File

net/cqueues.lua @ 9090:56c52cb4d44e

util.dataforms: Exclude descriptive text fields from forms of type 'submit' The receiving end presumably already have the original form, so these potentially long text fields are of little value.
author Kim Alvefur <zash@zash.se>
date Fri, 03 Aug 2018 21:45:55 +0200
parent 6538:f1eb66288f60
child 10996:d742095046f9
line wrap: on
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-- 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";
assert(cqueues.VERSION >= 20150113, "cqueues newer than 20150113 required")

-- 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;
	-- Convert a cqueues timeout to an acceptable timeout for luaevent
	local function luaevent_safe_timeout(cq)
		local t = cq:timeout();
		-- if you give luaevent 0 or nil, it re-uses the previous timeout.
		if t == 0 then
			t = 0.000001; -- 1 microsecond is the smallest that works (goes into a `struct timeval`)
		elseif t == nil then -- pick something big if we don't have one
			t = 0x7FFFFFFF; -- largest 32bit int
		end
		return t
	end
	local event_handle;
	event_handle = server.base:addevent(cq:pollfd(), EV_READ, function(e)
			-- Need to reference event_handle or this callback will get collected
			-- This creates a circular reference that can only be broken if event_handle is manually :close()'d
			local _ = event_handle;
			-- Run as many cqueues things as possible (with a timeout of 0)
			-- If an error is thrown, it will break the libevent loop; but prosody resumes after logging a top level error
			assert(cq:loop(0));
			return EV_READ, luaevent_safe_timeout(cq);
		end, luaevent_safe_timeout(cq));
else
	error "NYI"
end

return {
	cq = cq;
}