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// Copyright 2014 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 MOJO_EDK_EMBEDDER_SIMPLE_PLATFORM_SHARED_BUFFER_H_
#define MOJO_EDK_EMBEDDER_SIMPLE_PLATFORM_SHARED_BUFFER_H_
#include <stddef.h>
#include "mojo/edk/embedder/platform_shared_buffer.h"
#include "mojo/edk/system/system_impl_export.h"
#include "mojo/public/cpp/system/macros.h"
namespace mojo {
namespace edk {
// A simple implementation of |PlatformSharedBuffer|.
class MOJO_SYSTEM_IMPL_EXPORT SimplePlatformSharedBuffer final
: public PlatformSharedBuffer {
public:
// Creates a shared buffer of size |num_bytes| bytes (initially zero-filled).
// |num_bytes| must be nonzero. Returns null on failure.
static SimplePlatformSharedBuffer* Create(size_t num_bytes);
static SimplePlatformSharedBuffer* CreateFromPlatformHandle(
size_t num_bytes,
ScopedPlatformHandle platform_handle);
// |PlatformSharedBuffer| implementation:
size_t GetNumBytes() const override;
scoped_ptr<PlatformSharedBufferMapping> Map(size_t offset,
size_t length) override;
bool IsValidMap(size_t offset, size_t length) override;
scoped_ptr<PlatformSharedBufferMapping> MapNoCheck(size_t offset,
size_t length) override;
ScopedPlatformHandle DuplicatePlatformHandle() override;
ScopedPlatformHandle PassPlatformHandle() override;
private:
explicit SimplePlatformSharedBuffer(size_t num_bytes);
~SimplePlatformSharedBuffer() override;
// Implemented in simple_platform_shared_buffer_{posix,win}.cc:
// This is called by |Create()| before this object is given to anyone.
bool Init();
// This is like |Init()|, but for |CreateFromPlatformHandle()|. (Note: It
// should verify that |platform_handle| is an appropriate handle for the
// claimed |num_bytes_|.)
bool InitFromPlatformHandle(ScopedPlatformHandle platform_handle);
// The platform-dependent part of |Map()|; doesn't check arguments.
scoped_ptr<PlatformSharedBufferMapping> MapImpl(size_t offset, size_t length);
const size_t num_bytes_;
// This is set in |Init()|/|InitFromPlatformHandle()| and never modified
// (except by |PassPlatformHandle()|; see the comments above its declaration),
// hence does not need to be protected by a lock.
ScopedPlatformHandle handle_;
MOJO_DISALLOW_COPY_AND_ASSIGN(SimplePlatformSharedBuffer);
};
// An implementation of |PlatformSharedBufferMapping|, produced by
// |SimplePlatformSharedBuffer|.
class MOJO_SYSTEM_IMPL_EXPORT SimplePlatformSharedBufferMapping
: public PlatformSharedBufferMapping {
public:
~SimplePlatformSharedBufferMapping() override;
void* GetBase() const override;
size_t GetLength() const override;
private:
friend class SimplePlatformSharedBuffer;
SimplePlatformSharedBufferMapping(void* base,
size_t length,
void* real_base,
size_t real_length)
: base_(base),
length_(length),
real_base_(real_base),
real_length_(real_length) {}
void Unmap();
void* const base_;
const size_t length_;
void* const real_base_;
const size_t real_length_;
MOJO_DISALLOW_COPY_AND_ASSIGN(SimplePlatformSharedBufferMapping);
};
} // namespace edk
} // namespace mojo
#endif // MOJO_EDK_EMBEDDER_SIMPLE_PLATFORM_SHARED_BUFFER_H_
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