Add rubygem (#2)

* Adding ruby gem

* Add Instance getter and test

* Typo

* Update comments

* Update README

* Add resize method

* Update comments

* Add header method to patch python lib capability

* Add 4 bytes to account for removing header

wasm-thumbnail-rb/.gitignore

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+/.bundle/
+/.yardoc
+/_yardoc/
+/coverage/
+/doc/
+/pkg/
+/spec/reports/
+/tmp/

wasm-thumbnail-rb/.rubocop.yml

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+AllCops:
+  TargetRubyVersion: 2.7
+
+Style/StringLiterals:
+  Enabled: true
+  EnforcedStyle: double_quotes
+
+Style/StringLiteralsInInterpolation:
+  Enabled: true
+  EnforcedStyle: double_quotes
+
+Layout/LineLength:
+  Max: 120

wasm-thumbnail-rb/Gemfile

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+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+# Specify your gem's dependencies in wasm-thumbnail-rb.gemspec
+gemspec
+
+gem "rake", "~> 13.0"
+
+gem "minitest", "~> 5.0"
+
+gem "rubocop", "~> 1.7"

wasm-thumbnail-rb/README.md

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+# Wasm::Thumbnail::Rb
+
+## Installation
+
+Note this gem has not been released to rubygems. It may in the future but for now it is intended to be referenced via git.
+
+Add this line to your application's Gemfile:
+
+```ruby
+gem 'wasm-thumbnail-rb', git: 'gitlocationofgem'
+```
+
+And then execute:
+
+    $ bundle install
+
+## Usage
+
+See `rb_test.rb` for an example of usage.
+
+## Development
+
+After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
+
+To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and the created tag, and push the `.gem` file to [rubygems.org](https://rubygems.org).
+
+## Contributing
+
+Bug reports and pull requests are welcome on GitHub at https://github.com/brave-intl/wasm-thumbnail-rb.

wasm-thumbnail-rb/Rakefile

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+# frozen_string_literal: true
+
+require "bundler/gem_tasks"
+require "rake/testtask"
+
+Rake::TestTask.new(:test) do |t|
+  t.libs << "test"
+  t.libs << "lib"
+  t.test_files = FileList["test/**/*_test.rb"]
+end
+
+require "rubocop/rake_task"
+
+RuboCop::RakeTask.new
+
+task default: %i[test rubocop]

wasm-thumbnail-rb/bin/console

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+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require "bundler/setup"
+require "wasm/thumbnail/rb"
+
+# You can add fixtures and/or initialization code here to make experimenting
+# with your gem easier. You can also use a different console, if you like.
+
+# (If you use this, don't forget to add pry to your Gemfile!)
+# require "pry"
+# Pry.start
+
+require "irb"
+IRB.start(__FILE__)

wasm-thumbnail-rb/bin/setup

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+#!/usr/bin/env bash
+set -euo pipefail
+IFS=$'\n\t'
+set -vx
+
+bundle install
+
+# Do any other automated setup that you need to do here

