[Qemu-devel] [PATCH v2][ 11/21] qapi: add QMP output visiter

[Michael Roth <mdroth@linux.vnet.ibm.com>]

Type of Visiter class that serves as the inverse of the input visiter:
it takes a series of native C types and uses their values to construct a
corresponding QObject. The command marshaling/dispatcher functions will
use this to convert the output of QMP functions into a QObject that can
be sent over the wire.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 qapi/qmp-output-visiter.c |  180 +++++++++++++++++++++++++++++++++++++++++++++
 qapi/qmp-output-visiter.h |   27 +++++++
 2 files changed, 207 insertions(+), 0 deletions(-)
 create mode 100644 qapi/qmp-output-visiter.c
 create mode 100644 qapi/qmp-output-visiter.h

diff --git a/qapi/qmp-output-visiter.c b/qapi/qmp-output-visiter.c
new file mode 100644
index 0000000..4a7cb36
--- /dev/null
+++ b/qapi/qmp-output-visiter.c
@@ -0,0 +1,180 @@
+#include "qmp-output-visiter.h"
+#include "qemu-queue.h"
+#include "qemu-common.h"
+#include "qemu-objects.h"
+
+typedef struct QStackEntry
+{
+    QObject *value;
+    QTAILQ_ENTRY(QStackEntry) node;
+} QStackEntry;
+
+typedef QTAILQ_HEAD(QStack, QStackEntry) QStack;
+
+struct QmpOutputVisiter
+{
+    Visiter visiter;
+    QStack stack;
+};
+
+#define qmp_output_add(qov, name, value) qmp_output_add_obj(qov, name, QOBJECT(value))
+#define qmp_output_push(qov, value) qmp_output_push_obj(qov, QOBJECT(value))
+
+static QmpOutputVisiter *to_qov(Visiter *v)
+{
+    return container_of(v, QmpOutputVisiter, visiter);
+}
+
+static void qmp_output_push_obj(QmpOutputVisiter *qov, QObject *value)
+{
+    QStackEntry *e = qemu_mallocz(sizeof(*e));
+
+    e->value = value;
+    QTAILQ_INSERT_HEAD(&qov->stack, e, node);
+}
+
+static QObject *qmp_output_pop(QmpOutputVisiter *qov)
+{
+    QStackEntry *e = QTAILQ_FIRST(&qov->stack);
+    QObject *value;
+    QTAILQ_REMOVE(&qov->stack, e, node);
+    value = e->value;
+    qemu_free(e);
+    return value;
+}
+
+static QObject *qmp_output_first(QmpOutputVisiter *qov)
+{
+    QStackEntry *e = QTAILQ_LAST(&qov->stack, QStack);
+    return e->value;
+}
+
+static QObject *qmp_output_last(QmpOutputVisiter *qov)
+{
+    QStackEntry *e = QTAILQ_FIRST(&qov->stack);
+    return e->value;
+}
+
+static void qmp_output_add_obj(QmpOutputVisiter *qov, const char *name, QObject *value)
+{
+    QObject *cur;
+
+    if (QTAILQ_EMPTY(&qov->stack)) {
+        qmp_output_push_obj(qov, value);
+        return;
+    }
+
+    cur = qmp_output_last(qov);
+
+    switch (qobject_type(cur)) {
+    case QTYPE_QDICT:
+        qdict_put_obj(qobject_to_qdict(cur), name, value);
+        break;
+    case QTYPE_QLIST:
+        qlist_append_obj(qobject_to_qlist(cur), value);
+        break;
+    default:
+        qobject_decref(qmp_output_pop(qov));
+        qmp_output_push_obj(qov, value);
+        break;
+    }
+}
+
+static void qmp_output_start_struct(Visiter *v, void **obj, const char *kind, const char *name, Error **errp)
+{
+    QmpOutputVisiter *qov = to_qov(v);
+    QDict *dict = qdict_new();
+
+    qmp_output_add(qov, name, dict);
+    qmp_output_push(qov, dict);
