qapi: Add alias for ErrorClass

The qapi enum ErrorClass is unusual that it uses 'CamelCase' names,
contrary to our documented convention of preferring 'lower-case'.
However, this enum is entrenched in the API; we cannot change
what strings QMP outputs.  Meanwhile, we want to simplify how
c_enum_const() is used to generate enum constants, by moving away
from the heuristics of camel_to_upper() to a more straightforward
c_name(N).upper() - but doing so will rename all of the ErrorClass
constants and cause churn to all client files, where the new names
are aesthetically less pleasing (ERROR_CLASS_DEVICENOTFOUND looks
like we can't make up our minds on whether to break between words).

So as always in computer science, solve the problem by some more
indirection: rename the qapi type to QapiErrorClass, and add a
new enum ErrorClass in error.h whose members are aliases of the
qapi type, but with the spelling expected elsewhere in the tree.
Then, when c_enum_const() changes the munging, we only have to
adjust the one alias spot.

Suggested by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1447836791-369-26-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/monitor.c b/monitor.c
index 5546f8a..289c118 100644
--- a/monitor.c
+++ b/monitor.c
@@ -403,7 +403,7 @@ static QDict *build_qmp_error_dict(Error *err)
     QObject *obj;
 
     obj = qobject_from_jsonf("{ 'error': { 'class': %s, 'desc': %s } }",
-                             ErrorClass_lookup[error_get_class(err)],
+                             QapiErrorClass_lookup[error_get_class(err)],
                              error_get_pretty(err));
 
     return qobject_to_qdict(obj);