auto import from //depot/cupcake/@135843
diff --git a/libs/surfaceflinger/Barrier.h b/libs/surfaceflinger/Barrier.h
new file mode 100644
index 0000000..e2bcf6a
--- /dev/null
+++ b/libs/surfaceflinger/Barrier.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_BARRIER_H
+#define ANDROID_BARRIER_H
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <utils/threads.h>
+
+namespace android {
+
+class Barrier
+{
+public:
+ inline Barrier() : state(CLOSED) { }
+ inline ~Barrier() { }
+ void open() {
+ // gcc memory barrier, this makes sure all memory writes
+ // have been issued by gcc. On an SMP system we'd need a real
+ // h/w barrier.
+ asm volatile ("":::"memory");
+ Mutex::Autolock _l(lock);
+ state = OPENED;
+ cv.broadcast();
+ }
+ void close() {
+ Mutex::Autolock _l(lock);
+ state = CLOSED;
+ }
+ void wait() const {
+ Mutex::Autolock _l(lock);
+ while (state == CLOSED) {
+ cv.wait(lock);
+ }
+ }
+private:
+ enum { OPENED, CLOSED };
+ mutable Mutex lock;
+ mutable Condition cv;
+ volatile int state;
+};
+
+}; // namespace android
+
+#endif // ANDROID_BARRIER_H