| /* |
| * Copyright 2016, Google Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package io.grpc.internal; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.base.Preconditions.checkState; |
| |
| import io.grpc.CallCredentials.MetadataApplier; |
| import io.grpc.CallOptions; |
| import io.grpc.Context; |
| import io.grpc.Metadata; |
| import io.grpc.MethodDescriptor; |
| import io.grpc.Status; |
| |
| import javax.annotation.Nullable; |
| import javax.annotation.concurrent.GuardedBy; |
| |
| final class MetadataApplierImpl implements MetadataApplier { |
| private final ClientTransport transport; |
| private final MethodDescriptor<?, ?> method; |
| private final Metadata origHeaders; |
| private final CallOptions callOptions; |
| private final Context ctx; |
| private final StatsTraceContext statsTraceCtx; |
| |
| private final Object lock = new Object(); |
| |
| // null if neither apply() or returnStream() are called. |
| // Needs this lock because apply() and returnStream() may race |
| @GuardedBy("lock") |
| @Nullable |
| private ClientStream returnedStream; |
| |
| boolean finalized; |
| |
| // not null if returnStream() was called before apply() |
| DelayedStream delayedStream; |
| |
| MetadataApplierImpl(ClientTransport transport, MethodDescriptor<?, ?> method, |
| Metadata origHeaders, CallOptions callOptions, StatsTraceContext statsTraceCtx) { |
| this.transport = transport; |
| this.method = method; |
| this.origHeaders = origHeaders; |
| this.callOptions = callOptions; |
| this.ctx = Context.current(); |
| this.statsTraceCtx = statsTraceCtx; |
| } |
| |
| @Override |
| public void apply(Metadata headers) { |
| checkState(!finalized, "apply() or fail() already called"); |
| checkNotNull(headers, "headers"); |
| origHeaders.merge(headers); |
| ClientStream realStream; |
| Context origCtx = ctx.attach(); |
| try { |
| realStream = transport.newStream(method, origHeaders, callOptions, statsTraceCtx); |
| } finally { |
| ctx.detach(origCtx); |
| } |
| finalizeWith(realStream); |
| } |
| |
| @Override |
| public void fail(Status status) { |
| checkArgument(!status.isOk(), "Cannot fail with OK status"); |
| checkState(!finalized, "apply() or fail() already called"); |
| finalizeWith(new FailingClientStream(status)); |
| } |
| |
| private void finalizeWith(ClientStream stream) { |
| checkState(!finalized, "already finalized"); |
| finalized = true; |
| synchronized (lock) { |
| if (returnedStream == null) { |
| // Fast path: returnStream() hasn't been called, the call will use the |
| // real stream directly. |
| returnedStream = stream; |
| return; |
| } |
| } |
| // returnStream() has been called before me, thus delayedStream must have been |
| // created. |
| checkState(delayedStream != null, "delayedStream is null"); |
| delayedStream.setStream(stream); |
| } |
| |
| /** |
| * Return a stream on which the RPC will run on. |
| */ |
| ClientStream returnStream() { |
| synchronized (lock) { |
| if (returnedStream == null) { |
| // apply() has not been called, needs to buffer the requests. |
| delayedStream = new DelayedStream(); |
| return returnedStream = delayedStream; |
| } else { |
| return returnedStream; |
| } |
| } |
| } |
| } |