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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.
#ifndef REMOTING_CAPTURER_SHARED_BUFFER_H_
#define REMOTING_CAPTURER_SHARED_BUFFER_H_
#include "base/basictypes.h"
#include "base/memory/ref_counted.h"
#include "base/process.h"
#include "base/shared_memory.h"
namespace remoting {
// Represents a memory buffer that can be shared between multiple processes.
// It is more or less a convenience wrapper around base::SharedMemory providing
// ref-counted lifetime management and unique buffer identifiers.
class SharedBuffer
: public base::RefCountedThreadSafe<SharedBuffer> {
public:
// Creates a new shared memory buffer of the given size and maps it to
// the memory of the calling process. If the operation fails for any reason,
// ptr() method will return NULL. This constructor set the identifier of this
// buffer to 0.
explicit SharedBuffer(uint32 size);
// Opens an existing shared memory buffer and maps it to the memory of
// the calling process (in read only mode). If the operation fails for any
// reason, ptr() method will return NULL.
SharedBuffer(int id, base::SharedMemoryHandle handle, uint32 size);
// Opens an existing shared memory buffer created by a different process and
// maps it to the memory of the calling process (in read only mode). If
// the operation fails for any reason, ptr() method will return NULL.
SharedBuffer(int id, base::SharedMemoryHandle handle,
base::ProcessHandle process, uint32 size);
// Returns pointer to the beginning of the allocated data buffer. Returns NULL
// if the object initialization failed for any reason.
void* ptr() const { return shared_memory_.memory(); }
// Returns handle of the shared memory section containing the allocated
// data buffer.
base::SharedMemoryHandle handle() const { return shared_memory_.handle(); }
int id() const { return id_; }
uint32 size() const { return size_; }
void set_id(int id) { id_ = id; }
private:
friend class base::RefCountedThreadSafe<SharedBuffer>;
virtual ~SharedBuffer();
// Unique identifier of the buffer or 0 if ID hasn't been set.
int id_;
// Shared memory section backing up the buffer.
base::SharedMemory shared_memory_;
// Size of the buffer in bytes.
uint32 size_;
DISALLOW_COPY_AND_ASSIGN(SharedBuffer);
};
} // namespace remoting
#endif // REMOTING_CAPTURER_SHARED_BUFFER_H_
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