1 files changed, 107 insertions, 0 deletions
diff --git a/lem/signal.lua b/lem/signal.lua
new file mode 100644
index 0000000..6dbf060
--- /dev/null
+++ b/lem/signal.lua
@@ -0,0 +1,107 @@
+--
+-- This file is part of LEM, a Lua Event Machine.
+-- Copyright 2013 Asbjørn Sloth Tønnesen
+--
+-- LEM is free software: you can redistribute it and/or modify it
+-- under the terms of the GNU Lesser General Public License as
+-- published by the Free Software Foundation, either version 3 of
+-- the License, or (at your option) any later version.
+--
+-- LEM is distributed in the hope that it will be useful, but
+-- WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU Lesser General Public License for more details.
+--
+-- You should have received a copy of the GNU Lesser General Public
+-- License along with LEM.  If not, see <http://www.gnu.org/licenses/>.
+--
+
+local core = require 'lem.signal.core'
+
+local queues = {}
+
+local function fire(signal, ...)
+	local queue = queues[signal]
+	for i = 1, #queue do
+		queue[i](signal, ...)
+	end
+end
+
+local install_signal_handler
+do
+	local installed = false
+	function install_signal_handler()
+		if not installed then
+			core.sethandler(function(signal, ...)
+				fire(signal, ...)
+			end)
+			installed = true
+		end
+	end
+end
+
+local signal_install, signal_uninstall
+do
+	local installed = {}
+
+	function signal_install(sig)
+		if installed[sig] then
+			return true
+		end
+
+		install_signal_handler()
+
+		local ret, err = core.watch(sig)
+		if not ret then return nil, err end
+
+		installed[sig] = true
+		return true
+	end
+
+	function signal_uninstall(sig)
+		if not installed[sig] then
+			return true
+		end
+
+		local ret, err = core.unwatch(sig)
+		if not ret then return nil, err end
+
+		installed[sig] = nil
+		return true
+	end
+end
+
+local M = {}
+
+function M.register(signum, func)
+	if not signum then return nil, 'unknown signal' end
+
+	local queue = queues[signum]
+	if queue == nil then
+		queue = {}
+		queues[signum] = queue
+	end
+	table.insert(queue, func)
+	return signal_install(signum)
+end
+
+function M.unregister(signum, func)
+	if not signum then return nil, 'unknown signal' end
+
+	local queue = queues[signum]
+	if queue then
+		for i = 1, #queue do
+			if queue[i] == func then
+				table.remove(queue, i)
+			end
+		end
+		if #queue == 0 then
+			return signal_uninstall(signum)
+		end
+	end
+	return true
+end
+
+return M
+
+-- vim: ts=2 sw=2 noet: