlerInfo[task.title].changeCount) {
return;
}
// Check if this tiddler is already in the queue
if($tw.utils.hop(this.taskQueue,task.title)) {
// this.logger.log("Re-queueing up sync task with type:",task.type,"title:",task.title);
var existingTask = this.taskQueue[task.title];
// If so, just update the last modification time
existingTask.lastModificationTime = task.lastModificationTime;
// 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
if(task.type === "save" || task.type === "delete") {
existingTask.type = task.type;
}
} else {
// this.logger.log("Queuing up sync task with type:",task.type,"title:",task.title);
// If it is not in the queue, insert it
this.taskQueue[task.title] = task;
this.updateDirtyStatus();
}
// Process the queue
$tw.utils.nextTick(function() {self.processTaskQueue.call(self);});
};
/*
Return the number of tasks in progress
*/
Syncer.prototype.numTasksInProgress = function() {
return $tw.utils.count(this.taskInProgress);
};
/*
Return the number of tasks in the queue
*/
Syncer.prototype.numTasksInQueue = function() {
return $tw.utils.count(this.taskQueue);
};
/*
Trigger a timeout if one isn't already outstanding
*/
Syncer.prototype.triggerTimeout = function() {
var self = this;
if(!this.taskTimerId) {
this.taskTimerId = setTimeout(function() {
self.taskTimerId = null;
self.processTaskQueue.call(self);
},self.taskTimerInterval);
}
};
/*
Process the task queue, performing the next task if appropriate
*/
Syncer.prototype.processTaskQueue = function() {
var self = this;
// 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
if(this.numTasksInProgress() === 0) {
// Choose the next task to perform
var task = this.chooseNextTask();
// Perform the task if we had one
if(task) {
// Remove the task from the queue and add it to the in progress list
delete this.taskQueue[task.title];
this.taskInProgress[task.title] = task;
this.updateDirtyStatus();
// Dispatch the task
this.dispatchTask(task,function(err) {
if(err) {
self.logger.alert("Sync error while processing '" + task.title + "':\n" + err);
}
// Mark that this task is no longer in progress
delete self.taskInProgress[task.title];
self.updateDirtyStatus();
// Process the next task
self.processTaskQueue.call(self);
});
} else {
// Make sure we've set a time if there wasn't a task to perform, but we've still got tasks in the queue
if(this.numTasksInQueue() > 0) {
this.triggerTimeout();
}
}
}
};
/*
Choose the next applicable task
*/
Syncer.prototype.chooseNextTask = function() {
var self = this,
candidateTask = null,
now = Date.now();
// Select the best candidate task
$tw.utils.each(this.taskQueue,function(task,title) {
// Exclude the task if there's one of the same name in progress
if($tw.utils.hop(self.taskInProgress,title)) {
return;
}
// Exclude the task if it is a save and the tiddler has been modified recently, but not hit the fallback time
if(task.type === "save" && (now - task.lastModificationTime) < self.throttleInterval &&
(now - task.queueTime) < self.fallbackInterval) {
return;
}
// Exclude the task if it is newer than the current best candidate
if(candidateTask && candidateTask.queueTime < task.queueTime) {
return;
}
// Now this is our best candidate
candidateTask = task;
});
return candidateTask;
};
/*
Dispatch a task and invoke the callback
*/
Syncer.prototype.dispatchTask = function(task,callback) {
var self = this;
if(task.type === "save") {
var changeCount = this.wiki.getChangeCount(task.title),
tiddler = this.wiki.getTiddler(task.title);
this.logger.log("Dispatching 'save' task:",task.title);
if(tiddler) {
this.syncadaptor.saveTiddler(tiddler,function(err,adaptorInfo,revision) {
if(err) {
return callback(err);
}
// Adjust the info stored about this tiddler
self.tiddlerInfo[task.title] = {
changeCount: changeCount,
adaptorInfo: adaptorInfo,
revision: revision
};
// Invoke the callback
callback(null);
},{
tiddlerInfo: self.tiddlerInfo[task.title]
});
} else {
this.logger.log(" Not Dispatching 'save' task:",task.title,"tiddler does not exist");
return callback(null);
}
} else if(task.type === "load") {
// Load the tiddler
this.logger.log("Dispatching 'load' task:",task.title);
this.syncadaptor.loadTiddler(task.title,function(err,tiddlerFields) {
if(err) {
return callback(err);
}
// Store the tiddler
if(tiddlerFields) {
self.storeTiddler(tiddlerFields);
}
// Invoke the callback
callback(null);
});
} else if(task.type === "delete") {
// Delete the tiddler
this.logger.log("Dispatching 'delete' task:",task.title);
this.syncadaptor.deleteTiddler(task.title,function(err) {
if(err) {
return callback(err);
}
delete self.tiddlerInfo[task.title];
// Invoke the callback
callback(null);
},{
tiddlerInfo: self.tiddlerInfo[task.title]
});
}
};
exports.Syncer = Syncer;
})();