// Returns information about a specific function or function invocation.
//
// To get information about a function invocation, the parameter ar must be
// a valid activation record that was filled by a previous call to Getstack
// or given as argument to a hook.
//
// To get information about a function you push it onto the stack and start
// the what string with the character '>'. (In that case, Getinfo pops the
// function in the top of the stack.) For instance, to know in which line
// a function f was defined, you can write the following code:
//
// d := luajit.Newdebug(s)
// s.Getfield(luajit.Globalsindex, "f") // get global 'f'
// d.Getinfo(">S")
// fmt.Printf("%d\n", d.Linedefined);
//
// Each character in the string what selects some fields of the structure
// ar to be filled or a value to be pushed on the stack:
//
// 'n' fills in the field Name and Namewhat
// 'S' fills in the fields Source, Shortsrc, Linedefined,
// Lastlinedefined, and What
// 'l' fills in the field Currentline
// 'u' fills in the field Nups
// 'f' pushes onto the stack the function that is running at the
// given level
// 'L' pushes onto the stack a table whose indices are the numbers of
// the lines that are valid on the function. (A valid line is a line
// with some associated code, that is, a line where you can put a break
// point. Invalid lines include empty lines and comments.)
//
func (d *Debug) Getinfo(what string) error {
cs := C.CString(what)
defer C.free(unsafe.Pointer(cs))
if int(C.lua_getinfo(d.l, cs, d.d)) == 0 {
return errors.New("The significant owl hoots in the night.")
}
d.update()
return nil
}
// Returns the current stack trace
func (L *State) StackTrace() []LuaStackEntry {
r := []LuaStackEntry{}
var d C.lua_Debug
Sln := C.CString("Sln")
defer C.free(unsafe.Pointer(Sln))
for depth := 0; C.lua_getstack(L.s, C.int(depth), &d) > 0; depth++ {
C.lua_getinfo(L.s, Sln, &d)
ssb := make([]byte, C.LUA_IDSIZE)
for i := 0; i < C.LUA_IDSIZE; i++ {
ssb[i] = byte(d.short_src[i])
if ssb[i] == 0 {
ssb = ssb[:i]
break
}
}
ss := string(ssb)
r = append(r, LuaStackEntry{C.GoString(d.name), C.GoString(d.source), ss, int(d.currentline)})
}
return r
}
