components/reporting/resources/resource_managed_buffer.h

// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_REPORTING_RESOURCES_RESOURCE_MANAGED_BUFFER_H_
#define COMPONENTS_REPORTING_RESOURCES_RESOURCE_MANAGED_BUFFER_H_

#include <cstdint>

#include "base/containers/heap_array.h"
#include "base/memory/scoped_refptr.h"
#include "components/reporting/resources/resource_manager.h"
#include "components/reporting/util/status.h"

namespace reporting {

// Helper class for memory buffer allocation, with memory availability
// controlled by resource manager. Calling `Allocate` would not initialize
// memory or preserve any existing data in the buffer. Not thread-safe, must be
// only used sequentially.
class ResourceManagedBuffer {
 public:
  explicit ResourceManagedBuffer(
      scoped_refptr<ResourceManager> memory_resource);

  ResourceManagedBuffer(ResourceManagedBuffer& other) = delete;
  ResourceManagedBuffer& operator=(ResourceManagedBuffer& other) = delete;

  ~ResourceManagedBuffer();

  Status Allocate(size_t size);

  void Clear();

  bool empty() const { return buffer_.empty(); }

  base::span<uint8_t> span() { return buffer_.as_span(); }

  base::span<uint8_t> subspan(size_t offset) { return buffer_.subspan(offset); }

  base::span<uint8_t> subspan(size_t offset, size_t size) {
    return buffer_.subspan(offset, size);
  }

  size_t size() const { return buffer_.size(); }

 private:
  base::HeapArray<uint8_t> buffer_;

  const scoped_refptr<ResourceManager> memory_resource_;
};

}  // namespace reporting

#endif  // COMPONENTS_REPORTING_RESOURCES_RESOURCE_MANAGED_BUFFER_H_