Some cleanup to the PluginList Singleton.

 - Remove unneeded ref counting.
 - Remove a static constructor (scoped_refptr).
 - Remove a leak (extra_plugin_paths_).

This slightly changes the code, since PlatformInit could be called before Singleton, via AddExtraPluginPaths.  I don't think this should be a problem.

Review URL: http://codereview.chromium.org/18454


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@8382 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 35 insertions, 31 deletions

diff --git a/webkit/glue/plugins/plugin_list.cc b/webkit/glue/plugins/plugin_list.cc
index a32fe62..4484fa3 100644
--- a/webkit/glue/plugins/plugin_list.cc
+++ b/webkit/glue/plugins/plugin_list.cc
@@ -6,6 +6,7 @@
 
 #include "webkit/glue/plugins/plugin_list.h"
 
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/string_util.h"
 #include "base/time.h"
@@ -19,33 +20,30 @@
 #include "webkit/glue/plugins/plugin_constants_win.h"
 #endif
 
-namespace NPAPI
-{
+namespace NPAPI {
 
-scoped_refptr<PluginList> PluginList::singleton_;
-
-// Extra paths to search.
-static std::vector<FilePath>* extra_plugin_paths_ = NULL;
+base::LazyInstance<PluginList> g_singleton(base::LINKER_INITIALIZED);
 
+// static
 PluginList* PluginList::Singleton() {
-  if (singleton_.get() == NULL) {
-    singleton_ = new PluginList();
-    singleton_->LoadPlugins(false);
+  PluginList* singleton = g_singleton.Pointer();
+  if (!singleton->plugins_loaded_) {
+    singleton->LoadPlugins(false);
+    DCHECK(singleton->plugins_loaded_);
   }
-
-  return singleton_;
+  return singleton;
 }
 
+// static
 void PluginList::AddExtraPluginPath(const FilePath& plugin_path) {
-  DCHECK(!singleton_.get() || !singleton_->plugins_loaded_);
+  // We access the singleton directly, and not through Singleton(), since
+  // we don't want LoadPlugins() to be called.
+  DCHECK(!g_singleton.Pointer()->plugins_loaded_);
 
-  if (!extra_plugin_paths_)
-    extra_plugin_paths_ = new std::vector<FilePath>;
-  extra_plugin_paths_->push_back(plugin_path);
+  g_singleton.Pointer()->extra_plugin_paths_.push_back(plugin_path);
 }
 
-PluginList::PluginList() :
-    plugins_loaded_(false) {
+PluginList::PluginList() : plugins_loaded_(false) {
   PlatformInit();
 }
 
@@ -67,10 +65,9 @@ void PluginList::LoadPlugins(bool refresh) {
     LoadPluginsFromDir(directories_to_scan[i]);
   }
 
-  if (extra_plugin_paths_) {
-    for (size_t i = 0; i < extra_plugin_paths_->size(); ++i)
-      LoadPlugin((*extra_plugin_paths_)[i]);
-  }
+  for (size_t i = 0; i < extra_plugin_paths_.size(); ++i)
+    LoadPlugin(extra_plugin_paths_[i]);
+  extra_plugin_paths_.clear();
 
   if (webkit_glue::IsDefaultPluginEnabled())
     LoadPlugin(FilePath(kDefaultPluginLibraryName));
diff --git a/webkit/glue/plugins/plugin_list.h b/webkit/glue/plugins/plugin_list.h
index 3b1a76d..9c4efef 100644
--- a/webkit/glue/plugins/plugin_list.h
+++ b/webkit/glue/plugins/plugin_list.h
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// TODO: Need mechanism to cleanup the static instance
-
 #ifndef WEBKIT_GLUE_PLUGIN_PLUGIN_LIST_H__
 #define WEBKIT_GLUE_PLUGIN_PLUGIN_LIST_H__
 
@@ -18,6 +16,13 @@
 
 class GURL;
 
+namespace base {
+
+template <typename T>
+struct DefaultLazyInstanceTraits;
+
+}  // namespace base
+
 namespace NPAPI
 {
 
@@ -33,14 +38,12 @@ class PluginInstance;
 // the machine-wide and user plugin directories and loads anything that has
 // the correct types. On Linux, it walks the plugin directories as well
 // (e.g. /usr/lib/browser-plugins/).
-class PluginList : public base::RefCounted<PluginList> {
+class PluginList {
  public:
-  // Gets the one instance of the PluginList.
-  //
-  // Accessing the singleton causes the PluginList to look on
-  // disk for existing plugins.  It does not actually load
-  // libraries, that will only happen when you initialize
-  // the plugin for the first time.
+  // Gets the one instance of the PluginList.  Accessing the singleton causes
+  // the PluginList to look on disk for existing plugins.  It does not actually
+  // load libraries, that will only happen when you initialize the plugin for
+  // the first time.
   static PluginList* Singleton();
 
   // Add an extra plugin to load when we actually do the loading.  This is
@@ -145,12 +148,16 @@ class PluginList : public base::RefCounted<PluginList> {
   // Internals
   //
 
-  static scoped_refptr<PluginList> singleton_;
   bool plugins_loaded_;
 
   // Contains information about the available plugins.
   std::vector<WebPluginInfo> plugins_;
 
+  // Extra plugin paths that we want to search when loading.
+  std::vector<FilePath> extra_plugin_paths_;
+
+  friend struct base::DefaultLazyInstanceTraits<PluginList>;
+
   DISALLOW_EVIL_CONSTRUCTORS(PluginList);
 };