--
-- LANES.LUA
--
-- Multithreading and -core support for Lua
--
-- Authors: Asko Kauppi <akauppi@gmail.com>
-- Benoit Germain <bnt.germain@gmail.com>
--
-- History: see CHANGES
--
--[[
===============================================================================
Copyright (C) 2007-10 Asko Kauppi <akauppi@gmail.com>
Copyright (C) 2010-13 Benoit Germain <bnt.germain@gmail.com>
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
===============================================================================
]]--
-- Lua 5.1: module() creates a global variable
-- Lua 5.2: module() is gone
-- almost everything module() does is done by require() anyway
-- -> simply create a table, populate it, return it, and be done
local lanes = {}
lanes.configure = function( _params)
-- This check is for sublanes requiring Lanes
--
-- TBD: We could also have the C level expose 'string.gmatch' for us. But this is simpler.
--
if not string then
error( "To use 'lanes', you will also need to have 'string' available.", 2)
end
--
-- Cache globals for code that might run under sandboxing
--
local assert = assert
local string_gmatch = assert( string.gmatch)
local select = assert( select)
local type = assert( type)
local pairs = assert( pairs)
local tostring = assert( tostring)
local error = assert( error)
local default_params =
{
nb_keepers = 1,
on_state_create = nil,
shutdown_timeout = 0.25,
with_timers = true,
track_lanes = nil,
verbose_errors = false,
-- LuaJIT provides a thread-unsafe allocator by default, so we need to protect it when used in parallel lanes
protect_allocator = (jit and jit.version) and true or false
}
local param_checkers =
{
nb_keepers = function( _val)
-- nb_keepers should be a number > 0
return type( _val) == "number" and _val > 0
end,
with_timers = function( _val)
-- with_timers may be nil or boolean
if _val then
return type( _val) == "boolean"
else
return true -- _val is either false or nil
end
end,
protect_allocator = function( _val)
-- protect_allocator may be nil or boolean
if _val then
return type( _val) == "boolean"
else
return true -- _val is either false or nil
end
end,
on_state_create = function( _val)
-- on_state_create may be nil or a function
return _val and type( _val) == "function" or true
end,
shutdown_timeout = function( _val)
-- shutdown_timeout should be a number >= 0
return type( _val) == "number" and _val >= 0
end,
track_lanes = function( _val)
-- track_lanes may be nil or boolean
return _val and type( _val) == "boolean" or true
end,
verbose_errors = function( _val)
-- verbose_errors may be nil or boolean
if _val then
return type( _val) == "boolean"
else
return true -- _val is either false or nil
end
end
}
local params_checker = function( _params)
if not _params then
return default_params
end
if type( _params) ~= "table" then
error( "Bad parameter #1 to lanes.configure(), should be a table")
end
-- any setting not present in the provided parameters takes the default value
for key, value in pairs( default_params) do
local my_param = _params[key]
local param
if my_param ~= nil then
param = my_param
else
param = default_params[key]
end
if not param_checkers[key]( param) then
error( "Bad " .. key .. ": " .. tostring( param), 2)
end
_params[key] = param
end
return _params
end
_params = params_checker( _params)
local core = require "lanes.core"
assert( type( core)=="table")
-- configure() is available only the first time lanes.core is required process-wide, and we *must* call it to have the other functions in the interface
if core.configure then core.configure( _params.nb_keepers, _params.on_state_create, _params.shutdown_timeout, _params.track_lanes, _params.protect_allocator, _params.verbose_errors) end
local thread_new = assert( core.thread_new)
local set_singlethreaded = assert( core.set_singlethreaded)
local max_prio = assert( core.max_prio)
lanes.ABOUT=
{
author= "Asko Kauppi <akauppi@gmail.com>, Benoit Germain <bnt.germain@gmail.com>",
description= "Running multiple Lua states in parallel",
license= "MIT/X11",
copyright= "Copyright (c) 2007-10, Asko Kauppi; (c) 2011-12, Benoit Germain",
version = assert( core.version)
}
-- Making copies of necessary system libs will pass them on as upvalues;
-- only the first state doing "require 'lanes'" will need to have 'string'
-- and 'table' visible.
