From b60fbc2692e16c868616aa8a76c4524b945d6881 Mon Sep 17 00:00:00 2001
From: Ari Lazier <alazier@gmail.com>
Date: Fri, 27 May 2016 15:29:06 -0700
Subject: [PATCH] get basics workings

---
 examples/ReactExample/components/todo-app.js  | 15 ++++----
 .../src/impl/collection_notifier.cpp          | 36 +++----------------
 .../src/impl/collection_notifier.hpp          | 14 +-------
 3 files changed, 13 insertions(+), 52 deletions(-)

diff --git a/examples/ReactExample/components/todo-app.js b/examples/ReactExample/components/todo-app.js
index 5e497e4e..b75184b0 100644
--- a/examples/ReactExample/components/todo-app.js
+++ b/examples/ReactExample/components/todo-app.js
@@ -41,17 +41,19 @@ export default class TodoApp extends Component {
 
         // This is a Results object, which will live-update.
         this.todoLists = realm.objects('TodoList');
-        this.todoLists.addListener(function(name, changes) {
-            console.log("changed: " + JSON.stringify(changes));
-        });
-        console.log("registered listener");
-
         if (this.todoLists.length < 1) {
             realm.write(() => {
                 realm.create('TodoList', {name: 'Todo List'});
             });
         }
 
+        this.anotherList = realm.objects('TodoList');
+        this.anotherList.addListener(function(name, changes) {
+            console.log("changed: " + JSON.stringify(changes));
+        });
+        console.log("registered listener");
+
+
         // Bind all the methods that we will be passing as props.
         this.renderScene = this.renderScene.bind(this);
         this._addNewTodoList = this._addNewTodoList.bind(this);
@@ -83,7 +85,6 @@ export default class TodoApp extends Component {
             component: TodoListView,
             passProps: {
                 ref: 'listView',
-                items: this.todoLists,
                 extraItems: extraItems,
                 onPressItem: this._onPressTodoList,
             },
@@ -109,7 +110,7 @@ export default class TodoApp extends Component {
     }
 
     renderScene(route) {
-        return <route.component {...route.passProps} />
+        return <route.component items={this.todoLists} {...route.passProps} />
     }
 
     _addNewTodoItem(list) {
diff --git a/src/object-store/src/impl/collection_notifier.cpp b/src/object-store/src/impl/collection_notifier.cpp
index 817f329e..ae2d074c 100644
--- a/src/object-store/src/impl/collection_notifier.cpp
+++ b/src/object-store/src/impl/collection_notifier.cpp
@@ -178,10 +178,8 @@ size_t CollectionNotifier::add_callback(CollectionChangeCallback callback)
     }
 
     m_callbacks.push_back({std::move(callback), token, false});
-    if (m_callback_index == npos) { // Don't need to wake up if we're already sending notifications
-        Realm::Internal::get_coordinator(*m_realm).send_commit_notifications();
-        m_have_callbacks = true;
-    }
+    Realm::Internal::get_coordinator(*m_realm).send_commit_notifications();
+
     return token;
 }
 
@@ -200,22 +198,13 @@ void CollectionNotifier::remove_callback(size_t token)
             return;
         }
 
-        size_t idx = distance(begin(m_callbacks), it);
-        if (m_callback_index != npos && m_callback_index >= idx) {
-            --m_callback_index;
-        }
-
-        old = std::move(*it);
         m_callbacks.erase(it);
-
-        m_have_callbacks = !m_callbacks.empty();
     }
 }
 
 void CollectionNotifier::remove_all_callbacks()
 {
     m_callbacks.clear();
-    m_have_callbacks = false;
 }
 
 void CollectionNotifier::unregister() noexcept
@@ -301,8 +290,8 @@ bool CollectionNotifier::deliver(Realm& realm, SharedGroup& sg, std::exception_p
 
 void CollectionNotifier::call_callbacks()
 {
-    while (auto fn = next_callback()) {
-        fn(m_changes_to_deliver, m_error);
+    for (auto &callback : m_callbacks) {
+        callback.fn(m_changes_to_deliver, m_error);
     }
 
     if (m_error) {
@@ -313,23 +302,6 @@ void CollectionNotifier::call_callbacks()
     }
 }
 
-CollectionChangeCallback CollectionNotifier::next_callback()
-{
-    std::lock_guard<std::mutex> callback_lock(m_callback_mutex);
-
-    for (++m_callback_index; m_callback_index < m_callbacks.size(); ++m_callback_index) {
-        auto& callback = m_callbacks[m_callback_index];
-        if (!m_error && callback.initial_delivered && m_changes_to_deliver.empty()) {
-            continue;
-        }
-        callback.initial_delivered = true;
-        return callback.fn;
-    }
-
-    m_callback_index = npos;
-    return nullptr;
-}
-
 void CollectionNotifier::attach_to(SharedGroup& sg)
 {
     REALM_ASSERT(!m_sg);
diff --git a/src/object-store/src/impl/collection_notifier.hpp b/src/object-store/src/impl/collection_notifier.hpp
index 97699cdb..29988eef 100644
--- a/src/object-store/src/impl/collection_notifier.hpp
+++ b/src/object-store/src/impl/collection_notifier.hpp
@@ -152,7 +152,7 @@ public:
     bool deliver(Realm&, SharedGroup&, std::exception_ptr);
 
 protected:
-    bool have_callbacks() const noexcept { return m_have_callbacks; }
+    bool have_callbacks() const noexcept { return m_callbacks.size() > 0; }
     void add_changes(CollectionChangeBuilder change) { m_accumulated_changes.merge(std::move(change)); }
     void set_table(Table const& table);
     std::unique_lock<std::mutex> lock_target();
@@ -188,18 +188,6 @@ private:
     // while doing anything with them or m_callback_index
     std::mutex m_callback_mutex;
     std::vector<Callback> m_callbacks;
-
-    // Cached value for if m_callbacks is empty, needed to avoid deadlocks in
-    // run() due to lock-order inversion between m_callback_mutex and m_target_mutex
-    // It's okay if this value is stale as at worst it'll result in us doing
-    // some extra work.
-    std::atomic<bool> m_have_callbacks = {false};
-
-    // Iteration variable for looping over callbacks
-    // remove_callback() updates this when needed
-    size_t m_callback_index = npos;
-
-    CollectionChangeCallback next_callback();
 };
 
 } // namespace _impl