Mouse input parser with luvit

example.lua

local Mouse = require('./mouse').Mouse
local table = require('table')

local mouse = Mouse:new('/dev/input/mouse1')

mouse:on('connected', function (dt)
  debug('mouse connected')
  local actions = {'moved', 'button'}
  -- register actions
  table.foreach(actions, function (i, v)
    mouse:on(v, debug)
  end)
end)

process:on('error', function (err)
  p('Error', err)
end)

mouse.lua

--[[
  @ Mouse bindings with luvit
  @ As seen on http://www.computer-engineering.org/ps2mouse/ and 
  @ https://github.com/luvit/luvit/blob/master/examples/linux-joystick.lua 
  @ Alejandro Morales <vamg008@gmail.com>
  @ license WTFPL
]]

local fs      = require('fs')
local Emitter = require('core').Emitter
local Buffer  = require('buffer').Buffer
local find    = require('string').find
local Bit     = require('bit')


local Mouse = Emitter:extend() -- Emitter instance

function Mouse:initialize(id, target, ...)  
  -- Emitter:wrap ->
  -- Utility that binds the named method `self[name]` for use as a callback.  The
  -- first argument (`err`) is re-routed to the "error" event instead.
  self:wrap('on_open')
  self:wrap('on_read')

  -- default configuration
  self.id = id or 1  -- default to mouse1
  self.target = target or '/dev/input/mouse'
  self.fullId = self.target .. self.id
  if target == nil and find(id, '/') then -- check for full path on first arg
    p('oh full path:', id)
    self.fullId = id
  end
  fs.open(self.fullId, 'r', '0644', self.on_open) -- "open" the device
end

function Mouse:on_open(fd)
  self.fd = fd
  self:emit('connected', { id = self.fullId, fd = self.fd, constructor = self })
  self:start_read()
end

function Mouse:start_read()
  fs.read(self.fd, nil, 8, self.on_read)
end

function Mouse:parse(buffer)
  local event = {
    -- Bit.band -> bitwise AND
    leftBtn   = Bit.band(buffer[1], 1  ) > 0, 
    rightBtn  = Bit.band(buffer[1], 2  ) > 0, 
    middleBtn = Bit.band(buffer[1], 4  ) > 0, 
    xSign     = Bit.band(buffer[1], 16 ) > 0, 
    ySign     = Bit.band(buffer[1], 32 ) > 0, 
    xOverflow = Bit.band(buffer[1], 64 ) > 0, 
    yOverflow = Bit.band(buffer[1], 128) > 0, 
    xDelta    = buffer:readInt8(1),   
    yDelta    = buffer:readInt8(2)    
  }
  if event.leftBtn or event.rightBtn or event.middleBtn then
    event.type = 'button'
  else
    event.type = 'moved'
  end
  return event
end

function Mouse:on_read(chunk)
  local event = Mouse:parse(Buffer:new(chunk))
  self:emit(event.type, event)
  if self.fd then self:start_read() end
end

function Mouse:close(callback)
  local fd = self.fd
  self.fd = nil
  fs.close(fd, callback)
end

-- Expose the Api
return { Mouse = Mouse}

package.lua

return {
    author = 'Alejandro Morales <vamg008@gmail.com>',
    name = 'Mouse handler',
    version = '0.0.1',
    description = 'Mouse input parser for luvit',
    main = 'mouse.lua'
}