Checkout of Instiki Trunk 1/21/2007.

lib/wiki_content.rb

@@ -0,0 +1,202 @@
+require 'cgi'
+require_dependency 'chunks/engines'
+require_dependency 'chunks/category'
+require_dependency 'chunks/include'
+require_dependency 'chunks/wiki'
+require_dependency 'chunks/literal'
+require_dependency 'chunks/uri'
+require_dependency 'chunks/nowiki'
+
+# Wiki content is just a string that can process itself with a chain of
+# actions. The actions can modify wiki content so that certain parts of
+# it are protected from being rendered by later actions.
+#
+# When wiki content is rendered, it can be interrogated to find out 
+# which chunks were rendered. This means things like categories, wiki 
+# links, can be determined.
+#
+# Exactly how wiki content is rendered is determined by a number of 
+# settings that are optionally passed in to a constructor. The current
+# options are:
+#  * :engine 
+#    => The structural markup engine to use (Textile, Markdown, RDoc)
+#  * :engine_opts
+#    => A list of options to pass to the markup engines (safe modes, etc)
+#  * :pre_engine_actions
+#    => A list of render actions or chunks to be processed before the
+#       markup engine is applied. By default this is:    
+#       Category, Include, URIChunk, WikiChunk::Link, WikiChunk::Word        
+#  * :post_engine_actions
+#    => A list of render actions or chunks to apply after the markup 
+#       engine. By default these are:    
+#       Literal::Pre, Literal::Tags
+#  * :mode
+#    => How should the content be rendered? For normal display (show), 
+#       publishing (:publish) or export (:export)?
+
+module ChunkManager
+  attr_reader :chunks_by_type, :chunks_by_id, :chunks, :chunk_id
+  
+  ACTIVE_CHUNKS = [ NoWiki, Category, WikiChunk::Link, URIChunk, LocalURIChunk, 
+                    WikiChunk::Word ] 
+
+  HIDE_CHUNKS = [ Literal::Pre, Literal::Tags ]
+
+  MASK_RE = { 
+    ACTIVE_CHUNKS => Chunk::Abstract.mask_re(ACTIVE_CHUNKS),
+    HIDE_CHUNKS => Chunk::Abstract.mask_re(HIDE_CHUNKS)
+  }
+  
+  def init_chunk_manager
+    @chunks_by_type = Hash.new
+    Chunk::Abstract::derivatives.each{|chunk_type| 
+      @chunks_by_type[chunk_type] = Array.new 
+    }
+    @chunks_by_id = Hash.new
+    @chunks = []
+    @chunk_id = 0
+  end
+
+  def add_chunk(c)
+      @chunks_by_type[c.class] << c
+      @chunks_by_id[c.object_id] = c
+      @chunks << c
+      @chunk_id += 1
+  end
+
+  def delete_chunk(c)
+    @chunks_by_type[c.class].delete(c)
+    @chunks_by_id.delete(c.object_id)
+    @chunks.delete(c)
+  end
+
+  def merge_chunks(other)
+    other.chunks.each{|c| add_chunk(c)}
+  end
+
+  def scan_chunkid(text)
+    text.scan(MASK_RE[ACTIVE_CHUNKS]){|a| yield a[0] }
+  end
+  
+  def find_chunks(chunk_type)
+    @chunks.select { |chunk| chunk.kind_of?(chunk_type) and chunk.rendered? }
+  end
+
+end
+
+# A simplified version of WikiContent. Useful to avoid recursion problems in 
+# WikiContent.new
+class WikiContentStub < String
+  
+  attr_reader :options
+  include ChunkManager
+  
+  def initialize(content, options)
+    super(content)
+    @options = options
+    init_chunk_manager
+  end
+
+  # Detects the mask strings contained in the text of chunks of type chunk_types
+  # and yields the corresponding chunk ids
+  # example: content = "chunk123categorychunk <pre>chunk456categorychunk</pre>" 
+  # inside_chunks(Literal::Pre) ==> yield 456
+  def inside_chunks(chunk_types)
+    chunk_types.each{|chunk_type|  chunk_type.apply_to(self) }
+    
+    chunk_types.each{|chunk_type| @chunks_by_type[chunk_type].each{|hide_chunk|
+        scan_chunkid(hide_chunk.text){|id| yield id }
+      }
+    } 
+  end
+end
+
+class WikiContent < String
+
+  include ChunkManager
+
+  DEFAULT_OPTS = {
+    :active_chunks       => ACTIVE_CHUNKS,
+    :engine              => Engines::Textile,
+    :engine_opts         => [],
+    :mode                => :show
+  }.freeze
+
+  attr_reader :web, :options, :revision, :not_rendered, :pre_rendered
+
+  # Create a new wiki content string from the given one.
+  # The options are explained at the top of this file.
+  def initialize(revision, url_generator, options = {})
+    @revision = revision
+    @url_generator = url_generator
+    @web = @revision.page.web
+
+    @options = DEFAULT_OPTS.dup.merge(options)
+    @options[:engine] = Engines::MAP[@web.markup] 
+    @options[:engine_opts] = [:filter_html, :filter_styles] if @web.safe_mode?
+    @options[:active_chunks] = (ACTIVE_CHUNKS - [WikiChunk::Word] ) if @web.brackets_only?
+    
+    @not_rendered = @pre_rendered = nil
+    
+    super(@revision.content)
+    init_chunk_manager
+    build_chunks
+    @not_rendered = String.new(self)
+  end
+
+  # Call @web.page_link using current options.
+  def page_link(name, text, link_type)
+    @options[:link_type] = (link_type || :show)
+    @url_generator.make_link(name, @web, text, @options)
+  end
+
+  def build_chunks
+    # create and mask Includes and "active_chunks" chunks
+    Include.apply_to(self)
+    @options[:active_chunks].each{|chunk_type| chunk_type.apply_to(self)}
+
+    # Handle hiding contexts like "pre" and "code" etc..
+    # The markup (textile, rdoc etc) can produce such contexts with its own syntax.
+    # To reveal them, we work on a copy of the content.
+    # The copy is rendered and used to detect the chunks that are inside protecting context  
+    # These chunks are reverted on the original content string.
+
+    copy = WikiContentStub.new(self, @options)
+    @options[:engine].apply_to(copy)
+
+    copy.inside_chunks(HIDE_CHUNKS) do |id|
+      @chunks_by_id[id.to_i].revert
+    end
+  end
+
+  def pre_render!
+    unless @pre_rendered 
+      @chunks_by_type[Include].each{|chunk| chunk.unmask }
+      @pre_rendered = String.new(self)
+    end
+    @pre_rendered 
+  end
+
+  def render!
+    pre_render!
+    @options[:engine].apply_to(self)
+    # unmask in one go. $~[1] is the chunk id
+    gsub!(MASK_RE[ACTIVE_CHUNKS]) do 
+      chunk = @chunks_by_id[$~[1].to_i]
+      if chunk.nil? 
+        # if we match a chunkmask that existed in the original content string
+        # just keep it as it is
+        $~[0]
+      else 
+        chunk.unmask_text 
+      end
+    end
+    self
+  end
+
+  def page_name
+    @revision.page.name
+  end
+
+end
+