From 21e7b8462113fc7c0fd1882dcc2bf7225de67b1a Mon Sep 17 00:00:00 2001 From: Joshua Peek Date: Mon, 12 Oct 2009 22:15:43 -0500 Subject: Callbacks, DeprecatedCallbacks = NewCallbacks, Callbacks --- activesupport/lib/active_support/callbacks.rb | 622 +++++++++++++++++++------- 1 file changed, 452 insertions(+), 170 deletions(-) (limited to 'activesupport/lib/active_support/callbacks.rb') diff --git a/activesupport/lib/active_support/callbacks.rb b/activesupport/lib/active_support/callbacks.rb index 238d1b6804..21388d7a58 100644 --- a/activesupport/lib/active_support/callbacks.rb +++ b/activesupport/lib/active_support/callbacks.rb @@ -1,4 +1,6 @@ -require 'active_support/core_ext/array/extract_options' +require 'active_support/core_ext/array/wrap' +require 'active_support/core_ext/class/inheritable_attributes' +require 'active_support/core_ext/kernel/reporting' module ActiveSupport # Callbacks are hooks into the lifecycle of an object that allow you to trigger logic @@ -10,23 +12,23 @@ module ActiveSupport # class Storage # include ActiveSupport::Callbacks # - # define_callbacks :before_save, :after_save + # define_callbacks :save # end # # class ConfigStorage < Storage - # before_save :saving_message + # set_callback :save, :before, :saving_message # def saving_message # puts "saving..." # end # - # after_save do |object| + # set_callback :save, :after do |object| # puts "saved" # end # # def save - # run_callbacks(:before_save) - # puts "- save" - # run_callbacks(:after_save) + # run_callbacks :save do + # puts "- save" + # end # end # end # @@ -44,28 +46,28 @@ module ActiveSupport # class Storage # include ActiveSupport::Callbacks # - # define_callbacks :before_save, :after_save + # define_callbacks :save # - # before_save :prepare + # set_callback :save, :before, :prepare # def prepare # puts "preparing save" # end # end # # class ConfigStorage < Storage - # before_save :saving_message + # set_callback :save, :before, :saving_message # def saving_message # puts "saving..." # end # - # after_save do |object| + # set_callback :save, :after do |object| # puts "saved" # end # # def save - # run_callbacks(:before_save) - # puts "- save" - # run_callbacks(:after_save) + # run_callbacks :save do + # puts "- save" + # end # end # end # @@ -77,205 +79,485 @@ module ActiveSupport # saving... # - save # saved + # module Callbacks - class CallbackChain < Array - def self.build(kind, *methods, &block) - methods, options = extract_options(*methods, &block) - methods.map! { |method| Callback.new(kind, method, options) } - new(methods) + def self.included(klass) + klass.extend ClassMethods + end + + def run_callbacks(kind, *args, &block) + send("_run_#{kind}_callbacks", *args, &block) + end + + class Callback + @@_callback_sequence = 0 + + attr_accessor :chain, :filter, :kind, :options, :per_key, :klass + + def initialize(chain, filter, kind, options, klass) + @chain, @kind, @klass = chain, kind, klass + normalize_options!(options) + + @per_key = options.delete(:per_key) + @raw_filter, @options = filter, options + @filter = _compile_filter(filter) + @compiled_options = _compile_options(options) + @callback_id = next_id + + _compile_per_key_options + end + + def clone(chain, klass) + obj = super() + obj.chain = chain + obj.klass = klass + obj.per_key = @per_key.dup + obj.options = @options.dup + obj.per_key[:if] = @per_key[:if].dup + obj.per_key[:unless] = @per_key[:unless].dup + obj.options[:if] = @options[:if].dup + obj.options[:unless] = @options[:unless].dup + obj end - def run(object, options = {}, &terminator) - enumerator = options[:enumerator] || :each + def normalize_options!(options) + options[:if] = Array.wrap(options[:if]) + options[:unless] = Array.wrap(options[:unless]) - unless block_given? - send(enumerator) { |callback| callback.call(object) } - else - send(enumerator) do |callback| - result = callback.call(object) - break result if terminator.call(result, object) + options[:per_key] ||= {} + options[:per_key][:if] = Array.wrap(options[:per_key][:if]) + options[:per_key][:unless] = Array.wrap(options[:per_key][:unless]) + end + + def name + chain.name + end + + def next_id + @@_callback_sequence += 1 + end + + def matches?