Profile liquid rendering

Add a simple profiling system to liquid rendering. Each
liquid tag ({{ }} and {% %}) is processed through this profiling,
keeping track of the partial name (in the case of {% include %}), line
number, and the time it took to render the tag. In the case of {%
include %}, the profiler keeps track of the name of the partial and
properly links back tag rendering to the partial and line number for
easy lookup and dive down. With this, it's now possible to track down
exactly how long each tag takes to render.

These hooks get installed and uninstalled on an as-need basis so by
default there is no impact on the overall liquid execution speed.

test/integration/render_profiling_test.rb

@@ -0,0 +1,142 @@
+require 'test_helper'
+
+class RenderProfilingTest < Minitest::Test
+  include Liquid
+
+  class ProfilingFileSystem
+    def read_template_file(template_path, context)
+      "Rendering template {% assign template_name = '#{template_path}'%}\n{{ template_name }}"
+    end
+  end
+
+  def setup
+    Liquid::Template.file_system = ProfilingFileSystem.new
+  end
+
+  def test_template_allows_flagging_profiling
+    t = Template.parse("{{ 'a string' | upcase }}")
+    t.render!
+
+    assert_nil t.profiler
+  end
+
+  def test_parse_makes_available_simple_profiling
+    t = Template.parse("{{ 'a string' | upcase }}", :profile => true)
+    t.render!
+
+    assert_equal 1, t.profiler.length
+
+    node = t.profiler[0]
+    assert_equal " 'a string' | upcase ", node.code
+  end
+
+  def test_render_ignores_raw_strings_when_profiling
+    t = Template.parse("This is raw string\nstuff\nNewline", :profile => true)
+    t.render!
+
+    assert_equal 0, t.profiler.length
+  end
+
+  def test_profiling_includes_line_numbers_of_liquid_nodes
+    t = Template.parse("{{ 'a string' | upcase }}\n{% increment test %}", :profile => true)
+    t.render!
+    assert_equal 2, t.profiler.length
+
+    # {{ 'a string' | upcase }}
+    assert_equal 1, t.profiler[0].line_number
+    # {{ increment test }}
+    assert_equal 2, t.profiler[1].line_number
+  end
+
+  def test_profiling_times_the_rendering_of_tokens
+    t = Template.parse("{% include 'a_template' %}", :profile => true)
+    t.render!
+
+    node = t.profiler[0]
+    refute_nil node.render_time
+  end
+
+  def test_profiling_times_the_entire_render
+    t = Template.parse("{% include 'a_template' %}", :profile => true)
+    t.render!
+
+    assert t.profiler.total_render_time > 0, "Total render time was not calculated"
+  end
+
+  def test_profiling_uses_include_to_mark_children
+    t = Template.parse("{{ 'a string' | upcase }}\n{% include 'a_template' %}", :profile => true)
+    t.render!
+
+    include_node = t.profiler[1]
+    assert_equal 2, include_node.children.length
+  end
+
+  def test_profiling_marks_children_with_the_name_of_included_partial
+    t = Template.parse("{{ 'a string' | upcase }}\n{% include 'a_template' %}", :profile => true)
+    t.render!
+
+    include_node = t.profiler[1]
+    include_node.children.each do |child|
+      assert_equal "'a_template'", child.partial
+    end
+  end
+
+  def test_profiling_supports_multiple_templates
+    t = Template.parse("{{ 'a string' | upcase }}\n{% include 'a_template' %}\n{% include 'b_template' %}", :profile => true)
+    t.render!
+
+    a_template = t.profiler[1]
+    a_template.children.each do |child|
+      assert_equal "'a_template'", child.partial
+    end
+
+    b_template = t.profiler[2]
+    b_template.children.each do |child|
+      assert_equal "'b_template'", child.partial
+    end
+  end
+
+  def test_profiling_supports_rendering_the_same_partial_multiple_times
+    t = Template.parse("{{ 'a string' | upcase }}\n{% include 'a_template' %}\n{% include 'a_template' %}", :profile => true)
+    t.render!
+
+    a_template1 = t.profiler[1]
+    a_template1.children.each do |child|
+      assert_equal "'a_template'", child.partial
+    end
+
+    a_template2 = t.profiler[2]
+    a_template2.children.each do |child|
+      assert_equal "'a_template'", child.partial
+    end
+  end
+
+  def test_can_iterate_over_each_profiling_entry
+    t = Template.parse("{{ 'a string' | upcase }}\n{% increment test %}", :profile => true)
+    t.render!
+
+    timing_count = 0
+    t.profiler.each do |timing|
+      timing_count += 1
+    end
+
+    assert_equal 2, timing_count
+  end
+
+  def test_profiling_marks_children_of_if_blocks
+    t = Template.parse("{% if true %} {% increment test %} {{ test }} {% endif %}", :profile => true)
+    t.render!
+
+    assert_equal 1, t.profiler.length
+    assert_equal 2, t.profiler[0].children.length
+  end
+
+  def test_profiling_marks_children_of_for_blocks
+    t = Template.parse("{% for item in collection %} {{ item }} {% endfor %}", :profile => true)
+    t.render!({"collection" => ["one", "two"]})
+
+    assert_equal 1, t.profiler.length
+    # Will profile each invocation of the for block
+    assert_equal 2, t.profiler[0].children.length
+  end
+end

test/unit/tag_unit_test.rb

@@ -8,4 +8,9 @@ class TagUnitTest < Minitest::Test
     assert_equal 'liquid::tag', tag.name
     assert_equal '', tag.render(Context.new)
   end
+
+  def test_return_raw_text_of_tag
+    tag = Tag.parse("long_tag", "param1, param2, param3", [], {})
+    assert_equal("long_tag param1, param2, param3", tag.raw)
+  end
 end

test/unit/tokenizer_unit_test.rb

@@ -21,6 +21,15 @@ class TokenizerTest < Minitest::Test
     assert_equal ['  ', '{% comment %}', ' ', '{% endcomment %}', ' '], tokenize("  {% comment %} {% endcomment %} ")
   end
 
+  def test_calculate_line_numbers_per_token_with_profiling
+    template = Liquid::Template.parse("", :profile => true)
+
+    assert_equal [1],       template.send(:tokenize, "{{funk}}").map(&:line_number)
+    assert_equal [1, 1, 1], template.send(:tokenize, " {{funk}} ").map(&:line_number)
+    assert_equal [1, 2, 2], template.send(:tokenize, "\n{{funk}}\n").map(&:line_number)
+    assert_equal [1, 1, 3], template.send(:tokenize, " {{\n funk \n}} ").map(&:line_number)
+  end
+
   private
 
   def tokenize(source)

test/unit/variable_unit_test.rb

@@ -133,4 +133,9 @@ class VariableUnitTest < Minitest::Test
       end
     end
   end
+
+  def test_output_raw_source_of_variable
+    var = Variable.new(%! name_of_variable | upcase !)
+    assert_equal " name_of_variable | upcase ", var.raw
+  end
 end