Re: [Tarantool-patches] [PATCH v3 1/4] vclock: add an ability to set individual clock components

[Konstantin Osipov <kostja.osipov@gmail.com>]

* Serge Petrenko <sergepetrenko@tarantool.org> [20/03/23 19:23]:
> This is needed to 'hide' 0-th vclock component in replication responses.

I think the name should reflect the magic that happens in this
function.

How about vclock_reset()?

> 
> Follow-up #3186
> Prerequisite #4114
> ---
>  src/box/vclock.c | 15 +++++++++++++++
>  src/box/vclock.h | 11 +++++++++++
>  2 files changed, 26 insertions(+)
> 
> diff --git a/src/box/vclock.c b/src/box/vclock.c
> index 90ae27591..302c0438d 100644
> --- a/src/box/vclock.c
> +++ b/src/box/vclock.c
> @@ -37,6 +37,21 @@
>  #include "diag.h"
>  #include "tt_static.h"
>  
> +void
> +vclock_set(struct vclock *vclock, uint32_t replica_id, int64_t lsn)
> +{
> +	assert(lsn >= 0);
> +	assert(replica_id < VCLOCK_MAX);
> +	vclock->signature -= vclock_get(vclock, replica_id);
> +	if (lsn == 0) {
> +		vclock->map &= ~(1 << replica_id);
> +		return;
> +	}

> +	vclock->lsn[replica_id] = lsn;
> +	vclock->map |= 1 << replica_id;
> +	vclock->signature += lsn;
> +}
> +
>  int64_t
>  vclock_follow(struct vclock *vclock, uint32_t replica_id, int64_t lsn)
>  {
> diff --git a/src/box/vclock.h b/src/box/vclock.h
> index 79e5a1bc0..7dc69015f 100644
> --- a/src/box/vclock.h
> +++ b/src/box/vclock.h
> @@ -211,6 +211,17 @@ vclock_calc_sum(const struct vclock *vclock)
>  	return sum;
>  }
>  
> +/**
> + * Set vclock component represented by replica id to the desired
> + * value.

Why is it necessary and how is it used? Should be in this comment. 
The use case is still not very clear from the commit comment.

> + *
> + * @param vclock Vector clock.
> + * @param replica_id Replica identifier.
> + * @param lsn Lsn to set
> + */
> +void
> +vclock_set(struct vclock *vclock, uint32_t replica_id, int64_t lsn);
> +
>  static inline int64_t
>  vclock_sum(const struct vclock *vclock)

-- 
Konstantin Osipov, Moscow, Russia
https://scylladb.com