(_kind, _filter) + @kind == _kind && @filter == _filter + end + + def _update_filter(filter_options, new_options) + filter_options[:if].push(new_options[:unless]) if new_options.key?(:unless) + filter_options[:unless].push(new_options[:if]) if new_options.key?(:if) + end + + def recompile!(_options, _per_key) + _update_filter(self.options, _options) + _update_filter(self.per_key, _per_key) + + @callback_id = next_id + @filter = _compile_filter(@raw_filter) + @compiled_options = _compile_options(@options) + _compile_per_key_options + end + + def _compile_per_key_options + key_options = _compile_options(@per_key) + + @klass.class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1 + def _one_time_conditions_valid_#{@callback_id}? + true #{key_options[0]} end - end + RUBY_EVAL end - # TODO: Decompose into more Array like behavior - def replace_or_append!(chain) - if index = index(chain) - self[index] = chain - else - self << chain + # This will supply contents for before and around filters, and no + # contents for after filters (for the forward pass). + def start(key=nil, object=nil) + return if key && !object.send("_one_time_conditions_valid_#{@callback_id}?") + + # options[0] is the compiled form of supplied conditions + # options[1] is the "end" for the conditional + # + if @kind == :before || @kind == :around + if @kind == :before + # if condition # before_save :filter_name, :if => :condition + # filter_name + # end + filter = <<-RUBY_EVAL + unless halted + result = #{@filter} + halted = (#{chain.config[:terminator]}) + end + RUBY_EVAL + + [@compiled_options[0], filter, @compiled_options[1]].compact.join("\n") + else + # Compile around filters with conditions into proxy methods + # that contain the conditions. + # + # For `around_save :filter_name, :if => :condition': + # + # def _conditional_callback_save_17 + # if condition + # filter_name do + # yield self + # end + # else + # yield self + # end + # end + # + name = "_conditional_callback_#{@kind}_#{next_id}" + txt, line = <<-RUBY_EVAL, __LINE__ + 1 + def #{name}(halted) + #{@compiled_options[0] || "if true"} && !halted + #{@filter} do + yield self + end + else + yield self + end + end + RUBY_EVAL + @klass.class_eval(txt, __FILE__, line) + "#{name}(halted) do" + end end - self end - def find(callback, &block) - select { |c| c == callback && (!block_given? || yield(c)) }.first - end + # This will supply contents for around and after filters, but not + # before filters (for the backward pass). + def end(key=nil, object=nil) + return if key && !object.send("_one_time_conditions_valid_#{@callback_id}?") - def delete(callback) - super(callback.is_a?(Callback) ? callback : find(callback)) + if @kind == :around || @kind == :after + # if condition # after_save :filter_name, :if => :condition + # filter_name + # end + if @kind == :after + [@compiled_options[0], @filter, @compiled_options[1]].compact.join("\n") + else + "end" + end + end end private - def self.extract_options(*methods, &block) - methods.flatten! - options = methods.extract_options! - methods << block if block_given? - return methods, options - end - def extract_options(*methods, &block) - self.class.extract_options(*methods, &block) + # Options support the same options as filters themselves (and support + # symbols, string, procs, and objects), so compile a conditional + # expression based on the options + def _compile_options(options) + return [] if options[:if].empty? && options[:unless].empty? + + conditions = [] + + unless options[:if].empty? + conditions << Array.wrap(_compile_filter(options[:if])) end - end - class Callback - attr_reader :kind, :method, :identifier, :options + unless options[:unless].empty? + conditions << Array.wrap(_compile_filter(options[:unless])).map {|f| "!