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      1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_USER_IMAGE_LOADER_H_
      6 #define CHROME_BROWSER_CHROMEOS_LOGIN_USER_IMAGE_LOADER_H_
      7 
      8 #include <map>
      9 #include <string>
     10 
     11 #include "base/callback.h"
     12 #include "base/compiler_specific.h"
     13 #include "base/memory/ref_counted.h"
     14 #include "base/synchronization/lock.h"
     15 #include "base/threading/sequenced_worker_pool.h"
     16 #include "chrome/browser/image_decoder.h"
     17 
     18 class SkBitmap;
     19 
     20 namespace base {
     21 class MessageLoop;
     22 }
     23 
     24 namespace chromeos {
     25 
     26 typedef base::SequencedWorkerPool::SequenceToken SequenceToken;
     27 
     28 class UserImage;
     29 
     30 // A facility to read a file containing user image asynchronously in the IO
     31 // thread. Returns the image in the form of an SkBitmap.
     32 class UserImageLoader : public base::RefCountedThreadSafe<UserImageLoader>,
     33                         public ImageDecoder::Delegate {
     34  public:
     35   // Callback used to indicate that image has been loaded.
     36   typedef base::Callback<void(const UserImage& user_image)> LoadedCallback;
     37 
     38   explicit UserImageLoader(ImageDecoder::ImageCodec image_codec);
     39 
     40   // Start reading the image from |filepath| on a worker thread pool. Calls
     41   // |loaded_cb| when image has been successfully loaded.
     42   // If |size| is positive, image is cropped and (if needed) downsized to
     43   // |size|x|size| pixels.
     44   void Start(const std::string& filepath, int size,
     45              const LoadedCallback& loaded_cb);
     46 
     47   // Start reading the image from |filepath| on a worker thread associated with
     48   // |token|. Calls |loaded_cb| when image has been successfully loaded.
     49   // If |size| is positive, image is cropped and (if needed) downsized to
     50   // |size|x|size| pixels.
     51   void Start(const std::string& filepath, int size,
     52              const SequenceToken& token,
     53              const LoadedCallback& loaded_cb);
     54 
     55  private:
     56   friend class base::RefCountedThreadSafe<UserImageLoader>;
     57 
     58   // Contains attributes we need to know about each image we decode.
     59   struct ImageInfo {
     60     ImageInfo(int size, const LoadedCallback& loaded_cb);
     61     ~ImageInfo();
     62 
     63     const int size;
     64     const LoadedCallback loaded_cb;
     65   };
     66 
     67   typedef std::map<const ImageDecoder*, ImageInfo> ImageInfoMap;
     68 
     69   virtual ~UserImageLoader();
     70 
     71   // Method that reads the file on the worker thread pool and starts decoding it
     72   // in a sandboxed process.
     73   void LoadImage(const std::string& filepath,
     74                  const ImageInfo& image_info,
     75                  scoped_refptr<base::SequencedTaskRunner> task_runner);
     76 
     77   // ImageDecoder::Delegate implementation.
     78   virtual void OnImageDecoded(const ImageDecoder* decoder,
     79                               const SkBitmap& decoded_image) OVERRIDE;
     80   virtual void OnDecodeImageFailed(const ImageDecoder* decoder) OVERRIDE;
     81 
     82   // The message loop object of the thread in which we notify the delegate.
     83   base::MessageLoop* target_message_loop_;
     84 
     85   // Specify how the file should be decoded in the utility process.
     86   const ImageDecoder::ImageCodec image_codec_;
     87 
     88   // Proctect image_info_map_
     89   base::Lock lock_;
     90 
     91   // Holds info structures about all images we're trying to decode.
     92   // Accessed on multiple worker threads.
     93   ImageInfoMap image_info_map_;
     94 
     95   DISALLOW_COPY_AND_ASSIGN(UserImageLoader);
     96 };
     97 
     98 }  // namespace chromeos
     99 
    100 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_USER_IMAGE_LOADER_H_
    101