net.cqueues: Add module that allows use of cqueues while still using net.server as...

diff --git a/net/cqueues.lua b/net/cqueues.lua
new file mode 100644 (file)
index 0000000..e82fe4a
--- /dev/null
+++ b/net/cqueues.lua
@@ -0,0 +1,65 @@
+-- Prosody IM
+-- Copyright (C) 2014 Daurnimator
+--
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+-- This module allows you to use cqueues with a net.server mainloop
+--
+
+local server = require "net.server";
+local cqueues = require "cqueues";
+
+-- Create a single top level cqueue
+local cq;
+
+if server.cq then -- server provides cqueues object
+       cq = server.cq;
+elseif server.get_backend() == "select" and server._addtimer then -- server_select
+       cq = cqueues.new();
+       local function step()
+               assert(cq:loop(0));
+       end
+
+       -- Use wrapclient (as wrapconnection isn't exported) to get server_select to watch cq fd
+       local handler = server.wrapclient({
+               getfd = function() return cq:pollfd(); end;
+               settimeout = function() end; -- Method just needs to exist
+               close = function() end; -- Need close method for 'closeall'
+       }, nil, nil, {});
+
+       -- Only need to listen for readable; cqueues handles everything under the hood
+       -- readbuffer is called when `select` notes an fd as readable
+       handler.readbuffer = step;
+
+       -- Use server_select low lever timer facility,
+       -- this callback gets called *every* time there is a timeout in the main loop
+       server._addtimer(function(current_time)
+               -- This may end up in extra step()'s, but cqueues handles it for us.
+               step();
+               return cq:timeout();
+       end);
+elseif server.event and server.base then -- server_event
+       cq = cqueues.new();
+       -- Only need to listen for readable; cqueues handles everything under the hood
+       local EV_READ = server.event.EV_READ;
+       server.base:addevent(cq:pollfd(), EV_READ, function(e)
+                       assert(cq:loop(0));
+                       -- Convert a cq timeout to an acceptable timeout for luaevent
+                       local t = cq:timeout();
+                       if t == 0 then -- if you give luaevent 0, it won't call this callback again
+                               t = 0.000001; -- 1 microsecond is the smallest that works (goes into a `struct timeval`)
+                       elseif t == nil then -- you always need to give a timeout, pick something big if we don't have one
+                               t = 0x7FFFFFFF; -- largest 32bit int
+                       end
+                       return EV_READ, t;
+               end,
+               -- Schedule the callback to fire on first tick to ensure any cq:wrap calls that happen during start-up are serviced.
+               0.000001);
+else
+       error "NYI"
+end
+
+return {
+       cq = cq;
+}