add remove/add during commit tests

Author: TheLartians

include/lars/event.h

@@ -4,6 +4,7 @@
 #include <memory>
 #include <vector>
 #include <utility>
+#include <mutex>
 
 namespace lars{
 
@@ -53,18 +54,19 @@ namespace lars{
 
     mutable HandlerID IDCounter = 0;
     mutable HandlerList observers;
+    mutable std::mutex observerMutex;
     EventPointer self;
 
     HandlerID addHandler(Handler h)const{
+      std::lock_guard<std::mutex> lock(observerMutex);
       observers.emplace_back(StoredHandler{IDCounter,h});
       return IDCounter++;
     }
 
     void eraseHandler(const HandlerID &id)const{
+      std::lock_guard<std::mutex> lock(observerMutex);
       auto it = std::find_if(observers.begin(), observers.end(), [&](auto &o){ return o.id == id; });
-      if (it != observers.end()) {
-        observers.erase(it);
-      }
+      if (it != observers.end()) { observers.erase(it); }
     }
 
   public:
@@ -118,12 +120,11 @@ namespace lars{
     }
 
     void emit(Args ... args) const {
-      for(auto it = observers.begin();it != observers.end();){
-        auto &f = *it;
-        auto next = it;
-        ++next;
-        f.callback(args...);
-        it = next;
+      observerMutex.lock();
+      auto tmpObservers = observers;
+      observerMutex.unlock();
+      for(auto &observer: tmpObservers){
+        observer.callback(args...);
       }
     }
 
@@ -136,10 +137,12 @@ namespace lars{
     }
 
     void clearObservers(){
+      std::lock_guard<std::mutex> lock(observerMutex);
       observers.clear();
     }
 
     size_t observerCount() const {
+      std::lock_guard<std::mutex> lock(observerMutex);
       return observers.size();
     }
 

include/lars/observable_value.h

@@ -5,8 +5,6 @@
 #include <type_traits>
 #include <utility>
 
-#include <iostream>
-
 namespace lars {
 
   template <class T> class ObservableValue {
@@ -54,7 +52,7 @@ namespace lars {
       const ObservableValue<D> & ... deps
     ): 
       ObservableValue<T>(handler(deps.get()...)),
-      observers(std::make_tuple(deps.onChange.createObserver([&,this](const auto &v){
+      observers(std::make_tuple(deps.onChange.createObserver([&,this](const auto &){
         this->set(handler(deps.get()...));
       })...))
     {

tests/CMakeLists.txt

@@ -48,8 +48,6 @@ if (${ENABLE_TEST_COVERAGE})
 
   if(NOT extra-cmake-modules_POPULATED)
     FetchContent_Populate(extra-cmake-modules)
-    message("test 1: ${extra-cmake-modules_SOURCE_DIR}")
-    message("test 2: ${extra-cmake-modules_POPULATED}")
     include(${extra-cmake-modules_SOURCE_DIR}/CodeCoverage.cmake)
   endif()
 

tests/event.cpp

@@ -55,7 +55,27 @@ TEST_CASE("Event"){
     }
   }
 
-  SECTION("scoped event"){
+  SECTION("removing observer during emit"){
+    lars::Event<> event;
+    lars::Event<>::Observer observer;
+    unsigned count = 0;
+    observer = event.createObserver([&](){ observer.reset(); count++; });
+    event.emit();
+    REQUIRE(count == 1);
+    event.emit();
+    REQUIRE(count == 1);
+  }
+
+  SECTION("adding observers during emit"){
+    lars::Event<> event;
+    std::function<void()> callback;
+    callback = [&](){ event.connect(callback); };
+    event.connect(callback);
+    REQUIRE(event.observerCount() == 1);
+    event.emit();
+    REQUIRE(event.observerCount() == 2);
+    event.emit();
+    REQUIRE(event.observerCount() == 4);
   }
 
   SECTION("emit data"){