1 files changed, 76 insertions, 0 deletions
diff --git a/mojo/public/cpp/bindings/lib/sync_handle_watcher.cc b/mojo/public/cpp/bindings/lib/sync_handle_watcher.cc
new file mode 100644
index 0000000000..f20af56b20
--- /dev/null
+++ b/mojo/public/cpp/bindings/lib/sync_handle_watcher.cc
@@ -0,0 +1,76 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "mojo/public/cpp/bindings/sync_handle_watcher.h"
+
+#include "base/logging.h"
+
+namespace mojo {
+
+SyncHandleWatcher::SyncHandleWatcher(
+    const Handle& handle,
+    MojoHandleSignals handle_signals,
+    const SyncHandleRegistry::HandleCallback& callback)
+    : handle_(handle),
+      handle_signals_(handle_signals),
+      callback_(callback),
+      registered_(false),
+      register_request_count_(0),
+      registry_(SyncHandleRegistry::current()),
+      destroyed_(new base::RefCountedData<bool>(false)) {}
+
+SyncHandleWatcher::~SyncHandleWatcher() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (registered_)
+    registry_->UnregisterHandle(handle_);
+
+  destroyed_->data = true;
+}
+
+void SyncHandleWatcher::AllowWokenUpBySyncWatchOnSameThread() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  IncrementRegisterCount();
+}
+
+bool SyncHandleWatcher::SyncWatch(const bool* should_stop) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  IncrementRegisterCount();
+  if (!registered_) {
+    DecrementRegisterCount();
+    return false;
+  }
+
+  // This object may be destroyed during the Wait() call. So we have to preserve
+  // the boolean that Wait uses.
+  auto destroyed = destroyed_;
+  const bool* should_stop_array[] = {should_stop, &destroyed->data};
+  bool result = registry_->Wait(should_stop_array, 2);
+
+  // This object has been destroyed.
+  if (destroyed->data)
+    return false;
+
+  DecrementRegisterCount();
+  return result;
+}
+
+void SyncHandleWatcher::IncrementRegisterCount() {
+  register_request_count_++;
+  if (!registered_) {
+    registered_ =
+        registry_->RegisterHandle(handle_, handle_signals_, callback_);
+  }
+}
+
+void SyncHandleWatcher::DecrementRegisterCount() {
+  DCHECK_GT(register_request_count_, 0u);
+
+  register_request_count_--;
+  if (register_request_count_ == 0 && registered_) {
+    registry_->UnregisterHandle(handle_);
+    registered_ = false;
+  }
+}
+
+}  // namespace mojo