/*
 * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package jdk.internal.net.http;

import java.io.EOFException;
import java.lang.System.Logger.Level;
import java.nio.ByteBuffer;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.Executor;
import java.util.concurrent.Flow;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.Consumer;
import java.util.function.Function;
import java.net.http.HttpHeaders;
import java.net.http.HttpResponse;
import jdk.internal.net.http.ResponseContent.BodyParser;
import jdk.internal.net.http.ResponseContent.UnknownLengthBodyParser;
import jdk.internal.net.http.common.Log;
import jdk.internal.net.http.common.Logger;
import jdk.internal.net.http.common.MinimalFuture;
import jdk.internal.net.http.common.Utils;
import static java.net.http.HttpClient.Version.HTTP_1_1;
import static java.net.http.HttpResponse.BodySubscribers.discarding;
import static jdk.internal.net.http.common.Utils.wrapWithExtraDetail;
import static jdk.internal.net.http.RedirectFilter.HTTP_NOT_MODIFIED;

Handles a HTTP/1.1 response (headers + body).
There can be more than one of these per Http exchange.
/**
 * Handles a HTTP/1.1 response (headers + body).
 * There can be more than one of these per Http exchange.
 */
class Http1Response<T> {

    private volatile ResponseContent content;
    private final HttpRequestImpl request;
    private Response response;
    private final HttpConnection connection;
    private HttpHeaders headers;
    private int responseCode;
    private final Http1Exchange<T> exchange;
    private boolean return2Cache; // return connection to cache when finished
    private final HeadersReader headersReader; // used to read the headers
    private final BodyReader bodyReader; // used to read the body
    private final Http1AsyncReceiver asyncReceiver;
    private volatile EOFException eof;
    private volatile BodyParser bodyParser;
    // max number of bytes of (fixed length) body to ignore on redirect
    private final static int MAX_IGNORE = 1024;

    // Revisit: can we get rid of this?
    static enum State {INITIAL, READING_HEADERS, READING_BODY, DONE}
    private volatile State readProgress = State.INITIAL;

    final Logger debug = Utils.getDebugLogger(this::dbgString, Utils.DEBUG);
    final static AtomicLong responseCount = new AtomicLong();
    final long id = responseCount.incrementAndGet();
    private Http1HeaderParser hd;

    Http1Response(HttpConnection conn,
                  Http1Exchange<T> exchange,
                  Http1AsyncReceiver asyncReceiver) {
        this.readProgress = State.INITIAL;
        this.request = exchange.request();
        this.exchange = exchange;
        this.connection = conn;
        this.asyncReceiver = asyncReceiver;
        headersReader = new HeadersReader(this::advance);
        bodyReader = new BodyReader(this::advance);

        hd = new Http1HeaderParser();
        readProgress = State.READING_HEADERS;
        headersReader.start(hd);
        asyncReceiver.subscribe(headersReader);
    }

    String dbgTag;
    private String dbgString() {
        String dbg = dbgTag;
        if (dbg == null) {
            String cdbg = connection.dbgTag;
            if (cdbg != null) {
                dbgTag = dbg = "Http1Response(id=" + id + ", " + cdbg + ")";
            } else {
                dbg = "Http1Response(id=" + id + ")";
            }
        }
        return dbg;
    }

    // The ClientRefCountTracker is used to track the state
    // of a pending operation. Altough there usually is a single
    // point where the operation starts, it may terminate at
    // different places.
    private final class ClientRefCountTracker {
        final HttpClientImpl client = connection.client();
        // state & 0x01 != 0 => acquire called
        // state & 0x02 != 0 => tryRelease called
        byte state;

        public synchronized void acquire() {
            if (state == 0) {
                // increment the reference count on the HttpClientImpl
                // to prevent the SelectorManager thread from exiting
                // until our operation is complete.
                if (debug.on())
                    debug.log("Operation started: incrementing ref count for %s", client);
                client.reference();
                state = 0x01;
            } else {
                if (debug.on())
                    debug.log("Operation ref count for %s is already %s",
                              client, ((state & 0x2) == 0x2) ? "released." : "incremented!" );
                assert (state & 0x01) == 0 : "reference count already incremented";
            }
        }

