1 files changed, 96 insertions, 0 deletions
diff --git a/lib/awful/keygrabber.lua b/lib/awful/keygrabber.lua
new file mode 100644
index 0000000..4351f5b
--- /dev/null
+++ b/lib/awful/keygrabber.lua
@@ -0,0 +1,96 @@
+---------------------------------------------------------------------------
+--- Keygrabber Stack
+--
+-- @author dodo
+-- @copyright 2012 dodo
+-- @module awful.keygrabber
+---------------------------------------------------------------------------
+
+local ipairs = ipairs
+local table = table
+local capi = {
+    keygrabber = keygrabber }
+
+local keygrabber = {}
+
+-- Private data
+local grabbers = {}
+local keygrabbing = false
+
+
+local function grabber(mod, key, event)
+    for _, keygrabber_function in ipairs(grabbers) do
+        -- continue if the grabber explicitly returns false
+        if keygrabber_function(mod, key, event) ~= false then
+            break
+        end
+    end
+end
+
+--- Stop grabbing the keyboard for the provided callback.
+-- When no callback is given, the last grabber gets removed (last one added to
+-- the stack).
+-- @param g The key grabber that must be removed.
+function keygrabber.stop(g)
+    for i, v in ipairs(grabbers) do
+        if v == g then
+            table.remove(grabbers, i)
+            break
+        end
+    end
+    -- Stop the global key grabber if the last grabber disappears from stack.
+    if #grabbers == 0 then
+        keygrabbing = false
+        capi.keygrabber.stop()
+    end
+end
+
+---
+-- Grab keyboard input and read pressed keys, calling the least callback
+-- function from the stack at each keypress, until the stack is empty.
+--
+-- Calling run with the same callback again will bring the callback
+-- to the top of the stack.
+--
+-- The callback function receives three arguments:
+--
+-- * a table containing modifiers keys
+-- * a string with the pressed key
+-- * a string with either "press" or "release" to indicate the event type
+--
+-- A callback can return `false` to pass the events to the next
+-- keygrabber in the stack.
+-- @param g The key grabber callback that will get the key events until it will be deleted or a new grabber is added.
+-- @return the given callback `g`.
+-- @usage
+-- -- The following function can be bound to a key, and be used to resize a
+-- -- client using the keyboard.
+--
+-- function resize(c)
+--   local grabber = awful.keygrabber.run(function(mod, key, event)
+--     if event == "release" then return end
+--
+--     if     key == 'Up'    then awful.client.moveresize(0, 0, 0, 5, c)
+--     elseif key == 'Down'  then awful.client.moveresize(0, 0, 0, -5, c)
+--     elseif key == 'Right' then awful.client.moveresize(0, 0, 5, 0, c)
+--     elseif key == 'Left'  then awful.client.moveresize(0, 0, -5, 0, c)
+--     else   awful.keygrabber.stop(grabber)
+--     end
+--   end)
+-- end
+function keygrabber.run(g)
+    -- Remove the grabber if it is in the stack.
+    keygrabber.stop(g)
+    -- Record the grabber that has been added most recently.
+    table.insert(grabbers, 1, g)
+    -- Start the keygrabber if it is not running already.
+    if not keygrabbing then
+        keygrabbing = true
+        capi.keygrabber.run(grabber)
+    end
+    return g
+end
+
+return keygrabber
+
+-- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80