Reorganize net/disk_cache into backend specific directories.

net/disk_cache/file.h

-// Copyright (c) 2012 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.
-
-// See net/disk_cache/disk_cache.h for the public interface of the cache.
-
-#ifndef NET_DISK_CACHE_FILE_H_
-#define NET_DISK_CACHE_FILE_H_
-
-#include "base/memory/ref_counted.h"
-#include "base/platform_file.h"
-#include "net/base/net_export.h"
-
-namespace base {
-class FilePath;
-}
-
-namespace disk_cache {
-
-// This interface is used to support asynchronous ReadData and WriteData calls.
-class FileIOCallback {
- public:
-  // Notified of the actual number of bytes read or written. This value is
-  // negative if an error occurred.
-  virtual void OnFileIOComplete(int bytes_copied) = 0;
-
- protected:
-  virtual ~FileIOCallback() {}
-};
-
-// Simple wrapper around a file that allows asynchronous operations.
-class NET_EXPORT_PRIVATE File : public base::RefCounted<File> {
-  friend class base::RefCounted<File>;
- public:
-  File();
-  // mixed_mode set to true enables regular synchronous operations for the file.
-  explicit File(bool mixed_mode);
-
-  // Initializes the object to use the passed in file instead of opening it with
-  // the Init() call. No asynchronous operations can be performed with this
-  // object.
-  explicit File(base::PlatformFile file);
-
-  // Initializes the object to point to a given file. The file must aready exist
-  // on disk, and allow shared read and write.
-  bool Init(const base::FilePath& name);
-
-  // Returns the handle or file descriptor.
-  base::PlatformFile platform_file() const;
-
-  // Returns true if the file was opened properly.
-  bool IsValid() const;
-
-  // Performs synchronous IO.
-  bool Read(void* buffer, size_t buffer_len, size_t offset);
-  bool Write(const void* buffer, size_t buffer_len, size_t offset);
-
-  // Performs asynchronous IO. callback will be called when the IO completes,
-  // as an APC on the thread that queued the operation.
-  bool Read(void* buffer, size_t buffer_len, size_t offset,
-            FileIOCallback* callback, bool* completed);
-  bool Write(const void* buffer, size_t buffer_len, size_t offset,
-             FileIOCallback* callback, bool* completed);
-
-  // Sets the file's length. The file is truncated or extended with zeros to
-  // the new length.
-  bool SetLength(size_t length);
-  size_t GetLength();
-
-  // Blocks until |num_pending_io| IO operations complete.
-  static void WaitForPendingIO(int* num_pending_io);
-
-  // Drops current pending operations without waiting for them to complete.
-  static void DropPendingIO();
-
- protected:
-  virtual ~File();
-
- private:
-  // Performs the actual asynchronous write. If notify is set and there is no
-  // callback, the call will be re-synchronized.
-  bool AsyncWrite(const void* buffer, size_t buffer_len, size_t offset,
-                  FileIOCallback* callback, bool* completed);
-
-  // Infrastructure for async IO.
-  int DoRead(void* buffer, size_t buffer_len, size_t offset);
-  int DoWrite(const void* buffer, size_t buffer_len, size_t offset);
-  void OnOperationComplete(FileIOCallback* callback, int result);
-
-  bool init_;
-  bool mixed_;
-  base::PlatformFile platform_file_;  // Regular, asynchronous IO handle.
-  base::PlatformFile sync_platform_file_;  // Synchronous IO handle.
-
-  DISALLOW_COPY_AND_ASSIGN(File);
-};
-
-}  // namespace disk_cache
-
-#endif  // NET_DISK_CACHE_FILE_H_