ESOUI - PreHooking protected functions

ESOUI (https://www.esoui.com/forums/index.php)

- Tutorials & Other Helpful Info (https://www.esoui.com/forums/forumdisplay.php?f=172)

- - PreHooking protected functions (https://www.esoui.com/forums/showthread.php?t=6266)

PreHooking protected functions

Even if it's really simple, it's not in the esoui files, so ..

Lua Code:

--[[
ZO_PreHookProtected is a rewrite of ZO_PreHook. It accepts Protected functions.
IsProtectedFunction(existingFunctionName) will still return true even if existingFunctionName is not called
Calling existingFunctionName() will work, it will call your function and depending on your code will run the prehooked function
Calling CallSecureProtected("existingFunctionName", arg1) will work, it will call the original function only. You won't be able to "fake" other addons if they're correctly written, but mainly ESOUI code.
Don't hook a non-protected function with this PreHook or game won't load
]]--
function ZO_PreHookProtected(objectTable, existingFunctionName, hookFunction)
    if(type(objectTable) == "string") then
        hookFunction = existingFunctionName
        existingFunctionName = objectTable
        objectTable = _G
    end
 
    local newFn = function(...)
        if(not hookFunction(...)) then
        
            if IsProtectedFunction(existingFunctionName) then
                return CallSecureProtected(existingFunctionName, ...)
            end
            
        end
    end
 
    objectTable[existingFunctionName] = newFn
 
end

Doing this will mainly prehook ESOUI code and your own addon, so consider that the esoui code may not run because of another addon doing something else instead.

Could you provide an example using this hook? Thanks!!

I think you can use it as ZO_PreHook variant but ONLY for functions like UseItem() now.

Quote:

Don't hook a non-protected function with this PreHook or game won't load

If you return true inside your PreHook UseItem won't be executed if I understand it correctly?

Lua Code:

ZO_PreHookProtected('UseItem', MyUseItemFunction)
 
local function MyUseItemFunction(..)
   if doNotUseItem then
      return true
   end
end

That's it, just like PreHook.

Main goal is to add a backup of the prehooked func inside your hooking function to change its parameters. My first need was to redirect moves for crafting bag.