HTTP2Transport.h

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/*
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *     http://aws.amazon.com/apache2.0/
 *
 * or in the "license" file accompanying this file. This file 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 ALEXA_CLIENT_SDK_ACL_INCLUDE_ACL_TRANSPORT_HTTP2TRANSPORT_H_
#define ALEXA_CLIENT_SDK_ACL_INCLUDE_ACL_TRANSPORT_HTTP2TRANSPORT_H_

#include <atomic>
#include <chrono>
#include <deque>
#include <memory>
#include <mutex>
#include <string>
#include <thread>
#include <unordered_set>

#include <AVSCommon/AVS/Attachment/AttachmentManagerInterface.h>
#include <AVSCommon/SDKInterfaces/AuthDelegateInterface.h>
#include <AVSCommon/SDKInterfaces/EventTracerInterface.h>
#include <AVSCommon/SDKInterfaces/MessageSenderInterface.h>
#include <AVSCommon/Utils/HTTP2/HTTP2ConnectionInterface.h>
#include <AVSCommon/Utils/HTTP2/HTTP2ConnectionObserverInterface.h>
#include <AVSCommon/Utils/Metrics/MetricRecorderInterface.h>
#include <AVSCommon/Utils/Power/PowerResource.h>
#include <AVSCommon/Utils/Timing/DistantFuture.h>
#include <AVSCommon/Utils/Threading/ConditionVariableWrapper.h>

#include "ACL/Transport/MessageConsumerInterface.h"
#include "ACL/Transport/PingHandler.h"
#include "ACL/Transport/PostConnectFactoryInterface.h"
#include "ACL/Transport/PostConnectObserverInterface.h"
#include "ACL/Transport/TransportObserverInterface.h"
#include "ACL/Transport/SynchronizedMessageRequestQueue.h"

namespace alexaClientSDK {
namespace acl {

class HTTP2Transport
        : public std::enable_shared_from_this<HTTP2Transport>
        , public TransportInterface
        , public PostConnectObserverInterface
        , public avsCommon::sdkInterfaces::MessageSenderInterface
        , public avsCommon::sdkInterfaces::AuthObserverInterface
        , public avsCommon::utils::http2::HTTP2ConnectionObserverInterface
        , public ExchangeHandlerContextInterface {
public:
    /*
     *  Defines a set of HTTP2/2 connection settings.
     */
    struct Configuration {
        /*
         * Constructor. Initializes the configuration to default.
         */
        Configuration();

        std::chrono::seconds inactivityTimeout;
    };

    static std::shared_ptr<HTTP2Transport> create(
        std::shared_ptr<avsCommon::sdkInterfaces::AuthDelegateInterface> authDelegate,
        const std::string& avsGateway,
        std::shared_ptr<avsCommon::utils::http2::HTTP2ConnectionInterface> http2Connection,
        std::shared_ptr<MessageConsumerInterface> messageConsumer,
        std::shared_ptr<avsCommon::avs::attachment::AttachmentManagerInterface> attachmentManager,
        std::shared_ptr<TransportObserverInterface> transportObserver,
        std::shared_ptr<PostConnectFactoryInterface> postConnectFactory,
        std::shared_ptr<SynchronizedMessageRequestQueue> sharedRequestQueue,
        Configuration configuration = Configuration(),
        std::shared_ptr<avsCommon::utils::metrics::MetricRecorderInterface> metricRecorder = nullptr,
        std::shared_ptr<avsCommon::sdkInterfaces::EventTracerInterface> eventTracer = nullptr);

    void addObserver(std::shared_ptr<TransportObserverInterface> transportObserver);

    void removeObserver(std::shared_ptr<TransportObserverInterface> observer);

    std::shared_ptr<avsCommon::utils::http2::HTTP2ConnectionInterface> getHTTP2Connection();

    bool connect() override;
    void disconnect() override;
    bool isConnected() override;
    void onRequestEnqueued() override;
    void onWakeConnectionRetry() override;
    void onWakeVerifyConnectivity() override;

    void sendMessage(std::shared_ptr<avsCommon::avs::MessageRequest> request) override;

    void onPostConnected() override;
    void onUnRecoverablePostConnectFailure() override;

    void onAuthStateChange(
        avsCommon::sdkInterfaces::AuthObserverInterface::State newState,
        avsCommon::sdkInterfaces::AuthObserverInterface::Error error) override;

    void doShutdown() override;

    void onDownchannelConnected() override;
    void onDownchannelFinished() override;
    void onMessageRequestSent(const std::shared_ptr<avsCommon::avs::MessageRequest>& request) override;
    void onMessageRequestTimeout() override;
    void onMessageRequestAcknowledged(const std::shared_ptr<avsCommon::avs::MessageRequest>& request) override;
    void onMessageRequestFinished() override;
    void onPingRequestAcknowledged(bool success) override;
    void onPingTimeout() override;
    void onActivity() override;
    void onForbidden(const std::string& authToken = "") override;
    std::shared_ptr<avsCommon::utils::http2::HTTP2RequestInterface> createAndSendRequest(
        const avsCommon::utils::http2::HTTP2RequestConfig& cfg) override;
    std::string getAVSGateway() override;

    void onGoawayReceived() override;

private:
    enum class State {
        INIT,
        AUTHORIZING,
        CONNECTING,
        WAITING_TO_RETRY_CONNECTING,
        POST_CONNECTING,
        CONNECTED,
        SERVER_SIDE_DISCONNECT,
        DISCONNECTING,
        SHUTDOWN
    };

