{"action":"created","comment":{"url":"https://api.github.com/repos/grpc/grpc-java/pulls/comments/26951500","id":26951500,"diff_hunk":"@@ -0,0 +1,313 @@\n+/*\n+ * Copyright 2015, Google Inc. All rights reserved.\n+ *\n+ * Redistribution and use in source and binary forms, with or without\n+ * modification, are permitted provided that the following conditions are\n+ * met:\n+ *\n+ *    * Redistributions of source code must retain the above copyright\n+ * notice, this list of conditions and the following disclaimer.\n+ *    * Redistributions in binary form must reproduce the above\n+ * copyright notice, this list of conditions and the following disclaimer\n+ * in the documentation and/or other materials provided with the\n+ * distribution.\n+ *\n+ *    * Neither the name of Google Inc. nor the names of its\n+ * contributors may be used to endorse or promote products derived from\n+ * this software without specific prior written permission.\n+ *\n+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS\n+ * \"AS IS\" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT\n+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR\n+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT\n+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,\n+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT\n+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,\n+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY\n+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT\n+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE\n+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.\n+ */\n+\n+package io.grpc.transport.netty;\n+\n+import static io.netty.handler.codec.http2.Http2Error.PROTOCOL_ERROR;\n+import static io.netty.handler.codec.http2.Http2Exception.connectionError;\n+import static java.lang.Math.min;\n+\n+import io.netty.buffer.ByteBuf;\n+import io.netty.channel.ChannelFuture;\n+import io.netty.channel.ChannelHandlerContext;\n+import io.netty.channel.ChannelPromise;\n+import io.netty.handler.codec.http2.DefaultHttp2ConnectionEncoder;\n+import io.netty.handler.codec.http2.Http2CodecUtil;\n+import io.netty.handler.codec.http2.Http2Connection;\n+import io.netty.handler.codec.http2.Http2ConnectionAdapter;\n+import io.netty.handler.codec.http2.Http2ConnectionEncoder;\n+import io.netty.handler.codec.http2.Http2FrameWriter;\n+import io.netty.handler.codec.http2.Http2Headers;\n+import io.netty.handler.codec.http2.Http2LifecycleManager;\n+import io.netty.handler.codec.http2.Http2Stream;\n+\n+import java.util.ArrayDeque;\n+import java.util.Map;\n+import java.util.Queue;\n+import java.util.TreeMap;\n+\n+/**\n+ * Implementation of a {@link Http2ConnectionEncoder} that is identical to\n+ * {@link DefaultHttp2ConnectionEncoder}, but for when the maximum number of concurrent streams\n+ * is hit. When this limit is hit, instead of rejecting any new streams this implementation buffers\n+ * newly created streams and their corresponding frames. Once an active stream gets closed or the\n+ * maximum number of concurrent streams is increased, the encoder will automatically try to empty\n+ * its buffer and create as many new streams as possible. This implementation makes the buffering\n+ * mostly transparent and can be used as a drop in replacement for\n+ * {@link DefaultHttp2ConnectionEncoder}.\n+ */\n+public class BufferingHttp2ConnectionEncoder extends DefaultHttp2ConnectionEncoder {\n+\n+  // Buffer for any streams and corresponding frames that could not be created\n+  // due to the maximum concurrent stream limit being hit.\n+  private TreeMap<Integer, PendingStream> pendingStreams = new TreeMap<Integer, PendingStream>();\n+  // Smallest stream id whose corresponding frames do not get buffered.\n+  int largestCreatedStreamId;\n+\n+  protected BufferingHttp2ConnectionEncoder(Builder builder) {\n+    super(builder);\n+    connection().addListener(new Http2ConnectionAdapter() {\n+      @Override\n+      public void goingAway() {\n+        cancelPendingStreams();\n+      }\n+\n+      @Override\n+      public void streamInactive(Http2Stream stream) {\n+        createNextPendingStream();\n+      }\n+    });\n+  }\n+\n+  /**\n+   * Builder for new instances of {@link BufferingHttp2ConnectionEncoder}.