Linux: implement Page Actions support.

chrome/browser/image_loading_tracker.cc

+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/image_loading_tracker.h"
+
+#include "app/gfx/favicon_size.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/message_loop.h"
+#include "base/scoped_ptr.h"
+#include "base/task.h"
+#include "base/thread.h"
+#include "chrome/browser/browser_process.h"
+#include "skia/ext/image_operations.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "webkit/glue/image_decoder.h"
+
+////////////////////////////////////////////////////////////////////////////////
+// ImageLoadingTracker::LoadImageTask
+
+// The LoadImageTask is for asynchronously loading the image on the file thread.
+// If the image is successfully loaded and decoded it will report back on the
+// |callback_loop| to let the caller know the image is done loading.
+class ImageLoadingTracker::LoadImageTask : public Task {
+ public:
+  // Constructor for the LoadImageTask class. |tracker| is the object that
+  // we use to communicate back to the entity that wants the image after we
+  // decode it. |path| is the path to load the image from. |index| is an
+  // identifier for the image that we pass back to the caller.
+  LoadImageTask(ImageLoadingTracker* tracker,
+                const FilePath& path,
+                size_t index)
+    : callback_loop_(MessageLoop::current()),
+      tracker_(tracker),
+      path_(path),
+      index_(index) {}
+
+  void ReportBack(SkBitmap* image) {
+    DCHECK(image);
+    callback_loop_->PostTask(FROM_HERE, NewRunnableMethod(tracker_,
+        &ImageLoadingTracker::OnImageLoaded,
+        image,
+        index_));
+  }
+
+  virtual void Run() {
+    // Read the file from disk.
+    std::string file_contents;
+    if (!file_util::PathExists(path_) ||
+        !file_util::ReadFileToString(path_, &file_contents)) {
+      ReportBack(NULL);
+      return;
+    }
+
+    // Decode the image using WebKit's image decoder.
+    const unsigned char* data =
+        reinterpret_cast<const unsigned char*>(file_contents.data());
+    webkit_glue::ImageDecoder decoder(gfx::Size(kFavIconSize, kFavIconSize));
+    scoped_ptr<SkBitmap> decoded(new SkBitmap());
+    *decoded = decoder.Decode(data, file_contents.length());
+    if (decoded->empty()) {
+      ReportBack(NULL);
+      return;  // Unable to decode.
+    }
+
+    if (decoded->width() != kFavIconSize || decoded->height() != kFavIconSize) {
+      // The bitmap is not the correct size, re-sample.
+      int new_width = decoded->width();
+      int new_height = decoded->height();
+      // Calculate what dimensions to use within the constraints (16x16 max).
+      calc_favicon_target_size(&new_width, &new_height);
+      *decoded = skia::ImageOperations::Resize(
+          *decoded, skia::ImageOperations::RESIZE_LANCZOS3,
+          new_width, new_height);
+    }
+
+    ReportBack(decoded.release());
+  }
+
+ private:
+  // The message loop that we need to call back on to report that we are done.
+  MessageLoop* callback_loop_;
+
+  // The object that is waiting for us to respond back.
+  ImageLoadingTracker* tracker_;
+
+  // The path to the image to load asynchronously.
+  FilePath path_;
+
+  // The index of the icon being loaded.
+  size_t index_;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+// ImageLoadingTracker
+
+void ImageLoadingTracker::PostLoadImageTask(FilePath path) {
+  MessageLoop* file_loop = g_browser_process->file_thread()->message_loop();
+  file_loop->PostTask(FROM_HERE, new LoadImageTask(this, path,
+                                                   posted_count_++));
+}
+
+void ImageLoadingTracker::OnImageLoaded(SkBitmap* image, size_t index) {
+  if (image == NULL) {
+    NOTREACHED() << "Image failed to decode.";
+    image = new SkBitmap();
+  }
+  if (observer_)
+    observer_->OnImageLoaded(image, index);
+  delete image;
+  if (--image_count_ == 0)
+    Release();  // We are no longer needed.
+}