Issue 7257 - Throttle badge updates

lib/stats.js

Index: lib/stats.js
===================================================================
--- a/lib/stats.js
+++ b/lib/stats.js
@@ -20,79 +20,159 @@
 "use strict";
 
 const {Prefs} = require("./prefs");
 const {BlockingFilter} = require("../adblockpluscore/lib/filterClasses");
 const {filterNotifier} = require("../adblockpluscore/lib/filterNotifier");
 const {port} = require("./messaging");
 
 const badgeColor = "#646464";
+
+// 4 fps.
+const badgeRefreshRate = 4;
+
 let blockedPerPage = new ext.PageMap();
 
 let getBlockedPerPage =
 /**
  * Gets the number of requests blocked on the given page.
  *
  * @param  {Page} page
  * @return {Number}
  */
 exports.getBlockedPerPage = page => blockedPerPage.get(page) || 0;
 
-function updateBadge(page, blockedCount)
+// The ID of the focused window. If all windows lose focus, this is the ID of
+// the last focused window.
+let focusedWindowId = -1;
+
+// The ID of the active tab in the focused window. This can be unknown (-1) on
+// startup and (briefly) when the focus shifts to a different window.
+let activeTabId = -1;
+
+let Scheduler = function()
 {
-  if (Prefs.show_statsinicon)
+  this.scheduled = false;
+};
+Scheduler.prototype = {
+  schedule(delay, func)
   {
-    page.browserAction.setBadge(blockedCount && {
-      color: badgeColor,
-      number: blockedCount
-    });
+    setTimeout(() =>
+    {
+      this.scheduled = false;
+      func();
+    },
+    delay);
+
+    this.scheduled = true;
   }
+};
+
+let badgeUpdateScheduler = new Scheduler();
+
+function updateBadgeNow()
+{
+  if (activeTabId == -1)
+    return;
+
+  let page = new ext.Page({id: activeTabId});
+  let blockedCount = blockedPerPage.get(page);
+
+  page.browserAction.setBadge(blockedCount && {
+    color: badgeColor,
+    number: blockedCount
+  });
+}
+
+function updateBadge(tabId = -1)
+{
+  if (!badgeUpdateScheduler.scheduled &&
+      (tabId == activeTabId || tabId == -1) && activeTabId != -1 &&
+      Prefs.show_statsinicon)
+  {
+    // Schedule an update.
+    badgeUpdateScheduler.schedule(1000 / badgeRefreshRate, updateBadgeNow);
+  }
+}
+
+function findAndUpdateActiveTab()
+{
+  browser.tabs.query({active: true, lastFocusedWindow: true}, ([tab]) =>
+  {
+    if (tab && activeTabId != tab.id)
+    {
+      activeTabId = tab.id;
+      focusedWindowId = tab.windowId;
+
+      updateBadge();
+    }
+  });
 }
 
 // Once nagivation for the tab has been committed to (e.g. it's no longer
 // being prerendered) we clear its badge, or if some requests were already
 // blocked beforehand we display those on the badge now.
 browser.webNavigation.onCommitted.addListener(details =>
 {
   if (details.frameId == 0)
-  {
-    let page = new ext.Page({id: details.tabId});
-    let blocked = blockedPerPage.get(page);
-
-    updateBadge(page, blocked);
-  }
+    updateBadge(details.tabId);
 });
 
 filterNotifier.on("filter.hitCount", (filter, newValue, oldValue, tabIds) =>
 {
   if (!(filter instanceof BlockingFilter))
     return;
 
   for (let tabId of tabIds)
   {
     let page = new ext.Page({id: tabId});
     let blocked = blockedPerPage.get(page) || 0;
 
     blockedPerPage.set(page, ++blocked);
-    updateBadge(page, blocked);
+    updateBadge(tabId);
   }
 
   Prefs.blocked_total++;
 });
 
 Prefs.on("show_statsinicon", () =>
 {
   browser.tabs.query({}, tabs =>
   {
     for (let tab of tabs)
     {
       let page = new ext.Page(tab);
 
       if (Prefs.show_statsinicon)
-        updateBadge(page, blockedPerPage.get(page));
+        updateBadge(tab.id);
       else
         page.browserAction.setBadge(null);
     }
   });
 });
 
 port.on("stats.getBlockedPerPage",
         message => getBlockedPerPage(new ext.Page(message.tab)));
+
+browser.tabs.onActivated.addListener(tab =>
+{
+  if (tab.windowId == focusedWindowId && activeTabId != tab.tabId)
+  {
+    activeTabId = tab.tabId;
+    updateBadge();
+  }
+});
+
+if ("windows" in browser)
+{
+  browser.windows.onFocusChanged.addListener(windowId =>
+  {
+    if (windowId == browser.windows.WINDOW_ID_NONE)
+      return;
+
+    focusedWindowId = windowId;
+    activeTabId = -1;
+
+    findAndUpdateActiveTab();
+  });
+}
+
+findAndUpdateActiveTab();