Function parseChannelMessages

lib/internal/child_process/serialization.js:32–76

(channel, readData)

  },

  *parseChannelMessages(channel, readData) {
    if (readData.length === 0) return;

    if (channel[kMessageBufferSize] && channel[kMessageBuffer][0].length < 4) {
      // Message length split into two buffers, so let's concatenate it.
      channel[kMessageBuffer][0] = Buffer.concat([channel[kMessageBuffer][0], readData]);
    } else {
      ArrayPrototypePush(channel[kMessageBuffer], readData);
    }
    channel[kMessageBufferSize] += readData.length;

    // Index 0 should always be present because we just pushed data into it.
    let messageBufferHead = channel[kMessageBuffer][0];
    while (messageBufferHead.length >= 4) {
      // We call `readUInt32BE` manually here, because this is faster than first converting
      // it to a buffer and using `readUInt32BE` on that.
      const fullMessageSize = ((
        messageBufferHead[0] << 24 |
        messageBufferHead[1] << 16 |
        messageBufferHead[2] << 8 |
        messageBufferHead[3]
      ) >>> 0) + 4;

      if (channel[kMessageBufferSize] < fullMessageSize) break;

      const concatenatedBuffer = channel[kMessageBuffer].length === 1 ?
        channel[kMessageBuffer][0] :
        Buffer.concat(
          channel[kMessageBuffer],
          channel[kMessageBufferSize],
        );

      const serializedMessage =
        TypedArrayPrototypeSubarray(concatenatedBuffer, 4, fullMessageSize);

      messageBufferHead = TypedArrayPrototypeSubarray(concatenatedBuffer, fullMessageSize);
      channel[kMessageBufferSize] = messageBufferHead.length;
      channel[kMessageBuffer] =
        channel[kMessageBufferSize] !== 0 ? [messageBufferHead] : [];

      yield deserialize(serializedMessage);
    }

    channel.buffering = channel[kMessageBufferSize] > 0;
  },

  writeChannelMessage(channel, req, message, handle) {
    // Pass the stable Buffer constructor so the native codec can classify Node