\n+   */\n+  public static class Builder extends DefaultHttp2ConnectionEncoder.Builder {\n+    @Override\n+    public Builder connection(Http2Connection connection) {\n+      this.connection = connection;\n+      return this;\n+    }\n+\n+    @Override\n+    public Builder lifecycleManager(Http2LifecycleManager lifecycleManager) {\n+      this.lifecycleManager = lifecycleManager;\n+      return this;\n+    }\n+\n+    @Override\n+    public Http2LifecycleManager lifecycleManager() {\n+      return lifecycleManager;\n+    }\n+\n+    @Override\n+    public Builder frameWriter(Http2FrameWriter frameWriter) {\n+      this.frameWriter = frameWriter;\n+      return this;\n+    }\n+\n+    @Override\n+    public Http2ConnectionEncoder build() {\n+      return new BufferingHttp2ConnectionEncoder(this);\n+    }\n+  }\n+\n+  public static Builder newBuilder() {\n+    return new Builder();\n+  }\n+\n+  @Override\n+  public ChannelFuture writeHeaders(ChannelHandlerContext ctx, int streamId, Http2Headers headers,\n+                                    int padding, boolean endStream, ChannelPromise promise) {\n+    return writeHeaders(ctx, streamId, headers, 0, Http2CodecUtil.DEFAULT_PRIORITY_WEIGHT, false,\n+                        padding, endStream, promise);\n+  }\n+\n+  @Override\n+  public ChannelFuture writeHeaders(ChannelHandlerContext ctx, int streamId, Http2Headers headers,\n+                                    int streamDependency, short weight, boolean exclusive,\n+                                    int padding, boolean endOfStream, ChannelPromise promise) {\n+    if (existingStream(streamId)) {\n+      return super.writeHeaders(ctx, streamId, headers, streamDependency, weight, exclusive,\n+                                padding, endOfStream, promise);\n+    }\n+    if (connection().local().acceptingNewStreams()) {\n+      assert streamId > largestCreatedStreamId;\n+      largestCreatedStreamId = streamId;\n+      return super.writeHeaders(ctx, streamId, headers, streamDependency, weight, exclusive,\n+                                padding, endOfStream, promise);\n+    }\n+    if (connection().isGoAway()) {\n+      promise.setFailure(\n+              connectionError(PROTOCOL_ERROR, \"Sending headers after connection going away.\"));\n+      return promise;\n+    }\n+    PendingStream pendingStream = pendingStreams.get(streamId);\n+    if (pendingStream == null) {\n+      pendingStream = new PendingStream(ctx, streamId);\n+      pendingStreams.put(streamId, pendingStream);\n+    }\n+    pendingStream.frames.add(new HeadersFrame(headers, streamDependency, weight, exclusive,\n+                             padding, endOfStream, promise));\n+    return promise;\n+  }\n+\n+  @Override\n+  public ChannelFuture writeRstStream(ChannelHandlerContext ctx, int streamId, long errorCode,","path":"netty/src/main/java/io/grpc/transport/netty/BufferingHttp2ConnectionEncoder.java","position":164,"original_position":164,"commit_id":"4abb50c9435c48cf3855fc8ba0afb79a3f02a346","original_commit_id":"4abb50c9435c48cf3855fc8ba0afb79a3f02a346","user":{"login":"nmittler","id":6493296,"avatar_url":"https://avatars.githubusercontent.com/u/6493296?v=3","gravatar_id":"","url":"https://api.github.com/users/nmittler","html_url":"https://github.com/nmittler","followers_url":"https://api.github.com/users/nmittler/followers","following_url":"https://api.github.com/users/nmittler/following{/other_user}","gists_url":"https://api.github.com/users/nmittler/gists{/gist_id}","starred_url":"https://api.github.com/users/nmittler/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/nmittler/subscriptions","organizations_url":"https://api.github.com/users/nmittler/orgs","repos_url":"https://api.github.com/users/nmittler/repos","events_url":"https://api.github.com/users/nmittler/events{/privacy}","received_events_url":"https://api.github.com/users/nmittler/received_events","type":"User","site_admin":false},"body":"Could we just use the super class version always?  