Cheat Engine

[predprey]

So I'm thinking of doing a server plugin that can allow users to connect to the host PC through a browser on any device (i.e. mobile phones) on the same LAN. So users may easily activate/deactivate memory records without alt-tabbing or getting up from the couch to reach their keyboard.

But I can't find a suitable exported function for getting the addresslist. Currently, I have two ideas in mind. Preferably, I will code in C/C++ using the Wt framework and get all necessary information through the Lua engine, caveat being that it requires a lot of reads from the Lua stack.

Alternatively, I can code using Lazarus and get all the tree nodes through the mainform pointer. But the web frameworks available for FreePascal seems lacking.

So, is there any other way I can get the addresslist to the plugin?

[Dark Byte]

easiest is just use lua and invoke some lua functions like activateMemrec(id) or deactivateMemrec(id)

to call just do:
lua_getglobal(l,"activateMemrec")
lua_pushinteger(id)
lua_pcall(l,1,0,0)

and use luaL_doString ("......") to load your functions

[predprey]

Thanks, looks like I'll take the C++ option.

[Dark Byte]

If you have questions about lua, just ask. it's usually easier than it appears

[predprey]

I'm getting Lua Panic errors by setting a timer to continuously refresh the client page.

---------------------------
Timer Exception
---------------------------
:TApplication->MainForm:TMainForm->pnlExtraMemRecInfo:TCEPanel->:TTimer:External exception E06D7363

Seems there is a conflict with CE's own update timer. Any ideas what might be causing it? My timer does access the addresslist through Lua every second, but I did check that the stack is managed and popped properly after each memory record retrieval. It doesn't crash or freeze immediately when these errors pop up and the addresslist state is synchronized between the browser and CE still. However, once such errors pops up, CE will lock up when closing. So it's not a problem I can ignore.

[Dark Byte]

do you use the lua state variable passed by the callback?

you're creating new timers constantly?
do you use threads ?

it could be your c++ code is running destructors on some objects using wrong typecasts or another exception (
https://blogs.msdn.microsoft.com/oldnewthing/20100730-00/?p=13273 )
and try without other extensions. perhaps they are conflicting (e.g pnlExtraMemRecInfo:TCEPanel is not a native CE object)

[predprey]

I set the lua state taken from the exported functions as a global variable. The server instance is started on a separate thread. Timers are only created per web session e.g. refreshing/new user browsing.

I have a feeling it's my extension causing it. Totally forgot I had that extension. Thanks.

[Dark Byte]

on function callbacks from lua always use the parameter it provides. Every thread has a unique lua state and functions can be called from other threads.

if you access lua from a new state, use the getLuaState function to get a new one

[predprey]

So I have been thinking how to implement server push and eliminate the refresh timer on the client side. To do so I would need some way to detect a change in the addresslist. But CE does not support some of the TTreeView events that can easily be used for this e.g. OnAddition.

Thus, I currently have 2 ideas for it:
1. Do a timer on server side instead and periodically check for addresslist changes, either by saving the table and diff-ing the hash or individually check each memrec.

2. Use other events instead such as OnClick, OnMouseExit that are implemented in CE. However, this leaves some gaps where some actions will not be detected and pushed to clients.

Are there any better options I can go for?

[Dark Byte]

right now there's not mich i can think of. OnChange won't work ? (all published properties are available to lua)

[predprey]

Yea, OnChange is a TTVChangedEvent, which is hidden in ceguicomponents.pas. I could make use of it, on top on OnAddition, OnDeletion and a few others.

It's fine though, I will just make use of what I have for now and update the plugin again as and when the events become available in future CE versions. Thanks for all the help till now.

[Dark Byte]

the addresslist isn't a ceguicomponent, it's a TTreeviewWithScroll which is a TtreeView which does have those properties published. (
https://github.com/cheat-engine/cheat-engine/blob/master/Cheat%20Engine/addresslist.pas )

if you're talking about something else like a component you created yourself then use the TTreeview component instead

see https://cheatengine.org/forum/viewtopic.php?p=5739406#5739406 for an example

[predprey]

[Dark Byte]

ah ok, i didn't check the type. i'll see about exposing more typedefs