Return matching plug-ins in the sorted order (by version number).

content/common/plugin_list.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 "content/common/plugin_list.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/version.h"
 #include "content/public/common/content_switches.h"
 #include "net/base/mime_util.h"
 #include "url/gurl.h"
 
 #if defined(OS_WIN)
 #include "content/common/plugin_constants_win.h"
 #endif
 
 namespace content {
 
@@ skipping 135 matching lines @@
         mime_type.description.erase(ext);
       }
     }
 
     parsed_mime_types->push_back(mime_type);
   }
 
   return true;
 }
 
+bool PluginList::VersionComparator::operator()(const WebPluginInfo& lhs,
+                                               const WebPluginInfo& rhs) const {
+  Version lhs_version;
+  Version rhs_version;
+  WebPluginInfo::CreateVersionFromString(lhs.version, &lhs_version);
+  WebPluginInfo::CreateVersionFromString(rhs.version, &rhs_version);
+  if (!lhs_version.IsValid())
+    lhs_version = Version("0");
+  if (!rhs_version.IsValid())
+    rhs_version = Version("0");
+
+  return lhs_version.CompareTo(rhs_version) > 0;
+}
+
 PluginList::PluginList()
     : loading_state_(LOADING_STATE_NEEDS_REFRESH),
       plugins_discovery_disabled_(false) {
 }
 
 void PluginList::LoadPlugins(bool include_npapi) {
   {
     base::AutoLock lock(lock_);
     if (loading_state_ == LOADING_STATE_UP_TO_DATE)
       return;
@@ skipping 134 matching lines @@
     std::vector<WebPluginInfo>* info,
     std::vector<std::string>* actual_mime_types) {
   DCHECK(mime_type == StringToLowerASCII(mime_type));
   DCHECK(info);
 
   if (!use_stale)
     LoadPlugins(include_npapi);
   base::AutoLock lock(lock_);
   if (use_stale)
     *use_stale = (loading_state_ != LOADING_STATE_UP_TO_DATE);
-  info->clear();
   if (actual_mime_types)
     actual_mime_types->clear();
 
   std::set<base::FilePath> visited_plugins;
+  // Instead of pushing elements to |info| directly, we add it to
+  // |matched_plugins| first so that they are sorted by version number.
+  // Returning matched plugins in sorted order ensures that the first plugin
+  // that is tried is always the one with the latest version. This helps in the
+  // case when we have more than one plugin for given mime type. If we would
+  // pick the one that is older, we would decide to block it because it's
+  // outdated and wouldn't give the newer plugin a chance to run.
+  std::multiset<WebPluginInfo, VersionComparator> matched_plugins;
 
   // Add in plugins by mime type.
   for (size_t i = 0; i < plugins_list_.size(); ++i) {
     if (SupportsType(plugins_list_[i], mime_type, allow_wildcard)) {
       base::FilePath path = plugins_list_[i].path;
       if (visited_plugins.insert(path).second) {
-        info->push_back(plugins_list_[i]);
+        matched_plugins.insert(plugins_list_[i]);
         if (actual_mime_types)
           actual_mime_types->push_back(mime_type);
       }
     }
   }
 
   // Add in plugins by url.
   // We do not permit URL-sniff based plug-in MIME type overrides aside from
   // the case where the "type" was initially missing.
   // We collected stats to determine this approach isn't a major compat issue,
   // and we defend against content confusion attacks in various cases, such
   // as when the user doesn't have the Flash plug-in enabled.
   std::string path = url.path();
   std::string::size_type last_dot = path.rfind('.');
   if (last_dot != std::string::npos && mime_type.empty()) {
     std::string extension = StringToLowerASCII(std::string(path, last_dot+1));
     std::string actual_mime_type;
     for (size_t i = 0; i < plugins_list_.size(); ++i) {
       if (SupportsExtension(plugins_list_[i], extension, &actual_mime_type)) {
         base::FilePath path = plugins_list_[i].path;
         if (visited_plugins.insert(path).second) {
-          info->push_back(plugins_list_[i]);
+          matched_plugins.insert(plugins_list_[i]);
           if (actual_mime_types)
             actual_mime_types->push_back(actual_mime_type);
         }
       }
     }
   }
+
+  // Assign in sorted order.
+  info->assign(matched_plugins.begin(), matched_plugins.end());
 }
 
 bool PluginList::SupportsType(const WebPluginInfo& plugin,
                               const std::string& mime_type,
                               bool allow_wildcard) {
   // Webkit will ask for a plugin to handle empty mime types.
   if (mime_type.empty())
     return false;
 
   for (size_t i = 0; i < plugin.mime_types.size(); ++i) {
@@ skipping 31 matching lines @@
                 plugin_path);
   if (it != extra_plugin_paths_.end())
     extra_plugin_paths_.erase(it);
 }
 
 PluginList::~PluginList() {
 }
 
 
 }  // namespace content