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-rw-r--r--src/Bindings/LuaState.h57
1 files changed, 55 insertions, 2 deletions
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);