Class OpenWFE::FlowMutex
In: lib/openwfe/expressions/fe_reserve.rb
Parent: Object

A FlowMutex is a process variable (thus serializable) that keeps track of the expressions in a critical section (1!) or waiting for entering it.

The current syncrhonization scheme is 1 thread mutex for all the FlowMutex. Shouldn‘t be too costly and the operations under sync are quite tiny.

Methods

new   register   release   synchronize  

Attributes

feis  [RW] 
mutex_name  [RW] 

Public Class methods

new(mutex_name)

[Source]

     # File lib/openwfe/expressions/fe_reserve.rb, line 149
149:         def initialize (mutex_name)
150: 
151:             @mutex_name = mutex_name
152:             @feis = []
153:         end
synchronize(&block)

Used by the ReserveExpression when looking up for a FlowMutex and registering into it.

[Source]

     # File lib/openwfe/expressions/fe_reserve.rb, line 201
201:         def self.synchronize (&block)
202: 
203:             @@class_mutex.synchronize do
204: 
205:                 block.call
206:             end
207:         end

Public Instance methods

register(fexp, workitem)

[Source]

     # File lib/openwfe/expressions/fe_reserve.rb, line 155
155:         def register (fexp, workitem)
156: 
157:             @feis << fexp.fei
158: 
159:             fexp.set_variable @mutex_name, self
160: 
161:             if @feis.size == 1
162:                 #
163:                 # immediately let the expression enter the critical section
164:                 #
165:                 fexp.store_itself
166:                 fexp.enter workitem
167:             else
168:                 #
169:                 # later...
170:                 #
171:                 fexp.applied_workitem = workitem
172:                 fexp.store_itself
173:             end
174:         end
release(releaser)

[Source]

     # File lib/openwfe/expressions/fe_reserve.rb, line 176
176:         def release (releaser)
177: 
178:             next_fei = nil
179: 
180:             @@class_mutex.synchronize do
181: 
182:                 current_fei = @feis.delete_at 0
183: 
184:                 releaser.set_variable @mutex_name, self
185: 
186:                 log.warn "release() BAD! c:#{current_fei} r:#{releaser.fei}" \
187:                     if releaser.fei != current_fei
188: 
189:                 next_fei = @feis.first
190:             end
191: 
192:             return unless next_fei
193: 
194:             releaser.get_expression_pool.fetch_expression(next_fei).enter
195:         end

[Validate]