Expose checksum from zip archive.

[mw-cwilcox]

I'm requesting an enhancement, to expose a checksum of the bundle data.

Motivation

My team is using CppMicroServices in deployment where DLLs may be loaded, unloaded, and reloaded through the process lifetime, and would like to utilize a checksum to know if a bundle has changed from a prior load. There is already a 'crc32' in the zip-data, so this seems straightforward to implement.

Approach

• ('miniz.c' provides 'struct mz_zip_archive_file_stat', which has-a 'mz_uint32 m_crc32;' and is always set in 'mz_zip_reader_file_stat')
• Add a new field to 'BundleResourceContainer::Stat', perhaps 'uint32_t crc32', or 'unsigned int checksum'; the field would be assigned by 'BundleResourceContainer::GetStat', which already has the value inside 'struct mz_zip_archive_file_stat'.
• Add a new getter to 'BundleResource', such as 'uint32_t GetCrc32() const;' or 'unsigned int GetChecksum() const;'.

Branch

I intend to prototype exactly what I described here on a fork in a feature branch.

[mw-cwilcox]

Here's what I was thinking, using 'uint32_t' for the type, and 'GetCrc32' for the method name.
development...mw-cwilcox:307-bundle-crc32

[ksubramz]

Thanks Charles. The motivation and the changes you made in your feature branch look fine to me. I am awaiting feedback from other core developers.

[jeffdiclemente]

@mw-cwilcox looks good to me. please go ahead and issue a PR to the CppMicroServices development branch.

If you could also add the contents of this issue as a RFC, using the process in https://github.com/CppMicroServices/rfcs, that would be very helpful.

Thanks!

[mw-cwilcox]

Krish and Jeff,

I've created the PR #308.

Let me know if you need any other information.

Thanks!

[jeffdiclemente]

Fixed in #308