chunk_store_reader.h

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/*
 * Copyright 2026 The A11 Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#ifndef A11_STORES_CHUNK_STORE_READER_H_
#define A11_STORES_CHUNK_STORE_READER_H_
 
#include <cstddef>
#include <cstdint>
#include <memory>
#include <optional>
 
#include <absl/status/status.h>
#include <absl/status/statusor.h>
#include <absl/time/time.h>
 
#include "a11/concurrency/future.h"
#include "a11/data/types.h"
#include "a11/stores/chunk_store.h"
 
namespace a11::stores {
 
struct ChunkStoreReaderOptions {
  bool ordered = true;
  bool pop_chunks = false;
  std::uint64_t num_chunks_to_buffer = 32;
  std::uint32_t offset = 0;
  std::optional<std::uint64_t> max_chunks_to_read = {};
  bool sticky_mimetype = false;
 
  absl::Status Validate() const;
};
 
class ChunkStoreReader {
 public:
  static absl::StatusOr<std::shared_ptr<ChunkStoreReader>> Create(
      std::shared_ptr<ChunkStore> store, ChunkStoreReaderOptions options = {});
 
  ~ChunkStoreReader() = default;
 
  void EnsureStarted();
 
  void Cancel();
 
  absl::Status GetStatus() const;
 
  [[nodiscard]] a11::Task Done() const;
 
  a11::Future<std::optional<data::NodeFragment>> Next(
      absl::Duration timeout = absl::InfiniteDuration());
 
  a11::Future<std::vector<std::optional<data::NodeFragment>>> NextMany(
      size_t limit, absl::Duration timeout = absl::InfiniteDuration());
 
  [[nodiscard]] std::shared_ptr<ChunkStore> store() const;
  [[nodiscard]] ChunkStoreReaderOptions options() const;
  [[nodiscard]] size_t buffer_size() const;
 
 private:
  struct State;
 
  explicit ChunkStoreReader(std::shared_ptr<State> state)
      : state_(std::move(state)) {}
 
  std::shared_ptr<State> state_;
};
 
}  // namespace a11::stores
 
#endif  // A11_STORES_CHUNK_STORE_READER_H_