qapi: Fix c_name() munging

The method c_name() is supposed to do two different actions: munge
'-' into '_', and add a 'q_' prefix to ticklish names.  But it did
these steps out of order, making it possible to submit input that
is not ticklish until after munging, where the output then lacked
the desired prefix.

The failure is exposed easily if you have a compiler that recognizes
C11 keywords, and try to name a member '_Thread-local', as it would
result in trying to compile the declaration 'uint64_t _Thread_local;'
which is not valid.  However, this name violates our conventions
(ultimately, want to enforce that no qapi names start with single
underscore), so the test is slightly weaker by instead testing
'wchar-t'; the declaration 'uint64_t wchar_t;' is valid in C (where
wchar_t is only a typedef) but would fail with a C++ compiler (where
it is a keyword).

Fix things by reversing the order of actions within c_name().

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1447836791-369-18-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

scripts/qapi.py

@@ -1482,10 +1482,11 @@ def c_name(name, protect=True):
                      'not_eq', 'or', 'or_eq', 'xor', 'xor_eq'])
     # namespace pollution:
     polluted_words = set(['unix', 'errno'])
+    name = name.translate(c_name_trans)
     if protect and (name in c89_words | c99_words | c11_words | gcc_words
                     | cpp_words | polluted_words):
         return "q_" + name
-    return name.translate(c_name_trans)
+    return name
 
 eatspace = '\033EATSPACE.'
 pointer_suffix = ' *' + eatspace

tests/qapi-schema/qapi-schema-test.json

@@ -152,12 +152,13 @@
 { 'event': 'EVENT_D',
   'data': { 'a' : 'EventStructOne', 'b' : 'str', '*c': 'str', '*enum3': 'EnumOne' } }
 
-# test that we correctly compile downstream extensions
+# test that we correctly compile downstream extensions, as well as munge
+# ticklish names
 { 'enum': '__org.qemu_x-Enum', 'data': [ '__org.qemu_x-value' ] }
 { 'struct': '__org.qemu_x-Base',
   'data': { '__org.qemu_x-member1': '__org.qemu_x-Enum' } }
 { 'struct': '__org.qemu_x-Struct', 'base': '__org.qemu_x-Base',
-  'data': { '__org.qemu_x-member2': 'str' } }
+  'data': { '__org.qemu_x-member2': 'str', '*wchar-t': 'int' } }
 { 'union': '__org.qemu_x-Union1', 'data': { '__org.qemu_x-branch': 'str' } }
 { 'struct': '__org.qemu_x-Struct2',
   'data': { 'array': ['__org.qemu_x-Union1'] } }

tests/qapi-schema/qapi-schema-test.out

@@ -185,6 +185,7 @@ enum __org.qemu_x-Enum ['__org.qemu_x-value']
 object __org.qemu_x-Struct
     base __org.qemu_x-Base
     member __org.qemu_x-member2: str optional=False
+    member wchar-t: int optional=True
 object __org.qemu_x-Struct2
     member array: __org.qemu_x-Union1List optional=False
 object __org.qemu_x-Union1

tests/test-qmp-commands.c

@@ -65,6 +65,10 @@ __org_qemu_x_Union1 *qmp___org_qemu_x_command(__org_qemu_x_EnumList *a,
     ret->type = ORG_QEMU_X_UNION1_KIND___ORG_QEMU_X_BRANCH;
     ret->u.__org_qemu_x_branch = strdup("blah1");
 
+    /* Also test that 'wchar-t' was munged to 'q_wchar_t' */
+    if (b && b->value && !b->value->has_q_wchar_t) {
+        b->value->q_wchar_t = 1;
+    }
     return ret;
 }