1 files changed, 144 insertions, 0 deletions
diff --git a/lib/rubygems/validator.rb b/lib/rubygems/validator.rb
new file mode 100644
index 0000000000..eb5b513570
--- /dev/null
+++ b/lib/rubygems/validator.rb
@@ -0,0 +1,144 @@
+# frozen_string_literal: true
+
+#--
+# Copyright 2006 by Chad Fowler, Rich Kilmer, Jim Weirich and others.
+# All rights reserved.
+# See LICENSE.txt for permissions.
+#++
+
+require_relative "package"
+require_relative "installer"
+
+##
+# Validator performs various gem file and gem database validation
+
+class Gem::Validator
+  include Gem::UserInteraction
+
+  def initialize # :nodoc:
+    require "find"
+  end
+
+  private
+
+  def find_files_for_gem(gem_directory)
+    installed_files = []
+
+    Find.find gem_directory do |file_name|
+      fn = file_name[gem_directory.size..file_name.size - 1].sub(%r{^/}, "")
+      installed_files << fn unless
+        fn.empty? || fn.include?("CVS") || File.directory?(file_name)
+    end
+
+    installed_files
+  end
+
+  public
+
+  ##
+  # Describes a problem with a file in a gem.
+
+  ErrorData = Struct.new :path, :problem do
+    def <=>(other) # :nodoc:
+      return nil unless self.class === other
+
+      [path, problem] <=> [other.path, other.problem]
+    end
+  end
+
+  ##
+  # Checks the gem directory for the following potential
+  # inconsistencies/problems:
+  #
+  # * Checksum gem itself
+  # * For each file in each gem, check consistency of installed versions
+  # * Check for files that aren't part of the gem but are in the gems directory
+  # * 1 cache - 1 spec - 1 directory.
+  #
+  # returns a hash of ErrorData objects, keyed on the problem gem's name.
+  #--
+  # TODO needs further cleanup
+
+  def alien(gems = [])
+    errors = Hash.new {|h,k| h[k] = {} }
+
+    Gem::Specification.each do |spec|
+      unless gems.empty?
+        next unless gems.include? spec.name
+      end
+      next if spec.default_gem?
+
+      gem_name      = spec.file_name
+      gem_path      = spec.cache_file
+      spec_path     = spec.spec_file
+      gem_directory = spec.full_gem_path
+
+      unless File.directory? gem_directory
+        errors[gem_name][spec.full_name] =
+          "Gem registered but doesn't exist at #{gem_directory}"
+        next
+      end
+
+      unless File.exist? spec_path
+        errors[gem_name][spec_path] = "Spec file missing for installed gem"
+      end
+
+      begin
+        unless File.readable?(gem_path)
+          raise Gem::VerificationError, "missing gem file #{gem_path}"
+        end
+
+        good, gone, unreadable = nil, nil, nil, nil
+
+        File.open gem_path, Gem.binary_mode do |_file|
+          package = Gem::Package.new gem_path
+
+          good, gone = package.contents.partition do |file_name|
+            File.exist? File.join(gem_directory, file_name)
+          end
+
+          gone.sort.each do |path|
+            errors[gem_name][path] = "Missing file"
+          end
+
+          good, unreadable = good.partition do |file_name|
+            File.readable? File.join(gem_directory, file_name)
+          end
+
+          unreadable.sort.each do |path|
+            errors[gem_name][path] = "Unreadable file"
+          end
+
+          good.each do |entry, data|
+            next unless data # HACK: `gem check -a mkrf`
+
+            source = File.join gem_directory, entry["path"]
+
+            File.open source, Gem.binary_mode do |f|
+              unless f.read == data
+                errors[gem_name][entry["path"]] = "Modified from original"
+              end
+            end
+          end
+        end
+
+        installed_files = find_files_for_gem(gem_directory)
+        extras = installed_files - good - unreadable
+
+        extras.each do |extra|
+          errors[gem_name][extra] = "Extra file"
+        end
+      rescue Gem::VerificationError => e
+        errors[gem_name][gem_path] = e.message
+      end
+    end
+
+    errors.each do |name, subhash|
+      errors[name] = subhash.map do |path, msg|
+        ErrorData.new path, msg
+      end.sort
+    end
+
+    errors
+  end
+end