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PATH: opt / alt / ruby24 / lib64 / ruby / 2.4.0

# frozen_string_literal: false
require "delegate"

# Weak Reference class that allows a referenced object to be
# garbage-collected.
#
# A WeakRef may be used exactly like the object it references.
#
# Usage:
#
#   foo = Object.new            # create a new object instance
#   p foo.to_s                  # original's class
#   foo = WeakRef.new(foo)      # reassign foo with WeakRef instance
#   p foo.to_s                  # should be same class
#   GC.start                    # start the garbage collector
#   p foo.to_s                  # should raise exception (recycled)
#
# == Example
#
# With help from WeakRef, we can implement our own rudimentary WeakHash class.
#
# We will call it WeakHash, since it's really just a Hash except all of it's
# keys and values can be garbage collected.
#
#     require 'weakref'
#
#     class WeakHash < Hash
#       def []= key, obj
#         super WeakRef.new(key), WeakRef.new(obj)
#       end
#     end
#
# This is just a simple implementation, we've opened the Hash class and changed
# Hash#store to create a new WeakRef object with +key+ and +obj+ parameters
# before passing them as our key-value pair to the hash.
#
# With this you will have to limit your self to String keys, otherwise you
# will get an ArgumentError because WeakRef cannot create a finalizer for a
# Symbol. Symbols are immutable and cannot be garbage collected.
#
# Let's see it in action:
#
#   omg = "lol"
#   c = WeakHash.new
#   c['foo'] = "bar"
#   c['baz'] = Object.new
#   c['qux'] = omg
#   puts c.inspect
#   #=> {"foo"=>"bar", "baz"=>#<Object:0x007f4ddfc6cb48>, "qux"=>"lol"}
#
#   # Now run the garbage collector
#   GC.start
#   c['foo'] #=> nil
#   c['baz'] #=> nil
#   c['qux'] #=> nil
#   omg      #=> "lol"
#
#   puts c.inspect
#   #=> WeakRef::RefError: Invalid Reference - probably recycled
#
# You can see the local variable +omg+ stayed, although its reference in our
# hash object was garbage collected, along with the rest of the keys and
# values. Also, when we tried to inspect our hash, we got a WeakRef::RefError.
# This is because these objects were also garbage collected.

class WeakRef < Delegator

##
  # RefError is raised when a referenced object has been recycled by the
  # garbage collector

class RefError < StandardError
  end

@@__map = ::ObjectSpace::WeakMap.new

##
  # Creates a weak reference to +orig+
  #
  # Raises an ArgumentError if the given +orig+ is immutable, such as Symbol,
  # Integer, or Float.

def initialize(orig)
    case orig
    when true, false, nil
      @delegate_sd_obj = orig
    else
      @@__map[self] = orig
    end
    super
  end

def __getobj__ # :nodoc:
    @@__map[self] or defined?(@delegate_sd_obj) ? @delegate_sd_obj :
      Kernel::raise(RefError, "Invalid Reference - probably recycled", Kernel::caller(2))
  end

def __setobj__(obj) # :nodoc:
  end

##
  # Returns true if the referenced object is still alive.

def weakref_alive?
    @@__map.key?(self) or defined?(@delegate_sd_obj)
  end
end

[+] rinda
[+] yaml
[-] matrix.rb [edit]
[+] rdoc
[-] shell.rb [edit]
[-] ostruct.rb [edit]
[-] scanf.rb [edit]
[+] ripper
[-] rdoc.rb [edit]
[-] getoptlong.rb [edit]
[-] sync.rb [edit]
[-] delegate.rb [edit]
[-] open-uri.rb [edit]
[-] json.rb [edit]
[-] rubygems.rb [edit]
[-] openssl.rb [edit]
[+] json
[-] debug.rb [edit]
[+] irb
[-] digest.rb [edit]
[-] yaml.rb [edit]
[-] forwardable.rb [edit]
[-] weakref.rb [edit]
[-] benchmark.rb [edit]
[-] profiler.rb [edit]
[-] uri.rb [edit]
[-] English.rb [edit]
[+] syslog
[-] timeout.rb [edit]
[+] rbconfig
[-] tracer.rb [edit]
[-] resolv.rb [edit]
[+] uri
[-] tsort.rb [edit]
[-] find.rb [edit]
[-] logger.rb [edit]
[-] psych.rb [edit]
[+] psych
[-] ubygems.rb [edit]
[-] profile.rb [edit]
[-] optparse.rb [edit]
[+] matrix
[-] pp.rb [edit]
[-] date.rb [edit]
[-] cmath.rb [edit]
[-] ripper.rb [edit]
[-] fiddle.rb [edit]
[+] drb
[+] io
[+] webrick
[+] unicode_normalize
[-] cgi.rb [edit]
[-] pathname.rb [edit]
[-] mutex_m.rb [edit]
[-] unicode_normalize.rb [edit]
[+] rss
[+] racc
[+] forwardable
[+] ..
[-] prettyprint.rb [edit]
[-] csv.rb [edit]
[-] kconv.rb [edit]
[-] securerandom.rb [edit]
[+] fiddle
[-] abbrev.rb [edit]
[-] resolv-replace.rb [edit]
[+] digest
[-] mathn.rb [edit]
[+] rexml
[-] optionparser.rb [edit]
[-] e2mmap.rb [edit]
[-] shellwords.rb [edit]
[-] rss.rb [edit]
[-] time.rb [edit]
[+] openssl
[-] fileutils.rb [edit]
[-] socket.rb [edit]
[+] net
[-] monitor.rb [edit]
[-] tempfile.rb [edit]
[-] un.rb [edit]
[-] mkmf.rb [edit]
[-] base64.rb [edit]
[-] thwait.rb [edit]
[-] webrick.rb [edit]
[-] erb.rb [edit]
[+] shell
[-] expect.rb [edit]
[-] open3.rb [edit]
[+] cgi
[-] tmpdir.rb [edit]
[-] ipaddr.rb [edit]
[-] pstore.rb [edit]
[-] singleton.rb [edit]
[+] rubygems
[-] set.rb [edit]
[-] observer.rb [edit]
[-] drb.rb [edit]
[-] irb.rb [edit]
[-] prime.rb [edit]
[+] x86_64-linux
[+] optparse