SpdyUtils support coalescing multi-value headers.

net/quic/spdy_utils.cc

 // Copyright (c) 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.
 
 #include "net/quic/spdy_utils.h"
 
 #include <memory>
 #include <vector>
 
 #include "base/stl_util.h"
@@ skipping 111 matching lines @@
 
     if (std::any_of(name.begin(), name.end(), base::IsAsciiUpper<char>)) {
       DLOG(ERROR) << "Malformed header: Header name " << name
                   << " contains upper-case characters.";
       return false;
     }
 
     auto iter = headers->find(name);
     if (iter == headers->end()) {
       (*headers)[name] = p.second;
-    } else if (name == "cookie") {
-      // Obeys section 8.1.2.5 in RFC 7540 for cookie reconstruction.
-      headers->ReplaceOrAppendHeader(
-          name, base::StringPrintf("%s; %s", iter->second.as_string().c_str(),
-                                   p.second.c_str()));
     } else {
       // This header had multiple values, so it must be reconstructed.
-      string value = base::StringPrintf(
-          "%s%c%s", iter->second.as_string().c_str(), '\0', p.second.c_str());
-      headers->ReplaceOrAppendHeader(name, value);
+      StringPiece v = iter->second;
+      string s(v.data(), v.length());
+      if (name == "cookie") {
+        // Obeys section 8.1.2.5 in RFC 7540 for cookie reconstruction.
+        s.append("; ");
+      } else {
+        StringPiece("\0", 1).AppendToString(&s);
+      }
+      s.append(p.second);
+      headers->ReplaceOrAppendHeader(name, s);
     }
   }
 
   if (ContainsKey(*headers, "content-length")) {
     // Check whether multiple values are consistent.
     StringPiece content_length_header = (*headers)["content-length"];
     vector<string> values =
         base::SplitString(content_length_header, base::StringPiece("\0", 1),
                           base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
     for (const string& value : values) {
@@ skipping 96 matching lines @@
   return GURL(GetUrlFromHeaderBlock(headers)).host();
 }
 
 // static
 bool SpdyUtils::UrlIsValid(const SpdyHeaderBlock& headers) {
   string url(GetUrlFromHeaderBlock(headers));
   return url != "" && GURL(url).is_valid();
 }
 
 }  // namespace net