wasm-thumbnail-rb/lib/wasm/thumbnail/rb.rb

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+# frozen_string_literal: true
+
+require_relative "rb/version"
+require "wasmer"
+module Wasm
+  module Thumbnail
+    # As opposed to the PY implementation
+    module Rb
+      class Error < StandardError; end
+
+      # Now the module is compiled, we can instantiate it. Doing so outside the method where used results in errors.
+      def self.register_panic(_msg_ptr = nil, _msg_len = nil, _file_ptr = nil, _file_len = nil, _line = nil, _column = nil)
+        puts("WASM panicked")
+      end
+
+      WASMStore = Wasmer::Store.new
+      WASMImportObject = Wasmer::ImportObject.new
+      WASMImportObject.register(
+        "env",
+        register_panic: Wasmer::Function.new(
+          WASMStore,
+          :register_panic,
+          Wasmer::FunctionType.new([Wasmer::Type::I32,
+                                    Wasmer::Type::I32,
+                                    Wasmer::Type::I32,
+                                    Wasmer::Type::I32,
+                                    Wasmer::Type::I32,
+                                    Wasmer::Type::I32], [])
+        )
+      )
+
+      def self.resize_and_pad_with_header(file_bytes:, width:, height:, size:)
+        # Let's compile the module to be able to execute it!
+        wasm_instance = Wasm::Thumbnail::Rb::GetWasmInstance.call
+
+        # This tells us how much space we'll need to put our image in the WASM env
+        image_length = file_bytes.length
+        input_pointer = wasm_instance.exports.allocate.call(image_length)
+        # Get a pointer on the allocated memory so we can write to it
+        memory = wasm_instance.exports.memory.uint8_view input_pointer
+
+        # Put the image to resize in the allocated space
+        (0..image_length - 1).each do |nth|
+          memory[nth] = file_bytes[nth]
+        end
+
+        # Do the actual resize and pad
+        # Note that this writes to a portion of memory the new JPEG file, but right pads the rest of the space
+        # we gave it with 0.
+        begin
+          output_pointer = wasm_instance.exports.resize_and_pad.call(input_pointer,
+                                                                     image_length,
+                                                                     width,
+                                                                     height,
+                                                                     size)
+        rescue RuntimeError
+          raise "Error processing the image."
+        end
+        # Get a pointer to the result
+        memory = wasm_instance.exports.memory.uint8_view output_pointer
+
+        # Only take the buffer that we told the rust function we needed. The resize function
+        # makes a smaller image than the buffer we said, and then pads out the rest.
+        bytes = memory.to_a.take(size)
+
+        # Deallocate
+        wasm_instance.exports.deallocate.call(input_pointer, image_length)
+        wasm_instance.exports.deallocate.call(output_pointer, bytes.length)
+
+        bytes
+      end
+
+      def self.resize_and_pad(file_bytes:, width:, height:, size:)
+        bytes = resize_and_pad_with_header(file_bytes: file_bytes, width: width, height: height, size: size + 4)
+
+        # The first 4 bytes are a header until the image. The actual image probably ends well before
+        # the whole buffer, but we keep the junk data on the end to make all the images the same size
+        # for privacy concerns.
+        bytes[4..].pack("C*")
+      end
+
+      # Return an instance so you don't have to constantly compile
+      class GetWasmInstance
+        def self.call
+          # Let's compile the module to be able to execute it!
+          Wasmer::Instance.new(
+            Wasmer::Module.new(WASMStore, IO.read("#{__dir__}/rb/data/wasm_thumbnail.wasm", mode: "rb")),
+            WASMImportObject
+          )
+        end
+      end
+    end
+  end
+end

wasm-thumbnail-rb/lib/wasm/thumbnail/rb/version.rb

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+# frozen_string_literal: true
+
+module Wasm
+  module Thumbnail
+    module Rb
+      VERSION = "0.1.0"
+    end
+  end
+end

wasm-thumbnail-rb/test/test_helper.rb

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+# frozen_string_literal: true
+
+$LOAD_PATH.unshift File.expand_path("../lib", __dir__)
+require "wasm/thumbnail/rb"
+
+require "minitest/autorun"

wasm-thumbnail-rb/test/wasm/thumbnail/rb_test.rb

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+# frozen_string_literal: true
+
+require "test_helper"
+
+class Wasm::Thumbnail::RbTest < Minitest::Test
+  def test_that_it_has_a_version_number
+    refute_nil ::Wasm::Thumbnail::Rb::VERSION
+  end
+
+  def test_it_does_something_useful
+    file_bytes = File.binread("#{__dir__}/brave.png").unpack("C*")
+    image = Wasm::Thumbnail::Rb.resize_and_pad(file_bytes: file_bytes,
+                                               width: 100,
+                                               height: 200,
+                                               size: 250_000)
+    puts "Image resized and padded to size #{image.length}"
+  end
+end

wasm-thumbnail-rb/wasm-thumbnail-rb.gemspec

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+# frozen_string_literal: true
+
+require_relative "lib/wasm/thumbnail/rb/version"
+
+Gem::Specification.new do |spec|
+  spec.name          = "wasm-thumbnail-rb"
+  spec.version       = Wasm::Thumbnail::Rb::VERSION
+  spec.authors       = ["Tyler Smart"]
+  spec.email         = ["[email protected]"]
+  spec.licenses      = ["MPL-2.0"]
+  spec.summary       = "WASM based thumbnail library"
+  spec.homepage      = "https://github.com/brave-intl/wasm-thumbnail"
+  spec.required_ruby_version = Gem::Requirement.new(">= 2.7.0")
+
+  spec.metadata["homepage_uri"] = spec.homepage
+  spec.metadata["source_code_uri"] = "https://github.com/brave-intl/wasm-thumbnail"
+
+  # Specify which files should be added to the gem when it is released.
+  # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
+  spec.files = Dir.chdir(File.expand_path(__dir__)) do
+    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{\A(?:test|spec|features)/}) }
+  end
+  spec.bindir        = "exe"
+  spec.executables   = spec.files.grep(%r{\Aexe/}) { |f| File.basename(f) }
+  spec.require_paths = ["lib"]
+
+  spec.add_dependency "wasmer", "~> 1.0"
+end