Bug 1692124 - Guess the userContextId for externally opened URLs;r=mossop

Differential Revision: https://phabricator.services.mozilla.com/D154812

browser/base/content/browser.js

@@ -86,6 +86,7 @@ ChromeUtils.defineESModuleGetters(this, {
   TranslationsParent: "resource://gre/actors/TranslationsParent.sys.mjs",
   UITour: "resource:///modules/UITour.sys.mjs",
   UpdateUtils: "resource://gre/modules/UpdateUtils.sys.mjs",
+  URILoadingHelper: "resource:///modules/URILoadingHelper.sys.mjs",
   UrlbarInput: "resource:///modules/UrlbarInput.sys.mjs",
   UrlbarPrefs: "resource:///modules/UrlbarPrefs.sys.mjs",
   UrlbarProviderSearchTips:
@@ -6066,6 +6067,9 @@ nsBrowserAccess.prototype = {
   ) {
     var browsingContext = null;
     var isExternal = !!(aFlags & Ci.nsIBrowserDOMWindow.OPEN_EXTERNAL);
+    var openingUserContextId =
+      (isExternal && URILoadingHelper.guessUserContextId(aURI)) ||
+      Ci.nsIScriptSecurityManager.DEFAULT_USER_CONTEXT_ID;
 
     if (aOpenWindowInfo && isExternal) {
       console.error(
@@ -6171,7 +6175,7 @@ nsBrowserAccess.prototype = {
         let forceNotRemote = aOpenWindowInfo && !aOpenWindowInfo.isRemote;
         let userContextId = aOpenWindowInfo
           ? aOpenWindowInfo.originAttributes.userContextId
-          : Ci.nsIScriptSecurityManager.DEFAULT_USER_CONTEXT_ID;
+          : openingUserContextId;
         let browser = this._openURIInNewTab(
           aURI,
           referrerInfo,

browser/components/contextualidentity/test/browser/browser.toml

@@ -38,6 +38,8 @@ skip-if = ["true"] # Bug 1541885
 ["browser_imageCache.js"]
 skip-if = ["verify && debug && os == 'win'"]
 
+["browser_guessusercontext.js"]
+
 ["browser_middleClick.js"]
 skip-if = [
   "verify && debug && os == 'linux'",

browser/components/contextualidentity/test/browser/browser_guessusercontext.js

@@ -0,0 +1,80 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const PERSONAL = 1;
+const WORK = 2;
+const HOST_MOCHI = makeURI(
+  "http://mochi.test:8888/browser/browser/components/contextualidentity/test/browser/blank.html"
+);
+const HOST_EXAMPLE = makeURI(
+  "https://example.com/browser/browser/components/contextualidentity/test/browser/blank.html"
+);
+
+const {
+  URILoadingHelper: { guessUserContextId },
+} = ChromeUtils.importESModule("resource:///modules/URILoadingHelper.sys.mjs");
+
+async function openTabInUserContext(uri, userContextId, win = window) {
+  let { gBrowser } = win;
+  let tab = BrowserTestUtils.addTab(gBrowser, uri, { userContextId });
+  gBrowser.selectedTab = tab;
+  tab.ownerGlobal.focus();
+  await BrowserTestUtils.browserLoaded(gBrowser.getBrowserForTab(tab));
+  return tab;
+}
+
+registerCleanupFunction(async function cleanup() {
+  while (gBrowser.tabs.length > 1) {
+    gBrowser.removeTab(gBrowser.selectedTab, { animate: false });
+  }
+});
+
+add_setup(async function () {
+  await SpecialPowers.pushPrefEnv({
+    set: [["privacy.userContext.enabled", true]],
+  });
+});
+
+add_task(async function test() {
+  is(guessUserContextId(null), null, "invalid uri - null");
+  is(guessUserContextId(HOST_EXAMPLE), null, "no tabs - null");
+  await openTabInUserContext(HOST_EXAMPLE.spec, PERSONAL);
+  is(guessUserContextId(HOST_EXAMPLE), PERSONAL, "one tab - matches container");
+  is(guessUserContextId(HOST_MOCHI), null, "one tab - doesn't match container");
+  await openTabInUserContext(HOST_EXAMPLE.spec, WORK);
+  is(guessUserContextId(HOST_EXAMPLE), PERSONAL, "same number - use first");
+  await openTabInUserContext(HOST_EXAMPLE.spec, WORK);
+  is(guessUserContextId(HOST_EXAMPLE), WORK, "multiple per host - max");
+
+  let win = await BrowserTestUtils.openNewBrowserWindow();
+  await openTabInUserContext(HOST_EXAMPLE.spec, PERSONAL, win);
+  await openTabInUserContext(HOST_EXAMPLE.spec, PERSONAL, win);
+  is(guessUserContextId(HOST_EXAMPLE), PERSONAL, "count across windows");
+
+  await BrowserTestUtils.closeWindow(win);
+  is(guessUserContextId(HOST_EXAMPLE), WORK, "forgets closed window");
+
+  // Check the opener flow more directly
+  let browsingContext = window.browserDOMWindow.openURI(
+    makeURI(HOST_EXAMPLE.spec + "?new"),
+    null,
+    Ci.nsIBrowserDOMWindow.OPEN_NEWTAB,
+    Ci.nsIBrowserDOMWindow.OPEN_EXTERNAL,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+  await BrowserTestUtils.browserLoaded(browsingContext.embedderElement);
+  is(
+    browsingContext.embedderElement,
+    gBrowser.selectedBrowser,
+    "opener selected"
+  );
+  is(
+    gBrowser.selectedTab.getAttribute("usercontextid"),
+    WORK.toString(),
+    "opener flow"
+  );
+  is(guessUserContextId(HOST_EXAMPLE), WORK, "still the most common");
+  is(guessUserContextId(HOST_MOCHI), null, "still doesn't match container");
+});

browser/modules/URILoadingHelper.sys.mjs

@@ -735,4 +735,50 @@ export const URILoadingHelper = {
     params.forceForeground ??= true;
     this.openLinkIn(window, url, where, params);
   },
+
+  /**
+   * Given a URI, guess which container to use to open it. This is used for external
+   * openers as a quality of life improvement (e.g. to open a document into the container
+   * where you are logged in to the service that hosts it).
+   * matches will be returned.
+   * For now this can only use currently-open tabs, until history is tagged with the
+   * container id (https://bugzilla.mozilla.org/show_bug.cgi?id=1283320).
+   *
+   * @param {nsIURI} aURI - The URI being opened.
+   * @returns {number | null} The guessed userContextId, or null if none.
+   */
+  guessUserContextId(aURI) {
+    let host;
+    try {
+      host = aURI.host;
+    } catch (e) {}
+    if (!host) {
+      return null;
+    }
+    const containerScores = new Map();
+    let guessedUserContextId = null;
+    let maxCount = 0;
+    for (let win of lazy.BrowserWindowTracker.orderedWindows) {
+      for (let tab of win.gBrowser.visibleTabs) {
+        let { userContextId } = tab;
+        if (userContextId) {
+          let currentURIHost = null;
+          try {
+            currentURIHost = tab.linkedBrowser.currentURI.host;
+          } catch (e) {}
+
+          if (currentURIHost == host) {
+            let count = (containerScores.get(userContextId) ?? 0) + 1;
+            containerScores.set(userContextId, count);
+            if (count > maxCount) {
+              guessedUserContextId = userContextId;
+              maxCount = count;
+            }
+          }
+        }
+      }
+    }
+
+    return guessedUserContextId;
+  },
 };