--
local function WR(str)
io.stderr:write( str.."\n" )
end
local function DUMP( tbl )
if not tbl then return end
local str=""
for k,v in pairs(tbl) do
str= str..k.."="..tostring(v).."\n"
end
WR(str)
end
---=== Laning ===---
-- lane_h[1..n]: lane results, same as via 'lane_h:join()'
-- lane_h[0]: can be read to make sure a thread has finished (always gives 'true')
-- lane_h[-1]: error message, without propagating the error
--
-- Reading a Lane result (or [0]) propagates a possible error in the lane
-- (and execution does not return). Cancelled lanes give 'nil' values.
--
-- lane_h.state: "pending"/"running"/"waiting"/"done"/"error"/"cancelled"
--
-- Note: Would be great to be able to have '__ipairs' metamethod, that gets
-- called by 'ipairs()' function to custom iterate objects. We'd use it
-- for making sure a lane has ended (results are available); not requiring
-- the user to precede a loop by explicit 'h[0]' or 'h:join()'.
--
-- Or, even better, 'ipairs()' should start valuing '__index' instead
-- of using raw reads that bypass it.
--
-----
-- lanes.gen( [libs_str|opt_tbl [, ...],] lane_func ) ( [...] ) -> h
--
-- 'libs': nil: no libraries available (default)
-- "": only base library ('assert', 'print', 'unpack' etc.)
-- "math,os": math + os + base libraries (named ones + base)
-- "*": all standard libraries available
--
-- 'opt': .priority: int (-2..+2) smaller is lower priority (0 = default)
--
-- .cancelstep: bool | uint
-- false: cancellation check only at pending Linda operations
-- (send/receive) so no runtime performance penalty (default)
-- true: adequate cancellation check (same as 100)
-- >0: cancellation check every x Lua lines (small number= faster
-- reaction but more performance overhead)
--
-- .globals: table of globals to set for a new thread (passed by value)
--
-- .required: table of packages to require
-- ... (more options may be introduced later) ...
--
-- Calling with a function parameter ('lane_func') ends the string/table
-- modifiers, and prepares a lane generator. One can either finish here,
-- and call the generator later (maybe multiple times, with different parameters)
-- or add on actual thread arguments to also ignite the thread on the same call.
local valid_libs=
{
["package"] = true,
["table"] = true,
["io"] = true,
["os"] = true,
["string"] = true,
["math"] = true,
["debug"] = true,
["bit32"] = true, -- Lua 5.2 only, ignored silently under 5.1
--
["base"] = true,
["coroutine"] = true, -- part of "base" in Lua 5.1
["lanes.core"] = true
}
-- PUBLIC LANES API
local function gen( ... )
local opt= {}
local libs= nil
local lev= 2 -- level for errors
local n= select('#',...)
if n==0 then
error( "No parameters!" )
end
for i=1,n-1 do
local v= select(i,...)
if type(v)=="string" then
libs= libs and libs..","..v or v
elseif type(v)=="table" then
for k,vv in pairs(v) do
opt[k]= vv
end
elseif v==nil then
-- skip
else
error( "Bad parameter: "..tostring(v) )
end
end
local func= select(n,...)