        public synchronized void tryRelease() {
            if (state == 0x01) {
                // decrement the reference count on the HttpClientImpl
                // to allow the SelectorManager thread to exit if no
                // other operation is pending and the facade is no
                // longer referenced.
                if (debug.on())
                    debug.log("Operation finished: decrementing ref count for %s", client);
                client.unreference();
            } else if (state == 0) {
                if (debug.on())
                    debug.log("Operation finished: releasing ref count for %s", client);
            } else if ((state & 0x02) == 0x02) {
                if (debug.on())
                    debug.log("ref count for %s already released", client);
            }
            state |= 0x02;
        }
    }

    private volatile boolean firstTimeAround = true;

    public CompletableFuture<Response> readHeadersAsync(Executor executor) {
        if (debug.on())
            debug.log("Reading Headers: (remaining: "
                      + asyncReceiver.remaining() +") "  + readProgress);

        if (firstTimeAround) {
            if (debug.on()) debug.log("First time around");
            firstTimeAround = false;
        } else {
            // with expect continue we will resume reading headers + body.
            asyncReceiver.unsubscribe(bodyReader);
            bodyReader.reset();

            hd = new Http1HeaderParser();
            readProgress = State.READING_HEADERS;
            headersReader.reset();
            headersReader.start(hd);
            asyncReceiver.subscribe(headersReader);
        }

        CompletableFuture<State> cf = headersReader.completion();
        assert cf != null : "parsing not started";
        if (debug.on()) {
            debug.log("headersReader is %s",
                    cf == null ? "not yet started"
                            : cf.isDone() ? "already completed"
                            : "not yet completed");
        }

        Function<State, Response> lambda = (State completed) -> {
                assert completed == State.READING_HEADERS;
                if (debug.on())
                    debug.log("Reading Headers: creating Response object;"
                              + " state is now " + readProgress);
                asyncReceiver.unsubscribe(headersReader);
                responseCode = hd.responseCode();
                headers = hd.headers();

                response = new Response(request,
                                        exchange.getExchange(),
                                        headers,
                                        connection,
                                        responseCode,
                                        HTTP_1_1);

                if (Log.headers()) {
                    StringBuilder sb = new StringBuilder("RESPONSE HEADERS:\n");
                    Log.dumpHeaders(sb, "    ", headers);
                    Log.logHeaders(sb.toString());
                }

                return response;
            };

        if (executor != null) {
            return cf.thenApplyAsync(lambda, executor);
        } else {
            return cf.thenApply(lambda);
        }
    }

    private boolean finished;

    synchronized void completed() {
        finished = true;
    }

    synchronized boolean finished() {
        return finished;
    }

    
Return known fixed content length or -1 if chunked, or -2 if no content-length
information in which case, connection termination delimits the response body
/**
     * Return known fixed content length or -1 if chunked, or -2 if no content-length
     * information in which case, connection termination delimits the response body
     */
    long fixupContentLen(long clen) {
        if (request.method().equalsIgnoreCase("HEAD") || responseCode == HTTP_NOT_MODIFIED) {
            return 0L;
        }
        if (clen == -1L) {
            if (headers.firstValue("Transfer-encoding").orElse("")
                       .equalsIgnoreCase("chunked")) {
                return -1L;
            }
            if (responseCode == 101) {
                // this is a h2c or websocket upgrade, contentlength must be zero
                return 0L;
            }
            return -2L;
        }
        return clen;
    }

    
Read up to MAX_IGNORE bytes discarding
/**
     * Read up to MAX_IGNORE bytes discarding
     */
    public CompletableFuture<Void> ignoreBody(Executor executor) {
        int clen = (int)headers.firstValueAsLong("Content-Length").orElse(-1);
        if (clen == -1 || clen > MAX_IGNORE) {
            connection.close();
            return MinimalFuture.completedFuture(null); // not treating as error
        } else {
            return readBody(discarding(), true, executor);
        }
    }

