s3-printing: Add method to skip refresh if just happned.

This way if multiple process try to refresh at the same time we don't do it
over and over again.

Signed-off-by: Andreas Schneider <asn@cynapses.org>

3 files changed, 34 insertions, 0 deletions

diff --git a/source3/printing/pcap.c b/source3/printing/pcap.c
index 2e544b7cdc3..3bc8e9e4e29 100644
--- a/source3/printing/pcap.c
+++ b/source3/printing/pcap.c
@@ -121,6 +121,12 @@ void pcap_cache_reload(struct tevent_context *ev,
 		return;
 	}
 
+	if (!printer_list_need_refresh()) {
+		/* has been just refeshed, skip */
+		DEBUG(5, ("Refresh just happend, skipping.\n"));
+		return;
+	}
+
 	status = printer_list_mark_reload();
 	if (!NT_STATUS_IS_OK(status)) {
 		DEBUG(0, ("Failed to mark printer list for reload!\n"));
diff --git a/source3/printing/printer_list.c b/source3/printing/printer_list.c
index 123749cf46f..6392755cf5a 100644
--- a/source3/printing/printer_list.c
+++ b/source3/printing/printer_list.c
@@ -215,6 +215,32 @@ done:
 	return status;
 }
 
+bool printer_list_need_refresh(void)
+{
+	NTSTATUS status;
+	time_t now = time(NULL);
+	time_t last_refresh;
+
+	status = printer_list_get_last_refresh(&last_refresh);
+	if (!NT_STATUS_IS_OK(status)) {
+		return true;
+	}
+
+	if (now > last_refresh) {
+		/* if refresh occurred last than 1 seconds ago,
+		 * then we probably don't need to refresh */
+		if ((now - last_refresh) < 1) {
+			return false;
+		}
+	} else {
+		/* last_refresh newer than now, wow, someone just updated the
+		 * cache under our nose, do not do again. */
+		return false;
+	}
+
+	return true;
+}
+
 NTSTATUS printer_list_mark_reload(void)
 {
 	struct db_context *db;
diff --git a/source3/printing/printer_list.h b/source3/printing/printer_list.h
index 5772fbaaa33..a5e7993ed09 100644
--- a/source3/printing/printer_list.h
+++ b/source3/printing/printer_list.h
@@ -39,4 +39,6 @@ NTSTATUS printer_list_clean_old(void);
 NTSTATUS printer_list_run_fn(void (*fn)(const char *, const char *, void *),
 			     void *private_data);
 
+bool printer_list_need_refresh(void);
+
 #endif /* _PRINTER_LIST_H_ */