Patch to support xNVMe

[Baekalfen]

Hi, I used autopxd over at xNVMe, and needed to patch a few things to make it work, and I thought it could be of use to others.

The commits should be self-contained and have each the functionality they describe.

An overview:

• --regex on command-line to allow arbitrary conversions. Some datatypes or syntax just doesn't get parsed correctly by autopxd. As a quick solution, I can hotfix something easily without making full and proper support in autopxd -- for example an opaque pointer in a function I don't need. (--regex 's/FILE \*/void */g').
• Flattening members of unnamed unions and structs. Cython just cannot express these, so I made a "hack" where these members become accessible at least in some manner. See example below.
• Make enums into cpdef to make them accessible from Python as well as Cython for free.
• Ignore StaticAssert. Simply skip them. They don't make much sense in Cython and currently it makes autopxd output faulty code.
• Possible to ignore known/defined declarations. Maybe there's a better way to do this, but I needed this to support multiple .h files. This way, I can provide the declarations from other headers, so they are not repeated. There is a better way. The whitelist kwarg.
• Replace wget in favor of urllib. Not all distros has wget (nor cURL) installed, so I opted for a native Python implementation. This works across all distros I have tried (xNVMe test run).

I would love to get feedback from you, especially on the part I will highlight.

struct test_struct {
    int a;
    struct {
        int b;
        int c;
    }
}

cdef struct test_struct:
    int a
    int b
    int c

[Baekalfen]

I would love to hear, if there's a better way to do this.

[elijahr]

@Baekalfen this is great! Can you get tests passing?

[Baekalfen]

@Baekalfen this is great! Can you get tests passing?

Yes, I'll get it fixed. I realize the thing with anon nested structs (like below) isn't totally correct. I'll investigate further if it needs to be narrowed down or removed.

    int nested__d
    int nested__e

[Baekalfen]

They should be fixed now to get the best of both worlds. The confusing came from trying to print the structs.

This will work for any struct as long as it only has named nested structs inside it.

cdef test_struct A = ...
A.nested.x = 2
print(A)

But the same setup with a struct that contains a nested anon struct will result in a compile error along the lines of:

test_cython.c:4240:18: error: conflicting types for '__pyx_convert__to_py_struct___xnvme_opts_css'
static PyObject* __pyx_convert__to_py_struct___xnvme_opts_css(struct _xnvme_opts_css s) {

But dropping the print of the entire struct, will make it work. I believe this is either a bug in Cython or an accepted limitation from their side.

cdef test_struct A = ...
A.nested.x = 2
print(A.a)
print(A.b)
print(A.c)
print(A.nested.x)

[Baekalfen]

@elijahr The tests and the formatting should all be done now, but there's something with the linting step in GHA.

[Baekalfen]

I removed the additional ignore thing. Using the whitelist kwarg was much easier once I got it to work. I think the docs are a little off. You have to add '<stdin>' to the whitelist to allow declarations from the .h file you are providing. Otherwise it only takes declarations from the whitelisted includes.

[elijahr]

This is great! Thanks so much for the contribution!

[elijahr]

@Baekalfen this has been released in https://pypi.org/project/autopxd2/2.1.1/

[Baekalfen]

@Baekalfen this has been released in https://pypi.org/project/autopxd2/2.1.1/

Fantastic! Thank you!