Open Mash Cross Reference
mash/tcl/common/keepalive.tcl

   # keepalive.tcl --
   #
   #       FIXME: This file needs a description here.
   #
   # Copyright (c) 1997-2002 The Regents of the University of California.
   # All rights reserved.
   #
   # Redistribution and use in source and binary forms, with or without
   # modification, are permitted provided that the following conditions are met:
  #
  # A. Redistributions of source code must retain the above copyright notice,
  #    this list of conditions and the following disclaimer.
  # B. Redistributions in binary form must reproduce the above copyright notice,
  #    this list of conditions and the following disclaimer in the documentation
  #    and/or other materials provided with the distribution.
  # C. Neither the names of the copyright holders nor the names of its
  #    contributors may be used to endorse or promote products derived from this
  #    software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
  # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  # ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
  # ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  # SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  
  Class KeepAlive
  KeepAlive set BeaconInterval_ms 2000
  Class KeepAliveSlave  -superclass KeepAlive
  Class KeepAliveMaster -superclass KeepAlive
  
  
  
  Class KAChannel -superclass CBChannel/Local
  KAChannel set ChannelID_ 1
  Class KASChannel -superclass CBChannel/Local
  Class KAMChannel -superclass CBChannel/Local
  
  
  
  KASChannel instproc init { cb argv0 argv } {
      $self next $cb -id [KAChannel set ChannelID_] -nolisten
      $self set pid_   [pid]
      $self set argv0_ $argv0
      $self set argv_  $argv
  }
  
  
  KASChannel instproc send_alive { } {
      $self instvar pid_ argv0_ argv_
      $self send -apptype KeepAliveMaster alive $pid_ $argv0_ $argv_
  }
  
  
  KASChannel instproc send_dying { } {
      $self instvar pid_
      $self send -apptype KeepAliveMaster dying $pid_
  }
  
  
  KeepAliveSlave instproc init { cb argv0 argv } {
      $self next
      $self instvar cb_ channel_ after_id_
      set cb_ $cb
      set channel_ [$cb_ new_channel KASChannel $argv0 $argv]
      $self send_alive
  }
  
  
  KeepAliveSlave instproc destroy { } {
      $self instvar channel_ cb_ after_id_
      $channel_ send_dying
      $cb_ delete_channel channel_
      after cancel $after_id_
      $self next
  }
  
  
  KeepAliveSlave instproc send_alive { } {
      puts "Sending alive: [pid]"
      $self instvar channel_
      $channel_ send_alive
  
      # schedule the next alive beacon
      $self set after_id_ [after [KeepAlive set BeaconInterval_ms] \
              "$self send_alive"]
  }
  
  
  KeepAliveSlave instproc send_dying { } {
      $self instvar channel_
      $channel_ send_dying
  }
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 KeepAliveMaster instproc init { cb } {
     $self next
     $self instvar cb_ channel_ applist_
     set cb_ $cb
     set channel_ [$cb_ new_channel KAMChannel $self]
     set applist_ ""
     $self periodic_check
 }
 
 
 KeepAliveMaster instproc destroy { } {
     $self instvar channel_ cb_ after_id_
     $cb_ delete_channel channel_
     after cancel $after_id_
     $self next
 }
 
 
 
 
 KeepAliveMaster instproc proc_alive { infoVar pid argv0 argv } {
     puts "Alive: $pid $argv0"
     $self instvar apps_ applist_ after_id_
     if { ![info exists apps_($pid,argv0)] } {
         # this is a new application
         $self new_application $pid $argv0 $argv
         lappend applist_ $pid
     }
     set apps_($pid,argv0)  $argv0
     set apps_($pid,argv)   $argv
     set apps_($pid,status) alive
 }
 
 
 KeepAliveMaster instproc proc_dying { infoVar pid } {
     puts "Got dying $pid"
     $self instvar applist_
     if { [lsearch $applist_ $pid]==-1 } { return }
     $self dismiss $pid
     $self remove  $pid
 }
 
 
 KeepAliveMaster instproc periodic_check { } {
     $self instvar apps_ applist_
     puts "Periodic check [clock seconds]"
     foreach pid $applist_ {
         if { $apps_($pid,status)=="no_beacon" } {
             # I guess this app has died; maybe we should restart it
             $self restart $pid $apps_($pid,argv0) $apps_($pid,argv)
             $self remove $pid
         } else {
             set apps_($pid,status) "no_beacon"
         }
     }
     set after_id_ [after [expr [KeepAlive set BeaconInterval_ms]*2] \
             "$self periodic_check"]
 }
 
 
 KeepAliveMaster instproc remove { pid } {
     $self instvar apps_ applist_
     set idx [lsearch $applist_ $pid]
     if { $idx==-1 } { return }
 
     set applist_ [lreplace $applist_ $idx $idx]
     unset apps_($pid,argv0)
     unset apps_($pid,argv)
     unset apps_($pid,status)
 }
 
 
 
 
 
 
 
 
 #virtual methods
 
 KeepAliveMaster instproc new_application { pid argv0 argv } {
 }
 
 
 KeepAliveMaster instproc restart { pid argv0 argv } {
 }
 
 
 KeepAliveMaster instproc dismiss { pid } {
 }
 
 
 
 
 
 
 KAMChannel instproc init { cb kam } {
     $self next $cb -id [KAChannel set ChannelID_]
     $self register alive "$kam proc_alive"
     $self register dying "$kam proc_dying"
 }