--- /dev/null
+module ActionController
+ module Routing
+ # BEFORE: 0.191446860631307 ms/url
+ # AFTER: 0.029847304022858 ms/url
+ # Speed up: 6.4 times
+ #
+ # Route recognition is slow due to one-by-one iterating over
+ # a whole routeset (each map.resources generates at least 14 routes)
+ # and matching weird regexps on each step.
+ #
+ # We optimize this by skipping all URI segments that 100% sure can't
+ # be matched, moving deeper in a tree of routes (where node == segment)
+ # until first possible match is accured. In such case, we start walking
+ # a flat list of routes, matching them with accurate matcher.
+ # So, first step: search a segment tree for the first relevant index.
+ # Second step: iterate routes starting with that index.
+ #
+ # How tree is walked? We can do a recursive tests, but it's smarter:
+ # We just create a tree of if-s and elsif-s matching segments.
+ #
+ # We have segments of 3 flavors:
+ # 1) nil (no segment, route finished)
+ # 2) const-dot-dynamic (like "/posts.:xml", "/preview.:size.jpg")
+ # 3) const (like "/posts", "/comments")
+ # 4) dynamic ("/:id", "file.:size.:extension")
+ #
+ # We split incoming string into segments and iterate over them.
+ # When segment is nil, we drop immediately, on a current node index.
+ # When segment is equal to some const, we step into branch.
+ # If none constants matched, we step into 'dynamic' branch (it's a last).
+ # If we can't match anything, we drop to last index on a level.
+ #
+ # Note: we maintain the original routes order, so we finish building
+ # steps on a first dynamic segment.
+ #
+ #
+ # Example. Given the routes:
+ # 0 /posts/
+ # 1 /posts/:id
+ # 2 /posts/:id/comments
+ # 3 /posts/blah
+ # 4 /users/
+ # 5 /users/:id
+ # 6 /users/:id/profile
+ #
+ # request_uri = /users/123
+ #
+ # There will be only 4 iterations:
+ # 1) segm test for /posts prefix, skip all /posts/* routes
+ # 2) segm test for /users/
+ # 3) segm test for /users/:id
+ # (jump to list index = 5)
+ # 4) full test for /users/:id => here we are!
+ class RouteSet
+ def recognize_path(path, environment={})
+ result = recognize_optimized(path, environment) and return result
+
+ # Route was not recognized. Try to find out why (maybe wrong verb).
+ allows = HTTP_METHODS.select { |verb| routes.find { |r| r.recognize(path, :method => verb) } }
+
+ if environment[:method] && !HTTP_METHODS.include?(environment[:method])
+ raise NotImplemented.new(*allows)
+ elsif !allows.empty?
+ raise MethodNotAllowed.new(*allows)
+ else
+ raise RoutingError, "No route matches #{path.inspect} with #{environment.inspect}"
+ end
+ end
+
+ def segment_tree(routes)
+ tree = [0]
+
+ i = -1
+ routes.each do |route|
+ i += 1
+ # not fast, but runs only once
+ segments = to_plain_segments(route.segments.inject("") { |str,s| str << s.to_s })
+
+ node = tree
+ segments.each do |seg|
+ seg = :dynamic if seg && seg[0] == ?:
+ node << [seg, [i]] if node.empty? || node[node.size - 1][0] != seg
+ node = node[node.size - 1][1]
+ end
+ end
+ tree
+ end
+
+ def generate_code(list, padding=' ', level = 0)
+ # a digit
+ return padding + "#{list[0]}\n" if list.size == 1 && !(Array === list[0])
+
+ body = padding + "(seg = segments[#{level}]; \n"
+
+ i = 0
+ was_nil = false
+ list.each do |item|
+ if Array === item
+ i += 1
+ start = (i == 1)
+ final = (i == list.size)
+ tag, sub = item
+ if tag == :dynamic
+ body += padding + "#{start ? 'if' : 'elsif'} true\n"
+ body += generate_code(sub, padding + " ", level + 1)
+ break
+ elsif tag == nil && !was_nil
+ was_nil = true
+ body += padding + "#{start ? 'if' : 'elsif'} seg.nil?\n"
+ body += generate_code(sub, padding + " ", level + 1)
+ else
+ body += padding + "#{start ? 'if' : 'elsif'} seg == '#{tag}'\n"
+ body += generate_code(sub, padding + " ", level + 1)
+ end
+ end
+ end
+ body += padding + "else\n"
+ body += padding + " #{list[0]}\n"
+ body += padding + "end)\n"
+ body
+ end
+
+ # this must be really fast
+ def to_plain_segments(str)
+ str = str.dup
+ str.sub!(/^\/+/,'')
+ str.sub!(/\/+$/,'')
+ segments = str.split(/\.[^\/]+\/+|\/+|\.[^\/]+\Z/) # cut off ".format" also
+ segments << nil
+ segments
+ end
+
+ private
+ def write_recognize_optimized!
+ tree = segment_tree(routes)
+ body = generate_code(tree)
+
+ remove_recognize_optimized!
+
+ instance_eval %{
+ def recognize_optimized(path, env)
+ segments = to_plain_segments(path)
+ index = #{body}
+ return nil unless index
+ while index < routes.size
+ result = routes[index].recognize(path, env) and return result
+ index += 1
+ end
+ nil
+ end
+ }, '(recognize_optimized)', 1
+ end
+
+ def clear_recognize_optimized!
+ remove_recognize_optimized!
+ write_recognize_optimized!
+ end
+
+ def remove_recognize_optimized!
+ if respond_to?(:recognize_optimized)
+ class << self
+ remove_method :recognize_optimized
+ end
+ end
+ end
+ end
+ end
+end
projects / depot.git / blobdiff