Count the number of cleanups performed, in stats

When running a busy ccache, it is useful to keep track of the number
of cleanups performed to know when you need to increase the cache size.

The number shown is actually the number of subdirectories, so when
you do a full cleanup the counter usually increases by 16 (not just 1).

1 files changed, 20 insertions, 0 deletions

diff --git a/stats.c b/stats.c
index 5f217657..e9a8f09e 100644
--- a/stats.c
+++ b/stats.c
@@ -78,6 +78,7 @@ static struct {
 	{ STATS_DEVICE,       "output to a non-regular file   ", NULL, 0 },
 	{ STATS_NOINPUT,      "no input file                  ", NULL, 0 },
 	{ STATS_BADEXTRAFILE, "error hashing extra file       ", NULL, 0 },
+	{ STATS_NUMCLEANUPS,  "cleanups performed             ", NULL, FLAG_ALWAYS },
 	{ STATS_NUMFILES,     "files in cache                 ", NULL,
 		FLAG_NOZERO|FLAG_ALWAYS },
 	{ STATS_TOTALSIZE,    "cache size                     ",
@@ -407,3 +408,22 @@ stats_set_sizes(const char *dir, unsigned num_files, uint64_t total_size)
 	free(statsfile);
 	counters_free(counters);
 }
+
+/* count directory cleanup run */
+void
+stats_add_cleanup(const char *dir, unsigned count)
+{
+	struct counters *counters = counters_init(STATS_END);
+	char *statsfile;
+
+	statsfile = format("%s/stats", dir);
+
+	if (lockfile_acquire(statsfile, lock_staleness_limit)) {
+		stats_read(statsfile, counters);
+		counters->data[STATS_NUMCLEANUPS] += count;
+		stats_write(statsfile, counters);
+		lockfile_release(statsfile);
+	}
+	free(statsfile);
+	counters_free(counters);
+}