local functype = type(func)
if functype ~= "function" and functype ~= "string" then
error( "Last parameter not function or string: "..tostring(func))
end
-- Check 'libs' already here, so the error goes in the right place
-- (otherwise will be noticed only once the generator is called)
-- "*" is a special case that doesn't require individual checking
--
if libs and libs ~= "*" then
local found = {}
-- check that the caller only provides reserved library names
for s in string_gmatch(libs, "[%a%d.]+") do
if not valid_libs[s] then
error( "Bad library name: " .. s)
else
found[s] = (found[s] or 0) + 1
if found[s] > 1 then
error( "libs specification contains '" .. s .. "' more than once")
end
end
end
end
local prio, cs, g_tbl, package_tbl, required
for k,v in pairs(opt) do
if k=="priority" then prio= v
elseif k=="cancelstep" then
cs = (v==true) and 100 or
(v==false) and 0 or
type(v)=="number" and v or
error( "Bad cancelstep: "..tostring(v), lev )
elseif k=="globals" then g_tbl= v
elseif k=="package" then
package_tbl = (type( v) == "table") and v or error( "Bad package: " .. tostring( v), lev)
elseif k=="required" then
required= (type( v) == "table") and v or error( "Bad 'required' option: expecting table, got " .. type( v), lev)
--..
elseif k==1 then error( "unkeyed option: ".. tostring(v), lev )
else error( "Bad option: ".. tostring(k), lev )
end
end
if not package_tbl then package_tbl = package end
-- Lane generator
--
return function(...)
return thread_new( func, libs, _params.on_state_create, cs, prio, g_tbl, package_tbl, required, ...) -- args
end
end
---=== Lindas ===---
-- We let the C code attach methods to userdata directly
-----
-- lanes.linda(["name"]) -> linda_ud
--
-- PUBLIC LANES API
local linda = core.linda
---=== Timers ===---
-- PUBLIC LANES API
local timer = function() error "timers are not active" end
local timer_lane = nil
local timers = timer
if _params.with_timers ~= false then
local timer_gateway = assert( core.timer_gateway)
--
-- On first 'require "lanes"', a timer lane is spawned that will maintain
-- timer tables and sleep in between the timer events. All interaction with
-- the timer lane happens via a 'timer_gateway' Linda, which is common to
-- all that 'require "lanes"'.
--
-- Linda protocol to timer lane:
--
-- TGW_KEY: linda_h, key, [wakeup_at_secs], [repeat_secs]
--
local TGW_KEY= "(timer control)" -- the key does not matter, a 'weird' key may help debugging
local TGW_QUERY, TGW_REPLY = "(timer query)", "(timer reply)"
local first_time_key= "first time"
local first_time= timer_gateway:get(first_time_key) == nil
timer_gateway:set(first_time_key,true)
--
-- Timer lane; initialize only on the first 'require "lanes"' instance (which naturally
-- has 'table' always declared)
--
if first_time then
-----
-- Snore loop (run as a lane on the background)
--
-- High priority, to get trustworthy timings.
--
-- We let the timer lane be a "free running" thread; no handle to it
-- remains.
--
local timer_body = function()
-- require lanes.core inside the timer body to prevent pulling now_secs() through an uvpvalue
local core = require "lanes.core"
--
-- { [deep_linda_lightuserdata]= { [deep_linda_lightuserdata]=linda_h,
-- [key]= { wakeup_secs [,period_secs] } [, ...] },
-- }
--
-- Collection of all running timers, indexed with linda's & key.
--
-- Note that we need to use the deep lightuserdata identifiers, instead
-- of 'linda_h' themselves as table indices. Otherwise, we'd get multiple
-- entries for the same timer.
--
-- The 'hidden' reference to Linda proxy is used in 'check_timers()' but
-- also important to keep the Linda alive, even if all outside world threw
-- away pointers to it (which would ruin uniqueness of the deep pointer).
-- Now we're safe.
--
local collection = {}
local table_insert = assert( table.insert)
local get_timers = function()
local r = {}
for deep, t in pairs( collection) do
-- WR( tostring( deep))
local l = t[deep]
for key, timer_data in pairs( t) do
if key ~= deep then
table_insert( r, {l, key, timer_data})
end
end
end
return r
end -- get_timers()
--
-- set_timer( linda_h, key [,wakeup_at_secs [,period_secs]] )
--
local set_timer = function( linda, key, wakeup_at, period)
assert( wakeup_at == nil or wakeup_at > 0.0)
assert( period == nil or period > 0.0)
local linda_deep = linda:deep()
assert( linda_deep)
-- Find or make a lookup for this timer
--
local t1 = collection[linda_deep]
if not t1 then
t1 = { [linda_deep] = linda} -- proxy to use the Linda
collection[linda_deep] = t1
end
if wakeup_at == nil then
-- Clear the timer
--
t1[key]= nil
-- Remove empty tables from collection; speeds timer checks and
-- lets our 'safety reference' proxy be gc:ed as well.
