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rails--rails/actionpack/lib/action_controller/routing/optimisations.rb
2008-11-26 10:52:05 +01:00

130 lines
4.4 KiB
Ruby

module ActionController
module Routing
# Much of the slow performance from routes comes from the
# complexity of expiry, <tt>:requirements</tt> matching, defaults providing
# and figuring out which url pattern to use. With named routes
# we can avoid the expense of finding the right route. So if
# they've provided the right number of arguments, and have no
# <tt>:requirements</tt>, we can just build up a string and return it.
#
# To support building optimisations for other common cases, the
# generation code is separated into several classes
module Optimisation
def generate_optimisation_block(route, kind)
return "" unless route.optimise?
OPTIMISERS.inject("") do |memo, klazz|
memo << klazz.new(route, kind).source_code
memo
end
end
class Optimiser
attr_reader :route, :kind
GLOBAL_GUARD_CONDITIONS = [
"(!defined?(default_url_options) || default_url_options.blank?)",
"(!defined?(controller.default_url_options) || controller.default_url_options.blank?)",
"defined?(request)",
"request"
]
def initialize(route, kind)
@route = route
@kind = kind
end
def guard_conditions
["false"]
end
def generation_code
'nil'
end
def source_code
if applicable?
guard_condition = (GLOBAL_GUARD_CONDITIONS + guard_conditions).join(" && ")
"return #{generation_code} if #{guard_condition}\n"
else
"\n"
end
end
# Temporarily disabled <tt>:url</tt> optimisation pending proper solution to
# Issues around request.host etc.
def applicable?
true
end
end
# Given a route
#
# map.person '/people/:id'
#
# If the user calls <tt>person_url(@person)</tt>, we can simply
# return a string like "/people/#{@person.to_param}"
# rather than triggering the expensive logic in +url_for+.
class PositionalArguments < Optimiser
def guard_conditions
number_of_arguments = route.required_segment_keys.size
# if they're using foo_url(:id=>2) it's one
# argument, but we don't want to generate /foos/id2
if number_of_arguments == 1
["args.size == 1", "!args.first.is_a?(Hash)"]
else
["args.size == #{number_of_arguments}"]
end
end
def generation_code
elements = []
idx = 0
if kind == :url
elements << '#{request.protocol}'
elements << '#{request.host_with_port}'
end
elements << '#{ActionController::Base.relative_url_root if ActionController::Base.relative_url_root}'
# The last entry in <tt>route.segments</tt> appears to *always* be a
# 'divider segment' for '/' but we have assertions to ensure that
# we don't include the trailing slashes, so skip them.
(route.segments.size == 1 ? route.segments : route.segments[0..-2]).each do |segment|
if segment.is_a?(DynamicSegment)
elements << segment.interpolation_chunk("args[#{idx}].to_param")
idx += 1
else
elements << segment.interpolation_chunk
end
end
%("#{elements * ''}")
end
end
# This case is mostly the same as the positional arguments case
# above, but it supports additional query parameters as the last
# argument
class PositionalArgumentsWithAdditionalParams < PositionalArguments
def guard_conditions
["args.size == #{route.segment_keys.size + 1}"] +
UrlRewriter::RESERVED_OPTIONS.collect{ |key| "!args.last.has_key?(:#{key})" }
end
# This case uses almost the same code as positional arguments,
# but add a question mark and args.last.to_query on the end,
# unless the last arg is empty
def generation_code
super.insert(-2, '#{\'?\' + args.last.to_query unless args.last.empty?}')
end
# To avoid generating "http://localhost/?host=foo.example.com" we
# can't use this optimisation on routes without any segments
def applicable?
super && route.segment_keys.size > 0
end
end
OPTIMISERS = [PositionalArguments, PositionalArgumentsWithAdditionalParams]
end
end
end