1 files changed, 224 insertions, 0 deletions
diff --git a/browser/base/content/browser-thumbnails.js b/browser/base/content/browser-thumbnails.js
new file mode 100644
index 0000000000..e17f5aa05b
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+++ b/browser/base/content/browser-thumbnails.js
@@ -0,0 +1,224 @@
+/* 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/. */
+
+// This file is loaded into the browser window scope.
+/* eslint-env mozilla/browser-window */
+
+/**
+ * Keeps thumbnails of open web pages up-to-date.
+ */
+var gBrowserThumbnails = {
+  /**
+   * Pref that controls whether we can store SSL content on disk
+   */
+  PREF_DISK_CACHE_SSL: "browser.cache.disk_cache_ssl",
+
+  _captureDelayMS: 1000,
+
+  /**
+   * Used to keep track of disk_cache_ssl preference
+   */
+  _sslDiskCacheEnabled: null,
+
+  /**
+   * Map of capture() timeouts assigned to their browsers.
+   */
+  _timeouts: null,
+
+  /**
+   * Top site URLs refresh timer.
+   */
+  _topSiteURLsRefreshTimer: null,
+
+  /**
+   * List of tab events we want to listen for.
+   */
+  _tabEvents: ["TabClose", "TabSelect"],
+
+  init: function Thumbnails_init() {
+    gBrowser.addTabsProgressListener(this);
+    Services.prefs.addObserver(this.PREF_DISK_CACHE_SSL, this);
+
+    this._sslDiskCacheEnabled = Services.prefs.getBoolPref(
+      this.PREF_DISK_CACHE_SSL
+    );
+
+    this._tabEvents.forEach(function (aEvent) {
+      gBrowser.tabContainer.addEventListener(aEvent, this);
+    }, this);
+
+    this._timeouts = new WeakMap();
+  },
+
+  uninit: function Thumbnails_uninit() {
+    gBrowser.removeTabsProgressListener(this);
+    Services.prefs.removeObserver(this.PREF_DISK_CACHE_SSL, this);
+
+    if (this._topSiteURLsRefreshTimer) {
+      this._topSiteURLsRefreshTimer.cancel();
+      this._topSiteURLsRefreshTimer = null;
+    }
+
+    this._tabEvents.forEach(function (aEvent) {
+      gBrowser.tabContainer.removeEventListener(aEvent, this);
+    }, this);
+  },
+
+  handleEvent: function Thumbnails_handleEvent(aEvent) {
+    switch (aEvent.type) {
+      case "scroll":
+        let browser = aEvent.currentTarget;
+        if (this._timeouts.has(browser)) {
+          this._delayedCapture(browser);
+        }
+        break;
+      case "TabSelect":
+        this._delayedCapture(aEvent.target.linkedBrowser);
+        break;
+      case "TabClose": {
+        this._cancelDelayedCapture(aEvent.target.linkedBrowser);
+        break;
+      }
+    }
+  },
+
+  observe: function Thumbnails_observe(subject, topic, data) {
+    switch (data) {
+      case this.PREF_DISK_CACHE_SSL:
+        this._sslDiskCacheEnabled = Services.prefs.getBoolPref(
+          this.PREF_DISK_CACHE_SSL
+        );
+        break;
+    }
+  },
+
+  clearTopSiteURLCache: function Thumbnails_clearTopSiteURLCache() {
+    if (this._topSiteURLsRefreshTimer) {
+      this._topSiteURLsRefreshTimer.cancel();
+      this._topSiteURLsRefreshTimer = null;
+    }
+    // Delete the defined property
+    delete this._topSiteURLs;
+    XPCOMUtils.defineLazyGetter(this, "_topSiteURLs", getTopSiteURLs);
+  },
+
+  notify: function Thumbnails_notify(timer) {
+    gBrowserThumbnails._topSiteURLsRefreshTimer = null;
+    gBrowserThumbnails.clearTopSiteURLCache();
+  },
+
+  /**
+   * State change progress listener for all tabs.
