Merge pull request #3341 from cuberite/LuaStateImprovements

cLuaState improvements

src/Bindings/BindingsProcessor.lua

@@ -234,7 +234,6 @@ local function OutputLuaStateHelpers(a_Package)
 			if not(g_HasCustomPushImplementation[item.name]) then
 				f:write("void cLuaState::Push(" .. item.name .. " * a_Value)\n{\n\tASSERT(IsValid());\n")
 				f:write("\ttolua_pushusertype(m_LuaState, a_Value, \"" .. item.name .. "\");\n");
-				f:write("\tm_NumCurrentFunctionArgs += 1;\n")
 				f:write("}\n\n\n\n\n\n")
 			end
 		end

src/Bindings/LuaJson.cpp

@@ -82,7 +82,7 @@ void PushJsonValue(const Json::Value & a_Value, cLuaState & a_LuaState)
 	{
 		case Json::nullValue:
 		{
-			a_LuaState.PushNil();
+			a_LuaState.Push(cLuaState::Nil);
 			break;
 		}
 
@@ -228,8 +228,7 @@ static int tolua_cJson_Parse(lua_State * a_LuaState)
 	Json::Reader reader;
 	if (!reader.parse(input, root, false))
 	{
-		L.PushNil();
-		L.Push(Printf("Parsing Json failed: %s", reader.getFormattedErrorMessages().c_str()));
+		L.Push(cLuaState::Nil, Printf("Parsing Json failed: %s", reader.getFormattedErrorMessages().c_str()));
 		return 2;
 	}
 

src/Bindings/LuaState.cpp

@@ -42,6 +42,7 @@ extern "C"
 
 
 const cLuaState::cRet cLuaState::Return = {};
+const cLuaState::cNil cLuaState::Nil = {};
 
 /** Each Lua state stores a pointer to its creating cLuaState in Lua globals, under this name.
 This way any cLuaState can reference the main cLuaState's TrackedCallbacks, mutex etc. */
@@ -341,6 +342,33 @@ void cLuaState::cStackTable::ForEachArrayElement(std::function<bool(cLuaState &
 
 
 
+void cLuaState::cStackTable::ForEachElement(std::function<bool(cLuaState & a_LuaState)> a_ElementCallback) const
+{
+	#ifdef _DEBUG
+		auto stackTop = lua_gettop(m_LuaState);
+	#endif
+	lua_pushvalue(m_LuaState, m_StackPos);  // Stk: <table>
+	lua_pushnil(m_LuaState);                // Stk: <table> nil
+	while (lua_next(m_LuaState, -2))        // Stk: <table> <key> <val>
+	{
+		auto shouldAbort = a_ElementCallback(m_LuaState);
+		ASSERT(lua_gettop(m_LuaState) == stackTop + 3);  // The element callback must not change the Lua stack below the value
+		lua_pop(m_LuaState, 1);  // Stk: <table> <key>
+		if (shouldAbort)
+		{
+			// The callback wants to abort
+			lua_pop(m_LuaState, 2);  // Stk: empty
+			return;
+		}
+	}
+	// Stk: <table>
+	lua_pop(m_LuaState, 1);  // Stk: empty
+}
+
+
+
+
+
 ////////////////////////////////////////////////////////////////////////////////
 // cLuaState:
 
@@ -724,24 +752,29 @@ bool cLuaState::PushFunction(const cRef & a_TableRef, const char * a_FnName)
 
 
 
-void cLuaState::PushNil(void)
+void cLuaState::Push(const AString & a_String)
 {
 	ASSERT(IsValid());
 
-	lua_pushnil(m_LuaState);
-	m_NumCurrentFunctionArgs += 1;
+	lua_pushlstring(m_LuaState, a_String.data(), a_String.size());
 }
 
 
 
 
 
-void cLuaState::Push(const AString & a_String)
+void cLuaState::Push(const AStringMap & a_Dictionary)
 {
 	ASSERT(IsValid());
 
-	lua_pushlstring(m_LuaState, a_String.data(), a_String.size());
-	m_NumCurrentFunctionArgs += 1;
+	lua_createtable(m_LuaState, 0, static_cast<int>(a_Dictionary.size()));
+	int newTable = lua_gettop(m_LuaState);
+	for (const auto & item: a_Dictionary)
+	{
+		Push(item.first);   // key
+		Push(item.second);  // value
+		lua_rawset(m_LuaState, newTable);
+	}
 }
 
