[Python-Dev] Exposing the Android platform existence to Python modules

[Shiz]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

Charles-François Natali wrote:
> Well, Android is so popular that supporting it would definitely be
> interesting. There are a couple questions however (I'm not familiar
> at all with Android, I don't have a smartphone ;-): - Do you have an
> idea of the amount of work/patch size required? Do you have an
> example of a patch (even if it's a work-in-progess)? - Is there
> really a common Android platform? I've heard a lot about 
> fragmentation, so would we have to support several Android flavours 
> (like #ifdef __ANDROID_VENDOR_A__, #elif defined 
> __ANDROID_VENDOR_B__)?

Absolutely! I maintain a public repository of patches against CPython
v3.3.3 at [1].

They are divided into three large patches: one fixes some issues I
encountered with CPython's build system for cross-compilation, one fixes
Android/Bionic's numerous locale issues (locale.h/langinfo.h support in
Android is basically a set of stub functions that return NULL), and the
last one is a set of 'misc' fixes for things that affect Android, mainly
smaller things like missing fields in struct passwd and the like.

With those patches, CPython 3.3.3 will cross-compile to and run on at
least my own Android device, a Moto G running Android 4.4.2. What's left
to fail is fix the numerous regression test failures and their causes. I
documented some of my findings at [2]. :)

As far as Android fragmentation goes, to my knowledge that mainly refers
to fragmentation at two levels: the Android versions numerous devices
run tends to differ greatly, and the screen sizes, resolutions and
aspect ratios vary greatly. Obviously the latter is a problem beyond the
scope of CPython, but the former could lead to some issues.

Luckily however, the NDK[3], the SDK of choice to use for C/C++-level
applications, is fairly unified and expected to be used for pretty much
all Android devices. Essentially there should be only the NDK for
CPython to target, with a variety of NDK versions to support depending
on which versions of Android CPython chooses to support. So far I've
been only testing against NDK r9c, so I'm honestly not all that familiar
with the changes different NDK versions bring, but from what I heard up
until NDK r10 were mostly toolchain updates and header additions for new
Android versions.

I'd dare say that the vast, vast majority of Android devices out there
are running on the same base, namely AOSP[4] with numerous vendor
fixes/drivers/additions, and that custom Android distributions would try
not to break NDK compatibility.

Kind regards,
Shiz

[1]: https://github.com/rave-engine/python3-android/tree/master/src
[2]: https://github.com/rave-engine/python3-android/issues/3
[3]: https://developer.android.com/tools/sdk/ndk/index.html
[4]: https://source.android.com/
-----BEGIN PGP SIGNATURE-----
Version: GnuPG/MacGPG2 v2.0.22 (Darwin)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
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=
=pMFQ
-----END PGP SIGNATURE-----