From: Jeff Hostetler <jeffhostetler@xxxxxxxxxx>
Improve documentation of the refresh callback helper function
used for directory FSEvents.
Signed-off-by: Jeff Hostetler <jeffhostetler@xxxxxxxxxx>
---
fsmonitor.c | 37 ++++++++++++++++++++++++-------------
1 file changed, 24 insertions(+), 13 deletions(-)
diff --git a/fsmonitor.c b/fsmonitor.c
index 6fecae9aeb2..29cce32d81c 100644
--- a/fsmonitor.c
+++ b/fsmonitor.c
@@ -183,24 +183,35 @@ static int query_fsmonitor_hook(struct repository *r,
return result;
}
+/*
+ * 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).
+ */
static void handle_path_with_trailing_slash(
struct index_state *istate, const char *name, int pos)
{
int i;
- /*
- * 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;
--
gitgitgadget
