awesome/lib/gears/object.lua.in

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---------------------------------------------------------------------------
-- @author Uli Schlachter
-- @copyright 2010 Uli Schlachter
-- @release @AWESOME_VERSION@
---------------------------------------------------------------------------
local setmetatable = setmetatable
local pairs = pairs
local type = type
local error = error
module("gears.object")
-- Verify that obj is indeed a valid object as returned by new()
local function check(obj)
if type(obj) ~= "table" or type(obj._signals) ~= "table" then
error("add_signal() called on non-object")
end
end
-- Find a given signal
-- @param obj The object to search in
-- @param name The signal to find
-- @param error_msg Error message for if the signal is not found
-- @returns The signal table
local function find_signal(obj, name, error_msg)
check(obj)
if not obj._signals[name] then
error("Trying to " .. error_msg .. " non-existent signal")
end
return obj._signals[name]
end
-- Add a signal to an object. All signals must be added before they can be used.
-- @param obj The object
-- @param name The name of the new signal.
function add_signal(obj, name)
check(obj)
if not obj._signals[name] then
obj._signals[name] = {}
end
end
-- Connect to a signal
-- @param obj The object
-- @param name The name of the signal
-- @param func The callback to call when the signal is emitted
function connect_signal(obj, name, func)
local sig = find_signal(obj, name, "connect to")
sig[func] = func
end
-- Disonnect to a signal
-- @param obj The object
-- @param name The name of the signal
-- @param func The callback that should be disconnected
function disconnect_signal(obj, name, func)
local sig = find_signal(obj, name, "disconnect from")
sig[func] = nil
end
-- Emit a signal
-- @param obj The object
-- @param name The name of the signal
-- @param ... Extra arguments for the callback functions. Each connected
-- function receives the object as first argument and then any extra
-- arguments that are given to emit_signal()
function emit_signal(obj, name, ...)
local sig = find_signal(obj, name, "emit")
for func in pairs(sig) do
func(obj, ...)
end
end
-- Returns a new object. You can call :emit_signal(), :disconnect_signal,
-- :connect_signal() and :add_signal() on the resulting object.
local function new()
local ret = {}
-- Copy all our global functions to our new object
for k, v in pairs(_M) do
if type(v) == "function" then
ret[k] = v
end
end
ret._signals = {}
return ret
end
setmetatable(_M, { __call = function (_, ...) return new(...) end })
-- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=80