Bug 650968 - Enabling a lightweight theme (Persona) causes significant startup slowness; r=felipe

toolkit/content/LightweightThemeConsumer.jsm

@@ -4,10 +4,20 @@
 
 let EXPORTED_SYMBOLS = ["LightweightThemeConsumer"];
 
+Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "LightweightThemeImageOptimizer",
+  "resource://gre/modules/LightweightThemeImageOptimizer.jsm");
+
 function LightweightThemeConsumer(aDocument) {
   this._doc = aDocument;
+  this._win = aDocument.defaultView;
   this._footerId = aDocument.documentElement.getAttribute("lightweightthemesfooter");
 
+  let screen = this._win.screen;
+  this._lastScreenWidth = screen.width;
+  this._lastScreenHeight = screen.height;
+
   Components.classes["@mozilla.org/observer-service;1"]
             .getService(Components.interfaces.nsIObserverService)
             .addObserver(this, "lightweight-theme-styling-update", false);
@@ -15,9 +25,14 @@ function LightweightThemeConsumer(aDocument) {
   var temp = {};
   Components.utils.import("resource://gre/modules/LightweightThemeManager.jsm", temp);
   this._update(temp.LightweightThemeManager.currentThemeForDisplay);
+  this._win.addEventListener("resize", this);
 }
 
 LightweightThemeConsumer.prototype = {
+  _lastData: null,
+  _lastScreenWidth: null,
+  _lastScreenHeight: null,
+
   observe: function (aSubject, aTopic, aData) {
     if (aTopic != "lightweight-theme-styling-update")
       return;
@@ -25,18 +40,32 @@ LightweightThemeConsumer.prototype = {
     this._update(JSON.parse(aData));
   },
 
+  handleEvent: function (aEvent) {
+    let {width, height} = this._win.screen;
+
+    if (this._lastScreenWidth != width || this._lastScreenHeight != height) {
+      this._lastScreenWidth = width;
+      this._lastScreenHeight = height;
+      this._update(this._lastData);
+    }
+  },
+
   destroy: function () {
     Components.classes["@mozilla.org/observer-service;1"]
               .getService(Components.interfaces.nsIObserverService)
               .removeObserver(this, "lightweight-theme-styling-update");
 
-    this._doc = null;
+    this._win.removeEventListener("resize", this);
+    this._win = this._doc = null;
   },
 
   _update: function (aData) {
     if (!aData)
       aData = { headerURL: "", footerURL: "", textcolor: "", accentcolor: "" };
 
+    this._lastData = aData;
+    aData = LightweightThemeImageOptimizer.optimize(aData, this._win.screen);
+
     var root = this._doc.documentElement;
     var active = !!aData.headerURL;
 

