Removed Common

Change-Id: I01ea8f07220375c2ad9bc0092281d4f27c642303
diff --git a/aos/event.cc b/aos/event.cc
new file mode 100644
index 0000000..dd43dc8
--- /dev/null
+++ b/aos/event.cc
@@ -0,0 +1,58 @@
+#include "aos/event.h"
+
+#include <chrono>
+
+#include "aos/type_traits/type_traits.h"
+#include "aos/logging/logging.h"
+
+namespace aos {
+
+Event::Event() : impl_(0) {
+  static_assert(shm_ok<Event>::value,
+                "Event is not safe for use in shared memory.");
+}
+
+void Event::Wait() {
+  while (__atomic_load_n(&impl_, __ATOMIC_SEQ_CST) == 0) {
+    const int ret = futex_wait(&impl_);
+    if (ret != 0) {
+      CHECK_EQ(-1, ret);
+      PLOG(FATAL, "futex_wait(%p) failed", &impl_);
+    }
+  }
+}
+
+bool Event::WaitTimeout(monotonic_clock::duration timeout) {
+  ::std::chrono::seconds sec =
+      ::std::chrono::duration_cast<::std::chrono::seconds>(timeout);
+  ::std::chrono::nanoseconds nsec =
+      ::std::chrono::duration_cast<::std::chrono::nanoseconds>(timeout - sec);
+  struct timespec timeout_timespec;
+  timeout_timespec.tv_sec = sec.count();
+  timeout_timespec.tv_nsec = nsec.count();
+  while (true) {
+    if (__atomic_load_n(&impl_, __ATOMIC_SEQ_CST) != 0) {
+      return true;
+    }
+    const int ret = futex_wait_timeout(&impl_, &timeout_timespec);
+    if (ret != 0) {
+      if (ret == 2) return false;
+      CHECK_EQ(-1, ret);
+      PLOG(FATAL, "futex_wait(%p) failed", &impl_);
+    }
+  }
+}
+
+// We're not going to expose the number woken because that's not easily portable
+// to condition variable-based implementations.
+void Event::Set() {
+  if (futex_set(&impl_) == -1) {
+    PLOG(FATAL, "futex_set(%p) failed", &impl_);
+  }
+}
+
+bool Event::Clear() {
+  return !futex_unset(&impl_);
+}
+
+}  // namespace aos