Fix #224: Add a clang-format that matches the best the OpenSSL coding style.

[thb-sb]

This commit adds a .clang-format file at the root of the repository. This .clang-format file tries to match the best the OpenSSL coding style.

This commit also reformats the existing code according to that .clang-format.

Finally, it adds a new CircleCI job to ensure that the code is well-formatted.

[thb-sb]

@baentsch , CI jobs are failing because of the generated code that get reformat by clang-format.

Should we add a "post-step" to the code generation job, where we run clang-format?

[baentsch]

Should we add a "post-step" to the code generation job, where we run clang-format?

Yes -- that would be easier than getting all "jinja2" magic to align (particularly considering #228). I started to look into that when evaluating the impact of #224 but hit some clang version dependency: Is it possible that clang-format is dependent on clang version used? If so I think we also should be explicit in the build env which clang version to use.

[thb-sb]

Yes -- that would be easier than getting all "jinja2" magic to align (particularly considering #228).

👍 , will do that.

Is it possible that clang-format is dependent on clang version used? If so I think we also should be explicit in the build env which clang version to use.

It is indeed: some clang-format directives are new and may be unavailable in older versions.
Basically, versions of clang-format follow clang's.

I checked the .clang-format I suggest, and the PPIndentWidth directive is the "latest" one, because it requires clang-13, and LLVM 13 was released in October 2021. Otherwise, the second most "latest" one requires clang-11.

[baentsch]

because it requires clang-13

I'd be fine mandating that for a build env. The OQS main CI build env is "Ubuntu Jammy" -- and that's at clang-14 if I'm not mistaken.

[thb-sb]

I'd be fine mandating that for a build env. The OQS main CI build env is "Ubuntu Jammy" -- and that's at clang-14 if I'm not mistaken.

Exactly.

I've updated the CircleCI job to use clang-14 from "Ubuntu Jammy".
I had to disable PPIndentWidth because it seems broken in 14 but fixed in 15. So we won't be able to enforce the following:

Pre-processor directives use one space for indents:

[baentsch]

So we won't be able to enforce the following:

Pre-processor directives use one space for indents:

Tough luck.

[baentsch]

In general, very good: Looks like OpenSSL code. In most areas formatting (and readability) improved; in some it really became awful (see single comments): Is there something that could be done about those? OK, it's generated code, but still, it should be somewhat legible to humans, no?

[thb-sb]

Is there something that could be done about those? OK, it's generated code, but still, it should be somewhat legible to humans, no?

I agree. We can disable clang-format for some portions of the code.
Let me try something about this generated code.

[thb-sb]

@baentsch when I run the generate.py script, I got a diff on ALGORITHMS.md and on other files:

@@ -34,8 +34,6 @@ As standardization for these algorithms 
 | kyber768 | 0x023C | Yes | OQS_CODEPOINT_KYBER768 |
 | p384_kyber768 | 0x2F3C | Yes | OQS_CODEPOINT_P384_KYBER768 |
 | x448_kyber768 | 0x2F90 | Yes | OQS_CODEPOINT_X448_KYBER768 |
-| x25519_kyber768 | 0x6399 | Yes | OQS_CODEPOINT_X25519_KYBER768 |
-| p256_kyber768 | 0x639A | Yes | OQS_CODEPOINT_P256_KYBER768 |
 | kyber1024 | 0x023D | Yes | OQS_CODEPOINT_KYBER1024 |
 | p521_kyber1024 | 0x2F3D | Yes | OQS_CODEPOINT_P521_KYBER1024 |
 | bikel1 | 0x0241 | Yes | OQS_CODEPOINT_BIKEL1 |

I did:

$ OQS_ALGS_ENABLED=STD LIBOQS_SRC_DIR=../liboqs python3 oqs-template/generate.py

I tried without OQS_ALGS_ENABLED and I get the same. My liboqs is on main.
Do you have any idea why?

Edit: running the script on linux is fine, but not on macOS.

[thb-sb]

I added a // clang-format off / // clang-format on surrounding the oqsprov.c/kem_functions.fragment file. It should fix your two comments about the weird indentation of KEMHYBALGs.

I also removed the // #include "internal/cryptlib.h".

289bff8

[baentsch]

Do you have any idea why?

Not really -- this is (should be) all driven off "generate.yml".

Edit: running the script on linux is fine, but not on macOS.

Are you sure "generate.yml" is identical on both machines? I just ran the script on macOS and nothing changed (i.e., x25519_kyber768 and p256_kyber768 "persisted").

[thb-sb]

Are you sure "generate.yml" is identical on both machines? I just ran the script on macOS and nothing changed (i.e., x25519_kyber768 and p256_kyber768 "persisted").

OK, it must have been because now it works. Sorry for the noise…