--
local empty = true
for k, _ in pairs( t1) do
if k ~= linda_deep then
empty = false
break
end
end
if empty then
collection[linda_deep] = nil
end
-- Note: any unread timer value is left at 'linda[key]' intensionally;
-- clearing a timer just stops it.
else
-- New timer or changing the timings
--
local t2 = t1[key]
if not t2 then
t2= {}
t1[key]= t2
end
t2[1] = wakeup_at
t2[2] = period -- can be 'nil'
end
end -- set_timer()
local now_secs = core.now_secs
assert( type( now_secs) == "function")
-----
-- [next_wakeup_at]= check_timers()
-- Check timers, and wake up the ones expired (if any)
-- Returns the closest upcoming (remaining) wakeup time (or 'nil' if none).
local check_timers = function()
local now = now_secs()
local next_wakeup
for linda_deep,t1 in pairs(collection) do
for key,t2 in pairs(t1) do
--
if key==linda_deep then
-- no 'continue' in Lua :/
else
-- 't2': { wakeup_at_secs [,period_secs] }
--
local wakeup_at= t2[1]
local period= t2[2] -- may be 'nil'
if wakeup_at <= now then
local linda= t1[linda_deep]
assert(linda)
linda:set( key, now )
-- 'pairs()' allows the values to be modified (and even
-- removed) as far as keys are not touched
if not period then
-- one-time timer; gone
--
t1[key]= nil
wakeup_at= nil -- no 'continue' in Lua :/
else
-- repeating timer; find next wakeup (may jump multiple repeats)
--
repeat
wakeup_at= wakeup_at+period
until wakeup_at > now
t2[1]= wakeup_at
end
end
if wakeup_at and ((not next_wakeup) or (wakeup_at < next_wakeup)) then
next_wakeup= wakeup_at
end
end
end -- t2 loop
end -- t1 loop
return next_wakeup -- may be 'nil'
end -- check_timers()
local timer_gateway_batched = timer_gateway.batched
set_debug_threadname( "LanesTimer")
set_finalizer( function( err, stk)
if err and type( err) ~= "userdata" then
WR( "LanesTimer error: "..tostring(err))
--elseif type( err) == "userdata" then
-- WR( "LanesTimer after cancel" )
--else
-- WR("LanesTimer finalized")
end
end)
while true do
local next_wakeup = check_timers()
-- Sleep until next timer to wake up, or a set/clear command
--
local secs
if next_wakeup then
secs = next_wakeup - now_secs()
if secs < 0 then secs = 0 end
end
local key, what = timer_gateway:receive( secs, TGW_KEY, TGW_QUERY)
if key == TGW_KEY then
assert( getmetatable( what) == "Linda") -- 'what' should be a linda on which the client sets a timer
local _, key, wakeup_at, period = timer_gateway:receive( 0, timer_gateway_batched, TGW_KEY, 3)
assert( key)
set_timer( what, key, wakeup_at, period and period > 0 and period or nil)
elseif key == TGW_QUERY then
if what == "get_timers" then
timer_gateway:send( TGW_REPLY, get_timers())
else
timer_gateway:send( TGW_REPLY, "unknown query " .. what)
end
--elseif secs == nil then -- got no value while block-waiting?
