support for GEM_HOME_SHARED

lib/rubygems.rb

@@ -306,6 +306,20 @@ def self.bindir(install_dir=Gem.dir)
     Gem.default_bindir
   end
 
+  ##
+  # The path where gem cache is hold.
+
+  def self.cachedir(install_dir=Gem.dir)
+    # TODO: move to Gem::Dirs
+    if install_dir.to_s == Gem.user_dir.to_s
+      File.join Gem.shared_user_dir, 'cache'
+    elsif Gem.shareddir
+      File.join Gem.shareddir, 'cache'
+    else
+      File.join install_dir, 'cache'
+    end
+  end
+
   ##
   # Reset the +dir+ and +path+ values.  The next time +dir+ or +path+
   # is requested, the values will be calculated from scratch.  This is
@@ -382,6 +396,11 @@ def self.dir
     paths.home
   end
 
+  def self.shareddir
+    # TODO: raise "no"
+    paths.home_shared
+  end
+
   def self.path
     # TODO: raise "no"
     paths.path
@@ -402,6 +421,8 @@ def self.spec_cache_dir
 
   def self.ensure_gem_subdirectories dir = Gem.dir, mode = nil
     ensure_subdirectories(dir, mode, REPOSITORY_SUBDIRECTORIES)
+    ensure_subdirectories(Gem.shared_user_dir, mode, %w[cache]) if dir == Gem.user_dir # :user_install
+    ensure_subdirectories(Gem.shareddir,       mode, %w[cache]) if Gem.shareddir       # GEM_HOME_SHARED
   end
 
   ##

lib/rubygems/commands/cleanup_command.rb

@@ -146,7 +146,7 @@ def uninstall_dep spec
       :version => "= #{spec.version}",
     }
 
-    uninstall_options[:user_install] = Gem.user_dir == spec.base_dir
+    uninstall_options[:user_install] = ((Gem.user_dir == spec.base_dir) or (Gem.shared_user_dir == spec.base_dir))
 
     uninstaller = Gem::Uninstaller.new spec.name, uninstall_options
 

lib/rubygems/defaults.rb

@@ -67,6 +67,14 @@ def self.user_dir
     File.join parts
   end
 
+  ##
+  # Path for shared gems in the user's home directory
+
+  def self.shared_user_dir
+    parts = [Gem.user_home, '.gem', 'shared']
+    File.join parts
+  end
+
   ##
   # How String Gem paths should be split.  Overridable for esoteric platforms.
 
@@ -79,9 +87,9 @@ def self.path_separator
 
   def self.default_path
     if Gem.user_home && File.exist?(Gem.user_home) then
-      [user_dir, default_dir]
+      [ user_dir, shared_user_dir, default_dir ]
     else
-      [default_dir]
+      [ default_dir ]
     end
   end
 

lib/rubygems/installer.rb

@@ -109,11 +109,7 @@ def initialize(gem, options={})
 
     @package.security_policy = @security_policy
 
-    if options[:user_install] and not options[:unpack] then
-      @gem_home = Gem.user_dir
-      @bin_dir = Gem.bindir gem_home unless options[:bin_dir]
-      check_that_user_bin_dir_is_in_path
-    end
+    early_check_user_install
   end
 
   ##
@@ -769,6 +765,42 @@ def dir
     gem_dir.to_s
   end
 
+  ##
+  # For initialization to detect :user_install,
+  # can be changed in try_to_share_gems_location
+
+  def early_check_user_install
+    if options[:user_install] and not options[:unpack] then
+      @gem_home = Gem.user_dir
+      @bin_dir = Gem.bindir gem_home unless options[:bin_dir]
+    end
+  end
+
+  ##
+  # Detect if gems can and should be shared between rubies
+
+  def try_to_share_gems_location
+    if options[:user_install] and not options[:unpack] then
+
+      if spec.can_be_shared?(minimal_shared_gem_version_required) then
+        @gem_home = Gem.shared_user_dir
+        @bin_dir = Gem.bindir gem_home unless options[:bin_dir]
+      end
+      check_that_user_bin_dir_is_in_path
+
+    elsif Gem.shareddir and not options[:unpack] then
+      if spec.can_be_shared?(minimal_shared_gem_version_required) then
+        @gem_home = Gem.shareddir
+        @bin_dir = Gem.bindir gem_home unless options[:bin_dir]
+        check_that_user_bin_dir_is_in_path
+      end
+    end
+  end
+
+  def minimal_shared_gem_version_required
+    @minimal_required_version ||= Gem::Version.new('1.8.7')
+  end
+
   ##
   # Performs various checks before installing the gem such as the install
   # repository is writable and its directories exist, required ruby and
@@ -779,15 +811,17 @@ def dir
   # The dependent check will be skipped this install is ignoring dependencies.
 
