Module: Sync_m

Included in:
Sync
Defined in:
lib/sync.rb

Overview

A module that provides a two-phase lock with a counter.

Defined Under Namespace

Classes: Err

Constant Summary collapse

RCS_ID = 
'-$Id: sync.rb 32281 2011-06-29 03:09:34Z drbrain $-'
UN =

lock mode

:UN
SH = 
:SH
EX = 
:EX

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#sync_ex_count ⇒ Object

Returns the value of attribute sync_ex_count



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# File 'lib/sync.rb', line 239

def sync_ex_count
  @sync_ex_count
end

#sync_ex_locker ⇒ Object

Returns the value of attribute sync_ex_locker



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# File 'lib/sync.rb', line 238

def sync_ex_locker
  @sync_ex_locker
end

#sync_mode ⇒ Object

Returns the value of attribute sync_mode



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# File 'lib/sync.rb', line 233

def sync_mode
  @sync_mode
end

#sync_sh_locker ⇒ Object

Returns the value of attribute sync_sh_locker



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# File 'lib/sync.rb', line 237

def sync_sh_locker
  @sync_sh_locker
end

#sync_upgrade_waiting ⇒ Object

Returns the value of attribute sync_upgrade_waiting



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# File 'lib/sync.rb', line 236

def sync_upgrade_waiting
  @sync_upgrade_waiting
end

#sync_waiting ⇒ Object

Returns the value of attribute sync_waiting



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# File 'lib/sync.rb', line 235

def sync_waiting
  @sync_waiting
end

Class Method Details

.append_features(cl) ⇒ Object 



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# File 'lib/sync.rb', line 91

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

.define_aliases(cl) ⇒ Object 



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# File 'lib/sync.rb', line 79

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

.extend_object(obj) ⇒ Object 



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# File 'lib/sync.rb', line 99

def Sync_m.extend_object(obj)
  super
  obj.sync_extend
end

Instance Method Details

#sync_exclusive? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sync.rb', line 126

def sync_exclusive?
  sync_mode == EX
end

#sync_extend ⇒ Object 



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# File 'lib/sync.rb', line 104

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

#sync_inspect ⇒ Object 



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# File 'lib/sync.rb', line 241

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

#sync_lock(m = EX) ⇒ Object 



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# File 'lib/sync.rb', line 138

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

#sync_locked? ⇒ Boolean

accessing

Returns:

  • (Boolean) 


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# File 'lib/sync.rb', line 118

def sync_locked?
  sync_mode != UN
end

#sync_shared? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sync.rb', line 122

def sync_shared?
  sync_mode == SH
end

#sync_synchronize(mode = EX) ⇒ Object 



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# File 'lib/sync.rb', line 224

def sync_synchronize(mode = EX)
  sync_lock(mode)
  begin
    yield
  ensure
    sync_unlock
  end
end

#sync_try_lock(mode = EX) ⇒ Object

locking methods.



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# File 'lib/sync.rb', line 131

def sync_try_lock(mode = EX)
  return unlock if mode == UN
  @sync_mutex.synchronize do
    sync_try_lock_sub(mode)
  end
end

#sync_unlock(m = EX) ⇒ Object 



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# File 'lib/sync.rb', line 159

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