diff options
Diffstat (limited to 'activesupport/lib/active_support/callbacks.rb')
| -rw-r--r-- | activesupport/lib/active_support/callbacks.rb | 330 |
1 files changed, 205 insertions, 125 deletions
diff --git a/activesupport/lib/active_support/callbacks.rb b/activesupport/lib/active_support/callbacks.rb index 5c738572a8..0d5035f637 100644 --- a/activesupport/lib/active_support/callbacks.rb +++ b/activesupport/lib/active_support/callbacks.rb @@ -4,17 +4,18 @@ require 'active_support/core_ext/array/extract_options' require 'active_support/core_ext/class/attribute' require 'active_support/core_ext/kernel/reporting' require 'active_support/core_ext/kernel/singleton_class' +require 'active_support/core_ext/string/filters' require 'thread' module ActiveSupport - # Callbacks are code hooks that are run at key points in an object's lifecycle. + # Callbacks are code hooks that are run at key points in an object's life cycle. # The typical use case is to have a base class define a set of callbacks # relevant to the other functionality it supplies, so that subclasses can # install callbacks that enhance or modify the base functionality without # needing to override or redefine methods of the base class. # # Mixing in this module allows you to define the events in the object's - # lifecycle that will support callbacks (via +ClassMethods.define_callbacks+), + # life cycle that will support callbacks (via +ClassMethods.define_callbacks+), # set the instance methods, procs, or callback objects to be called (via # +ClassMethods.set_callback+), and run the installed callbacks at the # appropriate times (via +run_callbacks+). @@ -71,25 +72,29 @@ module ActiveSupport # order. # # If the callback chain was halted, returns +false+. Otherwise returns the - # result of the block, or +true+ if no block is given. + # result of the block, +nil+ if no callbacks have been set, or +true+ + # if callbacks have been set but no block is given. # # run_callbacks :save do # save # end def run_callbacks(kind, &block) - cbs = send("_#{kind}_callbacks") - if cbs.empty? - yield if block_given? + send "_run_#{kind}_callbacks", &block + end + + private + + def _run_callbacks(callbacks, &block) + if callbacks.empty? + block.call if block else - runner = cbs.compile + runner = callbacks.compile e = Filters::Environment.new(self, false, nil, block) runner.call(e).value end end - private - - # A hook invoked everytime a before callback is halted. + # A hook invoked every time a before callback is halted. # This can be overridden in AS::Callback implementors in order # to provide better debugging/logging. def halted_callback_hook(filter) @@ -117,102 +122,106 @@ module ActiveSupport ENDING = End.new class Before - def self.build(next_callback, user_callback, user_conditions, chain_config, filter) + def self.build(callback_sequence, user_callback, user_conditions, chain_config, filter) halted_lambda = chain_config[:terminator] if chain_config.key?(:terminator) && user_conditions.any? - halting_and_conditional(next_callback, user_callback, user_conditions, halted_lambda, filter) + halting_and_conditional(callback_sequence, user_callback, user_conditions, halted_lambda, filter) elsif chain_config.key? :terminator - halting(next_callback, user_callback, halted_lambda, filter) + halting(callback_sequence, user_callback, halted_lambda, filter) elsif user_conditions.any? - conditional(next_callback, user_callback, user_conditions) + conditional(callback_sequence, user_callback, user_conditions) else - simple next_callback, user_callback + simple callback_sequence, user_callback end end - private - - def self.halting_and_conditional(next_callback, user_callback, user_conditions, halted_lambda, filter) - lambda { |env| + def self.halting_and_conditional(callback_sequence, user_callback, user_conditions, halted_lambda, filter) + callback_sequence.before do |env| target = env.target value = env.value halted = env.halted if !halted && user_conditions.all? { |c| c.call(target, value) } - result = user_callback.call target, value - env.halted = halted_lambda.call(target, result) + result_lambda = -> { user_callback.call target, value } + env.halted = halted_lambda.call(target, result_lambda) if env.halted target.send :halted_callback_hook, filter end end - next_callback.call env - } + + env + end end + private_class_method :halting_and_conditional - def self.halting(next_callback, user_callback, halted_lambda, filter) - lambda { |env| + def self.halting(callback_sequence, user_callback, halted_lambda, filter) + callback_sequence.before do |env| target = env.target value = env.value halted = env.halted unless halted - result = user_callback.call target, value - env.halted = halted_lambda.call(target, result) + result_lambda = -> { user_callback.call target, value } + env.halted = halted_lambda.call(target, result_lambda) + if