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// 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();
// 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);
private:
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_
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