components/persistent_cache/entry.h

// Copyright 2024 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_PERSISTENT_CACHE_ENTRY_H_
#define COMPONENTS_PERSISTENT_CACHE_ENTRY_H_

#include <stdint.h>

#include "base/compiler_specific.h"
#include "base/component_export.h"
#include "base/containers/span.h"
#include "components/persistent_cache/entry_metadata.h"

namespace persistent_cache {

// Provides access to a snapshot of the content of an entry. The snapshot
// remains valid and unmodified even if the entry is modified or removed in the
// cache.
class COMPONENT_EXPORT(PERSISTENT_CACHE) Entry {
 public:
  virtual ~Entry() = 0;

  // Not copyable or moveable.
  Entry(const Entry&) = delete;
  Entry(Entry&&) = delete;
  Entry& operator=(const Entry&) = delete;
  Entry& operator=(Entry&&) = delete;

  // Returns a span over the entry's contents.
  virtual base::span<const uint8_t> GetContentSpan() const LIFETIME_BOUND = 0;

  // Returns the size of the entry's contents in bytes.
  virtual size_t GetContentSize() const;

  // Returns the entry's metadata. Partially or completely populated by default
  // values if the metadata was not supplied on insert.
  virtual EntryMetadata GetMetadata() const = 0;

 protected:
  // Ownership and liveness is managed by the backend and thus Entry should not
  // be created outside of their scope.
  Entry() = default;
};

}  // namespace persistent_cache

#endif  // COMPONENTS_PERSISTENT_CACHE_ENTRY_H_