1 files changed, 123 insertions, 0 deletions
diff --git a/src/cpp/common/alarm.cc b/src/cpp/common/alarm.cc
new file mode 100644
index 0000000000..0eecbb6261
--- /dev/null
+++ b/src/cpp/common/alarm.cc
@@ -0,0 +1,123 @@
+/*
+ * Copyright 2018 gRPC authors.
+ *
+ * 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.
+ *
+ */
+
+#include <grpc++/alarm.h>
+
+#include <memory>
+
+#include <grpc++/completion_queue.h>
+#include <grpc++/impl/grpc_library.h>
+#include <grpc++/support/time.h>
+#include <grpc/support/log.h>
+#include <grpc/support/port_platform.h>
+#include "src/core/lib/iomgr/exec_ctx.h"
+#include "src/core/lib/iomgr/timer.h"
+#include "src/core/lib/surface/completion_queue.h"
+
+#include <grpc/support/log.h>
+#include "src/core/lib/debug/trace.h"
+
+namespace grpc {
+
+namespace internal {
+class AlarmImpl : public CompletionQueueTag {
+ public:
+  AlarmImpl() : cq_(nullptr), tag_(nullptr) {
+    gpr_ref_init(&refs_, 1);
+    grpc_timer_init_unset(&timer_);
+    GRPC_CLOSURE_INIT(&on_alarm_,
+                      [](void* arg, grpc_error* error) {
+                        // queue the op on the completion queue
+                        AlarmImpl* alarm = static_cast<AlarmImpl*>(arg);
+                        alarm->Ref();
+                        grpc_cq_end_op(
+                            alarm->cq_, alarm, error,
+                            [](void* arg, grpc_cq_completion* completion) {},
+                            arg, &alarm->completion_);
+                      },
+                      this, grpc_schedule_on_exec_ctx);
+  }
+  ~AlarmImpl() {
+    grpc_core::ExecCtx exec_ctx;
+    if (cq_ != nullptr) {
+      GRPC_CQ_INTERNAL_UNREF(cq_, "alarm");
+    }
+  }
+  bool FinalizeResult(void** tag, bool* status) override {
+    *tag = tag_;
+    Unref();
+    return true;
+  }
+  void Set(CompletionQueue* cq, gpr_timespec deadline, void* tag) {
+    grpc_core::ExecCtx exec_ctx;
+    GRPC_CQ_INTERNAL_REF(cq->cq(), "alarm");
+    cq_ = cq->cq();
+    tag_ = tag;
+    GPR_ASSERT(grpc_cq_begin_op(cq_, this));
+    grpc_timer_init(&timer_, grpc_timespec_to_millis_round_up(deadline),
+                    &on_alarm_);
+  }
+  void Cancel() {
+    grpc_core::ExecCtx exec_ctx;
+    grpc_timer_cancel(&timer_);
+  }
+  void Destroy() {
+    Cancel();
+    Unref();
+  }
+
+ private:
+  void Ref() { gpr_ref(&refs_); }
+  void Unref() {
+    if (gpr_unref(&refs_)) {
+      delete this;
+    }
+  }
+
+  grpc_timer timer_;
+  gpr_refcount refs_;
+  grpc_closure on_alarm_;
+  grpc_cq_completion completion_;
+  // completion queue where events about this alarm will be posted
+  grpc_completion_queue* cq_;
+  void* tag_;
+};
+}  // namespace internal
+
+static internal::GrpcLibraryInitializer g_gli_initializer;
+
+Alarm::Alarm() : alarm_(new internal::AlarmImpl()) {
+  g_gli_initializer.summon();
+}
+
+void Alarm::SetInternal(CompletionQueue* cq, gpr_timespec deadline, void* tag) {
+  // Note that we know that alarm_ is actually an internal::AlarmImpl
+  // but we declared it as the base pointer to avoid a forward declaration
+  // or exposing core data structures in the C++ public headers.
+  // Thus it is safe to use a static_cast to the subclass here, and the
+  // C++ style guide allows us to do so in this case
+  static_cast<internal::AlarmImpl*>(alarm_)->Set(cq, deadline, tag);
+}
+
+Alarm::~Alarm() {
+  if (alarm_ != nullptr) {
+    static_cast<internal::AlarmImpl*>(alarm_)->Destroy();
+  }
+}
+
+void Alarm::Cancel() { static_cast<internal::AlarmImpl*>(alarm_)->Cancel(); }
+}  // namespace grpc