    // Used for those response codes that have no body associated
    public void nullBody(HttpResponse<T> resp, Throwable t) {
        if (t != null) connection.close();
        else {
            return2Cache = !request.isWebSocket();
            onFinished();
        }
    }

    static final Flow.Subscription NOP = new Flow.Subscription() {
        @Override
        public void request(long n) { }
        public void cancel() { }
    };

    
The Http1AsyncReceiver ensures that all calls to
the subscriber, including onSubscribe, occur sequentially.
There could however be some race conditions that could happen
in case of unexpected errors thrown at unexpected places, which
may cause onError to be called multiple times.
The Http1BodySubscriber will ensure that the user subscriber
is actually completed only once - and only after it is
subscribed.
Type parameters:
<U> – The type of response./**
     * The Http1AsyncReceiver ensures that all calls to
     * the subscriber, including onSubscribe, occur sequentially.
     * There could however be some race conditions that could happen
     * in case of unexpected errors thrown at unexpected places, which
     * may cause onError to be called multiple times.
     * The Http1BodySubscriber will ensure that the user subscriber
     * is actually completed only once - and only after it is
     * subscribed.
     * @param <U> The type of response.
     */
    final static class Http1BodySubscriber<U> implements HttpResponse.BodySubscriber<U> {
        final HttpResponse.BodySubscriber<U> userSubscriber;
        final AtomicBoolean completed = new AtomicBoolean();
        volatile Throwable withError;
        volatile boolean subscribed;
        Http1BodySubscriber(HttpResponse.BodySubscriber<U> userSubscriber) {
            this.userSubscriber = userSubscriber;
        }

        // propagate the error to the user subscriber, even if not
        // subscribed yet.
        private void propagateError(Throwable t) {
            assert t != null;
            try {
                // if unsubscribed at this point, it will not
                // get subscribed later - so do it now and
                // propagate the error
                if (subscribed == false) {
                    subscribed = true;
                    userSubscriber.onSubscribe(NOP);
                }
            } finally  {
                // if onError throws then there is nothing to do
                // here: let the caller deal with it by logging
                // and closing the connection.
                userSubscriber.onError(t);
            }
        }

        // complete the subscriber, either normally or exceptionally
        // ensure that the subscriber is completed only once.
        private void complete(Throwable t) {
            if (completed.compareAndSet(false, true)) {
                t  = withError = Utils.getCompletionCause(t);
                if (t == null) {
                    assert subscribed;
                    try {
                        userSubscriber.onComplete();
                    } catch (Throwable x) {
                        // Simply propagate the error by calling
                        // onError on the user subscriber, and let the
                        // connection be reused since we should have received
                        // and parsed all the bytes when we reach here.
                        // If onError throws in turn, then we will simply
                        // let that new exception flow up to the caller
                        // and let it deal with it.
                        // (i.e: log and close the connection)
                        // Note that rethrowing here could introduce a
                        // race that might cause the next send() operation to
                        // fail as the connection has already been put back
                        // into the cache when we reach here.
                        propagateError(t = withError = Utils.getCompletionCause(x));
                    }
                } else {
                    propagateError(t);
                }
            }
        }

        @Override
        public CompletionStage<U> getBody() {
            return userSubscriber.getBody();
        }
        @Override
        public void onSubscribe(Flow.Subscription subscription) {
            if (!subscribed) {
                subscribed = true;
                userSubscriber.onSubscribe(subscription);
            } else {
                // could be already subscribed and completed
                // if an unexpected error occurred before the actual
                // subscription - though that's not supposed
                // happen.
                assert completed.get();
            }
        }
        @Override
        public void onNext(List<ByteBuffer> item) {
            assert !completed.get();
            userSubscriber.onNext(item);
        }
        @Override
        public void onError(Throwable throwable) {
            complete(throwable);
        }
        @Override
        public void onComplete() {
            complete(null);
        }
    }

    public <U> CompletableFuture<U> readBody(HttpResponse.BodySubscriber<U> p,
                                         boolean return2Cache,
                                         Executor executor) {
        this.return2Cache = return2Cache;
        final Http1BodySubscriber<U> subscriber = new Http1BodySubscriber<>(p);

        final CompletableFuture<U> cf = new MinimalFuture<>();

        long clen0 = headers.firstValueAsLong("Content-Length").orElse(-1L);
        final long clen = fixupContentLen(clen0);

