Adds engines 2.1.0 plugin.

git-svn-id: http://redmine.rubyforge.org/svn/trunk@1654 e93f8b46-1217-0410-a6f0-8f06a7374b81

vendor/plugins/engines/lib/engines.rb

@@ -0,0 +1,174 @@
+require 'active_support'
+require File.join(File.dirname(__FILE__), 'engines/plugin')
+require File.join(File.dirname(__FILE__), 'engines/plugin/list')
+require File.join(File.dirname(__FILE__), 'engines/plugin/loader')
+require File.join(File.dirname(__FILE__), 'engines/plugin/locator')
+require File.join(File.dirname(__FILE__), 'engines/assets')
+require File.join(File.dirname(__FILE__), 'engines/rails_extensions/rails')
+
+# == Parameters
+#
+# The Engines module has a number of public configuration parameters:
+#
+# [+public_directory+]  The directory into which plugin assets should be
+#                       mirrored. Defaults to <tt>RAILS_ROOT/public/plugin_assets</tt>.
+# [+schema_info_table+] The table to use when storing plugin migration 
+#                       version information. Defaults to +plugin_schema_info+.
+#
+# Additionally, there are a few flags which control the behaviour of
+# some of the features the engines plugin adds to Rails:
+#
+# [+disable_application_view_loading+] A boolean flag determining whether
+#                                      or not views should be loaded from 
+#                                      the main <tt>app/views</tt> directory.
+#                                      Defaults to false; probably only 
+#                                      useful when testing your plugin.
+# [+disable_application_code_loading+] A boolean flag determining whether
+#                                      or not to load controllers/helpers 
+#                                      from the main +app+ directory,
+#                                      if corresponding code exists within 
+#                                      a plugin. Defaults to false; again, 
+#                                      probably only useful when testing 
+#                                      your plugin.
+# [+disable_code_mixing+] A boolean flag indicating whether all plugin
+#                         copies of a particular controller/helper should 
+#                         be loaded and allowed to override each other, 
+#                         or if the first matching file should be loaded 
+#                         instead. Defaults to false.
+#
+module Engines
+  # The set of all loaded plugins
+  mattr_accessor :plugins
+  self.plugins = Engines::Plugin::List.new  
+  
+  # List of extensions to load, can be changed in init.rb before calling Engines.init
+  mattr_accessor :rails_extensions
+  self.rails_extensions = %w(action_mailer asset_helpers routing migrations dependencies)
+  
+  # The name of the public directory to mirror public engine assets into.
+  # Defaults to <tt>RAILS_ROOT/public/plugin_assets</tt>.
+  mattr_accessor :public_directory
+  self.public_directory = File.join(RAILS_ROOT, 'public', 'plugin_assets')
+
+  # The table in which to store plugin schema information. Defaults to
+  # "plugin_schema_info".
+  mattr_accessor :schema_info_table
+  self.schema_info_table = "plugin_schema_info"
+
+  #--
+  # These attributes control the behaviour of the engines extensions
+  #++
+  
+  # Set this to true if views should *only* be loaded from plugins
+  mattr_accessor :disable_application_view_loading
+  self.disable_application_view_loading = false
+  
+  # Set this to true if controller/helper code shouldn't be loaded 
+  # from the application
+  mattr_accessor :disable_application_code_loading
+  self.disable_application_code_loading = false
+  
+  # Set this ti true if code should not be mixed (i.e. it will be loaded
+  # from the first valid path on $LOAD_PATH)
+  mattr_accessor :disable_code_mixing
+  self.disable_code_mixing = false
+  
+  # This is used to determine which files are candidates for the "code
+  # mixing" feature that the engines plugin provides, where classes from
+  # plugins can be loaded, and then code from the application loaded
+  # on top of that code to override certain methods.
+  mattr_accessor :code_mixing_file_types
+  self.code_mixing_file_types = %w(controller helper)
+  
+  class << self
+    def init
+      load_extensions
+      Engines::Assets.initialize_base_public_directory
+    end
+    
+    def logger
+      RAILS_DEFAULT_LOGGER
+    end
+    
+    def load_extensions
+      rails_extensions.each { |name| require "engines/rails_extensions/#{name}" }
+      # load the testing extensions, if we are in the test environment.
+      require "engines/testing" if RAILS_ENV == "test"
+    end
+    
+    def select_existing_paths(paths)
+      paths.select { |path| File.directory?(path) }
+    end  
+  
+    # The engines plugin will, by default, mix code from controllers and helpers,
+    # allowing application code to override specific methods in the corresponding
+    # controller or helper classes and modules. However, if other file types should
+    # also be mixed like this, they can be added by calling this method. For example,
+    # if you want to include "things" within your plugin and override them from
+    # your applications, you should use the following layout:
+    #
+    #   app/
+    #    +-- things/
+    #    |       +-- one_thing.rb
+    #    |       +-- another_thing.rb
+    #   ...
+    #   vendor/
+    #       +-- plugins/
+    #                +-- my_plugin/
+    #                           +-- app/
+    #                                +-- things/
+    #                                        +-- one_thing.rb
+    #                                        +-- another_thing.rb
+    #
+    # The important point here is that your "things" are named <whatever>_thing.rb,
+    # and that they are placed within plugin/app/things (the pluralized form of 'thing').
+    # 
+    # It's important to note that you'll also want to ensure that the "things" are
+    # on your load path in your plugin's init.rb:
+    #
+    #   Rails.plugins[:my_plugin].code_paths << "app/things"
+    #
+    def mix_code_from(*types)
+      self.code_mixing_file_types += types.map { |x| x.to_s.singularize }
+    end
+    
+    # A general purpose method to mirror a directory (+source+) into a destination
+    # directory, including all files and subdirectories. Files will not be mirrored
+    # if they are identical already (checked via FileUtils#identical?).
+    def mirror_files_from(source, destination)
+      return unless File.directory?(source)
+      
+      # TODO: use Rake::FileList#pathmap?    
+      source_files = Dir[source + "/**/*"]
+      source_dirs = source_files.select { |d| File.directory?(d) }
+      source_files -= source_dirs
+      
+      unless source_files.empty?
+        base_target_dir = File.join(destination, File.dirname(source_files.first))
+        FileUtils.mkdir_p(base_target_dir)
+      end
+      
+      source_dirs.each do |dir|
+        # strip down these paths so we have simple, relative paths we can
+        # add to the destination
+        target_dir = File.join(destination, dir.gsub(source, ''))
+        begin        
+          FileUtils.mkdir_p(target_dir)
+        rescue Exception => e
+          raise "Could not create directory #{target_dir}: \n" + e
+        end
+      end
+      
+      source_files.each do |file|
+        begin
+          target = File.join(destination, file.gsub(source, ''))
+          unless File.exist?(target) && FileUtils.identical?(file, target)
+            FileUtils.cp(file, target)
+          end 
+        rescue Exception => e
+          raise "Could not copy #{file} to #{target}: \n" + e 
+        end
+      end  
+    end   
+  end  
+end