demo version

demo/camera_client/dependencies/libvisiontransfer/visiontransfer/datachannelservicebase.h

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+/*******************************************************************************
+ * Copyright (c) 2021 Nerian Vision GmbH
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *******************************************************************************/
+
+#include <memory>
+#include <map>
+#include <set>
+#include <string>
+#include <vector>
+#include <algorithm>
+
+#ifdef _WIN32
+#include <winsock2.h>
+#else
+#include <arpa/inet.h>
+#endif
+
+#ifndef VISIONTRANSFER_DATACHANNELSERVICEBASE_H
+#define VISIONTRANSFER_DATACHANNELSERVICEBASE_H
+
+namespace visiontransfer {
+namespace internal {
+
+/*
+ * This is a header file for internal use, please use the wrappers from datachannelservice.h
+ */
+
+#pragma pack(push,1)
+/**
+ * \brief Transport-level DataChannel header
+ */
+struct DataChannelMessageHeader {
+    uint8_t channelID;
+    uint8_t channelType;
+    uint32_t payloadSize;
+};
+struct DataChannelMessage {
+    DataChannelMessageHeader header;
+    unsigned char* payload;
+};
+#pragma pack(pop)
+
+
+
+class DataChannelServiceBase;
+/**
+ * \brief Base class all data channel services derive from (once on the server side, once on the API side)
+ */
+class DataChannel {
+public:
+    /**
+     * \brief Known data channel service types, not all may be active on a specific device
+     */
+    struct Types {
+        enum DataChannelTypesEnum {
+            CONTROL             = 0x00,
+            BNO080              = 0x01,
+            UNDEFINED           = 0xff
+        };
+    };
+
+    typedef unsigned char Type;
+    typedef unsigned char ID;
+
+    inline DataChannel(): infoString("RESERVED") { }
+    inline virtual ~DataChannel() {}
+    inline ID getChannelID() const { return channelID; }
+    inline std::string getInfoString() const { return infoString; }
+    inline void setService(std::weak_ptr<DataChannelServiceBase> serv) { service = serv; }
+    inline void setChannelID(ID id) { channelID = id; }
+
+    virtual Type getChannelType() const = 0;
+    /// \brief Channel-dependent message handlers in respective channel implementations
+    virtual int handleMessage(DataChannelMessage& message, sockaddr_in* sender) = 0;
+    /// \brief When initialize() implementations return false, the service will be deactivated
+    virtual bool initialize() = 0;
+    /// \brief startService() implementations can start devices, launch an IO-blocked worker thread etc.
+    virtual int startService() = 0;
+    /** \brief A single processing iteration; should be short and must not block.
+     *  Actual frequency determined by the thread calling DataChannelServiceBase::process()
+     */
+    virtual bool process() { return true; }
+    virtual int stopService() = 0;
+protected:
+    std::string infoString;
+    int sendData(unsigned char* data, unsigned int dataSize, sockaddr_in* recipient=nullptr);
+private:
+    ID channelID;
+    std::weak_ptr<DataChannelServiceBase> service;
+};
+
+/**
+ * \brief API-level data channel info for advertisements and subscription accounting
+ */
+class DataChannelInfo {
+public:
+    inline DataChannelInfo(DataChannel::ID id, DataChannel::Type type, const std::string& info): channelID(id), channelType(type), infoString(info) { }
+    inline DataChannel::ID   getChannelID() const { return channelID; }
+    inline DataChannel::Type getChannelType() const { return channelType; }
+    inline std::string     getInfoString() const { return infoString; }
+private:
+    DataChannel::ID channelID;
+    DataChannel::Type channelType;
+    std::string infoString;
+};
+
+
+
+/**
+ * \brief Base class for the data service (background sending and receiving, dispatching to channels)
+ */
+class DataChannelServiceBase: public std::enable_shared_from_this<DataChannelServiceBase> {
+public:
+    DataChannelServiceBase();
+    ~DataChannelServiceBase();
+    void process();
+    DataChannel::ID registerChannel(std::shared_ptr<DataChannel> channel);
+    virtual int sendDataInternal(unsigned char* compiledMessage, unsigned int messageSize, sockaddr_in* recipient);
+    int sendDataIsolatedPacket(DataChannel::ID id, DataChannel::Type type, unsigned char* data, unsigned int dataSize, sockaddr_in* recipient);
+    virtual int handleChannel0Message(DataChannelMessage& message, sockaddr_in* sender) = 0;
+protected:
+    std::map<DataChannel::ID, std::shared_ptr<DataChannel> > channels;
+#ifdef _WIN32
+    SOCKET dataChannelSocket;
+#else
+    int dataChannelSocket;
+#endif
+    DataChannelMessage message;
+};
+
+
+}} // namespaces
+
+#endif
+