        // expect-continue reads headers and body twice.
        // if we reach here, we must reset the headersReader state.
        asyncReceiver.unsubscribe(headersReader);
        headersReader.reset();
        ClientRefCountTracker refCountTracker = new ClientRefCountTracker();

        // We need to keep hold on the client facade until the
        // tracker has been incremented.
        connection.client().reference();
        executor.execute(() -> {
            try {
                content = new ResponseContent(
                        connection, clen, headers, subscriber,
                        this::onFinished
                );
                if (cf.isCompletedExceptionally()) {
                    // if an error occurs during subscription
                    connection.close();
                    return;
                }
                // increment the reference count on the HttpClientImpl
                // to prevent the SelectorManager thread from exiting until
                // the body is fully read.
                refCountTracker.acquire();
                bodyParser = content.getBodyParser(
                    (t) -> {
                        try {
                            if (t != null) {
                                try {
                                    subscriber.onError(t);
                                } finally {
                                    cf.completeExceptionally(t);
                                }
                            }
                        } finally {
                            bodyReader.onComplete(t);
                            if (t != null) {
                                connection.close();
                            }
                        }
                    });
                bodyReader.start(bodyParser);
                CompletableFuture<State> bodyReaderCF = bodyReader.completion();
                asyncReceiver.subscribe(bodyReader);
                assert bodyReaderCF != null : "parsing not started";
                // Make sure to keep a reference to asyncReceiver from
                // within this
                CompletableFuture<?> trailingOp = bodyReaderCF.whenComplete((s,t) ->  {
                    t = Utils.getCompletionCause(t);
                    try {
                        if (t == null) {
                            if (debug.on()) debug.log("Finished reading body: " + s);
                            assert s == State.READING_BODY;
                        }
                        if (t != null) {
                            subscriber.onError(t);
                            cf.completeExceptionally(t);
                        }
                    } catch (Throwable x) {
                        // not supposed to happen
                        asyncReceiver.onReadError(x);
                    } finally {
                        // we're done: release the ref count for
                        // the current operation.
                        refCountTracker.tryRelease();
                    }
                });
                connection.addTrailingOperation(trailingOp);
            } catch (Throwable t) {
               if (debug.on()) debug.log("Failed reading body: " + t);
                try {
                    subscriber.onError(t);
                    cf.completeExceptionally(t);
                } finally {
                    asyncReceiver.onReadError(t);
                }
            } finally {
                connection.client().unreference();
            }
        });
        try {
            p.getBody().whenComplete((U u, Throwable t) -> {
                if (t == null)
                    cf.complete(u);
                else
                    cf.completeExceptionally(t);
            });
        } catch (Throwable t) {
            cf.completeExceptionally(t);
            asyncReceiver.setRetryOnError(false);
            asyncReceiver.onReadError(t);
        }

        return cf.whenComplete((s,t) -> {
            if (t != null) {
                // If an exception occurred, release the
                // ref count for the current operation, as
                // it may never be triggered otherwise
                // (BodySubscriber ofInputStream)
                // If there was no exception then the
                // ref count will be/have been released when
                // the last byte of the response is/was received
                refCountTracker.tryRelease();
            }
        });
    }


    private void onFinished() {
        asyncReceiver.clear();
        if (return2Cache) {
            Log.logTrace("Attempting to return connection to the pool: {0}", connection);
            // TODO: need to do something here?
            // connection.setAsyncCallbacks(null, null, null);

            // don't return the connection to the cache if EOF happened.
            if (debug.on())
                debug.log(connection.getConnectionFlow() + ": return to HTTP/1.1 pool");
            connection.closeOrReturnToCache(eof == null ? headers : null);
        }
    }

    HttpHeaders responseHeaders() {
        return headers;
    }

    int responseCode() {
        return responseCode;
    }

// ================ Support for plugging into Http1Receiver   =================
// ============================================================================

