Gets presentation ID from route ID upon route creation, and overrides previous presentation ID with…

chrome/browser/media/router/media_route.cc

 // Copyright 2015 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 "chrome/browser/media/router/media_route.h"
 
 #include "base/logging.h"
 #include "chrome/browser/media/router/media_source.h"
 
+namespace {
+const char kRouteUrnPrefix[] = "urn:x-org.chromium:media:route:";
+}
+
 namespace media_router {
 
 MediaRoute::MediaRoute(const MediaRoute::Id& media_route_id,
                        const MediaSource& media_source,
                        const MediaSink& media_sink,
                        const std::string& description,
                        bool is_local)
     : media_route_id_(media_route_id),
       media_source_(media_source),
       media_sink_(media_sink),
       description_(description),
       is_local_(is_local),
       state_(MEDIA_ROUTE_STATE_NEW) {
 }
 
 MediaRoute::~MediaRoute() {
 }
 
 bool MediaRoute::Equals(const MediaRoute& other) const {
   return media_route_id_ == other.media_route_id_;
 }
 
+std::pair<std::string, std::string> GetPresentationIdAndUrl(

[Kevin M, 2015/06/24 23:02:06]

This needs a plain description of how the URLs are formatted.

[haibinlu, 2015/06/24 23:25:12]

Done.

+    const MediaRoute::Id& id) {
+  if (id.find(kRouteUrnPrefix) != 0) {
+    LOG(ERROR) << "Invalid media route ID. Expecting prefix "
+               << kRouteUrnPrefix;
+    return std::make_pair(std::string(), std::string());
+  }
+  size_t prefix_len = strlen(kRouteUrnPrefix);
+  size_t first_delim = id.find("/");

[Kevin M, 2015/06/24 23:02:06]

Use a string splitting function (base/strings/string_split.h) so you don't have
to call find repeatedly, or compute substrings.

[haibinlu, 2015/06/24 23:25:12]

string_split will has issue because the URL can have delim '/'.  

+  if (first_delim == std::string::npos || first_delim == prefix_len) {
+    LOG(ERROR) << "Invalid media route ID. Expecting presentation ID.";
+    return std::make_pair(std::string(), std::string());
+  }
+
+  std::string presentation_id = id.substr(prefix_len, first_delim - prefix_len);
+  size_t second_delim = id.find("/", first_delim + 1);
+  if (second_delim == std::string::npos || second_delim == first_delim + 1) {
+    LOG(ERROR) << "Invalid media route ID. Expecting sink.";
+    return std::make_pair(std::string(), std::string());
+  }
+
+  if (second_delim == id.size() - 1) {
+    LOG(ERROR) << "Invalid media route ID. Expecting source.";
+    return std::make_pair(std::string(), std::string());
+  }
+  std::string source = id.substr(second_delim + 1);
+  return std::make_pair(presentation_id, source);
+}
+
 }  // namespace media_router