packet_type.h | Explore in Territory

// 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_PACKET_TYPE_H_
#define MEDIAPIPE_FRAMEWORK_PACKET_TYPE_H_

#include <map>
#include <memory>
#include <set>
#include <string>
#include <typeinfo>
#include <vector>

#include "absl/base/macros.h"
#include "absl/log/absl_check.h"
#include "absl/log/absl_log.h"
#include "absl/status/status.h"
#include "absl/strings/str_split.h"
#include "absl/strings/string_view.h"
#include "absl/types/span.h"
#include "mediapipe/framework/collection.h"
#include "mediapipe/framework/deps/no_destructor.h"
#include "mediapipe/framework/packet.h"
#include "mediapipe/framework/packet_set.h"
#include "mediapipe/framework/port/status.h"
#include "mediapipe/framework/tool/type_util.h"
#include "mediapipe/framework/tool/validate_name.h"
#include "mediapipe/framework/type_map.h"

namespace mediapipe {

// Encapsulates the type and description of an input stream, output
// stream, or input side packet.  The type to expect is set with Set<type>()
// and a packet is validated with Validate().  The PacketType can be
// set to indicate the same type as some other PacketType.
class PacketType { … };

// An error handler class which allows a PacketTypeSet to return valid
// results while deferring errors.
//
// This class is thread compatible.
class PacketTypeSetErrorHandler { … };

// A collection of PacketTypes.  The types are either retrieved by index
// or by tag.  The calculator must set a type for every input stream and
// input side packet that it accepts and every output stream it produces.
// Every (non-const) function in this class always returns valid values
// that can be used directly without error checking.  If the types don't
// match what the user provided then an error will be triggered later
// (but the program will not crash).
//
// For example, a calculator can just call
//   inputs->Tag("VIDEO").Set<ImageFrame>("Annotated Video Frames.");
// Without checking that "VIDEO" is a valid tag.
//
// Similarly if the following is specified:
//   inputs->Index(0).Set<int>("Some Integer.");
//   inputs->Index(1).Set<std::string>("Some String.");
//   inputs->Index(2).Set<float>("Some Float.");
// then it is not necessary to check that NumEntries() == 3. An error
// is triggered if there aren't exactly 3 inputs or they don't have the
// proper types.
//
// For a const PacketTypeSet, invalid access is a fatal error.
//
// This class is thread compatible.
PacketTypeSet;

// Returns OK if the packets in the PacketSet are of the appropriate type.
// packet_type_set must be valid before this is called (but packet_set
// may be in any state).
absl::Status ValidatePacketSet(const PacketTypeSet& packet_type_set,
                               const PacketSet& packet_set);

// Validates that the PacketTypeSet was initialized properly.
// An error is returned if
// 1) Tag() or Index() is called with an invalid argument (however,
//    a valid PacketType is still returned by the function).
// 2) Any PacketType is not initialized.
absl::Status ValidatePacketTypeSet(const PacketTypeSet& packet_type_set);

// Templated function definitions.

template <typename T>
PacketType& PacketType::Set() { … }

template <typename... T>
PacketType& PacketType::SetOneOf() { … }

}  // namespace mediapipe

#endif  // MEDIAPIPE_FRAMEWORK_PACKET_TYPE_H_
chromium/third_party/mediapipe/src/mediapipe/framework/packet_type.h