    // Callback: Error receiver: Consumer of Throwable.
    void onReadError(Throwable t) {
        Log.logError(t);
        Receiver<?> receiver = receiver(readProgress);
        if (t instanceof EOFException) {
            debug.log(Level.DEBUG, "onReadError: received EOF");
            eof = (EOFException) t;
        }
        CompletableFuture<?> cf = receiver == null ? null : receiver.completion();
        debug.log(Level.DEBUG, () -> "onReadError: cf is "
                + (cf == null  ? "null"
                : (cf.isDone() ? "already completed"
                               : "not yet completed")));
        if (cf != null) {
            cf.completeExceptionally(t);
        } else {
            debug.log(Level.DEBUG, "onReadError", t);
        }
        debug.log(Level.DEBUG, () -> "closing connection: cause is " + t);
        connection.close();
    }

    // ========================================================================

    private State advance(State previous) {
        assert readProgress == previous;
        switch(previous) {
            case READING_HEADERS:
                asyncReceiver.unsubscribe(headersReader);
                return readProgress = State.READING_BODY;
            case READING_BODY:
                asyncReceiver.unsubscribe(bodyReader);
                return readProgress = State.DONE;
            default:
                throw new InternalError("can't advance from " + previous);
        }
    }

    Receiver<?> receiver(State state) {
        switch(state) {
            case READING_HEADERS: return headersReader;
            case READING_BODY: return bodyReader;
            default: return null;
        }

    }

    static abstract class Receiver<T>
            implements Http1AsyncReceiver.Http1AsyncDelegate {
        abstract void start(T parser);
        abstract CompletableFuture<State> completion();
        // accepts a buffer from upstream.
        // this should be implemented as a simple call to
        // accept(ref, parser, cf)
        public abstract boolean tryAsyncReceive(ByteBuffer buffer);
        public abstract void onReadError(Throwable t);
        // handle a byte buffer received from upstream.
        // this method should set the value of Http1Response.buffer
        // to ref.get() before beginning parsing.
        abstract void handle(ByteBuffer buf, T parser,
                             CompletableFuture<State> cf);
        // resets this objects state so that it can be reused later on
        // typically puts the reference to parser and completion to null
        abstract void reset();

        // accepts a byte buffer received from upstream
        // returns true if the buffer is fully parsed and more data can
        // be accepted, false otherwise.
        final boolean accept(ByteBuffer buf, T parser,
                CompletableFuture<State> cf) {
            if (cf == null || parser == null || cf.isDone()) return false;
            handle(buf, parser, cf);
            return !cf.isDone();
        }
        public abstract void onSubscribe(AbstractSubscription s);
        public abstract AbstractSubscription subscription();

    }

    // Invoked with each new ByteBuffer when reading headers...
    final class HeadersReader extends Receiver<Http1HeaderParser> {
        final Consumer<State> onComplete;
        volatile Http1HeaderParser parser;
        volatile CompletableFuture<State> cf;
        volatile long count; // bytes parsed (for debug)
        volatile AbstractSubscription subscription;

        HeadersReader(Consumer<State> onComplete) {
            this.onComplete = onComplete;
        }

        @Override
        public AbstractSubscription subscription() {
            return subscription;
        }

        @Override
        public void onSubscribe(AbstractSubscription s) {
            this.subscription = s;
            s.request(1);
        }

        @Override
        void reset() {
            cf = null;
            parser = null;
            count = 0;
            subscription = null;
        }

        // Revisit: do we need to support restarting?
        @Override
        final void start(Http1HeaderParser hp) {
            count = 0;
            cf = new MinimalFuture<>();
            parser = hp;
        }

        @Override
        CompletableFuture<State> completion() {
            return cf;
        }

        @Override
        public final boolean tryAsyncReceive(ByteBuffer ref) {
            boolean hasDemand = subscription.demand().tryDecrement();
            assert hasDemand;
            boolean needsMore = accept(ref, parser, cf);
            if (needsMore) subscription.request(1);
            return needsMore;
        }

        @Override
        public final void onReadError(Throwable t) {
            t = wrapWithExtraDetail(t, parser::currentStateMessage);
            Http1Response.this.onReadError(t);
        }

