json-util: Add JSON_BUILD_TRISTATE() and friends

src/libsystemd/sd-json/json-util.h

@@ -142,6 +142,7 @@ enum {
         _JSON_BUILD_STRING_UNDERSCORIFY,
         _JSON_BUILD_DUAL_TIMESTAMP,
         _JSON_BUILD_RATELIMIT,
+        _JSON_BUILD_TRISTATE,
 
         _JSON_BUILD_PAIR_INTEGER_NON_ZERO,
         _JSON_BUILD_PAIR_INTEGER_NON_NEGATIVE,
@@ -164,6 +165,7 @@ enum {
         _JSON_BUILD_PAIR_BASE32HEX_NON_EMPTY,
         _JSON_BUILD_PAIR_HEX_NON_EMPTY,
         _JSON_BUILD_PAIR_OCTESCAPE_NON_EMPTY,
+        _JSON_BUILD_PAIR_TRISTATE_NON_NULL,
 
         _SD_JSON_BUILD_REALLYMAX,
 };
@@ -182,6 +184,7 @@ enum {
 #define JSON_BUILD_STRING_UNDERSCORIFY(s) _JSON_BUILD_STRING_UNDERSCORIFY, (const char *) { s }
 #define JSON_BUILD_DUAL_TIMESTAMP(t) _JSON_BUILD_DUAL_TIMESTAMP, (dual_timestamp*) { t }
 #define JSON_BUILD_RATELIMIT(rl) _JSON_BUILD_RATELIMIT, (const RateLimit*) { rl }
+#define JSON_BUILD_TRISTATE(i) _JSON_BUILD_TRISTATE, (int) { i }
 
 #define JSON_BUILD_PAIR_INTEGER_NON_ZERO(name, i) _JSON_BUILD_PAIR_INTEGER_NON_ZERO, (const char*) { name }, (int64_t) { i }
 #define JSON_BUILD_PAIR_INTEGER_NON_NEGATIVE(name, i) _JSON_BUILD_PAIR_INTEGER_NON_NEGATIVE, (const char*) { name }, (int64_t) { i }
@@ -203,6 +206,7 @@ enum {
 #define JSON_BUILD_PAIR_BASE32HEX_NON_EMPTY(name, v, n) _JSON_BUILD_PAIR_BASE32HEX_NON_EMPTY, (const char*) { name }, (const void*) { v }, (size_t) { n }
 #define JSON_BUILD_PAIR_HEX_NON_EMPTY(name, v, n) _JSON_BUILD_PAIR_HEX_NON_EMPTY, (const char*) { name }, (const void*) { v }, (size_t) { n }
 #define JSON_BUILD_PAIR_OCTESCAPE_NON_EMPTY(name, v, n) _JSON_BUILD_PAIR_HEX_NON_EMPTY, (const char*) { name }, (const void*) { v }, (size_t) { n }
+#define JSON_BUILD_PAIR_TRISTATE_NON_NULL(name, i) _JSON_BUILD_PAIR_TRISTATE_NON_NULL, (const char*) { name }, (int) { i }
 
 #define JSON_BUILD_PAIR_IOVEC_BASE64(name, iov) SD_JSON_BUILD_PAIR(name, JSON_BUILD_IOVEC_BASE64(iov))
 #define JSON_BUILD_PAIR_IOVEC_HEX(name, iov) SD_JSON_BUILD_PAIR(name, JSON_BUILD_IOVEC_HEX(iov))
@@ -215,3 +219,4 @@ enum {
 #define JSON_BUILD_PAIR_STRING_ORDERED_SET(name, s) SD_JSON_BUILD_PAIR(name, JSON_BUILD_STRING_ORDERED_SET(s))
 #define JSON_BUILD_PAIR_DUAL_TIMESTAMP(name, t) SD_JSON_BUILD_PAIR(name, JSON_BUILD_DUAL_TIMESTAMP(t))
 #define JSON_BUILD_PAIR_RATELIMIT(name, rl) SD_JSON_BUILD_PAIR(name, JSON_BUILD_RATELIMIT(rl))
+#define JSON_BUILD_PAIR_TRISTATE(name, i) SD_JSON_BUILD_PAIR(name, JSON_BUILD_TRISTATE(i))

src/libsystemd/sd-json/sd-json.c

@@ -4194,6 +4194,37 @@ _public_ int sd_json_buildv(sd_json_variant **ret, va_list ap) {
                         break;
                 }
 
+                case _JSON_BUILD_TRISTATE: {
+                        int tristate;
+
+                        if (!IN_SET(current->expect, EXPECT_TOPLEVEL, EXPECT_OBJECT_VALUE, EXPECT_ARRAY_ELEMENT)) {
+                                r = -EINVAL;
+                                goto finish;
+                        }
+
+                        tristate = va_arg(ap, int);
+
+                        if (current->n_suppress == 0) {
+                                if (tristate >= 0) {
+                                        r = sd_json_variant_new_boolean(&add, tristate);
+                                        if (r < 0)
+                                                goto finish;
+                                } else
+                                        add = JSON_VARIANT_MAGIC_NULL;
+                        }
+
+                        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 _SD_JSON_BUILD_CALLBACK: {
                         sd_json_build_callback_t cb;
                         void *userdata;
@@ -4805,6 +4836,34 @@ _public_ int sd_json_buildv(sd_json_variant **ret, va_list ap) {
                         current->expect = EXPECT_OBJECT_KEY;
                         break;
                 }
+
+                case _JSON_BUILD_PAIR_TRISTATE_NON_NULL: {
+                        int tristate;
+                        const char *n;
+
+                        if (current->expect != EXPECT_OBJECT_KEY) {
+                                r = -EINVAL;
+                                goto finish;
+                        }
+
+                        n = va_arg(ap, const char*);
+                        tristate = va_arg(ap, int);
+
+                        if (tristate >= 0 && current->n_suppress == 0) {
+                                r = sd_json_variant_new_string(&add, n);
+                                if (r < 0)
+                                        goto finish;
+
+                                r = sd_json_variant_new_boolean(&add_more, tristate);
+                                if (r < 0)
+                                        goto finish;
+                        }
+
+                        n_subtract = 2; /* we generated two item */
+
+                        current->expect = EXPECT_OBJECT_KEY;
+                        break;
+                }
                 }
 
                 /* If variants were generated, add them to our current variant, but only if we are not supposed to suppress additions */