QUIC - add instrumentation to HPACK.

net/quic/quic_headers_stream.h

 // Copyright 2013 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_QUIC_QUIC_HEADERS_STREAM_H_
 #define NET_QUIC_QUIC_HEADERS_STREAM_H_
 
 #include <stddef.h>
 
 #include <memory>
 
 #include "base/macros.h"
 #include "net/base/net_export.h"
 #include "net/quic/quic_header_list.h"
 #include "net/quic/quic_protocol.h"
 #include "net/quic/reliable_quic_stream.h"
 #include "net/spdy/spdy_framer.h"
 
 namespace net {
 
 class QuicSpdySession;
 
 // Headers in QUIC are sent as HTTP/2 HEADERS or PUSH_PROMISE frames
 // over a reserved reliable stream with the id 3.  Each endpoint
 // (client and server) will allocate an instance of QuicHeadersStream
 // to send and receive headers.
 class NET_EXPORT_PRIVATE QuicHeadersStream : public ReliableQuicStream {
  public:
+  class NET_EXPORT_PRIVATE HpackDebugVisitor {
+   public:
+    HpackDebugVisitor();
+
+    virtual ~HpackDebugVisitor();
+
+    // For each HPACK indexed representation processed, |elapsed| is
+    // the time since the corresponding entry was added to the dynamic
+    // table.
+    virtual void OnUseEntry(QuicTime::Delta elapsed) = 0;
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(HpackDebugVisitor);
+  };
+
   explicit QuicHeadersStream(QuicSpdySession* session);
   ~QuicHeadersStream() override;
 
   // Writes |headers| for |stream_id| in an HTTP/2 HEADERS frame to the peer.
   // If |fin| is true, the fin flag will be set on the HEADERS frame.  Returns
   // the size, in bytes, of the resulting HEADERS frame.
   virtual size_t WriteHeaders(QuicStreamId stream_id,
                               const SpdyHeaderBlock& headers,
                               bool fin,
                               SpdyPriority priority,
@@ skipping 10 matching lines @@
   // ReliableQuicStream implementation
   void OnDataAvailable() override;
 
   bool supports_push_promise() { return supports_push_promise_; }
 
   // Experimental: force HPACK to use static table and huffman coding
   // only.  Part of exploring improvements related to headers stream
   // induced HOL blocking in QUIC.
   void DisableHpackDynamicTable();
 
+  // Optional, enables instrumentation related to go/quic-hpack.
+  void SetHpackEncoderDebugVisitor(std::unique_ptr<HpackDebugVisitor> visitor);
+  void SetHpackDecoderDebugVisitor(std::unique_ptr<HpackDebugVisitor> visitor);
+
  private:
   class SpdyFramerVisitor;
 
   // The following methods are called by the SimpleVisitor.
 
   // Called when a HEADERS frame has been received.
   void OnHeaders(SpdyStreamId stream_id,
                  bool has_priority,
                  SpdyPriority priority,
                  bool fin);
@@ skipping 49 matching lines @@
 
   // Either empty, or contains the complete list of headers.
   QuicHeaderList header_list_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicHeadersStream);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_HEADERS_STREAM_H_