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

104 lines
2.8 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, or return it from the block:
#
# @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 a matching extension that passed the
# version check, bail out.
return if registered.has_key?(name.to_sym) &&
!registered[name.to_sym].is_a?(String)
registered[name.to_sym] = if block_given?
block
elsif namespace
namespace
end
end
def load(name)
name = name.to_sym
return nil unless registered.has_key?(name)
extension = registered[name]
if extension.is_a?(Proc)
extension = extension.call() || nil
registered[name] = extension
end
extension
end
end
end
# Where to look in gems for extensions to auto-register
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"
begin
require "middleman-more"
rescue LoadError
end
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
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