Class StandardStreamInputBuffer

java/org/apache/coyote/http2/Stream.java:1216–1542

    class StandardStreamInputBuffer extends StreamInputBuffer {

        private final Lock readStateLock = new ReentrantLock();
        /*
         * Two buffers are required to avoid various multi-threading issues. These issues arise from the fact that the
         * Stream (or the Request/Response) used by the application is processed in one thread but the connection is
         * processed in another. Therefore it is possible that a request body frame could be received before the
         * application is ready to read it. If it isn't buffered, processing of the connection (and hence all streams)
         * would block until the application read the data. Hence the incoming data has to be buffered. If only one
         * buffer was used then it could become corrupted if the connection thread is trying to add to it at the same
         * time as the application is read it. While it should be possible to avoid this corruption by careful use of
         * the buffer it would still require the same copies as using two buffers and the behaviour would be less clear.
         *
         * The buffers are created lazily because they quickly add up to a lot of memory and most requests do not have
         * bodies.
         */
        // This buffer is used to populate the ByteChunk passed in to the read
        // method
        private byte[] outBuffer;
        // This buffer is the destination for incoming data. It is normally is
        // 'write mode'.
        private volatile ByteBuffer inBuffer;
        private volatile boolean readInterest;
        // If readInterest is true, data must be available to read no later than this time.
        private volatile long readTimeoutExpiry;
        private volatile boolean closed;
        private volatile boolean resetReceived;

        @Override
        public final int doRead(ApplicationBufferHandler applicationBufferHandler) throws IOException {

            ensureBuffersExist();

            int written;

            // It is still possible that the stream has been closed and inBuffer
            // set to null between the call to ensureBuffersExist() above and
            // the sync below. The checks just before and just inside the sync
            // ensure we don't get any NPEs reported.
            ByteBuffer tmpInBuffer = inBuffer;
            if (tmpInBuffer == null) {
                return -1;
            }
            // Ensure that only one thread accesses inBuffer at a time
            synchronized (tmpInBuffer) {
                if (inBuffer == null) {
                    return -1;
                }
                boolean canRead = false;
                while (inBuffer.position() == 0 && (canRead = isActive() && !isInputFinished())) {
                    // Need to block until some data is written
                    try {
                        if (log.isTraceEnabled()) {
                            log.trace(sm.getString("stream.inputBuffer.empty"));
                        }

                        long readTimeout = handler.getProtocol().getStreamReadTimeout();
                        if (readTimeout < 0) {