The Variant class is now meant to be used on the stack instead of allocated on the heap. As a result (and because of related changes), performance of Channels has roughly doubled when pushing and popping most types.

src/modules/thread/Channel.cpp

@@ -88,12 +88,6 @@ Channel::Channel(const std::string &name)
 
 Channel::~Channel()
 {
-	while (!queue.empty())
-	{
-		queue.front()->release();
-		queue.pop();
-	}
-
 	delete mutex;
 	delete cond;
 
@@ -101,13 +95,9 @@ Channel::~Channel()
 		namedChannels.erase(name);
 }
 
-unsigned long Channel::push(Variant *var)
+unsigned long Channel::push(const Variant &var)
 {
-	if (!var)
-		return 0;
-
 	Lock l(mutex);
-	var->retain();
 
 	// Keep a reference to ourselves
 	// if we're non-empty and named.
@@ -120,11 +110,8 @@ unsigned long Channel::push(Variant *var)
 	return ++sent;
 }
 
-void Channel::supply(Variant *var)
+void Channel::supply(const Variant &var)
 {
-	if (!var)
-		return;
-
 	Lock l(mutex);
 	unsigned long id = push(var);
 
@@ -132,13 +119,14 @@ void Channel::supply(Variant *var)
 		cond->wait(mutex);
 }
 
-Variant *Channel::pop()
+bool Channel::pop(Variant *var)
 {
 	Lock l(mutex);
-	if (queue.empty())
-		return 0;
 
-	Variant *var = queue.front();
+	if (queue.empty())
+		return false;
+
+	*var = queue.front();
 	queue.pop();
 
 	received++;
@@ -149,28 +137,26 @@ Variant *Channel::pop()
 	if (named && queue.empty())
 		release();
 
-	return var;
-} // NOTE: Returns a retained Variant
-
-Variant *Channel::demand()
-{
-	Variant *var;
-	Lock l(mutex);
-	while (!(var = pop()))
-		cond->wait(mutex);
-
-	return var;
+	return true;
 }
 
-Variant *Channel::peek()
+void Channel::demand(Variant *var)
 {
 	Lock l(mutex);
-	if (queue.empty())
-		return 0;
 
-	Variant *var = queue.front();
-	var->retain();
-	return var;
+	while (!pop(var))
+		cond->wait(mutex);
+}
+
+bool Channel::peek(Variant *var)
+{
+	Lock l(mutex);
+
+	if (queue.empty())
+		return false;
+
+	*var = queue.front();
+	return true;
 }
 
 int Channel::getCount()
@@ -188,10 +174,7 @@ void Channel::clear()
 		return;
 
 	while (!queue.empty())
-	{
-		queue.front()->release();
 		queue.pop();
-	}
 
 	// Finish all the supply waits
 	received = sent;

src/modules/thread/Channel.h

@@ -37,8 +37,6 @@ namespace thread
 class Channel : public love::Object
 {
 // FOR WRAPPER USE ONLY
-friend void retainVariant(Channel *, Variant *);
-friend void releaseVariant(Channel *, Variant *);
 friend int w_Channel_performAtomic(lua_State *);
 
 public:
@@ -48,11 +46,11 @@ public:
 
 	static Channel *getChannel(const std::string &name);
 
-	unsigned long push(Variant *var);
-	void supply(Variant *var); // blocking push
-	Variant *pop();
-	Variant *demand(); // blocking pop
-	Variant *peek();
+	unsigned long push(const Variant &var);
+	void supply(const Variant &var); // blocking push
+	bool pop(Variant *var);
+	void demand(Variant *var); // blocking pop
+	bool peek(Variant *var);
 	int getCount();
 	void clear();
 
@@ -67,7 +65,7 @@ private:
 
 	Mutex *mutex;
 	Conditional *cond;
-	std::queue<Variant *> queue;
+	std::queue<Variant> queue;
 	bool named;
 	std::string name;
 

src/modules/thread/LuaThread.cpp

@@ -33,18 +33,12 @@ namespace thread
 LuaThread::LuaThread(const std::string &name, love::Data *code)
 	: code(code)
 	, name(name)
-	, args(nullptr)
-	, nargs(0)
 {
 	threadName = name;
 }
 
 LuaThread::~LuaThread()
 {
-	// No args should still exist at this point,
-	// but you never know.
-	for (int i = 0; i < nargs; ++i)
-		args[i]->release();
 }
 
 void LuaThread::threadFunction()
@@ -74,16 +68,12 @@ void LuaThread::threadFunction()
 		error = luax_tostring(L, -1);
 	else
 	{
-		int pushedargs = nargs;
-		for (int i = 0; i < nargs; ++i)
-		{
-			args[i]->toLua(L);
-			args[i]->release();
-		}
-		// Set both args and nargs to nil, prevents the deconstructor from
-		// accessing it again.
-		nargs = 0;
-		args = nullptr;
+		int pushedargs = (int) args.size();
+
+		for (int i = 0; i < pushedargs; i++)
+			args[i].toLua(L);
+
+		args.clear();
 
 		if (lua_pcall(L, pushedargs, 0, 0) != 0)
 			error = luax_tostring(L, -1);
@@ -97,14 +87,9 @@ void LuaThread::threadFunction()
 	this->release();
 }
 
-bool LuaThread::start(Variant **args, int nargs)
+bool LuaThread::start(const std::vector<Variant> &args)
 {
-	for (int i = 0; i < this->nargs; ++i)
-		this->args[i]->release();
-
 	this->args = args;
-	this->nargs = nargs;
-
 	return Threadable::start();
 }
 
