Tomcat原理系列之七:详解socket如何封装成request(下)

public SocketBufferHandler(int readBufferSize, int writeBufferSize,
            boolean direct) {
        this.direct = direct;
        if (direct) {
            readBuffer = ByteBuffer.allocateDirect(readBufferSize);//默认8k
            writeBuffer = ByteBuffer.allocateDirect(writeBufferSize);
        } else {
            readBuffer = ByteBuffer.allocate(readBufferSize);
            writeBuffer = ByteBuffer.allocate(writeBufferSize);
        }
    }

try {
            if (socketWrapper == null) {
                return false;
            }
            SocketProcessorBase<S> sc = processorCache.pop();
            if (sc == null) {
                sc = createSocketProcessor(socketWrapper, event);
            } else {
                sc.reset(socketWrapper, event);
            }
            Executor executor = getExecutor();//线程池
            if (dispatch && executor != null) {
                executor.execute(sc);
            } else {
                sc.run();
            }
        } catch (RejectedExecutionException ree) {

// Setting up the I/O
        setSocketWrapper(socketWrapper);
        inputBuffer.init(socketWrapper);
        outputBuffer.init(socketWrapper);

void init(SocketWrapperBase<?> socketWrapper) {
        wrapper = socketWrapper;
        wrapper.setAppReadBufHandler(this);
        int bufLength = headerBufferSize +
                wrapper.getSocketBufferHandler().getReadBuffer().capacity();
        if (byteBuffer == null || byteBuffer.capacity() < bufLength) {
            byteBuffer = ByteBuffer.allocate(bufLength);
            byteBuffer.position(0).limit(0);
        }
    }

// Read new bytes if needed
if (byteBuffer.position() >= byteBuffer.limit()) {//判断
   if (keptAlive) {
       // Haven't read any request data yet so use the keep-alive
       // timeout.
       wrapper.setReadTimeout(wrapper.getEndpoint().getKeepAliveTimeout());
   }
   if (!fill(false)) {//填充
       // A read is pending, so no longer in initial state
       parsingRequestLinePhase = 1;
       return false;
   }
   // At least one byte of the request has been received.
   // Switch to the socket timeout.
   wrapper.setReadTimeout(wrapper.getEndpoint().getConnectionTimeout());
}

@Override
        public int read(boolean block, ByteBuffer to) throws IOException {
          //先从tomcat 底层socket buffer 缓冲区读，如果buffer缓冲区还有未读的buffer，则不需要到OS底层读缓冲区读
            int nRead = populateReadBuffer(to);
            if (nRead > 0) {
                return nRead;
                /*
                 * Since more bytes may have arrived since the buffer was last
                 * filled, it is an option at this point to perform a
                 * non-blocking read. However correctly handling the case if
                 * that read returns end of stream adds complexity. Therefore,
                 * at the moment, the preference is for simplicity.
                 */
            }
            // The socket read buffer capacity is socket.appReadBufSize
            int limit = socketBufferHandler.getReadBuffer().capacity();
            if (to.remaining() >= limit) {
                to.limit(to.position() + limit);
                nRead = fillReadBuffer(block, to);
                if (log.isDebugEnabled()) {
                    log.debug("Socket: [" + this + "], Read direct from socket: [" + nRead + "]");
                }
                updateLastRead();
            } else {
                // Fill the read buffer as best we can.
                nRead = fillReadBuffer(block);
                if (log.isDebugEnabled()) {
                    log.debug("Socket: [" + this + "], Read into buffer: [" + nRead + "]");
                }
                updateLastRead();
                // Fill as much of the remaining byte array as possible with the
                // data that was just read
                if (nRead > 0) {
                    nRead = populateReadBuffer(to);
                }
            }
            return nRead;
        }

if (parsingRequestLinePhase == 2) {
            //
            // Reading the method name
            // Method name is a token
            //
            boolean space = false;
            while (!space) {
                // Read new bytes if needed
                if (byteBuffer.position() >= byteBuffer.limit()) {
                    if (!fill(false)) // request line parsing
                        return false;
                }
                // Spec says method name is a token followed by a single SP but
                // also be tolerant of multiple SP and/or HT.
                int pos = byteBuffer.position();
                byte chr = byteBuffer.get();
                if (chr == Constants.SP || chr == Constants.HT) {
                    space = true;
                    //请求的方法（get/post）
                    request.method().setBytes(byteBuffer.array(), parsingRequestLineStart,
                            pos - parsingRequestLineStart);
                } else if (!HttpParser.isToken(chr)) {
                    byteBuffer.position(byteBuffer.position() - 1);
                    throw new IllegalArgumentException(sm.getString("iib.invalidmethod"));
                }
            }

// Calling the container
 connector.getService().getContainer().getPipeline().getFirst().invoke(
                        request, response);