-- WR( "timer lane: no linda, aborted?")
end
end
end -- timer_body()
timer_lane = gen( "*", { package= {}, priority = max_prio}, timer_body)() -- "*" instead of "io,package" for LuaJIT compatibility...
end -- first_time
-----
-- = timer( linda_h, key_val, date_tbl|first_secs [,period_secs] )
--
-- PUBLIC LANES API
timer = function( linda, key, a, period )
if getmetatable( linda) ~= "Linda" then
error "expecting a Linda"
end
if a == 0.0 then
-- Caller expects to get current time stamp in Linda, on return
-- (like the timer had expired instantly); it would be good to set this
-- as late as possible (to give most current time) but also we want it
-- to precede any possible timers that might start striking.
--
linda:set( key, core.now_secs())
if not period or period==0.0 then
timer_gateway:send( TGW_KEY, linda, key, nil, nil ) -- clear the timer
return -- nothing more to do
end
a= period
end
local wakeup_at= type(a)=="table" and core.wakeup_conv(a) -- given point of time
or (a and core.now_secs()+a or nil)
-- queue to timer
--
timer_gateway:send( TGW_KEY, linda, key, wakeup_at, period )
end
-----
-- {[{linda, slot, when, period}[,...]]} = timers()
--
-- PUBLIC LANES API
timers = function()
timer_gateway:send( TGW_QUERY, "get_timers")
local _, r = timer_gateway:receive( TGW_REPLY)
return r
end
end -- _params.with_timers
---=== Lock & atomic generators ===---
-- These functions are just surface sugar, but make solutions easier to read.
-- Not many applications should even need explicit locks or atomic counters.
--
-- lock_f= lanes.genlock( linda_h, key [,N_uint=1] )
--
-- = lock_f( +M ) -- acquire M
-- ...locked...
-- = lock_f( -M ) -- release M
--
-- Returns an access function that allows 'N' simultaneous entries between
-- acquire (+M) and release (-M). For binary locks, use M==1.
--
-- PUBLIC LANES API
local function genlock( linda, key, N )
linda:limit(key,N)
linda:set(key,nil) -- clears existing data
--
-- [true [, ...]= trues(uint)
--
local function trues(n)
if n>0 then return true,trues(n-1) end
end
return
function(M)
if M>0 then
-- 'nil' timeout allows 'key' to be numeric
linda:send( nil, key, trues(M) ) -- suspends until been able to push them
else
for i=1,-M do
linda:receive( key )
end
end
end
end
--
-- atomic_f= lanes.genatomic( linda_h, key [,initial_num=0.0] )
--
-- int= atomic_f( [diff_num=1.0] )
--
-- Returns an access function that allows atomic increment/decrement of the
-- number in 'key'.
--
-- PUBLIC LANES API
local function genatomic( linda, key, initial_val )
linda:limit(key,2) -- value [,true]
linda:set(key,initial_val or 0.0) -- clears existing data (also queue)
return
function(diff)
-- 'nil' allows 'key' to be numeric
linda:send( nil, key, true ) -- suspends until our 'true' is in
local val= linda:get(key) + (diff or 1.0)
linda:set( key, val ) -- releases the lock, by emptying queue
return val
end
end
-- activate full interface
lanes.require = core.require
lanes.gen = gen
lanes.linda = core.linda
lanes.cancel_error = core.cancel_error
lanes.nameof = core.nameof
lanes.threads = (_params.track_lanes and core.threads) and core.threads or function() error "lane tracking is not available" end
lanes.timer = timer
lanes.timer_lane = timer_lane
lanes.timers = timers
lanes.genlock = genlock
lanes.now_secs = core.now_secs
lanes.genatomic = genatomic
-- from now on, calling configure does nothing but checking that we don't call it with parameters that changed compared to the first invocation
lanes.configure = function( _params2)
_params2 = params_checker( _params2 or _params)
for key, value2 in pairs( _params2) do
local value = _params[key]
if value2 ~= value then
error( "mismatched configuration: " .. key .. " is " .. tostring( value2) .. " instead of " .. tostring( value))
end
end
return lanes
end
return lanes
end -- lanes.configure
--the end
return lanes