Re: [PATCH 06/12] fsmonitor: clarify handling of directory events in callback
On Tue, Feb 13, 2024 at 08:52:15PM +0000, Jeff Hostetler via GitGitGadget wrote:
Show 49 quoted lines
> From: Jeff Hostetler <jeffhostetler@github.com>
>
> Signed-off-by: Jeff Hostetler <jeffhostetler@github.com>
> ---
> fsmonitor.c | 47 +++++++++++++++++++++++++++++++++--------------
> 1 file changed, 33 insertions(+), 14 deletions(-)
>
> diff --git a/fsmonitor.c b/fsmonitor.c
> index 614270fa5e8..754fe20cfd0 100644
> --- a/fsmonitor.c
> +++ b/fsmonitor.c
> @@ -219,24 +219,40 @@ static void fsmonitor_refresh_callback_unqualified(
> }
> }
>
> -static void fsmonitor_refresh_callback_slash(
> +/*
> + * The daemon can decorate directory events, such as a move or rename,
> + * by adding a trailing slash to the observed name. Use this to
> + * explicitly invalidate the entire cone under that directory.
> + *
> + * The daemon can only reliably do that if the OS FSEvent contains
> + * sufficient information in the event.
> + *
> + * macOS FSEvents have enough information.
> + *
> + * Other platforms may or may not be able to do it (and it might
> + * depend on the type of event (for example, a daemon could lstat() an
> + * observed pathname after a rename, but not after a delete)).
> + *
> + * If we find an exact match in the index for a path with a trailing
> + * slash, it means that we matched a sparse-index directory in a
> + * cone-mode sparse-checkout (since that's the only time we have
> + * directories in the index). We should never see this in practice
> + * (because sparse directories should not be present and therefore
> + * not generating FS events). Either way, we can treat them in the
> + * same way and just invalidate the cache-entry and the untracked
> + * cache (and in this case, the forward cache-entry scan won't find
> + * anything and it doesn't hurt to let it run).
> + *
> + * Return the number of cache-entries that we invalidated. We will
> + * use this later to determine if we need to attempt a second
> + * case-insensitive search.
> + */
> +static int fsmonitor_refresh_callback_slash(
> struct index_state *istate, const char *name, int len, int pos)
> {
> int i;
> + int nr_in_cone = 0;Should we return `size_t` instead of `int`?
Patrick
Show 31 quoted lines
> - /*
> - * The daemon can decorate directory events, such as
> - * moves or renames, with a trailing slash if the OS
> - * FS Event contains sufficient information, such as
> - * MacOS.
> - *
> - * Use this to invalidate the entire cone under that
> - * directory.
> - *
> - * We do not expect an exact match because the index
> - * does not normally contain directory entries, so we
> - * start at the insertion point and scan.
> - */
> if (pos < 0)
> pos = -pos - 1;
>
> @@ -245,7 +261,10 @@ static void fsmonitor_refresh_callback_slash(
> if (!starts_with(istate->cache[i]->name, name))
> break;
> istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
> + nr_in_cone++;
> }
> +
> + return nr_in_cone;
> }
>
> static void fsmonitor_refresh_callback(struct index_state *istate, char *name)
> --
> gitgitgadget
>
>
Patrick Steinhardt <ps@pks.im>