middleman/middleman-core/lib/middleman-core/extensions.rb

125 lines
3.8 KiB
Ruby

module Middleman
module Extensions
class << self
def registered
@_registered ||= {}
end
# Register a new extension. Choose a name which will be
# used to activate the extension in config.rb, like this:
#
# activate :my_extension
#
# Provide your extension module either as the namespace
# parameter:
#
# Middleman::Extensions.register(:my_extension, MyExtension)
#
# Or return it from a block:
#
# Middleman::Extensions.register(:my_extension) do
# require 'my_extension'
# MyExtension
# end
#
# @param [Symbol] name The name of the extension
# @param [Module] namespace The extension module
# @yield Instead of passing a module in namespace, you can provide
# a block which returns your extension module. This gives
# you the ability to require other files only when the
# extension is activated.
def register(name, namespace=nil, &block)
# If we've already got an extension registered under this name, bail out
if registered.has_key?(name.to_sym)
raise "There is already an extension registered with the name '#{name}'"
end
registered[name.to_sym] = if block_given?
block
elsif namespace && namespace.ancestors.include?(::Middleman::Extension)
namespace
else
raise "You must provide a Middleman::Extension or a block that returns a Middleman::Extension"
end
end
# Load an extension by name, evaluating block definition if necessary.
def load(name)
name = name.to_sym
unless registered.has_key?(name)
raise "Unknown Extension: #{name}. Check the name and make sure you have referenced the extension's gem in your Gemfile."
end
extension = registered[name]
if extension.is_a?(Proc)
extension = extension.call()
registered[name] = extension
end
if !extension.ancestors.include?(::Middleman::Extension)
raise "Tried to activate old-style extension: #{name}. They are no longer supported."
end
# Set the extension's name to whatever it was registered as.
extension.ext_name = name
extension
end
end
end
# Where to look in gems for extensions to auto-register. Since most extensions are
# called out in a Gemfile, this is really only useful for template extensions that get
# used by "middleman init".
EXTENSION_FILE = File.join('lib', 'middleman_extension.rb') unless const_defined?(:EXTENSION_FILE)
class << self
# Automatically load extensions from available RubyGems
# which contain the EXTENSION_FILE
#
# @private
def load_extensions_in_path
require 'rubygems'
extensions = rubygems_latest_specs.select do |spec|
spec_has_file?(spec, EXTENSION_FILE)
end
extensions.each do |spec|
require spec.name
end
end
# Backwards compatible means of finding all the latest gemspecs
# available on the system
#
# @private
# @return [Array] Array of latest Gem::Specification
def rubygems_latest_specs
# If newer Rubygems
if ::Gem::Specification.respond_to? :latest_specs
::Gem::Specification.latest_specs(true)
else
::Gem.source_index.latest_specs
end
end
# Where a given Gem::Specification has a specific file. Used
# to discover extensions.
#
# @private
# @param [Gem::Specification] spec
# @param [String] path Path to look for
# @return [Boolean] Whether the file exists
def spec_has_file?(spec, path)
full_path = File.join(spec.full_gem_path, path)
File.exists?(full_path)
end
end
end
require 'middleman-core/extension'