Implement sass --embedded in pure JS mode

[ntkme]

Closes #2325.

sass/embedded-host-node#344

Implementation

The actual isolate dispatcher and compilation dispatcher are nearly unchanged. However, I had to replace isolate with worker communication, and mock tons of small things that do not work on node.

Testing

• All Dart embedded tests are passing. - GitHub CI has been updated to run these in this PR.
• All JS API tests are passing. - GitHub CI has been updated to run these in this PR.
• All Ruby API tests are passing.

[ntkme]

Here are some benchmark results on 1.80.5 native binary vs pkg-npm-release (node v22.9.0).

I tested three cases. All of them on a single persisted compiler, lines that marked with /MT means multi-threaded (10 threads).

1. Minimal Sass Input - compile a {b: c} 10000 times.
2. High Round Trips - invoke host function 10 times per compilation, and run 1000 compilations.
3. Bootstrap - compile bootstrap 50 times.

On single-threaded test Dart is much faster than pure JS, especially in the compute heavy bootstrap test. However, in nearly all multi-threaded test, pure JS is not far from Dart, which is actually great.

sass-embedded	1.80.5	(Embedded Host)	[Ruby]
dart-sass	1.80.5	(Sass Compiler)	[JavaScript]
--- Minimal Sass Input ---
                       user     system      total        real
sass-embedded      0.304688   0.081796   0.386484 (  2.195485)
sass-embedded/MT   0.546339   0.260653   0.806992 (  1.260589)
--- High Round Trips ---
                       user     system      total        real
sass-embedded      0.268202   0.084800   0.353002 (  2.135437)
sass-embedded/MT   0.316647   0.207332   0.523979 (  0.558180)
--- Bootstrap ---
                       user     system      total        real
sass-embedded      0.013900   0.006100   0.020000 ( 27.595710)
sass-embedded/MT   0.023358   0.012144   0.035502 (  3.378303)

sass-embedded	1.80.5	(Embedded Host)	[Ruby]
dart-sass	1.80.5	(Sass Compiler)	[Dart]
--- Minimal Sass Input ---
                       user     system      total        real
sass-embedded      0.255831   0.066576   0.322407 (  1.207566)
sass-embedded/MT   0.323200   0.218337   0.541537 (  0.578477)
--- High Round Trips ---
                       user     system      total        real
sass-embedded      0.197848   0.069268   0.267116 (  0.840963)
sass-embedded/MT   0.256294   0.226492   0.482786 (  0.521811)
--- Bootstrap ---
                       user     system      total        real
sass-embedded      0.013402   0.005420   0.018822 (  7.295685)
sass-embedded/MT   0.015503   0.008968   0.024471 (  2.538047)

Benchmark code

require 'benchmark'
require 'sass-embedded'

puts Sass.info

BOOTSTRAP = Gem::Specification.find_by_name('bootstrap').gem_dir + '/assets/stylesheets/_bootstrap.scss'

def run(n:, thread: 10, use_thread: false)
  if use_thread
    queue = Queue.new
    n.times do
      queue << nil
    end
    list = []
    thread.times do
      list << Thread.new do
        loop do
          queue.pop(true)
          yield
        rescue ThreadError
          break
        end
      end
    end
    list.each(&:join)
    queue.close
  else
    n.times do
      yield
    end
  end
end

def sass_embedded_minimal(use_thread: false)
  run(n: 10000, use_thread:) do
    Sass.compile_string('a {b: c}', style: :compressed, logger: Sass::Logger.silent).css
  end
end

def sass_embedded_round_trips(use_thread: false)
  run(n: 1000, use_thread:) do
    Sass.compile_string('@for $i from 1 through 10 { a:nth-child(#{$i}) { b: foo(); } }', functions: { 'foo()' => ->(_) { Sass::Value::String.new('test') } }, style: :compressed, logger: Sass::Logger.silent).css
  end
end

def sass_embedded_bootstrap(use_thread: false)
  run(n: 50, use_thread:) do
    Sass.compile(BOOTSTRAP, style: :compressed, logger: Sass::Logger.silent).css
  end
end

puts '--- Minimal Sass Input ---'
Benchmark.bm(16) do |x|
  GC.start

  x.report('sass-embedded') do
    sass_embedded_minimal
  end

  GC.start

  x.report('sass-embedded/MT') do
    sass_embedded_minimal(use_thread: true)
  end
end

puts '--- High Round Trips ---'
Benchmark.bm(16) do |x|
  GC.start

  x.report('sass-embedded') do
    sass_embedded_round_trips
  end

  GC.start

  x.report('sass-embedded/MT') do
    sass_embedded_round_trips(use_thread: true)
  end
end

puts '--- Bootstrap ---'
Benchmark.bm(16) do |x|
  GC.start

  x.report('sass-embedded') do
    sass_embedded_bootstrap
  end

  GC.start

  x.report('sass-embedded/MT') do
    sass_embedded_bootstrap(use_thread: true)
  end
end

[nex3]

This PR is on my radar, it's just been a very review-heavy few weeks for me and this is unfortunately on the low end of the priority spectrum.