naiveproxy/base/android/scoped_hardware_buffer_handle.h
2018-08-14 22:19:20 +00:00

88 lines
3.2 KiB
C++

// Copyright 2018 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 BASE_ANDROID_SCOPED_HARDWARE_BUFFER_HANDLE_H_
#define BASE_ANDROID_SCOPED_HARDWARE_BUFFER_HANDLE_H_
#include "base/base_export.h"
#include "base/files/scoped_file.h"
#include "base/macros.h"
extern "C" typedef struct AHardwareBuffer AHardwareBuffer;
namespace base {
namespace android {
// Owns a single reference to an AHardwareBuffer object.
class BASE_EXPORT ScopedHardwareBufferHandle {
public:
ScopedHardwareBufferHandle();
// Takes ownership of |other|'s buffer reference. Does NOT acquire a new one.
ScopedHardwareBufferHandle(ScopedHardwareBufferHandle&& other);
// Releases this handle's reference to the underlying buffer object if still
// valid.
~ScopedHardwareBufferHandle();
// Assumes ownership of an existing reference to |buffer|. This does NOT
// acquire a new reference.
static ScopedHardwareBufferHandle Adopt(AHardwareBuffer* buffer);
// Takes ownership of |other|'s buffer reference. Does NOT acquire a new one.
ScopedHardwareBufferHandle& operator=(ScopedHardwareBufferHandle&& other);
bool is_valid() const;
AHardwareBuffer* get() const;
// Releases this handle's reference to the underlying buffer object if still
// valid. Invalidates this handle.
void reset();
// Passes implicit ownership of this handle's reference over to the caller,
// invalidating |this|. Returns the raw buffer handle.
//
// The caller is responsible for eventually releasing this reference to the
// buffer object.
AHardwareBuffer* Take() WARN_UNUSED_RESULT;
// Creates a new handle with its own newly acquired reference to the
// underlying buffer object. |this| must be a valid handle.
ScopedHardwareBufferHandle Clone() const;
// Consumes a handle and returns a file descriptor which can be used to
// transmit the handle over IPC. A subsequent receiver may use
// |DeserializeFromFileDescriptor()| to recover the buffer handle.
//
// NOTE: The returned file descriptor DOES NOT own a reference to the
// underlying AHardwareBuffer. When using this for IPC, the caller is
// responsible for retaining at least one reference to the buffer object to
// keep it alive while the descriptor is in transit.
ScopedFD SerializeAsFileDescriptor() const;
// Consumes the supplied single-use file descriptor (which must have been
// returned by a previous call to |SerializeAsFileDescriptor()|, perhaps in
// a different process), and recovers an AHardwareBuffer object from it.
//
// This acquires a new reference to the AHardwareBuffer, with ownership passed
// to the caller via the returned ScopedHardwareBufferHandle.
static ScopedHardwareBufferHandle DeserializeFromFileDescriptor(ScopedFD fd)
WARN_UNUSED_RESULT;
private:
// Assumes ownership of an existing reference to |buffer|. This does NOT
// acquire a new reference.
explicit ScopedHardwareBufferHandle(AHardwareBuffer* buffer);
AHardwareBuffer* buffer_ = nullptr;
DISALLOW_COPY_AND_ASSIGN(ScopedHardwareBufferHandle);
};
} // namespace android
} // namespace base
#endif // BASE_ANDROID_SCOPED_HARDWARE_BUFFER_HANDLE_H_