   def pre_install_checks
-    verify_gem_home options[:unpack]
-
     # If we're forcing the install then disable security unless the security
     # policy says that we only install signed gems.
     @security_policy = nil if
       @force and @security_policy and not @security_policy.only_signed
 
     ensure_loadable_spec
 
+    try_to_share_gems_location
+
+    verify_gem_home options[:unpack]
+
     if options[:install_as_default]
       Gem.ensure_default_gem_subdirectories gem_home
     else
@@ -827,7 +861,7 @@ def write_build_info_file
   # Writes the .gem file to the cache directory
 
   def write_cache_file
-    cache_file = File.join gem_home, 'cache', spec.file_name
+    cache_file = File.join Gem.cachedir(gem_home), spec.file_name
 
     FileUtils.cp @gem, cache_file unless File.exist? cache_file
   end

lib/rubygems/installer_test_case.rb

@@ -105,7 +105,7 @@ def setup
     @user_gem = @user_spec.cache_file
 
     @installer      = util_installer @spec, @gemhome
-    @user_installer = util_installer @user_spec, Gem.user_dir, :user
+    @user_installer = util_installer @user_spec, Gem.shared_user_dir, :user
   end
 
   def util_gem_bindir spec = @spec # :nodoc:

lib/rubygems/path_support.rb

@@ -8,6 +8,10 @@ class Gem::PathSupport
   # The default system path for managing Gems.
   attr_reader :home
 
+  ##
+  # The shared Gems path, only works together with GEM_HOME.
+  attr_reader :home_shared
+
   ##
   # Array of paths to search for Gems.
   attr_reader :path
@@ -31,6 +35,10 @@ def initialize(env=ENV)
       @home   = @home.gsub(File::ALT_SEPARATOR, File::SEPARATOR)
     end
 
+    if env["GEM_HOME"] || ENV["GEM_HOME"]
+      @home_shared = env["GEM_HOME_SHARED"] || ENV["GEM_HOME_SHARED"]
+    end
+
     self.path = env["GEM_PATH"] || ENV["GEM_PATH"]
 
     @spec_cache_dir =
@@ -49,6 +57,13 @@ def home=(home)
     @home = home.to_s
   end
 
+  ##
+  # Set the Gem home shared directory (as reported by Gem.shareddir).
+
+  def home_shared=(home_shared)
+    @home_shared = home_shared.nil? ? nil : home_shared.to_s
+  end
+
   ##
   # Set the Gem search path (as reported by Gem.path).
 
@@ -74,6 +89,7 @@ def path=(gpaths)
       end
 
       gem_path << @home
+      gem_path << @home_shared if @home_shared
     else
       gem_path = Gem.default_path + [@home]
 

lib/rubygems/remote_fetcher.rb

@@ -121,10 +121,12 @@ def download(spec, source_uri, install_dir = Gem.dir)
     cache_dir =
       if Dir.pwd == install_dir then # see fetch_command
         install_dir
+      elsif Gem.shareddir then
+        File.join Gem.shareddir, "cache"
       elsif File.writable? install_dir then
         File.join install_dir, "cache"
       else
-        File.join Gem.user_dir, "cache"
+        File.join Gem.shared_user_dir, "cache"
       end
 
     gem_file_name = File.basename spec.cache_file

lib/rubygems/specification.rb

@@ -1358,12 +1358,24 @@ def build_info_file
     File.join build_info_dir, "#{full_name}.info"
   end
 
+  ##
+  # True if this gem:
+  # - satisfies the given version
+  # - has platform ruby
+  # - has no extensions
+
+  def can_be_shared?(minimal_required_version)
+    Gem::Requirement.new(required_ruby_version).
+      satisfied_by?(minimal_required_version) &&
+    platform == 'ruby' && extensions.empty?
+  end
+
   ##
   # Returns the full path to the cache directory containing this
   # spec's cached gem.
 
   def cache_dir
-    @cache_dir ||= File.join base_dir, "cache"
+    @cache_dir ||= Gem.cachedir(base_dir)
   end
 
