merges r28693, r28695 and r28703 from trunk into ruby_1_9_2.

--
* lib/rubygems/custom_require.rb, gem_prelude.rb: Load code from
  from gems properly.

* lib/rubygems.rb: Load the custom require if --disable-rubygems
  was used.

* gem_prelude.rb: Pull in rubygem's custom require
  [ruby-core:30846]

* lib/rubygems.rb: Handle always having custom require available

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@28786 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 28 insertions, 97 deletions

diff --git a/gem_prelude.rb b/gem_prelude.rb
index c51f07ef08..017adc2040 100644
--- a/gem_prelude.rb
+++ b/gem_prelude.rb
@@ -13,7 +13,8 @@ if defined?(Gem) then
   module Kernel
 
     def gem(gem_name, *version_requirements)
-      Gem.push_gem_version_on_load_path(gem_name, *version_requirements)
+      Gem::QuickLoader.load_full_rubygems_library
+      gem gem_name, *version_requirements
     end
     private :gem
   end
@@ -143,17 +144,18 @@ if defined?(Gem) then
 
         class << Gem
           undef_method(*Gem::GEM_PRELUDE_METHODS)
-          undef_method :const_missing
-          undef_method :method_missing
         end
 
+        remove_method :const_missing
+        remove_method :method_missing
+
         Kernel.module_eval do
           undef_method :gem if method_defined? :gem
         end
       end
 
       def self.load_full_rubygems_library
-        return if @loaded_full_rubygems_library
+        return false if @loaded_full_rubygems_library
 
         remove
 
@@ -161,12 +163,10 @@ if defined?(Gem) then
         if $".any? {|path| path.end_with?('/rubygems.rb')}
           raise LoadError, "another rubygems is already loaded from #{path}"
         end
+
         require 'rubygems'
-      end
 
-      def self.fake_rubygems_as_loaded
-        path = path_to_full_rubygems_library
-        $" << path unless $".include?(path)
+        return true
       end
 
       def self.path_to_full_rubygems_library
@@ -183,94 +183,6 @@ if defined?(Gem) then
         end
       end
 
-      GemPaths = {}
-      GemVersions = {}
-      GemLoadPaths = []
-
-      def push_gem_version_on_load_path(gem_name, *version_requirements)
-        if version_requirements.empty?
-          unless GemPaths.has_key?(gem_name) then
-            raise Gem::LoadError, "Could not find RubyGem #{gem_name} (>= 0)\n"
-          end
-
-          # highest version gems already active
-          return false
-        else
-          if version_requirements.length > 1 then
-            QuickLoader.load_full_rubygems_library
-            return gem(gem_name, *version_requirements)
-          end
-
-          requirement, version = version_requirements[0].split
-          requirement.strip!
-
-          if loaded_version = GemVersions[gem_name] then
-            case requirement
-            when ">", ">=" then
-              return false if
-                (loaded_version <=> Gem.integers_for(version)) >= 0
-            when "~>" then
-              required_version = Gem.integers_for version
-
-              return false if loaded_version.first == required_version.first
-            end
-          end
-
-          QuickLoader.load_full_rubygems_library
-          gem gem_name, *version_requirements
-        end
-      end
-
-      def integers_for(gem_version)
-        numbers = gem_version.split(".").collect {|n| n.to_i}
-        numbers.pop while numbers.last == 0
-        numbers << 0 if numbers.empty?
-        numbers
-      end
-
-      def push_all_highest_version_gems_on_load_path
-        Gem.path.each do |path|
-          gems_directory = File.join(path, "gems")
-
-          if File.exist?(gems_directory) then
-            Dir.entries(gems_directory).each do |gem_directory_name|
-              next if gem_directory_name == "." || gem_directory_name == ".."
-
-              next unless gem_name = gem_directory_name[/(.*)-(.*)/, 1]
-              new_version = integers_for($2)
-              current_version = GemVersions[gem_name]
-
-              if !current_version or (current_version <=> new_version) < 0 then
-                GemVersions[gem_name] = new_version
-                GemPaths[gem_name] = File.join(gems_directory, gem_directory_name)
-              end
-            end
-          end
-        end
-
-        GemPaths.each_value do |path|
-          if File.exist?(file = File.join(path, ".require_paths")) then
-            paths = File.read(file).split.map do |require_path|
-              File.join path, require_path
-            end
-
-            GemLoadPaths.concat paths
-          else
-            GemLoadPaths << file if File.exist?(file = File.join(path, "bin"))
-            GemLoadPaths << file if File.exist?(file = File.join(path, "lib"))
-          end
-        end
-
-        # "tag" the first require_path inserted into the $LOAD_PATH to enable
-        # indexing correctly with rubygems proper when it inserts an explicitly
-        # gem version
-        unless GemLoadPaths.empty? then
-          GemLoadPaths.first.instance_variable_set(:@gem_prelude_index, true)
-        end
-        # gem directories must come after -I and ENV['RUBYLIB']
-        $:[$:.index{|e|e.instance_variable_defined?(:@gem_prelude_index)}||-1,0] = GemLoadPaths
-      end
-
       def const_missing(constant)
         QuickLoader.load_full_rubygems_library
 
@@ -290,10 +202,29 @@ if defined?(Gem) then
 
     extend QuickLoader
 
+    def self.try_activate(path)
+      # This method is only hit when the custom require is hit the first time.
+      # So we go off and dutifully load all of rubygems and retry the call
+      # to Gem.try_activate. We retry because full rubygems replaces this
+      # method with one that actually tries to find a gem for +path+ and load it.
+      #
+      # This is conditional because in the course of loading rubygems, the custom
+      # require will call back into here before all of rubygems is loaded. So
+      # we must not always retry the call. We only redo the call when
+      # load_full_rubygems_library returns true, which it only does the first
+      # time it's called.
+      #
+      if QuickLoader.load_full_rubygems_library
+        return Gem.try_activate(path)
+      end
+
+      return false
+    end
+
   end
 
   begin
-    Gem.push_all_highest_version_gems_on_load_path
+    require 'lib/rubygems/custom_require.rb'
   rescue Exception => e
     puts "Error loading gem paths on load path in gem_prelude"
     puts e