Work on making Angelscript work threaded

src/ScriptResolving/AngelScript/AngelScriptResolver.cpp

@@ -98,6 +98,8 @@ void AngelScriptResolver::Initialize(CreatureLib::Battling::BattleLibrary* arg,
     }
 
     _contextPool = new ContextPool(_engine);
+
+    asPrepareMultithread();
 }
 
 void AngelScriptResolver::RegisterTypes() {

src/ScriptResolving/AngelScript/ContextPool.hpp

@@ -2,34 +2,61 @@
 #define PKMNLIB_CONTEXTPOOL_HPP
 
 #include <angelscript.h>
+#include <mutex>
+#include <thread>
 
 class ContextPool {
-    std::vector<asIScriptContext*> _pool;
+    struct CtxThreadedPoolStorage {
+        std::vector<asIScriptContext*> Pool;
+        std::mutex Lock;
+
+        ~CtxThreadedPoolStorage() {
+            for (auto* ctx : Pool) {
+                ctx->Release();
+            }
+        }
+    };
+
+    ArbUt::Dictionary<std::thread::id, CtxThreadedPoolStorage*> _pool;
     asIScriptEngine* _engine;
 
+    CtxThreadedPoolStorage* GetThreadPool() {
+        auto id = std::this_thread::get_id();
+        if (!_pool.Has(id)) {
+            auto t = CtxThreadedPoolStorage();
+            _pool.Insert(id, new CtxThreadedPoolStorage());
+        }
+        return _pool[id];
+    }
+
 public:
     ContextPool(asIScriptEngine* engine) : _engine(engine) {}
 
     ~ContextPool() {
-        for (auto ctx : _pool) {
-            ctx->Release();
+        for (const auto& kv : _pool) {
+            delete kv.second;
         }
     }
 
     asIScriptContext* RequestContext() {
         // Get a context from the pool, or create a new
         asIScriptContext* ctx = nullptr;
-        if (!_pool.empty()) {
-            ctx = *_pool.rbegin();
-            _pool.pop_back();
-        } else
+        auto* pool = GetThreadPool();
+        std::lock_guard<std::mutex> guard(pool->Lock);
+        if (!pool->Pool.empty()) {
+            ctx = *pool->Pool.rbegin();
+            pool->Pool.pop_back();
+        } else {
             ctx = _engine->CreateContext();
+        }
         return ctx;
     }
 
     void ReturnContextToPool(asIScriptContext* ctx) {
         ctx->Unprepare();
-        _pool.push_back(ctx);
+        auto* pool = GetThreadPool();
+        std::lock_guard<std::mutex> guard(pool->Lock);
+        pool->Pool.push_back(ctx);
     }
 };