126 lines
4.2 KiB
Ruby
126 lines
4.2 KiB
Ruby
class Pry
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class Method
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class Patcher
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attr_accessor :method
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@@source_cache = {}
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def initialize(method)
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@method = method
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end
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def self.code_for(filename)
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@@source_cache[filename]
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end
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# perform the patch
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def patch_in_ram(source)
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if method.alias?
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with_method_transaction do
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redefine source
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end
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else
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redefine source
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end
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end
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private
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def redefine(source)
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@@source_cache[cache_key] = source
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TOPLEVEL_BINDING.eval wrap(source), cache_key
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end
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def cache_key
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"pry-redefined(0x#{method.owner.object_id.to_s(16)}##{method.name})"
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end
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# Run some code ensuring that at the end target#meth_name will not have changed.
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#
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# When we're redefining aliased methods we will overwrite the method at the
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# unaliased name (so that super continues to work). By wrapping that code in a
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# transation we make that not happen, which means that alias_method_chains, etc.
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# continue to work.
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#
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# @param [String] meth_name The method name before aliasing
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# @param [Module] target The owner of the method
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def with_method_transaction
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temp_name = "__pry_#{method.original_name}__"
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method = self.method
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method.owner.class_eval do
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alias_method temp_name, method.original_name
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yield
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alias_method method.name, method.original_name
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alias_method method.original_name, temp_name
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end
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ensure
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method.send(:remove_method, temp_name) rescue nil
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end
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# Update the definition line so that it can be eval'd directly on the Method's
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# owner instead of from the original context.
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#
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# In particular this takes `def self.foo` and turns it into `def foo` so that we
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# don't end up creating the method on the singleton class of the singleton class
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# by accident.
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#
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# This is necessarily done by String manipulation because we can't find out what
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# syntax is needed for the argument list by ruby-level introspection.
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#
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# @param [String] line The original definition line. e.g. def self.foo(bar, baz=1)
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# @return [String] The new definition line. e.g. def foo(bar, baz=1)
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def definition_for_owner(line)
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if line =~ /\Adef (?:.*?\.)?#{Regexp.escape(method.original_name)}(?=[\(\s;]|$)/
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"def #{method.original_name}#{$'}"
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else
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raise CommandError, "Could not find original `def #{method.original_name}` line to patch."
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end
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end
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# Apply wrap_for_owner and wrap_for_nesting successively to `source`
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# @param [String] source
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# @return [String] The wrapped source.
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def wrap(source)
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wrap_for_nesting(wrap_for_owner(source))
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end
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# Update the source code so that when it has the right owner when eval'd.
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#
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# This (combined with definition_for_owner) is backup for the case that
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# wrap_for_nesting fails, to ensure that the method will stil be defined in
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# the correct place.
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#
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# @param [String] source The source to wrap
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# @return [String]
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def wrap_for_owner(source)
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Pry.current[:pry_owner] = method.owner
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owner_source = definition_for_owner(source)
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visibility_fix = "#{method.visibility.to_s} #{method.name.to_sym.inspect}"
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"Pry.current[:pry_owner].class_eval do; #{owner_source}\n#{visibility_fix}\nend"
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end
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# Update the new source code to have the correct Module.nesting.
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#
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# This method uses syntactic analysis of the original source file to determine
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# the new nesting, so that we can tell the difference between:
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#
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# class A; def self.b; end; end
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# class << A; def b; end; end
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#
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# The resulting code should be evaluated in the TOPLEVEL_BINDING.
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#
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# @param [String] source The source to wrap.
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# @return [String]
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def wrap_for_nesting(source)
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nesting = Pry::Code.from_file(method.source_file).nesting_at(method.source_line)
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(nesting + [source] + nesting.map{ "end" } + [""]).join(";")
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rescue Pry::Indent::UnparseableNestingError
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source
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end
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end
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end
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end
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