qapi: Move gen_enum(), gen_enum_lookup() back to qapi/types.py

The next commit will split up qapi/common.py.  gen_enum() needs
QAPISchemaEnumMember, and that's in the way.  Move it to qapi/types.py
along with its buddy gen_enum_lookup().

Permit me a short a digression on history: how did gen_enum() end up
in qapi/common.py?  Commit 21cd70dfc1 "qapi script: add event support"
duplicated qapi-types.py's gen_enum() and gen_enum_lookup() in
qapi-event.py.  Simply importing them would have been cleaner, but
wasn't possible as qapi-types.py was a program, not a module.  Commit
efd2eaa6c2 "qapi: De-duplicate enum code generation" de-duplicated by
moving them to qapi.py, which was a module.

Since then, program qapi-types.py has morphed into module types.py.
It's where gen_enum() and gen_enum_lookup() started, and where they
belong.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20191018074345.24034-6-armbru@redhat.com>

1 files changed, 59 insertions, 0 deletions

diff --git a/scripts/qapi/types.py b/scripts/qapi/types.py
index 3edd9374aa..711543147d 100644
--- a/scripts/qapi/types.py
+++ b/scripts/qapi/types.py
@@ -21,6 +21,65 @@ from qapi.common import *
 objects_seen = set()
 
 
+def gen_enum_lookup(name, members, prefix=None):
+    ret = mcgen('''
+
+const QEnumLookup %(c_name)s_lookup = {
+    .array = (const char *const[]) {
+''',
+                c_name=c_name(name))
+    for m in members:
+        ret += gen_if(m.ifcond)
+        index = c_enum_const(name, m.name, prefix)
+        ret += mcgen('''
+        [%(index)s] = "%(name)s",
+''',
+                     index=index, name=m.name)
+        ret += gen_endif(m.ifcond)
+
+    ret += mcgen('''
+    },
+    .size = %(max_index)s
+};
+''',
+                 max_index=c_enum_const(name, '_MAX', prefix))
+    return ret
+
+
+def gen_enum(name, members, prefix=None):
+    # append automatically generated _MAX value
+    enum_members = members + [QAPISchemaEnumMember('_MAX', None)]
+
+    ret = mcgen('''
+
+typedef enum %(c_name)s {
+''',
+                c_name=c_name(name))
+
+    for m in enum_members:
+        ret += gen_if(m.ifcond)
+        ret += mcgen('''
+    %(c_enum)s,
+''',
+                     c_enum=c_enum_const(name, m.name, prefix))
+        ret += gen_endif(m.ifcond)
+
+    ret += mcgen('''
+} %(c_name)s;
+''',
+                 c_name=c_name(name))
+
+    ret += mcgen('''
+
+#define %(c_name)s_str(val) \\
+    qapi_enum_lookup(&%(c_name)s_lookup, (val))
+
+extern const QEnumLookup %(c_name)s_lookup;
+''',
+                 c_name=c_name(name))
+    return ret
+
+
 def gen_fwd_object_or_array(name):
     return mcgen('''