bluetooth: {start,stop}Notifications() return the characteristic

third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTCharacteristic.cpp

Index: third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTCharacteristic.cpp
diff --git a/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTCharacteristic.cpp b/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTCharacteristic.cpp
index b0ec4cd4b83d32eaf271d801427356099afb4460..f03da6bb72ebf2914cb120e89ebb715d576df450 100644
--- a/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTCharacteristic.cpp
+++ b/third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTCharacteristic.cpp
@@ -195,12 +195,36 @@ ScriptPromise BluetoothRemoteGATTCharacteristic::writeValue(ScriptState* scriptS
     return promise;
 }
 
+class NotificationsCallback : public WebBluetoothNotificationsCallbacks {
+public:
+    NotificationsCallback(BluetoothRemoteGATTCharacteristic* characteristic, ScriptPromiseResolver* resolver) : m_webCharacteristic(characteristic), m_resolver(resolver) {}
+
+    void onSuccess() override
+    {
+        if (!m_resolver->getExecutionContext() || m_resolver->getExecutionContext()->activeDOMObjectsAreStopped())
+            return;
+
+        m_resolver->resolve(m_webCharacteristic);
+    }
+
+    void onError(int32_t error /* Corresponds to WebBluetoothError in web_bluetooth.mojom */) override
+    {
+        if (!m_resolver->getExecutionContext() || m_resolver->getExecutionContext()->activeDOMObjectsAreStopped())
+            return;
+        m_resolver->reject(BluetoothError::take(m_resolver, error));
+    }
+
+private:
+    WeakPersistent<BluetoothRemoteGATTCharacteristic> m_webCharacteristic;

[ortuno, 2016/08/05 01:43:44]

This needs to be Persistent. Otherwise you might resolve the promise with null.

[haraken, 2016/08/05 04:27:58]

Are you sure that the persistents don't create a cycle? i.e., is it guaranteed
that onSuccess or onError is called in a finite time period?

[ortuno, 2016/08/05 14:35:38]

Yes, it's guaranteed. If we don't ever call onSuccess or onError then it's a bug
on our mojo service.

+    Persistent<ScriptPromiseResolver> m_resolver;
+};
+
 ScriptPromise BluetoothRemoteGATTCharacteristic::startNotifications(ScriptState* scriptState)
 {
     WebBluetooth* webbluetooth = BluetoothSupplement::fromScriptState(scriptState);
     ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
-    webbluetooth->startNotifications(m_webCharacteristic->characteristicInstanceID, new CallbackPromiseAdapter<void, BluetoothError>(resolver));
+    webbluetooth->startNotifications(m_webCharacteristic->characteristicInstanceID, new NotificationsCallback(this, resolver));
     return promise;
 }
 
@@ -217,7 +241,7 @@ ScriptPromise BluetoothRemoteGATTCharacteristic::stopNotifications(ScriptState*
     WebBluetooth* webbluetooth = BluetoothSupplement::fromScriptState(scriptState);
     ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
-    webbluetooth->stopNotifications(m_webCharacteristic->characteristicInstanceID, new CallbackPromiseAdapter<void, BluetoothError>(resolver));
+    webbluetooth->stopNotifications(m_webCharacteristic->characteristicInstanceID, new NotificationsCallback(this, resolver));
     return promise;
 }