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-rw-r--r--src/Bindings/LuaState.cpp34
-rw-r--r--src/Bindings/LuaState.h57
2 files changed, 83 insertions, 8 deletions
diff --git a/src/Bindings/LuaState.cpp b/src/Bindings/LuaState.cpp
index 81893c946..50ce04f7c 100644
--- a/src/Bindings/LuaState.cpp
+++ b/src/Bindings/LuaState.cpp
@@ -549,6 +549,8 @@ void cLuaState::Detach(void)
void cLuaState::AddPackagePath(const AString & a_PathVariable, const AString & a_Path)
{
+ ASSERT_LUA_STACK_BALANCE(m_LuaState);
+
// Get the current path:
lua_getfield(m_LuaState, LUA_GLOBALSINDEX, "package"); // Stk: <package>
lua_getfield(m_LuaState, -1, a_PathVariable.c_str()); // Stk: <package> <package.path>
@@ -574,6 +576,7 @@ void cLuaState::AddPackagePath(const AString & a_PathVariable, const AString & a
bool cLuaState::LoadFile(const AString & a_FileName, bool a_LogWarnings)
{
ASSERT(IsValid());
+ ASSERT_LUA_STACK_BALANCE(m_LuaState);
// Load the file:
int s = luaL_loadfile(m_LuaState, a_FileName.c_str());
@@ -588,7 +591,7 @@ bool cLuaState::LoadFile(const AString & a_FileName, bool a_LogWarnings)
}
// Execute the globals:
- s = lua_pcall(m_LuaState, 0, LUA_MULTRET, 0);
+ s = lua_pcall(m_LuaState, 0, 0, 0);
if (s != 0)
{
if (a_LogWarnings)
@@ -609,6 +612,7 @@ bool cLuaState::LoadFile(const AString & a_FileName, bool a_LogWarnings)
bool cLuaState::LoadString(const AString & a_StringToLoad, const AString & a_FileName, bool a_LogWarnings)
{
ASSERT(IsValid());
+ ASSERT_LUA_STACK_BALANCE(m_LuaState);
// Load the file:
int s = luaL_loadstring(m_LuaState, a_StringToLoad.c_str());
@@ -649,6 +653,7 @@ bool cLuaState::HasFunction(const char * a_FunctionName)
return false;
}
+ ASSERT_LUA_STACK_BALANCE(m_LuaState);
lua_getglobal(m_LuaState, a_FunctionName);
bool res = (!lua_isnil(m_LuaState, -1) && lua_isfunction(m_LuaState, -1));
lua_pop(m_LuaState, 1);
@@ -1475,12 +1480,15 @@ bool cLuaState::CallFunction(int a_NumResults)
{
// The error has already been printed together with the stacktrace
LOGWARNING("Error in %s calling function %s()", m_SubsystemName.c_str(), CurrentFunctionName.c_str());
+
+ // Remove the error handler and error message from the stack:
+ ASSERT(lua_gettop(m_LuaState) == 2);
+ lua_pop(m_LuaState, 2);
return false;
}
// Remove the error handler from the stack:
lua_remove(m_LuaState, -a_NumResults - 1);
-
return true;
}
@@ -2101,6 +2109,7 @@ void cLuaState::LogStackValues(const char * a_Header)
void cLuaState::LogStackValues(lua_State * a_LuaState, const char * a_Header)
{
// Format string consisting only of %s is used to appease the compiler
+ ASSERT_LUA_STACK_BALANCE(a_LuaState, false);
LOG("%s", (a_Header != nullptr) ? a_Header : "Lua C API Stack contents:");
for (int i = lua_gettop(a_LuaState); i > 0; i--)
{
@@ -2111,9 +2120,22 @@ void cLuaState::LogStackValues(lua_State * a_LuaState, const char * a_Header)
case LUA_TBOOLEAN: Value.assign((lua_toboolean(a_LuaState, i) != 0) ? "true" : "false"); break;
case LUA_TLIGHTUSERDATA: Printf(Value, "%p", lua_touserdata(a_LuaState, i)); break;
case LUA_TNUMBER: Printf(Value, "%f", static_cast<double>(lua_tonumber(a_LuaState, i))); break;
- case LUA_TSTRING: Printf(Value, "%s", lua_tostring(a_LuaState, i)); break;
+ case LUA_TSTRING:
+ {
+ size_t len;
+ const char * txt = lua_tolstring(a_LuaState, i, &len);
+ Value.assign(txt, std::min<size_t>(len, 50)); // Only log up to 50 characters of the string
+ break;
+ }
case LUA_TTABLE: Printf(Value, "%p", lua_topointer(a_LuaState, i)); break;
- case LUA_TUSERDATA: Printf(Value, "%p (%s)", lua_touserdata(a_LuaState, i), tolua_typename(a_LuaState, i)); break;
+ case LUA_TFUNCTION: Printf(Value, "%p", lua_topointer(a_LuaState, i)); break;
+ case LUA_TUSERDATA:
+ {
+ Printf(Value, "%p (%s)", lua_touserdata(a_LuaState, i), tolua_typename(a_LuaState, i));
+ // tolua_typename pushes the string onto Lua stack, pop it off again:
+ lua_pop(a_LuaState, 1);
+ break;
+ }
default: break;
}
