Proper LuaString <-> String handling

Null-terminator usage is opt-in

source/core/StarLua.cpp

@@ -115,6 +115,11 @@ LuaTable LuaContext::createTable() {
   return engine().createTable();
 }
 
+LuaNullEnforcer::LuaNullEnforcer(LuaEngine& engine)
+  : m_engine(&engine) { ++m_engine->m_nullTerminated; };
+
+LuaNullEnforcer::~LuaNullEnforcer() { --m_engine->m_nullTerminated; };
+
 LuaValue LuaConverter<Json>::from(LuaEngine& engine, Json const& v) {
   if (v.isType(Json::Type::Null)) {
     return LuaNil;
@@ -202,6 +207,7 @@ LuaEnginePtr LuaEngine::create(bool safe) {
   self->m_instructionCount = 0;
   self->m_recursionLevel = 0;
   self->m_recursionLimit = 0;
+  self->m_nullTerminated = 0;
 
   if (!self->m_state)
     throw LuaException("Failed to initialize Lua");
@@ -455,6 +461,9 @@ ByteArray LuaEngine::compile(ByteArray const& contents, String const& name) {
 LuaString LuaEngine::createString(String const& str) {
   lua_checkstack(m_state, 1);
 
+  if (m_nullTerminated)
+    lua_pushstring(m_state, str.utf8Ptr());
+  else
     lua_pushlstring(m_state, str.utf8Ptr(), str.utf8Size());
   return LuaString(LuaDetail::LuaHandle(RefPtr<LuaEngine>(this), popHandle(m_state)));
 }
@@ -543,6 +552,10 @@ size_t LuaEngine::memoryUsage() const {
   return (size_t)lua_gc(m_state, LUA_GCCOUNT, 0) * 1024 + lua_gc(m_state, LUA_GCCOUNTB, 0);
 }
 
+LuaNullEnforcer LuaEngine::nullTerminate() {
+  return LuaNullEnforcer(*this);
+}
+
 LuaEngine* LuaEngine::luaEnginePtr(lua_State* state) {
   return (*reinterpret_cast<LuaEngine**>(lua_getextraspace(state)));
 }
@@ -710,10 +723,34 @@ char const* LuaEngine::stringPtr(int handleIndex) {
 }
 
 size_t LuaEngine::stringLength(int handleIndex) {
+  if (m_nullTerminated)
+    return strlen(lua_tostring(m_handleThread, handleIndex));
+  else {
     size_t len = 0;
     lua_tolstring(m_handleThread, handleIndex, &len);
     return len;
   }
+}
+
+String LuaEngine::string(int handleIndex) {
+  if (m_nullTerminated)
+    return String(lua_tostring(m_handleThread, handleIndex));
+  else {
+    size_t len = 0;
+    const char* data = lua_tolstring(m_handleThread, handleIndex, &len);
+    return String(data, len);
+  }
+}
+
+StringView LuaEngine::stringView(int handleIndex) {
+  if (m_nullTerminated)
+    return StringView(lua_tostring(m_handleThread, handleIndex));
+  else {
+    size_t len = 0;
+    const char* data = lua_tolstring(m_handleThread, handleIndex, &len);
+    return StringView(data, len);
+  }
+}
 
 LuaValue LuaEngine::tableGet(bool raw, int handleIndex, LuaValue const& key) {
   lua_checkstack(m_state, 1);

source/core/StarLua.hpp

@@ -156,6 +156,7 @@ public:
   size_t length() const;
 
   String toString() const;
+  StringView view() const;
 };
 
 bool operator==(LuaString const& s1, LuaString const& s2);
@@ -383,6 +384,38 @@ public:
   LuaUserData createUserData(T t);
 };
 
