fsmonitor: enhance existing comments, clarify trivial response handling

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
pull/1232/head
Jeff Hostetler 6 months ago committed by Junio C Hamano
parent 715d08a9e5
commit 974c1b3987
  1. 64
      fsmonitor.c

@ -168,29 +168,15 @@ static int query_fsmonitor(int version, const char *last_update, struct strbuf *
if (result)
trace2_data_intmax("fsm_hook", NULL, "query/failed", result);
else {
else
trace2_data_intmax("fsm_hook", NULL, "query/response-length",
query_result->len);
if (fsmonitor_is_trivial_response(query_result))
trace2_data_intmax("fsm_hook", NULL,
"query/trivial-response", 1);
}
trace2_region_leave("fsm_hook", "query", NULL);
return result;
}
int fsmonitor_is_trivial_response(const struct strbuf *query_result)
{
static char trivial_response[3] = { '\0', '/', '\0' };
return query_result->len >= 3 &&
!memcmp(trivial_response,
&query_result->buf[query_result->len - 3], 3);
}
static void fsmonitor_refresh_callback(struct index_state *istate, char *name)
{
int i, len = strlen(name);
@ -238,6 +224,7 @@ void refresh_fsmonitor(struct index_state *istate)
struct strbuf last_update_token = STRBUF_INIT;
char *buf;
unsigned int i;
int is_trivial = 0;
if (!core_fsmonitor || istate->fsmonitor_has_run_once)
return;
@ -283,6 +270,7 @@ void refresh_fsmonitor(struct index_state *istate)
query_success = 0;
} else {
bol = last_update_token.len + 1;
is_trivial = query_result.buf[bol] == '/';
}
} else if (hook_version < 0) {
hook_version = HOOK_INTERFACE_VERSION1;
@ -294,16 +282,38 @@ void refresh_fsmonitor(struct index_state *istate)
if (hook_version == HOOK_INTERFACE_VERSION1) {
query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION1,
istate->fsmonitor_last_update, &query_result);
if (query_success)
is_trivial = query_result.buf[0] == '/';
}
if (is_trivial)
trace2_data_intmax("fsm_hook", NULL,
"query/trivial-response", 1);
trace_performance_since(last_update, "fsmonitor process '%s'", core_fsmonitor);
trace_printf_key(&trace_fsmonitor, "fsmonitor process '%s' returned %s",
core_fsmonitor, query_success ? "success" : "failure");
}
/* a fsmonitor process can return '/' to indicate all entries are invalid */
if (query_success && query_result.buf[bol] != '/') {
/* Mark all entries returned by the monitor as dirty */
/*
* The response from FSMonitor (excluding the header token) is
* either:
*
* [a] a (possibly empty) list of NUL delimited relative
* pathnames of changed paths. This list can contain
* files and directories. Directories have a trailing
* slash.
*
* [b] a single '/' to indicate the provider had no
* information and that we should consider everything
* invalid. We call this a trivial response.
*/
if (query_success && !is_trivial) {
/*
* Mark all pathnames returned by the monitor as dirty.
*
* This updates both the cache-entries and the untracked-cache.
*/
buf = query_result.buf;
for (i = bol; i < query_result.len; i++) {
if (buf[i] != '\0')
@ -318,11 +328,16 @@ void refresh_fsmonitor(struct index_state *istate)
if (istate->untracked)
istate->untracked->use_fsmonitor = 1;
} else {
/* We only want to run the post index changed hook if we've actually changed entries, so keep track
* if we actually changed entries or not */
/*
* We failed to get a response or received a trivial response,
* so invalidate everything.
*
* We only want to run the post index changed hook if
* we've actually changed entries, so keep track if we
* actually changed entries or not.
*/
int is_cache_changed = 0;
/* Mark all entries invalid */
for (i = 0; i < istate->cache_nr; i++) {
if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID) {
is_cache_changed = 1;
@ -330,7 +345,10 @@ void refresh_fsmonitor(struct index_state *istate)
}
}
/* If we're going to check every file, ensure we save the results */
/*
* If we're going to check every file, ensure we save
* the results.
*/
if (is_cache_changed)
istate->cache_changed |= FSMONITOR_CHANGED;

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