1 files changed, 189 insertions, 0 deletions
diff --git a/lib/rubygems/source/git.rb b/lib/rubygems/source/git.rb
new file mode 100644
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+++ b/lib/rubygems/source/git.rb
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+require 'digest'
+require 'rubygems/util'
+
+##
+# A git gem for use in a gem dependencies file.
+#
+# Example:
+#
+#   source =
+#     Gem::Source::Git.new 'rake', 'git@example:rake.git', 'rake-10.1.0', false
+#
+#   spec = source.load_spec 'rake'
+#
+#   source.checkout
+
+class Gem::Source::Git < Gem::Source
+
+  ##
+  # The name of the gem created by this git gem.
+
+  attr_reader :name
+
+  ##
+  # The commit reference used for checking out this git gem.
+
+  attr_reader :reference
+
+  ##
+  # The git repository this gem is sourced from.
+
+  attr_reader :repository
+
+  ##
+  # Does this repository need submodules checked out too?
+
+  attr_reader :need_submodules
+
+  ##
+  # Creates a new git gem source for a gem with the given +name+ that will be
+  # loaded from +reference+ in +repository+.  If +submodules+ is true,
+  # submodules will be checked out when the gem is installed.
+
+  def initialize name, repository, reference, submodules = false
+    super(nil)
+
+    @name            = name
+    @repository      = repository
+    @reference       = reference
+    @need_submodules = submodules
+
+    @git = ENV['git'] || 'git'
+  end
+
+  def <=> other
+    case other
+    when Gem::Source::Git then
+      0
+    when Gem::Source::Installed then
+      -1
+    when Gem::Source then
+      1
+    else
+      nil
+    end
+  end
+
+  def == other # :nodoc:
+    super and
+      @name            == other.name and
+      @repository      == other.repository and
+      @reference       == other.reference and
+      @need_submodules == other.need_submodules
+  end
+
+  ##
+  # Checks out the files for the repository into the install_dir.
+
+  def checkout # :nodoc:
+    cache
+
+    unless File.exist? install_dir then
+      system @git, 'clone', '--quiet', '--no-checkout',
+             repo_cache_dir, install_dir
+    end
+
+    Dir.chdir install_dir do
+      system @git, 'fetch', '--quiet', '--force', '--tags', install_dir
+
+      success = system @git, 'reset', '--quiet', '--hard', @reference
+
+      success &&=
+        system @git, 'submodule', 'update',
+               '--quiet', '--init', '--recursive' if @need_submodules
+
+      success
+    end
+  end
+
+  ##
+  # Creates a local cache repository for the git gem.
+
+  def cache # :nodoc:
+    if File.exist? repo_cache_dir then
+      Dir.chdir repo_cache_dir do
+        system @git, 'fetch', '--quiet', '--force', '--tags',
+               @repository, 'refs/heads/*:refs/heads/*'
+      end
+    else
+      system @git, 'clone', '--quiet', '--bare', '--no-hardlinks',
+             @repository, repo_cache_dir
+    end
+  end
+
+  ##
+  # A short reference for use in git gem directories
+
+  def dir_shortref # :nodoc:
+    rev_parse[0..11]
+  end
+
+  ##
+  # The directory where the git gem will be installed.
+
+  def install_dir # :nodoc:
+    File.join Gem.dir, 'bundler', 'gems', "#{@name}-#{dir_shortref}"
+  end
+
+  ##
+  # Loads a Gem::Specification for +name+ from this git repository.
+
+  def load_spec name
+    cache
+
+    gemspec_reference = "#{@reference}:#{name}.gemspec"
+
+    Dir.chdir repo_cache_dir do
+      source = Gem::Util.popen @git, 'show', gemspec_reference
+
+      source.force_encoding Encoding::UTF_8 if Object.const_defined? :Encoding
+      source.untaint
+
+      begin
+        spec = eval source, binding, gemspec_reference
+
+        return spec if Gem::Specification === spec
+
+        warn "git gem specification for #{@repository} #{gemspec_reference} is not a Gem::Specification (#{spec.class} instead)."
+      rescue SignalException, SystemExit
+        raise
+      rescue SyntaxError, Exception
+        warn "invalid git gem specification for #{@repository} #{gemspec_reference}"
+      end
+    end
+  end
+
+  ##
+  # The directory where the git gem's repository will be cached.
+
+  def repo_cache_dir # :nodoc:
+    File.join Gem.dir, 'cache', 'bundler', 'git', "#{@name}-#{uri_hash}"
+  end
+
+  ##
+  # Converts the git reference for the repository into a commit hash.
+
+  def rev_parse # :nodoc:
+    # HACK no safe equivalent of ` exists on 1.8.7
+    Dir.chdir repo_cache_dir do
+      Gem::Util.popen(@git, 'rev-parse', @reference).strip
+    end
+  end
+
+  ##
+  # A hash for the git gem based on the git repository URI.
+
+  def uri_hash # :nodoc:
+    normalized =
+      if @repository =~ %r%^\w+://(\w+@)?% then
+        uri = URI(@repository).normalize.to_s.sub %r%/$%,''
+        uri.sub(/\A(\w+)/) { $1.downcase }
+      else
+        @repository
+      end
+
+    Digest::SHA1.hexdigest normalized
+  end
+
+end
+