JezK
Edit File: sync.rb
# # sync.rb - 2 phase lock with counter # $Release Version: 1.0$ # $Revision: 32281 $ # by Keiju ISHITSUKA(keiju@ishitsuka.com) # # -- # Sync_m, Synchronizer_m # Usage: # obj.extend(Sync_m) # or # class Foo # include Sync_m # : # end # # Sync_m#sync_mode # Sync_m#sync_locked?, locked? # Sync_m#sync_shared?, shared? # Sync_m#sync_exclusive?, sync_exclusive? # Sync_m#sync_try_lock, try_lock # Sync_m#sync_lock, lock # Sync_m#sync_unlock, unlock # # Sync, Synchronizer: # Usage: # sync = Sync.new # # Sync#mode # Sync#locked? # Sync#shared? # Sync#exclusive? # Sync#try_lock(mode) -- mode = :EX, :SH, :UN # Sync#lock(mode) -- mode = :EX, :SH, :UN # Sync#unlock # Sync#synchronize(mode) {...} # # unless defined? Thread raise "Thread not available for this ruby interpreter" end ## # A module that provides a two-phase lock with a counter. module Sync_m RCS_ID='-$Id: sync.rb 32281 2011-06-29 03:09:34Z drbrain $-' # lock mode UN = :UN SH = :SH EX = :EX # exceptions class Err < StandardError def Err.Fail(*opt) fail self, sprintf(self::Message, *opt) end class UnknownLocker < Err Message = "Thread(%s) not locked." def UnknownLocker.Fail(th) super(th.inspect) end end class LockModeFailer < Err Message = "Unknown lock mode(%s)" def LockModeFailer.Fail(mode) if mode.id2name mode = id2name end super(mode) end end end def Sync_m.define_aliases(cl) cl.module_eval %q{ alias locked? sync_locked? alias shared? sync_shared? alias exclusive? sync_exclusive? alias lock sync_lock alias unlock sync_unlock alias try_lock sync_try_lock alias synchronize sync_synchronize } end def Sync_m.append_features(cl) super # do nothing for Modules # make aliases for Classes. define_aliases(cl) unless cl.instance_of?(Module) self end def Sync_m.extend_object(obj) super obj.sync_extend end def sync_extend unless (defined? locked? and defined? shared? and defined? exclusive? and defined? lock and defined? unlock and defined? try_lock and defined? synchronize) Sync_m.define_aliases(singleton_class) end sync_initialize end # accessing def sync_locked? sync_mode != UN end def sync_shared? sync_mode == SH end def sync_exclusive? sync_mode == EX end # locking methods. def sync_try_lock(mode = EX) return unlock if mode == UN @sync_mutex.synchronize do sync_try_lock_sub(mode) end end def sync_lock(m = EX) return unlock if m == UN while true @sync_mutex.synchronize do if sync_try_lock_sub(m) return self else if sync_sh_locker[Thread.current] sync_upgrade_waiting.push [Thread.current, sync_sh_locker[Thread.current]] sync_sh_locker.delete(Thread.current) else sync_waiting.push Thread.current end @sync_mutex.sleep end end end self end def sync_unlock(m = EX) wakeup_threads = [] @sync_mutex.synchronize do if sync_mode == UN Err::UnknownLocker.Fail(Thread.current) end m = sync_mode if m == EX and sync_mode == SH runnable = false case m when UN Err::UnknownLocker.Fail(Thread.current) when EX if sync_ex_locker == Thread.current if (self.sync_ex_count = sync_ex_count - 1) == 0 self.sync_ex_locker = nil if sync_sh_locker.include?(Thread.current) self.sync_mode = SH else self.sync_mode = UN end runnable = true end else Err::UnknownLocker.Fail(Thread.current) end when SH if (count = sync_sh_locker[Thread.current]).nil? Err::UnknownLocker.Fail(Thread.current) else if (sync_sh_locker[Thread.current] = count - 1) == 0 sync_sh_locker.delete(Thread.current) if sync_sh_locker.empty? and sync_ex_count == 0 self.sync_mode = UN runnable = true end end end end if runnable if sync_upgrade_waiting.size > 0 th, count = sync_upgrade_waiting.shift sync_sh_locker[th] = count th.wakeup wakeup_threads.push th else wait = sync_waiting self.sync_waiting = [] for th in wait th.wakeup wakeup_threads.push th end end end end for th in wakeup_threads th.run end self end def sync_synchronize(mode = EX) sync_lock(mode) begin yield ensure sync_unlock end end attr_accessor :sync_mode attr_accessor :sync_waiting attr_accessor :sync_upgrade_waiting attr_accessor :sync_sh_locker attr_accessor :sync_ex_locker attr_accessor :sync_ex_count def sync_inspect sync_iv = instance_variables.select{|iv| /^@sync_/ =~ iv.id2name}.collect{|iv| iv.id2name + '=' + instance_eval(iv.id2name).inspect}.join(",") print "<#{self.class}.extend Sync_m: #{inspect}, <Sync_m: #{sync_iv}>" end private def sync_initialize @sync_mode = UN @sync_waiting = [] @sync_upgrade_waiting = [] @sync_sh_locker = Hash.new @sync_ex_locker = nil @sync_ex_count = 0 @sync_mutex = Mutex.new end def initialize(*args) super sync_initialize end def sync_try_lock_sub(m) case m when SH case sync_mode when UN self.sync_mode = m sync_sh_locker[Thread.current] = 1 ret = true when SH count = 0 unless count = sync_sh_locker[Thread.current] sync_sh_locker[Thread.current] = count + 1 ret = true when EX # in EX mode, lock will upgrade to EX lock if sync_ex_locker == Thread.current self.sync_ex_count = sync_ex_count + 1 ret = true else ret = false end end when EX if sync_mode == UN or sync_mode == SH && sync_sh_locker.size == 1 && sync_sh_locker.include?(Thread.current) self.sync_mode = m self.sync_ex_locker = Thread.current self.sync_ex_count = 1 ret = true elsif sync_mode == EX && sync_ex_locker == Thread.current self.sync_ex_count = sync_ex_count + 1 ret = true else ret = false end else Err::LockModeFailer.Fail mode end return ret end end ## # An alias for Sync_m from sync.rb Synchronizer_m = Sync_m ## # A class that providesa two-phase lock with a counter. See Sync_m for # details. class Sync include Sync_m end ## # An alias for Sync from sync.rb. See Sync_m for details. Synchronizer = Sync