toolkit/mozapps/extensions/LightweightThemeImageOptimizer.jsm

@@ -0,0 +1,186 @@
+/* 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/. */
+
+"use strict";
+
+let EXPORTED_SYMBOLS = ["LightweightThemeImageOptimizer"];
+
+const Cu = Components.utils;
+const Ci = Components.interfaces;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "Services",
+  "resource://gre/modules/Services.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "FileUtils",
+  "resource://gre/modules/FileUtils.jsm");
+
+const ORIGIN_TOP_RIGHT = 1;
+const ORIGIN_BOTTOM_LEFT = 2;
+
+let LightweightThemeImageOptimizer = {
+  optimize: function LWTIO_optimize(aThemeData, aScreen) {
+    let data = Utils.createCopy(aThemeData);
+    if (!data.headerURL) {
+      return data;
+    }
+
+    data.headerURL = ImageCropper.getCroppedImageURL(
+      data.headerURL, aScreen, ORIGIN_TOP_RIGHT);
+
+    if (data.footerURL) {
+      data.footerURL = ImageCropper.getCroppedImageURL(
+        data.footerURL, aScreen, ORIGIN_BOTTOM_LEFT);
+    }
+
+    return data;
+  },
+
+  purge: function LWTIO_purge() {
+    let dir = FileUtils.getDir("ProfD", ["lwtheme"]);
+    dir.followLinks = false;
+    try {
+      dir.remove(true);
+    } catch (e) {}
+  }
+};
+
+Object.freeze(LightweightThemeImageOptimizer);
+
+let ImageCropper = {
+  _inProgress: {},
+
+  getCroppedImageURL:
+  function ImageCropper_getCroppedImageURL(aImageURL, aScreen, aOrigin) {
+    // We can crop local files, only.
+    if (!aImageURL.startsWith("file://")) {
+      return aImageURL;
+    }
+
+    // Generate the cropped image's file name using its
+    // base name and the current screen size.
+    let uri = Services.io.newURI(aImageURL, null, null);
+    let file = uri.QueryInterface(Ci.nsIFileURL).file;
+
+    // Make sure the source file exists.
+    if (!file.exists()) {
+      return aImageURL;
+    }
+
+    let fileName = file.leafName + "-" + aScreen.width + "x" + aScreen.height;
+    let croppedFile = FileUtils.getFile("ProfD", ["lwtheme", fileName]);
+
+    // If we have a local file that is not in progress, return it.
+    if (croppedFile.exists() && !(croppedFile.path in this._inProgress)) {
+      let fileURI = Services.io.newFileURI(croppedFile);
+
+      // Copy the query part to avoid wrong caching.
+      fileURI.QueryInterface(Ci.nsIURL).query = uri.query;
+      return fileURI.spec;
+    }
+
+    // Crop the given image in the background.
+    this._crop(uri, croppedFile, aScreen, aOrigin);
+
+    // Return the original image while we're waiting for the cropped version
+    // to be written to disk.
+    return aImageURL;
+  },
+
+  _crop: function ImageCropper_crop(aURI, aTargetFile, aScreen, aOrigin) {
+    let inProgress = this._inProgress;
+    inProgress[aTargetFile.path] = true;
+
+    function resetInProgress() {
+      delete inProgress[aTargetFile.path];
+    }
+
+    ImageFile.read(aURI, function (aInputStream, aContentType) {
+      if (aInputStream && aContentType) {
+        let image = ImageTools.decode(aInputStream, aContentType);
+        if (image && image.width && image.height) {
+          let stream = ImageTools.encode(image, aScreen, aOrigin, aContentType);
+          if (stream) {
+            ImageFile.write(aTargetFile, stream, resetInProgress);
+            return;
+          }
+        }
+      }
+
+      resetInProgress();
+    });
+  }
+};
+
+let ImageFile = {
+  read: function ImageFile_read(aURI, aCallback) {
+    this._netUtil.asyncFetch(aURI, function (aInputStream, aStatus, aRequest) {
+      if (Components.isSuccessCode(aStatus) && aRequest instanceof Ci.nsIChannel) {
+        let channel = aRequest.QueryInterface(Ci.nsIChannel);
+        aCallback(aInputStream, channel.contentType);
+      } else {
+        aCallback();
+      }
+    });
+  },
+
+  write: function ImageFile_write(aFile, aInputStream, aCallback) {
+    let fos = FileUtils.openSafeFileOutputStream(aFile);
+    this._netUtil.asyncCopy(aInputStream, fos, function (aResult) {
+      FileUtils.closeSafeFileOutputStream(fos);
+
+      // Remove the file if writing was not successful.
+      if (!Components.isSuccessCode(aResult)) {
+        try {
+          aFile.remove(false);
+        } catch (e) {}
+      }
+
+      aCallback();
+    });
+  }
+};
+
+XPCOMUtils.defineLazyModuleGetter(ImageFile, "_netUtil",
+  "resource://gre/modules/NetUtil.jsm", "NetUtil");
+
+let ImageTools = {
+  decode: function ImageTools_decode(aInputStream, aContentType) {
+    let outParam = {value: null};
+
+    try {
+      this._imgTools.decodeImageData(aInputStream, aContentType, outParam);
+    } catch (e) {}
+
+    return outParam.value;
+  },
+
+  encode: function ImageTools_encode(aImage, aScreen, aOrigin, aContentType) {
+    let stream;
+    let width = Math.min(aImage.width, aScreen.width);
+    let height = Math.min(aImage.height, aScreen.height);
+    let x = aOrigin == ORIGIN_TOP_RIGHT ? aImage.width - width : 0;
+
+    try {
+      stream = this._imgTools.encodeCroppedImage(aImage, aContentType, x, 0,
+                                                 width, height);
+    } catch (e) {}
+
+    return stream;
+  }
+};
+
+XPCOMUtils.defineLazyServiceGetter(ImageTools, "_imgTools",
+  "@mozilla.org/image/tools;1", "imgITools");
+
+let Utils = {
+  createCopy: function Utils_createCopy(aData) {
+    let copy = {};
+    for (let [k, v] in Iterator(aData)) {
+      copy[k] = v;
+    }
+    return copy;
+  }
+};

