diff options
Diffstat (limited to 'trunk/lib/sync.rb')
-rw-r--r-- | trunk/lib/sync.rb | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/trunk/lib/sync.rb b/trunk/lib/sync.rb new file mode 100644 index 0000000000..22f160f290 --- /dev/null +++ b/trunk/lib/sync.rb @@ -0,0 +1,307 @@ +# +# sync.rb - 2 phase lock with counter +# $Release Version: 1.0$ +# $Revision$ +# 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 + +module Sync_m + RCS_ID='-$Header$-' + + # 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(class<<self;self;end) + 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 sync_mode == UN + @sync_mutex.synchronize do + ret = sync_try_lock_sub(sync_mode) + end + ret + 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 +Synchronizer_m = Sync_m + +class Sync + include Sync_m +end +Synchronizer = Sync |