Support parsing a Sec-WebSocket-Extensions header with multiple elements

net/server/web_socket_encoder.cc

 // Copyright 2014 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/server/web_socket_encoder.h"
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "net/base/io_buffer.h"
@@ skipping 215 matching lines @@
 
   if (deflate) {
     return new WebSocketEncoder(false /* is_server */, client_window_bits,
                                 server_window_bits, client_no_context_takeover);
   } else {
     return new WebSocketEncoder(false /* is_server */);
   }
 }
 
 // static
-void WebSocketEncoder::ParseExtensions(const std::string& extensions,
+void WebSocketEncoder::ParseExtensions(const std::string& header_value,
                                        bool* deflate,
                                        bool* has_client_window_bits,
                                        int* client_window_bits,
                                        int* server_window_bits,
                                        bool* client_no_context_takeover,
                                        bool* server_no_context_takeover) {
   *deflate = false;
   *has_client_window_bits = false;
   *client_window_bits = 15;
   *server_window_bits = 15;
   *client_no_context_takeover = false;
   *server_no_context_takeover = false;
 
-  if (extensions.empty())
+  if (header_value.empty())
     return;
 
-  // TODO(dgozman): split extensions header if another extension is introduced.
   WebSocketExtensionParser parser;
-  parser.Parse(extensions);
+  parser.Parse(header_value);
   if (parser.has_error())
     return;
-  if (parser.extension().name() != "permessage-deflate")
-    return;
+  const std::vector<WebSocketExtension>& extensions = parser.extensions();
+  // TODO(tyoshino): Fail if this method is used for parsing a response and
+  // there're multiple permessage-deflate extensions or there is any unknown

[eroman, 2015/03/31 21:11:12]

there're --> there are
there is any unknown --> there are any unknown

[tyoshino (SeeGerritForStatus), 2015/04/01 04:57:57]

Done.

+  // extensions.
+  for (size_t i = 0; i < extensions.size(); ++i) {

[eroman, 2015/03/31 21:11:12]

nit: You use a traditional for loop here, however in the inner loop it is a
C++11 style "for in" loop. For consistency I suggest using a for-in in both
locations.

[tyoshino (SeeGerritForStatus), 2015/04/01 04:57:57]

Done.

+    if (extensions[i].name() != "permessage-deflate") {
+      continue;
+    }
 
-  const std::vector<WebSocketExtension::Parameter>& parameters =
-      parser.extension().parameters();
-  for (const auto& param : parameters) {
-    const std::string& name = param.name();
-    if (name == "client_max_window_bits") {
-      *has_client_window_bits = true;
-      if (param.HasValue()) {
+    const std::vector<WebSocketExtension::Parameter>& parameters =
+        extensions[i].parameters();
+    for (const auto& param : parameters) {
+      const std::string& name = param.name();
+      // TODO(tyoshino): Fail the connection when an invalid value is given.
+      if (name == "client_max_window_bits") {
+        *has_client_window_bits = true;
+        if (param.HasValue()) {
+          int bits = 0;
+          if (base::StringToInt(param.value(), &bits) && bits >= 8 &&
+              bits <= 15) {
+            *client_window_bits = bits;
+          }
+        }
+      }
+      if (name == "server_max_window_bits" && param.HasValue()) {
         int bits = 0;
         if (base::StringToInt(param.value(), &bits) && bits >= 8 && bits <= 15)
-          *client_window_bits = bits;
+          *server_window_bits = bits;
       }
+      if (name == "client_no_context_takeover")
+        *client_no_context_takeover = true;
+      if (name == "server_no_context_takeover")
+        *server_no_context_takeover = true;
     }
-    if (name == "server_max_window_bits" && param.HasValue()) {
-      int bits = 0;
-      if (base::StringToInt(param.value(), &bits) && bits >= 8 && bits <= 15)
-        *server_window_bits = bits;
-    }
-    if (name == "client_no_context_takeover")
-      *client_no_context_takeover = true;
-    if (name == "server_no_context_takeover")
-      *server_no_context_takeover = true;
+    *deflate = true;
+
+    break;
   }
-  *deflate = true;
 }
 
 WebSocketEncoder::WebSocketEncoder(bool is_server) : is_server_(is_server) {
 }
 
 WebSocketEncoder::WebSocketEncoder(bool is_server,
                                    int deflate_bits,
                                    int inflate_bits,
                                    bool no_context_takeover)
     : is_server_(is_server) {
@@ skipping 72 matching lines @@
     return false;
   scoped_refptr<IOBufferWithSize> buffer =
       deflater_->GetOutput(deflater_->CurrentOutputSize());
   if (!buffer.get())
     return false;
   *output = std::string(buffer->data(), buffer->size());
   return true;
 }
 
 }  // namespace net