webkit/fileapi/local_file_stream_writer.h

   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_FILEAPI_LOCAL_FILE_STREAM_WRITER_H_
   6 #define WEBKIT_FILEAPI_LOCAL_FILE_STREAM_WRITER_H_
   7
   8 #include <utility>
   9
  10 #include "base/callback.h"
  11 #include "base/compiler_specific.h"
  12 #include "base/files/file_path.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/memory/weak_ptr.h"
  15 #include "base/platform_file.h"
  16 #include "webkit/fileapi/file_stream_writer.h"
  17 #include "webkit/storage/webkit_storage_export.h"
  18
  19 namespace net {
  20 class FileStream;
  21 }
  22
  23 namespace fileapi {
  24
  25 // This class is a thin wrapper around net::FileStream for writing local files.
  26 class WEBKIT_STORAGE_EXPORT_PRIVATE LocalFileStreamWriter
  27     : public FileStreamWriter {
  28  public:
  29   // Create a writer for the existing file in the path |file_path| starting from
  30   // |initial_offset|.
  31   LocalFileStreamWriter(const base::FilePath& file_path, int64 initial_offset);
  32   virtual ~LocalFileStreamWriter();
  33
  34   // FileStreamWriter overrides.
  35   virtual int Write(net::IOBuffer* buf, int buf_len,
  36                     const net::CompletionCallback& callback) OVERRIDE;
  37   virtual int Cancel(const net::CompletionCallback& callback) OVERRIDE;
  38   virtual int Flush(const net::CompletionCallback& callback) OVERRIDE;
  39
  40  private:
  41   // Opens |file_path_| and if it succeeds, proceeds to InitiateSeek().
  42   // If failed, the error code is returned by calling |error_callback|.
  43   int InitiateOpen(const net::CompletionCallback& error_callback,
  44                    const base::Closure& main_operation);
  45   void DidOpen(const net::CompletionCallback& error_callback,
  46                const base::Closure& main_operation,
  47                int result);
  48
  49   // Seeks to |initial_offset_| and proceeds to |main_operation| if it succeeds.
  50   // If failed, the error code is returned by calling |error_callback|.
  51   void InitiateSeek(const net::CompletionCallback& error_callback,
  52                     const base::Closure& main_operation);
  53   void DidSeek(const net::CompletionCallback& error_callback,
  54                const base::Closure& main_operation,
  55                int64 result);
  56
  57   // Passed as the |main_operation| of InitiateOpen() function.
  58   void ReadyToWrite(net::IOBuffer* buf, int buf_len,
  59                     const net::CompletionCallback& callback);
  60
  61   // Writes asynchronously to the file.
  62   int InitiateWrite(net::IOBuffer* buf, int buf_len,
  63                     const net::CompletionCallback& callback);
  64   void DidWrite(const net::CompletionCallback& callback, int result);
  65
  66   // Flushes asynchronously to the file.
  67   int InitiateFlush(const net::CompletionCallback& callback);
  68   void DidFlush(const net::CompletionCallback& callback, int result);
  69
  70   // Stops the in-flight operation and calls |cancel_callback_| if it has been
  71   // set by Cancel() for the current operation.
  72   bool CancelIfRequested();
  73
  74   // Initialization parameters.
  75   const base::FilePath file_path_;
  76   const int64 initial_offset_;
  77
  78   // Current states of the operation.
  79   bool has_pending_operation_;
  80   scoped_ptr<net::FileStream> stream_impl_;
  81   net::CompletionCallback cancel_callback_;
  82
  83   base::WeakPtrFactory<LocalFileStreamWriter> weak_factory_;
  84   DISALLOW_COPY_AND_ASSIGN(LocalFileStreamWriter);
  85 };
  86
  87 }  // namespace fileapi
  88
  89 #endif  // WEBKIT_FILEAPI_LOCAL_FILE_STREAM_WRITER_H_