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, 31 insertions, 21 deletions

diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h
index 83ac3ad279..0b5cd4179e 100644
--- a/include/qapi/visitor.h
+++ b/include/qapi/visitor.h
@@ -27,8 +27,8 @@ typedef struct GenericList
     struct GenericList *next;
 } GenericList;
 
-void visit_start_struct(Visitor *v, void **obj, const char *kind,
-                        const char *name, size_t size, Error **errp);
+void visit_start_struct(Visitor *v, const char *name, void **obj,
+                        const char *kind, size_t size, Error **errp);
 void visit_end_struct(Visitor *v, Error **errp);
 void visit_start_implicit_struct(Visitor *v, void **obj, size_t size,
                                  Error **errp);
@@ -43,7 +43,7 @@ void visit_end_list(Visitor *v, Error **errp);
  * corresponding visit_type_*() needs calling; for other visitors,
  * leave *@present unchanged.  Return *@present for convenience.
  */
-bool visit_optional(Visitor *v, bool *present, const char *name);
+bool visit_optional(Visitor *v, const char *name, bool *present);
 
 /**
  * Determine the qtype of the item @name in the current object visit.
@@ -51,24 +51,34 @@ bool visit_optional(Visitor *v, bool *present, const char *name);
  * alternate type; for other visitors, leave *@type unchanged.
  * If @promote_int, treat integers as QTYPE_FLOAT.
  */
-void visit_get_next_type(Visitor *v, QType *type, bool promote_int,
-                         const char *name, Error **errp);
-void visit_type_enum(Visitor *v, int *obj, const char * const strings[],
-                     const char *kind, const char *name, Error **errp);
-void visit_type_int(Visitor *v, int64_t *obj, const char *name, Error **errp);
-void visit_type_uint8(Visitor *v, uint8_t *obj, const char *name, Error **errp);
-void visit_type_uint16(Visitor *v, uint16_t *obj, const char *name, Error **errp);
-void visit_type_uint32(Visitor *v, uint32_t *obj, const char *name, Error **errp);
-void visit_type_uint64(Visitor *v, uint64_t *obj, const char *name, Error **errp);
-void visit_type_int8(Visitor *v, int8_t *obj, const char *name, Error **errp);
-void visit_type_int16(Visitor *v, int16_t *obj, const char *name, Error **errp);
-void visit_type_int32(Visitor *v, int32_t *obj, const char *name, Error **errp);
-void visit_type_int64(Visitor *v, int64_t *obj, const char *name, Error **errp);
-void visit_type_size(Visitor *v, uint64_t *obj, const char *name, Error **errp);
-void visit_type_bool(Visitor *v, bool *obj, const char *name, Error **errp);
-void visit_type_str(Visitor *v, char **obj, const char *name, Error **errp);
-void visit_type_number(Visitor *v, double *obj, const char *name, Error **errp);
-void visit_type_any(Visitor *v, QObject **obj, const char *name, Error **errp);
+void visit_get_next_type(Visitor *v, const char *name, QType *type,
+                         bool promote_int, Error **errp);
+void visit_type_enum(Visitor *v, const char *name, int *obj,
+                     const char *const strings[], const char *kind,
+                     Error **errp);
+void visit_type_int(Visitor *v, const char *name, int64_t *obj, Error **errp);
+void visit_type_uint8(Visitor *v, const char *name, uint8_t *obj,
+                      Error **errp);
+void visit_type_uint16(Visitor *v, const char *name, uint16_t *obj,
+                       Error **errp);
+void visit_type_uint32(Visitor *v, const char *name, uint32_t *obj,
+                       Error **errp);
+void visit_type_uint64(Visitor *v, const char *name, uint64_t *obj,
+                       Error **errp);
+void visit_type_int8(Visitor *v, const char *name, int8_t *obj, Error **errp);
+void visit_type_int16(Visitor *v, const char *name, int16_t *obj,
+                      Error **errp);
+void visit_type_int32(Visitor *v, const char *name, int32_t *obj,
+                      Error **errp);
+void visit_type_int64(Visitor *v, const char *name, int64_t *obj,
+                      Error **errp);
+void visit_type_size(Visitor *v, const char *name, uint64_t *obj,
+                     Error **errp);
+void visit_type_bool(Visitor *v, const char *name, bool *obj, Error **errp);
+void visit_type_str(Visitor *v, const char *name, char **obj, Error **errp);
+void visit_type_number(Visitor *v, const char *name, double *obj,
+                       Error **errp);
+void visit_type_any(Visitor *v, const char *name, QObject **obj, Error **errp);
 bool visit_start_union(Visitor *v, bool data_present, Error **errp);
 
 #endif