443 lines
14 KiB
Ruby
443 lines
14 KiB
Ruby
require File.join(File.dirname(__FILE__), '..', 'support', 'class')
|
|
|
|
# Extracted from ActiveSupport::Callbacks written by Yehuda Katz
|
|
# http://github.com/wycats/rails/raw/18b405f154868204a8f332888871041a7bad95e1/activesupport/lib/active_support/callbacks.rb
|
|
|
|
module CouchRest
|
|
# Callbacks are hooks into the lifecycle of an object that allow you to trigger logic
|
|
# before or after an alteration of the object state.
|
|
#
|
|
# Mixing in this module allows you to define callbacks in your class.
|
|
#
|
|
# Example:
|
|
# class Storage
|
|
# include CouchRest::Callbacks
|
|
#
|
|
# define_callbacks :save
|
|
# end
|
|
#
|
|
# class ConfigStorage < Storage
|
|
# save_callback :before, :saving_message
|
|
# def saving_message
|
|
# puts "saving..."
|
|
# end
|
|
#
|
|
# save_callback :after do |object|
|
|
# puts "saved"
|
|
# end
|
|
#
|
|
# def save
|
|
# _run_save_callbacks do
|
|
# puts "- save"
|
|
# end
|
|
# end
|
|
# end
|
|
#
|
|
# config = ConfigStorage.new
|
|
# config.save
|
|
#
|
|
# Output:
|
|
# saving...
|
|
# - save
|
|
# saved
|
|
#
|
|
# Callbacks from parent classes are inherited.
|
|
#
|
|
# Example:
|
|
# class Storage
|
|
# include CouchRest::Callbacks
|
|
#
|
|
# define_callbacks :save
|
|
#
|
|
# save_callback :before, :prepare
|
|
# def prepare
|
|
# puts "preparing save"
|
|
# end
|
|
# end
|
|
#
|
|
# class ConfigStorage < Storage
|
|
# save_callback :before, :saving_message
|
|
# def saving_message
|
|
# puts "saving..."
|
|
# end
|
|
#
|
|
# save_callback :after do |object|
|
|
# puts "saved"
|
|
# end
|
|
#
|
|
# def save
|
|
# _run_save_callbacks do
|
|
# puts "- save"
|
|
# end
|
|
# end
|
|
# end
|
|
#
|
|
# config = ConfigStorage.new
|
|
# config.save
|
|
#
|
|
# Output:
|
|
# preparing save
|
|
# saving...
|
|
# - save
|
|
# saved
|
|
module Callbacks
|
|
def self.included(klass)
|
|
klass.extend ClassMethods
|
|
end
|
|
|
|
def run_callbacks(kind, options = {})
|
|
send("_run_#{kind}_callbacks")
|
|
end
|
|
|
|
class Callback
|
|
@@_callback_sequence = 0
|
|
|
|
attr_accessor :filter, :kind, :name, :options, :per_key, :klass
|
|
def initialize(filter, kind, options, klass, name)
|
|
@kind, @klass = kind, klass
|
|
@name = name
|
|
|
|
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(klass)
|
|
obj = super()
|
|
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 normalize_options!(options)
|
|
options[:if] = Array(options[:if])
|
|
options[:unless] = Array(options[:unless])
|
|
|
|
options[:per_key] ||= {}
|
|
options[:per_key][:if] = Array(options[:per_key][:if])
|
|
options[:per_key][:unless] = Array(options[:per_key][:unless])
|
|
end
|
|
|
|
def next_id
|
|
@@_callback_sequence += 1
|
|
end
|
|
|
|
def matches?(_kind, _name, _filter)
|
|
@kind == _kind &&
|
|
@name == _name &&
|
|
@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
|
|
RUBY_EVAL
|
|
end
|
|
|
|
# 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
|
|
[@compiled_options[0], @filter, @compiled_options[1]].compact.join("\n")
|
|
elsif @compiled_options[0]
|
|
# 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 = <<-RUBY_EVAL
|
|
def #{name}
|
|
#{@compiled_options[0]}
|
|
#{@filter} do
|
|
yield self
|
|
end
|
|
else
|
|
yield self
|
|
end
|
|
end
|
|
RUBY_EVAL
|
|
@klass.class_eval(txt)
|
|
"#{name} do"
|
|
else
|
|
"#{@filter} do"
|
|
end
|
|
end
|
|
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}?")
|
|
|
|
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
|
|
# 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(_compile_filter(options[:if]))
|
|
end
|
|
|
|
unless options[:unless].empty?
