[Discussion] Should we free TEXT?

[Sunbreak]

https://github.com/timsneath/win32/blob/cc4870102e95b0c2cf0f4ca31e15baa1f783fe9e/lib/src/utils.dart#L22

TEXT uses toNativeUtf16, which uses allocator

https://github.com/dart-lang/ffi/blob/24eb0a066d3b32e54682a57e4780af4e2efbd2d3/lib/src/utf16.dart#L76-L83

  Pointer<Utf16> toNativeUtf16({Allocator allocator = malloc}) {
    final units = codeUnits;
    final Pointer<Uint16> result = allocator<Uint16>(units.length + 1);
    final Uint16List nativeString = result.asTypedList(units.length + 1);
    nativeString.setRange(0, units.length, units);
    nativeString[units.length] = 0;
    return result.cast();
  }

But code in samples doesn't take care of free

https://github.com/timsneath/win32/blob/cc4870102e95b0c2cf0f4ca31e15baa1f783fe9e/example/hello.dart#L41

Related: dart-archive/ffi#86

[timsneath]

Yes, you absolutely should. Sorry -- some of my samples are very shoddy in this regard, since they're short lived and the process will free up the memory on exit. I've gradually moved some of them over to use a try... finally block, but I should fix up the rest.

[timsneath]

I've made a number of fixes to this in the short term. As you say, it's important to do this in production code, but it makes some of the samples rather painful to read because of all the allocation / deallocation. Ultimately I'd like to fix this by using the Pool feature so that these are automatically deallocated when they fall out of scope.

[Sunbreak]

BTW, should we free Pointer<COMObject> in object from CoCreateInstance ?

https://github.com/timsneath/win32/blob/a608e2e47c8c6f2cc94180b4de101592b308a54c/example/wmi.dart#L43-L57

if (FAILED(hr)) {
  // ...
  free(pLoc.ptr);
  CoUninitialize();
  throw exception; 
}

[timsneath]

I think I've fixed all instances of this; please reopen if you find any further leaks.