 
@@ -760,7 +793,6 @@ void cLuaState::Push(const AStringVector & a_Vector)
 		tolua_pushstring(m_LuaState, itr->c_str());
 		lua_rawseti(m_LuaState, newTable, index);
 	}
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -772,7 +804,6 @@ void cLuaState::Push(const cCraftingGrid * a_Grid)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, reinterpret_cast<void *>(const_cast<cCraftingGrid *>(a_Grid)), "cCraftingGrid");
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -784,7 +815,6 @@ void cLuaState::Push(const cCraftingRecipe * a_Recipe)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, reinterpret_cast<void *>(const_cast<cCraftingRecipe *>(a_Recipe)), "cCraftingRecipe");
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -796,7 +826,6 @@ void cLuaState::Push(const char * a_Value)
 	ASSERT(IsValid());
 
 	tolua_pushstring(m_LuaState, a_Value);
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -808,7 +837,17 @@ void cLuaState::Push(const cItems & a_Items)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, reinterpret_cast<void *>(const_cast<cItems *>(&a_Items)), "cItems");
-	m_NumCurrentFunctionArgs += 1;
+}
+
+
+
+
+
+void cLuaState::Push(const cNil & a_Nil)
+{
+	ASSERT(IsValid());
+
+	lua_pushnil(m_LuaState);
 }
 
 
@@ -820,7 +859,6 @@ void cLuaState::Push(const cPlayer * a_Player)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, reinterpret_cast<void *>(const_cast<cPlayer *>(a_Player)), "cPlayer");
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -832,7 +870,6 @@ void cLuaState::Push(const cLuaState::cRef & a_Ref)
 	ASSERT(IsValid());
 
 	lua_rawgeti(m_LuaState, LUA_REGISTRYINDEX, static_cast<int>(a_Ref));
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -844,7 +881,6 @@ void cLuaState::Push(const HTTPRequest * a_Request)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, reinterpret_cast<void *>(const_cast<HTTPRequest *>(a_Request)), "HTTPRequest");
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -856,7 +892,6 @@ void cLuaState::Push(const HTTPTemplateRequest * a_Request)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, reinterpret_cast<void *>(const_cast<HTTPTemplateRequest *>(a_Request)), "HTTPTemplateRequest");
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -868,7 +903,6 @@ void cLuaState::Push(const Vector3d & a_Vector)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, reinterpret_cast<void *>(const_cast<Vector3d *>(&a_Vector)), "Vector3<double>");
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -880,7 +914,6 @@ void cLuaState::Push(const Vector3d * a_Vector)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, reinterpret_cast<void *>(const_cast<Vector3d *>(a_Vector)), "Vector3<double>");
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -892,7 +925,6 @@ void cLuaState::Push(const Vector3i & a_Vector)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, reinterpret_cast<void *>(const_cast<Vector3i *>(&a_Vector)), "Vector3<int>");
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -904,7 +936,6 @@ void cLuaState::Push(const Vector3i * a_Vector)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, reinterpret_cast<void *>(const_cast<Vector3i *>(a_Vector)), "Vector3<int>");
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -916,7 +947,6 @@ void cLuaState::Push(bool a_Value)
 	ASSERT(IsValid());
 
 	tolua_pushboolean(m_LuaState, a_Value ? 1 : 0);
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -981,8 +1011,6 @@ void cLuaState::Push(cEntity * a_Entity)
 			}
 		}  // switch (EntityType)
 	}
-
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -994,7 +1022,6 @@ void cLuaState::Push(cLuaServerHandle * a_ServerHandle)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, a_ServerHandle, "cServerHandle");
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -1006,7 +1033,6 @@ void cLuaState::Push(cLuaTCPLink * a_TCPLink)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, a_TCPLink, "cTCPLink");
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -1018,7 +1044,6 @@ void cLuaState::Push(cLuaUDPEndpoint * a_UDPEndpoint)
 	ASSERT(IsValid());
 
 	tolua_pushusertype(m_LuaState, a_UDPEndpoint, "cUDPEndpoint");
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -1030,7 +1055,6 @@ void cLuaState::Push(double a_Value)
 	ASSERT(IsValid());
 
 	tolua_pushnumber(m_LuaState, a_Value);
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -1042,7 +1066,6 @@ void cLuaState::Push(int a_Value)
 	ASSERT(IsValid());
 
 	tolua_pushnumber(m_LuaState, a_Value);
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -1054,7 +1077,6 @@ void cLuaState::Push(long a_Value)
 	ASSERT(IsValid());
 
 	tolua_pushnumber(m_LuaState, static_cast<lua_Number>(a_Value));
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -1066,7 +1088,6 @@ void cLuaState::Push(UInt32 a_Value)
 	ASSERT(IsValid());
 
 	tolua_pushnumber(m_LuaState, a_Value);
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -1078,7 +1099,6 @@ void cLuaState::Push(std::chrono::milliseconds a_Value)
 	ASSERT(IsValid());
 
 	tolua_pushnumber(m_LuaState, static_cast<lua_Number>(a_Value.count()));
-	m_NumCurrentFunctionArgs += 1;
 }
 
