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[Qemu-devel] [PATCH 01/29] Introduce QObject
From: |
Luiz Capitulino |
Subject: |
[Qemu-devel] [PATCH 01/29] Introduce QObject |
Date: |
Wed, 19 Aug 2009 20:07:32 -0300 |
This commit introduces the qobject.h header file, it contains
basic QObject definitions and helper macros.
Signed-off-by: Luiz Capitulino <address@hidden>
---
qobject.h | 110 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 110 insertions(+), 0 deletions(-)
create mode 100644 qobject.h
diff --git a/qobject.h b/qobject.h
new file mode 100644
index 0000000..c23b5f3
--- /dev/null
+++ b/qobject.h
@@ -0,0 +1,110 @@
+/*
+ * QEMU Object Model.
+ *
+ * Based on ideas by Avi Kivity <address@hidden>
+ *
+ * Copyright (C) 2009 Red Hat Inc.
+ *
+ * Authors:
+ * Luiz Capitulino <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ *
+ * QObject Reference Counts
+ * ------------------------
+ *
+ * The concept of reference counting used here is the same of Python, ie,
+ * 'ownership of references'.
+ *
+ * Basic terminology:
+ *
+ * - Owning a reference: means being responsible for calling QDECREF()
+ * when the reference is no longer needed
+ *
+ * - New reference: means that the caller is now the owner of a reference,
+ * for example, if you call a function that returns a 'new reference' you
+ * must call QDECREF() when you are done
+ *
+ * - Borrowing a reference: nothing needs to be done, you are not the
+ * owner of the reference
+ *
+ * - Stealing a reference: when you pass a reference to a function that
+ * 'steals a reference' this function assumes that it now owns that
+ * reference
+ */
+#ifndef QOBJECT_H
+#define QOBJECT_H
+
+#include <stddef.h>
+#include <assert.h>
+
+typedef enum {
+ QTYPE_NONE,
+} qtype_code;
+
+struct QObject;
+
+typedef struct QType {
+ qtype_code code;
+ void (*destroy)(struct QObject *);
+} QType;
+
+typedef struct QObject {
+ const QType *type;
+ size_t refcnt;
+} QObject;
+
+/* Type definitions must include this */
+#define QType_HEAD \
+ QObject base;
+
+/* Get the QObject part of a type */
+#define QOBJECT(obj) (&obj->base)
+
+/* High-level interface for qobject_incref() */
+#define QINCREF(qtype) \
+ assert(qtype != NULL); \
+ qobject_incref(QOBJECT(qtype))
+
+/* High-level interface for qobject_decref() */
+#define QDECREF(qtype) \
+ assert(qtype != NULL); \
+ qobject_decref(QOBJECT(qtype))
+
+/* Initialize a type to default values */
+#define QOBJECT_INIT(qtype, qtype_type) \
+ qtype->base.refcnt = 1; \
+ qtype->base.type = qtype_type
+
+/**
+ * qobject_incref(): Increment QObject's reference count
+ */
+static inline void qobject_incref(QObject *obj)
+{
+ obj->refcnt++;
+}
+
+/**
+ * qobject_decref(): Decrement QObject's reference count, deallocate
+ * when it reaches zero
+ */
+static inline void qobject_decref(QObject *obj)
+{
+ if (--obj->refcnt == 0) {
+ assert(obj->type != NULL);
+ assert(obj->type->destroy != NULL);
+ obj->type->destroy(obj);
+ }
+}
+
+/**
+ * qobject_type(): Return the QObject's type
+ */
+static inline qtype_code qobject_type(const QObject *obj)
+{
+ assert(obj->type != NULL);
+ return obj->type->code;
+}
+
+#endif /* QOBJECT_H */
--
1.6.4.67.gea5b1
[Qemu-devel] Re: [PATCH 01/29] Introduce QObject, Paolo Bonzini, 2009/08/20
[Qemu-devel] [PATCH 02/29] Introduce QInt, Luiz Capitulino, 2009/08/19