1 files changed, 79 insertions, 0 deletions
diff --git a/widget/cocoa/WidgetTraceEvent.mm b/widget/cocoa/WidgetTraceEvent.mm
new file mode 100644
index 0000000000..54fe497e3b
--- /dev/null
+++ b/widget/cocoa/WidgetTraceEvent.mm
@@ -0,0 +1,79 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <Cocoa/Cocoa.h>
+#include "CustomCocoaEvents.h"
+#include <Foundation/NSAutoreleasePool.h>
+#include <mozilla/CondVar.h>
+#include <mozilla/Mutex.h>
+#include "mozilla/WidgetTraceEvent.h"
+
+using mozilla::CondVar;
+using mozilla::Mutex;
+using mozilla::MutexAutoLock;
+
+namespace {
+
+Mutex* sMutex = NULL;
+CondVar* sCondVar = NULL;
+bool sTracerProcessed = false;
+
+}  // namespace
+
+namespace mozilla {
+
+bool InitWidgetTracing() {
+  sMutex = new Mutex("Event tracer thread mutex");
+  sCondVar = new CondVar(*sMutex, "Event tracer thread condvar");
+  return sMutex && sCondVar;
+}
+
+void CleanUpWidgetTracing() {
+  delete sMutex;
+  delete sCondVar;
+  sMutex = NULL;
+  sCondVar = NULL;
+}
+
+// This function is called from the main (UI) thread.
+void SignalTracerThread() {
+  if (!sMutex || !sCondVar) return;
+  MutexAutoLock lock(*sMutex);
+  if (!sTracerProcessed) {
+    sTracerProcessed = true;
+    sCondVar->Notify();
+  }
+}
+
+// This function is called from the background tracer thread.
+bool FireAndWaitForTracerEvent() {
+  MOZ_ASSERT(sMutex && sCondVar, "Tracing not initialized!");
+  NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
+  MutexAutoLock lock(*sMutex);
+  if (sTracerProcessed) {
+    // Things are out of sync. This is likely because we're in
+    // the middle of shutting down. Just return false and hope the
+    // tracer thread is quitting anyway.
+    return false;
+  }
+
+  // Post an application-defined event to the main thread's event queue
+  // and wait for it to get processed.
+  [NSApp postEvent:[NSEvent otherEventWithType:NSEventTypeApplicationDefined
+                                      location:NSMakePoint(0, 0)
+                                 modifierFlags:0
+                                     timestamp:0
+                                  windowNumber:0
+                                       context:NULL
+                                       subtype:kEventSubtypeTrace
+                                         data1:0
+                                         data2:0]
+           atStart:NO];
+  while (!sTracerProcessed) sCondVar->Wait();
+  sTracerProcessed = false;
+  [pool release];
+  return true;
+}
+
+}  // namespace mozilla