From 4cd9223a9a7e7ec29d1597521dbe3399b06e4d18 Mon Sep 17 00:00:00 2001
From: Michael Herold <opensource@michaeljherold.com>
Date: Sun, 26 Feb 2023 15:03:17 -0600
Subject: [PATCH] Make OutputBuffer more performant for 3.2+ YJIT

This change ports Jean Boussier's Rails change over to Bridgetown with a
few tweaks.

1. Using `instance_of?` against the constant is faster than the
   alternative `self.class == other.class` construct
2. Linear, comparable logic for `<<`
3. An expanded set of delegated methods to include `#empty?`, `#encode`,
   `#lines`, `#reverse`, `#strip`, and `#valid_encoding?` because these
   are all called in the test suite.

In the current test suite, this is a count of how many times each method
is called:

2794 empty?
  54 encode
  54 encoding
 381 lines
 127 reverse
 127 strip
  54 valid_encoding?

It's unclear to me which, if any, of these should be public API so I
kept all of the delegated methods as well as the ones Jean picked for
Rails.
---
 .../converters/erb_templates.rb               | 57 +++++++++++++++++--
 .../test/bridgetown/test_output_buffer.rb     | 41 +++++++++++++
 2 files changed, 92 insertions(+), 6 deletions(-)
 create mode 100644 bridgetown-core/test/bridgetown/test_output_buffer.rb

diff --git a/bridgetown-core/lib/bridgetown-core/converters/erb_templates.rb b/bridgetown-core/lib/bridgetown-core/converters/erb_templates.rb
index 552fc9efe..40248ba8f 100644
--- a/bridgetown-core/lib/bridgetown-core/converters/erb_templates.rb
+++ b/bridgetown-core/lib/bridgetown-core/converters/erb_templates.rb
@@ -3,26 +3,71 @@
 require "tilt/erubi"
 
 module Bridgetown
-  class OutputBuffer < ActiveSupport::SafeBuffer
-    def initialize(*)
-      super
-      encode!
+  class OutputBuffer
+    def initialize(buffer = "")
+      @buffer = String.new(buffer)
+      @buffer.encode!
     end
 
+    def initialize_copy(other)
+      @buffer = other.to_str
+    end
+
+    delegate(
+      :blank?,
+      :empty?,
+      :encode,
+      :encode!,
+      :encoding,
+      :force_encoding,
+      :length,
+      :lines,
+      :reverse,
+      :strip,
+      :valid_encoding?,
+      to: :@buffer
+    )
+
     def <<(value)
       return self if value.nil?
 
-      super(value.to_s)
+      value = value.to_s
+      value = CGI.escapeHTML(value) unless value.html_safe?
+
+      @buffer << value
+
+      self
     end
     alias_method :append=, :<<
 
+    def ==(other)
+      other.instance_of?(OutputBuffer) &&
+        @buffer == other.to_str
+    end
+
+    def html_safe?
+      true
+    end
+
+    def safe_concat(value)
+      @buffer << value
+      self
+    end
+    alias_method :safe_append=, :safe_concat
+
     def safe_expr_append=(val)
       return self if val.nil? # rubocop:disable Lint/ReturnInVoidContext
 
       safe_concat val.to_s
     end
 
-    alias_method :safe_append=, :safe_concat
+    def to_s
+      @buffer.html_safe
+    end
+
+    def to_str
+      @buffer.dup
+    end
   end
 
   class ERBEngine < Erubi::Engine
diff --git a/bridgetown-core/test/bridgetown/test_output_buffer.rb b/bridgetown-core/test/bridgetown/test_output_buffer.rb
new file mode 100644
index 000000000..dbc3bde4b
--- /dev/null
+++ b/bridgetown-core/test/bridgetown/test_output_buffer.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require "helper"
+
+module Bridgetown
+  class OutputBufferTest < BridgetownUnitTest
+    def setup
+      super
+      @buffer = Bridgetown::OutputBuffer.new
+    end
+
+    should "be able to be duped" do
+      @buffer << "Hello"
+      copy = @buffer.dup
+      copy << " world!"
+
+      assert_equal "Hello", @buffer.to_s
+      assert_equal "Hello world!", copy.to_s
+    end
+
+    context "#<<" do
+      should "maintain HTML safety" do
+        @buffer << "<p>Nothing bad to see here.</p>"
+
+        assert_predicate @buffer, :html_safe?
+        assert_predicate @buffer.to_s, :html_safe?
+        assert_equal "&lt;p&gt;Nothing bad to see here.&lt;/p&gt;", @buffer.to_s
+      end
+    end
+
+    context "#safe_append=" do
+      should "bypass HTML safety" do
+        @buffer.safe_append = "<p>Nothing bad to see here.</p>"
+
+        assert_predicate @buffer, :html_safe?
+        assert_predicate @buffer.to_s, :html_safe?
+        assert_equal "<p>Nothing bad to see here.</p>", @buffer.to_s
+      end
+    end
+  end
+end