+}
+
+static void qmp_output_end_struct(Visiter *v, Error **errp)
+{
+    QmpOutputVisiter *qov = to_qov(v);
+    qmp_output_pop(qov);
+}
+
+static void qmp_output_start_list(Visiter *v, const char *name, Error **errp)
+{
+    QmpOutputVisiter *qov = to_qov(v);
+    QList *list = qlist_new();
+
+    qmp_output_add(qov, name, list);
+    qmp_output_push(qov, list);
+}
+
+static GenericList *qmp_output_next_list(Visiter *v, GenericList **list, Error **errp)
+{
+    GenericList *retval = *list;
+    *list = retval->next;
+    return retval;
+}
+
+static void qmp_output_end_list(Visiter *v, Error **errp)
+{
+    QmpOutputVisiter *qov = to_qov(v);
+    qmp_output_pop(qov);
+}
+
+static void qmp_output_type_int(Visiter *v, int64_t *obj, const char *name, Error **errp)
+{
+    QmpOutputVisiter *qov = to_qov(v);
+    qmp_output_add(qov, name, qint_from_int(*obj));
+}
+
+static void qmp_output_type_bool(Visiter *v, bool *obj, const char *name, Error **errp)
+{
+    QmpOutputVisiter *qov = to_qov(v);
+    qmp_output_add(qov, name, qbool_from_int(*obj));
+}
+
+static void qmp_output_type_str(Visiter *v, char **obj, const char *name, Error **errp)
+{
+    QmpOutputVisiter *qov = to_qov(v);
+    qmp_output_add(qov, name, qstring_from_str(*obj));
+}
+
+static void qmp_output_type_number(Visiter *v, double *obj, const char *name, Error **errp)
+{
+    QmpOutputVisiter *qov = to_qov(v);
+    qmp_output_add(qov, name, qfloat_from_double(*obj));
+}
+
+static void qmp_output_type_enum(Visiter *v, int *obj, const char *kind, const char *name, Error **errp)
+{
+    int64_t value = *obj;
+    qmp_output_type_int(v, &value, name, errp);
+}
+
+QObject *qmp_output_get_qobject(QmpOutputVisiter *qov)
+{
+    return qmp_output_first(qov);
+}
+
+Visiter *qmp_output_get_visiter(QmpOutputVisiter *v)
+{
+    return &v->visiter;
+}
+
+QmpOutputVisiter *qmp_output_visiter_new(void)
+{
+    QmpOutputVisiter *v;
+
+    v = qemu_mallocz(sizeof(*v));
+
+    v->visiter.start_struct = qmp_output_start_struct;
+    v->visiter.end_struct = qmp_output_end_struct;
+    v->visiter.start_list = qmp_output_start_list;
+    v->visiter.next_list = qmp_output_next_list;
+    v->visiter.end_list = qmp_output_end_list;
+    v->visiter.type_enum = qmp_output_type_enum;
+    v->visiter.type_int = qmp_output_type_int;
+    v->visiter.type_bool = qmp_output_type_bool;
+    v->visiter.type_str = qmp_output_type_str;
+    v->visiter.type_number = qmp_output_type_number;
+
+    QTAILQ_INIT(&v->stack);
+
+    return v;
+}
diff --git a/qapi/qmp-output-visiter.h b/qapi/qmp-output-visiter.h
new file mode 100644
index 0000000..b04ab02
--- /dev/null
+++ b/qapi/qmp-output-visiter.h
@@ -0,0 +1,27 @@
+/*
+ * Output Visiter
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef QMP_OUTPUT_VISITER_H
+#define QMP_OUTPUT_VISITER_H
+
+#include "qapi-visit-core.h"
+#include "qobject.h"
+
+typedef struct QmpOutputVisiter QmpOutputVisiter;
+
+QmpOutputVisiter *qmp_output_visiter_new(void);
+
+QObject *qmp_output_get_qobject(QmpOutputVisiter *v);
+Visiter *qmp_output_get_visiter(QmpOutputVisiter *v);
+
+#endif
-- 
1.7.0.4