env.halted target.send :halted_callback_hook, filter end end - next_callback.call env - } + + env + end end + private_class_method :halting - def self.conditional(next_callback, user_callback, user_conditions) - lambda { |env| + def self.conditional(callback_sequence, user_callback, user_conditions) + callback_sequence.before do |env| target = env.target value = env.value if user_conditions.all? { |c| c.call(target, value) } user_callback.call target, value end - next_callback.call env - } + + env + end end + private_class_method :conditional - def self.simple(next_callback, user_callback) - lambda { |env| + def self.simple(callback_sequence, user_callback) + callback_sequence.before do |env| user_callback.call env.target, env.value - next_callback.call env - } + + env + end end + private_class_method :simple end class After - def self.build(next_callback, user_callback, user_conditions, chain_config) + def self.build(callback_sequence, user_callback, user_conditions, chain_config) if chain_config[:skip_after_callbacks_if_terminated] if chain_config.key?(:terminator) && user_conditions.any? - halting_and_conditional(next_callback, user_callback, user_conditions) + halting_and_conditional(callback_sequence, user_callback, user_conditions) elsif chain_config.key?(:terminator) - halting(next_callback, user_callback) + halting(callback_sequence, user_callback) elsif user_conditions.any? - conditional next_callback, user_callback, user_conditions + conditional callback_sequence, user_callback, user_conditions else - simple next_callback, user_callback + simple callback_sequence, user_callback end else if user_conditions.any? - conditional next_callback, user_callback, user_conditions + conditional callback_sequence, user_callback, user_conditions else - simple next_callback, user_callback + simple callback_sequence, user_callback end end end - private - - def self.halting_and_conditional(next_callback, user_callback, user_conditions) - lambda { |env| - env = next_callback.call env + def self.halting_and_conditional(callback_sequence, user_callback, user_conditions) + callback_sequence.after do |env| target = env.target value = env.value halted = env.halted @@ -220,118 +229,126 @@ module ActiveSupport if !halted && user_conditions.all? { |c| c.call(target, value) } user_callback.call target, value end + env - } + end end + private_class_method :halting_and_conditional - def self.halting(next_callback, user_callback) - lambda { |env| - env = next_callback.call env + def self.halting(callback_sequence, user_callback) + callback_sequence.after do |env| unless env.halted user_callback.call env.target, env.value end + env - } + end end + private_class_method :halting - def self.conditional(next_callback, user_callback, user_conditions) - lambda { |env| - env = next_callback.call env + def self.conditional(callback_sequence, user_callback, user_conditions) + callback_sequence.after do |env| target = env.target value = env.value if user_conditions.all? { |c| c.call(target, value) } user_callback.call target, value end + env - } + end end + private_class_method :conditional - def self.simple(next_callback, user_callback) - lambda { |env| - env = next_callback.call env + def self.simple(callback_sequence, user_callback) + callback_sequence.after do |env| user_callback.call env.target, env.value + env - } + end end + private_class_method :simple end class Around - def self.build(next_callback, user_callback, user_conditions, chain_config) + def self.build(callback_sequence, user_callback, user_conditions, chain_config) if chain_config.key?(:terminator) && user_conditions.any? - halting_and_conditional(next_callback, user_callback, user_conditions) + halting_and_conditional(callback_sequence, user_callback, user_conditions) elsif chain_config.key? :terminator - halting(next_callback, user_callback) + halting(callback_sequence, user_callback) elsif user_conditions.any? - conditional(next_callback, user_callback, user_conditions) + conditional(callback_sequence, user_callback, user_conditions) else - simple(next_callback, user_callback) + simple(callback_sequence, user_callback) end end - private - - def self.halting_and_conditional(next_callback, user_callback, user_conditions) - lambda { |env| + def self.halting_and_conditional(callback_sequence, user_callback, user_conditions) + callback_sequence.around do |env, &run| target = env.target value = env.value halted = env.halted if !halted && user_conditions.all? { |c| c.call(target, value) } user_callback.call(target, value) { - env = next_callback.call env + env = run.call env env.value } + env else - next_callback.call env + run.call env end - } + end end + private_class_method :halting_and_conditional - def self.halting(next_callback, user_callback) - lambda { |env| + def