Parent

Methods

FFI::ManagedStruct

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 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

Public Class Methods

new click to toggle source

When passed a pointer, create a new ManagedStruct which will invoke the class method release() on

    # File lib/ffi/managedstruct.rb, line 48
48:     def initialize(pointer=nil)
49:       raise NoMethodError, "release() not implemented for class #{self}" unless self.class.respond_to? :release
50:       raise ArgumentError, "Must supply a pointer to memory for the Struct" unless pointer
51:       super FFI::AutoPointer.new(pointer, self.class.method(:release))
52:     end

Disabled; run with --debug to generate this.

[Validate]

Generated with the Darkfish Rdoc Generator 1.1.6.