    // Friend to allow access to enum class State.
    friend std::ostream& operator<<(std::ostream& stream, HTTP2Transport::State state);

    HTTP2Transport(
        std::shared_ptr<avsCommon::sdkInterfaces::AuthDelegateInterface> authDelegate,
        const std::string& avsGateway,
        std::shared_ptr<avsCommon::utils::http2::HTTP2ConnectionInterface> http2Connection,
        std::shared_ptr<MessageConsumerInterface> messageConsumer,
        std::shared_ptr<avsCommon::avs::attachment::AttachmentManagerInterface> attachmentManager,
        std::shared_ptr<TransportObserverInterface> transportObserver,
        std::shared_ptr<PostConnectFactoryInterface> postConnectFactory,
        std::shared_ptr<SynchronizedMessageRequestQueue> sharedRequestQueue,
        Configuration configuration,
        std::shared_ptr<avsCommon::utils::metrics::MetricRecorderInterface> metricRecorder,
        std::shared_ptr<avsCommon::sdkInterfaces::EventTracerInterface> eventTracer);

    void mainLoop();

    State handleInit();

    State handleAuthorizing();

    State handleConnecting();

    State handleWaitingToRetryConnecting();

    State handlePostConnecting();

    State handleConnected();

    State handleServerSideDisconnect();

    State handleDisconnecting();

    State handleShutdown();

    State monitorSharedQueueWhileWaiting(
        State whileState,
        std::chrono::time_point<std::chrono::steady_clock> maxWakeTime = avsCommon::utils::timing::getDistantFuture());

    State sendMessagesAndPings(State whileState, MessageRequestQueueInterface& requestQueue);

    bool setState(
        State newState,
        avsCommon::sdkInterfaces::ConnectionStatusObserverInterface::ChangedReason changedReason);

    bool setStateLocked(
        State newState,
        avsCommon::sdkInterfaces::ConnectionStatusObserverInterface::ChangedReason reason);

    void notifyObserversOnConnected();

    void notifyObserversOnDisconnect(avsCommon::sdkInterfaces::ConnectionStatusObserverInterface::ChangedReason reason);

    void notifyObserversOnServerSideDisconnect();

    State getState();

    std::shared_ptr<avsCommon::utils::metrics::MetricRecorderInterface> m_metricRecorder;

    std::mutex m_mutex;

    avsCommon::utils::threading::ConditionVariableWrapper m_wakeEvent;

    State m_state;

    std::shared_ptr<avsCommon::sdkInterfaces::AuthDelegateInterface> m_authDelegate;

    std::string m_avsGateway;

    std::shared_ptr<avsCommon::utils::http2::HTTP2ConnectionInterface> m_http2Connection;

    std::shared_ptr<MessageConsumerInterface> m_messageConsumer;

    std::shared_ptr<avsCommon::avs::attachment::AttachmentManagerInterface> m_attachmentManager;

    std::shared_ptr<PostConnectFactoryInterface> m_postConnectFactory;

    std::shared_ptr<SynchronizedMessageRequestQueue> m_sharedRequestQueue;

    std::shared_ptr<avsCommon::sdkInterfaces::EventTracerInterface> m_eventTracer;

    std::mutex m_observerMutex;

    std::unordered_set<std::shared_ptr<TransportObserverInterface>> m_observers;

    std::thread m_thread;

    std::shared_ptr<PostConnectInterface> m_postConnect;

    MessageRequestQueue m_requestQueue;

    int m_connectRetryCount;

    int m_countOfUnfinishedMessageHandlers;

    std::shared_ptr<PingHandler> m_pingHandler;

    std::chrono::time_point<std::chrono::steady_clock> m_timeOfLastActivity;

    std::atomic<bool> m_postConnected;

    const Configuration m_configuration;

    avsCommon::sdkInterfaces::ConnectionStatusObserverInterface::ChangedReason m_disconnectReason;

    std::shared_ptr<avsCommon::utils::power::PowerResource> m_mainLoopPowerResource;

    std::shared_ptr<avsCommon::utils::power::PowerResource> m_requestActivityPowerResource;
};

}  // namespace acl
}  // namespace alexaClientSDK

#endif  // ALEXA_CLIENT_SDK_ACL_INCLUDE_ACL_TRANSPORT_HTTP2TRANSPORT_H_