Add Bus::ShutdownOnDBusThreadAndBlock() and remove bus::Shutdown()

dbus/bus.h

Index: dbus/bus.h
diff --git a/dbus/bus.h b/dbus/bus.h
index 792eb8310d32c79b1eb29d1468ea1be027db54ee..bb81b32f9406441d846b2643770dc5198f979673 100644
--- a/dbus/bus.h
+++ b/dbus/bus.h
@@ -14,6 +14,7 @@
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/synchronization/waitable_event.h"
 #include "base/threading/platform_thread.h"
 #include "base/tracked_objects.h"
 
@@ -225,6 +226,18 @@ class Bus : public base::RefCountedThreadSafe<Bus> {
   // Must be called in the origin thread.
   virtual void Shutdown(OnShutdownCallback callback);
 
+  // Similar to ShutdownAndBlock(), but this function is used to
+  // synchronously shut down the bus that uses the D-Bus thread. This
+  // function is intended to be used at the very end of the browser
+  // shutdown, where it makes more sense to shut down the bus
+  // synchronously, than trying to make it asynchronous.
+  //
+  // BLOCKING CALL, but must be called in the origin thread.
+  virtual void ShutdownAndBlockWithDBusThread();

[stevenjb, 2011/09/01 17:53:44]

Do we need to expose both ShutdownAndBlock and ShutdownAndBlockWithDBusThread in
the public API, or could we make this ShutdownAndBlock, and the make the
existing function private, e.g. ShutdownAndBlockInternal? It seems a bit
excessive to have three public Shutdown methods.

[satorux1, 2011/09/01 17:57:30]

ShutdownAndBlock() is already used in wifi_data_provider_linux.cc, that runs on
its own thread.

ShutdownAndBlockWithDBusThread() will be used.

Shutdown() is currently only used in tests. This can be removed, as we probably
don't use it in the production code.

[stevenjb, 2011/09/01 18:19:33]

OK. In that case I suggest we name this ShutdownOnDBusThreadAndBlock(), and make
Shutdown() private (with tests as friends) or remove it.

+
+  // Returns true if the shutdown has been completed.
+  bool shutdown_completed() { return shutdown_completed_; }
+
   //
   // The public functions below are not intended to be used in client
   // code. These are used to implement ObjectProxy and ExportedObject.
@@ -384,6 +397,9 @@ class Bus : public base::RefCountedThreadSafe<Bus> {
   // Helper function used for Shutdown().
   void ShutdownInternal(OnShutdownCallback callback);
 
+  // Helper function used for ShutdownAndBlockWithDBusThread().
+  void ShutdownAndBlockWithDBusThreadInternal();
+
   // Processes the all incoming data to the connection, if any.
   //
   // BLOCKING CALL.
@@ -427,6 +443,7 @@ class Bus : public base::RefCountedThreadSafe<Bus> {
   const BusType bus_type_;
   const ConnectionType connection_type_;
   base::Thread* dbus_thread_;
+  base::WaitableEvent on_shutdown_;
   DBusConnection* connection_;
 
   MessageLoop* origin_loop_;
@@ -455,6 +472,7 @@ class Bus : public base::RefCountedThreadSafe<Bus> {
   ExportedObjectTable exported_object_table_;
 
   bool async_operations_set_up_;
+  bool shutdown_completed_;
 
   // Counters to make sure that OnAddWatch()/OnRemoveWatch() and
   // OnAddTimeout()/OnRemoveTimeou() are balanced.