--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/etc/dispatch.lua	Tue Aug 26 18:40:01 2008 -0700
@@ -0,0 +1,302 @@
+-----------------------------------------------------------------------------
+-- A hacked dispatcher module
+-- LuaSocket sample files
+-- Author: Diego Nehab
+-- RCS ID: $$
+-----------------------------------------------------------------------------
+local base = _G
+local table = require("table")
+local socket = require("socket")
+local coroutine = require("coroutine")
+module("dispatch")
+
+-- if too much time goes by without any activity in one of our sockets, we
+-- just kill it
+TIMEOUT = 60
+
+-----------------------------------------------------------------------------
+-- We implement 3 types of dispatchers:
+--     sequential
+--     coroutine
+--     threaded
+-- The user can choose whatever one is needed
+-----------------------------------------------------------------------------
+local handlert = {}
+
+-- default handler is coroutine
+function newhandler(mode)
+    mode = mode or "coroutine"
+    return handlert[mode]()
+end
+
+local function seqstart(self, func)
+    return func()
+end
+
+-- sequential handler simply calls the functions and doesn't wrap I/O
+function handlert.sequential()
+    return {
+        tcp = socket.tcp,
+        start = seqstart
+    }
+end
+
+-----------------------------------------------------------------------------
+-- Mega hack. Don't try to do this at home.
+-----------------------------------------------------------------------------
+-- we can't yield across calls to protect, so we rewrite it with coxpcall
+-- make sure you don't require any module that uses socket.protect before
+-- loading our hack
+function socket.protect(f)
+  return function(...)
+    local co = coroutine.create(f)
+    while true do
+      local results = {coroutine.resume(co, base.unpack(arg))}
+      local status = table.remove(results, 1)
+      if not status then
+        if type(results[1]) == 'table' then
+          return nil, results[1][1]
+        else base.error(results[1]) end
+      end
+      if coroutine.status(co) == "suspended" then
+        arg = {coroutine.yield(base.unpack(results))}
+      else
+        return base.unpack(results)
+      end
+    end
+  end
+end
+
+-----------------------------------------------------------------------------
+-- Simple set data structure. O(1) everything.
+-----------------------------------------------------------------------------
+local function newset()
+    local reverse = {}
+    local set = {}
+    return base.setmetatable(set, {__index = {
+        insert = function(set, value)
+            if not reverse[value] then
+                table.insert(set, value)
+                reverse[value] = table.getn(set)
+            end
+        end,
+        remove = function(set, value)
+            local index = reverse[value]
+            if index then
+                reverse[value] = nil
+                local top = table.remove(set)
+                if top ~= value then
+                    reverse[top] = index
+                    set[index] = top
+                end
+            end
+        end
+    }})
+end
+
+-----------------------------------------------------------------------------
+-- socket.tcp() wrapper for the coroutine dispatcher
+-----------------------------------------------------------------------------
+local function cowrap(dispatcher, tcp, error)
+    if not tcp then return nil, error end
+    -- put it in non-blocking mode right away
+    tcp:settimeout(0)
+    -- metatable for wrap produces new methods on demand for those that we
+    -- don't override explicitly.
+    local metat = { __index = function(table, key)
+        table[key] = function(...)
+            arg[1] = tcp
+            return tcp[key](base.unpack(arg))
+        end
+        return table[key]
+    end}
+    -- does our user want to do his own non-blocking I/O?
+    local zero = false
+    -- create a wrap object that will behave just like a real socket object
+    local wrap = {  }
+    -- we ignore settimeout to preserve our 0 timeout, but record whether
+    -- the user wants to do his own non-blocking I/O
+    function wrap:settimeout(value, mode)
+        if value == 0 then zero = true
+        else zero = false end
+        return 1
+    end
+    -- send in non-blocking mode and yield on timeout
+    function wrap:send(data, first, last)
+        first = (first or 1) - 1
+        local result, error
+        while true do
+            -- return control to dispatcher and tell it we want to send
+            -- if upon return the dispatcher tells us we timed out,
+            -- return an error to whoever called us
+            if coroutine.yield(dispatcher.sending, tcp) == "timeout" then
+                return nil, "timeout"
+            end
+            -- try sending
+            result, error, first = tcp:send(data, first+1, last)
+            -- if we are done, or there was an unexpected error,
+            -- break away from loop
+            if error ~= "timeout" then return result, error, first end
+        end
+    end
+    -- receive in non-blocking mode and yield on timeout
+    -- or simply return partial read, if user requested timeout = 0
+    function wrap:receive(pattern, partial)
+        local error = "timeout"
+        local value
+        while true do
+            -- return control to dispatcher and tell it we want to receive
+            -- if upon return the dispatcher tells us we timed out,
+            -- return an error to whoever called us
+            if coroutine.yield(dispatcher.receiving, tcp) == "timeout" then
+                return nil, "timeout"
+            end
+            -- try receiving
+            value, error, partial = tcp:receive(pattern, partial)
+            -- if we are done, or there was an unexpected error,
+            -- break away from loop. also, if the user requested
+            -- zero timeout, return all we got
+            if (error ~= "timeout") or zero then
+                return value, error, partial
+            end
+        end
+    end
+    -- connect in non-blocking mode and yield on timeout
+    function wrap:connect(host, port)
+        local result, error = tcp:connect(host, port)
+        if error == "timeout" then
+            -- return control to dispatcher. we will be writable when
+            -- connection succeeds.
