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qdict: Make qdict_flatten() shallow-clone-friendly

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In its current form, qdict_flatten() removes all entries from nested
QDicts that are moved to the root QDict.  It is completely sufficient to
remove all old entries from the root QDict, however.  If the nested
dicts have a refcount of 1, this will automatically delete them, too.
And if they have a greater refcount, we probably do not want to modify
them in the first place.

The latter observation means that it was currently (in general)
impossible to qdict_flatten() a shallowly cloned dict because that would
empty nested QDicts in the original dict as well.  This patch changes
this, so you can now use qdict_flatten(qdict_shallow_clone(dict)) to get
a flattened copy without disturbing the original.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20180611205203.2624-7-mreitz@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This commit is contained in:
Max Reitz 2018-06-11 22:51:59 +02:00 committed by Markus Armbruster
parent f030ffd39d
commit bf6e6a37ee
1 changed files with 15 additions and 4 deletions
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19
qobject/block-qdict.c
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@ -114,19 +114,30 @@ static void qdict_flatten_qdict(QDict *qdict, QDict *target, const char *prefix)
/*
* Flatten non-empty QDict and QList recursively into @target,
* copy other objects to @target
* copy other objects to @target.
* On the root level (if @qdict == @target), remove flattened
* nested QDicts and QLists from @qdict.
*
* (Note that we do not need to remove entries from nested
* dicts or lists. Their reference count is decremented on
* the root level, so there are no leaks. In fact, if they
* have a reference count greater than one, we are probably
* well advised not to modify them altogether.)
*/
if (dict_val && qdict_size(dict_val)) {
qdict_flatten_qdict(dict_val, target,
new_key ? new_key : entry->key);
qdict_del(qdict, entry->key);
if (target == qdict) {
qdict_del(qdict, entry->key);
}
} else if (list_val && !qlist_empty(list_val)) {
qdict_flatten_qlist(list_val, target,
new_key ? new_key : entry->key);
qdict_del(qdict, entry->key);
if (target == qdict) {
qdict_del(qdict, entry->key);
}
} else if (target != qdict) {
qdict_put_obj(target, new_key, qobject_ref(value));
qdict_del(qdict, entry->key);
}
g_free(new_key);