Class: ROC::Lock

Inherits:
Time show all
Defined in:
lib/roc/objects/lock.rb

Instance Attribute Summary

Attributes inherited from Base

#key, #options

Instance Method Summary collapse

Methods inherited from Time

#deserialize, #localtime, #serialize, #to_s, #to_time

Methods included from Types::ScalarType

#clobber, #deserialize, #inspect, #serialize, #setex

Methods included from Types::MethodGenerators

#deserializing_method, #nonserializing_method, #serializing_and_deserializing_method, #serializing_method, #zero_arg_method

Methods inherited from Base

#clobber, delegate_methods, #initialize, #method_missing, #respond_to?, #seed

Methods included from Types::AllTypes

#eval

Constructor Details

This class inherits a constructor from ROC::Base

Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class ROC::Base

Instance Method Details

#lock(expires_time) ⇒ Object 



4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
 
# File 'lib/roc/objects/lock.rb', line 4

def lock(expires_time)
  aquired_lock = false
  if self.setnx(expires_time)
    aquired_lock = true
  else
    locked_until = self.value
    if locked_until.nil? || (locked_until < ::Time.now) ##ttl of 0 is not yet expired
      # only say we got the lock if we manage to update it first
      if self.getset(expires_time) == locked_until
        aquired_lock = true
      end
    end
  end
  aquired_lock
end

#locked? ⇒ Boolean

Returns:

  • (Boolean) 


20
21
22
23
 
# File 'lib/roc/objects/lock.rb', line 20

def locked?
  locked_until = self.value
  !locked_until.nil? && (locked_until >= ::Time.now) ##ttl of 0 is not yet expired
end

#locking_if_necessary(expires_time) ⇒ Object 



40
41
42
43
44
45
46
47
48
49
 
# File 'lib/roc/objects/lock.rb', line 40

def locking_if_necessary(expires_time)
  obtained_lock = self.lock(expires_time)
  begin
    yield
  ensure
    if obtained_lock
      self.unlock
    end
  end      
end

#unlock ⇒ Object 



25
26
27
 
# File 'lib/roc/objects/lock.rb', line 25

def unlock
  self.forget
end

#when_locked(expires_time, poll_ms = 100) ⇒ Object 



29
30
31
32
33
34
35
36
37
38
 
# File 'lib/roc/objects/lock.rb', line 29

def when_locked(expires_time, poll_ms=100)
  until self.lock(expires_time)
    sleep(poll_ms.to_f / 1000)
  end
  begin
    yield
  ensure
    self.unlock
  end
end