qapi-visit: Add visitor.type classification

We have three classes of QAPI visitors: input, output, and dealloc.
Currently, all implementations of these visitors have one thing in
common based on their visitor type: the implementation used for the
visit_type_enum() callback.  But since we plan to add more such
common behavior, in relation to documenting and further refining
the semantics, it makes more sense to have the visitor
implementations advertise which class they belong to, so the common
qapi-visit-core code can use that information in multiple places.

A later patch will better document the types of visitors directly
in visitor.h.

For this patch, knowing the class of a visitor implementation lets
us make input_type_enum() and output_type_enum() become static
functions, by replacing the callback function Visitor.type_enum()
with the simpler enum member Visitor.type.  Share a common
assertion in qapi-visit-core as part of the refactoring.

Move comments in opts-visitor.c to match the refactored layout.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1461879932-9020-2-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

1 files changed, 15 insertions, 13 deletions

diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index fa680c9..3cd7edc 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -72,12 +72,6 @@ bool visit_optional(Visitor *v, const char *name, bool *present)
     return *present;
 }
 
-void visit_type_enum(Visitor *v, const char *name, int *obj,
-                     const char *const strings[], Error **errp)
-{
-    v->type_enum(v, name, obj, strings, errp);
-}
-
 void visit_type_int(Visitor *v, const char *name, int64_t *obj, Error **errp)
 {
     v->type_int64(v, name, obj, errp);
@@ -208,14 +202,13 @@ void visit_type_any(Visitor *v, const char *name, QObject **obj, Error **errp)
     v->type_any(v, name, obj, errp);
 }
 
-void output_type_enum(Visitor *v, const char *name, int *obj,
-                      const char *const strings[], Error **errp)
+static void output_type_enum(Visitor *v, const char *name, int *obj,
+                             const char *const strings[], Error **errp)
 {
     int i = 0;
     int value = *obj;
     char *enum_str;
 
-    assert(strings);
     while (strings[i++] != NULL);
     if (value < 0 || value >= i - 1) {
         error_setg(errp, QERR_INVALID_PARAMETER, name ? name : "null");
@@ -226,15 +219,13 @@ void output_type_enum(Visitor *v, const char *name, int *obj,
     visit_type_str(v, name, &enum_str, errp);
 }
 
-void input_type_enum(Visitor *v, const char *name, int *obj,
-                     const char *const strings[], Error **errp)
+static void input_type_enum(Visitor *v, const char *name, int *obj,
+                            const char *const strings[], Error **errp)
 {
     Error *local_err = NULL;
     int64_t value = 0;
     char *enum_str;
 
-    assert(strings);
-
     visit_type_str(v, name, &enum_str, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
@@ -257,3 +248,14 @@ void input_type_enum(Visitor *v, const char *name, int *obj,
     g_free(enum_str);
     *obj = value;
 }
+
+void visit_type_enum(Visitor *v, const char *name, int *obj,
+                     const char *const strings[], Error **errp)
+{
+    assert(strings);
+    if (v->type == VISITOR_INPUT) {
+        input_type_enum(v, name, obj, strings, errp);
+    } else if (v->type == VISITOR_OUTPUT) {
+        output_type_enum(v, name, obj, strings, errp);
+    }
+}