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// Copyright 2013 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.
#ifndef CHROME_BROWSER_CHROMEOS_DRIVE_LOCAL_FILE_READER_H_
#define CHROME_BROWSER_CHROMEOS_DRIVE_LOCAL_FILE_READER_H_
#include "base/basictypes.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/platform_file.h"
#include "net/base/completion_callback.h"
namespace base {
class FilePath;
class SequencedTaskRunner;
} // namespace base
namespace net {
class IOBuffer;
} // namespace
namespace drive {
namespace util {
// This is simple local file reader implementation focusing on Drive's use
// case. All the operations run on |sequenced_task_runner| asynchronously and
// the result will be notified to the caller via |callback|s on the caller's
// thread.
class LocalFileReader {
public:
explicit LocalFileReader(base::SequencedTaskRunner* sequenced_task_runner);
~LocalFileReader();
// Opens the file at |file_path|. The initial position of the read will be
// at |offset| from the beginning of the file.
// Upon completion, |callback| will be called.
// |callback| must not be null.
void Open(const base::FilePath& file_path,
int64 offset,
const net::CompletionCallback& callback);
// Reads the file and copies the data into |buffer|. |buffer_length|
// is the length of |buffer|.
// Upon completion, |callback| will be called with the result.
// |callback| must not be null.
void Read(net::IOBuffer* buffer,
int buffer_length,
const net::CompletionCallback& callback);
private:
// The thin wrapper for the platform file to handle closing correctly.
class ScopedPlatformFile;
// Part of Open(). Called after the open() operation task running
// on blocking pool.
void OpenAfterBlockingPoolTask(
const net::CompletionCallback& callback,
ScopedPlatformFile* result_platform_file,
int open_result);
scoped_refptr<base::SequencedTaskRunner> sequenced_task_runner_;
base::PlatformFile platform_file_;
// Note: This should remain the last member so it'll be destroyed and
// invalidate the weak pointers before any other members are destroyed.
base::WeakPtrFactory<LocalFileReader> weak_ptr_factory_;
DISALLOW_COPY_AND_ASSIGN(LocalFileReader);
};
} // namespace util
} // namespace drive
#endif // CHROME_BROWSER_CHROMEOS_DRIVE_LOCAL_FILE_READER_H_
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