I’d like to add this new TS API:
/**
Check to see if an MBuffer is still valid, from since the time
it was acquired.
*/
bool TSMBufferIsValid(TSMBuffer bufp);
The intent of this API is to check if a TSMbuffer, and any pointers related to
this buffer, are still valid. Why would they not be, you ask? There are cases
where these heap buffers are coalesced, and when that happens, the pointers you
may have fetched earlier, are no longer valid.
Today, there’s no way to know if your pointers and buffers are valid, The new
API, and the changes to the core and APIs it comes with, allows a plugin, or a
plugin framework such as txn_box, to verify that saved (or cached) pointers are
still valid. For Cripts, it has to invalidate all saved pointers between every
hook, even though more often than not, it could have kept them (they are stored
and saved in a transaction context).
With this addition, Cripts (and txn_box) could keep values around for much
longer, and check with this new API if these cached pointers are still valid.
I’d imagine similar optimizations could now be added to e.g. header_rewrite and
other plugins as well (keeping state between hooks). The proposed API, and
changes are in this PR:
https://github.com/apache/trafficserver/pull/11780
Thanks,
— Leif
