15-7 mediasoup下channel创建的详细过程

channel 是用于nodejs 与C++交互的，也就是nodejs 可以通过channel 想c++发送指令，同理C++也可以通过该channel 向nodejs 发响应消息。

medisoup/lib/Worker.js

通过socket就可以跟C++那一端通信了。
new的Channel来自Channel.js。

C++部分
mediasoup\worker\src\handles\UnixStreamSocket.cpp
UnixStreamSocket构造函数

inline static void onRead(uv_stream_t* handle, ssize_t nread, const uv_buf_t* buf)
{
    auto* socket = static_cast<UnixStreamSocket*>(handle->data);
    if (socket)
        socket->OnUvRead(nread, buf);
}
UnixStreamSocket::UnixStreamSocket(int fd, size_t bufferSize, UnixStreamSocket::Role role)
  : bufferSize(bufferSize), role(role)
{
    MS_TRACE_STD();
    int err;
    this->uvHandle       = new uv_pipe_t;
    this->uvHandle->data = static_cast<void*>(this);
    err = uv_pipe_init(DepLibUV::GetLoop(), this->uvHandle, 0);
    if (err != 0)
    {
        delete this->uvHandle;
        this->uvHandle = nullptr;
        MS_THROW_ERROR_STD("uv_pipe_init() failed: %s", uv_strerror(err));
    }
    err = uv_pipe_open(this->uvHandle, fd);
    if (err != 0)
    {
        uv_close(reinterpret_cast<uv_handle_t*>(this->uvHandle), static_cast<uv_close_cb>(onClose));
        MS_THROW_ERROR_STD("uv_pipe_open() failed: %s", uv_strerror(err));
    }
    if (this->role == UnixStreamSocket::Role::CONSUMER)
    {
        // Start reading.
        err = uv_read_start(
          reinterpret_cast<uv_stream_t*>(this->uvHandle),
          static_cast<uv_alloc_cb>(onAlloc),
           //数据来时会调用该回调
          static_cast<uv_read_cb>(onRead));
        if (err != 0)
        {
            uv_close(reinterpret_cast<uv_handle_t*>(this->uvHandle), static_cast<uv_close_cb>(onClose));
            MS_THROW_ERROR_STD("uv_read_start() failed: %s", uv_strerror(err));
        }
    }
    // NOTE: Don't allocate the buffer here. Instead wait for the first uv_alloc_cb().
}

读取数据后，将数据转为json格式
inline void UnixStreamSocket::OnUvRead(ssize_t nread, const uv_buf_t /buf*/)

Worker::OnChannelRequest

https://www.cnblogs.com/ssyfj/p/14851442.html