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// Copyright 2008, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// 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 <string>
#include "base/ref_counted.h"
#include "net/disk_cache/os_file.h"
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;
virtual ~FileIOCallback() {}
};
// Simple wrapper around a file that allows asynchronous operations.
class File : public base::RefCounted<File> {
friend class base::RefCounted<File>;
public:
File() : init_(false), mixed_(false) {}
// mixed_mode set to true enables regular synchronous operations for the file.
explicit File(bool mixed_mode) : init_(false), mixed_(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(OSFile 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 std::wstring& name);
// Returns the handle or file descriptor.
OSFile os_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);
// Performs asynchronous writes, but doesn't notify when done. Automatically
// deletes buffer when done.
bool PostWrite(const void* buffer, size_t buffer_len, size_t offset);
// 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();
protected:
virtual ~File();
// 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,
bool notify, FileIOCallback* callback, bool* completed);
private:
bool init_;
bool mixed_;
OSFile os_file_; // Regular, asynchronous IO handle.
OSFile sync_os_file_; // Synchronous IO hanlde.
DISALLOW_COPY_AND_ASSIGN(File);
};
} // namespace disk_cache
#endif // NET_DISK_CACHE_FILE_H_
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