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// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MOJO_CORE_IPCZ_DRIVER_SHARED_BUFFER_H_
#define MOJO_CORE_IPCZ_DRIVER_SHARED_BUFFER_H_
#include <cstdint>
#include "base/containers/span.h"
#include "base/memory/platform_shared_memory_region.h"
#include "base/memory/scoped_refptr.h"
#include "mojo/core/ipcz_driver/object.h"
#include "mojo/core/system_impl_export.h"
#include "mojo/public/cpp/platform/platform_handle.h"
namespace mojo::core::ipcz_driver {
// A SharedBuffer operates like Mojo Core's shared buffer object, as a weird
// thin wrapper around base's shared memory APIs. This exists to allow those
// objects to be boxed and transmitted through ipcz portals.
class MOJO_SYSTEM_IMPL_EXPORT SharedBuffer : public Object<SharedBuffer> {
public:
explicit SharedBuffer(base::subtle::PlatformSharedMemoryRegion region);
template <typename RegionType>
static scoped_refptr<SharedBuffer> MakeForRegion(RegionType region) {
return base::MakeRefCounted<SharedBuffer>(
RegionType::TakeHandleForSerialization(std::move(region)));
}
static constexpr Type object_type() { return kSharedBuffer; }
base::subtle::PlatformSharedMemoryRegion& region() { return region_; }
// Duplicates this buffer to a new buffer and returns a ref to the new object.
// The second return value is a result indicating success or failure. Anything
// other than IPCZ_RESULT_OK implies failure, and buffer must be null.
std::pair<scoped_refptr<SharedBuffer>, IpczResult> Duplicate(bool read_only);
// Helper to support the MojoWrapPlatformSharedMemoryRegion API.
static scoped_refptr<SharedBuffer> CreateForMojoWrapper(
base::span<const MojoPlatformHandle> mojo_platform_handles,
uint32_t size,
const MojoSharedBufferGuid& mojo_guid,
MojoPlatformSharedMemoryRegionAccessMode access);
// Object:
void Close() override;
bool IsSerializable() const override;
bool GetSerializedDimensions(Transport& transmitter,
size_t& num_bytes,
size_t& num_handles) override;
bool Serialize(Transport& transmitter,
base::span<uint8_t> data,
base::span<PlatformHandle> handles) override;
static scoped_refptr<SharedBuffer> Deserialize(
base::span<const uint8_t> data,
base::span<PlatformHandle> handles);
private:
~SharedBuffer() override;
base::subtle::PlatformSharedMemoryRegion region_;
};
} // namespace mojo::core::ipcz_driver
#endif // MOJO_CORE_IPCZ_DRIVER_SHARED_BUFFER_H_
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