don't create string scanner for liquid tag

Gemfile

@@ -28,3 +28,5 @@ group :test do
     gem 'liquid-c', github: 'Shopify/liquid-c', ref: 'main'
   end
 end
+
+gem "strscan", ">= 3.1"

Rakefile

@@ -73,7 +73,7 @@ end
 
 namespace :benchmark do
   desc "Run the liquid benchmark with lax parsing"
-  task :run do
+  task :lax do
     ruby "./performance/benchmark.rb lax"
   end
 
@@ -82,6 +82,9 @@ namespace :benchmark do
     ruby "./performance/benchmark.rb strict"
   end
 
+  desc "Run the liquid benchmark with both lax and strict parsing"
+  task run: [:lax, :strict]
+
   desc "Run unit benchmarks"
   task :unit do
     Dir["./performance/unit/*_benchmark.rb"].each do |file|

lib/liquid/lexer.rb

@@ -92,6 +92,7 @@ module Liquid
     SINGLE_COMPARISON_TOKENS = [].tap do |table|
       table["<".ord] = COMPARISON_LESS_THAN
       table[">".ord] = COMPARISON_GREATER_THAN
+      table.freeze
     end
 
     TWO_CHARS_COMPARISON_JUMP_TABLE = [].tap do |table|
@@ -103,18 +104,17 @@ module Liquid
         sub_table["=".ord] = COMPARISION_NOT_EQUAL
         sub_table.freeze
       end
+      table.freeze
     end
 
     COMPARISON_JUMP_TABLE = [].tap do |table|
       table["<".ord] = [].tap do |sub_table|
         sub_table["=".ord] = COMPARISON_LESS_THAN_OR_EQUAL
         sub_table[">".ord] = COMPARISON_NOT_EQUAL_ALT
-        RUBY_WHITESPACE.each { |c| sub_table[c.ord] = COMPARISON_LESS_THAN }
         sub_table.freeze
       end
       table[">".ord] = [].tap do |sub_table|
         sub_table["=".ord] = COMPARISON_GREATER_THAN_OR_EQUAL
-        RUBY_WHITESPACE.each { |c| sub_table[c.ord] = COMPARISON_GREATER_THAN }
         sub_table.freeze
       end
       table.freeze
@@ -233,5 +233,6 @@ module Liquid
     end
   end
 
+  # Remove this once we can depend on strscan >= 3.1.1
   Lexer = StringScanner.instance_methods.include?(:scan_byte) ? Lexer2 : Lexer1
 end

lib/liquid/tokenizer.rb

@@ -1,7 +1,9 @@
 # frozen_string_literal: true
 
+require "strscan"
+
 module Liquid
-  class Tokenizer
+  class Tokenizer1
     attr_reader :line_number, :for_liquid_tag
 
     def initialize(source, line_numbers = false, line_number: nil, for_liquid_tag: false)
@@ -42,4 +44,147 @@ module Liquid
       tokens
     end
   end
+
+  class Tokenizer2
+    attr_reader :line_number, :for_liquid_tag
+
+    TAG_END = /%\}/
+    TAG_OR_VARIABLE_START = /\{[\{\%]/
+    NEWLINE = /\n/
+
+    OPEN_CURLEY = "{".ord
+    CLOSE_CURLEY = "}".ord
+    PERCENTAGE = "%".ord
+
+    def initialize(source, line_numbers = false, line_number: nil, for_liquid_tag: false)
+      @line_number    = line_number || (line_numbers ? 1 : nil)
+      @for_liquid_tag = for_liquid_tag
+      @source         = source
+      @offset         = 0
+      @tokens         = []
+      tokenize
+    end
+
+    def shift
+      token = @tokens[@offset]
+
+      return unless token
+
+      @offset += 1
+
+      if @line_number
+        @line_number += @for_liquid_tag ? 1 : token.count("\n")
+      end
+
+      token
+    end
+
+    private
+
+    def tokenize
+      if @for_liquid_tag
+        @tokens = @source.split("\n")
+      else
+        @ss = StringScanner.new(@source)
+        @tokens << shift_normal until @ss.eos?
+      end
+
+      @ss = nil
+      @source = nil
+    end
+
+    def shift_normal
+      token = next_token
+
+      return unless token
+
+      token
+    end
+
+    def next_token
+      # possible states: :text, :tag, :variable
+      byte_a = @ss.peek_byte
+
+      if byte_a == OPEN_CURLEY
+        @ss.scan_byte
+
+        byte_b = @ss.peek_byte
+
+        if byte_b == PERCENTAGE
+          @ss.scan_byte
+          return next_tag_token
+        elsif byte_b == OPEN_CURLEY
+          @ss.scan_byte
+          return next_variable_token
+        end
+
+        @ss.pos -= 1
+      end
+
+      next_text_token
+    end
+
+    def next_text_token
+      start = @ss.pos
+
+      unless @ss.skip_until(TAG_OR_VARIABLE_START)
+        token = @ss.rest
+        @ss.terminate
+        return token
+      end
+
+      pos = @ss.pos -= 2
+      @source.byteslice(start, pos - start)
+    end
+
+    def next_variable_token
+      start = @ss.pos - 2
+
+      byte_a = byte_b = @ss.scan_byte
+
+      while byte_b
+        byte_a = @ss.scan_byte while byte_a && (byte_a != CLOSE_CURLEY && byte_a != OPEN_CURLEY)
+
+        break unless byte_a
+
+        if @ss.eos?
+          return byte_a == CLOSE_CURLEY ? @source.byteslice(start, @ss.pos - start) : "{{"
+        end
+
+        byte_b = @ss.scan_byte
+
+        if byte_a == CLOSE_CURLEY
+          if byte_b == CLOSE_CURLEY
+            return @source.byteslice(start, @ss.pos - start)
+          elsif byte_b != CLOSE_CURLEY
+            @ss.pos -= 1
+            return @source.byteslice(start, @ss.pos - start)
+          end
+        elsif byte_a == OPEN_CURLEY && byte_b == PERCENTAGE
+          return next_tag_token_with_start(start)
+        end
+
+        byte_a = byte_b
+      end
+
+      "{{"
+    end
+
+    def next_tag_token
+      start = @ss.pos - 2
+      if (len = @ss.skip_until(TAG_END))
+        @source.byteslice(start, len + 2)
+      else
+        "{%"
+      end
+    end
+
+    def next_tag_token_with_start(start)
+      @ss.skip_until(TAG_END)
+      @source.byteslice(start, @ss.pos - start)
+    end
+  end
+
+  # Remove this once we can depend on strscan >= 3.1.1
+  Tokenizer = StringScanner.instance_methods.include?(:scan_byte) ? Tokenizer2 : Tokenizer1
 end

