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LuaState: Fixed stack balance when calling functions (#3428)

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This commit is contained in:
Mattes D 2016-11-10 16:46:31 +01:00 committed by GitHub
parent 0870649994
commit 9af17f7c39
2 changed files with 83 additions and 8 deletions
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34
src/Bindings/LuaState.cpp
View File

@ -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;
}

57
src/Bindings/LuaState.h
View File

@ -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);