@@ -126,16 +111,12 @@ void LuaThread::onError()
 	p.type = THREAD_THREAD_ID;
 	p.object = this;
 
-	std::vector<StrongRef<Variant>> vargs = {
-		new Variant(THREAD_THREAD_ID, &p),
-		new Variant(error.c_str(), error.length())
+	std::vector<Variant> vargs = {
+		Variant(p.type, &p),
+		Variant(error.c_str(), error.length())
 	};
 
 	event::Message *msg = new event::Message("threaderror", vargs);
-
-	for (const StrongRef<Variant> &v : vargs)
-		v->release();
-
 	eventmodule->push(msg);
 	msg->release();
 }

src/modules/thread/LuaThread.h

@@ -23,6 +23,7 @@
 
 // STL
 #include <string>
+#include <vector>
 
 // LOVE
 #include "common/Data.h"
@@ -44,7 +45,7 @@ public:
 	void threadFunction();
 	const std::string &getError() const;
 
-	bool start(Variant **args, int nargs);
+	bool start(const std::vector<Variant> &args);
 
 private:
 
@@ -54,8 +55,7 @@ private:
 	std::string name;
 	std::string error;
 
-	Variant **args;
-	int nargs;
+	std::vector<Variant> args;
 
 }; // LuaThread
 

src/modules/thread/wrap_Channel.cpp

@@ -25,20 +25,6 @@ namespace love
 namespace thread
 {
 
-void retainVariant(Channel *c, Variant *v)
-{
-	c->lockMutex();
-	v->retain();
-	c->unlockMutex();
-}
-
-void releaseVariant(Channel *c, Variant *v)
-{
-	c->lockMutex();
-	v->release();
-	c->unlockMutex();
-}
-
 Channel *luax_checkchannel(lua_State *L, int idx)
 {
 	return luax_checktype<Channel>(L, idx, THREAD_CHANNEL_ID);
@@ -47,34 +33,29 @@ Channel *luax_checkchannel(lua_State *L, int idx)
 int w_Channel_push(lua_State *L)
 {
 	Channel *c = luax_checkchannel(L, 1);
-	Variant *var = lua_isnoneornil(L, 2) ? 0 : Variant::fromLua(L, 2);
-	if (!var)
+	Variant var;
+	if (!Variant::fromLua(L, 2, &var))
 		return luaL_argerror(L, 2, "boolean, number, string, love type, or flat table expected");
 	c->push(var);
-	releaseVariant(c, var);
 	return 0;
 }
 
 int w_Channel_supply(lua_State *L)
 {
 	Channel *c = luax_checkchannel(L, 1);
-	Variant *var = lua_isnoneornil(L, 2) ? 0 : Variant::fromLua(L, 2);
-	if (!var)
+	Variant var;
+	if (!Variant::fromLua(L, 2, &var))
 		return luaL_argerror(L, 2, "boolean, number, string, love type, or flat table expected");
 	c->supply(var);
-	releaseVariant(c, var);
 	return 0;
 }
 
 int w_Channel_pop(lua_State *L)
 {
 	Channel *c = luax_checkchannel(L, 1);
-	Variant *var = c->pop();
-	if (var)
-	{
-		var->toLua(L);
-		releaseVariant(c, var);
-	}
+	Variant var;
+	if (c->pop(&var))
+		var.toLua(L);
 	else
 		lua_pushnil(L);
 	return 1;
@@ -83,21 +64,18 @@ int w_Channel_pop(lua_State *L)
 int w_Channel_demand(lua_State *L)
 {
 	Channel *c = luax_checkchannel(L, 1);
-	Variant *var = c->demand();
-	var->toLua(L);
-	releaseVariant(c, var);
+	Variant var;
+	c->demand(&var);
+	var.toLua(L);
 	return 1;
 }
 
 int w_Channel_peek(lua_State *L)
 {
 	Channel *c = luax_checkchannel(L, 1);
-	Variant *var = c->peek();
-	if (var)
-	{
-		var->toLua(L);
-		releaseVariant(c, var);
-	}
+	Variant var;
+	if (c->peek(&var))
+		var.toLua(L);
 	else
 		lua_pushnil(L);
 	return 1;

src/modules/thread/wrap_LuaThread.cpp

@@ -33,26 +33,22 @@ LuaThread *luax_checkthread(lua_State *L, int idx)
 int w_Thread_start(lua_State *L)
 {
 	LuaThread *t = luax_checkthread(L, 1);
+	std::vector<Variant> args;
 	int nargs = lua_gettop(L) - 1;
-	Variant **args = 0;
 
-	if (nargs > 0)
+	Variant v;
+	for (int i = 0; i < nargs; ++i)
 	{
-		args = new Variant*[nargs];
-		for (int i = 0; i < nargs; ++i)
+		if (!Variant::fromLua(L, i+2, &v))
 		{
-			args[i] = Variant::fromLua(L, i+2);
-			if (!args[i])
-			{
-				for (int j = i; j >= 0; j--)
-					delete args[j];
-				delete[] args;
-				return luaL_argerror(L, i+2, "boolean, number, string, love type, or flat table expected");
-			}
+			args.clear();
+			return luaL_argerror(L, i+2, "boolean, number, string, love type, or flat table expected");
 		}
+
+		args.push_back(v);
 	}
 
-	luax_pushboolean(L, t->start(args, nargs));
+	luax_pushboolean(L, t->start(args));
 	return 1;
 }