source: extensions/gsdl-video/trunk/installed/cmdline/lib/ruby/1.8/shell/process-controller.rb@ 18425

#
#   shell/process-controller.rb - 
#       $Release Version: 0.6.0 $
#       $Revision: 12008 $
#       $Date: 2007-03-06 19:12:12 +0900 (Tue, 06 Mar 2007) $
#       by Keiju ISHITSUKA(Nihon Rational Software Co.,Ltd)
#
# --
#
#   
#

require "mutex_m"
require "monitor"
require "sync"

class Shell
  class ProcessController

    @ProcessControllers = {}
    @ProcessControllers.extend Mutex_m

    class<<self

      def process_controllers_exclusive
    begin
      @ProcessControllers.lock unless Thread.critical 
      yield
    ensure
      @ProcessControllers.unlock unless Thread.critical 
    end
      end

      def activate(pc)
    process_controllers_exclusive do
      @ProcessControllers[pc] ||= 0
      @ProcessControllers[pc] += 1
    end
      end

      def inactivate(pc)
    process_controllers_exclusive do
      if @ProcessControllers[pc]
        if (@ProcessControllers[pc] -= 1) == 0
          @ProcessControllers.delete(pc)
        end
      end
    end
      end

      def each_active_object
    process_controllers_exclusive do
      for ref in @ProcessControllers.keys
        yield ref
      end
    end
      end
    end

    def initialize(shell)
      @shell = shell
      @waiting_jobs = []
      @active_jobs = []
      @jobs_sync = Sync.new

      @job_monitor = Mutex.new
      @job_condition = ConditionVariable.new
    end

    def jobs
      jobs = []
      @jobs_sync.synchronize(:SH) do
    jobs.concat @waiting_jobs
    jobs.concat @active_jobs
      end
      jobs
    end

    def active_jobs
      @active_jobs
    end

    def waiting_jobs
      @waiting_jobs
    end
    
    def jobs_exist?
      @jobs_sync.synchronize(:SH) do
    @active_jobs.empty? or @waiting_jobs.empty?
      end
    end

    def active_jobs_exist?
      @jobs_sync.synchronize(:SH) do
    @active_jobs.empty?
      end
    end

    def waiting_jobs_exist?
      @jobs_sync.synchronize(:SH) do
    @waiting_jobs.empty?
      end
    end

    # schedule a command
    def add_schedule(command)
      @jobs_sync.synchronize(:EX) do
    ProcessController.activate(self)
    if @active_jobs.empty?
      start_job command
    else
      @waiting_jobs.push(command)
    end
      end
    end

    # start a job
    def start_job(command = nil)
      @jobs_sync.synchronize(:EX) do
    if command
      return if command.active?
      @waiting_jobs.delete command
    else
      command = @waiting_jobs.shift
      return unless command
    end
    @active_jobs.push command
    command.start

    # start all jobs that input from the job
    for job in @waiting_jobs
      start_job(job) if job.input == command
    end
      end
    end

    def waiting_job?(job)
      @jobs_sync.synchronize(:SH) do
    @waiting_jobs.include?(job)
      end
    end

    def active_job?(job)
      @jobs_sync.synchronize(:SH) do
    @active_jobs.include?(job)
      end
    end

    # terminate a job
    def terminate_job(command)
      @jobs_sync.synchronize(:EX) do
    @active_jobs.delete command
    ProcessController.inactivate(self)
    if @active_jobs.empty?
      start_job
    end
      end
    end

    # kill a job
    def kill_job(sig, command)
      @jobs_sync.synchronize(:SH) do
    if @waiting_jobs.delete command
      ProcessController.inactivate(self)
      return
    elsif @active_jobs.include?(command)
      begin
        r = command.kill(sig)
        ProcessController.inactivate(self)
      rescue
        print "Shell: Warn: $!\n" if @shell.verbose?
        return nil
      end
      @active_jobs.delete command
      r
    end
      end
    end

    # wait for all jobs to terminate
    def wait_all_jobs_execution
      @job_monitor.synchronize do
    begin
      while !jobs.empty?
        @job_condition.wait(@job_monitor)
      end
    ensure
      redo unless jobs.empty?
    end
      end
    end

    # simple fork
    def sfork(command, &block)
      pipe_me_in, pipe_peer_out = IO.pipe
      pipe_peer_in, pipe_me_out = IO.pipe
      Thread.critical = true

      STDOUT.flush
      ProcessController.each_active_object do |pc|
    for jobs in pc.active_jobs
      jobs.flush
    end
      end
      
      pid = fork {
    Thread.critical = true

    Thread.list.each do |th| 
      th.kill unless [Thread.main, Thread.current].include?(th)
    end

    STDIN.reopen(pipe_peer_in)
    STDOUT.reopen(pipe_peer_out)

    ObjectSpace.each_object(IO) do |io| 
      if ![STDIN, STDOUT, STDERR].include?(io)
        io.close unless io.closed?
      end
    end
    yield
      }

      pipe_peer_in.close
      pipe_peer_out.close
      command.notify "job(%name:##{pid}) start", @shell.debug?
      Thread.critical = false

      th = Thread.start {
    Thread.critical = true
    begin
      _pid = nil
      command.notify("job(%id) start to waiting finish.", @shell.debug?)
      Thread.critical = false
      _pid = Process.waitpid(pid, nil)
    rescue Errno::ECHILD
      command.notify "warn: job(%id) was done already waitipd."
      _pid = true
    ensure
      # when the process ends, wait until the command termintes
      if _pid
      else
        command.notify("notice: Process finishing...",
               "wait for Job[%id] to finish.",
               "You can use Shell#transact or Shell#check_point for more safe execution.")
        redo
      end
      Thread.exclusive do
        @job_monitor.synchronize do 
          terminate_job(command)
          @job_condition.signal
          command.notify "job(%id) finish.", @shell.debug?
        end
      end
    end
      }
      return pid, pipe_me_in, pipe_me_out
    end
  end
end