[libvirt] [PATCH 3/4] util: Add 'label' field to VIR_ENUM_IMPL

[Cole Robinson]

This allows us to raise error messages from virEnum*String functions.

FromString failure will report this error for value 'zzzz'

  invalid argument: Unknown 'domain type' value 'zzzz'

ToString failure will report this error for unknown type=83

  internal error: Unknown 'domain type' internal value '83'

However we disable the error reporting for now. It should only be
enabled when we decide to begin dropping duplicate error reporting.

Note: this patch will be combined with the next patch when pushing

Signed-off-by: Cole Robinson <crobinso at redhat.com>
---
 docs/apibuild.py   | 12 ++++++++++++
 src/util/virenum.c | 22 ++++++++++++++++++----
 src/util/virenum.h | 15 ++++++++++-----
 3 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/docs/apibuild.py b/docs/apibuild.py
index 9e04871220..1450355eeb 100755
--- a/docs/apibuild.py
+++ b/docs/apibuild.py
@@ -1404,6 +1404,18 @@ class CParser:
             self.error("parsing VIR_ENUM_IMPL: expecting ','", token)
         token = self.token()
 
+        # The 'label' field
+        if token[0] != "string":
+            self.error("parsing VIR_ENUM_IMPL: expecting string", token)
+        token = self.token()
+
+        if token[0] != "sep":
+            self.error("parsing VIR_ENUM_IMPL: expecting ','", token)
+
+        if token[1] != ',':
+            self.error("parsing VIR_ENUM_IMPL: expecting ','", token)
+        token = self.token()
+
         # Now the sentinel name
         if token[0] != "name":
             self.error("parsing VIR_ENUM_IMPL: expecting name", token)
diff --git a/src/util/virenum.c b/src/util/virenum.c
index 26093bd795..58968e7357 100644
--- a/src/util/virenum.c
+++ b/src/util/virenum.c
@@ -60,16 +60,23 @@ virTristateSwitchFromBool(bool val)
 int
 virEnumFromString(const char * const *types,
                   unsigned int ntypes,
-                  const char *type)
+                  const char *type,
+                  const char *label ATTRIBUTE_UNUSED)
 {
     size_t i;
     if (!type)
-        return -1;
+        goto error;
 
     for (i = 0; i < ntypes; i++)
         if (STREQ(types[i], type))
             return i;
 
+ error:
+    /* To be enabled at a later date
+     *
+     * virReportError(VIR_ERR_INVALID_ARG,
+     *              _("Unknown '%s' value '%s'"), label, NULLSTR(type));
+     */
     return -1;
 }
 
@@ -77,10 +84,17 @@ virEnumFromString(const char * const *types,
 const char *
 virEnumToString(const char * const *types,
                 unsigned int ntypes,
-                int type)
+                int type,
+                const char *label ATTRIBUTE_UNUSED)
 {
-    if (type < 0 || type >= ntypes)
+    if (type < 0 || type >= ntypes) {
+        /* To be enabled at a later date
+         *
+         * virReportError(VIR_ERR_INTERNAL_ERROR,
+         *                _("Unknown '%s' internal value %d"), label, type);
+         */
         return NULL;
+    }
 
     return types[type];
 }
diff --git a/src/util/virenum.h b/src/util/virenum.h
index 3ae1a70b72..2c68e7f6a0 100644
--- a/src/util/virenum.h
+++ b/src/util/virenum.h
@@ -24,24 +24,29 @@
 int
 virEnumFromString(const char * const *types,
                   unsigned int ntypes,
-                  const char *type);
+                  const char *type,
+                  const char *label);
 
 const char *
 virEnumToString(const char * const *types,
                 unsigned int ntypes,
-                int type);
+                int type,
+                const char *label);
 
-# define VIR_ENUM_IMPL(name, lastVal, ...) \
+# define VIR_ENUM_IMPL(name, label, lastVal, ...) \
+    static const char *name ## TypeLabel = label; \
     static const char *const name ## TypeList[] = { __VA_ARGS__ }; \
     const char *name ## TypeToString(int type) { \
         return virEnumToString(name ## TypeList, \
                                ARRAY_CARDINALITY(name ## TypeList), \
-                               type); \
+                               type, \
+                               name ## TypeLabel); \
     } \
     int name ## TypeFromString(const char *type) { \
         return virEnumFromString(name ## TypeList, \
                                  ARRAY_CARDINALITY(name ## TypeList), \
-                                 type); \
+                                 type, \
+                                 name ## TypeLabel); \
     } \
     verify(ARRAY_CARDINALITY(name ## TypeList) == lastVal)
 
-- 
2.21.0