qapi: De-duplicate enum code generation

Duplicated in commit 21cd70d.  Yes, we can't import qapi-types, but
that's no excuse.  Move the helpers from qapi-types.py to qapi.py, and
replace the duplicates in qapi-event.py.

The generated event enumeration type's lookup table becomes
const-correct (see commit 2e4450f), and uses explicit indexes instead
of relying on order (see commit 912ae9c).

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1442401589-24189-10-git-send-email-armbru@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

docs/qapi-code-gen.txt

@@ -829,9 +829,9 @@ Example:
         QDECREF(qmp);
     }
 
-    const char *example_QAPIEvent_lookup[] = {
+    const char *const example_QAPIEvent_lookup[] = {
-        "MY_EVENT",
+        [EXAMPLE_QAPI_EVENT_MY_EVENT] = "MY_EVENT",
-        NULL,
+        [EXAMPLE_QAPI_EVENT_MAX] = NULL,
     };
     $ cat qapi-generated/example-qapi-event.h
 [Uninteresting stuff omitted...]
@@ -846,10 +846,11 @@ Example:
 
     void qapi_event_send_my_event(Error **errp);
 
-    extern const char *example_QAPIEvent_lookup[];
     typedef enum example_QAPIEvent {
         EXAMPLE_QAPI_EVENT_MY_EVENT = 0,
         EXAMPLE_QAPI_EVENT_MAX = 1,
     } example_QAPIEvent;
 
+    extern const char *const example_QAPIEvent_lookup[];
+
     #endif

scripts/qapi-event.py

@@ -153,63 +153,6 @@ def generate_event_implement(api_name, event_name, params):
 
     return ret
 
-
-# Following are the functions that generate an enum type for all defined
-# events, similar to qapi-types.py. Here we already have enum name and
-# values which were generated before and recorded in event_enum_*. It also
-# works around the issue that "import qapi-types" can't work.
-
-def generate_event_enum_decl(event_enum_name, event_enum_values):
-    lookup_decl = mcgen('''
-
-extern const char *%(event_enum_name)s_lookup[];
-''',
-                        event_enum_name = event_enum_name)
-
-    enum_decl = mcgen('''
-typedef enum %(event_enum_name)s {
-''',
-                      event_enum_name = event_enum_name)
-
-    # append automatically generated _MAX value
-    enum_max_value = c_enum_const(event_enum_name, "MAX")
-    enum_values = event_enum_values + [ enum_max_value ]
-
-    i = 0
-    for value in enum_values:
-        enum_decl += mcgen('''
-    %(value)s = %(i)d,
-''',
-                     value = value,
-                     i = i)
-        i += 1
-
-    enum_decl += mcgen('''
-} %(event_enum_name)s;
-''',
-                       event_enum_name = event_enum_name)
-
-    return lookup_decl + enum_decl
-
-def generate_event_enum_lookup(event_enum_name, event_enum_strings):
-    ret = mcgen('''
-
-const char *%(event_enum_name)s_lookup[] = {
-''',
-                event_enum_name = event_enum_name)
-
-    for string in event_enum_strings:
-        ret += mcgen('''
-    "%(string)s",
-''',
-                     string = string)
-
-    ret += mcgen('''
-    NULL,
-};
-''')
-    return ret
-
 (input_file, output_dir, do_c, do_h, prefix, dummy) = parse_command_line()
 
 c_comment = '''
@@ -266,8 +209,7 @@ fdecl.write(mcgen('''
 exprs = QAPISchema(input_file).get_exprs()
 
 event_enum_name = c_name(prefix + "QAPIEvent", protect=False)
-event_enum_values = []
+event_names = []
-event_enum_strings = []
 
 for expr in exprs:
     if expr.has_key('event'):
@@ -286,12 +228,11 @@ for expr in exprs:
         fdef.write(ret)
 
         # Record it, and generate enum later
-        event_enum_values.append(event_enum_value)
+        event_names.append(event_name)
-        event_enum_strings.append(event_name)
 
-ret = generate_event_enum_decl(event_enum_name, event_enum_values)
+ret = generate_enum(event_enum_name, event_names)
 fdecl.write(ret)
-ret = generate_event_enum_lookup(event_enum_name, event_enum_strings)
+ret = generate_enum_lookup(event_enum_name, event_names)
 fdef.write(ret)
 
 close_output(fdef, fdecl)

scripts/qapi-types.py

@@ -80,61 +80,6 @@ struct %(name)s {
 
     return ret
 
-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, prefix)
-        ret += mcgen('''
-    [%(index)s] = "%(value)s",
-''',
-                     index = index, value = value)
-
-    max_index = c_enum_const(name, 'MAX', prefix)
-    ret += mcgen('''
-    [%(max_index)s] = NULL,
-};
-''',
-        max_index=max_index)
-    return ret
-
-def generate_enum(name, values, prefix=None):
-    name = c_name(name)
-    lookup_decl = mcgen('''
-
-extern const char *const %(name)s_lookup[];
-''',
-                name=name)
-
-    enum_decl = mcgen('''
-
-typedef enum %(name)s {
-''',
-                name=name)
-
-    # append automatically generated _MAX value
-    enum_values = values + [ 'MAX' ]
-
-    i = 0
-    for value in enum_values:
-        enum_full_value = c_enum_const(name, value, prefix)
-        enum_decl += mcgen('''
-    %(enum_full_value)s = %(i)d,
-''',
-                     enum_full_value = enum_full_value,
-                     i=i)
-        i += 1
-
-    enum_decl += mcgen('''
-} %(name)s;
-''',
-                 name=name)
-
-    return enum_decl + lookup_decl
-
 def gen_alternate_qtypes_decl(name):
     return mcgen('''
 

scripts/qapi.py

@@ -1498,6 +1498,61 @@ def guardend(name):
 ''',
                  name=guardname(name))
 
+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, prefix)
+        ret += mcgen('''
+    [%(index)s] = "%(value)s",
+''',
+                     index = index, value = value)
+
+    max_index = c_enum_const(name, 'MAX', prefix)
+    ret += mcgen('''
+    [%(max_index)s] = NULL,
+};
+''',
+        max_index=max_index)
+    return ret
+
+def generate_enum(name, values, prefix=None):
+    name = c_name(name)
+    lookup_decl = mcgen('''
+
+extern const char *const %(name)s_lookup[];
+''',
+                name=name)
+
+    enum_decl = mcgen('''
+
+typedef enum %(name)s {
+''',
+                name=name)
+
+    # append automatically generated _MAX value
+    enum_values = values + [ 'MAX' ]
+
+    i = 0
+    for value in enum_values:
+        enum_full_value = c_enum_const(name, value, prefix)
+        enum_decl += mcgen('''
+    %(enum_full_value)s = %(i)d,
+''',
+                     enum_full_value = enum_full_value,
+                     i=i)
+        i += 1
+
+    enum_decl += mcgen('''
+} %(name)s;
+''',
+                 name=name)
+
+    return enum_decl + lookup_decl
+
 #
 # Common command line parsing
 #