self.halting(callback_sequence, user_callback) + callback_sequence.around do |env, &run| target = env.target value = env.value - unless env.halted + if env.halted + run.call env + else user_callback.call(target, value) { - env = next_callback.call env + env = run.call env env.value } env - else - next_callback.call env end - } + end end + private_class_method :halting - def self.conditional(next_callback, user_callback, user_conditions) - lambda { |env| + def self.conditional(callback_sequence, user_callback, user_conditions) + callback_sequence.around do |env, &run| target = env.target value = env.value if user_conditions.all? { |c| c.call(target, value) } user_callback.call(target, value) { - env = next_callback.call env + env = run.call env env.value } env else - next_callback.call env + run.call env end - } + end end + private_class_method :conditional - def self.simple(next_callback, user_callback) - lambda { |env| + def self.simple(callback_sequence, user_callback) + callback_sequence.around do |env, &run| user_callback.call(env.target, env.value) { - env = next_callback.call env + env = run.call env env.value } env - } + end end + private_class_method :simple end end @@ -356,14 +373,14 @@ module ActiveSupport def filter; @key; end def raw_filter; @filter; end - def merge(chain, new_options) + def merge_conditional_options(chain, if_option:, unless_option:) options = { :if => @if.dup, :unless => @unless.dup } - options[:if].concat Array(new_options.fetch(:unless, [])) - options[:unless].concat Array(new_options.fetch(:if, [])) + options[:if].concat Array(unless_option) + options[:unless].concat Array(if_option) self.class.build chain, @filter, @kind, options end @@ -382,17 +399,17 @@ module ActiveSupport end # Wraps code with filter - def apply(next_callback) + def apply(callback_sequence) user_conditions = conditions_lambdas user_callback = make_lambda @filter case kind when :before - Filters::Before.build(next_callback, user_callback, user_conditions, chain_config, @filter) + Filters::Before.build(callback_sequence, user_callback, user_conditions, chain_config, @filter) when :after - Filters::After.build(next_callback, user_callback, user_conditions, chain_config) + Filters::After.build(callback_sequence, user_callback, user_conditions, chain_config) when :around - Filters::Around.build(next_callback, user_callback, user_conditions, chain_config) + Filters::Around.build(callback_sequence, user_callback, user_conditions, chain_config) end end @@ -409,15 +426,8 @@ module ActiveSupport # Procs:: A proc to call with the object. # Objects:: An object with a <tt>before_foo</tt> method on it to call. # - # All of these objects are compiled into methods and handled - # the same after this point: - # - # Symbols:: Already methods. - # Strings:: class_eval'd into methods. - # Procs:: using define_method compiled into methods. - # Objects:: - # a method is created that calls the before_foo method - # on the object. + # All of these objects are converted into a lambda and handled + # the same after this point. def make_lambda(filter) case filter when Symbol @@ -464,16 +474,59 @@ module ActiveSupport end end + # Execute before and after filters in a sequence instead of + # chaining them with nested lambda calls, see: + # https://github.com/rails/rails/issues/18011 + class CallbackSequence + def initialize(&call) + @call = call + @before = [] + @after = [] + end + + def before(&before) + @before.unshift(before) + self + end + + def after(&after) + @after.push(after) + self + end + + def around(&around) + CallbackSequence.new do |*args| + around.call(*args) { + self.call(*args) + } + end + end + + def call(*args) + @before.each { |b| b.call(*args) } + value = @call.call(*args) + @after.each { |a| a.call(*args) } + value + end + end + # An Array with a compile method. class CallbackChain #:nodoc:# include Enumerable attr_reader :name, :config + # If true, any callback returning +false+ will halt the entire callback + # chain and display a deprecation message. If false, callback chains will + # only be halted by calling +throw :abort+. Defaults to +true+. + class_attribute :halt_and_display_warning_on_return_false + self.halt_and_display_warning_on_return_false = true + def initialize(name, config) @name = name @config = { - :scope => [ :kind ] + scope: [:kind], + terminator: default_terminator }.merge!(config) @chain = [] @callbacks = nil @@ -508,8 +561,9 @@ module ActiveSupport def compile @callbacks || @mutex.synchronize do - @callbacks ||= @chain.reverse.inject(Filters::ENDING) do |chain, callback| - callback.apply chain + final_sequence = CallbackSequence.new { |env| Filters::ENDING.call(env) } + @callbacks ||= @chain.reverse.inject(final_sequence) do |callback_sequence, callback| + callback.apply callback_sequence end end end @@ -543,6 +597,28 @@ module ActiveSupport @callbacks = nil @chain.delete_if { |c| callback.duplicates?