From 5f92c76c31eb93bd86780f1d70db2081f19dac1e Mon Sep 17 00:00:00 2001
From: Lars Melchior <TheLartians@users.noreply.github.com>
Date: Mon, 22 Apr 2019 21:34:39 +0200
Subject: [PATCH] Data handling (#11)

* move data into shared_ptr

* v2.0.2

* remove default constructor

* fix move constructor

* reset when observing new event
---
 CMakeLists.txt       |  2 +-
 README.md            |  2 +-
 include/lars/event.h | 80 +++++++++++++++++++-------------------------
 3 files changed, 36 insertions(+), 48 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ded2841..52c8721 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,7 +3,7 @@ cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
 # ---- Project ----
 
 project(LarsEvent 
-  VERSION 2.0.1
+  VERSION 2.0.2
   LANGUAGES CXX
 )
 
diff --git a/README.md b/README.md
index 72d566e..afbe130 100644
--- a/README.md
+++ b/README.md
@@ -36,7 +36,7 @@ With [CPM](https://github.com/TheLartians/CPM), lars::Event can be added to your
 ```cmake
 CPMAddPackage(
   NAME LarsEvent
-  VERSION 2.0.1
+  VERSION 2.0.2
   GIT_REPOSITORY https://github.com/TheLartians/Event.git
 )
 
diff --git a/include/lars/event.h b/include/lars/event.h
index 85e90a0..2484ea6 100644
--- a/include/lars/event.h
+++ b/include/lars/event.h
@@ -49,35 +49,29 @@ namespace lars{
     };
 
     using HandlerList = std::vector<StoredHandler>;
-    using EventPointer = std::shared_ptr<const Event *>;
-    using WeakEventPointer = std::weak_ptr<const Event *>;
     
-    mutable HandlerID IDCounter = 0;
-    mutable HandlerList observers;
-    mutable std::mutex observerMutex;
-    EventPointer self;
+    struct Data {
+      HandlerID IDCounter = 0;
+      HandlerList observers;
+      std::mutex observerMutex;
+    };
+
+    std::shared_ptr<Data> data;
 
     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); }
+      std::lock_guard<std::mutex> lock(data->observerMutex);
+      data->observers.emplace_back(StoredHandler{data->IDCounter,h});
+      return data->IDCounter++;
     }
-    
+        
   public:
     
     struct Observer:public lars::Observer::Base{
-      WeakEventPointer parent;
+      std::weak_ptr<Data> data;
       HandlerID id;
       
       Observer(){}
-      Observer(const EventPointer & _parent, HandlerID _id):parent(_parent), id(_id){
-      }
+      Observer(const std::weak_ptr<Data> &_data, HandlerID _id):data(_data), id(_id){}
       
       Observer(Observer &&other) = default;
       Observer(const Observer &other) = delete;
@@ -86,50 +80,44 @@ namespace lars{
       Observer & operator=(Observer &&other)=default;
       
       void observe(const Event &event, const Handler &handler){
+        reset();
         *this = event.createObserver(handler);
       }
 
       void reset(){
-        if(auto p = parent.lock()){ 
-          (*p)->eraseHandler(id); 
+        if(auto d = data.lock()){ 
+          std::lock_guard<std::mutex> lock(d->observerMutex);
+          auto it = std::find_if(d->observers.begin(), d->observers.end(), [&](auto &o){ return o.id == id; });
+          if (it != d->observers.end()) { d->observers.erase(it); }
         }
-        parent.reset();
+        data.reset();
       }
       
       ~Observer(){ reset(); }
     };
     
-    Event():self(std::make_shared<const Event *>(this)){
-      
+    Event():data(std::make_shared<Data>()){
     }
-    
-    Event(const Event &) = delete;
-
-    Event(Event &&other){
-      *this = std::move(other);
-    }
-    
-    Event & operator=(const Event &) = delete;
 
-    Event & operator=(Event &&other){
-      self = std::move(other.self);
-      *self = this;
-      observers = std::move(other.observers);
-      IDCounter = other.IDCounter;
+    Event(const Event &) = delete;
+    Event(Event &&other):Event(){ *this = std::move(other); }
+    Event &operator=(const Event &) = delete;
+    Event &operator=(Event &&other){
+      std::swap(data, other.data);
       return *this;
     }
-    
+
     void emit(Args ... args) const {
-      observerMutex.lock();
-      auto tmpObservers = observers;
-      observerMutex.unlock();
+      data->observerMutex.lock();
+      auto tmpObservers = data->observers;
+      data->observerMutex.unlock();
       for(auto &observer: tmpObservers){
         observer.callback(args...);
       }
     }
     
     Observer createObserver(const Handler &h)const{
-      return Observer(self, addHandler(h));
+      return Observer(data, addHandler(h));
     }
     
     void connect(const Handler &h)const{
@@ -137,13 +125,13 @@ namespace lars{
     }
     
     void clearObservers(){
-      std::lock_guard<std::mutex> lock(observerMutex);
-      observers.clear();
+      std::lock_guard<std::mutex> lock(data->observerMutex);
+      data->observers.clear();
     }
     
     size_t observerCount() const {
-      std::lock_guard<std::mutex> lock(observerMutex);
-      return observers.size();
+      std::lock_guard<std::mutex> lock(data->observerMutex);
+      return data->observers.size();
     }
 
   };