WaitableEvent is the replacement for Windows events. Previously in the code, a HANDLE from CreateEvent was used for signaling, both within a process and across processes.

WaitableEvent is the cross platform replacement for this. To convert:
  * HANDLE -> base::WaitableEvent*
  * ScopedHandle -> scoped_ptr<base::WaitableEvent>
  * CreateEvent -> new base::WaitableEvent
  * SetEvent -> base::WaitableEvent::Signal
  * ResetEvent -> base::WaitableEvent::Reset
  * ObjectWatcher -> base::WaitableEventWatcher
  * WaitForMultipleObjects -> static base::WaitableEvent::WaitMany

ObjectWatcher remains for Windows specific code. WaitableEventWatcher has an identical interface save,
  * It uses WaitableEvents, not HANDLEs
  * It returns void from StartWatching and StopWatcher, rather than errors. System internal errors are fatal to the address space

IMPORTANT: There are semantic differences between the different platforms. WaitableEvents on Windows are implemented on top of events. Windows events work across process and this is used mostly for modal dialog support. Windows events can be duplicated with DuplicateHandle.

On other platforms, WaitableEvent works only within a single process. In the future we shall have to replace the current uses of cross-process events with IPCs.

BEWARE: HANDLE, on Windows, is a void *. Since any pointer type coerces to void *, you can pass a WaitableEvent * where a HANDLE is expected without any build-time errors.

Review URL: http://codereview.chromium.org/16554


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@8126 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 3 insertions, 2 deletions

diff --git a/chrome/browser/browser_process.h b/chrome/browser/browser_process.h
index 18ce8be..adff28b 100644
--- a/chrome/browser/browser_process.h
+++ b/chrome/browser/browser_process.h
@@ -36,6 +36,7 @@ class SuspendController;
 
 namespace base {
 class Thread;
+class WaitableEvent;
 }
 namespace sandbox {
 class BrokerServices;
@@ -128,10 +129,10 @@ class BrowserProcess {
     ResourceDispatcherHost* rdh = resource_dispatcher_host();
     return rdh ? rdh->download_request_manager() : NULL;
   }
+#endif
 
   // Returns an event that is signaled when the browser shutdown.
-  virtual HANDLE shutdown_event() = 0;
-#endif
+  virtual base::WaitableEvent* shutdown_event() = 0;
 
   // Returns a reference to the user-data-dir based profiles vector.
   std::vector<std::wstring>& user_data_dir_profiles() {