[Qemu-devel] [RFC v6 02/27] qobject: introduce qstring_get_try_str()

[Peter Xu <peterx@redhat.com>]

The only difference from qstring_get_str() is that it allows the qstring
to be NULL.  If so, NULL is returned.

CC: Eric Blake <eblake@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/qapi/qmp/qstring.h |  1 +
 qobject/qstring.c          | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/include/qapi/qmp/qstring.h b/include/qapi/qmp/qstring.h
index 65c05a9be5..a145c8ca00 100644
--- a/include/qapi/qmp/qstring.h
+++ b/include/qapi/qmp/qstring.h
@@ -27,6 +27,7 @@ QString *qstring_from_str(const char *str);
 QString *qstring_from_substr(const char *str, int start, int end);
 size_t qstring_get_length(const QString *qstring);
 const char *qstring_get_str(const QString *qstring);
+const char *qstring_get_try_str(const QString *qstring);
 void qstring_append_int(QString *qstring, int64_t value);
 void qstring_append(QString *qstring, const char *str);
 void qstring_append_chr(QString *qstring, int c);
diff --git a/qobject/qstring.c b/qobject/qstring.c
index 74182a1c02..7638ab990d 100644
--- a/qobject/qstring.c
+++ b/qobject/qstring.c
@@ -128,6 +128,16 @@ const char *qstring_get_str(const QString *qstring)
     return qstring->string;
 }
 
+/**
+ * qstring_get_try_str(): Return a pointer to the stored string
+ *
+ * NOTE: will return NULL if qstring is not provided.
+ */
+const char *qstring_get_try_str(const QString *qstring)
+{
+    return qstring ? qstring_get_str(qstring) : NULL;
+}
+
 /**
  * qstring_is_equal(): Test whether the two QStrings are equal
  */
-- 
2.14.3