qapi: Swap visit_* arguments for consistent 'name' placement

JSON uses "name":value, but many of our visitor interfaces were
called with visit_type_FOO(v, &value, name, errp).  This can be
a bit confusing to have to mentally swap the parameter order to
match JSON order.  It's particularly bad for visit_start_struct(),
where the 'name' parameter is smack in the middle of the
otherwise-related group of 'obj, kind, size' parameters! It's
time to do a global swap of the parameter ordering, so that the
'name' parameter is always immediately after the Visitor argument.

Additional reason in favor of the swap: the existing include/qjson.h
prefers listing 'name' first in json_prop_*(), and I have plans to
unify that file with the qapi visitors; listing 'name' first in
qapi will minimize churn to the (admittedly few) qjson.h clients.

Later patches will then fix docs, object.h, visitor-impl.h, and
those clients to match.

Done by first patching scripts/qapi*.py by hand to make generated
files do what I want, then by running the following Coccinelle
script to affect the rest of the code base:
 $ spatch --sp-file script `git grep -l '\bvisit_' -- '**/*.[ch]'`
I then had to apply some touchups (Coccinelle insisted on TAB
indentation in visitor.h, and botched the signature of
visit_type_enum() by rewriting 'const char *const strings[]' to
the syntactically invalid 'const char*const[] strings').  The
movement of parameters is sufficient to provoke compiler errors
if any callers were missed.

    // Part 1: Swap declaration order
    @@
    type TV, TErr, TObj, T1, T2;
    identifier OBJ, ARG1, ARG2;
    @@
     void visit_start_struct
    -(TV v, TObj OBJ, T1 ARG1, const char *name, T2 ARG2, TErr errp)
    +(TV v, const char *name, TObj OBJ, T1 ARG1, T2 ARG2, TErr errp)
     { ... }

    @@
    type bool, TV, T1;
    identifier ARG1;
    @@
     bool visit_optional
    -(TV v, T1 ARG1, const char *name)
    +(TV v, const char *name, T1 ARG1)
     { ... }

    @@
    type TV, TErr, TObj, T1;
    identifier OBJ, ARG1;
    @@
     void visit_get_next_type
    -(TV v, TObj OBJ, T1 ARG1, const char *name, TErr errp)
    +(TV v, const char *name, TObj OBJ, T1 ARG1, TErr errp)
     { ... }

    @@
    type TV, TErr, TObj, T1, T2;
    identifier OBJ, ARG1, ARG2;
    @@
     void visit_type_enum
    -(TV v, TObj OBJ, T1 ARG1, T2 ARG2, const char *name, TErr errp)
    +(TV v, const char *name, TObj OBJ, T1 ARG1, T2 ARG2, TErr errp)
     { ... }

    @@
    type TV, TErr, TObj;
    identifier OBJ;
    identifier VISIT_TYPE =~ "^visit_type_";
    @@
     void VISIT_TYPE
    -(TV v, TObj OBJ, const char *name, TErr errp)
    +(TV v, const char *name, TObj OBJ, TErr errp)
     { ... }

    // Part 2: swap caller order
    @@
    expression V, NAME, OBJ, ARG1, ARG2, ERR;
    identifier VISIT_TYPE =~ "^visit_type_";
    @@
    (
    -visit_start_struct(V, OBJ, ARG1, NAME, ARG2, ERR)
    +visit_start_struct(V, NAME, OBJ, ARG1, ARG2, ERR)
    |
    -visit_optional(V, ARG1, NAME)
    +visit_optional(V, NAME, ARG1)
    |
    -visit_get_next_type(V, OBJ, ARG1, NAME, ERR)
    +visit_get_next_type(V, NAME, OBJ, ARG1, ERR)
    |
    -visit_type_enum(V, OBJ, ARG1, ARG2, NAME, ERR)
    +visit_type_enum(V, NAME, OBJ, ARG1, ARG2, ERR)
    |
    -VISIT_TYPE(V, OBJ, NAME, ERR)
    +VISIT_TYPE(V, NAME, OBJ, ERR)
    )

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1454075341-13658-19-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 7d05d3fc96..b46cb580a0 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -120,21 +120,21 @@ static void balloon_stats_get_all(Object *obj, Visitor *v,
     VirtIOBalloon *s = opaque;
     int i;
 
-    visit_start_struct(v, NULL, "guest-stats", name, 0, &err);
+    visit_start_struct(v, name, NULL, "guest-stats", 0, &err);
     if (err) {
         goto out;
     }
-    visit_type_int(v, &s->stats_last_update, "last-update", &err);
+    visit_type_int(v, "last-update", &s->stats_last_update, &err);
     if (err) {
         goto out_end;
     }
 
-    visit_start_struct(v, NULL, NULL, "stats", 0, &err);
+    visit_start_struct(v, "stats", NULL, NULL, 0, &err);
     if (err) {
         goto out_end;
     }
     for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
-        visit_type_uint64(v, &s->stats[i], balloon_stat_names[i], &err);
+        visit_type_uint64(v, balloon_stat_names[i], &s->stats[i], &err);
         if (err) {
             break;
         }
@@ -156,7 +156,7 @@ static void balloon_stats_get_poll_interval(Object *obj, Visitor *v,
                                             Error **errp)
 {
     VirtIOBalloon *s = opaque;
-    visit_type_int(v, &s->stats_poll_interval, name, errp);
+    visit_type_int(v, name, &s->stats_poll_interval, errp);
 }
 
 static void balloon_stats_set_poll_interval(Object *obj, Visitor *v,
@@ -167,7 +167,7 @@ static void balloon_stats_set_poll_interval(Object *obj, Visitor *v,
     Error *local_err = NULL;
     int64_t value;
 
-    visit_type_int(v, &value, name, &local_err);
+    visit_type_int(v, name, &value, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         return;