Add signature file for VBA projects (2nd try)

[HolgiHo]

PR for issue #411, 2nd try.

Library changes:

• workbook: new API function workbook_add_vba_project_signature
• packager: copy vbaProjectSignature.bin, create vbaProject.bin.rels

Tests:

• new functional test test_macro_signed

Examples:

• add examples/macro_signed.c
• fix examples/vbaProject.bin: Was corrupted; now the button press works again; VBA project is signed by "VBA Code Signing"
• add examples/vbaProjectSignature.bin: The digitial signature, based on "VBA Code Signing" certificate

Utilities for testing the VBA project is signed correctly:

• new directory dev/vba_code_signing containing:
  • the "VBA Code Signing" certificate certificate.pfx that was used to sign the VBA project file. This certificate is self-signed and only for testing purposes. The password for the private key is "xlsxwriter". In reality, you would obtain a code signing certificate from an offical Certificate Authority. This process is usually quite complex and expensive.
  • PowerShell scripts for creating, exporting, and importing VBA code signing certificates. Execute import_certificate.ps1 to install certificate.pfx on your computer to test the example VBA project is actually signed in Excel.

[jmcnamara]

Moving comments to new PR.

I think a better function name would be workbook_add_signed_vba_project_signature(lxw_workbook self, const char vba_project, const char *signature).

Do you mean workbook_add_signed_vba_project (without "signature)?

Yes. workbook_add_signed_vba_project(lxw_workbook *self, const char *vba_project, const char *signature)

[HolgiHo]

Hi, what about the falling jobs? Is there a misconfiguration of the container used for the workflows?

[jmcnamara]

Thanks. The latest changes look good.

Let's deal with the PRs one at a time so that there isn't overlapping emails:

1. libxlsxwriter VBA code signing
2. libxlsxwriter const *char issues
3. libxlsxwriter ctest/unit test issues
4. XlsxWriter VBA code signing

For this PR could you do the following:

• [ ] Omit the dev/code_signing directory. We can add it to the Python library instead.
• [ ] Rebase the commits into one (if you know how to do that, if not I can do it on merge)

Note, the Valgrind CI test is failing but I think that is due to some changes in the GitHub Actions backend. I'll look into that separately.

[jmcnamara]

Note, there is some trailing whitespace in places not covered by the indent check. Could you remove those from the commit.

[jmcnamara]

Hi, what about the falling jobs? Is there a misconfiguration of the container used for the workflows?

Don't worry about it. It is just something that has changed in the CI container. It was working last week and nothing in your PR would affect it. It happens periodically. I'll look into it separately.

[HolgiHo]

Note, there is some trailing whitespace in places not covered by the indent check. Could you remove those from the commit.

Could you provide a hint where you found them? Also including the locations in the indent check would be a good idea ;-)

[jmcnamara]

Could you provide a hint where you found them?

I just did a git show on the commit. I have the color.ui=auto option turned on so it shows trailing whitespace with a bright red square.

Also including the locations in the indent check would be a good idea ;-)

The trailing whitespaces are in the dox files and in the examples (which aren't checked/formatted by default to allow for some additional non-automatic formatting for instruction purposes).

I normally configure my editor(s) to remove trailing whitespace on save.

[HolgiHo]

Believe it or not, VS has no option to delete trailing spaces :-( There is a plugin, but it isn't compatible with VS 2022.

I know how to squash multiple commits into one in a git repo, but what I don't know is: Do I need a new PR for this? I think I even need to create a new branch on the remote (or delete and re-create it), right?

[HolgiHo]

Btw. if (!workbook->vba_project) isn't even necessary anymore in packager.c. workbook_add_signed_vba_project will never set workbook->vba_project_signature when workbook->vba_project is not set, so the test is redundant.

[jmcnamara]

Merged. Thanks.