view vendor/gems/coderay-1.0.0/lib/coderay/helpers/plugin.rb @ 1082:997f6d7738f7 bug_531

In repo controller entry action, show the page for the file even if it's binary (so user still has access to history etc links). This makes it possible to use the entry action as the default when a file is clicked on

module CodeRay
  
  # = PluginHost
  #
  # A simple subclass/subfolder plugin system.
  #
  # Example:
  #  class Generators
  #    extend PluginHost
  #    plugin_path 'app/generators'
  #  end
  #  
  #  class Generator
  #    extend Plugin
  #    PLUGIN_HOST = Generators
  #  end
  #  
  #  class FancyGenerator < Generator
  #    register_for :fancy
  #  end
  #  
  #  Generators[:fancy]  #-> FancyGenerator
  #  # or
  #  CodeRay.require_plugin 'Generators/fancy'
  #  # or
  #  Generators::Fancy
  module PluginHost
    
    # Raised if Encoders::[] fails because:
    # * a file could not be found
    # * the requested Plugin is not registered
    PluginNotFound = Class.new LoadError
    HostNotFound = Class.new LoadError
    
    PLUGIN_HOSTS = []
    PLUGIN_HOSTS_BY_ID = {}  # dummy hash
    
    # Loads all plugins using list and load.
    def load_all
      for plugin in list
        load plugin
      end
    end
    
    # Returns the Plugin for +id+.
    #
    # Example:
    #  yaml_plugin = MyPluginHost[:yaml]
    def [] id, *args, &blk
      plugin = validate_id(id)
      begin
        plugin = plugin_hash.[] plugin, *args, &blk
      end while plugin.is_a? Symbol
      plugin
    end
    
    alias load []
    
    # Tries to +load+ the missing plugin by translating +const+ to the
    # underscore form (eg. LinesOfCode becomes lines_of_code).
    def const_missing const
      id = const.to_s.
        gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
        gsub(/([a-z\d])([A-Z])/,'\1_\2').
        downcase
      load id
    end
    
    class << self
      
      # Adds the module/class to the PLUGIN_HOSTS list.
      def extended mod
        PLUGIN_HOSTS << mod
      end
      
    end
    
    # The path where the plugins can be found.
    def plugin_path *args
      unless args.empty?
        @plugin_path = File.expand_path File.join(*args)
      end
      @plugin_path ||= ''
    end
    
    # Map a plugin_id to another.
    #
    # Usage: Put this in a file plugin_path/_map.rb.
    #
    #  class MyColorHost < PluginHost
    #    map :navy => :dark_blue,
    #      :maroon => :brown,
    #      :luna => :moon
    #  end
    def map hash
      for from, to in hash
        from = validate_id from
        to = validate_id to
        plugin_hash[from] = to unless plugin_hash.has_key? from
      end
    end
    
    # Define the default plugin to use when no plugin is found
    # for a given id, or return the default plugin.
    #
    # See also map.
    #
    #  class MyColorHost < PluginHost
    #    map :navy => :dark_blue
    #    default :gray
    #  end
    #  
    #  MyColorHost.default  # loads and returns the Gray plugin
    def default id = nil
      if id
        id = validate_id id
        raise "The default plugin can't be named \"default\"." if id == :default
        plugin_hash[:default] = id
      else
        load :default
      end
    end
    
    # Every plugin must register itself for +id+ by calling register_for,
    # which calls this method.
    #
    # See Plugin#register_for.
    def register plugin, id
      plugin_hash[validate_id(id)] = plugin
    end
    
    # A Hash of plugion_id => Plugin pairs.
    def plugin_hash
      @plugin_hash ||= make_plugin_hash
    end
    
    # Returns an array of all .rb files in the plugin path.
    #
    # The extension .rb is not included.
    def list
      Dir[path_to('*')].select do |file|
        File.basename(file)[/^(?!_)\w+\.rb$/]
      end.map do |file|
        File.basename(file, '.rb').to_sym
      end
    end
    
    # Returns an array of all Plugins.
    # 
    # Note: This loads all plugins using load_all.
    def all_plugins
      load_all
      plugin_hash.values.grep(Class)
    end
    
    # Loads the map file (see map).
    #
    # This is done automatically when plugin_path is called.
    def load_plugin_map
      mapfile = path_to '_map'
      @plugin_map_loaded = true
      if File.exist? mapfile
        require mapfile
        true
      else
        false
      end
    end
    
  protected
    
    # Return a plugin hash that automatically loads plugins.
    def make_plugin_hash
      @plugin_map_loaded ||= false
      Hash.new do |h, plugin_id|
        id = validate_id(plugin_id)
        path = path_to id
        begin
          raise LoadError, "#{path} not found" unless File.exist? path
          require path
        rescue LoadError => boom
          if @plugin_map_loaded
            if h.has_key?(:default)
              warn '%p could not load plugin %p; falling back to %p' % [self, id, h[:default]]
              h[:default]
            else
              raise PluginNotFound, '%p could not load plugin %p: %s' % [self, id, boom]
            end
          else
            load_plugin_map
            h[plugin_id]
          end
        else
          # Plugin should have registered by now
          if h.has_key? id
            h[id]
          else
            raise PluginNotFound, "No #{self.name} plugin for #{id.inspect} found in #{path}."
          end
        end
      end
    end
    
    # Returns the expected path to the plugin file for the given id.
    def path_to plugin_id
      File.join plugin_path, "#{plugin_id}.rb"
    end
    
    # Converts +id+ to a Symbol if it is a String,
    # or returns +id+ if it already is a Symbol.
    #
    # Raises +ArgumentError+ for all other objects, or if the
    # given String includes non-alphanumeric characters (\W).
    def validate_id id
      if id.is_a? Symbol or id.nil?
        id
      elsif id.is_a? String
        if id[/\w+/] == id
          id.downcase.to_sym
        else
          raise ArgumentError, "Invalid id given: #{id}"
        end
      else
        raise ArgumentError, "String or Symbol expected, but #{id.class} given."
      end
    end
    
  end
  
  
  # = Plugin
  #
  #  Plugins have to include this module.
  #
  #  IMPORTANT: Use extend for this module.
  #
  #  See CodeRay::PluginHost for examples.
  module Plugin
    
    attr_reader :plugin_id
    
    # Register this class for the given +id+.
    # 
    # Example:
    #   class MyPlugin < PluginHost::BaseClass
    #     register_for :my_id
    #     ...
    #   end
    #
    # See PluginHost.register.
    def register_for id
      @plugin_id = id
      plugin_host.register self, id
    end
    
    # Returns the title of the plugin, or sets it to the
    # optional argument +title+.
    def title title = nil
      if title
        @title = title.to_s
      else
        @title ||= name[/([^:]+)$/, 1]
      end
    end
    
    # The PluginHost for this Plugin class.
    def plugin_host host = nil
      if host.is_a? PluginHost
        const_set :PLUGIN_HOST, host
      end
      self::PLUGIN_HOST
    end
    
    def aliases
      plugin_host.load_plugin_map
      plugin_host.plugin_hash.inject [] do |aliases, (key, _)|
        aliases << key if plugin_host[key] == self
        aliases
      end
    end
    
  end
  
end