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-rw-r--r--lib/weakref.rb18
1 files changed, 14 insertions, 4 deletions
diff --git a/lib/weakref.rb b/lib/weakref.rb
index 49b907ba17..142286e765 100644
--- a/lib/weakref.rb
+++ b/lib/weakref.rb
@@ -1,4 +1,11 @@
-# Weak Reference class that does not bother GCing.
+
+require "delegate"
+
+# Weak Reference class that does not bother GCing. This allows the
+# referenced object to be garbage collected as if nothing else is
+# referring to it. Because Weakref inherits from Delegator it passes
+# method calls to the object from which it was constructed, so it
+# is of the same Duck Type.
#
# Usage:
# foo = Object.new
@@ -8,11 +15,9 @@
# p foo.to_s # should be same class
# ObjectSpace.garbage_collect
# p foo.to_s # should raise exception (recycled)
-
-require "delegate"
-
class WeakRef<Delegator
+ # RefError is raised if an object cannot be referenced by a WeakRef.
class RefError<StandardError
end
@@ -40,6 +45,7 @@ class WeakRef<Delegator
end
}
+ # Create a new WeakRef from +orig+.
def initialize(orig)
super
@__id = orig.__id__
@@ -56,6 +62,9 @@ class WeakRef<Delegator
@@id_rev_map[self.__id__] = @__id
end
+ # Return the object this WeakRef references. Raise
+ # RefError if this is impossible. The object is that
+ # to which method calls are delegated (see Delegator).
def __getobj__
unless @@id_rev_map[self.__id__] == @__id
raise RefError, "Illegal Reference - probably recycled", caller(2)
@@ -67,6 +76,7 @@ class WeakRef<Delegator
end
end
+ # Determine if this Weakref still refers to anything.
def weakref_alive?
@@id_rev_map[self.__id__] == @__id
end