Initial revision

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@2 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/sync.rb

@@ -0,0 +1,376 @@
+#
+#   sync.rb - カウント付2-フェーズロッククラス
+#   	$Release Version: 0.1$
+#   	$Revision$
+#   	$Date$
+#   	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='-$Header$-'
+  
+  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