[net] Change order of RequestPriority to natural: higher > lower

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/string_number_conversions.h"
 #include "base/string_util.h"
@@ skipping 110 matching lines @@
     (*headers)[":scheme"] = info.url.scheme();
     (*headers)[":path"] = HttpUtil::PathForRequest(info.url);
     headers->erase("host"); // this is kinda insane, spdy 3 spec.
   }
 
 }
 
 SpdyPriority ConvertRequestPriorityToSpdyPriority(
     const RequestPriority priority,
     int protocol_version) {
-  DCHECK(HIGHEST <= priority && priority < NUM_PRIORITIES);
+  DCHECK_GE(priority, MINIMUM_PRIORITY);

[Ryan Hamilton, 2012/04/23 22:51:05]

One minor problem.  The CQ is about to land this CL:

https://chromiumcodereview.appspot.com/10187006/

It re-writes this method, and in particular eliminates the SPDY_PRIORITY_HIGHEST
symbol.  Not a big deal, but just FYI.

[szym, 2012/04/24 00:19:31]

Thanks for the heads up.

+  DCHECK_LT(priority, NUM_PRIORITIES);
   if (protocol_version == 2) {
     switch (priority) {
+      case HIGHEST:
+        return SPDY_PRIORITY_HIGHEST;
+      case MEDIUM:
+        return SPDY_PRIORITY_HIGHEST + 1;
+      case LOW:
+        return SPDY_PRIORITY_HIGHEST + 2;
       case LOWEST:
         return SPDY_PRIORITY_LOWEST - 1;
       case IDLE:
         return SPDY_PRIORITY_LOWEST;
       default:
-        return priority;
+        NOTREACHED();
+        return SpdyPriority();
     }
   } else {
-    return priority;
+    switch (priority) {

[szym, 2012/04/24 00:19:31]

Do you think this switch would be better expressed as: |return
static_cast<SpdyPriority>(HIGHEST - priority)|.

[Ryan Hamilton, 2012/04/24 00:42:11]

Yup, that sounds great.  The SPDY 2 case could be a similar expression, possibly
offset by 1 for IDLE and LOWEST.  (I did the moral equivalent of this in the new
code)

+      case HIGHEST:
+        return SPDY_PRIORITY_HIGHEST;
+      case MEDIUM:
+        return SPDY_PRIORITY_HIGHEST + 1;
+      case LOW:
+        return SPDY_PRIORITY_HIGHEST + 2;
+      case LOWEST:
+        return SPDY_PRIORITY_HIGHEST + 3;
+      case IDLE:
+        return SPDY_PRIORITY_HIGHEST + 4;
+      default:
+        NOTREACHED();
+        return SpdyPriority();
+    }
   }
 }
 
 GURL GetUrlFromHeaderBlock(const SpdyHeaderBlock& headers,
                            int protocol_version,
                            bool pushed) {
   // SPDY 2 server push urls are specified in a single "url" header.
   if (pushed && protocol_version == 2) {
       std::string url;
       SpdyHeaderBlock::const_iterator it;
@@ skipping 20 matching lines @@
   it = headers.find(path_header);
   if (it != headers.end())
     path = it->second;
 
   std::string url =  (scheme.empty() || host_port.empty() || path.empty())
       ? "" : scheme + "://" + host_port + path;
   return GURL(url);
 }
 
 }  // namespace net