Add a new priority level, THROTTLED, below IDLE.

net/spdy/spdy_http_utils.cc

 // 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.
 
 #include "net/spdy/spdy_http_utils.h"
 
 #include <string>
 
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
@@ skipping 155 matching lines @@
   (*headers)[status_key] = std::string(after_version + 1, after_status);
 
   size_t iter = 0;
   std::string raw_name, value;
   while (response_headers.EnumerateHeaderLines(&iter, &raw_name, &value)) {
     std::string name = base::ToLowerASCII(raw_name);
     AddSpdyHeader(name, value, headers);
   }
 }
 
-static_assert(HIGHEST - LOWEST < 4 && HIGHEST - MINIMUM_PRIORITY < 5,
+static_assert(HIGHEST - LOWEST < 4 && HIGHEST - MINIMUM_PRIORITY < 6,
               "request priority incompatible with spdy");
 
 SpdyPriority ConvertRequestPriorityToSpdyPriority(

[mmenke, 2016/05/09 19:25:42]

Need to have the QUIC/SPDY teams weigh in on changing this.

[Randy Smith (Not in Mondays), 2016/05/11 21:30:25]

Ryan, are you willing to play a SPDY expert on TV, since Bence's out?

     const RequestPriority priority,
     SpdyMajorVersion protocol_version) {
   DCHECK_GE(priority, MINIMUM_PRIORITY);
   DCHECK_LE(priority, MAXIMUM_PRIORITY);
   return static_cast<SpdyPriority>(MAXIMUM_PRIORITY - priority);
 }
 
 NET_EXPORT_PRIVATE RequestPriority ConvertSpdyPriorityToRequestPriority(
     SpdyPriority priority,
     SpdyMajorVersion protocol_version) {
   // Handle invalid values gracefully.
-  // Note that SpdyPriority is not an enum, hence the magic constants.
-  return (priority >= 5) ?
-      IDLE : static_cast<RequestPriority>(4 - priority);
+  return (priority > (MAXIMUM_PRIORITY - MINIMUM_PRIORITY))

[mmenke, 2016/05/09 19:25:42]

This maps IDLE priority to 4, THROTTLED to 5, and THROTTLED+1 to 4?  Why is this
different from the QUIC version?

[Randy Smith (Not in Mondays), 2016/05/11 21:30:25]

Because of ">" rather than ">="?  Because the QUIC version was broken and I
hadn't written tests for it; both now fixed.  

I've also updated this code to be explicit about the relationship to
kV3HighestPriority.

Ryan: Any idea why these are duplicated between SPDY and QUIC?

[Ryan Hamilton, 2016/05/12 22:25:46]

Because QuicPriority != SpdyPriority ... except then it turns out they are the
same. Long story short, it's a wart.

+             ? IDLE
+             : static_cast<RequestPriority>(MAXIMUM_PRIORITY - priority);
 }
 
 NET_EXPORT_PRIVATE void ConvertHeaderBlockToHttpRequestHeaders(
     const SpdyHeaderBlock& spdy_headers,
     HttpRequestHeaders* http_headers) {
   for (const auto& it : spdy_headers) {
     base::StringPiece key = it.first;
     if (key[0] == ':') {
       key.remove_prefix(1);
     }
@@ skipping 19 matching lines @@
   url.append(it->second.as_string());
 
   it = headers.find(":path");
   if (it == headers.end())
     return GURL();
   url.append(it->second.as_string());
   return GURL(url);
 }
 
 }  // namespace net