| # Copyright (C) 2008 Mike Dalessio |
| # |
| # This file is part of ruby-ffi. |
| # |
| # All rights reserved. |
| # |
| # Redistribution and use in source and binary forms, with or without |
| # modification, are permitted provided that the following conditions are met: |
| # |
| # * Redistributions of source code must retain the above copyright notice, this |
| # list of conditions and the following disclaimer. |
| # * Redistributions in binary form must reproduce the above copyright notice |
| # this list of conditions and the following disclaimer in the documentation |
| # and/or other materials provided with the distribution. |
| # * Neither the name of the Ruby FFI project nor the names of its contributors |
| # may be used to endorse or promote products derived from this software |
| # without specific prior written permission. |
| # |
| # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| # DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE |
| # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| # SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| module FFI |
| # |
| # FFI::ManagedStruct allows custom garbage-collection of your FFI::Structs. |
| # |
| # The typical use case would be when interacting with a library |
| # that has a nontrivial memory management design, such as a linked |
| # list or a binary tree. |
| # |
| # When the {Struct} instance is garbage collected, FFI::ManagedStruct will |
| # invoke the class's release() method during object finalization. |
| # |
| # @example Example usage: |
| # module MyLibrary |
| # ffi_lib "libmylibrary" |
| # attach_function :new_dlist, [], :pointer |
| # attach_function :destroy_dlist, [:pointer], :void |
| # end |
| # |
| # class DoublyLinkedList < FFI::ManagedStruct |
| # @@@ |
| # struct do |s| |
| # s.name 'struct dlist' |
| # s.include 'dlist.h' |
| # s.field :head, :pointer |
| # s.field :tail, :pointer |
| # end |
| # @@@ |
| # |
| # def self.release ptr |
| # MyLibrary.destroy_dlist(ptr) |
| # end |
| # end |
| # |
| # begin |
| # ptr = DoublyLinkedList.new(MyLibrary.new_dlist) |
| # # do something with the list |
| # end |
| # # struct is out of scope, and will be GC'd using DoublyLinkedList#release |
| # |
| # |
| class ManagedStruct < FFI::Struct |
| |
| # @overload initialize(pointer) |
| # @param [Pointer] pointer |
| # Create a new ManagedStruct which will invoke the class method #release on |
| # @overload initialize |
| # A new instance of FFI::ManagedStruct. |
| def initialize(pointer=nil) |
| raise NoMethodError, "release() not implemented for class #{self}" unless self.class.respond_to? :release |
| raise ArgumentError, "Must supply a pointer to memory for the Struct" unless pointer |
| super AutoPointer.new(pointer, self.class.method(:release)) |
| end |
| |
| end |
| end |