Add a helper function to check if an extension is supported by file transform

[meimchu]

resolves #1938 issue. Please let me know if this is what Doug is looking for!
My plan:

• Write the function
• Write C++ tests
• Write python binding
• Write python tests

(Hope my auto whitespace cleanup is ok. I recognize it can make the git history slightly more dirty.)

[meimchu]

For the python side, I have a question about the python binding as I am not very familiar with pybind11 yet. I was testing with the following in PyFileTransform.cpp. I assumed that it is defining a python function that calls on FileTransform::IsFormatExtensionSupported and passing the extension argument.

.def("IsFormatExtensionSupported", &FileTransform::IsFormatExtensionSupported, "extension"
    DOC(FileTransform, IsFormatExtensionSupported));

However, I get a this error when trying to build about wrong argument counts. Any help and pointer about this is greatly appreciated.

error: static assertion failed due to requirement 'expected_num_args<pybind11::name, pybind11::is_method, pybind11::sibling, pybind11::arg, const char *>(sizeof...(Args), argument_loader<const char *>::args_pos >= 0, argument_loader<const char *>::has_kwargs)': The number of argument annotations does not match the number of function arguments

[doug-walker]

Thanks Mei, this looks great!

For the Python binding, please try this:

.def_static("IsFormatExtensionSupported", &FileTransform::IsFormatExtensionSupported, "extension"_a,
    DOC(FileTransform, IsFormatExtensionSupported))

(And add a semi-colon if it's the last one.)

Regarding the white space clean-up, let's bring this up at the TSC meeting to see if people object to that.

[remia]

Thank you @meimchu, for the white space changes, it needs to be in separated commit(s) and those listed in a .git-blame-ignore-revs at the root of OpenColorIO folder like described here. I started looking at clang-format last week, so I might make a PR for that later as well, that would only cover the C++ files though.

[remia]

Suggest to also protect against invalid pointer:

if (!extension || !*extension)
{
    return false;
}

[meimchu]

I have added those conditions for early return.

[meimchu]

I have also reverted all the whitespaces removed as part of my initial commits.

[doug-walker]

LGTM!