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rails--rails/actionview/lib/action_view/lookup_context.rb
Kasper Timm Hansen 2bcf24795b
Merge pull request #37928 from CGA1123/fix-race-in-action-view
Make ActionView::LookupContext::DetailsKey thread-safe
2019-12-12 22:47:30 +01:00

315 lines
9.5 KiB
Ruby

# frozen_string_literal: true
require "concurrent/map"
require "active_support/core_ext/module/attribute_accessors"
require "action_view/template/resolver"
module ActionView
# = Action View Lookup Context
#
# <tt>LookupContext</tt> is the object responsible for holding all information
# required for looking up templates, i.e. view paths and details.
# <tt>LookupContext</tt> is also responsible for generating a key, given to
# view paths, used in the resolver cache lookup. Since this key is generated
# only once during the request, it speeds up all cache accesses.
class LookupContext #:nodoc:
attr_accessor :prefixes, :rendered_format
deprecate :rendered_format
deprecate :rendered_format=
mattr_accessor :fallbacks, default: FallbackFileSystemResolver.instances
mattr_accessor :registered_details, default: []
def self.register_detail(name, &block)
registered_details << name
Accessors::DEFAULT_PROCS[name] = block
Accessors.define_method(:"default_#{name}", &block)
Accessors.module_eval <<-METHOD, __FILE__, __LINE__ + 1
def #{name}
@details[:#{name}] || []
end
def #{name}=(value)
value = value.present? ? Array(value) : default_#{name}
_set_detail(:#{name}, value) if value != @details[:#{name}]
end
METHOD
end
# Holds accessors for the registered details.
module Accessors #:nodoc:
DEFAULT_PROCS = {}
end
register_detail(:locale) do
locales = [I18n.locale]
locales.concat(I18n.fallbacks[I18n.locale]) if I18n.respond_to? :fallbacks
locales << I18n.default_locale
locales.uniq!
locales
end
register_detail(:formats) { ActionView::Base.default_formats || [:html, :text, :js, :css, :xml, :json] }
register_detail(:variants) { [] }
register_detail(:handlers) { Template::Handlers.extensions }
class DetailsKey #:nodoc:
alias :eql? :equal?
@details_keys = Concurrent::Map.new
@digest_cache = Concurrent::Map.new
@view_context_mutex = Mutex.new
def self.digest_cache(details)
@digest_cache[details_cache_key(details)] ||= Concurrent::Map.new
end
def self.details_cache_key(details)
if details[:formats]
details = details.dup
details[:formats] &= Template::Types.symbols
end
@details_keys[details] ||= Object.new
end
def self.clear
ActionView::ViewPaths.all_view_paths.each do |path_set|
path_set.each(&:clear_cache)
end
ActionView::LookupContext.fallbacks.each(&:clear_cache)
@view_context_class = nil
@details_keys.clear
@digest_cache.clear
end
def self.digest_caches
@digest_cache.values
end
def self.view_context_class(klass)
@view_context_mutex.synchronize do
@view_context_class ||= klass.with_empty_template_cache
end
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.details_cache_key(@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
private
def _set_detail(key, value) # :doc:
@details = @details.dup if @digest_cache || @details_key
@digest_cache = nil
@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
def find(name, prefixes = [], partial = false, keys = [], options = {})
@view_paths.find(*args_for_lookup(name, prefixes, partial, keys, options))
end
alias :find_template :find
alias :find_file :find
deprecate :find_file
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?
def any?(name, prefixes = [], partial = false)
@view_paths.exists?(*args_for_any(name, prefixes, partial))
end
alias :any_templates? :any?
# Adds fallbacks to the view paths. Useful in cases when you are rendering
# a :file.
def with_fallbacks
view_paths = build_view_paths((@view_paths.paths + self.class.fallbacks).uniq)
if block_given?
ActiveSupport::Deprecation.warn <<~eowarn.squish
Calling `with_fallbacks` with a block is deprecated. Call methods on
the lookup context returned by `with_fallbacks` instead.
eowarn
begin
_view_paths = @view_paths
@view_paths = view_paths
yield
ensure
@view_paths = _view_paths
end
else
ActionView::LookupContext.new(view_paths, @details, @prefixes)
end
end
private
# Whenever setting view paths, makes a copy so that we can manipulate them in
# instance objects as we wish.
def build_view_paths(paths)
ActionView::PathSet.new(Array(paths))
end
def args_for_lookup(name, prefixes, partial, keys, details_options)
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) # :doc:
return @details, details_key if options.empty? # most common path.
user_details = @details.merge(options)
if @cache
details_key = DetailsKey.details_cache_key(user_details)
else
details_key = nil
end
[user_details, details_key]
end
def args_for_any(name, prefixes, partial)
name, prefixes = normalize_name(name, prefixes)
details, details_key = detail_args_for_any
[name, prefixes, partial || false, details, details_key]
end
def detail_args_for_any
@detail_args_for_any ||= begin
details = {}
registered_details.each do |k|
if k == :variants
details[k] = :any
else
details[k] = Accessors::DEFAULT_PROCS[k].call
end
end
if @cache
[details, DetailsKey.details_cache_key(details)]
else
[details, nil]
end
end
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)
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_key = nil
@digest_cache = nil
@cache = true
@prefixes = prefixes
@details = initialize_details({}, details)
@view_paths = build_view_paths(view_paths)
end
def digest_cache
@digest_cache ||= DetailsKey.digest_cache(@details)
end
def with_prepended_formats(formats)
details = @details.dup
details[:formats] = formats
self.class.new(@view_paths, details, @prefixes)
end
def initialize_details(target, details)
registered_details.each do |k|
target[k] = details[k] || Accessors::DEFAULT_PROCS[k].call
end
target
end
private :initialize_details
# Override formats= to expand ["*/*"] values and automatically
# add :html as fallback to :js.
def formats=(values)
if values
values = values.dup
values.concat(default_formats) if values.delete "*/*"
values.uniq!
invalid_values = (values - Template::Types.symbols)
unless invalid_values.empty?
raise ArgumentError, "Invalid formats: #{invalid_values.map(&:inspect).join(", ")}"
end
if values == [:js]
values << :html
@html_fallback_for_js = true
end
end
super(values)
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 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(default_locale)
end
end
end