added chunks

lib/chunks/chunk.rb

@@ -0,0 +1,86 @@
+require 'uri/common'
+
+# A chunk is a pattern of text that can be protected
+# and interrogated by a renderer. Each Chunk class has a 
+# +pattern+ that states what sort of text it matches.
+# Chunks are initalized by passing in the result of a
+# match by its pattern. 
+
+module Chunk
+  class Abstract
+
+    # automatically construct the array of derivatives of Chunk::Abstract
+    @derivatives = [] 
+
+    class << self 
+      attr_reader :derivatives 
+    end 
+    
+    def self::inherited( klass ) 
+      Abstract::derivatives << klass 
+    end 
+    
+    # the class name part of the mask strings
+    def self.mask_string
+      self.to_s.delete(':').downcase
+    end
+
+    # a regexp that matches all chunk_types masks
+    def Abstract::mask_re(chunk_types)
+      tmp = chunk_types.map{|klass| klass.mask_string}.join("|")
+      Regexp.new("chunk([0-9a-f]+n\\d+)(#{tmp})chunk")
+    end
+    
+    attr_reader :text, :unmask_text, :unmask_mode
+
+    def initialize(match_data, content) 
+      @text = match_data[0] 
+      @content = content
+      @unmask_mode = :normal
+    end
+
+    # Find all the chunks of the given type in content
+    # Each time the pattern is matched, create a new
+    # chunk for it, and replace the occurance of the chunk
+    # in this content with its mask.
+	def self.apply_to(content)
+	  content.gsub!( self.pattern ) do |match|	
+        new_chunk = self.new($~, content)
+        content.add_chunk(new_chunk)
+        new_chunk.mask
+      end
+    end
+
+    # should contain only [a-z0-9]
+    def mask
+      @mask ||="chunk#{@id}#{self.class.mask_string}chunk"
+    end
+
+    # We should not use object_id because object_id is not guarantied 
+    # to be unique when we restart the wiki (new object ids can equal old ones
+    # that were restored from madeleine storage)  
+    def id
+      @id ||= "#{@content.page_id}n#{@content.chunk_id}"
+    end
+
+    def unmask
+      @content.sub!(mask, @unmask_text)
+    end
+
+    def rendered?
+      @unmask_mode == :normal
+    end
+
+    def escaped?
+      @unmask_mode == :escape
+    end
+
+    def revert
+      @content.sub!(mask, @text)
+      # unregister
+      @content.delete_chunk(self)
+    end
+
+  end
+
+end