Make Observer to be able to observe multiple Observables. (#1234)

* Make Observer to be able to observe multiple Observables.

* Fix Observer destructor cleanup.

Co-authored-by: Sacha Weatherstone <sachaw100@hotmail.com>

src/Observer.h

@@ -11,13 +11,13 @@ template <class T> class Observable;
  */
 template <class T> class Observer
 {
-    Observable<T> *observed = NULL;
+  std::list<Observable<T> *> observed;
 
   public:
     virtual ~Observer();
 
-    /// Stop watching our current obserable
-    void unobserve();
+    /// Stop watching the obserable
+    void unobserve(Observable<T> *o);
 
     /// Start watching a specified observable
     void observe(Observable<T> *o);
@@ -87,21 +87,21 @@ template <class T> class Observable
 
 template <class T> Observer<T>::~Observer()
 {
-    unobserve();
+    for (typename std::list<Observable<T> *>::const_iterator iterator = observed.begin(); iterator != observed.end();
+        ++iterator) {
+        (*iterator)->removeObserver(this);
+    }
+    observed.clear();
 }
 
-template <class T> void Observer<T>::unobserve()
+template <class T> void Observer<T>::unobserve(Observable<T> *o)
 {
-    if (observed)
-        observed->removeObserver(this);
-    observed = NULL;
+    o->removeObserver(this);
+    observed.remove(o);
 }
 
 template <class T> void Observer<T>::observe(Observable<T> *o)
 {
-    // We can only watch one thing at a time
-    assert(!observed);
-
-    observed = o;
+    observed.push_back(o);
     o->addObserver(this);
 }

src/gps/GPS.cpp

@@ -95,8 +95,8 @@ bool GPS::setup()
 GPS::~GPS()
 {
     // we really should unregister our sleep observer
-    notifySleepObserver.unobserve();
-    notifyDeepSleepObserver.unobserve();
+    notifySleepObserver.unobserve(&notifySleep);
+    notifyDeepSleepObserver.unobserve(&notifyDeepSleep);
 }
 
 bool GPS::hasLock() { return hasValidLocation; }

src/mesh/PhoneAPI.cpp

@@ -48,7 +48,7 @@ void PhoneAPI::close()
     if (state != STATE_SEND_NOTHING) {
         state = STATE_SEND_NOTHING;
 
-        unobserve();
+        unobserve(&service.fromNumChanged);
         releasePhonePacket(); // Don't leak phone packets on shutdown
 
         onConnectionChanged(false);