util: add iterators for QemuOpts values

To iterate over all QemuOpts currently requires using a callback
function which is inconvenient for control flow. Add support for
using iterator functions more directly

  QemuOptsIter iter;
  QemuOpt *opt;

  qemu_opts_iter_init(&iter, opts, "repeated-key");
  while ((opt = qemu_opts_iter_next(&iter)) != NULL) {
      ....do something...
  }

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170203120649.15637-8-berrange@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/qemu/option.h b/include/qemu/option.h
index 1f9e3f939d..e786df0cfa 100644
--- a/include/qemu/option.h
+++ b/include/qemu/option.h
@@ -100,6 +100,15 @@ typedef int (*qemu_opt_loopfunc)(void *opaque,
 int qemu_opt_foreach(QemuOpts *opts, qemu_opt_loopfunc func, void *opaque,
                      Error **errp);
 
+typedef struct {
+    QemuOpts *opts;
+    QemuOpt *opt;
+    const char *name;
+} QemuOptsIter;
+
+void qemu_opt_iter_init(QemuOptsIter *iter, QemuOpts *opts, const char *name);
+const char *qemu_opt_iter_next(QemuOptsIter *iter);
+
 QemuOpts *qemu_opts_find(QemuOptsList *list, const char *id);
 QemuOpts *qemu_opts_create(QemuOptsList *list, const char *id,
                            int fail_if_exists, Error **errp);