[ruby/fiddle] Add Fiddle::Closure.create and Fiddle::Closure.free

GitHub: fix GH-102

It's for freeing a closure explicitly.

We can't use Fiddle::Closure before we fork the process. If we do it,
the process may be crashed with SELinux.

See https://github.com/ruby/fiddle/issues/102#issuecomment-1241763091
for details.

Reported by Vít Ondruch. Thanks!!!

https://github.com/ruby/fiddle/commit/a0ccc6bb1b

1 files changed, 25 insertions, 0 deletions

diff --git a/ext/fiddle/lib/fiddle/closure.rb b/ext/fiddle/lib/fiddle/closure.rb
index c865a63c20..7e0077ea52 100644
--- a/ext/fiddle/lib/fiddle/closure.rb
+++ b/ext/fiddle/lib/fiddle/closure.rb
@@ -1,6 +1,31 @@
 # frozen_string_literal: true
 module Fiddle
   class Closure
+    class << self
+      # Create a new closure. If a block is given, the created closure
+      # is automatically freed after the given block is executed.
+      #
+      # The all given arguments are passed to Fiddle::Closure.new. So
+      # using this method without block equals to Fiddle::Closure.new.
+      #
+      # == Example
+      #
+      #   Fiddle::Closure.create(TYPE_INT, [TYPE_INT]) do |closure|
+      #     # closure is freed automatically when this block is finished.
+      #   end
+      def create(*args)
+        if block_given?
+          closure = new(*args)
+          begin
+            yield(closure)
+          ensure
+            closure.free
+          end
+        else
+          new(*args)
+        end
+      end
+    end
 
     # the C type of the return of the FFI closure
     attr_reader :ctype