   ##

lib/rubygems/uninstaller.rb

@@ -28,10 +28,21 @@ class Gem::Uninstaller
   attr_reader :bin_dir
 
   ##
-  # The gem repository the gem will be installed into
+  # The user path the gems were installed into,
+  # can be empty - defaults to gem_home
+
+  attr_reader :install_dir
+
+  ##
+  # The gem repository the platform gems were installed into
 
   attr_reader :gem_home
 
+  ##
+  # The gem repository the shared gems were installed into
+
+  attr_reader :gem_home_shared
+
   ##
   # The Gem::Specification for the gem being uninstalled, only set during
   # #uninstall_gem
@@ -45,7 +56,9 @@ def initialize(gem, options = {})
     # TODO document the valid options
     @gem                = gem
     @version            = options[:version] || Gem::Requirement.default
-    @gem_home           = File.expand_path(options[:install_dir] || Gem.dir)
+    @install_dir        = options[:install_dir] ? File.expand_path(options[:install_dir]) : nil
+    @gem_home           = File.expand_path(Gem.dir)
+    @gem_home_shared    = Gem.shareddir ? File.expand_path(Gem.shareddir) : ""
     @force_executables  = options[:executables]
     @force_all          = options[:all]
     @force_ignore       = options[:ignore]
@@ -68,6 +81,14 @@ def initialize(gem, options = {})
     @user_install = options[:user_install] unless options[:install_dir]
   end
 
+  def gem_in_uninstallable_path(base_dir)
+    (
+      install_dir ? install_dir == base_dir : ( @gem_home == base_dir or @gem_home_shared == base_dir )
+    ) or (
+      @user_install and (Gem.user_dir == base_dir or Gem.shared_user_dir == base_dir)
+    )
+  end
+
   ##
   # Performs the uninstall of the gem.  This removes the spec, the Gem
   # directory, and the cached .gem file.
@@ -92,8 +113,7 @@ def uninstall
     end
 
     list, other_repo_specs = list.partition do |spec|
-      @gem_home == spec.base_dir or
-        (@user_install and spec.base_dir == Gem.user_dir)
+      gem_in_uninstallable_path(spec.base_dir)
     end
 
     if list.empty? then
@@ -234,14 +254,7 @@ def remove_all(list)
   # uninstalled a gem, it is removed from that list.
 
   def remove(spec)
-    unless path_ok?(@gem_home, spec) or
-           (@user_install and path_ok?(Gem.user_dir, spec)) then
-      e = Gem::GemNotInHomeException.new \
-            "Gem is not installed in directory #{@gem_home}"
-      e.spec = spec
-
-      raise e
-    end
+    paths_ok_or_raise(spec)
 
     raise Gem::FilePermissionError, spec.base_dir unless
       File.writable?(spec.base_dir)
@@ -274,6 +287,27 @@ def remove(spec)
     Gem::Specification.remove_spec spec
   end
 
+  ##
+  # Confirm spec is one of paths that it can be uninstalled from
+
+  def paths_ok_or_raise(spec)
+    unless (
+             @install_dir ? path_ok?(@install_dir, spec) : (
+               path_ok?(@gem_home, spec) or path_ok?(@gem_home_shared, spec)
+             )
+           ) or (
+             @user_install and (
+               path_ok?(Gem.user_dir, spec) or path_ok?(Gem.shared_user_dir, spec)
+             )
+           ) then
+      e = Gem::GemNotInHomeException.new \
+            "Gem is not installed in directory #{@install_dir ? @install_dir : "#{@gem_home_shared} or #{@gem_home}"}"
+      e.spec = spec
+
+      raise e
+    end
+  end
+
   ##
   # Is +spec+ in +gem_dir+?
 

test/rubygems/test_gem.rb

@@ -476,7 +476,6 @@ def test_self_path_ENV_PATH
 
   def test_self_path_duplicate
     Gem.clear_paths
-    util_ensure_gem_dirs
     dirs = @additional + [@gemhome] + [File.join(@tempdir, 'a')]
 
     ENV['GEM_HOME'] = @gemhome
@@ -491,7 +490,6 @@ def test_self_path_duplicate
   def test_self_path_overlap
     Gem.clear_paths
 
-    util_ensure_gem_dirs
     ENV['GEM_HOME'] = @gemhome
     ENV['GEM_PATH'] = @additional.join(File::PATH_SEPARATOR)
 

test/rubygems/test_gem_commands_cleanup_command.rb

@@ -81,7 +81,7 @@ def test_execute_all_user
     @a_1_1 = quick_spec 'a', '1.1'
     @a_1_1 = install_gem_user @a_1_1 # pick up user install path
 
-    Gem::Specification.dirs = [Gem.dir, Gem.user_dir]
+    Gem::Specification.dirs = [Gem.dir, Gem.shared_user_dir]
 
     assert_path_exists @a_1.gem_dir
     assert_path_exists @a_1_1.gem_dir
@@ -100,7 +100,7 @@ def test_execute_all_user_no_sudo
     @a_1_1 = quick_spec 'a', '1.1'
     @a_1_1 = install_gem_user @a_1_1 # pick up user install path
 
-    Gem::Specification.dirs = [Gem.dir, Gem.user_dir]
+    Gem::Specification.dirs = [Gem.dir, Gem.shared_user_dir]
 
     assert_path_exists @a_1.gem_dir
     assert_path_exists @a_1_1.gem_dir