1 files changed, 85 insertions, 0 deletions
diff --git a/src/syslua/lx/mainloop.lua b/src/syslua/lx/mainloop.lua
new file mode 100644
index 0000000..c2ae88d
--- /dev/null
+++ b/src/syslua/lx/mainloop.lua
@@ -0,0 +1,85 @@
+local sys = require 'lx.sys'
+local sysdef = require 'lx.sysdef'
+
+local mainloop = {}
+
+local fds = {}
+local mainloop_must_exit = false
+local mainloop_fds_change = false
+
+function new_fd(fd, error_cb)
+	local fd = {
+		fd = fd,
+		error_cb = error_cb,
+		rd_expect = {},
+		wr_buf = "",
+	}
+	function fd:write(str)
+		-- TODO: try write immediately when possible
+		self.wr_buf = self.wr_buf .. str
+	end
+	function fd:expect(len, cb)
+		table.insert(self.rd_expect, {len, "", cb})
+	end
+end
+
+function mainloop.add_fd(fd, error_cb)
+	local fd = new_fd(fd, error_cb)
+	table.insert(fds, fd)
+	mainloop_fds_change = true
+	return fd
+end
+
+function mainloop.run()
+	mainloop_must_exit = false
+	sel_fds = {}
+	while not mainloop_must_exit do
+		local deadlock = true
+		for i, fd in pairs(fds) do
+			if mainloop_fds_change then
+				sel_fds[i] = {fd.fd}
+			end
+			local flags = sysdef.SEL_ERROR
+			if fd.rd_expect[1] then
+				flags = flags | sysdef.SEL_READ
+				deadlock = false
+			end
+			if #fd.wr_buf > 0 then
+				flags = flags | sysdef.SEL_WRITE
+				deadlock = false
+			end
+			sel_fds[i][2] = flags
+		end
+		mainloop_fds_change = false
+		assert(not deadlock, "Mainloop does nothing!")
+
+		local res = sys.select(sel_fds, -1)
+		assert(res, "select() call failed")
+		for i, fd = pairs(fds) do
+			local flags = sel_fds[i][3]
+			if flags & sysdef.SEL_ERROR ~= 0 then
+				fd.error_cb(fd)
+			else
+				if flags & sysdef.SEL_READ ~= 0 then
+					local reader = fd.rd_expect[1]
+					local tmp = sys.read(fd.fd, 0, reader[1] - #reader[2])
+					reader[2] = reader[2] .. tmp
+					if #reader[2] == reader[1] then
+						reader[3](reader[2])
+						table.remove(fd.rd_expect, 1)
+					end
+				end
+				if flags & sysdef.SEL_WRITE ~= 0 then
+					local r = sys.write(fd.fd, 0, fd.wr_buf)
+					fd.wr_buf = fd.wr_buf:sub(r+1)
+				end
+			end
+		end
+	end
+end
+
+function mainloop.exit()
+	mainloop_must_exit = true
+end
+
+return mainloop