[Qemu-devel] [PATCH V5 03/10] qapi script: check correctness of discriminator values in union

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

It will check whether the values specified are written correctly,
and whether all enum values are covered, when discriminator is a
pre-defined enum type

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 scripts/qapi-visit.py |   17 +++++++++++++++++
 scripts/qapi.py       |   31 +++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 0 deletions(-)

diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 65f1a54..c0efb5f 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -255,6 +255,23 @@ def generate_visit_union(expr):
         assert not base
         return generate_visit_anon_union(name, members)
 
+    # If discriminator is specified and it is a pre-defined enum in schema,
+    # check its correctness
+    enum_define = discriminator_find_enum_define(expr)
+    if enum_define:
+        for key in members:
+            if not key in enum_define["enum_values"]:
+                sys.stderr.write("Discriminator value '%s' is not found in "
+                                 "enum '%s'\n" %
+                                 (key, enum_define["enum_name"]))
+                sys.exit(1)
+        for key in enum_define["enum_values"]:
+            if not key in members:
+                sys.stderr.write("Enum value '%s' is not covered by a branch "
+                                 "of union '%s'\n" %
+                                 (key, name))
+                sys.exit(1)
+
     ret = generate_visit_enum('%sKind' % name, members.keys())
 
     if base:
diff --git a/scripts/qapi.py b/scripts/qapi.py
index aa91edc..3f50d52 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -385,3 +385,34 @@ def guardend(name):
 
 ''',
                  name=guardname(name))
+
+# This function can be used to check whether "base" is valid
+def find_base_fields(base):
+    base_struct_define = find_struct(base)
+    if not base_struct_define:
+        return None
+    return base_struct_define.get('data')
+
+# Return the discriminator enum define, if discriminator is specified in
+# @expr and it is a pre-defined enum type
+def discriminator_find_enum_define(expr):
+    discriminator = expr.get('discriminator')
+    base = expr.get('base')
+
+    # Only support discriminator when base present
+    if not (discriminator and base):
+        return None
+
+    base_fields = find_base_fields(base)
+
+    if not base_fields:
+        raise StandardError("Base '%s' is not a valid type\n"
+                            % base)
+
+    discriminator_type = base_fields.get(discriminator)
+
+    if not discriminator_type:
+        raise StandardError("Discriminator '%s' not found in schema\n"
+                            % discriminator)
+
+    return find_enum(discriminator_type)
-- 
1.7.1