File

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−-- Prosody IM
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−-- Copyright (C) 2014 Daurnimator
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−--
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−-- This project is MIT/X11 licensed. Please see the
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−-- COPYING file in the source package for more information.
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−--
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−-- This module allows you to use cqueues with a net.server mainloop
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−--
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−
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−local server = require "net.server";
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−local cqueues = require "cqueues";
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−assert(cqueues.VERSION >= 20150113, "cqueues newer than 20150113 required")
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−
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−-- Create a single top level cqueue
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−local cq;
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−
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−if server.cq then -- server provides cqueues object
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−	cq = server.cq;
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−elseif server.get_backend() == "select" and server._addtimer then -- server_select
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−	cq = cqueues.new();
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−	local function step()
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−		assert(cq:loop(0));
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−	end
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−
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−	-- Use wrapclient (as wrapconnection isn't exported) to get server_select to watch cq fd
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−	local handler = server.wrapclient({
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−		getfd = function() return cq:pollfd(); end;
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−		settimeout = function() end; -- Method just needs to exist
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−		close = function() end; -- Need close method for 'closeall'
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−	}, nil, nil, {});
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−
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−	-- Only need to listen for readable; cqueues handles everything under the hood
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−	-- readbuffer is called when `select` notes an fd as readable
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−	handler.readbuffer = step;
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−
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−	-- Use server_select low lever timer facility,
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−	-- this callback gets called *every* time there is a timeout in the main loop
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−	server._addtimer(function(current_time)
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−		-- This may end up in extra step()'s, but cqueues handles it for us.
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−		step();
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−		return cq:timeout();
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−	end);
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−elseif server.event and server.base then -- server_event
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−	cq = cqueues.new();
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−	-- Only need to listen for readable; cqueues handles everything under the hood
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−	local EV_READ = server.event.EV_READ;
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−	-- Convert a cqueues timeout to an acceptable timeout for luaevent
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−	local function luaevent_safe_timeout(cq)
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−		local t = cq:timeout();
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−		-- if you give luaevent 0 or nil, it re-uses the previous timeout.
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−		if t == 0 then
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−			t = 0.000001; -- 1 microsecond is the smallest that works (goes into a `struct timeval`)
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−		elseif t == nil then -- pick something big if we don't have one
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−			t = 0x7FFFFFFF; -- largest 32bit int
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−		end
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−		return t
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−	end
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−	local event_handle;
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−	event_handle = server.base:addevent(cq:pollfd(), EV_READ, function(e)
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−			-- Need to reference event_handle or this callback will get collected
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−			-- This creates a circular reference that can only be broken if event_handle is manually :close()'d
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−			local _ = event_handle;
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−			-- Run as many cqueues things as possible (with a timeout of 0)
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−			-- If an error is thrown, it will break the libevent loop; but prosody resumes after logging a top level error
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−			assert(cq:loop(0));
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−			return EV_READ, luaevent_safe_timeout(cq);
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−		end, luaevent_safe_timeout(cq));
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−else
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−	error "NYI"
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−end
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−
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−return {
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−	cq = cq;
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−}