--- /dev/null
+/*
+ * virobject.c: libvirt reference counted object
+ *
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <config.h>
+
+#include "virobject.h"
+#include "threads.h"
+#include "memory.h"
+#include "viratomic.h"
+#include "virterror_internal.h"
+#include "logging.h"
+
+#define VIR_FROM_THIS VIR_FROM_NONE
+
+static unsigned int magicCounter = 0xCAFE0000;
+
+struct _virClass {
+ unsigned int magic;
+ const char *name;
+ size_t objectSize;
+
+ virObjectDisposeCallback dispose;
+};
+
+
+/**
+ * virClassNew:
+ * @name: the class name
+ * @objectSize: total size of the object struct
+ * @dispose: callback to run to free object fields
+ *
+ * Register a new object class with @name. The @objectSize
+ * should give the total size of the object struct, which
+ * is expected to have a 'virObject object;' field as its
+ * first member. When the last reference on the object is
+ * released, the @dispose callback will be invoked to free
+ * memory of the object fields
+ *
+ * Returns a new class instance
+ */
+virClassPtr virClassNew(const char *name,
+ size_t objectSize,
+ virObjectDisposeCallback dispose)
+{
+ virClassPtr klass;
+
+ if (VIR_ALLOC(klass) < 0)
+ goto no_memory;
+
+ if (!(klass->name = strdup(name)))
+ goto no_memory;
+ klass->magic = virAtomicIntInc(&magicCounter);
+ klass->objectSize = objectSize;
+ klass->dispose = dispose;
+
+ return klass;
+
+no_memory:
+ VIR_FREE(klass);
+ virReportOOMError();
+ return NULL;
+}
+
+
+/**
+ * virObjectNew:
+ * @klass: the klass of object to create
+ *
+ * Allocates a new object of type @klass. The returned
+ * object will be an instance of "virObjectPtr", which
+ * can be cast to the struct associated with @klass.
+ *
+ * The initial reference count of the object will be 1.
+ *
+ * Returns the new object
+ */
+void *virObjectNew(virClassPtr klass)
+{
+ virObjectPtr obj = NULL;
+ char *somebytes;
+
+ if (VIR_ALLOC_N(somebytes, klass->objectSize) < 0) {
+ virReportOOMError();
+ return NULL;
+ }
+ obj = (virObjectPtr)somebytes;
+
+ obj->magic = klass->magic;
+ obj->klass = klass;
+ virAtomicIntSet(&obj->refs, 1);
+
+ PROBE(OBJECT_NEW, "obj=%p classname=%s", obj, obj->klass->name);
+
+ return obj;
+}
+
+
+/**
+ * virObjectUnref:
+ * @anyobj: any instance of virObjectPtr
+ *
+ * Decrement the reference count on @anyobj and if
+ * it hits zero, runs the "dispose" callback associated
+ * with the object class and frees @anyobj.
+ *
+ * Returns true if the remaining reference count is
+ * non-zero, false if the object was disposed of
+ */
+bool virObjectUnref(void *anyobj)
+{
+ virObjectPtr obj = anyobj;
+
+ if (!obj)
+ return false;
+
+ bool lastRef = virAtomicIntDecAndTest(&obj->refs);
+ PROBE(OBJECT_UNREF, "obj=%p", obj);
+ if (lastRef) {
+ PROBE(OBJECT_DISPOSE, "obj=%p", obj);
+ if (obj->klass->dispose)
+ obj->klass->dispose(obj);
+
+ /* Clear & poison object */
+ memset(obj, 0, obj->klass->objectSize);
+ obj->magic = 0xDEADBEEF;
+ obj->klass = (void*)0xDEADBEEF;
+ VIR_FREE(obj);
+ }
+
+ return !lastRef;
+}
+
+
+/**
+ * virObjectRef:
+ * @anyobj: any instance of virObjectPtr
+ *
+ * Increment the reference count on @anyobj and return
+ * the same pointer
+ *
+ * Returns @anyobj
+ */
+void *virObjectRef(void *anyobj)
+{
+ virObjectPtr obj = anyobj;
+
+ if (!obj)
+ return NULL;
+ virAtomicIntInc(&obj->refs);
+ PROBE(OBJECT_REF, "obj=%p", obj);
+ return anyobj;
+}
+
+
+/**
+ * virObjectIsClass:
+ * @anyobj: any instance of virObjectPtr
+ * @klass: the class to check
+ *
+ * Checks whether @anyobj is an instance of
+ * @klass
+ *
+ * Returns true if @anyobj is an instance of @klass
+ */
+bool virObjectIsClass(void *anyobj,
+ virClassPtr klass)
+{
+ virObjectPtr obj = anyobj;
+ return obj != NULL && (obj->magic == klass->magic) && (obj->klass == klass);
+}
+
+
+/**
+ * virClassName:
+ * @klass: the object class
+ *
+ * Returns the name of @klass
+ */
+const char *virClassName(virClassPtr klass)
+{
+ return klass->name;
+}
+
+
+/**
+ * virObjectFreeCallback:
+ * @opaque: a pointer to a virObject instance
+ *
+ * Provides identical functionality to virObjectUnref,
+ * but with the signature matching the virFreeCallback
+ * typedef.
+ */
+void virObjectFreeCallback(void *opaque)
+{
+ virObjectUnref(opaque);
+}
--- /dev/null
+/*
+ * virobject.h: libvirt reference counted object
+ *
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef __VIR_OBJECT_H__
+# define __VIR_OBJECT_H__
+
+# include "internal.h"
+
+typedef struct _virClass virClass;
+typedef virClass *virClassPtr;
+
+typedef struct _virObject virObject;
+typedef virObject *virObjectPtr;
+
+typedef void (*virObjectDisposeCallback)(void *obj);
+
+struct _virObject {
+ unsigned int magic;
+ int refs;
+ virClassPtr klass;
+};
+
+virClassPtr virClassNew(const char *name,
+ size_t objectSize,
+ virObjectDisposeCallback dispose)
+ ATTRIBUTE_NONNULL(1);
+
+const char *virClassName(virClassPtr klass)
+ ATTRIBUTE_NONNULL(1);
+
+void *virObjectNew(virClassPtr klass)
+ ATTRIBUTE_NONNULL(1);
+bool virObjectUnref(void *obj);
+void *virObjectRef(void *obj);
+
+bool virObjectIsClass(void *obj,
+ virClassPtr klass)
+ ATTRIBUTE_NONNULL(2);
+
+void virObjectFreeCallback(void *opaque);
+
+#endif /* __VIR_OBJECT_H */
projects / libvirt.git / commitdiff