Won't sending RST_STREAM automatically trigger cancellation of the pending stream via the `Connection.Listener` callback?","created_at":"2015-03-23T16:14:26Z","updated_at":"2015-03-23T16:14:26Z","html_url":"https://github.com/grpc/grpc-java/pull/225#discussion_r26951500","pull_request_url":"https://api.github.com/repos/grpc/grpc-java/pulls/225","_links":{"self":{"href":"https://api.github.com/repos/grpc/grpc-java/pulls/comments/26951500"},"html":{"href":"https://github.com/grpc/grpc-java/pull/225#discussion_r26951500"},"pull_request":{"href":"https://api.github.com/repos/grpc/grpc-java/pulls/225"}}},"pull_request":{"url":"https://api.github.com/repos/grpc/grpc-java/pulls/225","id":31643251,"html_url":"https://github.com/grpc/grpc-java/pull/225","diff_url":"https://github.com/grpc/grpc-java/pull/225.diff","patch_url":"https://github.com/grpc/grpc-java/pull/225.patch","issue_url":"https://api.github.com/repos/grpc/grpc-java/issues/225","number":225,"state":"open","locked":false,"title":"Remove blocking on netty client stream creation.","user":{"login":"buchgr","id":1388179,"avatar_url":"https://avatars.githubusercontent.com/u/1388179?v=3","gravatar_id":"","url":"https://api.github.com/users/buchgr","html_url":"https://github.com/buchgr","followers_url":"https://api.github.com/users/buchgr/followers","following_url":"https://api.github.com/users/buchgr/following{/other_user}","gists_url":"https://api.github.com/users/buchgr/gists{/gist_id}","starred_url":"https://api.github.com/users/buchgr/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/buchgr/subscriptions","organizations_url":"https://api.github.com/users/buchgr/orgs","repos_url":"https://api.github.com/users/buchgr/repos","events_url":"https://api.github.com/users/buchgr/events{/privacy}","received_events_url":"https://api.github.com/users/buchgr/received_events","type":"User","site_admin":false},"body":"See #118 .","created_at":"2015-03-20T19:12:58Z","updated_at":"2015-03-23T16:14:26Z","closed_at":null,"merged_at":null,"merge_commit_sha":"07cda225f3a7162f4df09d5eee654d57197e0ac5","assignee":null,"milestone":null,"commits_url":"https://api.github.com/repos/grpc/grpc-java/pulls/225/commits","review_comments_url":"https://api.github.com/repos/grpc/grpc-java/pulls/225/comments","review_comment_url":"https://api.github.com/repos/grpc/grpc-java/pulls/comments{/number}","comments_url":"https://api.github.com/repos/grpc/grpc-java/issues/225/comments","statuses_url":"https://api.github.com/repos/grpc/grpc-java/statuses/4abb50c9435c48cf3855fc8ba0afb79a3f02a346","head":{"label":"buchgr:maxconcurrent","ref":"maxconcurrent","sha":"4abb50c9435c48cf3855fc8ba0afb79a3f02a346","user":{"login":"buchgr","id":1388179,"avatar_url":"https://avatars.githubusercontent.com/u/1388179?v=3","gravatar_id":"","url":"https://api.github.com/users/buchgr","html_url":"https://github.com/buchgr","followers_url":"https://api.github.com/users/buchgr/followers","following_url":"https://api.github.com/users/buchgr/following{/other_user}","gists_url":"https://api.github.com/users/buchgr/gists{/gist_id}","starred_url":"https://api.github.com/users/buchgr/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/buchgr/subscriptions","organizations_url":"https://api.github.com/users/buchgr/orgs","repos_url":"https://api.github.com/users/buchgr/repos","events_url":"https://api.github.com/users/buchgr/events{/privacy}","received_events_url":"https://api.github.com/users/buchgr/received_events","type":"User","site_admin":false},"repo":{"id":31381511,"name":"grpc-java","full_name":"buchgr/grpc-java","owner":{"login":"buchgr","id":1388179,"avatar_url":"https://avatars.githubusercontent.com/u/1388179?v=3","gravatar_id":"","url":"https://api.github.com/users/buchgr","html_url":"https://github.com/buchgr","followers_url":"https://api.github.com/users/buchgr/followers","following_url":"https://api.github.com/users/buchgr/following{/other_user}","gists_url":"https://api.github.com/users/buchgr/gists{/gist_id}","starred_url":"https://api.github.com/users/buchgr/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/buchgr/subscriptions","organizations_url":"https://api.github.com/users/buchgr/orgs","repos_url":"https://api.github.com/users/buchgr/repos","events_url":"https://api.github.com/users/buchgr/events{/privacy}","received_events_url":"https://api.github.com/users/buchgr/received_events","type":"User","site_admin":false},"private":false,"html_url":"https://github.com/buchgr/grpc-java","description":"The Java gRPC implementation. 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