Initial Contribution

1 files changed, 59 insertions, 0 deletions

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