Patchwork [02/15] Introduce QList

login
register
mail settings
Submitter Luiz Capitulino
Date Oct. 7, 2009, 12:26 a.m.
Message ID <1254875232-25012-3-git-send-email-lcapitulino@redhat.com>
Download mbox | patch
Permalink /patch/35173/
State Changes Requested
Headers show

Comments

Luiz Capitulino - Oct. 7, 2009, 12:26 a.m.
QList is a high-level data type that can be used to store QObjects
in a singly-linked list.

The following functions are available:

- qlist_new()    Create a new QList
- qlist_append() Append a QObject to the list
- qlist_iter()   Iterate over stored QObjects

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
---
 Makefile  |    2 +-
 qlist.c   |  100 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 qlist.h   |   27 ++++++++++++++++
 qobject.h |    1 +
 4 files changed, 129 insertions(+), 1 deletions(-)
 create mode 100644 qlist.c
 create mode 100644 qlist.h
Anthony Liguori - Oct. 7, 2009, 1:37 a.m.
Luiz Capitulino wrote:
> QList is a high-level data type that can be used to store QObjects
> in a singly-linked list.
>
> The following functions are available:
>
> - qlist_new()    Create a new QList
> - qlist_append() Append a QObject to the list
> - qlist_iter()   Iterate over stored QObjects
>
> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
> ---
>  Makefile  |    2 +-
>  qlist.c   |  100 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  qlist.h   |   27 ++++++++++++++++
>  qobject.h |    1 +
>  4 files changed, 129 insertions(+), 1 deletions(-)
>  create mode 100644 qlist.c
>  create mode 100644 qlist.h
>   
<snip>
> +/**
> + * qlist_iter(): Iterate over all the list's stored values.
> + *
> + * This function allows the user to provide an iterator, which will be
> + * called for each stored value in the list.
> + */
> +void qlist_iter(const QList *qlist,
> +                void (*iter)(QObject *obj, void *opaque), void *opaque)
> +{
> +    QListEntry *entry;
> +
> +    QTAILQ_FOREACH(entry, &qlist->head, next)
> +        iter(entry->value, opaque);
> +}
> +
> +/**
> + * qobject_to_qlist(): Convert a QObject into a QList
> + */
> +QList *qobject_to_qlist(const QObject *obj)
> +{
> +    if (qobject_type(obj) != QTYPE_QLIST)
> +        return NULL;
> +
> +    return container_of(obj, QList, base);
> +}
>   

Missing {} around ifs.

> +
> +/**
> + * qlist_destroy_obj(): Free all the memory allocated by a QList
> + */
> +static void qlist_destroy_obj(QObject *obj)
> +{
> +    QList *qlist;
> +    QListEntry *entry, *next_entry;
> +
> +    assert(obj != NULL);
>   

Usually accepting NULL in a free function makes for nicer exit paths in 
function.

> +    qlist = qobject_to_qlist(obj);
> +
> +    QTAILQ_FOREACH_SAFE(entry, &qlist->head, next, next_entry) {
> +        QTAILQ_REMOVE(&qlist->head, entry, next);
> +        qobject_decref(entry->value);
> +        qemu_free(entry);
> +    }
> +
> +    qemu_free(qlist);
> +}
> +
> +static const QType qlist_type = {
> +    .code = QTYPE_QLIST,
> +    .destroy = qlist_destroy_obj,
> +};
>   

Forward definitions of statics usually indicate code motion is in 
order.  In this case, I think it's probably a good idea as my first 
reaction to this was, gees, this has to be dead code since it's a static 
at the end of a file.

> diff --git a/qlist.h b/qlist.h
> new file mode 100644
> index 0000000..b38786e
> --- /dev/null
> +++ b/qlist.h
> @@ -0,0 +1,27 @@
>   

Missing copyright/license.

> +#ifndef QLIST
> +#define QLIST
>   

Should probably at least do QLIST_H to avoid namespace polution.
Luiz Capitulino - Oct. 7, 2009, 12:48 p.m.
On Tue, 06 Oct 2009 20:37:43 -0500
Anthony Liguori <aliguori@us.ibm.com> wrote:

> Luiz Capitulino wrote:

[...]

> > +/**
> > + * qlist_destroy_obj(): Free all the memory allocated by a QList
> > + */
> > +static void qlist_destroy_obj(QObject *obj)
> > +{
> > +    QList *qlist;
> > +    QListEntry *entry, *next_entry;
> > +
> > +    assert(obj != NULL);
> >   
> 
> Usually accepting NULL in a free function makes for nicer exit paths in 
> function.

 The destroy_obj() functions are always called by qobject_decref()
and it will never pass a NULL qobject.

 But qobject_decref() accepts NULL.

 I've applied the other changes, some of them also need to be done
in the others data types (will send patches).

