Initial implementation of RequestPriority-based HTTP/2 dependencies.

net/spdy/spdy_session.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_SPDY_SPDY_SESSION_H_
 #define NET_SPDY_SPDY_SESSION_H_
 
 #include <deque>
 #include <map>
 #include <set>
@@ skipping 498 matching lines @@
   // https://http2.github.io/http2-spec/#TLSUsage mandates minimum security
   // standards for TLS.
   bool HasAcceptableTransportSecurity() const;
 
   // Must be used only by |pool_|.
   base::WeakPtr<SpdySession> GetWeakPtr();
 
   // HigherLayeredPool implementation:
   bool CloseOneIdleConnection() override;
 
+  // Set whether priority->dependency conversion is enabled
+  // by default for all future SpdySessions.
+  static void SetPriorityDependencyDefaultForTesting(bool enable);

[Bence, 2015/11/11 18:47:15]

I don't like the idea of having a global variable for this, but I see that there
is no easy way around it.

I don't like the idea of making this method public, and if every test file
already had a peer class, I would propose to friend those peer classes here and
make this method private, but they don't, and it would be unreasonable to create
them just for this.

Maybe "ForTesting" in the method name is enough to deter developers from calling
it in non-test code.

[Randy Smith (Not in Mondays), 2015/11/11 23:25:59]

Agreed.
I'm not sure what you mean by peer class?  I added a mess of "friends" and
shifted around some anonymous namespaces, and got this method private; does that
do what you wanted?

+
  private:
   friend class base::RefCounted<SpdySession>;
   friend class SpdyStreamRequest;
   friend class SpdySessionTest;
 
   // Allow tests to access our innards for testing purposes.
   FRIEND_TEST_ALL_PREFIXES(SpdySessionTest, ClientPing);
   FRIEND_TEST_ALL_PREFIXES(SpdySessionTest, FailedPing);
   FRIEND_TEST_ALL_PREFIXES(SpdySessionTest, GetActivePushStream);
   FRIEND_TEST_ALL_PREFIXES(SpdySessionTest, DeleteExpiredPushStreams);
@@ skipping 468 matching lines @@
   // the server to start pushing the stream]) or there are still network events
   // incoming even though the consumer has already gone away (cancellation).
   //
   // |active_streams_| owns all its SpdyStream objects.
   //
   // TODO(willchan): Perhaps we should separate out cancelled streams and move
   // them into a separate ActiveStreamMap, and not deliver network events to
   // them?
   ActiveStreamMap active_streams_;
 
+  // Per-priority map from stream id to all active streams.  This map will
+  // contain the same set of streams as |active_streams_|.  It is used for
+  // setting dependencies to match incoming requests RequestPriority.
+  //
+  // |active_streams_by_priority_| does *not* own its SpdyStream objects.
+  std::map<SpdyStreamId, SpdyStream*>
+      active_streams_by_priority_[NUM_PRIORITIES];
+
   // (Bijective) map from the URL to the ID of the streams that have
   // already started to be pushed by the server, but do not have
   // consumers yet. Contains a subset of |active_streams_|.
   PushedStreamMap unclaimed_pushed_streams_;
 
   // Set of all created streams but that have not yet sent any frames.
   //
   // |created_streams_| owns all its SpdyStream objects.
   CreatedStreamSet created_streams_;
 
@@ skipping 158 matching lines @@
   // to build a new connection, and see if that completes before we (finally)
   // get a PING response (http://crbug.com/127812).
   base::TimeDelta hung_interval_;
 
   // This SPDY proxy is allowed to push resources from origins that are
   // different from those of their associated streams.
   HostPortPair trusted_spdy_proxy_;
 
   TimeFunc time_func_;
 
+  // Should priority-based depencency information be sent in stream header

[Bence, 2015/11/11 18:47:15]

s/depencency/dependency/

[Randy Smith (Not in Mondays), 2015/11/11 23:25:59]

Done.

+  // frames.
+  bool send_priority_dependency_;
+
   // Used for posting asynchronous IO tasks.  We use this even though
   // SpdySession is refcounted because we don't need to keep the SpdySession
   // alive if the last reference is within a RunnableMethod.  Just revoke the
   // method.
   base::WeakPtrFactory<SpdySession> weak_factory_;
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_SPDY_SESSION_H_