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Re: [Qemu-block] [Qemu-devel] [PATCH 12/18] block-qdict: Clean up qdict_
From: |
Daniel P . Berrangé |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH 12/18] block-qdict: Clean up qdict_crumple() a bit |
Date: |
Thu, 14 Jun 2018 09:46:28 +0100 |
User-agent: |
Mutt/1.9.5 (2018-04-13) |
On Thu, Jun 14, 2018 at 10:40:58AM +0200, Kevin Wolf wrote:
> Am 13.06.2018 um 17:23 hat Markus Armbruster geschrieben:
> > Kevin Wolf <address@hidden> writes:
> >
> > > Am 12.06.2018 um 14:58 hat Markus Armbruster geschrieben:
> > >> When you mix scalar and non-scalar keys, whether you get an "already
> > >> set as scalar" or an "already set as dict" error depends on qdict
> > >> iteration order. Neither message makes much sense. Replace by
> > >> ""Cannot mix scalar and non-scalar keys". This is similar to the
> > >> message we get for mixing list and non-list keys.
> > >>
> > >> I find qdict_crumple()'s first loop hard to understand. Rearrange it
> > >> and add a comment.
> > >>
> > >> Signed-off-by: Markus Armbruster <address@hidden>
> > >
> > > To be honest, I found the old version of the loop more obvious.
> > >
> > >> qobject/block-qdict.c | 42 +++++++++++++++++++++---------------------
> > >> 1 file changed, 21 insertions(+), 21 deletions(-)
> > >>
> > >> diff --git a/qobject/block-qdict.c b/qobject/block-qdict.c
> > >> index a4e1c8d08f..35e9052816 100644
> > >> --- a/qobject/block-qdict.c
> > >> +++ b/qobject/block-qdict.c
> > >> @@ -403,7 +403,7 @@ static int qdict_is_list(QDict *maybe_list, Error
> > >> **errp)
> > >> QObject *qdict_crumple(const QDict *src, Error **errp)
> > >> {
> > >> const QDictEntry *ent;
> > >> - QDict *two_level, *multi_level = NULL;
> > >> + QDict *two_level, *multi_level = NULL, *child_dict;
> > >> QObject *dst = NULL, *child;
> > >> size_t i;
> > >> char *prefix = NULL;
> > >> @@ -422,29 +422,29 @@ QObject *qdict_crumple(const QDict *src, Error
> > >> **errp)
> > >> }
> > >>
> > >> qdict_split_flat_key(ent->key, &prefix, &suffix);
> > >> -
> > >> child = qdict_get(two_level, prefix);
> > >> + child_dict = qobject_to(QDict, child);
> > >> +
> > >> + if (child) {
> > >> + /*
> > >> + * An existing child must be a dict and @ent must be a
> > >> + * dict member (i.e. suffix not null), or else @ent
> > >> + * clashes.
> > >> + */
> > >> + if (!child_dict || !suffix) {
> > >> + error_setg(errp,
> > >> + "Cannot mix scalar and non-scalar keys");
> > >> + goto error;
> > >> + }
> > >> + } else if (suffix) {
> > >> + child_dict = qdict_new();
> > >> + qdict_put(two_level, prefix, child_dict);
> > >> + } else {
> > >> + qdict_put_obj(two_level, prefix, qobject_ref(ent->value));
> > >> + }
> > >
> > > At least, can you please move the else branch to the if below so that
> > > the addition of the new entry is symmetrical for both scalars and dicts?
> > > As the code is, it mixes the conflict check, creation of the child dict
> > > and addition of scalars (but not to the child dict) in a weird way in a
> > > single if block.
> > >
> > > Or maybe organise it like this:
> > >
> > > if (child && !(child_dict && suffix)) {
> > > error
> > > }
> > >
> > > if (suffix) {
> > > if (!child_dict) {
> > > create it
> > > add it to two_level
> > > }
> > > add entry to child_dict
> > > } else {
> > > add entry to two_level
> > > }
> >
> > Fleshing out...
> >
> > if (child && !child_dict) {
> > /*
> > * @prefix already exists and it's a non-dictionary,
> > * i.e. we've seen a scalar with key @prefix. The same
> > * key can't occur twice, therefore suffix must be
> > * non-null.
> > */
> > assert(suffix);
> > /*
> > * @ent has key @address@hidden, but we've already seen
> > * key @prefix: clash.
> > */
> > error_setg(errp, "Cannot mix scalar and non-scalar keys");
> > goto error;
> > }
>
> This catches "foo.bar" after "foo", but not "foo" after "foo.bar".
>
> > if (suffix) {
> > if (!child_dict) {
> > child_dict = qdict_new();
> > qdict_put(two_level, prefix, child_dict);
> > }
> > qdict_put_obj(child_dict, suffix, qobject_ref(ent->value));
> > } else {
> > assert(!child);
>
> So "foo" after "foo.bar" would fail this assertion.
We got coverage of bad inputs in tests/check-qdict.c
If the qdict_crumple_test_bad_inputs doesn't already cover these scenarios
we should extend it to make sure we detect them during testing
Regards,
Daniel
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- [Qemu-block] [PATCH 14/18] check-block-qdict: Rename qdict_flatten()'s variables for clarity, (continued)
- [Qemu-block] [PATCH 14/18] check-block-qdict: Rename qdict_flatten()'s variables for clarity, Markus Armbruster, 2018/06/12
- [Qemu-block] [PATCH 09/18] block: Make remaining uses of qobject input visitor more robust, Markus Armbruster, 2018/06/12
- [Qemu-block] [PATCH 13/18] block-qdict: Simplify qdict_is_list() some, Markus Armbruster, 2018/06/12
- [Qemu-block] [PATCH 15/18] check-block-qdict: Cover flattening of empty lists and dictionaries, Markus Armbruster, 2018/06/12
- [Qemu-block] [PATCH 17/18] rbd: New parameter auth-client-required, Markus Armbruster, 2018/06/12
- [Qemu-block] [PATCH 07/18] block: Clean up a misuse of qobject_to() in .bdrv_co_create_opts(), Markus Armbruster, 2018/06/12
- [Qemu-block] [PATCH 12/18] block-qdict: Clean up qdict_crumple() a bit, Markus Armbruster, 2018/06/12
[Qemu-block] [PATCH 10/18] block-qdict: Simplify qdict_flatten_qdict(), Markus Armbruster, 2018/06/12
[Qemu-block] [PATCH 03/18] block: Add block-specific QDict header, Markus Armbruster, 2018/06/12
[Qemu-block] [PATCH 18/18] rbd: New parameter key-secret, Markus Armbruster, 2018/06/12