[Feature] use like function for temporory native malloc/calloc object

[Sunbreak]

It is quit easy to forget to free memory from toNativeUtf8 and toNativeUtf16

Sunbreak/logic_conf.dart@956ac5a

-    var descriptor = _libc.open2(path.toNativeUtf8().cast(), O_RDWR);
+    var nativeUtf8 = path.toNativeUtf8();
+    var descriptor = _libc.open2(nativeUtf8.cast(), O_RDWR);
+    malloc.free(nativeUtf8);

Could we have some Kolin's use-like statement?

https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/use.html

FileWriter("test.txt")
  .use { w -> w.write("something") }

Or similiar ones:

• Java's try-with-resource: https://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html
• C# using: https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/using-statement

[Sunbreak]

Related

• https://github.com/dart-lang/sdk/issues/32486
• dart:ffi GC finalizers dart-lang/sdk#35770

[dcharkes]

Hey, please take a look at the Pool: https://github.com/dart-lang/sdk/blob/master/samples/ffi/resource_management/pool_sample.dart#L24-L31

  // To ensure resources are freed, wrap them in a [using] call.
  using((Pool pool) {
    final p = pool<Int64>(2);

    // Do something with p.

    // p is automatically `free`d at the end of this scope.
  });

Your could would probably be something such as:

final descriptor = using((Pool pool) {
  final nativeUtf8 = path.toNativeUtf8(pool);
  return _libc.open2(nativeUtf8.cast(), O_RDWR);
}

Please let me know if you find that sample useful, I could merge it to this package.

[Sunbreak]

It helps a lot. Sunbreak/logic_conf.dart#8

I'll appreciate if we could merge Pool to package:ffi

[Fox32]

Done by #103?

[dcharkes]

Indeed.

[hacker1024]

Is this documented anywhere? I had to go searching through issues to find this feature. I didn't think to look at the API reference because the README points to another website.

Perhaps a brief overview of the features provided by this package could be added to the README?