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      1 // Copyright (c) 2012 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 WEBKIT_BROWSER_BLOB_LOCAL_FILE_STREAM_READER_H_
      6 #define WEBKIT_BROWSER_BLOB_LOCAL_FILE_STREAM_READER_H_
      7 
      8 #include "base/basictypes.h"
      9 #include "base/compiler_specific.h"
     10 #include "base/files/file_path.h"
     11 #include "base/memory/weak_ptr.h"
     12 #include "base/platform_file.h"
     13 #include "base/time/time.h"
     14 #include "webkit/browser/blob/file_stream_reader.h"
     15 #include "webkit/browser/webkit_storage_browser_export.h"
     16 
     17 namespace base {
     18 class TaskRunner;
     19 }
     20 
     21 namespace net {
     22 class FileStream;
     23 }
     24 
     25 namespace webkit_blob {
     26 
     27 // A thin wrapper of net::FileStream with range support for sliced file
     28 // handling.
     29 class WEBKIT_STORAGE_BROWSER_EXPORT LocalFileStreamReader
     30     : public FileStreamReader {
     31  public:
     32   // Creates a new FileReader for a local file |file_path|.
     33   // |initial_offset| specifies the offset in the file where the first read
     34   // should start.  If the given offset is out of the file range any
     35   // read operation may error out with net::ERR_REQUEST_RANGE_NOT_SATISFIABLE.
     36   //
     37   // |expected_modification_time| specifies the expected last modification
     38   // If the value is non-null, the reader will check the underlying file's
     39   // actual modification time to see if the file has been modified, and if
     40   // it does any succeeding read operations should fail with
     41   // ERR_UPLOAD_FILE_CHANGED error.
     42   LocalFileStreamReader(base::TaskRunner* task_runner,
     43                         const base::FilePath& file_path,
     44                         int64 initial_offset,
     45                         const base::Time& expected_modification_time);
     46   virtual ~LocalFileStreamReader();
     47 
     48   // FileStreamReader overrides.
     49   virtual int Read(net::IOBuffer* buf, int buf_len,
     50                    const net::CompletionCallback& callback) OVERRIDE;
     51   virtual int64 GetLength(
     52       const net::Int64CompletionCallback& callback) OVERRIDE;
     53 
     54  private:
     55   int Open(const net::CompletionCallback& callback);
     56 
     57   // Callbacks that are chained from Open for Read.
     58   void DidVerifyForOpen(const net::CompletionCallback& callback,
     59                         int64 get_length_result);
     60   void DidOpenFileStream(const net::CompletionCallback& callback,
     61                          int result);
     62   void DidSeekFileStream(const net::CompletionCallback& callback,
     63                          int64 seek_result);
     64   void DidOpenForRead(net::IOBuffer* buf,
     65                       int buf_len,
     66                       const net::CompletionCallback& callback,
     67                       int open_result);
     68 
     69   void DidGetFileInfoForGetLength(const net::Int64CompletionCallback& callback,
     70                                   base::PlatformFileError error,
     71                                   const base::PlatformFileInfo& file_info);
     72 
     73   scoped_refptr<base::TaskRunner> task_runner_;
     74   scoped_ptr<net::FileStream> stream_impl_;
     75   const base::FilePath file_path_;
     76   const int64 initial_offset_;
     77   const base::Time expected_modification_time_;
     78   bool has_pending_open_;
     79   base::WeakPtrFactory<LocalFileStreamReader> weak_factory_;
     80 };
     81 
     82 }  // namespace webkit_blob
     83 
     84 #endif  // WEBKIT_BROWSER_BLOB_LOCAL_FILE_STREAM_READER_H_
     85