fix #23: detect a pre-exisitng facebook container

If a user installed multi-account-containers, they may already have
facebook.com assigned to a container. We detect that assignment, and
don't do anything else so we don't mess up their existing assignments.

background.js

@@ -1,65 +1,98 @@
-let facebookCookieStoreId = null;
-
 // Param values from https://developer.mozilla.org/Add-ons/WebExtensions/API/contextualIdentities/create
 const FACEBOOK_CONTAINER_NAME = "Facebook";
 const FACEBOOK_CONTAINER_COLOR = "blue";
 const FACEBOOK_CONTAINER_ICON = "briefcase";
-const FACEBOOK_DOMAINS = ["facebook.com", "fb.com"];
+const FACEBOOK_DOMAINS = ["facebook.com", "www.facebook.com", "fb.com"];
 
-const facebookHostREs = [];
+let facebookCookieStoreId = null;
 
-for (let facebookDomain of FACEBOOK_DOMAINS) {
-  facebookHostREs.push(new RegExp(`^(.*)?${facebookDomain}$`));
-  const facebookCookieUrl = `https://${facebookDomain}/`;
+const facebookHostREs = [];
 
-  browser.cookies.getAll({domain: facebookDomain}).then(cookies => {
-    for (let cookie of cookies) {
-      browser.cookies.remove({name: cookie.name, url: facebookCookieUrl});
+async function isFacebookAlreadyAssignedInMAC () {
+  let anyFBDomainsAssigned = false;
+  for (let facebookDomain of FACEBOOK_DOMAINS) {
+    const facebookCookieUrl = `https://${facebookDomain}/`;
+    let assignment;
+    try {
+      assignment = await browser.runtime.sendMessage("@testpilot-containers", {
+        method: "getAssignment",
+        url: facebookCookieUrl
+      });
+    } catch (e) {
+      return false;
     }
-  });
+    if (assignment) {
+      anyFBDomainsAssigned = true;
+    }
+  }
+  return anyFBDomainsAssigned;
 }
 
-browser.contextualIdentities.query({name: FACEBOOK_CONTAINER_NAME}).then(contexts => {
-  if (contexts.length > 0) {
-    facebookCookieStoreId = contexts[0].cookieStoreId;
-  } else {
-    browser.contextualIdentities.create({
-      name: FACEBOOK_CONTAINER_NAME,
-      color: FACEBOOK_CONTAINER_COLOR,
-      icon: FACEBOOK_CONTAINER_ICON}
-    ).then(context => {
-      facebookCookieStoreId = context.cookieStoreId;
+(async function init() {
+  const facebookAlreadyAssigned = await isFacebookAlreadyAssignedInMAC();
+  if (facebookAlreadyAssigned) {
+    return;
+  }
+
+  // Clear all facebook cookies
+  for (let facebookDomain of FACEBOOK_DOMAINS) {
+    facebookHostREs.push(new RegExp(`^(.*)?${facebookDomain}$`));
+    const facebookCookieUrl = `https://${facebookDomain}/`;
+
+    browser.cookies.getAll({domain: facebookDomain}).then(cookies => {
+      for (let cookie of cookies) {
+        browser.cookies.remove({name: cookie.name, url: facebookCookieUrl});
+      }
     });
   }
-});
 
-async function containFacebook(options) {
-  const requestUrl = new URL(options.url);
-  let isFacebook = false;
-  for (let facebookHostRE of facebookHostREs) {
-    if (facebookHostRE.test(requestUrl.host)) {
-      isFacebook = true;
-      break;
+  // Use existing Facebook container, or create one
+  browser.contextualIdentities.query({name: FACEBOOK_CONTAINER_NAME}).then(contexts => {
+    if (contexts.length > 0) {
+      facebookCookieStoreId = contexts[0].cookieStoreId;
+    } else {
+      browser.contextualIdentities.create({
+        name: FACEBOOK_CONTAINER_NAME,
+        color: FACEBOOK_CONTAINER_COLOR,
+        icon: FACEBOOK_CONTAINER_ICON}
+      ).then(context => {
+        facebookCookieStoreId = context.cookieStoreId;
+      });
     }
-  }
-  const tab = await browser.tabs.get(options.tabId);
-  const tabCookieStoreId = tab.cookieStoreId;
-  if (isFacebook) {
-    if (tabCookieStoreId !== facebookCookieStoreId && !tab.incognito) {
-      // See https://github.com/mozilla/contain-facebook/issues/23
-      // Sometimes this add-on is installed but doesn't get a facebookCookieStoreId ?
-      if (facebookCookieStoreId) {
-        browser.tabs.create({url: requestUrl.toString(), cookieStoreId: facebookCookieStoreId});
+  });
+
+  // Listen to requests and open Facebook into its Container,
+  // open other sites into the default tab context
+  async function containFacebook(options) {
+    const requestUrl = new URL(options.url);
+    let isFacebook = false;
+    for (let facebookHostRE of facebookHostREs) {
+      if (facebookHostRE.test(requestUrl.host)) {
+        isFacebook = true;
+        break;
+      }
+    }
+    const tab = await browser.tabs.get(options.tabId);
+    const tabCookieStoreId = tab.cookieStoreId;
+    if (isFacebook) {
+      if (tabCookieStoreId !== facebookCookieStoreId && !tab.incognito) {
+        // See https://github.com/mozilla/contain-facebook/issues/23
+        // Sometimes this add-on is installed but doesn't get a facebookCookieStoreId ?
+        if (facebookCookieStoreId) {
+          browser.tabs.create({url: requestUrl.toString(), cookieStoreId: facebookCookieStoreId});
+          browser.tabs.remove(options.tabId);
+          return {cancel: true};
+        }
+      }
+    } else {
+      if (tabCookieStoreId === facebookCookieStoreId) {
+        browser.tabs.create({url: requestUrl.toString()});
         browser.tabs.remove(options.tabId);
         return {cancel: true};
       }
     }
-  } else {
-    if (tabCookieStoreId === facebookCookieStoreId) {
-      browser.tabs.create({url: requestUrl.toString()});
-      browser.tabs.remove(options.tabId);
-      return {cancel: true};
-    }
   }
-}
-browser.webRequest.onBeforeRequest.addListener(containFacebook, {urls: ["<all_urls>"], types: ["main_frame"]}, ["blocking"]);
+
+  // Add the request listener
+  browser.webRequest.onBeforeRequest.addListener(containFacebook, {urls: ["<all_urls>"], types: ["main_frame"]}, ["blocking"]);
+})();