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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict";
const Cc = Components.classes;
const Ci = Components.interfaces;
const Cu = Components.utils;
this.EXPORTED_SYMBOLS = ["DownloadsIPC"];
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/Services.jsm");
Cu.import("resource://gre/modules/Promise.jsm");
XPCOMUtils.defineLazyServiceGetter(this, "cpmm",
"@mozilla.org/childprocessmessagemanager;1",
"nsIMessageSender");
/**
* This module lives in the child process and receives the ipc messages
* from the parent. It saves the download's state and redispatch changes
* to DOM objects using an observer notification.
*
* This module needs to be loaded once and only once per process.
*/
function debug(aStr) {
#ifdef MOZ_DEBUG
dump("-*- DownloadsIPC.jsm : " + aStr + "\n");
#endif
}
const ipcMessages = ["Downloads:Added",
"Downloads:Removed",
"Downloads:Changed",
"Downloads:GetList:Return",
"Downloads:Remove:Return",
"Downloads:Pause:Return",
"Downloads:Resume:Return",
"Downloads:Adopt:Return"];
this.DownloadsIPC = {
downloads: {},
init: function() {
debug("init");
Services.obs.addObserver(this, "xpcom-shutdown", false);
ipcMessages.forEach((aMessage) => {
cpmm.addMessageListener(aMessage, this);
});
// We need to get the list of current downloads.
this.ready = false;
this.getListPromises = [];
this.downloadPromises = {};
cpmm.sendAsyncMessage("Downloads:GetList", {});
this._promiseId = 0;
},
notifyChanges: function(aId) {
// TODO: use the subject instead of stringifying.
if (this.downloads[aId]) {
debug("notifyChanges notifying changes for " + aId);
Services.obs.notifyObservers(null, "downloads-state-change-" + aId,
JSON.stringify(this.downloads[aId]));
} else {
debug("notifyChanges failed for " + aId)
}
},
_updateDownloadsArray: function(aDownloads) {
this.downloads = [];
// We actually have an array of downloads.
aDownloads.forEach((aDownload) => {
this.downloads[aDownload.id] = aDownload;
});
},
receiveMessage: function(aMessage) {
let download = aMessage.data;
debug("message: " + aMessage.name);
switch(aMessage.name) {
case "Downloads:GetList:Return":
this._updateDownloadsArray(download);
if (!this.ready) {
this.getListPromises.forEach(aPromise =>
aPromise.resolve(this.downloads));
this.getListPromises.length = 0;
}
this.ready = true;
break;
case "Downloads:Added":
this.downloads[download.id] = download;
this.notifyChanges(download.id);
break;
case "Downloads:Removed":
if (this.downloads[download.id]) {
this.downloads[download.id] = download;
this.notifyChanges(download.id);
delete this.downloads[download.id];
}
break;
case "Downloads:Changed":
// Only update properties that actually changed.
let cached = this.downloads[download.id];
if (!cached) {
debug("No download found for " + download.id);
return;
}
let props = ["totalBytes", "currentBytes", "url", "path", "state",
"contentType", "startTime"];
let changed = false;
props.forEach((aProp) => {
if (download[aProp] && (download[aProp] != cached[aProp])) {
cached[aProp] = download[aProp];
changed = true;
}
});
// Updating the error property. We always get a 'state' change as
// well.
cached.error = download.error;
if (changed) {
this.notifyChanges(download.id);
}
break;
case "Downloads:Remove:Return":
case "Downloads:Pause:Return":
case "Downloads:Resume:Return":
case "Downloads:Adopt:Return":
if (this.downloadPromises[download.promiseId]) {
if (!download.error) {
this.downloadPromises[download.promiseId].resolve(download);
} else {
this.downloadPromises[download.promiseId].reject(download);
}
delete this.downloadPromises[download.promiseId];
}
break;
}
},
/**
* Returns a promise that is resolved with the list of current downloads.
*/
getDownloads: function() {
debug("getDownloads()");
let deferred = Promise.defer();
if (this.ready) {
debug("Returning existing list.");
deferred.resolve(this.downloads);
} else {
this.getListPromises.push(deferred);
}
return deferred.promise;
},
/**
* Void function to trigger removal of completed downloads.
*/
clearAllDone: function() {
debug("clearAllDone");
cpmm.sendAsyncMessage("Downloads:ClearAllDone", {});
},
promiseId: function() {
return this._promiseId++;
},
remove: function(aId) {
debug("remove " + aId);
let deferred = Promise.defer();
let pId = this.promiseId();
this.downloadPromises[pId] = deferred;
cpmm.sendAsyncMessage("Downloads:Remove",
{ id: aId, promiseId: pId });
return deferred.promise;
},
pause: function(aId) {
debug("pause " + aId);
let deferred = Promise.defer();
let pId = this.promiseId();
this.downloadPromises[pId] = deferred;
cpmm.sendAsyncMessage("Downloads:Pause",
{ id: aId, promiseId: pId });
return deferred.promise;
},
resume: function(aId) {
debug("resume " + aId);
let deferred = Promise.defer();
let pId = this.promiseId();
this.downloadPromises[pId] = deferred;
cpmm.sendAsyncMessage("Downloads:Resume",
{ id: aId, promiseId: pId });
return deferred.promise;
},
adoptDownload: function(aJsonDownload) {
debug("adoptDownload");
let deferred = Promise.defer();
let pId = this.promiseId();
this.downloadPromises[pId] = deferred;
cpmm.sendAsyncMessage("Downloads:Adopt",
{ jsonDownload: aJsonDownload, promiseId: pId });
return deferred.promise;
},
observe: function(aSubject, aTopic, aData) {
if (aTopic == "xpcom-shutdown") {
ipcMessages.forEach((aMessage) => {
cpmm.removeMessageListener(aMessage, this);
});
}
}
};
DownloadsIPC.init();
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