+            -- if upon return the dispatcher tells us we have a
+            -- timeout, just abort
+            if coroutine.yield(dispatcher.sending, tcp) == "timeout" then
+                return nil, "timeout"
+            end
+            -- when we come back, check if connection was successful
+            result, error = tcp:connect(host, port)
+            if result or error == "already connected" then return 1
+            else return nil, "non-blocking connect failed" end
+        else return result, error end
+    end
+    -- accept in non-blocking mode and yield on timeout
+    function wrap:accept()
+        while 1 do
+            -- return control to dispatcher. we will be readable when a
+            -- connection arrives.
+            -- if upon return the dispatcher tells us we have a
+            -- timeout, just abort
+            if coroutine.yield(dispatcher.receiving, tcp) == "timeout" then
+                return nil, "timeout"
+            end
+            local client, error = tcp:accept()
+            if error ~= "timeout" then
+                return cowrap(dispatcher, client, error)
+            end
+        end
+    end
+    -- remove cortn from context
+    function wrap:close()
+        dispatcher.stamp[tcp] = nil
+        dispatcher.sending.set:remove(tcp)
+        dispatcher.sending.cortn[tcp] = nil
+        dispatcher.receiving.set:remove(tcp)
+        dispatcher.receiving.cortn[tcp] = nil
+        return tcp:close()
+    end
+    return base.setmetatable(wrap, metat)
+end
+
+
+-----------------------------------------------------------------------------
+-- Our coroutine dispatcher
+-----------------------------------------------------------------------------
+local cometat = { __index = {} }
+
+function schedule(cortn, status, operation, tcp)
+    if status then
+        if cortn and operation then
+            operation.set:insert(tcp)
+            operation.cortn[tcp] = cortn
+            operation.stamp[tcp] = socket.gettime()
+        end
+    else base.error(operation) end
+end
+
+function kick(operation, tcp)
+    operation.cortn[tcp] = nil
+    operation.set:remove(tcp)
+end
+
+function wakeup(operation, tcp)
+    local cortn = operation.cortn[tcp]
+    -- if cortn is still valid, wake it up
+    if cortn then
+        kick(operation, tcp)
+        return cortn, coroutine.resume(cortn)
+    -- othrewise, just get scheduler not to do anything
+    else
+        return nil, true
+    end
+end
+
+function abort(operation, tcp)
+    local cortn = operation.cortn[tcp]
+    if cortn then
+        kick(operation, tcp)
+        coroutine.resume(cortn, "timeout")
+    end
+end
+
+-- step through all active cortns
+function cometat.__index:step()
+    -- check which sockets are interesting and act on them
+    local readable, writable = socket.select(self.receiving.set,
+        self.sending.set, 1)
+    -- for all readable connections, resume their cortns and reschedule
+    -- when they yield back to us
+    for _, tcp in base.ipairs(readable) do
+        schedule(wakeup(self.receiving, tcp))
+    end
+    -- for all writable connections, do the same
+    for _, tcp in base.ipairs(writable) do
+        schedule(wakeup(self.sending, tcp))
+    end
+    -- politely ask replacement I/O functions in idle cortns to
+    -- return reporting a timeout
+    local now = socket.gettime()
+    for tcp, stamp in base.pairs(self.stamp) do
+        if tcp.class == "tcp{client}" and now - stamp > TIMEOUT then
+            abort(self.sending, tcp)
+            abort(self.receiving, tcp)
+        end
+    end
+end
+
+function cometat.__index:start(func)
+    local cortn = coroutine.create(func)
+    schedule(cortn, coroutine.resume(cortn))
+end
+
+function handlert.coroutine()
+    local stamp = {}
+    local dispatcher = {
+        stamp = stamp,
+        sending  = {
+            name = "sending",
+            set = newset(),
+            cortn = {},
+            stamp = stamp
+        },
+        receiving = {
+            name = "receiving",
+            set = newset(),
+            cortn = {},
+            stamp = stamp
+        },
+    }
+    function dispatcher.tcp()
+        return cowrap(dispatcher, socket.tcp())
+    end
+    return base.setmetatable(dispatcher, cometat)
+end
+