Commit cdd2b228 authored by Markus Armbruster's avatar Markus Armbruster
Browse files

qapi: Smooth visitor error checking in generated code 



Use visitor functions' return values to check for failure.  Eliminate
error_propagate() that are now unnecessary.  Delete @err that are now
unused.

Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Message-Id: <20200707160613.848843-41-armbru@redhat.com>
parent b11a093c

docs/devel/qapi-code-gen.txt

+23 −37
Original line number Diff line number Diff line
@@ -1420,8 +1420,6 @@ Example: 


    bool visit_type_UserDefOne_members(Visitor *v, UserDefOne *obj, Error **errp)

    {

        Error *err = NULL;



        if (!visit_type_int(v, "integer", &obj->integer, errp)) {

            return false;

        }
@@ -1430,13 +1428,12 @@ Example: 
                return false;

            }

        }

        error_propagate(errp, err);

        return !err;

        return true;

    }



    bool visit_type_UserDefOne(Visitor *v, const char *name, UserDefOne **obj, Error **errp)

    {

        Error *err = NULL;

        bool ok = false;



        if (!visit_start_struct(v, name, (void **)obj, sizeof(UserDefOne), errp)) {

            return false;
@@ -1446,24 +1443,22 @@ Example: 
            assert(visit_is_dealloc(v));

            goto out_obj;

        }

        visit_type_UserDefOne_members(v, *obj, &err);

        if (err) {

        if (!visit_type_UserDefOne_members(v, *obj, errp)) {

            goto out_obj;

        }

        visit_check_struct(v, &err);

        ok = visit_check_struct(v, errp);

    out_obj:

        visit_end_struct(v, (void **)obj);

        if (err && visit_is_input(v)) {

        if (!ok && visit_is_input(v)) {

            qapi_free_UserDefOne(*obj);

            *obj = NULL;

        }

        error_propagate(errp, err);

        return !err;

        return ok;

    }



    bool visit_type_UserDefOneList(Visitor *v, const char *name, UserDefOneList **obj, Error **errp)

    {

        Error *err = NULL;

        bool ok = false;

        UserDefOneList *tail;

        size_t size = sizeof(**obj);
@@ -1473,33 +1468,27 @@ Example: 


        for (tail = *obj; tail;

             tail = (UserDefOneList *)visit_next_list(v, (GenericList *)tail, size)) {

            visit_type_UserDefOne(v, NULL, &tail->value, &err);

            if (err) {

                break;

            if (!visit_type_UserDefOne(v, NULL, &tail->value, errp)) {

                goto out_obj;

            }

        }



        if (!err) {

            visit_check_list(v, &err);

        }

        ok = visit_check_list(v, errp);

    out_obj:

        visit_end_list(v, (void **)obj);

        if (err && visit_is_input(v)) {

        if (!ok && visit_is_input(v)) {

            qapi_free_UserDefOneList(*obj);

            *obj = NULL;

        }

        error_propagate(errp, err);

        return !err;

        return ok;

    }



    bool visit_type_q_obj_my_command_arg_members(Visitor *v, q_obj_my_command_arg *obj, Error **errp)

    {

        Error *err = NULL;



        if (!visit_type_UserDefOneList(v, "arg1", &obj->arg1, errp)) {

            return false;

        }

        error_propagate(errp, err);

        return !err;

        return true;

    }



[Uninteresting stuff omitted...]
@@ -1554,15 +1543,12 @@ Example: 


    static void qmp_marshal_output_UserDefOne(UserDefOne *ret_in, QObject **ret_out, Error **errp)

    {

        Error *err = NULL;

        Visitor *v;



        v = qobject_output_visitor_new(ret_out);

        visit_type_UserDefOne(v, "unused", &ret_in, &err);

        if (!err) {

        if (visit_type_UserDefOne(v, "unused", &ret_in, errp)) {

            visit_complete(v, ret_out);

        }

        error_propagate(errp, err);

        visit_free(v);

        v = qapi_dealloc_visitor_new();

        visit_type_UserDefOne(v, "unused", &ret_in, NULL);
@@ -1572,33 +1558,32 @@ Example: 
    void qmp_marshal_my_command(QDict *args, QObject **ret, Error **errp)

    {

        Error *err = NULL;

        bool ok = false;

        Visitor *v;

        UserDefOne *retval;

        q_obj_my_command_arg arg = {0};



        v = qobject_input_visitor_new(QOBJECT(args));

        visit_start_struct(v, NULL, NULL, 0, &err);

        if (err) {

        if (!visit_start_struct(v, NULL, NULL, 0, errp)) {

            goto out;

