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:
attr_reader :details, :view_paths
class DetailsKey #:nodoc:
attr_reader :details
alias :eql? :equal?
@details_keys = Hash.new
def self.get(details)
@details_keys[details] ||= new(details)
end
def initialize(details)
@details, @hash = details, details.hash
end
end
def initialize(view_paths, details = {})
@details, @details_key = details, nil
self.view_paths = view_paths
end
# Shortcut to read formats from details.
def formats
@details[:formats]
end
# Shortcut to set formats in details.
def formats=(value)
self.details = @details.merge(:formats => Array(value))
end
# 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
# Setter for details. Everything this method is invoked, we need to nullify
# the details key if it changed.
def details=(details)
@details = details
@details_key = nil if @details_key && @details_key.details != details
end
def details_key
@details_key ||= DetailsKey.get(details) unless details.empty?
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 = self.details
self.details = old_details.merge(new_details)
if block_given?
begin
yield
ensure
self.details = old_details
end
end
end
def find_template(name, prefix = nil, partial = false)
@view_paths.find(name, details, prefix, partial || false, details_key)
end
def template_exists?(name, prefix = nil, partial = false)
@view_paths.exists?(name, details, prefix, partial || false, details_key)
end
end
end