Add a working WeakRealmNotifier for Node

Uses libuv APIs to async schedule onto the default Node run loop.

src/impl/node/weak_realm_notifier.cpp

@@ -0,0 +1,74 @@
+////////////////////////////////////////////////////////////////////////////
+//
+// Copyright 2016 Realm Inc.
+//
+// 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 "impl/weak_realm_notifier.hpp"
+
+#include "shared_realm.hpp"
+
+using namespace realm;
+using namespace realm::_impl;
+
+WeakRealmNotifier::WeakRealmNotifier(const std::shared_ptr<Realm>& realm, bool cache)
+: WeakRealmNotifierBase(realm, cache)
+, m_handle(new uv_async_t)
+{
+    m_handle->data = new std::weak_ptr<Realm>(realm);
+
+    // This assumes that only one thread matters: the main thread (default loop).
+    uv_async_init(uv_default_loop(), m_handle, [](uv_async_t* handle) {
+        auto realm_weak_ptr = static_cast<std::weak_ptr<Realm>*>(handle->data);
+        auto realm = realm_weak_ptr->lock();
+
+        if (realm) {
+            realm->notify();
+        }
+    });
+}
+
+WeakRealmNotifier::WeakRealmNotifier(WeakRealmNotifier&& rgt)
+: WeakRealmNotifierBase(std::move(rgt))
+{
+    rgt.m_handle = nullptr;
+}
+
+WeakRealmNotifier& WeakRealmNotifier::operator=(WeakRealmNotifier&& rgt)
+{
+    WeakRealmNotifierBase::operator=(std::move(rgt));
+    m_handle = rgt.m_handle;
+    rgt.m_handle = nullptr;
+
+    return *this;
+}
+
+WeakRealmNotifier::~WeakRealmNotifier()
+{
+    if (m_handle) {
+        uv_close((uv_handle_t*)m_handle, [](uv_handle_t* handle) {
+            auto realm_weak_ptr = static_cast<std::weak_ptr<Realm>*>(handle->data);
+            delete realm_weak_ptr;
+            delete handle;
+        });
+    }
+}
+
+void WeakRealmNotifier::notify()
+{
+    if (m_handle) {
+        uv_async_send(m_handle);
+    }
+}

src/impl/node/weak_realm_notifier.hpp

@@ -0,0 +1,47 @@
+////////////////////////////////////////////////////////////////////////////
+//
+// Copyright 2016 Realm Inc.
+//
+// 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 <uv.h>
+
+#include "impl/weak_realm_notifier_base.hpp"
+
+namespace realm {
+class Realm;
+
+namespace _impl {
+
+class WeakRealmNotifier : public WeakRealmNotifierBase {
+public:
+    WeakRealmNotifier(const std::shared_ptr<Realm>& realm, bool cache);
+    ~WeakRealmNotifier();
+
+    WeakRealmNotifier(WeakRealmNotifier&&);
+    WeakRealmNotifier& operator=(WeakRealmNotifier&&);
+
+    WeakRealmNotifier(const WeakRealmNotifier&) = delete;
+    WeakRealmNotifier& operator=(const WeakRealmNotifier&) = delete;
+
+    // Asynchronously call notify() on the Realm on the main thread.
+    void notify();
+
+private:
+    uv_async_t* m_handle;
+};
+
+} // namespace _impl
+} // namespace realm

src/impl/weak_realm_notifier.hpp

@@ -21,7 +21,9 @@
 
 #include <realm/util/features.h>
 
-#if REALM_PLATFORM_APPLE
+#if REALM_PLATFORM_NODE
+#include "impl/node/weak_realm_notifier.hpp"
+#elif REALM_PLATFORM_APPLE
 #include "impl/apple/weak_realm_notifier.hpp"
 #else
 #include "impl/generic/weak_realm_notifier.hpp"