performance/benchmark.rb

@@ -8,14 +8,17 @@ Liquid::Template.error_mode = ARGV.first.to_sym if ARGV.first
 profiler = ThemeRunner.new
 
 Benchmark.ips do |x|
-  x.time   = 10
+  x.time   = 20
-  x.warmup = 5
+  x.warmup = 10
 
   puts
   puts "Running benchmark for #{x.time} seconds (with #{x.warmup} seconds warmup)."
   puts
 
-  x.report("parse:") { profiler.compile }
+  phase = ENV["PHASE"] || "all"
-  x.report("render:") { profiler.render }
+
-  x.report("parse & render:") { profiler.run }
+  x.report("tokenize:") { profiler.tokenize } if phase == "all" || phase == "tokenize"
+  x.report("parse:") { profiler.compile } if phase == "all" || phase == "parse"
+  x.report("render:") { profiler.render } if phase == "all" || phase == "render"
+  x.report("parse & render:") { profiler.run } if phase == "all" || phase == "run"
 end

performance/theme_runner.rb

@@ -48,6 +48,14 @@ class ThemeRunner
     end
   end
 
+  # `tokenize` will just test the tokenizen portion of liquid without any templates
+  def tokenize
+    @tests.each do |test_hash|
+      tokenizer = Liquid::Tokenizer.new(test_hash[:liquid], true)
+      while tokenizer.shift; end
+    end
+  end
+
   # `run` is called to benchmark rendering and compiling at the same time
   def run
     each_test do |liquid, layout, assigns, page_template, template_name|

test/integration/parsing_quirks_test.rb

@@ -134,6 +134,14 @@ class ParsingQuirksTest < Minitest::Test
 
   def test_incomplete_expression
     with_error_mode(:lax) do
+      assert_template_result("false", "{{ false - }}")
+      assert_template_result("false", "{{ false > }}")
+      assert_template_result("false", "{{ false < }}")
+      assert_template_result("false", "{{ false = }}")
+      assert_template_result("false", "{{ false ! }}")
+      assert_template_result("false", "{{ false 1 }}")
+      assert_template_result("false", "{{ false a }}")
+
       assert_template_result("false", "{% liquid assign foo = false -\n%}{{ foo }}")
       assert_template_result("false", "{% liquid assign foo = false >\n%}{{ foo }}")
       assert_template_result("false", "{% liquid assign foo = false <\n%}{{ foo }}")

test/integration/tags/raw_tag_test.rb

@@ -16,6 +16,7 @@ class RawTagTest < Minitest::Test
     assert_template_result('>{{ test }}<', '> {%- raw -%}{{ test }}{%- endraw -%} <')
     assert_template_result("> inner  <", "> {%- raw -%} inner {%- endraw %} <")
     assert_template_result("> inner <", "> {%- raw -%} inner {%- endraw -%} <")
+    assert_template_result("{Hello}", "{% raw %}{{% endraw %}Hello{% raw %}}{% endraw %}")
   end
 
   def test_open_tag_in_raw

test/test_helper.rb

@@ -13,7 +13,7 @@ if (env_mode = ENV['LIQUID_PARSER_MODE'])
   puts "-- #{env_mode.upcase} ERROR MODE"
   mode = env_mode.to_sym
 end
-Liquid::Template.error_mode = mode
+Liquid::Environment.default.error_mode = mode
 
 if ENV['LIQUID_C'] == '1'
   puts "-- LIQUID C"

test/unit/tokenizer_unit_test.rb

@@ -6,6 +6,7 @@ class TokenizerTest < Minitest::Test
   def test_tokenize_strings
     assert_equal([' '], tokenize(' '))
     assert_equal(['hello world'], tokenize('hello world'))
+    assert_equal(['{}'], tokenize('{}'))
   end
 
   def test_tokenize_variables
@@ -30,6 +31,19 @@ class TokenizerTest < Minitest::Test
     assert_equal([1, 1, 3], tokenize_line_numbers(" {{\n funk \n}} "))
   end
 
+  def test_incomplete_curly_braces
+    assert_equal(["{{.}", " "], tokenize('{{.} '))
+    assert_equal(["{{}", "%}"], tokenize('{{}%}'))
+    assert_equal(["{{}}", "}"], tokenize('{{}}}'))
+  end
+
+  def test_unmatching_start_and_end
+    assert_equal(["{{%}"], tokenize('{{%}'))
+    assert_equal(["{{%%%}}"], tokenize('{{%%%}}'))
+    assert_equal(["{%", "}}"], tokenize('{%}}'))
+    assert_equal(["{%%}", "}"], tokenize('{%%}}'))
+  end
+
   private
 
   def new_tokenizer(source, parse_context: Liquid::ParseContext.new, start_line_number: nil)