chromium/third_party/mediapipe/src/mediapipe/framework/input_stream_handler.h

// Copyright 2019 The MediaPipe 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 MEDIAPIPE_FRAMEWORK_INPUT_STREAM_HANDLER_H_
#define MEDIAPIPE_FRAMEWORK_INPUT_STREAM_HANDLER_H_

#include <atomic>
#include <functional>
#include <list>
#include <memory>
#include <string>
#include <utility>
#include <vector>

// TODO: Move protos in another CL after the C++ code migration.
#include "mediapipe/framework/calculator_context.h"
#include "mediapipe/framework/calculator_context_manager.h"
#include "mediapipe/framework/collection.h"
#include "mediapipe/framework/collection_item_id.h"
#include "mediapipe/framework/deps/registration.h"
#include "mediapipe/framework/input_stream_manager.h"
#include "mediapipe/framework/input_stream_shard.h"
#include "mediapipe/framework/mediapipe_options.pb.h"
#include "mediapipe/framework/packet.h"
#include "mediapipe/framework/packet_set.h"
#include "mediapipe/framework/packet_type.h"
#include "mediapipe/framework/port/status.h"
#include "mediapipe/framework/tool/tag_map.h"

namespace mediapipe {

// Indicates the operation the node is ready for.
enum class NodeReadiness { … };

// Abstract base class for input stream handlers.
//
// The input stream handler is invoked every time a Packet is enqueued or the
// next timestamp bound is set in any of the input streams and actually decides
// whether a calculator node's Process() should be called. The input stream
// handler owns and manages the InputStreamManager objects. The operations
// performed by OutputStreamHandler on an InputStreamManager object need to go
// through its input stream handler.
//
// Derived classes are required to implement the following member functions:
//
//   NodeReadiness GetNodeReadiness(Timestamp* min_stream_timestamp);
//   void FillInputSet(Timestamp input_timestamp,
//                     InputStreamShardSet* input_set);
//
class InputStreamHandler { … };

using InputStreamHandlerRegistry = GlobalFactoryRegistry<
    std::unique_ptr<InputStreamHandler>, std::shared_ptr<tool::TagMap>,
    CalculatorContextManager*, const MediaPipeOptions&, bool>;

}  // namespace mediapipe

// Macro for registering the input stream handler.
#define REGISTER_INPUT_STREAM_HANDLER(name) …

#endif  // MEDIAPIPE_FRAMEWORK_INPUT_STREAM_HANDLER_H_