From 208bb097dd4490e0852ff5b34bbd5ce714b5c44d Mon Sep 17 00:00:00 2001
From: Deukhoofd <Deukhoofd@gmail.com>
Date: Fri, 7 Aug 2020 12:20:59 +0200
Subject: [PATCH] Make event listeners threaded.

Signed-off-by: Deukhoofd <Deukhoofd@gmail.com>
---
 CMakeLists.txt                        |  5 +++-
 src/Battling/EventHooks/EventHook.hpp | 33 ++++++++++++++++++++++++---
 src/Battling/Models/Battle.cpp        |  1 +
 tests/BattleTests/EventHookTests.cpp  |  2 ++
 4 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7c794db..e70db46 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,6 +14,9 @@ option(STATICC "Whether gcc and stdc++ should be linked statically to the librar
 include(CmakeConanSetup.cmake)
 SetupConan()
 
+set(THREADS_PREFER_PTHREAD_FLAG ON)
+find_package(Threads REQUIRED)
+
 # Set whether we want a static or shared library.
 set(LIBTYPE STATIC)
 if (SHARED)
@@ -44,7 +47,7 @@ if (STATICC)
 endif ()
 
 # And link the libraries together
-target_link_libraries(CreatureLib PUBLIC ${_LIBRARYLINKS})
+target_link_libraries(CreatureLib PUBLIC ${_LIBRARYLINKS} Threads::Threads)
 
 if (TESTS)
     # Create Test executable
diff --git a/src/Battling/EventHooks/EventHook.hpp b/src/Battling/EventHooks/EventHook.hpp
index 10be88b..59628a2 100644
--- a/src/Battling/EventHooks/EventHook.hpp
+++ b/src/Battling/EventHooks/EventHook.hpp
@@ -2,6 +2,7 @@
 #define CREATURELIB_EVENTHOOK_HPP
 
 #include <functional>
+#include <thread>
 #include <vector>
 #include "../../Library/Exceptions/CreatureException.hpp"
 #include "EventData.hpp"
@@ -18,6 +19,7 @@ namespace CreatureLib::Battling {
         size_t _offset;
         size_t _capacity;
         uint8_t* _memory = nullptr;
+        std::thread* _currentThread = nullptr;
 
         static constexpr size_t initialSize = 2048;
         static constexpr size_t stepSize = 1024;
@@ -33,7 +35,14 @@ namespace CreatureLib::Battling {
         EventHook(const EventHook&) = delete;
         EventHook& operator=(const EventHook&) = delete;
 
-        ~EventHook() { free(_memory); }
+        ~EventHook() {
+            free(_memory);
+            if (_currentThread != nullptr && _currentThread->joinable()) {
+                _currentThread->join();
+                delete _currentThread;
+                _currentThread = nullptr;
+            }
+        }
 
         size_t GetPosition() const noexcept { return _offset; }
         size_t GetCapacity() const noexcept { return _capacity; }
@@ -41,6 +50,11 @@ namespace CreatureLib::Battling {
         template <class T, class... parameters> void Trigger(parameters... args) {
             if (_listeners.size() == 0)
                 return;
+            if (_currentThread != nullptr && _currentThread->joinable()) {
+                _currentThread->join();
+                delete _currentThread;
+                _currentThread = nullptr;
+            }
             if (_offset + sizeof(T) >= _capacity) {
                 _capacity += stepSize;
                 auto newPtr = realloc(_memory, _capacity);
@@ -52,12 +66,25 @@ namespace CreatureLib::Battling {
             uint8_t* ptr = _memory + _offset;
             T* event = new (ptr) T(args...);
             _offset += sizeof(T);
+            _currentThread = new std::thread(&EventHook::RunListeners, this, event);
+        }
+
+        void RegisterListener(const EventHookFunc& func) { _listeners.push_back(func); }
+
+        void FinishListening() {
+            if (_currentThread != nullptr && _currentThread->joinable()) {
+                _currentThread->join();
+                delete _currentThread;
+                _currentThread = nullptr;
+            }
+        }
+
+    private:
+        void RunListeners(EventData* event) {
             for (auto listener : _listeners) {
                 try_creature(listener(event), "Exception in event listener");
             }
         }
-
-        void RegisterListener(const EventHookFunc& func) { _listeners.push_back(func); }
     };
 }
 #endif // CREATURELIB_EVENTHOOK_HPP
diff --git a/src/Battling/Models/Battle.cpp b/src/Battling/Models/Battle.cpp
index dfa8c9b..3e310f7 100644
--- a/src/Battling/Models/Battle.cpp
+++ b/src/Battling/Models/Battle.cpp
@@ -89,6 +89,7 @@ void Battle::CheckChoicesSetAndRun() {
         this->_currentTurnQueue = nullptr;
     }
     TriggerEventListener<TurnEndEvent>();
+    _eventHook.FinishListening();
 }
 
 ArbUt::BorrowedPtr<ChoiceQueue> Battle::GetCurrentTurnQueue() const noexcept { return _currentTurnQueue; }
diff --git a/tests/BattleTests/EventHookTests.cpp b/tests/BattleTests/EventHookTests.cpp
index 1568cfe..668f091 100644
--- a/tests/BattleTests/EventHookTests.cpp
+++ b/tests/BattleTests/EventHookTests.cpp
@@ -13,6 +13,7 @@ TEST_CASE("Build and use event hook", "[Battling]") {
     for (size_t i = 0; i < 10; i++) {
         eventHook.Trigger<DamageEvent>(nullptr, DamageSource::AttackDamage, 0, 0);
     }
+    eventHook.FinishListening();
     REQUIRE(events.size() == 10);
     REQUIRE(events[0]->GetKind() == EventDataKind::Damage);
 }
@@ -24,6 +25,7 @@ TEST_CASE("Build and use event hook a lot", "[Battling]") {
     for (size_t i = 0; i < 10000; i++) {
         eventHook.Trigger<DamageEvent>(nullptr, DamageSource::AttackDamage, 0, 0);
     }
+    eventHook.FinishListening();
     REQUIRE(events.size() == 10000);
 }