perf: allow concurrent flutter pub get

Author: soumyamahunt

Gemfile

@@ -4,13 +4,10 @@ source 'https://rubygems.org'
 gemspec
 
 group :development do
-  gem 'cocoapods'
-  gem 'cocoapods-plugins'
-  gem 'github_api'
-
   gem 'mocha'
   gem 'bacon'
   gem 'mocha-on-bacon'
   gem 'prettybacon'
   gem 'solargraph'
+  gem 'github_api'
 end

Gemfile.lock

@@ -3,6 +3,7 @@ PATH
   specs:
     cocoapods-embed-flutter (0.6.0)
       cocoapods
+      concurrent-ruby
       fileutils
       yaml
 
@@ -214,9 +215,7 @@ PLATFORMS
 DEPENDENCIES
   bacon
   bundler
-  cocoapods
   cocoapods-embed-flutter!
-  cocoapods-plugins
   github_api
   mocha
   mocha-on-bacon

cocoapods-embed-flutter.gemspec

@@ -27,6 +27,7 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency 'yaml'
   spec.add_runtime_dependency 'fileutils'
   spec.add_runtime_dependency 'cocoapods'
+  spec.add_runtime_dependency 'concurrent-ruby'
 
   spec.add_development_dependency 'bundler'
   spec.add_development_dependency 'rake'

example/ios_app/Gemfile.lock

@@ -3,6 +3,7 @@ PATH
   specs:
     cocoapods-embed-flutter (0.6.0)
       cocoapods
+      concurrent-ruby
       fileutils
       yaml
 

lib/cocoapods-embed-flutter/flutter/dependency.rb

@@ -27,10 +27,10 @@ class Dependency
       # @param [String, Hash] requirements
       #        the requirements for dependency as declred in `pubspec`
       #
-      # @param [Spec] parent_specification
+      # @param [Spec] parent_spec
       #        the parent specification where dependency declared
       #
-      # @param [Boolean] is_dev_dependency
+      # @param [Boolean] dev_dependency
       #        Whether the dependency only required during development
       #
       def initialize(name, requirements, parent_spec, dev_dependency = false)
@@ -48,10 +48,10 @@ def initialize(name, requirements, parent_spec, dev_dependency = false)
       # @param    [Hash] hash declared in `dependencies` or `dev_dependencies`
       #           section in `pubspec.yaml` file
       #
-      # @param    [Spec] parent_specification
+      # @param    [Spec] parent_spec
       #           the parent specification where dependency declared
       #
-      # @param    [Boolean] is_dev_dependency
+      # @param    [Boolean] dev_dependency
       #           Whether the dependency only required during development
       #
       # @return   [Array<Dependency>] dependencies from hash declared in `dependencies`
@@ -74,14 +74,29 @@ def spec
         Spec.find(name, File.expand_path(path, File.dirname(parent_spec.defined_in_file)))
       end
 
-      # Install this dependency for the parent project.
+      # Concurrently install this dependency for the parent project.
       #
-      # @return [void]
+      # @return [Concurrent::Promises::Future, Nil]
+      #         {Nil} if not a local dependency, otherwise
+      #         returns future for {#spec}'s {Spec#pub_get pub_get} task.
       #
       def install
-        spec.setup if local?
+        spec.pub_get if local?
       end
 
+      # Allows accessing top level values in
+      # {https://dart.dev/tools/pub/dependencies dependency requirements},
+      # if {#requirements} type is {Hash}, i.e. path, git etc.
+      #
+      # @param    [Symbol] m
+      #           top level key value to access, i.e. path, git etc.
+      #
+      # @return depending on accessed value type in {#requirements}.
+      #
+      # @raise [NoMethodError] if no method or custom attribute exists by
+      #        the attribute name in {#requirements} or {#requirements}
+      #        is not a {Hash}.
+      #
       def method_missing(m, *args, &block)
         if requirements.is_a?(Hash) && requirements.include?(m.to_s)
           return requirements[m.to_s]

lib/cocoapods-embed-flutter/flutter/downloader.rb

@@ -3,6 +3,9 @@
 
 module Flutter
   module Pub
+    # The Downloader modules name-spaces all the classes and methods
+    # for downloading and caching remote Flutter projects.
+    #
     module Downloader
       # Downloads a package from the given `request` to the given `target` location.
       #

lib/cocoapods-embed-flutter/flutter/external_sources.rb

@@ -41,7 +41,7 @@ def self.fetchWithNameAndOptions(name, options)
         if SOURCE_KEYS.keys.any? { |key| options.key?(key) }
           source = DownloaderSource.new(name, options, Pod::Config.instance.podfile_path)
           source.fetch(Pod::Config.instance.sandbox)
-          path = source.normalized_pupspec_path
+          path = source.normalized_pubspec_path
         elsif options.key?(:path)
           path = options[:path]
         else
@@ -137,7 +137,7 @@ def description
         # @note   If the declared path is expanded only if the represents a path
         #         relative to the file system.
         #
-        def normalized_pupspec_path(declared_path)
+        def normalized_pubspec_path(declared_path)
           Spec.find_file(name, declared_path)
         end
 