LOGD(" Idx %d: type %d (%s) %s", i, Type, lua_typename(a_LuaState, Type), Value.c_str());
@@ -2164,6 +2186,7 @@ int cLuaState::ReportFnCallErrors(lua_State * a_LuaState)
int cLuaState::BreakIntoDebugger(lua_State * a_LuaState)
{
+ ASSERT_LUA_STACK_BALANCE(a_LuaState);
// Call the BreakIntoDebugger function, if available:
lua_getglobal(a_LuaState, "BreakIntoDebugger");
if (!lua_isfunction(a_LuaState, -1))
@@ -2172,11 +2195,10 @@ int cLuaState::BreakIntoDebugger(lua_State * a_LuaState)
lua_pop(a_LuaState, 1);
return 1;
}
- lua_insert(a_LuaState, -2); // Copy the string that has been passed to us
+ lua_pushvalue(a_LuaState, -2); // Copy the string that has been passed to us
LOGD("Calling BreakIntoDebugger()...");
lua_call(a_LuaState, 1, 0);
LOGD("Returned from BreakIntoDebugger().");
-
return 0;
}
diff --git a/src/Bindings/LuaState.h b/src/Bindings/LuaState.h
index 32d346a19..9c97e96d4 100644
--- a/src/Bindings/LuaState.h
+++ b/src/Bindings/LuaState.h
@@ -55,6 +55,54 @@ class cLuaState
{
public:
+ #ifdef _DEBUG
+ /** Asserts that the Lua stack has the same amount of entries when this object is destructed, as when it was constructed.
+ Used for checking functions that should preserve Lua stack balance. */
+ class cStackBalanceCheck
+ {
+ public:
+ cStackBalanceCheck(const char * a_FileName, int a_LineNum, lua_State * a_LuaState, bool a_ShouldLogStack = true):
+ m_FileName(a_FileName),
+ m_LineNum(a_LineNum),
+ m_LuaState(a_LuaState),
+ m_StackPos(lua_gettop(a_LuaState))
+ {
+ if (a_ShouldLogStack)
+ {
+ // DEBUG: If an unbalanced stack is reported, uncommenting the next line can help debug the imbalance
+ // cLuaState::LogStackValues(a_LuaState, Printf("Started checking Lua stack balance, currently %d items:", m_StackPos).c_str());
+ // Since LogStackValues() itself uses the balance check, we must not call it recursively
+ }
+ }
+
+ ~cStackBalanceCheck()
+ {
+ auto currStackPos = lua_gettop(m_LuaState);
+ if (currStackPos != m_StackPos)
+ {
+ LOGD("Lua stack not balanced. Expected %d items, found %d items. Stack watching started in %s:%d",
+ m_StackPos, currStackPos,
+ m_FileName.c_str(), m_LineNum
+ );
+ cLuaState::LogStackValues(m_LuaState);
+ ASSERT(!"Lua stack unbalanced"); // If this assert fires, the Lua stack is inbalanced, check the callstack / m_FileName / m_LineNum
+ }
+ }
+
+ protected:
+ const AString m_FileName;
+ int m_LineNum;
+ lua_State * m_LuaState;
+ int m_StackPos;
+ };
+
+ #define STRINGIFY2(X, Y) X##Y
+ #define STRINGIFY(X, Y) STRINGIFY2(X, Y)
+ #define ASSERT_LUA_STACK_BALANCE(...) cStackBalanceCheck STRINGIFY(Check, __COUNTER__)(__FILE__, __LINE__, __VA_ARGS__)
+ #else
+ #define ASSERT_LUA_STACK_BALANCE(...)
+ #endif
+
/** Provides a RAII-style locking for the LuaState.
Used mainly by the cPluginLua internals to provide the actual locking for interface operations, such as callbacks. */
class cLock
@@ -654,13 +702,15 @@ public:
template <typename FnT, typename... Args>
bool Call(const FnT & a_Function, Args &&... args)
{
+ ASSERT_LUA_STACK_BALANCE(m_LuaState);
m_NumCurrentFunctionArgs = -1;
if (!PushFunction(std::forward<const FnT &>(a_Function)))
{
// Pushing the function failed
return false;
}
- return PushCallPop(std::forward<Args>(args)...);
+ auto res = PushCallPop(std::forward<Args>(args)...);
+ return res;
}
/** Retrieves a list of values from the Lua stack, starting at the specified index. */
@@ -873,7 +923,10 @@ protected:
/**
Calls the function that has been pushed onto the stack by PushFunction(),
with arguments pushed by PushXXX().
- Returns true if successful, logs a warning on failure.
+ Returns true if successful, returns false and logs a warning on failure.
+ Pops the function params, the function itself and the error handler off the stack.
+ If successful, leaves a_NumReturnValues new values on Lua stack, corresponding to the return values.
+ On failure, leaves no new values on the Lua stack.
*/
bool CallFunction(int a_NumReturnValues);