Merge pull request rails#54491 from skipkayhil/hm-journey-bytes

Speed up GTG Simulator by reducing slices/matches

Author: byroot

actionpack/lib/action_dispatch/journey/gtg/simulator.rb

@@ -2,8 +2,6 @@
 
 # :markup: markdown
 
-require "strscan"
-
 module ActionDispatch
   module Journey # :nodoc:
     module GTG # :nodoc:
@@ -16,6 +14,12 @@ def initialize(memos)
       end
 
       class Simulator # :nodoc:
+        STATIC_TOKENS = Array.new(64)
+        STATIC_TOKENS[".".ord] = "."
+        STATIC_TOKENS["/".ord] = "/"
+        STATIC_TOKENS["?".ord] = "?"
+        STATIC_TOKENS.freeze
+
         INITIAL_STATE = [ [0, nil] ].freeze
 
         attr_reader :tt
@@ -25,16 +29,25 @@ def initialize(transition_table)
         end
 
         def memos(string)
-          input = StringScanner.new(string)
           state = INITIAL_STATE
-          start_index = 0
 
-          while sym = input.scan(%r([/.?]|[^/.?]+))
-            end_index = start_index + sym.length
+          pos = 0
+          eos = string.bytesize
+
+          while pos < eos
+            start_index = pos
+            pos += 1
 
-            state = tt.move(state, string, start_index, end_index)
+            if (token = STATIC_TOKENS[string.getbyte(start_index)])
+              state = tt.move(state, string, token, start_index, false)
+            else
+              while pos < eos && STATIC_TOKENS[string.getbyte(pos)].nil?
+                pos += 1
+              end
 
-            start_index = end_index
+              token = string.byteslice(start_index, pos - start_index)
+              state = tt.move(state, string, token, start_index, true)
+            end
           end
 
           acceptance_states = state.each_with_object([]) do |s_d, memos|

actionpack/lib/action_dispatch/journey/gtg/transition_table.rb

@@ -47,25 +47,22 @@ def eclosure(t)
           Array(t)
         end
 
-        def move(t, full_string, start_index, end_index)
+        def move(t, full_string, token, start_index, token_matches_default)
           return [] if t.empty?
 
           next_states = []
 
-          tok = full_string.slice(start_index, end_index - start_index)
-          token_matches_default_component = DEFAULT_EXP_ANCHORED.match?(tok)
-
           t.each { |s, previous_start|
             if previous_start.nil?
               # In the simple case of a "default" param regex do this fast-path and add all
               # next states.
-              if token_matches_default_component && std_state = @stdparam_states[s]
+              if token_matches_default && std_state = @stdparam_states[s]
                 next_states << [std_state, nil].freeze
               end
 
               # When we have a literal string, we can just pull the next state
               if states = @string_states[s]
-                next_states << [states[tok], nil].freeze unless states[tok].nil?
+                next_states << [states[token], nil].freeze unless states[token].nil?
               end
             end
 
@@ -80,7 +77,7 @@ def move(t, full_string, start_index, end_index)
                 previous_start
               end
 
-              slice_length = end_index - slice_start
+              slice_length = start_index + token.length - slice_start
               curr_slice = full_string.slice(slice_start, slice_length)
 
               states.each { |re, v|

actionpack/test/journey/gtg/builder_test.rb

@@ -8,13 +8,13 @@ module GTG
       class TestBuilder < ActiveSupport::TestCase
         def test_following_states_multi
           table = tt ["a|a"]
-          assert_equal 1, table.move([[0, nil]], "a", 0, 1).length
+          assert_equal 1, table.move([[0, nil]], "a", "a", 0, true).length
         end
 
         def test_following_states_multi_regexp
           table = tt [":a|b"]
-          assert_equal 1, table.move([[0, nil]], "fooo", 0, 4).length
-          assert_equal 2, table.move([[0, nil]], "b", 0, 1).length
+          assert_equal 1, table.move([[0, nil]], "fooo", "fooo", 0, true).length
+          assert_equal 2, table.move([[0, nil]], "b", "b", 0, true).length
         end
 
         def test_multi_path
@@ -26,7 +26,7 @@ def test_multi_path
             [2, "/"],
             [1, "c"],
           ].inject([[0, nil]]) { |state, (exp, sym)|
-            new = table.move(state, sym, 0, sym.length)
+            new = table.move(state, sym, sym, 0, sym != "/")
             assert_equal exp, new.length
             new
           }