vulkan_handle.h

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// Copyright 2013 The Flutter 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 FLUTTER_VULKAN_PROCS_VULKAN_HANDLE_H_
#define FLUTTER_VULKAN_PROCS_VULKAN_HANDLE_H_
 
#include <functional>
 
#include "flutter/fml/logging.h"
#include "flutter/fml/macros.h"
#include "flutter/vulkan/procs/vulkan_interface.h"
 
namespace vulkan {
 
template <class T>
class VulkanHandle {
 public:
  using Handle = T;
  using Disposer = std::function<void(Handle)>;
 
  VulkanHandle() : handle_(VK_NULL_HANDLE) {}
 
  explicit VulkanHandle(Handle handle, const Disposer& disposer = nullptr)
      : handle_(handle), disposer_(disposer) {}
 
  VulkanHandle(VulkanHandle&& other)
      : handle_(other.handle_), disposer_(std::move(other.disposer_)) {
    other.handle_ = VK_NULL_HANDLE;
    other.disposer_ = nullptr;
  }
 
  ~VulkanHandle() { DisposeIfNecessary(); }
 
  VulkanHandle& operator=(VulkanHandle&& other) {
    if (handle_ != other.handle_) {
      DisposeIfNecessary();
    }
 
    handle_ = other.handle_;
    disposer_ = other.disposer_;
 
    other.handle_ = VK_NULL_HANDLE;
    other.disposer_ = nullptr;
 
    return *this;
  }
 
  explicit operator bool() const { return handle_ != VK_NULL_HANDLE; }
 
  // NOLINTNEXTLINE(google-explicit-constructor)
  operator Handle() const { return handle_; }
 
  /// Relinquish responsibility of collecting the underlying handle when this
  /// object is collected. It is the responsibility of the caller to ensure that
  /// the lifetime of the handle extends past the lifetime of this object.
  void ReleaseOwnership() { disposer_ = nullptr; }
 
  void Reset() { DisposeIfNecessary(); }
 
 private:
  Handle handle_;
  Disposer disposer_;
 
  void DisposeIfNecessary() {
    if (handle_ == VK_NULL_HANDLE) {
      return;
    }
    if (disposer_) {
      disposer_(handle_);
    }
    handle_ = VK_NULL_HANDLE;
    disposer_ = nullptr;
  }
 
  FML_DISALLOW_COPY_AND_ASSIGN(VulkanHandle);
};
 
}  // namespace vulkan
 
#endif  // FLUTTER_VULKAN_PROCS_VULKAN_HANDLE_H_