1 files changed, 180 insertions, 0 deletions
diff --git a/toolkit/mozapps/webextensions/internal/LightweightThemeImageOptimizer.jsm b/toolkit/mozapps/webextensions/internal/LightweightThemeImageOptimizer.jsm
new file mode 100644
index 000000000..49dfa237f
--- /dev/null
+++ b/toolkit/mozapps/webextensions/internal/LightweightThemeImageOptimizer.jsm
@@ -0,0 +1,180 @@
+/* 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";
+
+this.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;
+
+this.LightweightThemeImageOptimizer = {
+  optimize: function(aThemeData, aScreen) {
+    let data = Object.assign({}, 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() {
+    let dir = FileUtils.getDir("ProfD", ["lwtheme"]);
+    dir.followLinks = false;
+    try {
+      dir.remove(true);
+    } catch (e) {}
+  }
+};
+
+Object.freeze(LightweightThemeImageOptimizer);
+
+var ImageCropper = {
+  _inProgress: {},
+
+  getCroppedImageURL: function(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(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();
+    });
+  }
+};
+
+var ImageFile = {
+  read: function(aURI, aCallback) {
+    this._netUtil.asyncFetch({
+      uri: aURI,
+      loadUsingSystemPrincipal: true,
+      contentPolicyType: Ci.nsIContentPolicy.TYPE_INTERNAL_IMAGE
+    }, 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(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");
+
+var ImageTools = {
+  decode: function(aInputStream, aContentType) {
+    let outParam = {value: null};
+
+    try {
+      this._imgTools.decodeImageData(aInputStream, aContentType, outParam);
+    } catch (e) {}
+
+    return outParam.value;
+  },
+
+  encode: function(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");
+