| Message ID | 20180611205203.2624-7-mreitz@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | block: Try to create well typed json:{} filenames | expand |
Max Reitz <mreitz@redhat.com> writes: > 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> > --- > qobject/block-qdict.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/qobject/block-qdict.c b/qobject/block-qdict.c > index 0b2ae02627..7e0deb74c5 100644 > --- a/qobject/block-qdict.c > +++ b/qobject/block-qdict.c > @@ -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); This simply makes sense, even without the later patch(es) that rely on it. Reviewed-by: Markus Armbruster <armbru@redhat.com>
diff --git a/qobject/block-qdict.c b/qobject/block-qdict.c index 0b2ae02627..7e0deb74c5 100644 --- a/qobject/block-qdict.c +++ b/qobject/block-qdict.c @@ -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);
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> --- qobject/block-qdict.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-)