qapi: allow override of default enum prefix naming

The camel_to_upper() method applies some heuristics to turn
a mixed case type name into an all-uppercase name. This is
used for example, to generate enum constant name prefixes.

The heuristics don't also generate a satisfactory name
though. eg

  { 'enum': 'QCryptoTLSCredsEndpoint',
    'data': ['client', 'server']}

Results in Q_CRYPTOTLS_CREDS_ENDPOINT_CLIENT. This has
an undesirable _ after the initial Q and is missing an
_ between the CRYPTO & TLS strings.

Rather than try to add more and more heuristics to try
to cope with this, simply allow the QAPI schema to
specify the desired enum constant prefix explicitly.

eg

  { 'enum': 'QCryptoTLSCredsEndpoint',
    'prefix': 'QCRYPTO_TLS_CREDS_ENDPOINT',
    'data': ['client', 'server']}

Now gives the QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT name.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

2 files changed, 17 insertions, 9 deletions

diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
index f2428f3..a8453d1 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi-types.py
@@ -101,20 +101,20 @@ struct %(name)s {
 
     return ret
 
-def generate_enum_lookup(name, values):
+def generate_enum_lookup(name, values, prefix=None):
     ret = mcgen('''
 
 const char *const %(name)s_lookup[] = {
 ''',
                 name=c_name(name))
     for value in values:
-        index = c_enum_const(name, value)
+        index = c_enum_const(name, value, prefix)
         ret += mcgen('''
     [%(index)s] = "%(value)s",
 ''',
                      index = index, value = value)
 
-    max_index = c_enum_const(name, 'MAX')
+    max_index = c_enum_const(name, 'MAX', prefix)
     ret += mcgen('''
     [%(max_index)s] = NULL,
 };
@@ -122,7 +122,7 @@ const char *const %(name)s_lookup[] = {
         max_index=max_index)
     return ret
 
-def generate_enum(name, values):
+def generate_enum(name, values, prefix=None):
     name = c_name(name)
     lookup_decl = mcgen('''
 
@@ -141,7 +141,7 @@ typedef enum %(name)s {
 
     i = 0
     for value in enum_values:
-        enum_full_value = c_enum_const(name, value)
+        enum_full_value = c_enum_const(name, value, prefix)
         enum_decl += mcgen('''
     %(enum_full_value)s = %(i)d,
 ''',
@@ -348,9 +348,11 @@ for expr in exprs:
     if expr.has_key('struct'):
         ret += generate_fwd_struct(expr['struct'])
     elif expr.has_key('enum'):
-        ret += generate_enum(expr['enum'], expr['data'])
+        ret += generate_enum(expr['enum'], expr['data'],
+                             expr.get('prefix'))
         ret += generate_fwd_enum_struct(expr['enum'])
-        fdef.write(generate_enum_lookup(expr['enum'], expr['data']))
+        fdef.write(generate_enum_lookup(expr['enum'], expr['data'],
+                                        expr.get('prefix')))
     elif expr.has_key('union'):
         ret += generate_fwd_struct(expr['union'])
         enum_define = discriminator_find_enum_define(expr)
diff --git a/scripts/qapi.py b/scripts/qapi.py
index 88fa073..c4423b7 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -634,11 +634,15 @@ def check_alternate(expr, expr_info):
 def check_enum(expr, expr_info):
     name = expr['enum']
     members = expr.get('data')
+    prefix = expr.get('prefix')
     values = { 'MAX': '(automatic)' }
 
     if not isinstance(members, list):
         raise QAPIExprError(expr_info,
                             "Enum '%s' requires an array for 'data'" % name)
+    if prefix is not None and not isinstance(prefix, str):
+        raise QAPIExprError(expr_info,
+                            "Enum '%s' requires a string for 'prefix'" % name)
     for member in members:
         check_name(expr_info, "Member of enum '%s'" %name, member,
                    enum_member=True)
@@ -693,7 +697,7 @@ def check_exprs(exprs):
         expr = expr_elem['expr']
         info = expr_elem['info']
         if expr.has_key('enum'):
-            check_keys(expr_elem, 'enum', ['data'])
+            check_keys(expr_elem, 'enum', ['data'], ['prefix'])
             add_enum(expr['enum'], info, expr['data'])
         elif expr.has_key('union'):
             check_keys(expr_elem, 'union', ['data'],
@@ -813,7 +817,9 @@ def camel_to_upper(value):
         new_name += c
     return new_name.lstrip('_').upper()
 
-def c_enum_const(type_name, const_name):
+def c_enum_const(type_name, const_name, prefix=None):
+    if prefix is not None:
+        type_name = prefix
     return camel_to_upper(type_name + '_' + const_name)
 
 c_name_trans = string.maketrans('.-', '__')