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rails--rails/railties/lib/rails/plugin/locator.rb
2009-05-16 12:28:25 -07:00

100 lines
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3.7 KiB
Ruby

module Rails
class Plugin
# The Plugin::Locator class should be subclasses to provide custom plugin-finding
# abilities to Rails (i.e. loading plugins from Gems, etc). Each subclass should implement
# the <tt>located_plugins</tt> method, which return an array of Plugin objects that have been found.
class Locator
include Enumerable
attr_reader :initializer
def initialize(initializer)
@initializer = initializer
end
# This method should return all the plugins which this Plugin::Locator can find
# These will then be used by the current Plugin::Loader, which is responsible for actually
# loading the plugins themselves
def plugins
raise "The `plugins' method must be defined by concrete subclasses of #{self.class}"
end
def each(&block)
plugins.each(&block)
end
def plugin_names
plugins.map {|plugin| plugin.name }
end
end
# The Rails::Plugin::FileSystemLocator will try to locate plugins by examining the directories
# in the paths given in configuration.plugin_paths. Any plugins that can be found are returned
# in a list.
#
# The criteria for a valid plugin in this case is found in Rails::Plugin#valid?, although
# other subclasses of Rails::Plugin::Locator can of course use different conditions.
class FileSystemLocator < Locator
# Returns all the plugins which can be loaded in the filesystem, under the paths given
# by configuration.plugin_paths.
def plugins
initializer.configuration.plugin_paths.flatten.inject([]) do |plugins, path|
plugins.concat locate_plugins_under(path)
plugins
end.flatten
end
private
# Attempts to create a plugin from the given path. If the created plugin is valid?
# (see Rails::Plugin#valid?) then the plugin instance is returned; otherwise nil.
def create_plugin(path)
plugin = Rails::Plugin.new(path)
plugin.valid? ? plugin : nil
end
# This starts at the base path looking for valid plugins (see Rails::Plugin#valid?).
# Since plugins can be nested arbitrarily deep within an unspecified number of intermediary
# directories, this method runs recursively until it finds a plugin directory, e.g.
#
# locate_plugins_under('vendor/plugins/acts/acts_as_chunky_bacon')
# => <Rails::Plugin name: 'acts_as_chunky_bacon' ... >
#
def locate_plugins_under(base_path)
Dir.glob(File.join(base_path, '*')).sort.inject([]) do |plugins, path|
if plugin = create_plugin(path)
plugins << plugin
elsif File.directory?(path)
plugins.concat locate_plugins_under(path)
end
plugins
end
end
end
# The GemLocator scans all the loaded RubyGems, looking for gems with
# a <tt>rails/init.rb</tt> file.
class GemLocator < Locator
def plugins
gem_index = initializer.configuration.gems.inject({}) { |memo, gem| memo.update gem.specification => gem }
specs = gem_index.keys
specs += Gem.loaded_specs.values.select do |spec|
spec.loaded_from && # prune stubs
File.exist?(File.join(spec.full_gem_path, "rails", "init.rb"))
end
specs.compact!
require "rubygems/dependency_list"
deps = Gem::DependencyList.new
deps.add(*specs) unless specs.empty?
deps.dependency_order.collect do |spec|
Rails::GemPlugin.new(spec, gem_index[spec])
end
end
end
end
end