import

qemu/qapi/qapi-dealloc-visitor.c

@@ -0,0 +1,224 @@
+/*
+ * Dealloc Visitor
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Michael Roth   <mdroth@linux.vnet.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.
+ *
+ */
+
+#include "qapi/dealloc-visitor.h"
+#include "qemu/queue.h"
+#include "qemu-common.h"
+#include "qapi/qmp/types.h"
+#include "qapi/visitor-impl.h"
+
+typedef struct StackEntry
+{
+    void *value;
+    bool is_list_head;
+    QTAILQ_ENTRY(StackEntry) node;
+} StackEntry;
+
+struct QapiDeallocVisitor
+{
+    Visitor visitor;
+    QTAILQ_HEAD(, StackEntry) stack;
+    bool is_list_head;
+};
+
+static QapiDeallocVisitor *to_qov(Visitor *v)
+{
+    return container_of(v, QapiDeallocVisitor, visitor);
+}
+
+static void qapi_dealloc_push(QapiDeallocVisitor *qov, void *value)
+{
+    StackEntry *e = g_malloc0(sizeof(*e));
+
+    e->value = value;
+
+    /* see if we're just pushing a list head tracker */
+    if (value == NULL) {
+        e->is_list_head = true;
+    }
+    QTAILQ_INSERT_HEAD(&qov->stack, e, node);
+}
+
+static void *qapi_dealloc_pop(QapiDeallocVisitor *qov)
+{
+    StackEntry *e = QTAILQ_FIRST(&qov->stack);
+    QObject *value;
+    QTAILQ_REMOVE(&qov->stack, e, node);
+    value = e->value;
+    g_free(e);
+    return value;
+}
+
+static void qapi_dealloc_start_struct(Visitor *v, void **obj, const char *kind,
+                                      const char *name, size_t unused,
+                                      Error **errp)
+{
+    QapiDeallocVisitor *qov = to_qov(v);
+    qapi_dealloc_push(qov, obj);
+}
+
+static void qapi_dealloc_end_struct(Visitor *v, Error **errp)
+{
+    QapiDeallocVisitor *qov = to_qov(v);
+    void **obj = qapi_dealloc_pop(qov);
+    if (obj) {
+        g_free(*obj);
+    }
+}
+
+static void qapi_dealloc_start_implicit_struct(Visitor *v,
+                                               void **obj,
+                                               size_t size,
+                                               Error **errp)
+{
+    QapiDeallocVisitor *qov = to_qov(v);
+    qapi_dealloc_push(qov, obj);
+}
+
+static void qapi_dealloc_end_implicit_struct(Visitor *v, Error **errp)
+{
+    QapiDeallocVisitor *qov = to_qov(v);
+    void **obj = qapi_dealloc_pop(qov);
+    if (obj) {
+        g_free(*obj);
+    }
+}
+
+static void qapi_dealloc_start_list(Visitor *v, const char *name, Error **errp)
+{
+    QapiDeallocVisitor *qov = to_qov(v);
+    qapi_dealloc_push(qov, NULL);
+}
+
+static GenericList *qapi_dealloc_next_list(Visitor *v, GenericList **listp,
+                                           Error **errp)
+{
+    GenericList *list = *listp;
+    QapiDeallocVisitor *qov = to_qov(v);
+    StackEntry *e = QTAILQ_FIRST(&qov->stack);
+
+    if (e && e->is_list_head) {
+        e->is_list_head = false;
+        return list;
+    }
+
+    if (list) {
+        list = list->next;
+        g_free(*listp);
+        return list;
+    }
+
+    return NULL;
+}
+
+static void qapi_dealloc_end_list(Visitor *v, Error **errp)
+{
+    QapiDeallocVisitor *qov = to_qov(v);
+    void *obj = qapi_dealloc_pop(qov);
+    assert(obj == NULL); /* should've been list head tracker with no payload */
+}
+
+static void qapi_dealloc_type_str(Visitor *v, char **obj, const char *name,
+                                  Error **errp)
+{
+    if (obj) {
+        g_free(*obj);
+    }
+}
+
+static void qapi_dealloc_type_int(Visitor *v, int64_t *obj, const char *name,
+                                  Error **errp)
+{
+}
+
+static void qapi_dealloc_type_bool(Visitor *v, bool *obj, const char *name,
+                                   Error **errp)
+{
+}
+
+static void qapi_dealloc_type_number(Visitor *v, double *obj, const char *name,
+                                     Error **errp)
+{
+}
+
+static void qapi_dealloc_type_size(Visitor *v, uint64_t *obj, const char *name,
+                                   Error **errp)
+{
+}
+
+static void qapi_dealloc_type_enum(Visitor *v, int *obj, const char *strings[],
+                                   const char *kind, const char *name,
+                                   Error **errp)
+{
+}
+
+/* If there's no data present, the dealloc visitor has nothing to free.
+ * Thus, indicate to visitor code that the subsequent union fields can
+ * be skipped. This is not an error condition, since the cleanup of the
+ * rest of an object can continue unhindered, so leave errp unset in
+ * these cases.
+ *
+ * NOTE: In cases where we're attempting to deallocate an object that
+ * may have missing fields, the field indicating the union type may
+ * be missing. In such a case, it's possible we don't have enough
+ * information to differentiate data_present == false from a case where
+ * data *is* present but happens to be a scalar with a value of 0.
+ * This is okay, since in the case of the dealloc visitor there's no
+ * work that needs to done in either situation.
+ *
+ * The current inability in QAPI code to more thoroughly verify a union
+ * type in such cases will likely need to be addressed if we wish to
+ * implement this interface for other types of visitors in the future,
+ * however.
+ */
+static bool qapi_dealloc_start_union(Visitor *v, bool data_present,
+                                     Error **errp)
+{
+    return data_present;
+}
+
+Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v)
+{
+    return &v->visitor;
+}
+
+void qapi_dealloc_visitor_cleanup(QapiDeallocVisitor *v)
+{
+    g_free(v);
+}
+
+QapiDeallocVisitor *qapi_dealloc_visitor_new(void)
+{
+    QapiDeallocVisitor *v;
+
+    v = g_malloc0(sizeof(*v));
+
+    v->visitor.start_struct = qapi_dealloc_start_struct;
+    v->visitor.end_struct = qapi_dealloc_end_struct;
+    v->visitor.start_implicit_struct = qapi_dealloc_start_implicit_struct;
+    v->visitor.end_implicit_struct = qapi_dealloc_end_implicit_struct;
+    v->visitor.start_list = qapi_dealloc_start_list;
+    v->visitor.next_list = qapi_dealloc_next_list;
+    v->visitor.end_list = qapi_dealloc_end_list;
+    v->visitor.type_enum = qapi_dealloc_type_enum;
+    v->visitor.type_int = qapi_dealloc_type_int;
+    v->visitor.type_bool = qapi_dealloc_type_bool;
+    v->visitor.type_str = qapi_dealloc_type_str;
+    v->visitor.type_number = qapi_dealloc_type_number;
+    v->visitor.type_size = qapi_dealloc_type_size;
+    v->visitor.start_union = qapi_dealloc_start_union;
+
+    QTAILQ_INIT(&v->stack);
+
+    return v;
+}