Preserve Messaging token until a Listener is set (#1634)

* Preserve Messaging token until a Listener is set * Format file

Author: a-maurice

messaging/src/common.cc

@@ -48,6 +48,8 @@ static Listener* g_listener = nullptr;
 
 // Keep track of the most recent token received.
 static std::string* g_prev_token_received = nullptr;
+// Keep track if that token was receieved without a listener set.
+staticbool g_has_pending_token = false;
 
 namespaceinternal {
 
@@ -91,11 +93,18 @@ Listener* SetListener(Listener* listener) {
  g_prev_token_received = new std::string;
  }
  g_listener = listener;
+// If we have a pending token, send it before notifying other systems about
+// the listener.
+if (g_listener && g_has_pending_token && g_prev_token_received) {
+ g_listener->OnTokenReceived(g_prev_token_received->c_str());
+ g_has_pending_token = false;
+ }
 NotifyListenerSet(listener);
 if (!listener && g_prev_token_received) {
  std::string* ptr = g_prev_token_received;
  g_prev_token_received = nullptr;
 delete ptr;
+ g_has_pending_token = false;
  }
 return previous_listener;
 }
@@ -119,13 +128,20 @@ void NotifyListenerOnTokenReceived(const char* token) {
  MutexLock lock(g_listener_lock);
 // If we have a previous token that we've notified any listener about, check
 // to ensure no repeat.
-if (g_prev_token_received) {
-if (*g_prev_token_received == token) {
-return;
- }
- *g_prev_token_received = token;
+if (g_prev_token_received && *g_prev_token_received == token) {
+return;
+ }
+
+if (!g_prev_token_received) g_prev_token_received = new std::string;
+ *g_prev_token_received = token;
+
+if (g_listener) {
+ g_listener->OnTokenReceived(token);
+ } else {
+// Set so that if a listener is set in the future, it will be sent
+// the token, since the underlying platform won't send it again.
+ g_has_pending_token = true;
  }
-if (g_listener) g_listener->OnTokenReceived(token);
 }
 
 classPollableListenerImpl {

release_build_files/readme.md

@@ -631,6 +631,11 @@ workflow use only during the development of your app, not for publicly shipping
 code.
 
 ## Release Notes
+### Upcoming Release
+- Changes
+- Messaging: Changed SetListener to send the last token received
+ before the listener was set.
+
 ### 12.2.0
 - Changes
 - General (iOS): Update to Firebase Cocoapods version 11.0.0.