#
#--
# Copyright (c) 2006-2007, Nicolas Modryzk and 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 
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# 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"
#
# Nicolas Modrzyk at openwfe.org
# John Mettraux at openwfe.org
#

require 'fileutils'

require 'openwfe/service'
require 'openwfe/util/lru_cache'
require 'openwfe/flowexpressionid'

module OpenWFE
    
    #
    # Create a composite expression storage.
    # This will take parameters from the application context to create 
    # the resulting composite storage
    class CompositeExpressionStorage 
        include ServiceMixin
        
        attr_accessor \
        :persistence, \
        :cache, \
        :journal
        
        def initialize (serviceName, applicationContext)
            
            service_init(serviceName, applicationContext)
            
            @cache = @application_context[:cached_expression_storage]
            @journal = @application_context[:journalized_expression_storage]
            @persistence = @application_context[:file_expression_storage]
        end
        
        #
        # call the add method for each registered storage
        #
        def []= (fei, flowExpression)
            @journal[fei] = flowExpression if @journal
            @cache[fei] = flowExpression if @cache
            @persistence[fei] = flowExpression
        end
        
        #
        # remove the expressionid from each registered storage
        #
        def delete (fei)
            @journal.delete(fei) if @journal
            @cache.delete(fei) if @cache
            @persistence.delete(fei)
        end
        
        #
        # slightly different method. Try to get the value from the cache storage if one
        # if not retrieve it, and then add it to the cache.
        def [] (fei)
            return @cache[fei] if @cache
            flow_expression = @persistence[fei]
            @cache[fei] = flow_expression if @cache
            return flow_expression
        end
    end
        
     #
     # implementation of a LRU caching storage.
    class LruCachedExpressionStorage
        include ServiceMixin
        
        DEFAULT_LRU_SIZE = 10
        
        def initialize (service_name, application_context)
            service_init(service_name, application_context)
            size = if (@application_context) 
                @application_context[:lru_storage_size] 
            else 
                DEFAULT_LRU_SIZE 
            end
            @cache = LRUCache.new(size)
        end
        
        def []= (fei, flowExpression)
            @cache[fei]=flowExpression
        end
        
        #
        # interface method to remove an entry for the given expression_id
        #
        def delete (fei)
            @cache.delete(fei)
        end
        
        #
        # check if the value is in the cache
        def is_in_cache?(fei)
            @cache.include?(fei)
        end
        alias has_key? is_in_cache? 
        
        #
        # interface method, return the value associated with the given id, 
        # or nil if not in cache.
        def [] (fei)
            if(@cache.include?(fei))
                return @cache[fei]
            else
                return nil
            end
        end
        
    end
        
    #
    # Memory consuming in-memory storage.
    # No memory limit, puts everything in a Hash
    #
    class InMemoryExpressionStorage < Hash
        include ServiceMixin
        
        def initialize (service_name, application_context)
            service_init(service_name, application_context)
        end

        alias :purge :clear

        def each_of_kind (kind)
            # TODO : implement with a filter
        end
        
        def to_s
            s = "\n\n==== #{self.class} ===="
            each do |k, v|
                s << "\n"
                if v.kind_of?(RawExpression)
                    s << "*raw" 
                else
                    s << "  "
                end
                s << v.to_s
                s << "    key/value mismatch !" if k != v.fei
            end
            s << "\n==== . ====\n"
            return s
        end
        
    end

end