qapi: New parse_qapi_name()

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1488317230-26248-19-git-send-email-armbru@redhat.com>

include/qapi/util.h

@@ -14,4 +14,6 @@
 int qapi_enum_parse(const char * const lookup[], const char *buf,
                     int max, int def, Error **errp);
 
+int parse_qapi_name(const char *name, bool complete);
+
 #endif

qapi/qapi-util.c

@@ -33,3 +33,50 @@ int qapi_enum_parse(const char * const lookup[], const char *buf,
     error_setg(errp, "invalid parameter value: %s", buf);
     return def;
 }
+
+/*
+ * Parse a valid QAPI name from @str.
+ * A valid name consists of letters, digits, hyphen and underscore.
+ * It may be prefixed by __RFQDN_ (downstream extension), where RFQDN
+ * may contain only letters, digits, hyphen and period.
+ * The special exception for enumeration names is not implemented.
+ * See docs/qapi-code-gen.txt for more on QAPI naming rules.
+ * Keep this consistent with scripts/qapi.py!
+ * If @complete, the parse fails unless it consumes @str completely.
+ * Return its length on success, -1 on failure.
+ */
+int parse_qapi_name(const char *str, bool complete)
+{
+    const char *p = str;
+
+    if (*p == '_') {            /* Downstream __RFQDN_ */
+        p++;
+        if (*p != '_') {
+            return -1;
+        }
+        while (*++p) {
+            if (!qemu_isalnum(*p) && *p != '-' && *p != '.') {
+                break;
+            }
+        }
+
+        if (*p != '_') {
+            return -1;
+        }
+        p++;
+    }
+
+    if (!qemu_isalpha(*p)) {
+        return -1;
+    }
+    while (*++p) {
+        if (!qemu_isalnum(*p) && *p != '-' && *p != '_') {
+            break;
+        }
+    }
+
+    if (complete && *p) {
+        return -1;
+    }
+    return p - str;
+}

tests/test-qapi-util.c

@@ -42,10 +42,44 @@ static void test_qapi_enum_parse(void)
     g_assert_cmpint(ret, ==, QTYPE__MAX - 1);
 }
 
+static void test_parse_qapi_name(void)
+{
+    int ret;
+
+    /* Must start with a letter */
+    ret = parse_qapi_name("a", true);
+    g_assert(ret == 1);
+    ret = parse_qapi_name("a$", false);
+    g_assert(ret == 1);
+    ret = parse_qapi_name("", false);
+    g_assert(ret == -1);
+    ret = parse_qapi_name("1", false);
+    g_assert(ret == -1);
+
+    /* Only letters, digits, hyphen, underscore */
+    ret = parse_qapi_name("A-Za-z0-9_", true);
+    g_assert(ret == 10);
+    ret = parse_qapi_name("A-Za-z0-9_$", false);
+    g_assert(ret == 10);
+    ret = parse_qapi_name("A-Za-z0-9_$", true);
+    g_assert(ret == -1);
+
+    /* __RFQDN_ */
+    ret = parse_qapi_name("__com.redhat_supports", true);
+    g_assert(ret == 21);
+    ret = parse_qapi_name("_com.example_", false);
+    g_assert(ret == -1);
+    ret = parse_qapi_name("__com.example", false);
+    g_assert(ret == -1);
+    ret = parse_qapi_name("__com.example_", false);
+    g_assert(ret == -1);
+}
+
 int main(int argc, char *argv[])
 {
     g_test_init(&argc, &argv, NULL);
     g_test_add_func("/qapi/util/qapi_enum_parse", test_qapi_enum_parse);
+    g_test_add_func("/qapi/util/parse_qapi_name", test_parse_qapi_name);
     g_test_run();
     return 0;
 }