 
@@ -1090,7 +1110,6 @@ void cLuaState::Pop(int a_NumValuesToPop)
 	ASSERT(IsValid());
 
 	lua_pop(m_LuaState, a_NumValuesToPop);
-	m_NumCurrentFunctionArgs -= a_NumValuesToPop;
 }
 
 
@@ -1113,6 +1132,37 @@ bool cLuaState::GetStackValue(int a_StackPos, AString & a_Value)
 
 
 
+bool cLuaState::GetStackValue(int a_StackPos, AStringMap & a_Value)
+{
+	// Retrieve all values in a string => string dictionary table:
+	if (!lua_istable(m_LuaState, a_StackPos))
+	{
+		return false;
+	}
+	cStackTable tbl(*this, a_StackPos);
+	bool isValid = true;
+	tbl.ForEachElement([&isValid, &a_Value](cLuaState & a_LuaState)
+		{
+			AString key, val;
+			if (a_LuaState.GetStackValues(-2, key, val))
+			{
+				a_Value[key] = val;
+			}
+			else
+			{
+				isValid = false;
+				return true;
+			}
+			return false;
+		}
+	);
+	return isValid;
+}
+
+
+
+
+
 bool cLuaState::GetStackValue(int a_StackPos, bool & a_ReturnedVal)
 {
 	a_ReturnedVal = (tolua_toboolean(m_LuaState, a_StackPos, a_ReturnedVal ? 1 : 0) > 0);

src/Bindings/LuaState.h

@@ -309,14 +309,39 @@ public:
 	typedef UniquePtr<cTableRef> cTableRefPtr;
 
 
+	/** Represents a parameter that is optional - calling a GetStackValue() with this object will not fail if the value on the Lua stack is nil.
+	Note that the GetStackValue() will still fail if the param is present but of a different type.
+	The class itself is just a marker so that the template magic will select the correct GetStackValue() overload. */
+	template <typename T>
+	class cOptionalParam
+	{
+	public:
+		explicit cOptionalParam(T & a_Dest):
+			m_Dest(a_Dest)
+		{
+		}
+
+		T & GetDest(void) { return m_Dest; }
+
+	protected:
+		T & m_Dest;
+	};
+
+
 	/** A dummy class that's used only to delimit function args from return values for cLuaState::Call() */
 	class cRet
 	{
 	} ;
-
 	static const cRet Return;  // Use this constant to delimit function args from return values for cLuaState::Call()
 
 
+	/** A dummy class that's used only to push a constant nil as a function parameter in Call(). */
+	class cNil
+	{
+	};
+	static const cNil Nil;  // Use this constant to give a function a nil parameter in Call()
+
+
 	/** A RAII class for values pushed onto the Lua stack.
 	Will pop the value off the stack in the destructor. */
 	class cStackValue
@@ -471,15 +496,15 @@ public:
 		Push(std::forward<Arg2>(a_Arg2), std::forward<Args>(a_Args)...);
 	}
 
-	void PushNil(void);
-
 	// Push a const value onto the stack (keep alpha-sorted):
 	void Push(const AString & a_String);
+	void Push(const AStringMap & a_Dictionary);
 	void Push(const AStringVector & a_Vector);
 	void Push(const cCraftingGrid * a_Grid);
 	void Push(const cCraftingRecipe * a_Recipe);
 	void Push(const char * a_Value);
 	void Push(const cItems & a_Items);
+	void Push(const cNil & a_Nil);
 	void Push(const cPlayer * a_Player);
 	void Push(const cRef & a_Ref);
 	void Push(const HTTPRequest * a_Request);
@@ -508,6 +533,7 @@ public:
 	// Returns whether value was changed
 	// Enum values are checked for their allowed values and fail if the value is not assigned.
 	bool GetStackValue(int a_StackPos, AString & a_Value);
+	bool GetStackValue(int a_StackPos, AStringMap & a_Value);
 	bool GetStackValue(int a_StackPos, bool & a_Value);
 	bool GetStackValue(int a_StackPos, cCallback & a_Callback);
 	bool GetStackValue(int a_StackPos, cCallbackPtr & a_Callback);
@@ -549,6 +575,17 @@ public:
 		return true;
 	}
 
