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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 STORAGE_MAX_EVENTS = 1000;
var _consoleStorage = new Map();
// NOTE: these listeners used to just be added as observers and notified via
// Services.obs.notifyObservers. However, that has enough overhead to be a
// problem for this. Using an explicit global array is much cheaper, and
// should be equivalent.
var _logEventListeners = [];
const CONSOLEAPISTORAGE_CID = Components.ID(
"{96cf7855-dfa9-4c6d-8276-f9705b4890f2}"
);
/**
* 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:
* let ConsoleAPIStorage = Cc["@mozilla.org/consoleAPI-storage;1"]
* .getService(Ci.nsIConsoleAPIStorage);
*
* // 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);
*/
function ConsoleAPIStorageService() {
this.init();
}
ConsoleAPIStorageService.prototype = {
classID: CONSOLEAPISTORAGE_CID,
QueryInterface: ChromeUtils.generateQI([
"nsIConsoleAPIStorage",
"nsIObserver",
]),
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");
} else if (aTopic == "inner-window-destroyed") {
let innerWindowID = aSubject.QueryInterface(Ci.nsISupportsPRUint64).data;
this.clearEvents(innerWindowID + "");
} else if (aTopic == "memory-pressure") {
this.clearEvents();
}
},
/** @private */
init: function CS_init() {
Services.obs.addObserver(this, "xpcom-shutdown");
Services.obs.addObserver(this, "inner-window-destroyed");
Services.obs.addObserver(this, "memory-pressure");
},
/**
* Get the events array by inner window ID or all events from all windows.
*
* @param string [aId]
* Optional, 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. If no |aId| is
* given this function returns all of the cached events, from any
* window.
*/
getEvents: function CS_getEvents(aId) {
if (aId != null) {
return (_consoleStorage.get(aId) || []).slice(0);
}
let result = [];
for (let [, events] of _consoleStorage) {
result.push.apply(result, events);
}
return result.sort(function(a, b) {
return a.timeStamp - b.timeStamp;
});
},
/**
* Adds a listener to be notified of log events.
*
* @param jsval [aListener]
* A JS listener which will be notified with the message object when
* a log event occurs.
* @param nsIPrincipal [aPrincipal]
* The principal of the listener - used to determine if we need to
* clone the message before forwarding it.
*/
addLogEventListener: function CS_addLogEventListener(aListener, aPrincipal) {
// If our listener has a less-privileged principal than us, then they won't
// be able to access the log event object which was populated for our
// scope. Accordingly we need to clone it for these listeners.
//
// XXX: AFAICT these listeners which we need to clone messages for are all
// tests. Alternative solutions are welcome.
const clone = !aPrincipal.subsumes(
Cc["@mozilla.org/systemprincipal;1"].createInstance(Ci.nsIPrincipal)
);
_logEventListeners.push({
callback: aListener,
clone,
});
},
/**
* Removes a listener added with `addLogEventListener`.
*
* @param jsval [aListener]
* A JS listener which was added with `addLogEventListener`.
*/
removeLogEventListener: function CS_removeLogEventListener(aListener) {
const index = _logEventListeners.findIndex(l => l.callback === aListener);
if (index != -1) {
_logEventListeners.splice(index, 1);
} else {
console.error(
"Attempted to remove a log event listener that does not exist."
);
}
},
/**
* Record an event associated with the given window ID.
*
* @param string aId
* The ID of the inner window for which the event occurred or "jsm" for
* messages logged from JavaScript modules..
* @param object aEvent
* A JavaScript object you want to store.
*/
recordEvent: function CS_recordEvent(aId, aEvent) {
if (!_consoleStorage.has(aId)) {
_consoleStorage.set(aId, []);
}
let storage = _consoleStorage.get(aId);
storage.push(aEvent);
// truncate
if (storage.length > STORAGE_MAX_EVENTS) {
storage.shift();
}
for (let { callback, clone } of _logEventListeners) {
try {
if (clone) {
callback(Cu.cloneInto(aEvent, callback));
} else {
callback(aEvent);
}
} catch (e) {
// A failing listener should not prevent from calling other listeners.
console.error(e);
}
}
},
/**
* 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) {
_consoleStorage.delete(aId);
} else {
_consoleStorage.clear();
Services.obs.notifyObservers(null, "console-storage-reset");
}
},
};
var EXPORTED_SYMBOLS = ["ConsoleAPIStorageService"];
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