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Diffstat (limited to 'lib/rubygems/core_ext/kernel_require.rb')
-rwxr-xr-x | lib/rubygems/core_ext/kernel_require.rb | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/lib/rubygems/core_ext/kernel_require.rb b/lib/rubygems/core_ext/kernel_require.rb new file mode 100755 index 0000000000..e6dfce644f --- /dev/null +++ b/lib/rubygems/core_ext/kernel_require.rb @@ -0,0 +1,119 @@ +#-- +# Copyright 2006 by Chad Fowler, Rich Kilmer, Jim Weirich and others. +# All rights reserved. +# See LICENSE.txt for permissions. +#++ + +module Kernel + + if defined?(gem_original_require) then + # Ruby ships with a custom_require, override its require + remove_method :require + else + ## + # The Kernel#require from before RubyGems was loaded. + + alias gem_original_require require + private :gem_original_require + end + + ## + # When RubyGems is required, Kernel#require is replaced with our own which + # is capable of loading gems on demand. + # + # When you call <tt>require 'x'</tt>, this is what happens: + # * If the file can be loaded from the existing Ruby loadpath, it + # is. + # * Otherwise, installed gems are searched for a file that matches. + # If it's found in gem 'y', that gem is activated (added to the + # loadpath). + # + # The normal <tt>require</tt> functionality of returning false if + # that file has already been loaded is preserved. + + def require path + spec = Gem.find_unresolved_default_spec(path) + if spec + Gem.remove_unresolved_default_spec(spec) + gem(spec.name) + end + + # If there are no unresolved deps, then we can use just try + # normal require handle loading a gem from the rescue below. + + if Gem::Specification.unresolved_deps.empty? then + return gem_original_require(path) + end + + # If +path+ is for a gem that has already been loaded, don't + # bother trying to find it in an unresolved gem, just go straight + # to normal require. + #-- + # TODO request access to the C implementation of this to speed up RubyGems + + spec = Gem::Specification.find { |s| + s.activated? and s.contains_requirable_file? path + } + + return gem_original_require(path) if spec + + # Attempt to find +path+ in any unresolved gems... + + found_specs = Gem::Specification.find_in_unresolved path + + # If there are no directly unresolved gems, then try and find +path+ + # in any gems that are available via the currently unresolved gems. + # For example, given: + # + # a => b => c => d + # + # If a and b are currently active with c being unresolved and d.rb is + # requested, then find_in_unresolved_tree will find d.rb in d because + # it's a dependency of c. + # + if found_specs.empty? then + found_specs = Gem::Specification.find_in_unresolved_tree path + + found_specs.each do |found_spec| + found_spec.activate + end + + # We found +path+ directly in an unresolved gem. Now we figure out, of + # the possible found specs, which one we should activate. + else + + # Check that all the found specs are just different + # versions of the same gem + names = found_specs.map(&:name).uniq + + if names.size > 1 then + raise Gem::LoadError, "#{path} found in multiple gems: #{names.join ', '}" + end + + # Ok, now find a gem that has no conflicts, starting + # at the highest version. + valid = found_specs.select { |s| s.conflicts.empty? }.last + + unless valid then + le = Gem::LoadError.new "unable to find a version of '#{names.first}' to activate" + le.name = names.first + raise le + end + + valid.activate + end + + gem_original_require path + rescue LoadError => load_error + if load_error.message.start_with?("Could not find") or + (load_error.message.end_with?(path) and Gem.try_activate(path)) then + return gem_original_require(path) + end + + raise load_error + end + + private :require + +end + |