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Bubberstation/code/modules/admin/verbs/lua/lua_state.dm
Y0SH1M4S73R 6bb24ac773 Fixes hard-dels related to lua signal handlers (#69555)
When I changed the syntax of SS13.lua to account for the ability to properly index tables with datums, it turns out that the callbacks created for signal handlers and timeouts had circular references, resulting in hard-deletes.

My first solution was to make it so signal handler and timeout callbacks use weakrefs, which get resolved in lua_state/call_function, but it turns out that, when calling the signal cleanup function, a qdeleted-but-not-yet-garbage-collected datum's weakref resolves to null because datum.gc_collected is set to GC_CURRENTLY_BEING_QDELETED before COMSIG_PARENT_QDELETING gets sent.

To resolve this issue, Potato and Oranges both recommended that I make a snowflake variant of resolve which ignores whether the datum a weakref points to is qdeleted - only that it is null or it's weakref isn't the very weakref resolve was called on. This proc was given a lengthy autodoc comment describing when it should or shouldn't be used, to ensure it is only used in cases similar to the one I needed to create it for (needing to resolve a weakref to a datum in a COMSIG_PARENT_QDELETING handler registered on that very datum).
2022-09-01 10:30:59 +01:00

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#define MAX_LOG_REPEAT_LOOKBACK 5
GLOBAL_VAR_INIT(IsLuaCall, FALSE)
GLOBAL_PROTECT(IsLuaCall)
GLOBAL_DATUM(lua_usr, /mob)
GLOBAL_PROTECT(lua_usr)
/datum/lua_state
var/name
/// The internal ID of the lua state stored in auxlua's global map
var/internal_id
/// A log of every return, yield, and error for each chunk execution and function call
var/list/log = list()
/// A list of all the variables in the state's environment
var/list/globals = list()
/// A list in which to store datums and lists instantiated in lua, ensuring that they don't get garbage collected
var/list/references = list()
/datum/lua_state/vv_edit_var(var_name, var_value)
. = ..()
if(var_name == NAMEOF(src, internal_id))
return FALSE
/datum/lua_state/New(_name)
if(SSlua.initialized != TRUE)
qdel(src)
return
name = _name
internal_id = __lua_new_state()
/datum/lua_state/proc/check_if_slept(result)
if(result["status"] == "sleeping")
SSlua.sleeps += src
/datum/lua_state/proc/log_result(result, verbose = TRUE)
if(!islist(result))
return
if(!verbose && result["status"] != "errored" && result["status"] != "bad return" \
&& !(result["name"] == "input" && (result["status"] == "finished" || length(result["param"]))))
return
var/append_to_log = TRUE
var/index_of_log
if(log.len)
for(var/index in log.len to max(log.len - MAX_LOG_REPEAT_LOOKBACK, 1) step -1)
var/list/entry = log[index]
if(entry["status"] == result["status"] \
&& entry["chunk"] == result["chunk"] \
&& entry["name"] == result["name"] \
&& ((entry["param"] == result["param"]) || deep_compare_list(entry["param"], result["param"])))
if(!entry["repeats"])
entry["repeats"] = 0
index_of_log = index
entry["repeats"]++
append_to_log = FALSE
break
if(append_to_log)
if(islist(result["param"]))
result["param"] = weakrefify_list(encode_text_and_nulls(result["param"]))
log += list(result)
index_of_log = log.len
INVOKE_ASYNC(src, /datum/lua_state.proc/update_editors)
return index_of_log
/datum/lua_state/proc/load_script(script)
GLOB.IsLuaCall = TRUE
var/tmp_usr = GLOB.lua_usr
GLOB.lua_usr = usr
var/result = __lua_load(internal_id, script)
GLOB.IsLuaCall = FALSE
GLOB.lua_usr = tmp_usr
// Internal errors unrelated to the code being executed are returned as text rather than lists
if(isnull(result))
result = list("status" = "errored", "param" = "__lua_load returned null (it may have runtimed - check the runtime logs)", "name" = "input")
if(istext(result))
result = list("status" = "errored", "param" = result, "name" = "input")
result["chunk"] = script
check_if_slept(result)
log_lua("[key_name(usr)] executed the following lua code:\n<code>[script]</code>")
return result
/datum/lua_state/proc/call_function(function, ...)
var/call_args = length(args) > 1 ? args.Copy(2) : list()
if(islist(function))
var/list/new_function_path = list()
for(var/path_element in function)
if(isweakref(path_element))
var/datum/weakref/weak_ref = path_element
var/resolved = weak_ref.hard_resolve()
if(!resolved)
return list("status" = "errored", "param" = "Weakref in function path ([weak_ref] \ref[weak_ref]) resolved to null.", "name" = jointext(function, "."))
new_function_path += resolved
else
new_function_path += path_element
function = new_function_path
var/msg = "[key_name(usr)] called the lua function \"[function]\" with arguments: [english_list(call_args)]"
log_lua(msg)
var/tmp_usr = GLOB.lua_usr
GLOB.lua_usr = usr
GLOB.IsLuaCall = TRUE
var/result = __lua_call(internal_id, function, call_args)
GLOB.IsLuaCall = FALSE
GLOB.lua_usr = tmp_usr
if(isnull(result))
result = list("status" = "errored", "param" = "__lua_call returned null (it may have runtimed - check the runtime logs)", "name" = islist(function) ? jointext(function, ".") : function)
if(istext(result))
result = list("status" = "errored", "param" = result, "name" = islist(function) ? jointext(function, ".") : function)
check_if_slept(result)
return result
/datum/lua_state/proc/call_function_return_first(function, ...)
var/list/result = call_function(arglist(args))
log_result(result, verbose = FALSE)
if(length(result))
if(islist(result["param"]) && length(result["param"]))
return result["param"][1]
/datum/lua_state/proc/awaken()
GLOB.IsLuaCall = TRUE
var/result = __lua_awaken(internal_id)
GLOB.IsLuaCall = FALSE
if(isnull(result))
result = list("status" = "errored", "param" = "__lua_awaken returned null (it may have runtimed - check the runtime logs)", "name" = "An attempted awaken")
if(istext(result))
result = list("status" = "errored", "param" = result, "name" = "An attempted awaken")
check_if_slept(result)
return result
/// Prefer calling SSlua.queue_resume over directly calling this
/datum/lua_state/proc/resume(index, ...)
var/call_args = length(args) > 1 ? args.Copy(2) : list()
var/msg = "[key_name(usr)] resumed a lua coroutine with arguments: [english_list(call_args)]"
log_lua(msg)
GLOB.IsLuaCall = TRUE
var/result = __lua_resume(internal_id, index, call_args)
GLOB.IsLuaCall = FALSE
if(isnull(result))
result = list("status" = "errored", "param" = "__lua_resume returned null (it may have runtimed - check the runtime logs)", "name" = "An attempted resume")
if(istext(result))
result = list("status" = "errored", "param" = result, "name" = "An attempted resume")
check_if_slept(result)
return result
/datum/lua_state/proc/get_globals()
globals = weakrefify_list(encode_text_and_nulls(__lua_get_globals(internal_id)))
/datum/lua_state/proc/get_tasks()
return __lua_get_tasks(internal_id)
/datum/lua_state/proc/kill_task(task_info)
__lua_kill_task(internal_id, task_info)
/datum/lua_state/proc/update_editors()
var/list/editor_list = LAZYACCESS(SSlua.editors, "\ref[src]")
if(editor_list)
for(var/datum/lua_editor/editor as anything in editor_list)
SStgui.update_uis(editor)
#undef MAX_LOG_REPEAT_LOOKBACK