        }

        visit_type_q_obj_my_command_arg_members(v, &arg, &err);

        if (!err) {

            visit_check_struct(v, &err);

        if (visit_type_q_obj_my_command_arg_members(v, &arg, errp)) {

            ok = visit_check_struct(v, errp);

        }

        visit_end_struct(v, NULL);

        if (err) {

        if (!ok) {

            goto out;

        }



        retval = qmp_my_command(arg.arg1, &err);

        error_propagate(errp, err);

        if (err) {

            goto out;

        }



        qmp_marshal_output_UserDefOne(retval, ret, &err);

        qmp_marshal_output_UserDefOne(retval, ret, errp);



    out:

        error_propagate(errp, err);

        visit_free(v);

        v = qapi_dealloc_visitor_new();

        visit_start_struct(v, NULL, NULL, 0, NULL);
@@ -1606,6 +1591,7 @@ Example: 
        visit_end_struct(v, NULL);

        visit_free(v);

    }



[Uninteresting stuff omitted...]

    $ cat qapi-generated/example-qapi-init-commands.h

[Uninteresting stuff omitted...]

scripts/qapi/commands.py

+9 −13
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ def gen_call(name, arg_type, boxed, ret_type): 
    ret = mcgen('''



    %(lhs)sqmp_%(c_name)s(%(args)s&err);

    error_propagate(errp, err);

''',

                c_name=c_name(name), args=argstr, lhs=lhs)

    if ret_type:
@@ -55,7 +56,7 @@ def gen_call(name, arg_type, boxed, ret_type): 
        goto out;

    }



    qmp_marshal_output_%(c_name)s(retval, ret, &err);

    qmp_marshal_output_%(c_name)s(retval, ret, errp);

''',

                     c_name=ret_type.c_name())

    return ret
@@ -66,15 +67,12 @@ def gen_marshal_output(ret_type): 


static void qmp_marshal_output_%(c_name)s(%(c_type)s ret_in, QObject **ret_out, Error **errp)

{

    Error *err = NULL;

    Visitor *v;



    v = qobject_output_visitor_new(ret_out);

    visit_type_%(c_name)s(v, "unused", &ret_in, &err);

    if (!err) {

    if (visit_type_%(c_name)s(v, "unused", &ret_in, errp)) {

        visit_complete(v, ret_out);

    }

    error_propagate(errp, err);

    visit_free(v);

    v = qapi_dealloc_visitor_new();

    visit_type_%(c_name)s(v, "unused", &ret_in, NULL);
@@ -104,6 +102,7 @@ def gen_marshal(name, arg_type, boxed, ret_type): 
%(proto)s

{

    Error *err = NULL;

    bool ok = false;

    Visitor *v;

''',

                proto=build_marshal_proto(name))
@@ -123,28 +122,26 @@ def gen_marshal(name, arg_type, boxed, ret_type): 
    ret += mcgen('''



    v = qobject_input_visitor_new(QOBJECT(args));

    visit_start_struct(v, NULL, NULL, 0, &err);

    if (err) {

    if (!visit_start_struct(v, NULL, NULL, 0, errp)) {

        goto out;

    }

''')



    if have_args:

        ret += mcgen('''

    visit_type_%(c_arg_type)s_members(v, &arg, &err);

    if (!err) {

        visit_check_struct(v, &err);

    if (visit_type_%(c_arg_type)s_members(v, &arg, errp)) {

        ok = visit_check_struct(v, errp);

    }

''',

                     c_arg_type=arg_type.c_name())

    else:

        ret += mcgen('''

    visit_check_struct(v, &err);

    ok = visit_check_struct(v, errp);

''')



    ret += mcgen('''

    visit_end_struct(v, NULL);

    if (err) {

    if (!ok) {

        goto out;

    }

''')
@@ -154,7 +151,6 @@ def gen_marshal(name, arg_type, boxed, ret_type): 
    ret += mcgen('''



out:

    error_propagate(errp, err);

    visit_free(v);

''')

scripts/qapi/visit.py

+23 −34
Original line number Diff line number Diff line
@@ -41,8 +41,6 @@ def gen_visit_object_members(name, base, members, variants): 


bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)

{

    Error *err = NULL;



''',

                c_name=c_name(name))
@@ -97,8 +95,7 @@ bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp) 
            else:

                ret += mcgen('''

    case %(case)s:

        visit_type_%(c_type)s_members(v, &obj->u.%(c_name)s, &err);

        break;

        return visit_type_%(c_type)s_members(v, &obj->u.%(c_name)s, errp);

''',

                             case=case_str,

                             c_type=var.type.c_name(), c_name=c_name(var.name))
@@ -111,8 +108,7 @@ bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp) 
''')



    ret += mcgen('''

    error_propagate(errp, err);

    return !err;

    return true;

