Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 204 insertions, 0 deletions

diff --git a/qapi/qapi-clone-visitor.c b/qapi/qapi-clone-visitor.c
new file mode 100644
index 000000000..c45c5caa3
--- /dev/null
+++ b/qapi/qapi-clone-visitor.c
@@ -0,0 +1,204 @@
+/*
+ * Copy one QAPI object to another
+ *
+ * Copyright (C) 2016 Red Hat, Inc.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/clone-visitor.h"
+#include "qapi/visitor-impl.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qnull.h"
+
+struct QapiCloneVisitor {
+    Visitor visitor;
+    size_t depth;
+};
+
+static QapiCloneVisitor *to_qcv(Visitor *v)
+{
+    return container_of(v, QapiCloneVisitor, visitor);
+}
+
+static bool qapi_clone_start_struct(Visitor *v, const char *name, void **obj,
+                                    size_t size, Error **errp)
+{
+    QapiCloneVisitor *qcv = to_qcv(v);
+
+    if (!obj) {
+        assert(qcv->depth);
+        /* Only possible when visiting an alternate's object
+         * branch. Nothing further to do here, since the earlier
+         * visit_start_alternate() already copied memory. */
+        return true;
+    }
+
+    *obj = g_memdup(*obj, size);
+    qcv->depth++;
+    return true;
+}
+
+static void qapi_clone_end(Visitor *v, void **obj)
+{
+    QapiCloneVisitor *qcv = to_qcv(v);
+
+    assert(qcv->depth);
+    if (obj) {
+        qcv->depth--;
+    }
+}
+
+static bool qapi_clone_start_list(Visitor *v, const char *name,
+                                  GenericList **listp, size_t size,
+                                  Error **errp)
+{
+    return qapi_clone_start_struct(v, name, (void **)listp, size, errp);
+}
+
+static GenericList *qapi_clone_next_list(Visitor *v, GenericList *tail,
+                                         size_t size)
+{
+    QapiCloneVisitor *qcv = to_qcv(v);
+
+    assert(qcv->depth);
+    /* Unshare the tail of the list cloned by g_memdup() */
+    tail->next = g_memdup(tail->next, size);
+    return tail->next;
+}
+
+static bool qapi_clone_start_alternate(Visitor *v, const char *name,
+                                       GenericAlternate **obj, size_t size,
+                                       Error **errp)
+{
+    return qapi_clone_start_struct(v, name, (void **)obj, size, errp);
+}
+
+static bool qapi_clone_type_int64(Visitor *v, const char *name, int64_t *obj,
+                                  Error **errp)
+{
+    QapiCloneVisitor *qcv = to_qcv(v);
+
+    assert(qcv->depth);
+    /* Value was already cloned by g_memdup() */
+    return true;
+}
+
+static bool qapi_clone_type_uint64(Visitor *v, const char *name,
+                                   uint64_t *obj, Error **errp)
+{
+    QapiCloneVisitor *qcv = to_qcv(v);
+
+    assert(qcv->depth);
+    /* Value was already cloned by g_memdup() */
+    return true;
+}
+
+static bool qapi_clone_type_bool(Visitor *v, const char *name, bool *obj,
+                                 Error **errp)
+{
+    QapiCloneVisitor *qcv = to_qcv(v);
+
+    assert(qcv->depth);
+    /* Value was already cloned by g_memdup() */
+    return true;
+}
+
+static bool qapi_clone_type_str(Visitor *v, const char *name, char **obj,
+                                Error **errp)
+{
+    QapiCloneVisitor *qcv = to_qcv(v);
+
+    assert(qcv->depth);
+    /*
+     * Pointer was already cloned by g_memdup; create fresh copy.
+     * Note that as long as qobject-output-visitor accepts NULL instead of
+     * "", then we must do likewise. However, we want to obey the
+     * input visitor semantics of never producing NULL when the empty
+     * string is intended.
+     */
+    *obj = g_strdup(*obj ?: "");
+    return true;
+}
+
+static bool qapi_clone_type_number(Visitor *v, const char *name, double *obj,
+                                   Error **errp)
+{
+    QapiCloneVisitor *qcv = to_qcv(v);
+
+    assert(qcv->depth);
+    /* Value was already cloned by g_memdup() */
+    return true;
+}
+
+static bool qapi_clone_type_null(Visitor *v, const char *name, QNull **obj,
+                                 Error **errp)
+{
+    QapiCloneVisitor *qcv = to_qcv(v);
+
+    assert(qcv->depth);
+    *obj = qnull();
+    return true;
+}
+
+static void qapi_clone_free(Visitor *v)
+{
+    g_free(v);
+}
+
+static Visitor *qapi_clone_visitor_new(void)
+{
+    QapiCloneVisitor *v;
+
+    v = g_malloc0(sizeof(*v));
+
+    v->visitor.type = VISITOR_CLONE;
+    v->visitor.start_struct = qapi_clone_start_struct;
+    v->visitor.end_struct = qapi_clone_end;
+    v->visitor.start_list = qapi_clone_start_list;
+    v->visitor.next_list = qapi_clone_next_list;
+    v->visitor.end_list = qapi_clone_end;
+    v->visitor.start_alternate = qapi_clone_start_alternate;
+    v->visitor.end_alternate = qapi_clone_end;
+    v->visitor.type_int64 = qapi_clone_type_int64;
+    v->visitor.type_uint64 = qapi_clone_type_uint64;
+    v->visitor.type_bool = qapi_clone_type_bool;
+    v->visitor.type_str = qapi_clone_type_str;
+    v->visitor.type_number = qapi_clone_type_number;
+    v->visitor.type_null = qapi_clone_type_null;
+    v->visitor.free = qapi_clone_free;
+
+    return &v->visitor;
+}
+
+void *qapi_clone(const void *src, bool (*visit_type)(Visitor *, const char *,
+                                                     void **, Error **))
+{
+    Visitor *v;
+    void *dst = (void *) src; /* Cast away const */
+
+    if (!src) {
+        return NULL;
+    }
+
+    v = qapi_clone_visitor_new();
+    visit_type(v, NULL, &dst, &error_abort);
+    visit_free(v);
+    return dst;
+}
+
+void qapi_clone_members(void *dst, const void *src, size_t sz,
+                        bool (*visit_type_members)(Visitor *, void *,
+                                                   Error **))
+{
+    Visitor *v;
+
+    v = qapi_clone_visitor_new();
+    memcpy(dst, src, sz);
+    to_qcv(v)->depth++;
+    visit_type_members(v, dst, &error_abort);
+    visit_free(v);
+}