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ca96541149
by Luke Gruber. [#5203] * ext/pty/lib/expect.rb: ditto * lib/mathn.rb: ditto * lib/net/http.rb: ditto * lib/open-uri.rb: ditto * lib/ostruct.rb: ditto * lib/tempfile.rb: ditto * lib/thread.rb: ditto * lib/weakref.rb: ditto * sample/webrick/httpproxy.rb: ditto git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@33086 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
94 lines
2.3 KiB
Ruby
94 lines
2.3 KiB
Ruby
require "delegate"
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require 'thread'
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# Weak Reference class that allows a referenced object to be
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# garbage-collected. A WeakRef may be used exactly like the object it
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# references.
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#
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# Usage:
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#
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# foo = Object.new
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# foo = Object.new
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# p foo.to_s # original's class
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# foo = WeakRef.new(foo)
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# p foo.to_s # should be same class
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# ObjectSpace.garbage_collect
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# p foo.to_s # should raise exception (recycled)
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class WeakRef < Delegator
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##
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# RefError is raised when a referenced object has been recycled by the
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# garbage collector
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class RefError < StandardError
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end
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@@id_map = {} # obj -> [ref,...]
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@@id_rev_map = {} # ref -> obj
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@@mutex = Mutex.new
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@@final = lambda {|id|
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@@mutex.synchronize {
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rids = @@id_map[id]
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if rids
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for rid in rids
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@@id_rev_map.delete(rid)
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end
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@@id_map.delete(id)
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end
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rid = @@id_rev_map[id]
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if rid
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@@id_rev_map.delete(id)
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@@id_map[rid].delete(id)
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@@id_map.delete(rid) if @@id_map[rid].empty?
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end
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}
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}
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##
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# Creates a weak reference to +orig+
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def initialize(orig)
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@__id = orig.object_id
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ObjectSpace.define_finalizer orig, @@final
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ObjectSpace.define_finalizer self, @@final
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@@mutex.synchronize {
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@@id_map[@__id] = [] unless @@id_map[@__id]
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}
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@@id_map[@__id].push self.object_id
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@@id_rev_map[self.object_id] = @__id
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super
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end
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def __getobj__ # :nodoc:
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unless @@id_rev_map[self.object_id] == @__id
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Kernel::raise RefError, "Invalid Reference - probably recycled", Kernel::caller(2)
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end
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begin
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ObjectSpace._id2ref(@__id)
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rescue RangeError
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Kernel::raise RefError, "Invalid Reference - probably recycled", Kernel::caller(2)
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end
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end
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def __setobj__(obj) # :nodoc:
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end
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##
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# Returns true if the referenced object is still alive.
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def weakref_alive?
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@@id_rev_map[self.object_id] == @__id
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end
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end
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if __FILE__ == $0
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# require 'thread'
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foo = Object.new
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p foo.to_s # original's class
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foo = WeakRef.new(foo)
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p foo.to_s # should be same class
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ObjectSpace.garbage_collect
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ObjectSpace.garbage_collect
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p foo.to_s # should raise exception (recycled)
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end
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