[PATCH v3 1/5] kvargs: add one new process API

[Chengwen Feng]

The rte_kvargs_process() was used to parse key-value (e.g. socket_id=0),
it also supports to parse only-key (e.g. socket_id). But many drivers's
callback can only handle key-value, it will segment fault if handles
only-key. so the patchset [1] was introduced.

Because the patchset [1] modified too much drivers, therefore:
1) A new API rte_kvargs_process_opt() was introduced, it inherits the
function of rte_kvargs_process() which could parse both key-value and
only-key.
2) Constraint the rte_kvargs_process() can only parse key-value.

[1] https://patches.dpdk.org/project/dpdk/patch/20230320092110.37295-1-fengchengwen@huawei.com/

Signed-off-by: Chengwen Feng <fengchengwen at huawei.com>
---
 lib/kvargs/rte_kvargs.c | 29 ++++++++++++++++++++++++++++-
 lib/kvargs/rte_kvargs.h | 28 ++++++++++++++++++++++++++++
 lib/kvargs/version.map  |  3 +++
 3 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/lib/kvargs/rte_kvargs.c b/lib/kvargs/rte_kvargs.c
index c77bb82feb..5ce8664238 100644
--- a/lib/kvargs/rte_kvargs.c
+++ b/lib/kvargs/rte_kvargs.c
@@ -168,7 +168,7 @@ rte_kvargs_count(const struct rte_kvargs *kvlist, const char *key_match)
 }
 
 /*
- * For each matching key, call the given handler function.
+ * For each matching key in key/value, call the given handler function.
  */
 int
 rte_kvargs_process(const struct rte_kvargs *kvlist,
@@ -179,6 +179,33 @@ rte_kvargs_process(const struct rte_kvargs *kvlist,
 	const struct rte_kvargs_pair *pair;
 	unsigned i;
 
+	if (kvlist == NULL)
+		return 0;
+
+	for (i = 0; i < kvlist->count; i++) {
+		pair = &kvlist->pairs[i];
+		if (pair->value == NULL)
+			continue;
+		if (key_match == NULL || strcmp(pair->key, key_match) == 0) {
+			if ((*handler)(pair->key, pair->value, opaque_arg) < 0)
+				return -1;
+		}
+	}
+	return 0;
+}
+
+/*
+ * For each matching key in key/value or only-key, call the given handler function.
+ */
+int
+rte_kvargs_process_opt(const struct rte_kvargs *kvlist,
+		       const char *key_match,
+		       arg_handler_t handler,
+		       void *opaque_arg)
+{
+	const struct rte_kvargs_pair *pair;
+	unsigned int i;
+
 	if (kvlist == NULL)
 		return 0;
 
diff --git a/lib/kvargs/rte_kvargs.h b/lib/kvargs/rte_kvargs.h
index 4900b750bc..522e83f757 100644
--- a/lib/kvargs/rte_kvargs.h
+++ b/lib/kvargs/rte_kvargs.h
@@ -195,6 +195,34 @@ const char *rte_kvargs_get_with_value(const struct rte_kvargs *kvlist,
 int rte_kvargs_process(const struct rte_kvargs *kvlist,
 	const char *key_match, arg_handler_t handler, void *opaque_arg);
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Call a handler function for each key/value or only-key matching the key
+ *
+ * For each key/value or only-key association that matches the given key, calls
+ * the handler function with the for a given arg_name passing the value on the
+ * dictionary for that key and a given extra argument.
+ *
+ * @param kvlist
+ *   The rte_kvargs structure. No error if NULL.
+ * @param key_match
+ *   The key on which the handler should be called, or NULL to process handler
+ *   on all associations
+ * @param handler
+ *   The function to call for each matching key
+ * @param opaque_arg
+ *   A pointer passed unchanged to the handler
+ *
+ * @return
+ *   - 0 on success
+ *   - Negative on error
+ */
+__rte_experimental
+int rte_kvargs_process_opt(const struct rte_kvargs *kvlist,
+	const char *key_match, arg_handler_t handler, void *opaque_arg);
+
 /**
  * Count the number of associations matching the given key
  *
diff --git a/lib/kvargs/version.map b/lib/kvargs/version.map
index 387a94e725..15d482e9b3 100644
--- a/lib/kvargs/version.map
+++ b/lib/kvargs/version.map
@@ -16,4 +16,7 @@ EXPERIMENTAL {
 
 	# added in 21.11
 	rte_kvargs_get_with_value;
+
+	# added in 23.11
+	rte_kvargs_process_opt;
 };
-- 
2.17.1