From: Phil Sutter <phil@nwl.cc>
Date: Fri, 27 Sep 2024 22:55:34 +0000 (+0200)
Subject: json: Support typeof in set and map types
X-Git-Url: http://git.ipfire.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=5ba01aecc101d55bbe1e93b3d29614fb84052f54;p=thirdparty%2Fnftables.git

json: Support typeof in set and map types

commit bb6312484af93a83a9ec8716f3887a43566a775a upstream.

Implement this as a special "type" property value which is an object
with sole property "typeof". The latter's value is the JSON
representation of the expression in set->key, so for concatenated
typeofs it is a concat expression.

All this is a bit clumsy right now but it works and it should be
possible to tear it down a bit for more user-friendliness in a
compatible way by either replacing the concat expression by the array it
contains or even the whole "typeof" object - the parser would just
assume any object (or objects in an array) in the "type" property value
are expressions to extract a type from.

Signed-off-by: Phil Sutter <phil@nwl.cc>
---

diff --git a/doc/libnftables-json.adoc b/doc/libnftables-json.adoc
index 1cce0e69..10c17fa1 100644
--- a/doc/libnftables-json.adoc
+++ b/doc/libnftables-json.adoc
@@ -332,7 +332,7 @@ ____
 	"auto-merge":* 'BOOLEAN'
 *}}*
 
-'SET_TYPE' := 'STRING' | *[* 'SET_TYPE_LIST' *]*
+'SET_TYPE' := 'STRING' | *[* 'SET_TYPE_LIST' *]* | *{ "typeof":* 'EXPRESSION' *}*
 'SET_TYPE_LIST' := 'STRING' [*,* 'SET_TYPE_LIST' ]
 'SET_POLICY' := *"performance"* | *"memory"*
 'SET_FLAG_LIST' := 'SET_FLAG' [*,* 'SET_FLAG_LIST' ]
@@ -372,8 +372,9 @@ that they translate a unique key to a value.
 	Automatic merging of adjacent/overlapping set elements in interval sets.
 
 ==== TYPE
-The set type might be a string, such as *"ipv4_addr"* or an array
-consisting of strings (for concatenated types).
+The set type might be a string, such as *"ipv4_addr"*, an array
+consisting of strings (for concatenated types) or a *typeof* object containing
+an expression to extract the type from.
 
 ==== ELEM
 A single set element might be given as string, integer or boolean value for
diff --git a/src/json.c b/src/json.c
index e950157f..9e4e1c1f 100644
--- a/src/json.c
+++ b/src/json.c
@@ -86,6 +86,17 @@ static json_t *set_dtype_json(const struct expr *key)
 	return root;
 }
 
+static json_t *set_key_dtype_json(const struct set *set,
+				  struct output_ctx *octx)
+{
+	bool use_typeof = set->key_typeof_valid;
+
+	if (!use_typeof)
+		return set_dtype_json(set->key);
+
+	return json_pack("{s:o}", "typeof", expr_print_json(set->key, octx));
+}
+
 static json_t *stmt_print_json(const struct stmt *stmt, struct output_ctx *octx)
 {
 	char buf[1024];
@@ -148,7 +159,7 @@ static json_t *set_print_json(struct output_ctx *octx, const struct set *set)
 			"family", family2str(set->handle.family),
 			"name", set->handle.set.name,
 			"table", set->handle.table.name,
-			"type", set_dtype_json(set->key),
+			"type", set_key_dtype_json(set, octx),
 			"handle", set->handle.handle.id);
 
 	if (set->comment)
diff --git a/src/parser_json.c b/src/parser_json.c
index 5f66a38b..f37304ad 100644
--- a/src/parser_json.c
+++ b/src/parser_json.c
@@ -1657,7 +1657,16 @@ static struct expr *json_parse_dtype_expr(struct json_ctx *ctx, json_t *root)
 			compound_expr_add(expr, i);
 		}
 		return expr;
+	} else if (json_is_object(root)) {
+		const char *key;
+		json_t *val;
+
+		if (!json_unpack_stmt(ctx, root, &key, &val) &&
+		    !strcmp(key, "typeof")) {
+			return json_parse_expr(ctx, val);
+		}
 	}
+
 	json_error(ctx, "Invalid set datatype.");
 	return NULL;
 }