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rails--rails/actionpack/lib/action_view/lookup_context.rb
thedarkone 45448a5788 Replace some global Hash usages with the new thread safe cache.
Summary of the changes:
 * Add thread_safe gem.
 * Use thread safe cache for digestor caching.
 * Replace manual synchronization with ThreadSafe::Cache in Relation::Delegation.
 * Replace @attribute_method_matchers_cache Hash with ThreadSafe::Cache.
 * Use TS::Cache to avoid the synchronisation overhead on listener retrieval.
 * Replace synchronisation with TS::Cache usage.
 * Use a preallocated array for performance/memory reasons.
 * Update the controllers cache to the new AS::Dependencies::ClassCache API.
   The original @controllers cache no longer makes much sense after @tenderlove's
   changes in 7b6bfe84f3 and f345e2380c.
 * Use TS::Cache in the connection pool to avoid locking overhead.
 * Use TS::Cache in ConnectionHandler.
2012-12-14 12:18:47 +01:00

234 lines
7.1 KiB
Ruby

require 'thread_safe'
require 'active_support/core_ext/module/remove_method'
module ActionView
# = Action View Lookup Context
#
# LookupContext is the object responsible to hold all information required to lookup
# templates, i.e. view paths and details. The LookupContext is also responsible to
# generate a key, given to view paths, used in the resolver cache lookup. Since
# this key is generated just once during the request, it speeds up all cache accesses.
class LookupContext #:nodoc:
attr_accessor :prefixes, :rendered_format
mattr_accessor :fallbacks
@@fallbacks = FallbackFileSystemResolver.instances
mattr_accessor :registered_details
self.registered_details = []
def self.register_detail(name, options = {}, &block)
self.registered_details << name
initialize = registered_details.map { |n| "@details[:#{n}] = details[:#{n}] || default_#{n}" }
Accessors.send :define_method, :"default_#{name}", &block
Accessors.module_eval <<-METHOD, __FILE__, __LINE__ + 1
def #{name}
@details.fetch(:#{name}, [])
end
def #{name}=(value)
value = value.present? ? Array(value) : default_#{name}
_set_detail(:#{name}, value) if value != @details[:#{name}]
end
remove_possible_method :initialize_details
def initialize_details(details)
#{initialize.join("\n")}
end
METHOD
end
# Holds accessors for the registered details.
module Accessors #:nodoc:
end
register_detail(:locale) { [I18n.locale, I18n.default_locale].uniq }
register_detail(:formats) { ActionView::Base.default_formats || [:html, :text, :js, :css, :xml, :json] }
register_detail(:handlers){ Template::Handlers.extensions }
class DetailsKey #:nodoc:
alias :eql? :equal?
alias :object_hash :hash
attr_reader :hash
@details_keys = ThreadSafe::Cache.new
def self.get(details)
@details_keys[details] ||= new
end
def self.clear
@details_keys.clear
end
def initialize
@hash = object_hash
end
end
# Add caching behavior on top of Details.
module DetailsCache
attr_accessor :cache
# Calculate the details key. Remove the handlers from calculation to improve performance
# since the user cannot modify it explicitly.
def details_key #:nodoc:
@details_key ||= DetailsKey.get(@details) if @cache
end
# Temporary skip passing the details_key forward.
def disable_cache
old_value, @cache = @cache, false
yield
ensure
@cache = old_value
end
protected
def _set_detail(key, value)
@details = @details.dup if @details_key
@details_key = nil
@details[key] = value
end
end
# Helpers related to template lookup using the lookup context information.
module ViewPaths
attr_reader :view_paths, :html_fallback_for_js
# Whenever setting view paths, makes a copy so we can manipulate then in
# instance objects as we wish.
def view_paths=(paths)
@view_paths = ActionView::PathSet.new(Array(paths))
end
def find(name, prefixes = [], partial = false, keys = [], options = {})
@view_paths.find(*args_for_lookup(name, prefixes, partial, keys, options))
end
alias :find_template :find
def find_all(name, prefixes = [], partial = false, keys = [], options = {})
@view_paths.find_all(*args_for_lookup(name, prefixes, partial, keys, options))
end
def exists?(name, prefixes = [], partial = false, keys = [], options = {})
@view_paths.exists?(*args_for_lookup(name, prefixes, partial, keys, options))
end
alias :template_exists? :exists?
# Add fallbacks to the view paths. Useful in cases you are rendering a :file.
def with_fallbacks
added_resolvers = 0
self.class.fallbacks.each do |resolver|
next if view_paths.include?(resolver)
view_paths.push(resolver)
added_resolvers += 1
end
yield
ensure
added_resolvers.times { view_paths.pop }
end
protected
def args_for_lookup(name, prefixes, partial, keys, details_options) #:nodoc:
name, prefixes = normalize_name(name, prefixes)
details, details_key = detail_args_for(details_options)
[name, prefixes, partial || false, details, details_key, keys]
end
# Compute details hash and key according to user options (e.g. passed from #render).
def detail_args_for(options)
return @details, details_key if options.empty? # most common path.
user_details = @details.merge(options)
[user_details, DetailsKey.get(user_details)]
end
# Support legacy foo.erb names even though we now ignore .erb
# as well as incorrectly putting part of the path in the template
# name instead of the prefix.
def normalize_name(name, prefixes) #:nodoc:
prefixes = prefixes.presence
parts = name.to_s.split('/')
parts.shift if parts.first.empty?
name = parts.pop
return name, prefixes || [""] if parts.empty?
parts = parts.join('/')
prefixes = prefixes ? prefixes.map { |p| "#{p}/#{parts}" } : [parts]
return name, prefixes
end
end
include Accessors
include DetailsCache
include ViewPaths
def initialize(view_paths, details = {}, prefixes = [])
@details, @details_key = {}, nil
@skip_default_locale = false
@cache = true
@prefixes = prefixes
@rendered_format = nil
self.view_paths = view_paths
initialize_details(details)
end
# Override formats= to expand ["*/*"] values and automatically
# add :html as fallback to :js.
def formats=(values)
if values
values.concat(default_formats) if values.delete "*/*"
if values == [:js]
values << :html
@html_fallback_for_js = true
end
end
super(values)
end
# Do not use the default locale on template lookup.
def skip_default_locale!
@skip_default_locale = true
self.locale = nil
end
# Override locale to return a symbol instead of array.
def locale
@details[:locale].first
end
# Overload locale= to also set the I18n.locale. If the current I18n.config object responds
# to original_config, it means that it's has a copy of the original I18n configuration and it's
# acting as proxy, which we need to skip.
def locale=(value)
if value
config = I18n.config.respond_to?(:original_config) ? I18n.config.original_config : I18n.config
config.locale = value
end
super(@skip_default_locale ? I18n.locale : default_locale)
end
# A method which only uses the first format in the formats array for layout lookup.
def with_layout_format
if formats.size == 1
yield
else
old_formats = formats
_set_detail(:formats, formats[0,1])
begin
yield
ensure
_set_detail(:formats, old_formats)
end
end
end
end
end