Merge pull request #3577 from pducks32/master

refactor parallel installer

3 files changed, 156 insertions, 42 deletions

diff --git a/lib/bundler/installer.rb b/lib/bundler/installer.rb
index 7365b8f27e..68fd5cad75 100644
--- a/lib/bundler/installer.rb
+++ b/lib/bundler/installer.rb
@@ -87,6 +87,7 @@ module Bundler
       # installation is just SO MUCH FASTER. so we let people opt in.
       jobs = [Bundler.settings[:jobs].to_i-1, 1].max
       if jobs > 1 && can_install_in_parallel?
+        require 'bundler/installer/parallel_installer'
         install_in_parallel jobs, options[:standalone], force
       else
         install_sequentially options[:standalone], force
@@ -277,48 +278,7 @@ module Bundler
     end
 
     def install_in_parallel(size, standalone, force = false)
-      name2spec = {}
-      remains = {}
-      enqueued = {}
-      specs.each do |spec|
-        name2spec[spec.name] = spec
-        remains[spec.name] = true
-      end
-
-      worker_pool = Worker.new size, lambda { |name, worker_num|
-        spec = name2spec[name]
-        message = install_gem_from_spec spec, standalone, worker_num, force
-        { :name => spec.name, :post_install => message }
-      }
-
-      # Keys in the remains hash represent uninstalled gems specs.
-      # We enqueue all gem specs that do not have any dependencies.
-      # Later we call this lambda again to install specs that depended on
-      # previously installed specifications. We continue until all specs
-      # are installed.
-      enqueue_remaining_specs = lambda do
-        remains.keys.each do |name|
-          next if enqueued[name]
-          spec = name2spec[name]
-          if ready_to_install?(spec, remains)
-            worker_pool.enq name
-            enqueued[name] = true
-          end
-        end
-      end
-      enqueue_remaining_specs.call
-
-      until remains.empty?
-        message = worker_pool.deq
-        remains.delete message[:name]
-        if message[:post_install]
-          Installer.post_install_messages[message[:name]] = message[:post_install]
-        end
-        enqueue_remaining_specs.call
-      end
-      message
-    ensure
-      worker_pool && worker_pool.stop
+      ParallelInstaller.call(self, specs, size, standalone, force)
     end
 
     # We only want to install a gem spec if all its dependencies are met.
diff --git a/lib/bundler/installer/parallel_installer.rb b/lib/bundler/installer/parallel_installer.rb
new file mode 100644
index 0000000000..d4a9f7c253
--- /dev/null
+++ b/lib/bundler/installer/parallel_installer.rb
@@ -0,0 +1,117 @@
+require 'bundler/worker'
+
+
+class ParallelInstaller
+
+  class SpecInstallation
+
+    attr_accessor :spec, :name, :post_install_message, :state
+    def initialize(spec)
+      @spec, @name = spec, spec.name
+      @state = :none
+      @post_install_message = ""
+    end
+
+    def installed?
+      state == :installed
+    end
+
+    def enqueued?
+      state == :enqueued
+    end
+
+    # Only true when spec in neither installed nor already enqueued
+    def ready_to_enqueue?
+      !installed? && !enqueued?
+    end
+
+    def has_post_install_message?
+      post_install_message.empty?
+    end
+
+    def ignorable_dependency?(dep)
+      dep.type == :development || dep.name == @name
+    end
+
+    # Checks installed dependencies against spec's dependencies to make
+    # sure needed dependencies have been installed.
+    def dependencies_installed?(remaining_specs)
+      installed_specs = remaining_specs.reject(&:installed?).map(&:name)
+      already_installed = lambda {|dep| installed_specs.include? dep.name }
+      dependencies.all? {|d| already_installed[d] }
+    end
+
+    # Represents only the non-development dependencies and the ones that
+    # are itself.
+    def dependencies
+      @dependencies ||= all_dependencies.reject {|dep| ignorable_dependency? dep }
+    end
+
+    # Represents all dependencies
+    def all_dependencies
+      @spec.dependencies
+    end
+  end
+
+  def self.call(*args)
+    new(*args).call
+  end
+
+  # Returns max number of threads machine can handle with a min of 1
+  def self.max_threads
+    [Bundler.settings[:jobs].to_i-1, 1].max
+  end
+
+  def initialize(installer, all_specs, size, standalone, force)
+    @installer = installer
+    @size = size
+    @standalone = standalone
+    @force = force
+    @specs = all_specs.map { |s| SpecInstallation.new(s) }
+  end
+
+  def call
+    enqueue_specs
+    process_specs until @specs.all?(&:installed?)
+  ensure
+    worker_pool && worker_pool.stop
+  end
+
+  def worker_pool
+    @worker_pool ||= Bundler::Worker.new @size, lambda { |spec_install, worker_num|
+      message = @installer.install_gem_from_spec spec_install.spec, @standalone, worker_num, @force
+      spec_install.post_install_message = message unless message.nil?
+      spec_install
+    }
+  end
+
+  # Dequeue a spec and save its post-install message anf then enqueue the
+  # remaining specs.
+  # Some specs might've had to wait til this spec was installed to be
+  # processed so the call to `enqueue_specs` is important after every
+  # dequeue.
+  def process_specs
+    spec = worker_pool.deq
+    spec.state = :installed
+    collect_post_install_message spec if spec.has_post_install_message?
+    enqueue_specs
+  end
+
+  def collect_post_install_message(spec)
+    Bundler::Installer.post_install_messages[spec.name] = spec.post_install_message
+  end
+
+  # Keys in the remains hash represent uninstalled gems specs.
+  # We enqueue all gem specs that do not have any dependencies.
+  # Later we call this lambda again to install specs that depended on
+  # previously installed specifications. We continue until all specs
+  # are installed.
+  def enqueue_specs
+    @specs.select(&:ready_to_enqueue?).each do |spec|
+      if spec.dependencies_installed? @specs
+        worker_pool.enq spec
+        spec.state = :enqueued
+      end
+    end
+  end
+end
diff --git a/spec/install/parallel/spec_installation_spec.rb b/spec/install/parallel/spec_installation_spec.rb
new file mode 100644
index 0000000000..97288fe02f
--- /dev/null
+++ b/spec/install/parallel/spec_installation_spec.rb
@@ -0,0 +1,37 @@
+require 'spec_helper'
+require 'bundler/installer/parallel_installer'
+
+describe ParallelInstaller::SpecInstallation do
+  describe "#ready_to_enqueue?" do
+
+    let!(:dep) do
+      a_spec = Object.new
+      def a_spec.name
+        "I like tests"
+      end
+      a_spec
+    end
+
+    context "when in enqueued state" do
+      it "is falsey" do
+        spec = ParallelInstaller::SpecInstallation.new(dep)
+        spec.state = :enqueued
+        expect(spec.ready_to_enqueue?).to be_falsey
+      end
+    end
+
+    context "when in installed state" do
+      it "returns falsey" do
+        spec = ParallelInstaller::SpecInstallation.new(dep)
+        spec.state = :installed
+        expect(spec.ready_to_enqueue?).to be_falsey
+      end
+    end
+
+    it "returns truthy" do
+      spec = ParallelInstaller::SpecInstallation.new(dep)
+      expect(spec.ready_to_enqueue?).to be_truthy
+    end
+  end
+
+end