+template <typename T>
+struct LuaNullTermWrapper : T {
+  LuaNullTermWrapper() : T() {}
+  LuaNullTermWrapper(LuaNullTermWrapper const& nt) : T(nt) {}
+  LuaNullTermWrapper(LuaNullTermWrapper&& nt) : T(std::move(nt)) {}
+  LuaNullTermWrapper(T const& bt) : T(bt) {}
+  LuaNullTermWrapper(T&& bt) : T(std::move(bt)) {}
+
+  LuaNullTermWrapper& operator=(LuaNullTermWrapper const& rhs) {
+    T::operator=(rhs);
+    return *this;
+  }
+
+  LuaNullTermWrapper& operator=(LuaNullTermWrapper&& rhs) {
+    T::operator=(std::move(rhs));
+    return *this;
+  }
+
+  LuaNullTermWrapper& operator=(T&& other) {
+    T::operator=(std::forward<T>(other));
+    return *this;
+  }
+};
+
+class LuaNullEnforcer {
+public:
+  LuaNullEnforcer(LuaEngine& engine);
+  ~LuaNullEnforcer();
+private:
+  LuaEngine* m_engine;
+};
+
 // Types that want to participate in automatic lua conversion should specialize
 // this template and provide static to and from methods on it.  The method
 // signatures will be called like:
@@ -565,6 +598,9 @@ public:
   // Bytes in use by lua
   size_t memoryUsage() const;
 
+  // Enforce null-terminated string conversion as long as the returned enforcer object is in scope.
+  LuaNullEnforcer nullTerminate();
+
 private:
   friend struct LuaDetail::LuaHandle;
   friend class LuaReference;
@@ -574,6 +610,7 @@ private:
   friend class LuaThread;
   friend class LuaUserData;
   friend class LuaContext;
+  friend class LuaNullEnforcer;
 
   LuaEngine() = default;
 
@@ -599,6 +636,8 @@ private:
 
   char const* stringPtr(int handleIndex);
   size_t stringLength(int handleIndex);
+  String string(int handleIndex);
+  StringView stringView(int handleIndex);
 
   LuaValue tableGet(bool raw, int handleIndex, LuaValue const& key);
   LuaValue tableGet(bool raw, int handleIndex, char const* key);
@@ -690,6 +729,7 @@ private:
   uint64_t m_instructionCount;
   unsigned m_recursionLevel;
   unsigned m_recursionLimit;
+  unsigned m_nullTerminated;
   HashMap<tuple<String, unsigned>, shared_ptr<LuaProfileEntry>> m_profileEntries;
 };
 
@@ -796,7 +836,7 @@ struct LuaConverter<String> {
 
   static Maybe<String> to(LuaEngine&, LuaValue const& v) {
     if (v.is<LuaString>())
-      return String(v.get<LuaString>().ptr());
+      return v.get<LuaString>().toString();
     if (v.is<LuaInt>())
       return String(toString(v.get<LuaInt>()));
     if (v.is<LuaFloat>())
@@ -1579,35 +1619,39 @@ inline size_t LuaString::length() const {
 }
 
 inline String LuaString::toString() const {
-  return String(ptr());
+  return engine().string(handleIndex());
+}
+
+inline StringView LuaString::view() const {
+  return engine().stringView(handleIndex());
 }
 
 inline bool operator==(LuaString const& s1, LuaString const& s2) {
-  return std::strcmp(s1.ptr(), s2.ptr()) == 0;
+  return s1.view() == s2.view();
 }
 
 inline bool operator==(LuaString const& s1, char const* s2) {
-  return std::strcmp(s1.ptr(), s2) == 0;
+  return s1.view() == s2;
 }
 
 inline bool operator==(LuaString const& s1, std::string const& s2) {
-  return s1.ptr() == s2;
+  return s1.view() == s2;
 }
 
 inline bool operator==(LuaString const& s1, String const& s2) {
-  return s1.ptr() == s2;
+  return s1.view() == s2;
 }
 
 inline bool operator==(char const* s1, LuaString const& s2) {
-  return std::strcmp(s1, s2.ptr()) == 0;
+  return s2.view() == s1;
 }
 
 inline bool operator==(std::string const& s1, LuaString const& s2) {
-  return s1 == s2.ptr();
+  return s2.view() == s1;
 }
 
 inline bool operator==(String const& s1, LuaString const& s2) {
-  return s1 == s2.ptr();
+  return s2.view() == s1;
 }
 