(c) } end + + def default_terminator + Proc.new do |target, result_lambda| + terminate = true + catch(:abort) do + result = result_lambda.call if result_lambda.is_a?(Proc) + if halt_and_display_warning_on_return_false && result == false + display_deprecation_warning_for_false_terminator + else + terminate = false + end + end + terminate + end + end + + def display_deprecation_warning_for_false_terminator + ActiveSupport::Deprecation.warn(<<-MSG.squish) + Returning `false` in a callback will not implicitly halt a callback chain in the next release of Rails. + To explicitly halt a callback chain, please use `throw :abort` instead. + MSG + end end module ClassMethods @@ -556,7 +632,7 @@ module ActiveSupport # This is used internally to append, prepend and skip callbacks to the # CallbackChain. def __update_callbacks(name) #:nodoc: - ([self] + ActiveSupport::DescendantsTracker.descendants(self)).reverse.each do |target| + ([self] + ActiveSupport::DescendantsTracker.descendants(self)).reverse_each do |target| chain = target.get_callbacks name yield target, chain.dup end @@ -566,7 +642,7 @@ module ActiveSupport # # set_callback :save, :before, :before_meth # set_callback :save, :after, :after_meth, if: :condition - # set_callback :save, :around, ->(r, &block) { stuff; result = block.call; stuff } + # set_callback :save, :around, ->(r, block) { stuff; result = block.call; stuff } # # The second arguments indicates whether the callback is to be run +:before+, # +:after+, or +:around+ the event. If omitted, +:before+ is assumed. This @@ -574,10 +650,10 @@ module ActiveSupport # # set_callback :save, :before_meth # - # The callback can specified as a symbol naming an instance method; as a + # The callback can be specified as a symbol naming an instance method; as a # proc, lambda, or block; as a string to be instance evaluated; or as an # object that responds to a certain method determined by the <tt>:scope</tt> - # argument to +define_callback+. + # argument to +define_callbacks+. # # If a proc, lambda, or block is given, its body is evaluated in the context # of the current object. It can also optionally accept the current object as @@ -625,7 +701,7 @@ module ActiveSupport filter = chain.find {|c| c.matches?(type, filter) } if filter && options.any? - new_filter = filter.merge(chain, options) + new_filter = filter.merge_conditional_options(chain, if_option: options[:if], unless_option: options[:unless]) chain.insert(chain.index(filter), new_filter) end @@ -648,7 +724,7 @@ module ActiveSupport self.set_callbacks name, callbacks.dup.clear end - # Define sets of events in the object lifecycle that support callbacks. + # Define sets of events in the object life cycle that support callbacks. # # define_callbacks :validate # define_callbacks :initialize, :save, :destroy @@ -656,16 +732,17 @@ module ActiveSupport # ===== Options # # * <tt>:terminator</tt> - Determines when a before filter will halt the - # callback chain, preventing following callbacks from being called and - # the event from being triggered. This should be a lambda to be executed. + # callback chain, preventing following before and around callbacks from + # being called and the event from being triggered. + # This should be a lambda to be executed. # The current object and the return result of the callback will be called # with the lambda. # # define_callbacks :validate, terminator: ->(target, result) { result == false } # # In this example, if any before validate callbacks returns +false+, - # other callbacks are not executed. Defaults to +false+, meaning no value - # halts the chain. + # any successive before and around callback is not executed. + # Defaults to +false+, meaning no value halts the chain. # # * <tt>:skip_after_callbacks_if_terminated</tt> - Determines if after # callbacks should be terminated by the <tt>:terminator</tt> option. By @@ -716,18 +793,21 @@ module ActiveSupport # define_callbacks :save, scope: [:name] # # would call <tt>Audit#save</tt>. + # + # NOTE: +method_name+ passed to `define_model_callbacks` must not end with + # `!`, `?` or `=`. def define_callbacks(*names) options = names.extract_options! - if options.key?(:terminator) && String === options[:terminator] - ActiveSupport::Deprecation.warn "String based terminators are deprecated, please use a lambda" - value = options[:terminator] - line = class_eval "lambda { |result| #{value} }", __FILE__, __LINE__ - options[:terminator] = lambda { |target, result| target.instance_exec(result, &line) } - end names.each do |name| class_attribute "_#{name}_callbacks" set_callbacks name, CallbackChain.new(name, options) + + module_eval <<-RUBY, __FILE__, __LINE__ + 1 + def _run_#{name}_callbacks(&block) + _run_callbacks(_#{name}_callbacks, &block) + end + RUBY end end |