Questions on possible changes to be performed

Hi, I’m opening this issue because, while libaums fulfills most of my needs for EtchDroid, there are currently a few issues which are forcing me to keep my incompatible fork, and I’d reeeeally like to avoid that.

So these are a few changes I’d like to merge here, let me know what you think about them and what kind of changes you would like.

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First of all, and we already talked about this, I’d need to access the block device directly. In my fork I made blockDevice public:

https://github.com/EtchDroid/libdepaums/blob/master/libdepaums/src/main/java/eu/depau/etchdroid/libdepaums/UsbMassStorageDevice.kt#L106

I remember you rejected my PR for this because I didn’t have any tests written. Before you ask: no, I’m not planning to write unit tests for the SCSI protocol 😂

It should probably be better to write instrumented tests for that instead of unit tests. And by the way I’m planning to do that! I’m working on a Qemu setup with Android-x86 that emulates a USB 3.0 stick, it works-ish but I need to get some issues fixed.

Other than that it’s just a matter of running qemu with:

  -device nec-usb-xhci,id=xhci \
  -drive if=none,id=usbstick,file=usb.img,format=raw \
  -device usb-storage,bus=xhci.0,drive=usbstick

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(Pretty easy to merge if above also gets merged)

I wrote InputStream and OutputStream implementations on top of BlockDeviceDrivers:

https://github.com/EtchDroid/libdepaums/tree/master/libdepaums/src/main/java/eu/depau/etchdroid/libdepaums/streams

With tests:

https://github.com/EtchDroid/libdepaums/tree/master/libdepaums/src/test/java/eu/depau/etchdroid/libdepaums/streams

The use case is simply to be able to copy data in a dd kinf of fashion, which is what EtchDroid does. Having a wrapper that implements a standard Java interface makes it easy for me to reuse code and provide the same kind of functionality on top of other implementations.

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(Breaks API)

I don’t necessarily need to access the filesystem inside of the USB drive, the fact that by default it reads the partition table kind of gets in my way, so I had to incompatibly split that away:

https://github.com/EtchDroid/libdepaums/blob/dafec1f38fd2028bd983cc570d4dbf7efbbd3d85/libdepaums/src/main/java/eu/depau/etchdroid/libdepaums/UsbMassStorageDevice.kt#L124-L194

While this is a deal-breaker for me, I could probably be able to keep a soft-fork if you’d prefer not to break the API. Or if you have a better solution that doesn’t break the API I’ll be happy to adopt it.

Let me know 😃

[depau]

Alright, I will send you a pull request soon™️ 😉

[magnusja]

This would change the API but it would be perfectly backwards compatible, so that would be fine for me 😃