#{f}"} + end - def initialize(kind, method, options = {}) - @kind = kind - @method = method - @identifier = options[:identifier] - @options = options + ["if #{conditions.flatten.join(" && ")}", "end"] end - def ==(other) - case other - when Callback - (self.identifier && self.identifier == other.identifier) || self.method == other.method + # Filters support: + # + # Arrays:: Used in conditions. This is used to specify + # multiple conditions. Used internally to + # merge conditions from skip_* filters + # Symbols:: A method to call + # Strings:: Some content to evaluate + # Procs:: A proc to call with the object + # Objects:: An object with a before_foo method on it to call + # + # All of these objects are compiled into methods and handled + # the same after this point: + # + # Arrays:: Merged together into a single filter + # Symbols:: Already methods + # Strings:: class_eval'ed into methods + # Procs:: define_method'ed into methods + # Objects:: + # a method is created that calls the before_foo method + # on the object. + # + def _compile_filter(filter) + method_name = "_callback_#{@kind}_#{next_id}" + case filter + when Array + filter.map {|f| _compile_filter(f)} + when Symbol + filter + when String + "(#{filter})" + when Proc + @klass.send(:define_method, method_name, &filter) + return method_name if filter.arity <= 0 + + method_name << (filter.arity == 1 ? "(self)" : " self, Proc.new ") else - (self.identifier && self.identifier == other) || self.method == other + @klass.send(:define_method, "#{method_name}_object") { filter } + + _normalize_legacy_filter(kind, filter) + scopes = Array.wrap(chain.config[:scope]) + method_to_call = scopes.map{ |s| s.is_a?(Symbol) ? send(s) : s }.join("_") + + @klass.class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1 + def #{method_name}(&blk) + #{method_name}_object.send(:#{method_to_call}, self, &blk) + end + RUBY_EVAL + + method_name end end - def eql?(other) - self == other + def _normalize_legacy_filter(kind, filter) + if !filter.respond_to?(kind) && filter.respond_to?(:filter) + filter.metaclass.class_eval( + "def #{kind}(context, &block) filter(context, &block) end", + __FILE__, __LINE__ - 1) + elsif filter.respond_to?(:before) && filter.respond_to?(:after) && kind == :around + def filter.around(context) + should_continue = before(context) + yield if should_continue + after(context) + end + end end + end - def dup - self.class.new(@kind, @method, @options.dup) + # An Array with a compile method + class CallbackChain < Array + attr_reader :name, :config + + def initialize(name, config) + @name = name + @config = { + :terminator => "false", + :rescuable => false, + :scope => [ :kind ] + }.merge(config) end - def hash - if @identifier - @identifier.hash - else - @method.hash + def compile(key=nil, object=nil) + method = [] + method << "value = nil" + method << "halted = false" + + each do |callback| + method << callback.start(key, object) + end + + if config[:rescuable] + method << "rescued_error = nil" + method << "begin" + end + + method << "value = yield if block_given? && !halted" + + if config[:rescuable] + method << "rescue Exception => e" + method << "rescued_error = e" + method << "end" end + + reverse_each do |callback| + method << callback.end(key, object) + end + + method << "raise rescued_error if rescued_error" if config[:rescuable] + method << "halted ? false : (block_given? ? value : true)" + method.compact.join("\n") end - def call(*args, &block) - evaluate_method(method, *args, &block) if should_run_callback?(*args) - rescue LocalJumpError - raise ArgumentError, - "Cannot yield from a Proc type filter. The Proc must take two " + - "arguments and execute #call on the second argument." + def clone(klass) + chain = CallbackChain.new(@name, @config.dup) + callbacks = map { |c| c.clone(chain, klass) } + chain.push(*callbacks) end + end - private - def evaluate_method(method, *args, &block) - case method - when Symbol - object = args.shift - object.send(method, *args, &block) - when String - eval(method, args.first.instance_eval { binding }) - when Proc, Method - method.call(*args, &block) - else - if method.respond_to?