WindowsCOM

Ruby FFI (x86) bindings to essential COM related Windows APIs

• convenient DSL for binding COM interface definitions

IUIFramework = COMInterface[IUnknown,
  'F4F0385D-6872-43a8-AD09-4C339CB3F5C5',

  Initialize: [[:pointer, :pointer], :long],
  Destroy: [[], :long],
  LoadUI: [[:pointer, :buffer_in], :long],
  GetView: [[:uint, :pointer, :pointer], :long],
  GetUICommandProperty: [[:uint, :pointer, :pointer], :long],
  SetUICommandProperty: [[:uint, :pointer, :pointer], :long],
  InvalidateUICommand: [[:uint, :int, :pointer], :long],
  FlushPendingInvalidations: [[], :long],
  SetModes: [[:int], :long]
]

UIFramework = COMFactory[IUIFramework, '926749fa-2615-4987-8845-c33e65f2b957']

IUIApplication = COMInterface[IUnknown,
  'D428903C-729A-491d-910D-682A08FF2522',

  OnViewChanged: [[:uint, :int, :pointer, :int, :int], :long],
  OnCreateUICommand: [[:uint, :int, :pointer], :long],
  OnDestroyUICommand: [[:uint, :int, :pointer], :long]
]

IUIApplicationImpl = COMCallback[IUIApplication]

• straightforward usage of the resulting Ruby classes

class UIA < IUIApplicationImpl
  # uich is an instance of IUICommandHandlerImpl subclass (bindings and definition omitted for brevity)
  def initialize(uich)
    @uich = uich

    super() # wire COM stuff
  end

  attr_reader :uich

  # COM interface method implementations

  def OnCreateUICommand(*args)
    uich.QueryInterface(uich.class::IID, args[-1])

    S_OK
  end
end

uif = UIFramework.new # system COM object implementing the IUIFramework interface
uia = UIA.new(uich) # Ruby COM object implementing the IUIApplication interface

• transparent interop with code expecting COM interface pointers

uif.Initialize(hwnd, uia)

Classes starting with capital I are wrappers around raw COM interface pointers inheriting from COMInterface_ (e.g. IUIApplication). They contain COMVptr_ and COMVtbl_ (FFI::Struct implementations) instances wired to the corresponding COM interface implementation base and virtual table pointers and are (usually) not directly instantiated by application code.

Classes not starting with capital I are COM factories (obtain COM interface implementations using CoCreateInstance) inheriting from the corresponding COM interface class (e.g. UIFramework is a factory for creating instances of IUIFramework). They are directly instantiated by application code and create system COM objects implementing the corresponding interface.

Classes starting with capital I and ending with Impl are COM callbacks inheriting from the corresponding COM interface class (e.g. IUIApplicationImpl is a base class for implementing the IUIApplication interface in Ruby). They are usually subclassed, implement (some) of the corresponding COM interface methods and then instantiated by application code.

All kinds of classes can be freely subclassed and used regardless of their COM duties (just don't forget to call super appropriately in the subclass #initialize method). COMInterface_ (their common base) implements #to_ptr (returning the corresponding COMVptr_ instance pointer), so the instances can be directly passed to code expecting COM interface pointers. In a scenario where the COM stuff is used as instance variables of some other class, but it is desirable for the class instances to be passed transparently to code expecting COM interface pointers, just define #to_ptr calling the appropriate COM object #to_ptr.

gem install windows_com

See examples folder (the UIRibbon example requires windows_gui gem)