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+#
+# sync.rb - カウント付2-フェーズロッククラス
+# $Release Version: 0.1$
+# $Revision: 1.3 $
+# $Date: 1997/08/18 07:17:08 $
+# by Keiju ISHITSUKA
+#
+# --
+# Usage:
+# Sync_m, Synchronizer_m
+#
+# 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, Synchronicer:
+# include Sync_m
+#
+# 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
+ fail "Thread not available for this ruby interpreter"
+end
+
+require "finalize.rb"
+
+module Sync_m
+ RCS_ID='-$Header: /home/keiju/var/src/var.lib/ruby/RCS/sync.rb,v 1.3 1997/08/18 07:17:08 keiju Exp keiju $-'
+
+ UN = :UN
+ SH = :SH
+ EX = :EX
+
+ class Err < Exception
+ 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.extend_object(obj)
+ if Fixnum === obj or TRUE === obj or FALSE === obj or nil == obj
+ raise TypeError, "Sync_m can't extend to this class(#{obj.type})"
+ else
+ begin
+ eval "class << obj
+ @sync_locked
+ end"
+ obj.extend(For_primitive_object)
+ rescue TypeError
+ obj.extend(For_general_object)
+ end
+ end
+ end
+
+ def sync_extended
+ unless (defined? locked? and
+ defined? shared? and
+ defined? exclusive? and
+ defined? lock and
+ defined? unlock and
+ defined? try_lock and
+ defined? synchronize)
+ eval "class << self
+ alias locked? sync_locked?
+ alias shared? sync_shared?
+ alias excluive? sync_exclusive?
+ alias lock sync_lock
+ alias unlock sync_unlock
+ alias try_lock sync_try_lock
+ alias synchronize sync_synchronize
+ end"
+ end
+ end
+
+ def sync_locked?
+ sync_mode != UN
+ end
+
+ def sync_shared?
+ sync_mode == SH
+ end
+
+ def sync_exclusive?
+ sync_mode == EX
+ end
+
+ def sync_try_lock(mode = EX)
+ return unlock if sync_mode == UN
+
+ Thread.critical = TRUE
+ ret = sync_try_lock_sub(sync_mode)
+ Thread.critical = FALSE
+ ret
+ end
+
+ def sync_lock(m = EX)
+ return unlock if m == UN
+
+ until (Thread.critical = TRUE; sync_try_lock_sub(m))
+ 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
+ Thread.stop
+ end
+ Thread.critical = FALSE
+ self
+ end
+
+ def sync_unlock(m = EX)
+ Thread.critical = TRUE
+ if sync_mode == UN
+ Thread.critical = FALSE
+ Err::UnknownLocker.Fail(Thread.current)
+ end
+
+ m = sync_mode if m == EX and sync_mode == SH
+
+ runnable = FALSE
+ case m
+ when UN
+ Thread.critical = FALSE
+ 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
+ for k, v in sync_upgrade_waiting
+ sync_sh_locker[k] = v
+ end
+ wait = sync_upgrade_waiting
+ self.sync_upgrade_waiting = []
+ Thread.critical = FALSE
+
+ for w, v in wait
+ w.run
+ end
+ else
+ wait = sync_waiting
+ self.sync_waiting = []
+ Thread.critical = FALSE
+ for w in wait
+ w.run
+ end
+ end
+ end
+
+ Thread.critical = FALSE
+ self
+ 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
+ # 既に, モードがEXである時は, 必ずEXロックとなる.
+ 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
+ Thread.critical = FALSE
+ Err::LockModeFailer.Fail mode
+ end
+ return ret
+ end
+ private :sync_try_lock_sub
+
+ def sync_synchronize(mode = EX)
+ begin
+ sync_lock(mode)
+ yield
+ ensure
+ sync_unlock
+ end
+ end
+
+ module For_primitive_object
+ include Sync_m
+
+ LockState = Struct.new("LockState",
+ :mode,
+ :waiting,
+ :upgrade_waiting,
+ :sh_locker,
+ :ex_locker,
+ :ex_count)
+
+ Sync_Locked = Hash.new
+
+ def For_primitive_object.extend_object(obj)
+ super
+ obj.sync_extended
+ Finalizer.add(obj, For_primitive_object, :sync_finalize)
+ end
+
+ def sync_extended
+ super
+ Sync_Locked[id] = LockState.new(UN, [], [], Hash.new, nil, 0 )
+ end
+
+ def sync_finalize
+ wait = Sync_Locked.delete(id)
+ # waiting == [] ときだけ GCされるので, 待ち行列の解放は意味がない.
+ end
+
+ def sync_mode
+ Sync_Locked[id].mode
+ end
+ def sync_mode=(value)
+ Sync_Locked[id].mode = value
+ end
+
+ def sync_waiting
+ Sync_Locked[id].waiting
+ end
+ def sync_waiting=(v)
+ Sync_Locked[id].waiting = v
+ end
+
+ def sync_upgrade_waiting
+ Sync_Locked[id].upgrade_waiting
+ end
+ def sync_upgrade_waiting=(v)
+ Sync_Locked[id].upgrade_waiting = v
+ end
+
+ def sync_sh_locker
+ Sync_Locked[id].sh_locker
+ end
+ def sync_sh_locker=(v)
+ Sync_Locked[id].sh_locker = v
+ end
+
+ def sync_ex_locker
+ Sync_Locked[id].ex_locker
+ end
+ def sync_ex_locker=(value)
+ Sync_Locked[id].ex_locker = value
+ end
+
+ def sync_ex_count
+ Sync_Locked[id].ex_count
+ end
+ def sync_ex_count=(value)
+ Sync_Locked[id].ex_count = value
+ end
+
+ end
+
+ module For_general_object
+ include Sync_m
+
+ def For_general_object.extend_object(obj)
+ super
+ obj.sync_extended
+ end
+
+ def sync_extended
+ super
+ @sync_mode = UN
+ @sync_waiting = []
+ @sync_upgrade_waiting = []
+ @sync_sh_locker = Hash.new
+ @sync_ex_locker = nil
+ @sync_ex_count = 0
+ end
+
+ attr :sync_mode, TRUE
+
+ attr :sync_waiting, TRUE
+ attr :sync_upgrade_waiting, TRUE
+ attr :sync_sh_locker, TRUE
+ attr :sync_ex_locker, TRUE
+ attr :sync_ex_count, TRUE
+
+ end
+end
+Synchronizer_m = Sync_m
+
+class Sync
+ include Sync_m::For_general_object
+
+ def initialize
+ sync_extended
+ end
+
+end
+Synchronizer = Sync