+   */
+  onStateChange: function Thumbnails_onStateChange(
+    aBrowser,
+    aWebProgress,
+    aRequest,
+    aStateFlags,
+    aStatus
+  ) {
+    if (
+      aStateFlags & Ci.nsIWebProgressListener.STATE_STOP &&
+      aStateFlags & Ci.nsIWebProgressListener.STATE_IS_NETWORK
+    ) {
+      this._delayedCapture(aBrowser);
+    }
+  },
+
+  async _capture(aBrowser) {
+    // Only capture about:newtab top sites.
+    const topSites = await this._topSiteURLs;
+    if (!aBrowser.currentURI || !topSites.includes(aBrowser.currentURI.spec)) {
+      return;
+    }
+    if (await this._shouldCapture(aBrowser)) {
+      await PageThumbs.captureAndStoreIfStale(aBrowser);
+    }
+  },
+
+  _delayedCapture: function Thumbnails_delayedCapture(aBrowser) {
+    if (this._timeouts.has(aBrowser)) {
+      this._cancelDelayedCallbacks(aBrowser);
+    } else {
+      aBrowser.addEventListener("scroll", this, true);
+    }
+
+    let idleCallback = () => {
+      this._cancelDelayedCapture(aBrowser);
+      this._capture(aBrowser);
+    };
+
+    // setTimeout to set a guarantee lower bound for the requestIdleCallback
+    // (and therefore the delayed capture)
+    let timeoutId = setTimeout(() => {
+      let idleCallbackId = requestIdleCallback(idleCallback, {
+        timeout: this._captureDelayMS * 30,
+      });
+      this._timeouts.set(aBrowser, { isTimeout: false, id: idleCallbackId });
+    }, this._captureDelayMS);
+
+    this._timeouts.set(aBrowser, { isTimeout: true, id: timeoutId });
+  },
+
+  _shouldCapture: async function Thumbnails_shouldCapture(aBrowser) {
+    // Capture only if it's the currently selected tab and not an about: page.
+    if (
+      aBrowser != gBrowser.selectedBrowser ||
+      gBrowser.currentURI.schemeIs("about")
+    ) {
+      return false;
+    }
+    return PageThumbs.shouldStoreThumbnail(aBrowser);
+  },
+
+  _cancelDelayedCapture: function Thumbnails_cancelDelayedCapture(aBrowser) {
+    if (this._timeouts.has(aBrowser)) {
+      aBrowser.removeEventListener("scroll", this);
+      this._cancelDelayedCallbacks(aBrowser);
+      this._timeouts.delete(aBrowser);
+    }
+  },
+
+  _cancelDelayedCallbacks: function Thumbnails_cancelDelayedCallbacks(
+    aBrowser
+  ) {
+    let timeoutData = this._timeouts.get(aBrowser);
+
+    if (timeoutData.isTimeout) {
+      clearTimeout(timeoutData.id);
+    } else {
+      // idle callback dispatched
+      window.cancelIdleCallback(timeoutData.id);
+    }
+  },
+};
+
+async function getTopSiteURLs() {
+  // The _topSiteURLs getter can be expensive to run, but its return value can
+  // change frequently on new profiles, so as a compromise we cache its return
+  // value as a lazy getter for 1 minute every time it's called.
+  gBrowserThumbnails._topSiteURLsRefreshTimer = Cc[
+    "@mozilla.org/timer;1"
+  ].createInstance(Ci.nsITimer);
+  gBrowserThumbnails._topSiteURLsRefreshTimer.initWithCallback(
+    gBrowserThumbnails,
+    60 * 1000,
+    Ci.nsITimer.TYPE_ONE_SHOT
+  );
+  let sites = [];
+  // Get both the top sites returned by the query, and also any pinned sites
+  // that the user might have added manually that also need a screenshot.
+  // Also include top sites that don't have rich icons
+  let topSites = await NewTabUtils.activityStreamLinks.getTopSites();
+  sites.push(...topSites.filter(link => !(link.faviconSize >= 96)));
+  sites.push(...NewTabUtils.pinnedLinks.links);
+  return sites.reduce((urls, link) => {
+    if (link) {
+      urls.push(link.url);
+    }
+    return urls;
+  }, []);
+}
+
+XPCOMUtils.defineLazyGetter(gBrowserThumbnails, "_topSiteURLs", getTopSiteURLs);