Patchwork [17/18] Implement qdict_flatten()

login
register
mail settings
Submitter Kevin Wolf
Date July 23, 2013, 1:03 p.m.
Message ID <1374584606-5615-18-git-send-email-kwolf@redhat.com>
Download mbox | patch
Permalink /patch/261078/
State New
Headers show

Comments

Kevin Wolf - July 23, 2013, 1:03 p.m.
qdict_flatten(): For each nested QDict with key x, all fields with key y
are moved to this QDict and their key is renamed to "x.y". This operation
is applied recursively for nested QDicts.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 include/qapi/qmp/qdict.h |  1 +
 qobject/qdict.c          | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)
Eric Blake - July 26, 2013, 4:40 p.m.
On 07/23/2013 07:03 AM, Kevin Wolf wrote:
> qdict_flatten(): For each nested QDict with key x, all fields with key y
> are moved to this QDict and their key is renamed to "x.y". This operation
> is applied recursively for nested QDicts.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  include/qapi/qmp/qdict.h |  1 +
>  qobject/qdict.c          | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 51 insertions(+)


> +    while (entry != NULL) {
> +
> +        next = qdict_next(qdict, entry);

next points to a position in the unmodified qdict...

> +        value = qdict_entry_value(entry);
> +        new_key = NULL;
> +        delete = false;
> +
> +        if (prefix) {
> +            qobject_incref(value);
> +            new_key = g_strdup_printf("%s.%s", prefix, entry->key);
> +            qdict_put_obj(target, new_key, value);
> +            delete = true;
> +        }
> +
> +        if (qobject_type(value) == QTYPE_QDICT) {
> +            qdict_do_flatten(qobject_to_qdict(value), target,
> +                             new_key ? new_key : entry->key);
> +            delete = true;
> +        }
> +
> +        if (delete) {
> +            qdict_del(qdict, entry->key);
> +
> +            /* Restart loop after modifying the iterated QDict */
> +            entry = qdict_first(qdict);

...now entry points to the head of the modified qdict, since the
modification may have re-arranged where we would iterate next...

> +        }
> +
> +        entry = next;

...oops, we just undid that, and pointed it back to the old qdict
iteration location.  I think you're missing a continue statement inside
'if (delete)'.

If you agree with my analysis and incorporate my suggested fix, then I'm
okay if you add:

Reviewed-by: Eric Blake <eblake@redhat.com>
Kevin Wolf - July 26, 2013, 5:03 p.m.
Am 26.07.2013 um 18:40 hat Eric Blake geschrieben:
> On 07/23/2013 07:03 AM, Kevin Wolf wrote:
> > qdict_flatten(): For each nested QDict with key x, all fields with key y
> > are moved to this QDict and their key is renamed to "x.y". This operation
> > is applied recursively for nested QDicts.
> > 
> > Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> > ---
> >  include/qapi/qmp/qdict.h |  1 +
> >  qobject/qdict.c          | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 51 insertions(+)
> 
> 
> > +    while (entry != NULL) {
> > +
> > +        next = qdict_next(qdict, entry);
> 
> next points to a position in the unmodified qdict...
> 
> > +        value = qdict_entry_value(entry);
> > +        new_key = NULL;
> > +        delete = false;
> > +
> > +        if (prefix) {
> > +            qobject_incref(value);
> > +            new_key = g_strdup_printf("%s.%s", prefix, entry->key);
> > +            qdict_put_obj(target, new_key, value);
> > +            delete = true;
> > +        }
> > +
> > +        if (qobject_type(value) == QTYPE_QDICT) {
> > +            qdict_do_flatten(qobject_to_qdict(value), target,
> > +                             new_key ? new_key : entry->key);
> > +            delete = true;
> > +        }
> > +
> > +        if (delete) {
> > +            qdict_del(qdict, entry->key);
> > +
> > +            /* Restart loop after modifying the iterated QDict */
> > +            entry = qdict_first(qdict);
> 
> ...now entry points to the head of the modified qdict, since the
> modification may have re-arranged where we would iterate next...
> 
> > +        }
> > +
> > +        entry = next;
> 
> ...oops, we just undid that, and pointed it back to the old qdict
> iteration location.  I think you're missing a continue statement inside
> 'if (delete)'.

Gah, this is getting embarrassing. Who stole my continue? :-)

You're right of course, thanks for catching that. I'll fix it.

Kevin

Patch

diff --git a/include/qapi/qmp/qdict.h b/include/qapi/qmp/qdict.h
index 685b2e3..d6855d1 100644
--- a/include/qapi/qmp/qdict.h
+++ b/include/qapi/qmp/qdict.h
@@ -65,5 +65,6 @@  int qdict_get_try_bool(const QDict *qdict, const char *key, int def_value);
 const char *qdict_get_try_str(const QDict *qdict, const char *key);
 
 QDict *qdict_clone_shallow(const QDict *src);
+void qdict_flatten(QDict *qdict);
 
 #endif /* QDICT_H */
diff --git a/qobject/qdict.c b/qobject/qdict.c
index ed381f9..108db47 100644
--- a/qobject/qdict.c
+++ b/qobject/qdict.c
@@ -476,3 +476,53 @@  static void qdict_destroy_obj(QObject *obj)
 
     g_free(qdict);
 }
+
+static void qdict_do_flatten(QDict *qdict, QDict *target, const char *prefix)
+{
+    QObject *value;
+    const QDictEntry *entry, *next;
+    const char *new_key;
+    bool delete;
+
+    entry = qdict_first(qdict);
+
+    while (entry != NULL) {
+
+        next = qdict_next(qdict, entry);
+        value = qdict_entry_value(entry);
+        new_key = NULL;
+        delete = false;
+
+        if (prefix) {
+            qobject_incref(value);
+            new_key = g_strdup_printf("%s.%s", prefix, entry->key);
+            qdict_put_obj(target, new_key, value);
+            delete = true;
+        }
+
+        if (qobject_type(value) == QTYPE_QDICT) {
+            qdict_do_flatten(qobject_to_qdict(value), target,
+                             new_key ? new_key : entry->key);
+            delete = true;
+        }
+
+        if (delete) {
+            qdict_del(qdict, entry->key);
+
+            /* Restart loop after modifying the iterated QDict */
+            entry = qdict_first(qdict);
+        }
+
+        entry = next;
+    }
+}
+
+/**
+ * qdict_flatten(): For each nested QDict with key x, all fields with key y
+ * are moved to this QDict and their key is renamed to "x.y". This operation
+ * is applied recursively for nested QDicts.
+ */
+void qdict_flatten(QDict *qdict)
+{
+    qdict_do_flatten(qdict, qdict, NULL);
+}