fix mod dynlib lifetime issues

libswan/include/swan/Mod.h

@@ -11,13 +11,19 @@
 #include "WorldGen.h"
 #include "Entity.h"
 #include "Resource.h"
+#include "OS.h"
 #include "util.h"
 
 namespace Swan {
 
 class Mod {
 public:
-	Mod(const std::string &path): path_(path) {}
+	Mod(const std::string &path, OS::Dynlib &&dynlib):
+		path_(path), dynlib_(std::move(dynlib)) {}
+
+	// We have to manually ensure anything created from the dynlib
+	// is destructed before the dynlib itself is destructed
+	~Mod();
 
 	void init(const std::string &name);
 
@@ -43,6 +49,7 @@ private:
 	std::vector<std::unique_ptr<Entity::Factory>> entities_;
 
 	std::string path_;
+	OS::Dynlib dynlib_;
 	bool inited_ = false;
 };
 

libswan/include/swan/OS.h

@@ -12,6 +12,8 @@ bool isTTY(FILE *f);
 class Dynlib {
 public:
 	Dynlib(const std::string &path);
+	Dynlib(const Dynlib &) = delete;
+	Dynlib(Dynlib &&dl);
 	~Dynlib();
 
 	template<typename T> T get(const std::string &name) { return (T)getVoid(name); }

libswan/src/Game.cc

@@ -13,14 +13,13 @@ namespace Swan {
 
 std::unique_ptr<Mod> Game::loadMod(const std::string &path) {
 	OS::Dynlib dl(path + "/mod");
-
 	auto init = dl.get<void (*)(Swan::Mod &)>("mod_init");
 	if (init == NULL) {
 		warn << path << ": No 'mod_init' function!";
-		return NULL;
+		return nullptr;
 	}
 
-	std::unique_ptr<Mod> mod = std::make_unique<Mod>(path);
+	std::unique_ptr<Mod> mod = std::make_unique<Mod>(path, std::move(dl));
 	init(*mod);
 	return mod;
 }

libswan/src/Mod.cc

@@ -8,6 +8,14 @@
 
 namespace Swan {
 
+Mod::~Mod() {
+	images_.clear();
+	tiles_.clear();
+	items_.clear();
+	worldgens_.clear();
+	entities_.clear();
+}
+
 void Mod::init(const std::string &name) {
 	name_ = name;
 	inited_ = true;

libswan/src/OS.cc

@@ -16,13 +16,19 @@ bool isTTY(FILE *f) {
 
 Dynlib::Dynlib(const std::string &path) {
 	handle_ = dlopen((path + ".so").c_str(), RTLD_LAZY);
-	if (handle_ == NULL) {
+	if (handle_ == nullptr) {
 		throw std::runtime_error(dlerror());
 	}
 }
 
+Dynlib::Dynlib(Dynlib &&dl) {
+	handle_ = dl.handle_;
+	dl.handle_ = nullptr;
+}
+
 Dynlib::~Dynlib() {
-	dlclose(handle_);
+	if (handle_ != nullptr)
+		dlclose(handle_);
 }
 
 void *Dynlib::getVoid(const std::string &name) {