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75 lines
2.4 KiB
Ruby
75 lines
2.4 KiB
Ruby
# frozen_string_literal: true
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##
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# RubyGems adds the #gem method to allow activation of specific gem versions
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# and overrides the #require method on Kernel to make gems appear as if they
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# live on the <code>$LOAD_PATH</code>. See the documentation of these methods
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# for further detail.
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module Kernel
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##
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# Use Kernel#gem to activate a specific version of +gem_name+.
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#
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# +requirements+ is a list of version requirements that the
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# specified gem must match, most commonly "= example.version.number". See
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# Gem::Requirement for how to specify a version requirement.
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#
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# If you will be activating the latest version of a gem, there is no need to
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# call Kernel#gem, Kernel#require will do the right thing for you.
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#
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# Kernel#gem returns true if the gem was activated, otherwise false. If the
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# gem could not be found, didn't match the version requirements, or a
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# different version was already activated, an exception will be raised.
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#
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# Kernel#gem should be called *before* any require statements (otherwise
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# RubyGems may load a conflicting library version).
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#
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# Kernel#gem only loads prerelease versions when prerelease +requirements+
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# are given:
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#
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# gem 'rake', '>= 1.1.a', '< 2'
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#
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# In older RubyGems versions, the environment variable GEM_SKIP could be
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# used to skip activation of specified gems, for example to test out changes
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# that haven't been installed yet. Now RubyGems defers to -I and the
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# RUBYLIB environment variable to skip activation of a gem.
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#
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# Example:
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#
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# GEM_SKIP=libA:libB ruby -I../libA -I../libB ./mycode.rb
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def gem(gem_name, *requirements) # :doc:
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skip_list = (ENV['GEM_SKIP'] || "").split(/:/)
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raise Gem::LoadError, "skipping #{gem_name}" if skip_list.include? gem_name
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if gem_name.kind_of? Gem::Dependency
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unless Gem::Deprecate.skip
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warn "#{Gem.location_of_caller.join ':'}:Warning: Kernel.gem no longer "\
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"accepts a Gem::Dependency object, please pass the name "\
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"and requirements directly"
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end
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requirements = gem_name.requirement
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gem_name = gem_name.name
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end
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dep = Gem::Dependency.new(gem_name, *requirements)
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loaded = Gem.loaded_specs[gem_name]
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return false if loaded && dep.matches_spec?(loaded)
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spec = dep.to_spec
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if spec
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if Gem::LOADED_SPECS_MUTEX.owned?
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spec.activate
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else
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Gem::LOADED_SPECS_MUTEX.synchronize { spec.activate }
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end
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end
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end
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private :gem
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end
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