From 754483ceb68c6d2a86f2e9a7d704bb1489b09ebd Mon Sep 17 00:00:00 2001 From: Matthew Wild Date: Tue, 13 Aug 2013 21:26:53 +0100 Subject: util.async: Add guarder method, to create guards to ensure only a single runner can pass through a section of code at a time --- util/async.lua | 38 +++++++++++++++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-) (limited to 'util/async.lua') diff --git a/util/async.lua b/util/async.lua index 8af8730f..32ed0542 100644 --- a/util/async.lua +++ b/util/async.lua @@ -43,6 +43,42 @@ local function waiter(num) end; end +function guarder() + local guards = {}; + return function (id, func) + local thread = coroutine.running(); + if not thread then + error("Not running in an async context, see http://prosody.im/doc/developers/async"); + end + local guard = guards[id]; + if not guard then + guard = {}; + guards[id] = guard; + log("debug", "New guard!"); + else + table.insert(guard, thread); + log("debug", "Guarded. %d threads waiting.", #guard) + coroutine.yield("wait"); + end + local function exit() + local next_waiting = table.remove(guard, 1); + if next_waiting then + log("debug", "guard: Executing next waiting thread (%d left)", #guard) + runner_continue(next_waiting); + else + log("debug", "Guard off duty.") + guards[id] = nil; + end + end + if func then + func(); + exit(); + return; + end + return exit; + end; +end + local runner_mt = {}; runner_mt.__index = runner_mt; @@ -119,4 +155,4 @@ function runner_mt:enqueue(input) table.insert(self.queue, input); end -return { waiter = waiter, runner = runner }; +return { waiter = waiter, guarder = guarder, runner = runner }; -- cgit v1.2.3