summaryrefslogtreecommitdiff
path: root/Build/source/texk/web2c/luatexdir/luasocket/etc/dispatch.lua
blob: 248541554080c181d7ef2942fd1c4e47a5a4a9f2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
-----------------------------------------------------------------------------
-- A hacked dispatcher module
-- LuaSocket sample files
-- Author: Diego Nehab
-----------------------------------------------------------------------------
local base = _G
local table = require("table")
local string = require("string")
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 on Lua 5.1, so we rewrite it with
-- coroutines
-- make sure you don't require any module that uses socket.protect before
-- loading our hack
if string.sub(base._VERSION, -3) == "5.1" then
  local function _protect(co, status, ...)
    if not status then
      local msg = ...
      if base.type(msg) == 'table' then
        return nil, msg[1]
      else
        base.error(msg, 0)
      end
    end
    if coroutine.status(co) == "suspended" then
      return _protect(co, coroutine.resume(co, coroutine.yield(...)))
    else
      return ...
    end
  end

  function socket.protect(f)
    return function(...)
      local co = coroutine.create(f)
      return _protect(co, coroutine.resume(co, ...))
    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] = #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(...)
            return tcp[key](tcp,select(2,...))
        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