}

''')

    return ret
@@ -123,7 +119,7 @@ def gen_visit_list(name, element_type): 


bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)

{

    Error *err = NULL;

    bool ok = false;

    %(c_name)s *tail;

    size_t size = sizeof(**obj);
@@ -133,22 +129,19 @@ bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error 


    for (tail = *obj; tail;

         tail = (%(c_name)s *)visit_next_list(v, (GenericList *)tail, size)) {

        visit_type_%(c_elt_type)s(v, NULL, &tail->value, &err);

        if (err) {

            break;

        if (!visit_type_%(c_elt_type)s(v, NULL, &tail->value, errp)) {

            goto out_obj;

        }

    }



    if (!err) {

        visit_check_list(v, &err);

    }

    ok = visit_check_list(v, errp);

out_obj:

    visit_end_list(v, (void **)obj);

    if (err && visit_is_input(v)) {

    if (!ok && visit_is_input(v)) {

        qapi_free_%(c_name)s(*obj);

        *obj = NULL;

    }

    error_propagate(errp, err);

    return !err;

    return ok;

}

''',

                 c_name=c_name(name), c_elt_type=element_type.c_name())
@@ -173,7 +166,7 @@ def gen_visit_alternate(name, variants): 


bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)

{

    Error *err = NULL;

    bool ok = false;



    if (!visit_start_alternate(v, name, (GenericAlternate **)obj,

                               sizeof(**obj), errp)) {
@@ -182,6 +175,7 @@ bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error 
    if (!*obj) {

        /* incomplete */

        assert(visit_is_dealloc(v));

        ok = true;

        goto out_obj;

    }

    switch ((*obj)->type) {
@@ -196,13 +190,11 @@ bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error 
                     case=var.type.alternate_qtype())

        if isinstance(var.type, QAPISchemaObjectType):

            ret += mcgen('''

        visit_start_struct(v, name, NULL, 0, &err);

        if (err) {

        if (!visit_start_struct(v, name, NULL, 0, errp)) {

            break;

        }

        visit_type_%(c_type)s_members(v, &(*obj)->u.%(c_name)s, &err);

        if (!err) {

            visit_check_struct(v, &err);

        if (visit_type_%(c_type)s_members(v, &(*obj)->u.%(c_name)s, errp)) {

            ok = visit_check_struct(v, errp);

        }

        visit_end_struct(v, NULL);

''',
@@ -210,7 +202,7 @@ bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error 
                         c_name=c_name(var.name))

        else:

            ret += mcgen('''

        visit_type_%(c_type)s(v, name, &(*obj)->u.%(c_name)s, &err);

        ok = visit_type_%(c_type)s(v, name, &(*obj)->u.%(c_name)s, errp);

''',

                         c_type=var.type.c_name(),

                         c_name=c_name(var.name))
@@ -224,7 +216,7 @@ bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error 
        abort();

    default:

        assert(visit_is_input(v));

        error_setg(&err, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",

        error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",

                   "%(name)s");

        /* Avoid passing invalid *obj to qapi_free_%(c_name)s() */

        g_free(*obj);
@@ -232,12 +224,11 @@ bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error 
    }

out_obj:

    visit_end_alternate(v, (void **)obj);

    if (err && visit_is_input(v)) {

    if (!ok && visit_is_input(v)) {

        qapi_free_%(c_name)s(*obj);

        *obj = NULL;

    }

    error_propagate(errp, err);

    return !err;

    return ok;

}

''',

                 name=name, c_name=c_name(name))
@@ -250,7 +241,7 @@ def gen_visit_object(name, base, members, variants): 


bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)

{

    Error *err = NULL;

    bool ok = false;



    if (!visit_start_struct(v, name, (void **)obj, sizeof(%(c_name)s), errp)) {

        return false;
@@ -260,19 +251,17 @@ bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error 
        assert(visit_is_dealloc(v));

        goto out_obj;

    }

    visit_type_%(c_name)s_members(v, *obj, &err);

    if (err) {

    if (!visit_type_%(c_name)s_members(v, *obj, errp)) {

        goto out_obj;

    }

    visit_check_struct(v, &err);

    ok = visit_check_struct(v, errp);

out_obj:

    visit_end_struct(v, (void **)obj);

    if (err && visit_is_input(v)) {

    if (!ok && visit_is_input(v)) {

        qapi_free_%(c_name)s(*obj);

        *obj = NULL;

    }

    error_propagate(errp, err);

    return !err;

    return ok;

}

''',

                 c_name=c_name(name))