I'm thinking perhaps we should instead pass a const pointer to:
typedef struct {
TSReturnCode (*globalArgIndexReserve)(const char * name, const char *
description, int * arg_idx);
TSReturnCode (*globalArgIndexNameLookup)(const char * name, int *
arg__idx, const char ** description);
TSReturnCode (*globalArgIndexLookup)(int arg_idx, const char ** name,
const char ** description);
void (*globalArgSet)(TSHttpTxn txnp, int arg_idx, void * arg);
} TSCallInPluginInitFuncs;
to TSPluginInit() (new parameter), and only define one new TS API function
(the get function). More idiot proof.
Would it trigger an assert if arg set was called more than once for a
particular index? Do we need both a Reserve and a NameLookup, can't the
lookup create the index if it doesn't exist?
On Thu, Feb 27, 2020 at 11:13 AM Leif Hedstrom <zw...@apache.org> wrote:
> Hi all,
>
> This is an idea from Bryan Call, which he suggested as a solution for
> reloadable plugins changes that are now in 9.0.x. I recently ran into a
> different use case (thanks Miles …), which could really benefit
> (performance wise) with such APIs. I *could* use the TxnArg APIs instead,
> but these new global arg APIs would make it noticeable faster (and less
> locking). So, I’m writing up this proposal based on these ideas, for
> discussion / adjustments.
>
> First off, I’m modeling these completely after the existing ConnArg /
> SsnArg / TxnArg, with the exception that they won’t have a limit on the
> number of slots (why bother?).
>
> TSReturnCode TSGlobalArgIndexReserve(const char * name, const char *
> description, int * arg_idx)
> TSReturnCode TSGlobalArgIndexNameLookup(const char * name, int *
> arg__idx, const char ** description)
> TSReturnCode TSGlobalArgIndexLookup(int arg_idx, const char ** name,
> const char ** description)
> void TSGlobalArgSet(TSHttpTxn txnp, int arg_idx, void * arg)
> void * TSGlobalArgGet(TSHttpTxn txnp, int arg_idx)
>
> I’m thinking a simple std::vector here (with a lock for good measure) for
> reserving and looking up slots by name. As for lookup performance, I don’t
> think this is a problem though, I imagine the use case here is to call
> TSGlobalArgIndexReserve() and TSGlobalArgIndexNameLookup() in the Init()
> functions of plugins that need access to a global slot, and from thereon
> use the index only. The vector will simply store a void*, the name and
> description.
>
> And discuss.
>
> — Leif
>
>
