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Diffstat (limited to 'tools/addon-sdk-1.5/packages/api-utils/lib/xhr.js')
-rw-r--r-- | tools/addon-sdk-1.5/packages/api-utils/lib/xhr.js | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/tools/addon-sdk-1.5/packages/api-utils/lib/xhr.js b/tools/addon-sdk-1.5/packages/api-utils/lib/xhr.js new file mode 100644 index 0000000..7c4fc29 --- /dev/null +++ b/tools/addon-sdk-1.5/packages/api-utils/lib/xhr.js @@ -0,0 +1,149 @@ +/* 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,Ci} = require("chrome"); + +// ## Implementation Notes ## +// +// Making `XMLHttpRequest` objects available to Jetpack code involves a +// few key principles universal to all low-level module implementations: +// +// * **Unloadability**. A Jetpack-based extension using this module can be +// asked to unload itself at any time, e.g. because the user decides to +// uninstall or disable the extension. This means we need to keep track of +// all in-progress reqests and abort them on unload. +// +// * **Developer-Ergonomic Tracebacks**. Whenever an exception is raised +// by a Jetpack-based extension, we want it to be logged in a +// place that is specific to that extension--so that a developer +// can distinguish it from an error on a web page or in another +// extension, for instance. We also want it to be logged with a +// full stack traceback, which the Mozilla platform doesn't usually +// do. +// +// Because of this, we don't actually want to give the Mozilla +// platform's "real" XHR implementation to clients, but instead provide +// a simple wrapper that trivially delegates to the implementation in +// all cases except where callbacks are involved: whenever Mozilla +// platform code calls into the extension, such as during the XHR's +// `onreadystatechange` callback, we want to wrap the client's callback +// in a try-catch clause that traps any exceptions raised by the +// callback and logs them via console.exception() instead of allowing +// them to propagate back into Mozilla platform code. + +// This is a private list of all active requests, so we know what to +// abort if we're asked to unload. +var requests = []; + +// Events on XHRs that we should listen for, so we know when to remove +// a request from our private list. +const TERMINATE_EVENTS = ["load", "error", "abort"]; + +// Read-only properties of XMLHttpRequest objects that we want to +// directly delegate to. +const READ_ONLY_PROPS = ["readyState", "responseText", "responseXML", + "status", "statusText"]; + +// Methods of XMLHttpRequest that we want to directly delegate to. +const DELEGATED_METHODS = ["abort", "getAllResponseHeaders", + "getResponseHeader", "overrideMimeType", + "send", "sendAsBinary", "setRequestHeader", + "open"]; + +var getRequestCount = exports.getRequestCount = function getRequestCount() { + return requests.length; +}; + +var XMLHttpRequest = exports.XMLHttpRequest = function XMLHttpRequest() { + var req = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"] + .createInstance(Ci.nsIXMLHttpRequest); + // For the sake of simplicity, don't tie this request to any UI. + req.mozBackgroundRequest = true; + + memory.track(req, "XMLHttpRequest"); + + this._req = req; + this._orsc = null; + + requests.push(this); + + var self = this; + + this._boundCleanup = function _boundCleanup() { + self._cleanup(); + }; + + TERMINATE_EVENTS.forEach( + function(name) { + self._req.addEventListener(name, self._boundCleanup, false); + }); +}; + +XMLHttpRequest.prototype = { + _cleanup: function _cleanup() { + this.onreadystatechange = null; + var index = requests.indexOf(this); + if (index != -1) { + var self = this; + TERMINATE_EVENTS.forEach( + function(name) { + self._req.removeEventListener(name, self._boundCleanup, false); + }); + requests.splice(index, 1); + } + }, + _unload: function _unload() { + this._req.abort(); + this._cleanup(); + }, + addEventListener: function addEventListener() { + throw new Error("not implemented"); + }, + removeEventListener: function removeEventListener() { + throw new Error("not implemented"); + }, + set upload(newValue) { + throw new Error("not implemented"); + }, + get onreadystatechange() { + return this._orsc; + }, + set onreadystatechange(cb) { + this._orsc = cb; + if (cb) { + var self = this; + this._req.onreadystatechange = function() { + try { + self._orsc.apply(self, arguments); + } catch (e) { + console.exception(e); + } + }; + } else + this._req.onreadystatechange = null; + } +}; + +READ_ONLY_PROPS.forEach( + function(name) { + XMLHttpRequest.prototype.__defineGetter__( + name, + function() { + return this._req[name]; + }); + }); + +DELEGATED_METHODS.forEach( + function(name) { + XMLHttpRequest.prototype[name] = function() { + return this._req[name].apply(this._req, arguments); + }; + }); + +require("./unload").when( + function() { + requests.slice().forEach(function(request) { request._unload(); }); + }); |