middleman/middleman-core/lib/middleman-core/callback_manager.rb

55 lines
1.7 KiB
Ruby

require 'hamster'
require 'middleman-core/contracts'
# Immutable Callback Management, complete with Contracts validation.
module Middleman
class CallbackManager
include Contracts
Contract Any
def initialize
@callbacks = ::Hamster.hash
end
Contract RespondTo[:define_singleton_method], ArrayOf[Symbol], Maybe[Proc] => Any
def install_methods!(install_target, names, &block)
manager = self
names.each do |name|
method_name = block_given? ? block.call(name) : name
install_target.define_singleton_method(method_name) do |*keys, &b|
key_set = keys.unshift(name)
manager.add(key_set.length > 1 ? key_set : key_set.first, &b)
end
end
install_target.define_singleton_method(:execute_callbacks) do |keys, *args|
manager.execute(keys, args[0], self)
end
install_target.define_singleton_method(:callbacks_for, &method(:callbacks_for))
end
Contract Or[Symbol, ArrayOf[Symbol]], Proc => Any
def add(keys, &block)
immutable_keys = keys.is_a?(Symbol) ? keys : ::Hamster::Vector.new(keys)
@callbacks = @callbacks.put(immutable_keys) do |v|
v.nil? ? ::Hamster.set(block) : v.add(block)
end
end
Contract Or[Symbol, ArrayOf[Symbol]], Maybe[ArrayOf[Any]], Maybe[RespondTo[:instance_exec]] => Any
def execute(keys, args=[], scope=self)
callbacks_for(keys).each { |b| scope.instance_exec(*args, &b) }
end
Contract Or[Symbol, ArrayOf[Symbol]] => ::Hamster::Set
def callbacks_for(keys)
immutable_keys = keys.is_a?(Symbol) ? keys : ::Hamster::Vector.new(keys)
@callbacks.get(immutable_keys) || ::Hamster.set
end
end
end