Added automatic update for plugins based on watching file changes.

chrome/browser/plugin_service.cc

Index: chrome/browser/plugin_service.cc
diff --git a/chrome/browser/plugin_service.cc b/chrome/browser/plugin_service.cc
index 0c8ee4c579650e0d8e4d7e3f96e5a364f6c8e4d2..10bed08b006af932219f67a66ae706a9084589af 100644
--- a/chrome/browser/plugin_service.cc
+++ b/chrome/browser/plugin_service.cc
@@ -8,6 +8,7 @@
 
 #include "base/command_line.h"
 #include "base/path_service.h"
+#include "base/stl_util-inl.h"
 #include "base/string_util.h"
 #include "base/threading/thread.h"
 #include "base/utf_string_conversions.h"
@@ -58,6 +59,31 @@ static void NotifyPluginsOfActivation() {
 }
 #endif
 
+static void PurgePluginListCache(bool reload_pages) {
+  for (RenderProcessHost::iterator it = RenderProcessHost::AllHostsIterator();
+       !it.IsAtEnd(); it.Advance()) {
+    it.GetCurrentValue()->Send(new ViewMsg_PurgePluginListCache(reload_pages));
+  }
+}
+
+// Delegate class for monitoring directories.
+class PluginDirWatcherDelegate : public FilePathWatcher::Delegate {
+  virtual void OnFilePathChanged(const FilePath& path) {
+    VLOG(1) << "Watched path changed : " << path.value();
+
+    // Make the plugin list update itself
+    webkit::npapi::PluginList::Singleton()->RefreshPlugins();
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE,

[Bernhard Bauer, 2011/01/10 13:27:20]

Is there are reason you're calling this method on the UI thread?

[jam, 2011/01/10 17:18:10]

yep RenderProcessHost lives on the UI thread

[pastarmovj, 2011/01/11 17:17:26]

It was a comment from John back than "since this is being called on the FILE
thread, PluginDirWatcherDelegate will get
called back on that thread.  It can't call RenderProcessHost::iterator since
RenderProcessHost is not thread-safe, and neither is its iterator.  You will
need to post a task to the UI thread to do this."

[pastarmovj, 2011/01/11 17:17:26]

Sorry I didn't post my answer earlier, when I had it written already - that
would have spent you the need to answer as well :)

+        NewRunnableFunction(&PurgePluginListCache, true));
+  }
+  virtual void OnError() {
+    // TODO(pastarmovj): Add some sensible error handling. Maybe silently
+    // stopping the watcher would be enough. Or possibly restart it.
+    NOTREACHED();
+  }
+};
+
 // static
 bool PluginService::enable_chrome_plugins_ = true;
 
@@ -85,7 +111,8 @@ void PluginService::EnableChromePlugins(bool enable) {
 PluginService::PluginService()
     : main_message_loop_(MessageLoop::current()),
       resource_dispatcher_host_(NULL),
-      ui_locale_(g_browser_process->GetApplicationLocale()) {
+      ui_locale_(g_browser_process->GetApplicationLocale()),
+      file_watcher_delegate_(new PluginDirWatcherDelegate()) {
   RegisterPepperPlugins();
 
   // Have the NPAPI plugin list search for Chrome plugins as well.
@@ -122,6 +149,9 @@ PluginService::PluginService()
 
   chrome::RegisterInternalGPUPlugin();
 
+  // Start watching for changes in the plugin list. This means watching
+  // for changes in the Windows registry keys and on both Windows and POSIX
+  // watch for changes in the paths that are expected to contain plugins.
 #if defined(OS_WIN)
   hkcu_key_.Create(
       HKEY_CURRENT_USER, webkit::npapi::kRegistryMozillaPlugins, KEY_NOTIFY);
@@ -145,6 +175,22 @@ PluginService::PluginService()
         user_data_dir.Append("Plugins"));
   }
 #endif
+  // Get the list of all paths for registering the FilePathWatchers
+  // that will track and if needed reload the list of plugins on runtime.
+  std::vector<FilePath> plugin_dirs_list;

[jam, 2011/01/10 17:18:10]

nit: plugin_dirs_ is enough, especially since list in this case is slightly
confusing since it's a vector and not a list

[pastarmovj, 2011/01/11 17:17:26]

That's true, thanks for the note :) Done.

+  webkit::npapi::PluginList::Singleton()->GetPluginDirectories(
+      &plugin_dirs_list);
+
+  for (size_t i = 0; i < plugin_dirs_list.size(); ++i) {
+    FilePathWatcher* watcher = new FilePathWatcher();
+    VLOG(1) << "Watching for changes in : " << plugin_dirs_list[i].value();

[Bernhard Bauer, 2011/01/10 13:27:20]

Nit: no space before the colon.

[pastarmovj, 2011/01/11 17:17:26]

Done.

+    BrowserThread::PostTask(
+        BrowserThread::FILE, FROM_HERE,
+        NewRunnableFunction(
+            &PluginService::RegisterFilePathWatcher,
+            watcher, plugin_dirs_list[i], file_watcher_delegate_));
+    file_watchers_.push_back(watcher);
+  }
 
   registrar_.Add(this, NotificationType::EXTENSION_LOADED,
                  NotificationService::AllSources());
@@ -168,6 +214,8 @@ PluginService::~PluginService() {
   hkcu_event_->Release();
   hklm_event_->Release();
 #endif
+  // Delete the file watchers to release the refcounted delegates.
+  STLDeleteElements(&file_watchers_);
 }
 
 void PluginService::LoadChromePlugins(
@@ -304,13 +352,6 @@ bool PluginService::GetFirstAllowedPluginInfo(
 #endif
 }
 
-static void PurgePluginListCache(bool reload_pages) {
-  for (RenderProcessHost::iterator it = RenderProcessHost::AllHostsIterator();
-       !it.IsAtEnd(); it.Advance()) {
-    it.GetCurrentValue()->Send(new ViewMsg_PurgePluginListCache(reload_pages));
-  }
-}
-
 void PluginService::OnWaitableEventSignaled(
     base::WaitableEvent* waitable_event) {
 #if defined(OS_WIN)
@@ -322,6 +363,9 @@ void PluginService::OnWaitableEventSignaled(
 
   webkit::npapi::PluginList::Singleton()->RefreshPlugins();
   PurgePluginListCache(true);
+#else
+  // This event should only get signaled on a Windows machine.
+  NOTREACHED();
 #endif  // defined(OS_WIN)
 }
 
@@ -386,7 +430,7 @@ void PluginService::Observe(NotificationType type,
       break;
     }
     default:
-      DCHECK(false);
+      NOTREACHED();
   }
 }
 
@@ -428,3 +472,11 @@ void PluginService::RegisterPepperPlugins() {
     webkit::npapi::PluginList::Singleton()->RegisterInternalPlugin(info);
   }
 }
+
+// static
+void PluginService::RegisterFilePathWatcher(
+    FilePathWatcher *watcher,
+    const FilePath& path,
+    FilePathWatcher::Delegate* delegate) {
+  DCHECK(watcher->Watch(path, delegate));

[Bernhard Bauer, 2011/01/10 13:27:20]

Isn't this whole line a no-op in a release build? I think you want to do

  bool result = ...;
  DCHECK(result);

[pastarmovj, 2011/01/11 17:17:26]

True. Sorry about that.

+}