|
|
conditions << Array(_compile_filter(options[:unless])).map {|f| "!#{f}"}
|
|
end
|
|
|
|
["if #{conditions.flatten.join(" && ")}", "end"]
|
|
end
|
|
|
|
# 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 Proc
|
|
@klass.send(:define_method, method_name, &filter)
|
|
method_name << (filter.arity == 1 ? "(self)" : "")
|
|
when String
|
|
@klass.class_eval <<-RUBY_EVAL
|
|
def #{method_name}
|
|
#{filter}
|
|
end
|
|
RUBY_EVAL
|
|
method_name
|
|
else
|
|
kind, name = @kind, @name
|
|
@klass.send(:define_method, method_name) do
|
|
filter.send("#{kind}_#{name}", self)
|
|
end
|
|
method_name
|
|
end
|
|
end
|
|
end
|
|
|
|
# This method_missing is supplied to catch callbacks with keys and create
|
|
# the appropriate callback for future use.
|
|
def method_missing(meth, *args, &blk)
|
|
if meth.to_s =~ /_run_(\w+)_(\w+)_(\w+)_callbacks/
|
|
return self.class._create_and_run_keyed_callback($1, $2.to_sym, $3.to_sym, self, &blk)
|
|
end
|
|
super
|
|
end
|
|
|
|
# An Array with a compile method
|
|
class CallbackChain < Array
|
|
def compile(key = nil, object = nil)
|
|
method = []
|
|
each do |callback|
|
|
method << callback.start(key, object)
|
|
end
|
|
method << "yield self"
|
|
reverse_each do |callback|
|
|
method << callback.end(key, object)
|
|
end
|
|
method.compact.join("\n")
|
|
end
|
|
|
|
def clone(klass)
|
|
CallbackChain.new(map {|c| c.clone(klass)})
|
|
end
|
|
end
|
|
|
|
module ClassMethods
|
|
CHAINS = {:before => :before, :around => :before, :after => :after} unless self.const_defined?("CHAINS")
|
|
|
|
# Make the _run_save_callbacks 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_save_callbacks do
|
|
# save
|
|
# end
|
|
#
|
|
# The _run_save_callbacks 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, str, options)
|
|
self.class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
|
|
def _run_#{symbol}_callbacks(key = nil)
|
|
if key
|
|
send("_run_\#{self.class}_#{symbol}_\#{key}_callbacks") { yield }
|
|
else
|
|
#{str}
|
|
end
|
|
end
|
|
RUBY_EVAL
|
|
|
|
before_name, around_name, after_name =
|
|
options.values_at(:before, :after, :around)
|
|
end
|
|
|
|
# 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_and_run_keyed_callback(klass, kind, key, obj, &blk)
|
|
@_keyed_callbacks ||= {}
|
|
@_keyed_callbacks[[kind, key]] ||= begin
|
|
str = self.send("_#{kind}_callbacks").compile(key, obj)
|
|
self.class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
|
|
def _run_#{klass}_#{kind}_#{key}_callbacks
|
|
#{str}
|
|
end
|
|
RUBY_EVAL
|
|
true
|
|
end
|
|
obj.send("_run_#{klass}_#{kind}_#{key}_callbacks", &blk)
|
|
end
|
|
|
|
# Define callbacks.
|
|
#
|
|
# Creates a <name>_callback method that you can use to add callbacks.
|
|
#
|
|
# Syntax:
|
|
# save_callback :before, :before_meth
|
|
# save_callback :after, :after_meth, :if => :condition
|
|
# save_callback :around {|r| stuff; yield; stuff }
|
|
#
|
|
# The <name>_callback method also updates the _run_<name>_callbacks
|
|
# method, which is the public API to run the callbacks.
|
|
#
|
|
# Also creates a skip_<name>_callback method that you can use to skip
|
|
# callbacks.
|
|
#
|
|
# 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_dispatch_callbacks(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 define_callbacks(*symbols)
|
|
symbols.each do |symbol|
|
|
self.class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
|
|
class_inheritable_accessor :_#{symbol}_callbacks
|
|
self._#{symbol}_callbacks = CallbackChain.new
|
|
|
|
def self.#{symbol}_callback(type, *filters, &blk)
|
|
options = filters.last.is_a?(Hash) ? filters.pop : {}
|
|
filters.unshift(blk) if block_given?
|
|
filters.map! {|f| Callback.new(f, type, options.dup, self, :#{symbol})}
|
|
self._#{symbol}_callbacks.push(*filters)
|
|
_define_runner(:#{symbol}, self._#{symbol}_callbacks.compile, options)
|
|
end
|
|
|
|
def self.skip_#{symbol}_callback(type, *filters, &blk)
|
|
options = filters.last.is_a?(Hash) ? filters.pop : {}
|
|
filters.unshift(blk) if block_given?
|
|
filters.each do |filter|
|
|
self._#{symbol}_callbacks = self._#{symbol}_callbacks.clone(self)
|
|
|
|
filter = self._#{symbol}_callbacks.find {|c| c.matches?(type, :#{symbol}, filter) }
|
|
per_key = options[:per_key] || {}
|
|
if filter
|
|
filter.recompile!(options, per_key)
|
|
else
|
|
self._#{symbol}_callbacks.delete(filter)
|
|
end
|
|
_define_runner(:#{symbol}, self._#{symbol}_callbacks.compile, options)
|
|
end
|
|
|
|
end
|
|
|
|
self.#{symbol}_callback(:before)
|
|
RUBY_EVAL
|
|
end
|
|
end
|
|
end
|
|
end
|
|
end
|