toolkit/mozapps/extensions/LightweightThemeManager.jsm

@@ -9,6 +9,7 @@ var EXPORTED_SYMBOLS = ["LightweightThemeManager"];
 const Cc = Components.classes;
 const Ci = Components.interfaces;
 
+Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
 Components.utils.import("resource://gre/modules/AddonManager.jsm");
 Components.utils.import("resource://gre/modules/Services.jsm");
 
@@ -38,6 +39,9 @@ const PERSIST_FILES = {
   footerURL: "lightweighttheme-footer"
 };
 
+XPCOMUtils.defineLazyModuleGetter(this, "LightweightThemeImageOptimizer",
+  "resource://gre/modules/LightweightThemeImageOptimizer.jsm");
+
 __defineGetter__("_prefs", function () {
   delete this._prefs;
   return this._prefs = Services.prefs.getBranch("lightweightThemes.");
@@ -227,8 +231,12 @@ var LightweightThemeManager = {
       let usedThemes = _usedThemesExceptId(aData.id);
       usedThemes.unshift(aData);
       _updateUsedThemes(usedThemes);
-      if (PERSIST_ENABLED)
-        _persistImages(aData);
+      if (PERSIST_ENABLED) {
+        LightweightThemeImageOptimizer.purge();
+        _persistImages(aData, function () {
+          _notifyWindows(this.currentThemeForDisplay);
+        }.bind(this));
+      }
     }
 
     _prefs.setBoolPref("isThemeSelected", aData != null);
@@ -716,18 +724,25 @@ function _prefObserver(aSubject, aTopic, aData) {
   }
 }
 
-function _persistImages(aData) {
+function _persistImages(aData, aCallback) {
   function onSuccess(key) function () {
     let current = LightweightThemeManager.currentTheme;
-    if (current && current.id == aData.id)
+    if (current && current.id == aData.id) {
       _prefs.setBoolPref("persisted." + key, true);
+    }
+    if (--numFilesToPersist == 0 && aCallback) {
+      aCallback();
+    }
   };
 
+  let numFilesToPersist = 0;
   for (let key in PERSIST_FILES) {
     _prefs.setBoolPref("persisted." + key, false);
-    if (aData[key])
+    if (aData[key]) {
+      numFilesToPersist++;
       _persistImage(aData[key], PERSIST_FILES[key], onSuccess(key));
     }
+  }
 }
 
 function _getLocalImageURI(localFileName) {

toolkit/mozapps/extensions/Makefile.in

@@ -55,6 +55,7 @@ EXTRA_JS_MODULES = \
   AddonRepository.jsm \
   AddonUpdateChecker.jsm \
   ChromeManifestParser.jsm \
+  LightweightThemeImageOptimizer.jsm \
   LightweightThemeManager.jsm \
   PluginProvider.jsm \
   SpellCheckDictionaryBootstrap.js \