        @Override
        final void handle(ByteBuffer b,
                          Http1HeaderParser parser,
                          CompletableFuture<State> cf) {
            assert cf != null : "parsing not started";
            assert parser != null : "no parser";
            try {
                count += b.remaining();
                if (debug.on())
                    debug.log("Sending " + b.remaining() + "/" + b.capacity()
                              + " bytes to header parser");
                if (parser.parse(b)) {
                    count -= b.remaining();
                    if (debug.on())
                        debug.log("Parsing headers completed. bytes=" + count);
                    onComplete.accept(State.READING_HEADERS);
                    cf.complete(State.READING_HEADERS);
                }
            } catch (Throwable t) {
                if (debug.on())
                    debug.log("Header parser failed to handle buffer: " + t);
                cf.completeExceptionally(t);
            }
        }

        @Override
        public void close(Throwable error) {
            // if there's no error nothing to do: the cf should/will
            // be completed.
            if (error != null) {
                CompletableFuture<State> cf = this.cf;
                if (cf != null) {
                    if (debug.on())
                        debug.log("close: completing header parser CF with " + error);
                    cf.completeExceptionally(error);
                }
            }
        }
    }

    // Invoked with each new ByteBuffer when reading bodies...
    final class BodyReader extends Receiver<BodyParser> {
        final Consumer<State> onComplete;
        volatile BodyParser parser;
        volatile CompletableFuture<State> cf;
        volatile AbstractSubscription subscription;
        BodyReader(Consumer<State> onComplete) {
            this.onComplete = onComplete;
        }

        @Override
        void reset() {
            parser = null;
            cf = null;
            subscription = null;
        }

        // Revisit: do we need to support restarting?
        @Override
        final void start(BodyParser parser) {
            cf = new MinimalFuture<>();
            this.parser = parser;
        }

        @Override
        CompletableFuture<State> completion() {
            return cf;
        }

        @Override
        public final boolean tryAsyncReceive(ByteBuffer b) {
            return accept(b, parser, cf);
        }

        @Override
        public final void onReadError(Throwable t) {
            if (t instanceof EOFException && bodyParser != null &&
                    bodyParser instanceof UnknownLengthBodyParser) {
                ((UnknownLengthBodyParser)bodyParser).complete();
                return;
            }
            t = wrapWithExtraDetail(t, parser::currentStateMessage);
            Http1Response.this.onReadError(t);
        }

        @Override
        public AbstractSubscription subscription() {
            return subscription;
        }

        @Override
        public void onSubscribe(AbstractSubscription s) {
            this.subscription = s;
            try {
                parser.onSubscribe(s);
            } catch (Throwable t) {
                cf.completeExceptionally(t);
                throw t;
            }
        }

        @Override
        final void handle(ByteBuffer b,
                          BodyParser parser,
                          CompletableFuture<State> cf) {
            assert cf != null : "parsing not started";
            assert parser != null : "no parser";
            try {
                if (debug.on())
                    debug.log("Sending " + b.remaining() + "/" + b.capacity()
                              + " bytes to body parser");
                parser.accept(b);
            } catch (Throwable t) {
                if (debug.on())
                    debug.log("Body parser failed to handle buffer: " + t);
                if (!cf.isDone()) {
                    cf.completeExceptionally(t);
                }
            }
        }

        final void onComplete(Throwable closedExceptionally) {
            if (cf.isDone()) return;
            if (closedExceptionally != null) {
                cf.completeExceptionally(closedExceptionally);
            } else {
                onComplete.accept(State.READING_BODY);
                cf.complete(State.READING_BODY);
            }
        }

        @Override
        public final void close(Throwable error) {
            CompletableFuture<State> cf = this.cf;
            if (cf != null && !cf.isDone()) {
                // we want to make sure dependent actions are triggered
                // in order to make sure the client reference count
                // is decremented
                if (error != null) {
                    if (debug.on())
                        debug.log("close: completing body parser CF with " + error);
                    cf.completeExceptionally(error);
                } else {
                    if (debug.on())
                        debug.log("close: completing body parser CF");
                    cf.complete(State.READING_BODY);
                }
            }
        }

        @Override
        public String toString() {
            return super.toString() + "/parser=" + String.valueOf(parser);
        }
    }
}