 inline bool operator!=(LuaString const& s1, LuaString const& s2) {

source/core/StarLuaConverters.hpp

@@ -11,6 +11,23 @@
 
 namespace Star {
 
+template <typename T>
+struct LuaConverter<LuaNullTermWrapper<T>> : LuaConverter<T> {
+  static LuaValue from(LuaEngine& engine, LuaNullTermWrapper<T>&& v) {
+    auto enforcer = engine.nullTerminate();
+    return LuaConverter<T>::from(std::forward<T>(v));
+  }
+
+  static LuaValue from(LuaEngine& engine, LuaNullTermWrapper<T> const& v) {
+    auto enforcer = engine.nullTerminate();
+    return LuaConverter<T>::from(v);
+  }
+
+  static LuaNullTermWrapper<T> to(LuaEngine& engine, LuaValue const& v) {
+    return LuaConverter<T>::to(v);
+  }
+};
+
 template <typename T1, typename T2>
 struct LuaConverter<pair<T1, T2>> {
   static LuaValue from(LuaEngine& engine, pair<T1, T2>&& v) {

source/core/StarStringView.cpp

@@ -418,6 +418,14 @@ bool operator==(StringView s1, const char* s2) {
   return s1.m_view.compare(s2) == 0;
 }
 
+bool operator==(StringView s1, std::string const& s2) {
+  return s1.m_view.compare(s2) == 0;
+}
+
+bool operator==(StringView s1, String const& s2) {
+  return s1.m_view.compare(s2.utf8()) == 0;
+}
+
 bool operator==(StringView s1, StringView s2) {
   return s1.m_view == s2.m_view;
 }

source/core/StarStringView.hpp

@@ -96,6 +96,8 @@ public:
   StringView& operator=(StringView s);
 
   friend bool operator==(StringView s1, const char* s2);
+  friend bool operator==(StringView s1, std::string const& s2);
+  friend bool operator==(StringView s1, String const& s2);
   friend bool operator==(StringView s1, StringView s2);
   friend bool operator!=(StringView s1, StringView s2);
   friend bool operator<(StringView s1, StringView s2);

source/game/scripting/StarWorldLuaBindings.cpp

@@ -1421,7 +1421,7 @@ namespace LuaBindings {
     return {};
   }
 
-  Maybe<JsonArray> WorldEntityCallbacks::entityPortrait(World* world, EntityId entityId, String const& portraitMode) {
+  LuaNullTermWrapper<Maybe<JsonArray>> WorldEntityCallbacks::entityPortrait(World* world, EntityId entityId, String const& portraitMode) {
     auto entity = world->entity(entityId);
 
     if (auto portraitEntity = as<PortraitEntity>(entity)) {
@@ -1471,7 +1471,7 @@ namespace LuaBindings {
     return Json();
   }
 
-  Maybe<String> WorldEntityCallbacks::entityUniqueId(World* world, EntityId entityId) {
+  LuaNullTermWrapper<Maybe<String>> WorldEntityCallbacks::entityUniqueId(World* world, EntityId entityId) {
     if (auto entity = world->entity(entityId))
       return entity->uniqueId();
     return {};

source/game/scripting/StarWorldLuaBindings.hpp

@@ -122,10 +122,10 @@ namespace LuaBindings {
     Maybe<String> entityGender(World* world, EntityId entityId);
     Maybe<String> entityName(World* world, EntityId entityId);
     Maybe<String> entityDescription(World* world, EntityId entityId, Maybe<String> const& species);
-    Maybe<JsonArray> entityPortrait(World* world, EntityId entityId, String const& portraitMode);
+    LuaNullTermWrapper<Maybe<JsonArray>> entityPortrait(World* world, EntityId entityId, String const& portraitMode);
     Maybe<String> entityHandItem(World* world, EntityId entityId, String const& handName);
     Json entityHandItemDescriptor(World* world, EntityId entityId, String const& handName);
-    Maybe<String> entityUniqueId(World* world, EntityId entityId);
+    LuaNullTermWrapper<Maybe<String>> entityUniqueId(World* world, EntityId entityId);
     Json getObjectParameter(World* world, EntityId entityId, String const& parameterName, Maybe<Json> const& defaultValue);
     Json getNpcScriptParameter(World* world, EntityId entityId, String const& parameterName, Maybe<Json> const& defaultValue);
     List<Vec2I> objectSpaces(World* world, EntityId entityId);