+
+ private static final class SshWriteAsyncHandler implements AutoCloseable {
+ public static final int MAX_PENDING_WRITES = 100;
+
+ private final ChannelOutboundHandler channelHandler;
+ private IoOutputStream asyncIn;
+
+ // Counter that holds the amount of pending write messages
+ // Pending write can occur in case remote window is full
+ // In such case, we need to wait for the pending write to finish
+ private int pendingWriteCounter;
+ // Last write future, that can be pending
+ private IoWriteFuture lastWriteFuture;
+
+ public SshWriteAsyncHandler(final ChannelOutboundHandler channelHandler, final IoOutputStream asyncIn) {
+ this.channelHandler = channelHandler;
+ this.asyncIn = asyncIn;
+ }
+
+ int c = 0;
+
+ public synchronized void write(final ChannelHandlerContext ctx, final Object msg, final ChannelPromise promise) {
+ try {
+ if(asyncIn == null || asyncIn.isClosed() || asyncIn.isClosing()) {
+ // If we are closed/closing, set immediate fail
+ promise.setFailure(new IllegalStateException("Channel closed"));
+ } else {
+ lastWriteFuture = asyncIn.write(toBuffer(msg));
+ lastWriteFuture.addListener(new SshFutureListener<IoWriteFuture>() {
+
+ @Override
+ public void operationComplete(final IoWriteFuture future) {
+ ((ByteBuf) msg).release();
+
+ // Notify success or failure
+ if (future.isWritten()) {
+ promise.setSuccess();
+ } else {
+ promise.setFailure(future.getException());
+ }
+
+ // Reset last pending future
+ synchronized (SshWriteAsyncHandler.this) {
+ lastWriteFuture = null;
+ }
+ }
+ });
+ }
+ } catch (final WritePendingException e) {
+ // Check limit for pending writes
+ pendingWriteCounter++;
+ if(pendingWriteCounter > MAX_PENDING_WRITES) {
+ promise.setFailure(e);
+ handlePendingFailed(ctx, new IllegalStateException("Too much pending writes(" + MAX_PENDING_WRITES + ") on channel: " + ctx.channel() +
+ ", remote window is not getting read or is too small"));
+ }
+
+ // We need to reset buffer read index, since we've already read it when we tried to write it the first time
+ ((ByteBuf) msg).resetReaderIndex();
+ logger.debug("Write pending to SSH remote on channel: {}, current pending count: {}", ctx.channel(), pendingWriteCounter);
+
+ // In case of pending, re-invoke write after pending is finished
+ Preconditions.checkNotNull(lastWriteFuture, "Write is pending, but there was no previous write attempt", e);
+ lastWriteFuture.addListener(new SshFutureListener<IoWriteFuture>() {
+ @Override
+ public void operationComplete(final IoWriteFuture future) {
+ // FIXME possible minor race condition, we cannot guarantee that this callback when pending is finished will be executed first
+ // External thread could trigger write on this instance while we are on this line
+ // Verify
+ if (future.isWritten()) {
+ synchronized (SshWriteAsyncHandler.this) {
+ // Pending done, decrease counter
+ pendingWriteCounter--;
+ write(ctx, msg, promise);
+ }
+ } else {
+ // Cannot reschedule pending, fail
+ handlePendingFailed(ctx, e);
+ }
+ }
+
+ });
+ }
+ }
+
+ private void handlePendingFailed(final ChannelHandlerContext ctx, final Exception e) {
+ logger.warn("Exception while writing to SSH remote on channel {}", ctx.channel(), e);
+ try {
+ channelHandler.disconnect(ctx, ctx.newPromise());
+ } catch (final Exception ex) {
+ // This should not happen
+ throw new IllegalStateException(ex);
+ }
+ }
+
+ @Override
+ public void close() {
+ asyncIn = null;
+ }
+
+ private Buffer toBuffer(final Object msg) {
+ // TODO Buffer vs ByteBuf translate, Can we handle that better ?
+ Preconditions.checkState(msg instanceof ByteBuf);
+ final ByteBuf byteBuf = (ByteBuf) msg;
+ final byte[] temp = new byte[byteBuf.readableBytes()];
+ byteBuf.readBytes(temp, 0, byteBuf.readableBytes());
+ return new Buffer(temp);
+ }
+
+ }