gecko/dom/base/ConsoleAPIStorage.jsm
2012-05-21 12:12:37 +01:00

147 lines
4.3 KiB
JavaScript

/* 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/. */
let Cu = Components.utils;
let Ci = Components.interfaces;
let Cc = Components.classes;
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/Services.jsm");
const STORAGE_MAX_EVENTS = 200;
XPCOMUtils.defineLazyGetter(this, "gPrivBrowsing", function () {
// private browsing may not be available in some Gecko Apps
if (!(["@mozilla.org/privatebrowsing;1"] in Cc))
return null;
return Cc["@mozilla.org/privatebrowsing;1"].getService(Ci.nsIPrivateBrowsingService);
});
var EXPORTED_SYMBOLS = ["ConsoleAPIStorage"];
var _consoleStorage = {};
/**
* The ConsoleAPIStorage is meant to cache window.console API calls for later
* reuse by other components when needed. For example, the Web Console code can
* display the cached messages when it opens for the active tab.
*
* ConsoleAPI messages are stored as they come from the ConsoleAPI code, with
* all their properties. They are kept around until the inner window object that
* created the messages is destroyed. Messages are indexed by the inner window
* ID.
*
* Usage:
* Cu.import("resource://gre/modules/ConsoleAPIStorage.jsm");
*
* // Get the cached events array for the window you want (use the inner
* // window ID).
* let events = ConsoleAPIStorage.getEvents(innerWindowID);
* events.forEach(function(event) { ... });
*
* // Clear the events for the given inner window ID.
* ConsoleAPIStorage.clearEvents(innerWindowID);
*/
var ConsoleAPIStorage = {
QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver]),
/** @private */
observe: function CS_observe(aSubject, aTopic, aData)
{
if (aTopic == "xpcom-shutdown") {
Services.obs.removeObserver(this, "xpcom-shutdown");
Services.obs.removeObserver(this, "inner-window-destroyed");
Services.obs.removeObserver(this, "memory-pressure");
delete _consoleStorage;
}
else if (aTopic == "inner-window-destroyed") {
let innerWindowID = aSubject.QueryInterface(Ci.nsISupportsPRUint64).data;
this.clearEvents(innerWindowID);
}
else if (aTopic == "memory-pressure") {
if (aData == "low-memory") {
this.clearEvents();
}
}
},
/** @private */
init: function CS_init()
{
Services.obs.addObserver(this, "xpcom-shutdown", false);
Services.obs.addObserver(this, "inner-window-destroyed", false);
Services.obs.addObserver(this, "memory-pressure", false);
},
/**
* Get the events array by inner window ID.
*
* @param string aId
* The inner window ID for which you want to get the array of cached
* events.
* @returns array
* The array of cached events for the given window.
*/
getEvents: function CS_getEvents(aId)
{
return (_consoleStorage[aId] || []).slice(0);
},
/**
* Record an event associated with the given window ID.
*
* @param string aWindowID
* The ID of the inner window for which the event occurred.
* @param object aEvent
* A JavaScript object you want to store.
*/
recordEvent: function CS_recordEvent(aWindowID, aEvent)
{
let ID = parseInt(aWindowID);
if (isNaN(ID)) {
throw new Error("Invalid window ID argument");
}
if (gPrivBrowsing && gPrivBrowsing.privateBrowsingEnabled) {
return;
}
if (!_consoleStorage[ID]) {
_consoleStorage[ID] = [];
}
let storage = _consoleStorage[ID];
storage.push(aEvent);
// truncate
if (storage.length > STORAGE_MAX_EVENTS) {
storage.shift();
}
Services.obs.notifyObservers(aEvent, "console-storage-cache-event", ID);
},
/**
* Clear storage data for the given window.
*
* @param string [aId]
* Optional, the inner window ID for which you want to clear the
* messages. If this is not specified all of the cached messages are
* cleared, from all window objects.
*/
clearEvents: function CS_clearEvents(aId)
{
if (aId != null) {
delete _consoleStorage[aId];
}
else {
_consoleStorage = {};
Services.obs.notifyObservers(null, "console-storage-reset", null);
}
},
};
ConsoleAPIStorage.init();