From c89a9af036a9063903537404d615bed04a700e5b Mon Sep 17 00:00:00 2001
From: Bruce Richardson <[email protected]>
Date: Fri, 21 Oct 2022 15:37:04 +0800
Subject: [PATCH 188/189] telemetry: eliminate duplicate code for json output
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When preparing the json response to a telemetry socket query, the code
for prefixing the command name, and appending the file "}" on the end of
the response was duplicated for multiple reply types. Taking this code
out of the switch statement reduces the duplication and makes the code
more maintainable.

For completeness of testing, add in a test case to validate the "null"
response type - the only leg of the switch statement not already covered
by an existing test case in the telemetry_data tests.

Signed-off-by: Bruce Richardson <[email protected]>
Acked-by: Ciara Power <[email protected]>
Acked-by: Morten Brørup <[email protected]>
Acked-by: Chengwen Feng <[email protected]>
---
 lib/telemetry/telemetry.c | 35 ++++++++++++-----------------------
 1 file changed, 12 insertions(+), 23 deletions(-)

diff --git a/lib/telemetry/telemetry.c b/lib/telemetry/telemetry.c
index f0be50b2bf..25ab6ed877 100644
--- a/lib/telemetry/telemetry.c
+++ b/lib/telemetry/telemetry.c
@@ -235,27 +235,22 @@ output_json(const char *cmd, const struct rte_tel_data *d, int s)
 
 	RTE_BUILD_BUG_ON(sizeof(out_buf) < MAX_CMD_LEN +
 			RTE_TEL_MAX_SINGLE_STRING_LEN + 10);
+
+	prefix_used = snprintf(out_buf, sizeof(out_buf), "{\"%.*s\":",
+			MAX_CMD_LEN, cmd);
+	cb_data_buf = &out_buf[prefix_used];
+	buf_len = sizeof(out_buf) - prefix_used - 1; /* space for '}' */
+
 	switch (d->type) {
 	case RTE_TEL_NULL:
-		used = snprintf(out_buf, sizeof(out_buf), "{\"%.*s\":null}",
-				MAX_CMD_LEN, cmd ? cmd : "none");
+		used = strlcpy(cb_data_buf, "null", buf_len);
 		break;
-	case RTE_TEL_STRING:
-		prefix_used = snprintf(out_buf, sizeof(out_buf), "{\"%.*s\":",
-				MAX_CMD_LEN, cmd);
-		cb_data_buf = &out_buf[prefix_used];
-		buf_len = sizeof(out_buf) - prefix_used - 1; /* space for '}' */
 
+	case RTE_TEL_STRING:
 		used = rte_tel_json_str(cb_data_buf, buf_len, 0, d->data.str);
-		used += prefix_used;
-		used += strlcat(out_buf + used, "}", sizeof(out_buf) - used);
 		break;
-	case RTE_TEL_DICT:
-		prefix_used = snprintf(out_buf, sizeof(out_buf), "{\"%.*s\":",
-				MAX_CMD_LEN, cmd);
-		cb_data_buf = &out_buf[prefix_used];
-		buf_len = sizeof(out_buf) - prefix_used - 1; /* space for '}' */
 
+	case RTE_TEL_DICT:
 		used = rte_tel_json_empty_obj(cb_data_buf, buf_len, 0);
 		for (i = 0; i < d->data_len; i++) {
 			const struct tel_dict_entry *v = &d->data.dict[i];
@@ -291,18 +286,12 @@ output_json(const char *cmd, const struct rte_tel_data *d, int s)
 			}
 			}
 		}
-		used += prefix_used;
-		used += strlcat(out_buf + used, "}", sizeof(out_buf) - used);
 		break;
+
 	case RTE_TEL_ARRAY_STRING:
 	case RTE_TEL_ARRAY_INT:
 	case RTE_TEL_ARRAY_U64:
 	case RTE_TEL_ARRAY_CONTAINER:
-		prefix_used = snprintf(out_buf, sizeof(out_buf), "{\"%.*s\":",
-				MAX_CMD_LEN, cmd);
-		cb_data_buf = &out_buf[prefix_used];
-		buf_len = sizeof(out_buf) - prefix_used - 1; /* space for '}' */
-
 		used = rte_tel_json_empty_array(cb_data_buf, buf_len, 0);
 		for (i = 0; i < d->data_len; i++)
 			if (d->type == RTE_TEL_ARRAY_STRING)
@@ -330,10 +319,10 @@ output_json(const char *cmd, const struct rte_tel_data *d, int s)
 				if (!rec_data->keep)
 					rte_tel_data_free(rec_data->data);
 			}
-		used += prefix_used;
-		used += strlcat(out_buf + used, "}", sizeof(out_buf) - used);
 		break;
 	}
+	used += prefix_used;
+	used += strlcat(out_buf + used, "}", sizeof(out_buf) - used);
 	if (write(s, out_buf, used) < 0)
 		perror("Error writing to socket");
 }
-- 
2.23.0