stats: Use function pointers in reporter objects

Currently case statements are used to select the right reporter
functions. This makes it difficult to add new reporter types,
especially if they are not going to reside in the same file.

This commit introduces per reporter function pointer for
open, close, send_count, and send_item. They are checked for
non-NULL before being called or skipped.

Sponsored-by: On-Waves ehf

2 files changed, 40 insertions, 25 deletions

diff --git a/include/osmocom/core/stats.h b/include/osmocom/core/stats.h
index 9ee9f106..beeee16e 100644
--- a/include/osmocom/core/stats.h
+++ b/include/osmocom/core/stats.h
@@ -23,6 +23,10 @@
 #include <osmocom/core/linuxlist.h>
 
 struct msgb;
+struct stat_item_group;
+struct stat_item_desc;
+struct rate_ctr_group;
+struct rate_ctr_desc;
 
 enum stats_reporter_type {
 	STATS_REPORTER_STATSD,
@@ -53,6 +57,16 @@ struct stats_reporter {
 	int agg_enabled;
 
 	struct llist_head list;
+	int (*open)(struct stats_reporter *srep);
+	int (*close)(struct stats_reporter *srep);
+	int (*send_counter)(struct stats_reporter *srep,
+		const struct rate_ctr_group *ctrg,
+		const struct rate_ctr_desc *desc,
+		int64_t value, int64_t delta);
+	int (*send_item)(struct stats_reporter *srep,
+		const struct stat_item_group *statg,
+		const struct stat_item_desc *desc,
+		int32_t value);
 };
 
 struct stats_config {
diff --git a/src/stats.c b/src/stats.c
index 6189cb38..f4c0b623 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -60,6 +60,14 @@ static struct osmo_timer_list stats_timer;
 
 static int stats_reporter_statsd_open(struct stats_reporter *srep);
 static int stats_reporter_statsd_close(struct stats_reporter *srep);
+static int stats_reporter_statsd_send_counter(struct stats_reporter *srep,
+	const struct rate_ctr_group *ctrg,
+	const struct rate_ctr_desc *desc,
+	int64_t value, int64_t delta);
+static int stats_reporter_statsd_send_item(struct stats_reporter *srep,
+	const struct stat_item_group *statg,
+	const struct stat_item_desc *desc, int value);
+
 static int stats_reporter_send(struct stats_reporter *srep, const char *data,
 	int data_len);
 static int stats_reporter_send_buffer(struct stats_reporter *srep);
@@ -68,20 +76,20 @@ static int update_srep_config(struct stats_reporter *srep)
 {
 	int rc = 0;
 
-	if (srep->type != STATS_REPORTER_STATSD) {
-		srep->enabled = 0;
-		return -ENOTSUP;
-	}
-
 	if (srep->running) {
-		rc = stats_reporter_statsd_close(srep);
+		if (srep->close)
+			rc = srep->close(srep);
 		srep->running = 0;
 	}
 
 	if (!srep->enabled)
 		return rc;
 
-	rc = stats_reporter_statsd_open(srep);
+	if (srep->open)
+		rc = srep->open(srep);
+	else
+		rc = 0;
+
 	if (rc < 0)
 		srep->enabled = 0;
 	else
@@ -310,6 +318,11 @@ struct stats_reporter *stats_reporter_create_statsd(const char *name)
 
 	srep->have_net_config = 1;
 
+	srep->open = stats_reporter_statsd_open;
+	srep->close = stats_reporter_statsd_close;
+	srep->send_counter = stats_reporter_statsd_send_counter;
+	srep->send_item = stats_reporter_statsd_send_item;
+
 	return srep;
 }
 
@@ -461,16 +474,10 @@ static int stats_reporter_send_counter(struct stats_reporter *srep,
 	const struct rate_ctr_desc *desc,
 	int64_t value, int64_t delta)
 {
-	int rc;
-
-	switch (srep->type) {
-	case STATS_REPORTER_STATSD:
-		rc = stats_reporter_statsd_send_counter(srep, ctrg, desc,
-			value, delta);
-		break;
-	}
+	if (!srep->send_counter)
+		return 0;
 
-	return rc;
+	return srep->send_counter(srep, ctrg, desc, value, delta);
 }
 
 static int rate_ctr_handler(
@@ -511,16 +518,10 @@ static int stats_reporter_send_item(struct stats_reporter *srep,
 	const struct stat_item_desc *desc,
 	int32_t value)
 {
-	int rc;
-
-	switch (srep->type) {
-	case STATS_REPORTER_STATSD:
-		rc = stats_reporter_statsd_send_item(srep, statg, desc,
-			value);
-		break;
-	}
+	if (!srep->send_item)
+		return 0;
 
-	return rc;
+	return srep->send_item(srep, statg, desc, value);
 }
 
 static int stat_item_handler(