Patch

diff --git a/Makefile b/Makefile
index c552739..17bcbe4 100644
--- a/Makefile
+++ b/Makefile
@@ -100,7 +100,7 @@  obj-y += buffered_file.o migration.o migration-tcp.o net.o qemu-sockets.o
 obj-y += qemu-char.o aio.o net-checksum.o savevm.o
 obj-y += msmouse.o ps2.o
 obj-y += qdev.o qdev-properties.o ssi.o
-obj-y += qint.o qstring.o qdict.o qemu-config.o
+obj-y += qint.o qstring.o qdict.o qlist.o qemu-config.o
 
 obj-$(CONFIG_BRLAPI) += baum.o
 obj-$(CONFIG_WIN32) += tap-win32.o
diff --git a/qlist.c b/qlist.c
new file mode 100644
index 0000000..9c753ce
--- /dev/null
+++ b/qlist.c
@@ -0,0 +1,100 @@ 
+/*
+ * QList data type.
+ *
+ * Copyright (C) 2009 Red Hat Inc.
+ *
+ * Authors:
+ *  Luiz Capitulino <lcapitulino@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "qlist.h"
+#include "qobject.h"
+#include "qemu-queue.h"
+#include "qemu-common.h"
+
+static const QType qlist_type;
+ 
+/**
+ * qlist_new(): Create a new QList
+ *
+ * Return strong reference.
+ */
+QList *qlist_new(void)
+{
+    QList *qlist;
+
+    qlist = qemu_malloc(sizeof(*qlist));
+    QTAILQ_INIT(&qlist->head);
+    QOBJECT_INIT(qlist, &qlist_type);
+
+    return qlist;
+}
+
+/**
+ * qlist_append_obj(): Append an QObject into QList
+ *
+ * NOTE: ownership of 'value' is transferred to the QList
+ */
+void qlist_append_obj(QList *qlist, QObject *value)
+{
+    QListEntry *entry;
+
+    entry = qemu_malloc(sizeof(*entry));
+    entry->value = value;
+
+    QTAILQ_INSERT_TAIL(&qlist->head, entry, next);
+}
+
+/**
+ * qlist_iter(): Iterate over all the list's stored values.
+ *
+ * This function allows the user to provide an iterator, which will be
+ * called for each stored value in the list.
+ */
+void qlist_iter(const QList *qlist,
+                void (*iter)(QObject *obj, void *opaque), void *opaque)
+{
+    QListEntry *entry;
+
+    QTAILQ_FOREACH(entry, &qlist->head, next)
+        iter(entry->value, opaque);
+}
+
+/**
+ * qobject_to_qlist(): Convert a QObject into a QList
+ */
+QList *qobject_to_qlist(const QObject *obj)
+{
+    if (qobject_type(obj) != QTYPE_QLIST)
+        return NULL;
+
+    return container_of(obj, QList, base);
+}
+
+/**
+ * qlist_destroy_obj(): Free all the memory allocated by a QList
+ */
+static void qlist_destroy_obj(QObject *obj)
+{
+    QList *qlist;
+    QListEntry *entry, *next_entry;
+
+    assert(obj != NULL);
+    qlist = qobject_to_qlist(obj);
+
+    QTAILQ_FOREACH_SAFE(entry, &qlist->head, next, next_entry) {
+        QTAILQ_REMOVE(&qlist->head, entry, next);
+        qobject_decref(entry->value);
+        qemu_free(entry);
+    }
+
+    qemu_free(qlist);
+}
+
+static const QType qlist_type = {
+    .code = QTYPE_QLIST,
+    .destroy = qlist_destroy_obj,
+};
diff --git a/qlist.h b/qlist.h
new file mode 100644
index 0000000..b38786e
--- /dev/null
+++ b/qlist.h
@@ -0,0 +1,27 @@ 
+#ifndef QLIST
+#define QLIST
+
+#include "qobject.h"
+#include "qemu-queue.h"
+#include "qemu-common.h"
+
+typedef struct QListEntry {
+    QObject *value;
+    QTAILQ_ENTRY(QListEntry) next;
+} QListEntry;
+
+typedef struct QList {
+    QObject_HEAD;
+    QTAILQ_HEAD(,QListEntry) head;
+} QList;
+
+#define qlist_append(qlist, obj) \
+        qlist_append_obj(qlist, QOBJECT(obj))
+
+QList *qlist_new(void);
+void qlist_append_obj(QList *qlist, QObject *obj);
+void qlist_iter(const QList *qlist,
+                void (*iter)(QObject *obj, void *opaque), void *opaque);
+QList *qobject_to_qlist(const QObject *obj);
+
+#endif /* QLIST */
diff --git a/qobject.h b/qobject.h
index dcc8c63..4cc9287 100644
--- a/qobject.h
+++ b/qobject.h
@@ -40,6 +40,7 @@  typedef enum {
     QTYPE_QINT,
     QTYPE_QSTRING,
     QTYPE_QDICT,
+    QTYPE_QLIST,
 } qtype_code;
 
 struct QObject;