-- -- LANES.LUA -- -- Multithreading and -core support for Lua -- -- Authors: Asko Kauppi -- Benoit Germain -- -- History: see CHANGES -- --[[ =============================================================================== Copyright (C) 2007-10 Asko Kauppi Copyright (C) 2010-13 Benoit Germain 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} 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 return _val and type( _val) == "boolean" or true 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) -- nb_keepers 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 } 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) end local thread_new = assert( core.thread_new) local set_singlethreaded = assert( core.set_singlethreaded) local now_secs = assert( core.now_secs) local wakeup_conv = assert( core.wakeup_conv) local max_prio = assert( core.max_prio) lanes.ABOUT= { author= "Asko Kauppi , Benoit Germain ", 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 } -- 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: " .. tostring( 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 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 local table_remove= assert( table.remove ) local table_insert= assert( table.insert ) -- -- { [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 function get_timers() 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 -- -- set_timer( linda_h, key [,wakeup_at_secs [,period_secs]] ) -- local function set_timer( 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 ----- -- [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 function check_timers() 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 ----- -- 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() 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 gen( "*", { package= {}, priority = max_prio}, timer_body)() -- "*" instead of "io,package" for LuaJIT compatibility... end ----- -- = 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, 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 wakeup_conv(a) -- given point of time or (a and 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.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.timers = timers lanes.genlock = genlock lanes.now_secs = 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