refactor: extract ctype constructors

Author: MunifTanjim

evdev/device.lua

@@ -1,5 +1,6 @@
 local ffi = require("ffi")
 
+local input = require("evdev.linux.input")
 local Event = require("evdev.event")
 local evdev = require("evdev.libevdev")
 local util = require("evdev.util")
@@ -8,6 +9,8 @@ local libevdev_grab_mode = evdev.enum.libevdev_grab_mode
 local libevdev_read_flag = evdev.enum.libevdev_read_flag
 local open_flag = util.enum.open_flag
 
+local new_libevdev_ptr = ffi.typeof("struct libevdev *[1]")
+
 ---@class Device
 ---@field fd number
 ---@field pathname string
@@ -30,7 +33,7 @@ local function init(class, pathname, flags)
 
   self.fd = fd
 
-  local dev_ptr = ffi.new("struct libevdev *[1]")
+  local dev_ptr = new_libevdev_ptr()
 
   local rc = evdev.libevdev_new_from_fd(fd, dev_ptr)
   if rc < 0 then
@@ -194,10 +197,10 @@ end
 
 ---@param ev_type number
 ---@param code number
----@param value_ptr? ffi.cdata*
+---@param value_ptr? ffi.cdata*|{ [0]: number }
 ---@return number|nil
 function Device:fetch_event_value(ev_type, code, value_ptr)
-  value_ptr = value_ptr or ffi.new("int[1]")
+  value_ptr = value_ptr or input.new_int_ptr()
   local rc = evdev.libevdev_fetch_event_value(self.dev, ev_type, code, value_ptr)
   if rc ~= 0 then
     return value_ptr[0]
@@ -213,10 +216,10 @@ end
 
 ---@param slot number
 ---@param code number
----@param value_ptr? ffi.cdata*
+---@param value_ptr? ffi.cdata*|{ [0]: number }
 ---@return number|nil
 function Device:fetch_slot_value(slot, code, value_ptr)
-  value_ptr = value_ptr or ffi.new("int[1]")
+  value_ptr = value_ptr or input.new_int_ptr()
   local rc = evdev.libevdev_fetch_slot_value(self.dev, slot, code, value_ptr)
   if rc ~= 0 then
     return value_ptr[0]
@@ -252,9 +255,9 @@ end
 function Device:enable_event_code(ev_type, code, data)
   local data_type = type(data)
   if data_type == "number" then
-    data = ffi.new("int", data)
+    data = input.new_int(data)
   elseif data_type == "table" then
-    data = ffi.new("struct input_absinfo", data)
+    data = input.new_input_absinfo(data)
   end
 
   return evdev.libevdev_enable_event_code(self.dev, ev_type, code, data)

evdev/event.lua

@@ -1,5 +1,3 @@
-local ffi = require("ffi")
-
 local input = require("evdev.linux.input")
 
 ---@class Event
@@ -12,7 +10,7 @@ local function init(class, ev)
   ---@type Event
   local self = setmetatable({}, { __index = class })
 
-  self.ev = ev or ffi.new("struct input_event")
+  self.ev = ev or input.new_input_event()
 
   return self
 end

evdev/linux/input.lua

@@ -124,7 +124,9 @@ struct ff_effect {
 ---@alias evdev_input_absinfo { value: number, minimum: number, maximum: number, fuzz: number, flat: number, resolution: number }
 
 local int = ffi.typeof("int")
+local int_ptr = ffi.typeof("int[1]")
 local uint2 = ffi.typeof("unsigned int[2]")
+local input_event = ffi.typeof("struct input_event")
 local input_id = ffi.typeof("struct input_id")
 local input_absinfo = ffi.typeof("struct input_absinfo")
 local input_keymap_entry = ffi.typeof("struct input_keymap_entry")
@@ -205,6 +207,18 @@ local mod = {
   EVIOCSCLOCKID = _IOW("E", 0xa0, int),
 }
 
+---@type fun(init: number|nil): ffi.ctype*
+mod.new_int = int
+
+---@type fun(): ffi.ctype*|{ [0]: number }
+mod.new_int_ptr = int_ptr
+
+---@type fun(): ffi.ctype*|evdev_input_event
+mod.new_input_event = input_event
+
+---@type fun(init: evdev_input_absinfo|nil): ffi.ctype*|evdev_input_absinfo
+mod.new_input_absinfo = input_absinfo
+
 local const = require("evdev.linux.input-constant")
 
 mod.grouped_constant = const