require 'active_support/core_ext/array/wrap'
require 'active_support/core_ext/object/blank'
module ActionView
# 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:
mattr_accessor :fallbacks
@@fallbacks = [FileSystemResolver.new(""), FileSystemResolver.new("/")]
mattr_accessor :registered_details
self.registered_details = []
mattr_accessor :registered_detail_setters
self.registered_detail_setters = []
def self.register_detail(name, options = {}, &block)
self.registered_details << name
self.registered_detail_setters << [name, "#{name}="]
Accessors.send :define_method, :"_#{name}_defaults", &block
Accessors.module_eval <<-METHOD, __FILE__, __LINE__ + 1
def #{name}
@details[:#{name}]
end
def #{name}=(value)
value = Array.wrap(value.presence || _#{name}_defaults)
_set_detail(:#{name}, value) if value != @details[:#{name}]
end
METHOD
end
# Holds accessors for the registered details.
module Accessors #:nodoc:
end
register_detail(:formats) { Mime::SET.symbols }
register_detail(:locale) { [I18n.locale, I18n.default_locale] }
class DetailsKey #:nodoc:
alias :eql? :equal?
alias :object_hash :hash
attr_reader :hash
@details_keys = Hash.new
def self.get(details)
@details_keys[details.freeze] ||= new
end
def initialize
@hash = object_hash
end
end
def initialize(view_paths, details = {})
@details, @details_key = { :handlers => default_handlers }, nil
@frozen_formats, @skip_default_locale = false, false
self.view_paths = view_paths
self.registered_detail_setters.each do |key, setter|
send(setter, details[key])
end
end
module ViewPaths
attr_reader :view_paths
# 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::Base.process_view_paths(paths)
end
def find(name, prefix = nil, partial = false)
@view_paths.find(*args_for_lookup(name, prefix, partial))
end
alias :find_template :find
def find_all(name, prefix = nil, partial = false)
@view_paths.find_all(*args_for_lookup(name, prefix, partial))
end
def exists?(name, prefix = nil, partial = false)
@view_paths.exists?(*args_for_lookup(name, prefix, partial))
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, prefix, partial) #:nodoc:
name, prefix = normalize_name(name, prefix)
[name, prefix, partial || false, @details, details_key]
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, prefix) #:nodoc:
name = name.to_s.gsub(handlers_regexp, '')
parts = name.split('/')
return parts.pop, [prefix, *parts].compact.join("/")
end
def default_handlers #:nodoc:
@@default_handlers ||= Template::Handlers.extensions
end
def handlers_regexp #:nodoc:
@@handlers_regexp ||= /\.(?:#{default_handlers.join('|')})$/
end
end
module Details
# 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)
end
# Freeze the current formats in the lookup context. By freezing them, you are guaranteeing
# that next template lookups are not going to modify the formats. The controller can also
# use this, to ensure that formats won't be further modified (as it does in respond_to blocks).
def freeze_formats(formats, unless_frozen=false) #:nodoc:
return if unless_frozen && @frozen_formats
self.formats = formats
@frozen_formats = true
end
# Overload formats= to reject [:"*/*"] values.
def formats=(values)
if values && values.size == 1
value = values.first
values = nil if value == :"*/*"
values << :html if value == :js
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
# Overload 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 i18n_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?(:i18n_config) ? I18n.config.i18n_config : I18n.config
config.locale = value
end
super(@skip_default_locale ? I18n.locale : _locale_defaults)
end
# A method which only uses the first format in the formats array for layout lookup.
# This method plays straight with instance variables for performance reasons.
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, formats)
end
end
end
# Update the details keys by merging the given hash into the current
# details hash. If a block is given, the details are modified just during
# the execution of the block and reverted to the previous value after.
def update_details(new_details)
old_details = @details.dup
registered_detail_setters.each do |key, setter|
send(setter, new_details[key]) if new_details.key?(key)
end
begin
yield
ensure
@details_key = nil
@details = old_details
end
end
protected
def _set_detail(key, value)
@details_key = nil
@details = @details.dup if @details.frozen?
@details[key] = value.freeze
end
end
include Accessors
include Details
include ViewPaths
end
end