@@ -147,7 +147,7 @@ def normalized_pupspec_path(declared_path)
         # @return [String] The uri of the pubspec appending the name of the file
         #         and expanding it if necessary.
         #
-        def normalized_pupspec_path
+        def normalized_pubspec_path
           search_path = params[:path].nil? ? target : File.expand_path(params[:path], target)
           Spec.find_file(name, search_path)
         end

lib/cocoapods-embed-flutter/flutter/pubspec.rb

@@ -1,5 +1,8 @@
 require 'cocoapods-embed-flutter/flutter'
 require 'yaml'
+require 'open3'
+require 'concurrent'
+require 'cocoapods'
 
 module Flutter
   module Pub
@@ -43,7 +46,8 @@ def self.find_file(name, path)
 
         if File.basename(path) == Pub::SPEC_FILE
           return path
-        elsif Dir.exists?(File.expand_path(name, path)) && File.exists?(File.expand_path(Pub::SPEC_FILE, File.expand_path(name, path)))
+        elsif Dir.exists?(File.expand_path(name, path)) &&
+         File.exists?(File.expand_path(Pub::SPEC_FILE, File.expand_path(name, path)))
           return File.expand_path(Pub::SPEC_FILE, File.expand_path(name, path))
         elsif File.exists?(File.expand_path(Pub::SPEC_FILE, path))
           return File.expand_path(Pub::SPEC_FILE, path)
@@ -88,7 +92,7 @@ def project_path
       end
 
       # @return [String] the path to the flutter project
-      # dependencies cache file.
+      #         dependencies cache file.
       #
       def package_cache_path
         File.join(project_path, Pub::TOOL_DIR, Pub::CACHE_FILE)
@@ -101,7 +105,7 @@ def pod_helper_path
       end
 
       # @return [Array<Dependency>] the list of all the projects this
-      # specification depends upon and are included in app release.
+      #         specification depends upon and are included in app release.
       #
       def dependencies
         return [] unless @data.include?('dependencies')
@@ -123,37 +127,66 @@ def all_dependencies
         dependencies + dev_dependencies
       end
 
-      # @return [Boolean] If the flutter project for this specification
-      # has all its dependencies installed.
+      # Runs `flutter pub get` on project directory concurrently.
       #
-      def setup?
-        File.exists?(package_cache_path) && (!module? || File.exists?(pod_helper_path))
+      # @return [Concurrent::Promises::Future, Nil]
+      #         {Nil} if `pub get` running/completed, otherwise
+      #         runs `flutter pub get` task in background
+      #         and returns its future.
+      #
+      def pub_get
+        future = @@current_pubgets[self]
+        return nil if !future.nil?
+        future = Concurrent::Promises.future do
+          stdout, stderr, status = Open3.capture3('flutter pub get', :chdir => self.project_path)
+          :result
+        end
+        @@current_pubgets[self] = future
+        return Concurrent::Promises.zip(future, *all_dependencies.map(&:install).compact)
       end
 
-      # Sets up the project installing all specified dependencies.
+      # See if two {Spec} instances refer to the same pubspecs.
       #
-      # @return [void]
+      # @return [Boolean] whether or not the two {Spec} instances refer to the
+      #         same projects.
       #
-      def setup
-        return if setup?
-        pup_get
-        all_dependencies.each(&:install)
+      def ==(other)
+        self.class === other &&
+         other.defined_in_file == defined_in_file &&
+         other.instance_variable_get(:@data) == @data
       end
 
-      # Runs `flutter pub get` on project directory.
-      #
-      # @return [void]
+      # @return [Fixnum] A hash identical for equals objects.
       #
-      def pup_get
-        Dir.chdir(project_path) { |path| system('flutter pub get', exception: true) }
+      def hash
+        [defined_in_file, @data].hash
       end
 
+      alias eql? ==
+
+      # Allows accessing top level values in `pubspec.yaml`,
+      # i.e. name, description, version etc.
+      #
+      # @param    [Symbol] m
+      #           top level key value to access,
+      #           i.e. name, description etc.
+      #
+      # @return depending on accessed value type in `pubspec.yaml`.
+      #
+      # @raise [NoMethodError] if no method or custom attribute exists by
+      #        the attribute name in pubspec.
+      #
       def method_missing(m, *args, &block)
         if @data.include?(m.to_s)
           return @data[m.to_s]
         end
         super.method_missing(m, *args, &block)
       end
+
+      private
+
+      # A hash containing all `pub get` promises.
+      @@current_pubgets = {}
     end
   end
 end

lib/cocoapods-embed-flutter/src/pub.rb

@@ -112,7 +112,10 @@ module DSL
       #
       def pub(name = nil, *requirements)
         pubspec = Flutter::Pub::ExternalSources.fetchWithNameAndOptions(name, requirements)
-        pubspec.setup
+        Pod::UI.titled_section("Installing flutter dependencies for #{name}...",  :verbose_prefix => '-> ') do
+          future = pubspec.pub_get
+          future.value! if !future.nil?
+        end
         raise StandardError, "Invalid flutter module: '#{name}'." unless File.exists?(pubspec.pod_helper_path)
         install_flutter_pods_for_pubspec(pubspec)
       end