json: Introduce JSON_BUILD_STRING_SET

src/shared/json.c

@@ -21,6 +21,7 @@
 #include "math-util.h"
 #include "memory-util.h"
 #include "memstream-util.h"
+#include "set.h"
 #include "string-table.h"
 #include "string-util.h"
 #include "strv.h"
@@ -3877,6 +3878,40 @@ int json_buildv(JsonVariant **ret, va_list ap) {
                         break;
                 }
 
+                case _JSON_BUILD_STRING_SET: {
+                        Set *set;
+
+                        if (!IN_SET(current->expect, EXPECT_TOPLEVEL, EXPECT_OBJECT_VALUE, EXPECT_ARRAY_ELEMENT)) {
+                                r = -EINVAL;
+                                goto finish;
+                        }
+
+                        set = va_arg(ap, Set*);
+
+                        if (current->n_suppress == 0) {
+                                _cleanup_free_ char **sorted = NULL;
+
+                                r = set_dump_sorted(set, (void ***) &sorted, NULL);
+                                if (r < 0)
+                                        goto finish;
+
+                                r = json_variant_new_array_strv(&add, sorted);
+                                if (r < 0)
+                                        goto finish;
+                        }
+
+                        n_subtract = 1;
+
+                        if (current->expect == EXPECT_TOPLEVEL)
+                                current->expect = EXPECT_END;
+                        else if (current->expect == EXPECT_OBJECT_VALUE)
+                                current->expect = EXPECT_OBJECT_KEY;
+                        else
+                                assert(current->expect == EXPECT_ARRAY_ELEMENT);
+
+                        break;
+                }
+
                 case _JSON_BUILD_OBJECT_BEGIN:
 
                         if (!IN_SET(current->expect, EXPECT_TOPLEVEL, EXPECT_OBJECT_VALUE, EXPECT_ARRAY_ELEMENT)) {

src/shared/json.h

@@ -275,6 +275,7 @@ enum {
         _JSON_BUILD_UUID,
         _JSON_BUILD_BYTE_ARRAY,
         _JSON_BUILD_HW_ADDR,
+        _JSON_BUILD_STRING_SET,
         _JSON_BUILD_PAIR_UNSIGNED_NON_ZERO,
         _JSON_BUILD_PAIR_FINITE_USEC,
         _JSON_BUILD_PAIR_STRING_NON_EMPTY,
@@ -319,6 +320,7 @@ enum {
 #define JSON_BUILD_IN_ADDR(v, f) JSON_BUILD_BYTE_ARRAY(((const union in_addr_union*) { v })->bytes, FAMILY_ADDRESS_SIZE_SAFE(f))
 #define JSON_BUILD_ETHER_ADDR(v) JSON_BUILD_BYTE_ARRAY(((const struct ether_addr*) { v })->ether_addr_octet, sizeof(struct ether_addr))
 #define JSON_BUILD_HW_ADDR(v) _JSON_BUILD_HW_ADDR, (const struct hw_addr_data*) { v }
+#define JSON_BUILD_STRING_SET(s) _JSON_BUILD_STRING_SET, (Set *) { s }
 
 #define JSON_BUILD_PAIR_STRING(name, s) JSON_BUILD_PAIR(name, JSON_BUILD_STRING(s))
 #define JSON_BUILD_PAIR_INTEGER(name, i) JSON_BUILD_PAIR(name, JSON_BUILD_INTEGER(i))
@@ -344,6 +346,7 @@ enum {
 #define JSON_BUILD_PAIR_IN_ADDR(name, v, f) JSON_BUILD_PAIR(name, JSON_BUILD_IN_ADDR(v, f))
 #define JSON_BUILD_PAIR_ETHER_ADDR(name, v) JSON_BUILD_PAIR(name, JSON_BUILD_ETHER_ADDR(v))
 #define JSON_BUILD_PAIR_HW_ADDR(name, v) JSON_BUILD_PAIR(name, JSON_BUILD_HW_ADDR(v))
+#define JSON_BUILD_PAIR_STRING_SET(name, s) JSON_BUILD_PAIR(name, JSON_BUILD_STRING_SET(s))
 
 #define JSON_BUILD_PAIR_UNSIGNED_NON_ZERO(name, u) _JSON_BUILD_PAIR_UNSIGNED_NON_ZERO, (const char*) { name }, (uint64_t) { u }
 #define JSON_BUILD_PAIR_FINITE_USEC(name, u) _JSON_BUILD_PAIR_FINITE_USEC, (const char*) { name }, (usec_t) { u }