Revert 'Clean up parallel installer'

It seems like some really bad build instability started with these
changes. This isn't a straight revert, because I accidentally mixed
changes to outdated into the original commit, but this reverts all the
parallel installer changes.

Reverts some of 'a467f7d1f4ded46a519c1f211a75de70c21bc647'.

2 files changed, 53 insertions, 98 deletions

diff --git a/lib/bundler/installer.rb b/lib/bundler/installer.rb
index cd073bde50..10526115a4 100644
--- a/lib/bundler/installer.rb
+++ b/lib/bundler/installer.rb
@@ -1,6 +1,6 @@
 require 'erb'
 require 'rubygems/dependency_installer'
-require 'bundler/installer/parallel_installer'
+require 'bundler/worker'
 
 module Bundler
   class Installer < Environment
@@ -85,7 +85,6 @@ 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]
       else
         install_sequentially options[:standalone]
@@ -261,7 +260,7 @@ module Bundler
 
     def install_sequentially(standalone)
       specs.each do |spec|
-        message = install_gem_from_spec spec, standalone
+        message = install_gem_from_spec spec, standalone, 0
         if message
           Installer.post_install_messages[spec.name] = message
         end
@@ -269,9 +268,59 @@ module Bundler
     end
 
     def install_in_parallel(size, standalone)
-      ParallelInstaller.call(self, specs, size, standalone)
+      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
+        { :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
     end
 
+    # We only want to install a gem spec if all its dependencies are met.
+    # If the dependency is no longer in the `remains` hash then it has been met.
+    # If a dependency is only development or is self referential it can be ignored.
+    def ready_to_install?(spec, remains)
+      spec.dependencies.none? do |dep|
+        next if dep.type == :development || dep.name == spec.name
+        remains[dep.name]
+      end
+    end
 
     def create_bundle_path
       Bundler.mkdir_p(Bundler.bundle_path.to_s) unless Bundler.bundle_path.exist?
diff --git a/lib/bundler/installer/parallel_installer.rb b/lib/bundler/installer/parallel_installer.rb
deleted file mode 100644
index ced75b47b3..0000000000
--- a/lib/bundler/installer/parallel_installer.rb
+++ /dev/null
@@ -1,94 +0,0 @@
-require 'bundler/worker'
-
-
-class ParallelInstaller
-
-  class SpecInstallation
-    attr_accessor :installed, :spec, :name, :post_install_message, :enqueued
-    def initialize(spec)
-      @spec, @name = spec, spec.name
-      @installed = false
-      @enqueued = false
-      @post_install_message = ""
-    end
-
-    def installed?
-      !!installed
-    end
-
-    def has_post_install_message?
-      post_install_message.empty?
-    end
-
-    def enqueued?
-      !!enqueued
-    end
-
-    def installing?
-      !installed? && enqueued?
-    end
-
-    def ready_to_install?(specs)
-      @spec.dependencies.none? do |dep|
-        next if dep.type == :development || dep.name == @name
-        specs.reject(&:installed?).map(&:name).include? dep.name
-      end
-    end
-  end
-
-  def self.call(*options)
-    new(*options).call
-  end
-
-  def self.max_threads
-    @@max_threads ||= [Bundler.settings[:jobs].to_i-1, 1].max
-  end
-
-  def initialize(installer, all_specs, size, standalone)
-    @installer = installer
-    @size = size
-    @standalone = standalone
-    @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
-      spec_install.post_install_message = message unless message.nil?
-      spec_install.installed = true
-      spec_install
-    }
-  end
-
-  def process_specs
-    spec = worker_pool.deq
-    spec.enqueued = false
-    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.reject(&:installing?).each do |spec|
-      if spec.ready_to_install? @specs
-        worker_pool.enq spec
-        spec.enqueued = true
-      end
-    end
-  end
-end