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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/. */
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
SessionStore: "resource:///modules/sessionstore/SessionStore.sys.mjs",
});
/**
* A module that enables async flushes. Updates from frame scripts are
* throttled to be sent only once per second. If an action wants a tab's latest
* state without waiting for a second then it can request an async flush and
* wait until the frame scripts reported back. At this point the parent has the
* latest data and the action can continue.
*/
export var TabStateFlusher = Object.freeze({
/**
* Requests an async flush for the given browser. Returns a promise that will
* resolve when we heard back from the content process and the parent has
* all the latest data.
*/
flush(browser) {
return TabStateFlusherInternal.flush(browser);
},
/**
* Requests an async flush for all browsers of a given window. Returns a Promise
* that will resolve when we've heard back from all browsers.
*/
flushWindow(window) {
return TabStateFlusherInternal.flushWindow(window);
},
/**
* Resolves the flush request with the given flush ID.
*
* @param browser (<xul:browser>)
* The browser for which the flush is being resolved.
* @param flushID (int)
* The ID of the flush that was sent to the browser.
* @param success (bool, optional)
* Whether or not the flush succeeded.
* @param message (string, optional)
* An error message that will be sent to the Console in the
* event that a flush failed.
*/
resolve(browser, flushID, success = true, message = "") {
TabStateFlusherInternal.resolve(browser, flushID, success, message);
},
/**
* Resolves all active flush requests for a given browser. This should be
* used when the content process crashed or the final update message was
* seen. In those cases we can't guarantee to ever hear back from the frame
* script so we just resolve all requests instead of discarding them.
*
* @param browser (<xul:browser>)
* The browser for which all flushes are being resolved.
* @param success (bool, optional)
* Whether or not the flushes succeeded.
* @param message (string, optional)
* An error message that will be sent to the Console in the
* event that the flushes failed.
*/
resolveAll(browser, success = true, message = "") {
TabStateFlusherInternal.resolveAll(browser, success, message);
},
});
var TabStateFlusherInternal = {
// Stores the last request ID.
_lastRequestID: 0,
// A map storing all active requests per browser. A request is a
// triple of a map containing all flush requests, a promise that
// resolve when a request for a browser is canceled, and the
// function to call to cancel a reqeust.
_requests: new WeakMap(),
initEntry(entry) {
entry.perBrowserRequests = new Map();
entry.cancelPromise = new Promise(resolve => {
entry.cancel = resolve;
}).then(result => {
TabStateFlusherInternal.initEntry(entry);
return result;
});
return entry;
},
/**
* Requests an async flush for the given browser. Returns a promise that will
* resolve when we heard back from the content process and the parent has
* all the latest data.
*/
flush(browser) {
let id = ++this._lastRequestID;
let nativePromise = Promise.resolve();
if (browser && browser.frameLoader) {
/*
Request native listener to flush the tabState.
Resolves when flush is complete.
*/
nativePromise = browser.frameLoader.requestTabStateFlush();
}
if (!Services.appinfo.sessionHistoryInParent) {
/*
In the event that we have to trigger a process switch and thus change
browser remoteness, session store needs to register and track the new
browser window loaded and to have message manager listener registered
** before ** TabStateFlusher send "SessionStore:flush" message. This fixes
the race where we send the message before the message listener is
registered for it.
*/
lazy.SessionStore.ensureInitialized(browser.ownerGlobal);
let mm = browser.messageManager;
mm.sendAsyncMessage("SessionStore:flush", {
id,
epoch: lazy.SessionStore.getCurrentEpoch(browser),
});
}
// Retrieve active requests for given browser.
let permanentKey = browser.permanentKey;
let request = this._requests.get(permanentKey);
if (!request) {
// If we don't have any requests for this browser, create a new
// entry for browser.
request = this.initEntry({});
this._requests.set(permanentKey, request);
}
// Non-SHIP flushes resolve this after the "SessionStore:update" message. We
// don't use that message for SHIP, so it's fine to resolve the request
// immediately after the native promise resolves, since SessionStore will
// have processed all updates from this browser by that point.
let requestPromise = Promise.resolve();
if (!Services.appinfo.sessionHistoryInParent) {
requestPromise = new Promise(resolve => {
// Store resolve() so that we can resolve the promise later.
request.perBrowserRequests.set(id, resolve);
});
}
return Promise.race([
nativePromise.then(_ => requestPromise),
request.cancelPromise,
]);
},
/**
* Requests an async flush for all non-lazy browsers of a given window.
* Returns a Promise that will resolve when we've heard back from all browsers.
*/
flushWindow(window) {
let promises = [];
for (let browser of window.gBrowser.browsers) {
if (window.gBrowser.getTabForBrowser(browser).linkedPanel) {
promises.push(this.flush(browser));
}
}
return Promise.all(promises);
},
/**
* Resolves the flush request with the given flush ID.
*
* @param browser (<xul:browser>)
* The browser for which the flush is being resolved.
* @param flushID (int)
* The ID of the flush that was sent to the browser.
* @param success (bool, optional)
* Whether or not the flush succeeded.
* @param message (string, optional)
* An error message that will be sent to the Console in the
* event that a flush failed.
*/
resolve(browser, flushID, success = true, message = "") {
// Nothing to do if there are no pending flushes for the given browser.
if (!this._requests.has(browser.permanentKey)) {
return;
}
// Retrieve active requests for given browser.
let { perBrowserRequests } = this._requests.get(browser.permanentKey);
if (!perBrowserRequests.has(flushID)) {
return;
}
if (!success) {
Cu.reportError("Failed to flush browser: " + message);
}
// Resolve the request with the given id.
let resolve = perBrowserRequests.get(flushID);
perBrowserRequests.delete(flushID);
resolve(success);
},
/**
* Resolves all active flush requests for a given browser. This should be
* used when the content process crashed or the final update message was
* seen. In those cases we can't guarantee to ever hear back from the frame
* script so we just resolve all requests instead of discarding them.
*
* @param browser (<xul:browser>)
* The browser for which all flushes are being resolved.
* @param success (bool, optional)
* Whether or not the flushes succeeded.
* @param message (string, optional)
* An error message that will be sent to the Console in the
* event that the flushes failed.
*/
resolveAll(browser, success = true, message = "") {
// Nothing to do if there are no pending flushes for the given browser.
if (!this._requests.has(browser.permanentKey)) {
return;
}
// Retrieve the cancel function for a given browser.
let { cancel } = this._requests.get(browser.permanentKey);
if (!success) {
Cu.reportError("Failed to flush browser: " + message);
}
// Resolve all requests.
cancel(success);
},
};
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