libxl_internal: functions to check default values for builtin types

They will be used in later patch to determine whether we should generate
JSON output for a type. If that type has default value we just skip
generating JSON output.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

tools/libxl/libxl.c

@@ -2860,8 +2860,7 @@ int libxl__device_nic_setdefault(libxl__gc *gc, libxl_device_nic *nic,
         nic->model = strdup("rtl8139");
         if (!nic->model) return ERROR_NOMEM;
     }
-    if (!nic->mac[0] && !nic->mac[1] && !nic->mac[2] &&
-        !nic->mac[3] && !nic->mac[4] && !nic->mac[5]) {
+    if (libxl__mac_is_default(&nic->mac)) {
         const uint8_t *r;
         libxl_uuid uuid;
 

tools/libxl/libxl_cpuid.c

@@ -14,6 +14,11 @@
 
 #include "libxl_internal.h"
 
+int libxl__cpuid_policy_is_empty(libxl_cpuid_policy_list *pl)
+{
+    return !libxl_cpuid_policy_list_length(pl);
+}
+
 void libxl_cpuid_dispose(libxl_cpuid_policy_list *p_cpuid_list)
 {
     int i, j;

tools/libxl/libxl_internal.c

@@ -307,6 +307,12 @@ _hidden int libxl__compare_macs(libxl_mac *a, libxl_mac *b)
     return 0;
 }
 
+_hidden int libxl__mac_is_default(libxl_mac *mac)
+{
+    return (!(*mac)[0] && !(*mac)[1] && !(*mac)[2] &&
+            !(*mac)[3] && !(*mac)[4] && !(*mac)[5]);
+}
+
 _hidden int libxl__init_recursive_mutex(libxl_ctx *ctx, pthread_mutex_t *lock)
 {
     pthread_mutexattr_t attr;

tools/libxl/libxl_internal.h

@@ -1549,6 +1549,8 @@ struct libxl__xen_console_reader {
 _hidden int libxl__parse_mac(const char *s, libxl_mac mac);
 /* compare mac address @a and @b. 0 if the same, -ve if a<b and +ve if a>b */
 _hidden int libxl__compare_macs(libxl_mac *a, libxl_mac *b);
+/* return true if mac address is all zero (the default value) */
+_hidden int libxl__mac_is_default(libxl_mac *mac);
 /* init a recursive mutex */
 _hidden int libxl__init_recursive_mutex(libxl_ctx *ctx, pthread_mutex_t *lock);
 
@@ -3097,6 +3099,10 @@ _hidden int libxl__ms_vm_genid_set(libxl__gc *gc, uint32_t domid,
 #define LIBXL__DEFBOOL_STR_DEFAULT "<default>"
 #define LIBXL__DEFBOOL_STR_FALSE   "False"
 #define LIBXL__DEFBOOL_STR_TRUE    "True"
+static inline int libxl__defbool_is_default(libxl_defbool *db)
+{
+    return !db->val;
+}
 
 /*
  * Inserts "elm_new" into the sorted list "head".
@@ -3193,6 +3199,24 @@ int libxl__random_bytes(libxl__gc *gc, uint8_t *buf, size_t len);
 #define BUILD_BUG_ON(p) ((void)sizeof(char[1 - 2 * !!(p)]))
 #endif
 
+/* This always return false, there's no "default value" for hw cap */
+static inline int libxl__hwcap_is_default(libxl_hwcap *hwcap)
+{
+    return 0;
+}
+
+static inline int libxl__string_list_is_empty(libxl_string_list *psl)
+{
+    return !libxl_string_list_length(psl);
+}
+
+static inline int libxl__key_value_list_is_empty(libxl_key_value_list *pkvl)
+{
+    return !libxl_key_value_list_length(pkvl);
+}
+
+int libxl__cpuid_policy_is_empty(libxl_cpuid_policy_list *pl);
+
 #endif
 
 /*

tools/libxl/libxl_nocpuid.c

@@ -14,6 +14,11 @@
 
 #include "libxl_internal.h"
 
+int libxl__cpuid_policy_is_empty(libxl_cpuid_policy_list *pl)
+{
+    return 1;
+}
+
 void libxl_cpuid_dispose(libxl_cpuid_policy_list *p_cpuid_list)
 {
 }