(kind) - method.send(kind, *args, &block) - else - raise ArgumentError, - "Callbacks must be a symbol denoting the method to call, a string to be evaluated, " + - "a block to be invoked, or an object responding to the callback method." + module ClassMethods + # Make the run_callbacks :save method. The generated method takes + # a block that it'll yield to. It'll call the before and around filters + # in order, yield the block, and then run the after filters. + # + # run_callbacks :save do + # save + # end + # + # The run_callbacks :save method can optionally take a key, which + # will be used to compile an optimized callback method for each + # key. See #define_callbacks for more information. + # + def __define_runner(symbol) #:nodoc: + body = send("_#{symbol}_callbacks").compile(nil) + + body, line = <<-RUBY_EVAL, __LINE__ + def _run_#{symbol}_callbacks(key = nil, &blk) + if key + name = "_run__\#{self.class.name.hash.abs}__#{symbol}__\#{key.hash.abs}__callbacks" + + unless respond_to?(name) + self.class.__create_keyed_callback(name, :#{symbol}, self, &blk) end + + send(name, &blk) + else + #{body} + end end + private :_run_#{symbol}_callbacks + RUBY_EVAL + + silence_warnings do + undef_method "_run_#{symbol}_callbacks" if method_defined?("_run_#{symbol}_callbacks") + class_eval body, __FILE__, line end + end - def should_run_callback?(*args) - [options[:if]].flatten.compact.all? { |a| evaluate_method(a, *args) } && - ![options[:unless]].flatten.compact.any? { |a| evaluate_method(a, *args) } + # This is called the first time a callback is called with a particular + # key. It creates a new callback method for the key, calculating + # which callbacks can be omitted because of per_key conditions. + # + def __create_keyed_callback(name, kind, object, &blk) #:nodoc: + @_keyed_callbacks ||= {} + @_keyed_callbacks[name] ||= begin + str = send("_#{kind}_callbacks").compile(name, object) + class_eval "def #{name}() #{str} end", __FILE__, __LINE__ + true end - end + end - def self.included(base) - base.extend ClassMethods - end + # This is used internally to append, prepend and skip callbacks to the + # CallbackChain. + # + def __update_callbacks(name, filters = [], block = nil) #:nodoc: + type = [:before, :after, :around].include?(filters.first) ? filters.shift : :before + options = filters.last.is_a?(Hash) ? filters.pop : {} + filters.unshift(block) if block - module ClassMethods - def define_callbacks(*callbacks) - callbacks.each do |callback| - class_eval <<-"end_eval", __FILE__, __LINE__ + 1 - def self.#{callback}(*methods, &block) # def self.before_save(*methods, &block) - callbacks = CallbackChain.build(:#{callback}, *methods, &block) # callbacks = CallbackChain.build(:before_save, *methods, &block) - @#{callback}_callbacks ||= CallbackChain.new # @before_save_callbacks ||= CallbackChain.new - @#{callback}_callbacks.concat callbacks # @before_save_callbacks.concat callbacks - end # end - # - def self.#{callback}_callback_chain # def self.before_save_callback_chain - @#{callback}_callbacks ||= CallbackChain.new # @before_save_callbacks ||= CallbackChain.new - # - if superclass.respond_to?(:#{callback}_callback_chain) # if superclass.respond_to?(:before_save_callback_chain) - CallbackChain.new( # CallbackChain.new( - superclass.#{callback}_callback_chain + # superclass.before_save_callback_chain + - @#{callback}_callbacks # @before_save_callbacks - ) # ) - else # else - @#{callback}_callbacks # @before_save_callbacks - end # end - end # end - end_eval + chain = send("_#{name}_callbacks") + yield chain, type, filters, options if block_given? + + __define_runner(name) + end + + # Set callbacks for a previously defined callback. + # + # Syntax: + # set_callback :save, :before, :before_meth + # set_callback :save, :after, :after_meth, :if => :condition + # set_callback :save, :around, lambda { |r| stuff; yield; stuff } + # + # Use skip_callback to skip any defined one. + # + # When creating or skipping callbacks, you can specify conditions that + # are always the same for a given key. For instance, in ActionPack, + # we convert :only and :except conditions into per-key conditions. + # + # before_filter :authenticate, :except => "index" + # becomes + # dispatch_callback :before, :authenticate, :per_key => {:unless => proc {|c| c.action_name == "index"}} + # + # Per-Key conditions are evaluated only once per use of a given key. + # In the case of the above example, you would do: + # + # run_callbacks(:dispatch, action_name) { ... dispatch stuff ... } + # + # In that case, each action_name would get its own compiled callback + # method that took into consideration the per_key conditions. This + # is a speed improvement for ActionPack. + # + def set_callback(name, *filters, &block) + __update_callbacks(name, filters, block) do |chain, type, filters, options| + filters.map! do |filter| + chain.delete_if {|c| c.matches?(type, filter) } + Callback.new(chain, filter, type, options.dup, self) + end + + options[:prepend] ? chain.unshift(*filters) : chain.push(*filters) end end - end - # Runs all the callbacks defined for the given options. - # - # If a block is given it will be called after each callback receiving as arguments: - # - # * the result from the callback - # * the object which has the callback - # - # If the result from the block evaluates to +true+, the callback chain is stopped. - # - # Example: - # class Storage - # include ActiveSupport::Callbacks - # - # define_callbacks :before_save, :after_save - # end - # - # class ConfigStorage < Storage - # before_save :pass - # before_save :pass - # before_save :stop - # before_save :pass - # - # def pass - # puts "pass" - # end - # - # def stop - # puts "stop" - # return false - # end - # - # def save - # result = run_callbacks(:before_save) { |result, object| result == false } - # puts "- save" if result - # end - # end - # - # config = ConfigStorage.new - # config.save - # - # Output: - # pass - # pass - # stop - def run_callbacks(kind, options = {}, &block) - self.class.send("#{kind}_callback_chain").run(self, options, &block) + # Skip a previously defined callback for a given type. + # + def skip_callback(name, *filters, &block) + __update_callbacks(name, filters, block) do |chain, type, filters, options| + chain = send("_#{name}_callbacks=", chain.clone(self)) + + filters.each do |filter| + filter = chain.find {|c| c.matches?(type, filter) } + + if filter && options.any? + filter.recompile!(options, options[:per_key] || {}) + else + chain.delete(filter) + end + end + end + end + + # Reset callbacks for a given type. + # + def reset_callbacks(symbol) + send("_#{symbol}_callbacks").clear + __define_runner(symbol) + end + + # Define callbacks types. + # + # ==== Example + # + # define_callbacks :validate + # + # ==== Options + # + # * :terminator - Indicates when a before filter is considered + # to be halted. + # + # define_callbacks :validate, :terminator => "result == false" + # + # In the example above, if any before validate callbacks returns false, + # other callbacks are not executed. Defaults to "false". + # + # * :rescuable - By default, after filters are not executed if + # the given block or an before_filter raises an error. Supply :rescuable => true + # to change this behavior. + # + # * :scope - Show which methods should be executed when a class + # is giben as callback: + # + # define_callbacks :filters, :scope => [ :kind ] + # + # When a class is given: + # + # before_filter MyFilter + # + # It will call the type of the filter in the given class, which in this + # case, is "before". + # + # If, for instance, you supply the given scope: + # + # define_callbacks :validate, :scope => [ :kind, :name ] + # + # It will call "#{kind}_#{name}" in the given class. So "before_validate" + # will be called in the class below: + # + # before_validate MyValidation + # + # Defaults to :kind. + # + def define_callbacks(*symbols) + config = symbols.last.is_a?(Hash) ? symbols.pop : {} + symbols.each do |symbol| + extlib_inheritable_accessor("_#{symbol}_callbacks") do + CallbackChain.new(symbol, config) + end + + __define_runner(symbol) + end + end end end end -- cgit v1.2.3