LibCurlHttpContentFetcher.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_AVSCOMMON_UTILS_INCLUDE_AVSCOMMON_UTILS_LIBCURLUTILS_LIBCURLHTTPCONTENTFETCHER_H_
#define ALEXA_CLIENT_SDK_AVSCOMMON_UTILS_INCLUDE_AVSCOMMON_UTILS_LIBCURLUTILS_LIBCURLHTTPCONTENTFETCHER_H_

#include <atomic>
#include <future>
#include <string>
#include <thread>

#include <AVSCommon/SDKInterfaces/HTTPContentFetcherInterface.h>
#include <AVSCommon/Utils/LibcurlUtils/CurlEasyHandleWrapper.h>
#include <AVSCommon/Utils/LibcurlUtils/LibcurlSetCurlOptionsCallbackInterface.h>

namespace alexaClientSDK {
namespace avsCommon {
namespace utils {
namespace libcurlUtils {

class LibCurlHttpContentFetcher : public avsCommon::sdkInterfaces::HTTPContentFetcherInterface {
public:
    explicit LibCurlHttpContentFetcher(
        const std::string& url,
        const std::shared_ptr<LibcurlSetCurlOptionsCallbackInterface>& setCurlOptionsCallback = nullptr);

    State getState() override;
    std::string getUrl() const override;
    std::string getEffectiveUrl() const override;
    Header getHeader(std::atomic<bool>* shouldShutdown) override;
    bool getBody(std::shared_ptr<avsCommon::avs::attachment::AttachmentWriter> writer) override;
    void shutdown() override;

    std::unique_ptr<avsCommon::utils::HTTPContent> getContent(
        FetchOptions option,
        std::unique_ptr<avsCommon::avs::attachment::AttachmentWriter> writer = nullptr,
        const std::vector<std::string>& customHeaders = std::vector<std::string>()) override;

    /*
     * Destructor.
     */
    ~LibCurlHttpContentFetcher() override;

private:
    static size_t headerCallback(char* data, size_t size, size_t nmemb, void* userData);

    static size_t bodyCallback(char* data, size_t size, size_t nmemb, void* userData);

    static size_t noopCallback(char* data, size_t size, size_t nmemb, void* userData);

    State m_state;

    curl_slist* getCustomHeaderList(const std::vector<std::string>& customHeaders);

    const std::string m_url;

    mutable std::mutex m_effectiveUrlMutex;

    std::string m_effectiveUrl;

    CurlEasyHandleWrapper m_curlWrapper;

    std::promise<bool> m_headerPromise;

    std::shared_future<bool> m_headerFuture;

    HTTPContentFetcherInterface::Header m_header;

    std::shared_ptr<avsCommon::avs::attachment::AttachmentWriter> m_streamWriter;

    ssize_t m_currentContentReceivedLength;

    ssize_t m_totalContentReceivedLength;

    std::atomic<bool> m_done;

    std::atomic<bool> m_isShutdown;

    std::thread m_thread;

    std::atomic<bool> m_hasObjectBeenUsed;

    std::mutex m_stateMutex;

    std::mutex m_getBodyMutex;

    void reportInvalidStateTransitionAttempt(State currentState, State newState);

    void stateTransition(State newState, bool value);

    bool waitingForBodyRequest();

    void updateEffectiveURL();
};

}  // namespace libcurlUtils
}  // namespace utils
}  // namespace avsCommon
}  // namespace alexaClientSDK

#endif  // ALEXA_CLIENT_SDK_AVSCOMMON_UTILS_INCLUDE_AVSCOMMON_UTILS_LIBCURLUTILS_LIBCURLHTTPCONTENTFETCHER_H_