qapi: add QAPI dealloc visitor

Type of Visitor class that can be passed into a qapi-generated C
type's visitor function to free() any heap-allocated data types.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@gmail.com>

Makefile.objs

@@ -375,7 +375,7 @@ libcacard-y = cac.o event.o vcard.o vreader.o vcard_emul_nss.o vcard_emul_type.o
 ######################################################################
 # qapi
 
-qapi-nested-y = qapi-visit-core.o qmp-input-visitor.o qmp-output-visitor.o
+qapi-nested-y = qapi-visit-core.o qmp-input-visitor.o qmp-output-visitor.o qapi-dealloc-visitor.o
 qapi-obj-y = $(addprefix qapi/, $(qapi-nested-y))
 
 vl.o: QEMU_CFLAGS+=$(GPROF_CFLAGS)

qapi/qapi-dealloc-visitor.c

+/*
+ * 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 "qemu-objects.h"
+
+typedef struct StackEntry
+{
+    void *value;
+    QTAILQ_ENTRY(StackEntry) node;
+} StackEntry;
+
+struct QapiDeallocVisitor
+{
+    Visitor visitor;
+    QTAILQ_HEAD(, StackEntry) stack;
+};
+
+static QapiDeallocVisitor *to_qov(Visitor *v)
+{
+    return container_of(v, QapiDeallocVisitor, visitor);
+}
+
+static void qapi_dealloc_push(QapiDeallocVisitor *qov, void *value)
+{
+    StackEntry *e = qemu_mallocz(sizeof(*e));
+
+    e->value = value;
+    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;
+    qemu_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) {
+        qemu_free(*obj);
+    }
+}
+
+static void qapi_dealloc_start_list(Visitor *v, const char *name, Error **errp)
+{
+}
+
+static GenericList *qapi_dealloc_next_list(Visitor *v, GenericList **list,
+                                           Error **errp)
+{
+    GenericList *retval = *list;
+    qemu_free(retval->value);
+    *list = retval->next;
+    return retval;
+}
+
+static void qapi_dealloc_end_list(Visitor *v, Error **errp)
+{
+}
+
+static void qapi_dealloc_type_str(Visitor *v, char **obj, const char *name,
+                                  Error **errp)
+{
+    if (obj) {
+        qemu_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_enum(Visitor *v, int *obj, const char *strings[],
+                                   const char *kind, const char *name,
+                                   Error **errp)
+{
+}
+
+Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v)
+{
+    return &v->visitor;
+}
+
+void qapi_dealloc_visitor_cleanup(QapiDeallocVisitor *v)
+{
+    qemu_free(v);
+}
+
+QapiDeallocVisitor *qapi_dealloc_visitor_new(void)
+{
+    QapiDeallocVisitor *v;
+
+    v = qemu_mallocz(sizeof(*v));
+
+    v->visitor.start_struct = qapi_dealloc_start_struct;
+    v->visitor.end_struct = qapi_dealloc_end_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;
+
+    QTAILQ_INIT(&v->stack);
+
+    return v;
+}

qapi/qapi-dealloc-visitor.h

+/*
+ * 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.
+ *
+ */
+
+#ifndef QAPI_DEALLOC_VISITOR_H
+#define QAPI_DEALLOC_VISITOR_H
+
+#include "qapi-visit-core.h"
+
+typedef struct QapiDeallocVisitor QapiDeallocVisitor;
+
+QapiDeallocVisitor *qapi_dealloc_visitor_new(void);
+void qapi_dealloc_visitor_cleanup(QapiDeallocVisitor *d);
+
+Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v);
+
+#endif