Function setupChannel

lib/internal/child_process.js:619–994

(target, channel, serializationMode)

let serialization;
function setupChannel(target, channel, serializationMode) {
  const control = new Control(channel);
  target.channel = control;
  target[kChannelHandle] = channel;

  target._handleQueue = null;
  target._pendingMessage = null;

  if (serialization === undefined)
    serialization = require('internal/child_process/serialization');
  const {
    initMessageChannel,
    parseChannelMessages,
    writeChannelMessage,
  } = serialization[serializationMode];

  let pendingHandle = null;
  initMessageChannel(channel);
  channel.pendingHandle = null;
  channel.onread = function(arrayBuffer) {
    const recvHandle = channel.pendingHandle;
    channel.pendingHandle = null;
    if (arrayBuffer) {
      const nread = streamBaseState[kReadBytesOrError];
      const offset = streamBaseState[kArrayBufferOffset];
      const pool = new Uint8Array(arrayBuffer, offset, nread);
      if (recvHandle)
        pendingHandle = recvHandle;

      for (const message of parseChannelMessages(channel, pool)) {
        // There will be at most one NODE_HANDLE message in every chunk we
        // read because SCM_RIGHTS messages don't get coalesced. Make sure
        // that we deliver the handle with the right message however.
        if (isInternal(message)) {
          if (message.cmd === 'NODE_HANDLE') {
            handleMessage(message, pendingHandle, true);
            pendingHandle = null;
          } else {
            handleMessage(message, undefined, true);
          }
        } else {
          handleMessage(message, undefined, false);
        }
      }
    } else {
      this.buffering = false;
      target.disconnect();
      channel.onread = nop;
      channel.close();
      target.channel = null;
      maybeClose(target);
    }
  };

  // Object where socket lists will live
  channel.sockets = { got: {}, send: {} };

  // Handlers will go through this