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97 lines
3.2 KiB
C++
97 lines
3.2 KiB
C++
// Copyright 2014 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef MOJO_EDK_EMBEDDER_SIMPLE_PLATFORM_SHARED_BUFFER_H_
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#define MOJO_EDK_EMBEDDER_SIMPLE_PLATFORM_SHARED_BUFFER_H_
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#include <stddef.h>
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#include "mojo/edk/embedder/platform_shared_buffer.h"
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#include "mojo/edk/util/ref_ptr.h"
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#include "mojo/public/cpp/system/macros.h"
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namespace mojo {
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namespace embedder {
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// A simple implementation of |PlatformSharedBuffer|.
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class SimplePlatformSharedBuffer final : public PlatformSharedBuffer {
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public:
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// Creates a shared buffer of size |num_bytes| bytes (initially zero-filled).
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// |num_bytes| must be nonzero. Returns null on failure.
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static util::RefPtr<SimplePlatformSharedBuffer> Create(size_t num_bytes);
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static util::RefPtr<SimplePlatformSharedBuffer> CreateFromPlatformHandle(
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size_t num_bytes,
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platform::ScopedPlatformHandle platform_handle);
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// |PlatformSharedBuffer| implementation:
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size_t GetNumBytes() const override;
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std::unique_ptr<PlatformSharedBufferMapping> Map(size_t offset,
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size_t length) override;
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bool IsValidMap(size_t offset, size_t length) override;
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std::unique_ptr<PlatformSharedBufferMapping> MapNoCheck(
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size_t offset,
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size_t length) override;
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platform::ScopedPlatformHandle DuplicatePlatformHandle() override;
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platform::ScopedPlatformHandle PassPlatformHandle() override;
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private:
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explicit SimplePlatformSharedBuffer(size_t num_bytes);
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~SimplePlatformSharedBuffer() override;
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// This is called by |Create()| before this object is given to anyone.
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bool Init();
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// This is like |Init()|, but for |CreateFromPlatformHandle()|. (Note: It
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// should verify that |platform_handle| is an appropriate handle for the
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// claimed |num_bytes_|.)
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bool InitFromPlatformHandle(platform::ScopedPlatformHandle platform_handle);
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const size_t num_bytes_;
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// This is set in |Init()|/|InitFromPlatformHandle()| and never modified
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// (except by |PassPlatformHandle()|; see the comments above its declaration),
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// hence does not need to be protected by a lock.
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platform::ScopedPlatformHandle handle_;
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MOJO_DISALLOW_COPY_AND_ASSIGN(SimplePlatformSharedBuffer);
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};
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// An implementation of |PlatformSharedBufferMapping|, produced by
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// |SimplePlatformSharedBuffer|.
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class SimplePlatformSharedBufferMapping final
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: public PlatformSharedBufferMapping {
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public:
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~SimplePlatformSharedBufferMapping() override;
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void* GetBase() const override;
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size_t GetLength() const override;
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private:
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friend class SimplePlatformSharedBuffer;
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SimplePlatformSharedBufferMapping(void* base,
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size_t length,
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void* real_base,
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size_t real_length)
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: base_(base),
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length_(length),
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real_base_(real_base),
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real_length_(real_length) {}
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void Unmap();
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void* const base_;
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const size_t length_;
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void* const real_base_;
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const size_t real_length_;
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MOJO_DISALLOW_COPY_AND_ASSIGN(SimplePlatformSharedBufferMapping);
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};
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} // namespace embedder
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} // namespace mojo
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#endif // MOJO_EDK_EMBEDDER_SIMPLE_PLATFORM_SHARED_BUFFER_H_
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