+	/** Retrieves an optional value on the stack - doesn't fail if the stack contains nil instead of the value. */
+	template <typename T>
+	bool GetStackValue(int a_StackPos, cOptionalParam<T> && a_ReturnedVal)
+	{
+		if (lua_isnoneornil(m_LuaState, a_StackPos))
+		{
+			return true;
+		}
+		return GetStackValue(a_StackPos, a_ReturnedVal.GetDest());
+	}
+
 	/** Pushes the named value in the table at the top of the stack.
 	a_Name may be a path containing multiple table levels, such as "cChatColor.Blue".
 	If the value is found, it is pushed on top of the stack and the returned cStackValue is valid.
@@ -597,6 +634,7 @@ public:
 	template <typename FnT, typename... Args>
 	bool Call(const FnT & a_Function, Args &&... args)
 	{
+		m_NumCurrentFunctionArgs = -1;
 		if (!PushFunction(std::forward<const FnT &>(a_Function)))
 		{
 			// Pushing the function failed
@@ -606,14 +644,14 @@ public:
 	}
 
 	/** Retrieves a list of values from the Lua stack, starting at the specified index. */
-	template <typename T, typename... Args>
-	inline bool GetStackValues(int a_StartStackPos, T & a_Ret, Args &&... args)
+	template <typename Arg1, typename... Args>
+	inline bool GetStackValues(int a_StartStackPos, Arg1 && a_Arg1, Args &&... args)
 	{
-		if (!GetStackValue(a_StartStackPos, a_Ret))
+		if (!GetStackValue(a_StartStackPos, std::forward<Arg1>(a_Arg1)))
 		{
 			return false;
 		}
-		return GetStackValues(a_StartStackPos + 1, args...);
+		return GetStackValues(a_StartStackPos + 1, std::forward<Args>(args)...);
 	}
 
 	/** Returns true if the specified parameters on the stack are of the specified usertable type; also logs warning if not. Used for static functions */
@@ -758,6 +796,7 @@ protected:
 	inline bool PushCallPop(T && a_Param, Args &&... args)
 	{
 		Push(std::forward<T>(a_Param));
+		m_NumCurrentFunctionArgs += 1;
 		return PushCallPop(std::forward<Args>(args)...);
 	}
 

src/Bindings/ManualBindings.cpp

@@ -2058,8 +2058,7 @@ static int tolua_cUrlParser_Parse(lua_State * a_LuaState)
 	if (!res.first)
 	{
 		// Error, return nil and error msg:
-		L.PushNil();
-		L.Push(res.second);
+		L.Push(cLuaState::Nil, res.second);
 		return 2;
 	}
 	L.Push(scheme, username, password, host, port, path, query, fragment);
@@ -2099,8 +2098,7 @@ static int tolua_cUrlParser_ParseAuthorityPart(lua_State * a_LuaState)
 	if (!res.first)
 	{
 		// Error, return nil and error msg:
-		L.PushNil();
-		L.Push(res.second);
+		L.Push(cLuaState::Nil, res.second);
 		return 2;
 	}
 	L.Push(username, password, host, port);

src/Bindings/ManualBindings_Network.cpp

@@ -649,8 +649,7 @@ static int tolua_cTCPLink_StartTLSClient(lua_State * L)
 	AString res = Link->StartTLSClient(OwnCert, OwnPrivKey, OwnPrivKeyPassword);
 	if (!res.empty())
 	{
-		S.PushNil();
-		S.Push(Printf("Cannot start TLS on link to %s:%d: %s", Link->GetRemoteIP().c_str(), Link->GetRemotePort(), res.c_str()));
+		S.Push(cLuaState::Nil, Printf("Cannot start TLS on link to %s:%d: %s", Link->GetRemoteIP().c_str(), Link->GetRemotePort(), res.c_str()));
 		return 2;
 	}
 	return 1;
@@ -695,10 +694,10 @@ static int tolua_cTCPLink_StartTLSServer(lua_State * L)
 	AString res = Link->StartTLSServer(OwnCert, OwnPrivKey, OwnPrivKeyPassword, StartTLSData);
 	if (!res.empty())
 	{
-		S.PushNil();
-		S.Push(Printf("Cannot start TLS on link to %s:%d: %s", Link->GetRemoteIP().c_str(), Link->GetRemotePort(), res.c_str()));
+		S.Push(cLuaState::Nil, Printf("Cannot start TLS on link to %s:%d: %s", Link->GetRemoteIP().c_str(), Link->GetRemotePort(), res.c_str()));
 		return 2;
 	}
+	S.Push(true);
 	return 1;
 }