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, 8 insertions, 3 deletions

diff --git a/chrome/browser/tab_contents/web_contents_view.h b/chrome/browser/tab_contents/web_contents_view.h
index 232b449..dc5362c 100644
--- a/chrome/browser/tab_contents/web_contents_view.h
+++ b/chrome/browser/tab_contents/web_contents_view.h
@@ -24,6 +24,10 @@ class WebContents;
 struct WebDropData;
 class WebKeyboardEvent;
 
+namespace base {
+class WaitableEvent;
+}
+
 // The WebContentsView is an interface that is implemented by the platform-
 // dependent web contents views. The WebContents uses this interface to talk to
 // them. View-related messages will also get forwarded directly to this class
@@ -152,8 +156,8 @@ class WebContentsView : public RenderViewHostDelegate::View {
   // created objects so that they can be associated with the given routes. When
   // they are shown later, we'll look them up again and pass the objects to
   // the Show functions rather than the route ID.
-  virtual WebContents* CreateNewWindowInternal(int route_id,
-                                               HANDLE modal_dialog_event) = 0;
+  virtual WebContents* CreateNewWindowInternal
+      (int route_id, base::WaitableEvent* modal_dialog_event) = 0;
   virtual RenderWidgetHostView* CreateNewWidgetInternal(int route_id,
                                                         bool activatable) = 0;
   virtual void ShowCreatedWindowInternal(WebContents* new_web_contents,
@@ -167,7 +171,8 @@ class WebContentsView : public RenderViewHostDelegate::View {
   // We implement these functions on RenderViewHostDelegate::View directly and
   // do some book-keeping associated with the request. The request is then
   // forwarded to *Internal which does platform-specific work.
-  virtual void CreateNewWindow(int route_id, HANDLE modal_dialog_event);
+  virtual void CreateNewWindow(int route_id,
+                               base::WaitableEvent* modal_dialog_event);
   virtual void CreateNewWidget(int route_id, bool activatable);
   virtual void ShowCreatedWindow(int route_id,
                                  WindowOpenDisposition disposition,