#
#--
# Copyright (c) 2006, John Mettraux, OpenWFE.org
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without 
# modification, are permitted provided that the following conditions are met:
# 
# . Redistributions of source code must retain the above copyright notice, this
#   list of conditions and the following disclaimer.  
# 
# . 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.
# 
# . Neither the name of the "OpenWFE" 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 COPYRIGHT OWNER 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.
#++
#
# $Id: definitions.rb 2725 2006-06-02 13:26:32Z jmettraux $
#

#
# "made in Japan"
#
# John Mettraux at openwfe.org
#

require 'monitor'
require 'ru/flowexpression'
require 'ru/rudefinitions'
require 'ru/ruutils'


#
# base expressions like 'sequence' and 'concurrence'
#

module OpenWFEru

    class ConcurrenceExpression < SequenceExpression

        attr_accessor \
            :sync_expression

        def apply (workitem)

            sync = lookup_attribute(A_SYNC, workitem)
            sync = "generic" if not sync

            @sync_expression = \
                get_expression_map().get_sync_class(sync).new(@attributes)

            #threads = []

            @children.each do |child|
                @sync_expression.add_child(child)
            end

            @children.each do |child|
                t = Thread.new do
                    begin
                        get_expression_pool().apply(child, workitem.dup)
                    rescue Exception => e
                        lwarn do 
                            "apply() caught exception in concurrent child\n" + 
                            OpenWFEru::exception_to_s(e)
                        end
                    end
                end

                #threads << t
            end
        end

        def reply (workitem)
            done = @sync_expression.reply(self, workitem)
            reply_to_parent(done) if done
        end
    end

    class SyncExpression
        include Logging, MonitorMixin

        #def initialize()
        #    super()
        #end
    end

    class GenericSyncExpression < SyncExpression

        attr_accessor \
            :remaining_children,
            :count,
            :reply_count,
            :cancel_remaining

        def initialize (attributes)

            super()

            @remaining_children = []
            @reply_count = 0

            @count = determine_count(attributes)
            @cancel_remaining = determine_remaining(attributes)
        end

        def add_child (child)
            @remaining_children << child
        end

        def reply (synchable, workitem)
            synchronize do

                @application_context = synchable.application_context
                    #
                    # ldebug uses the application context

                ldebug { "reply()  #{workitem.lastExpressionId.to_debug_s}" }

                @reply_count = @reply_count + 1

                @remaining_children.delete(workitem.last_expression_id)

                return workitem \
                    if @remaining_children.length <= 0

                if @count > 0 and @reply_count >= @count
                    treat_remaining_children(synchable)
                    return workitem
                end

                return nil
            end
        end

        protected

            def treat_remaining_children (synchable)

                expool = synchable.get_expression_pool

                @remaining_children.each do |child|
                    if @cancel_remaining
                        expool.cancel(child)
                    else
                        expool.remove(child)
                    end
                end
            end

            def determine_remaining (attributes)
                return attributes[A_REMAINING] == REM_CANCEL
            end

            def determine_count (attributes)
                s = attributes[A_COUNT]
                return -1 if not s
                i = s.to_i
                return -1 if i < 1
                return i
            end
    end

    #
    # Merges a workitem (source) into another (target).
    # If inPlace is left to false, a brand new workitem is returned,
    # else the merge occurs directly into the target workitem.
    #
    def merge (wiTarget, wiSource, inPlace=false)

        wiTarget = wiTarget.dup if not inPlace

        wiSource.attributes.each do | k, v |
            wiTarget.attributes[k.dup] = v.dup
        end
    end

end