qemu/qobject/qlist.c
Eric Blake 55e1819c50 qobject: Simplify QObject
The QObject hierarchy is small enough, and unlikely to grow further
(since we only use it to map to JSON and already cover all JSON
types), that we can simplify things by not tracking a separate
vtable, but just inline the code element of the vtable QType
directly into QObject (renamed to type), and track a separate array
of destroy functions.  We can drop qnull_destroy_obj() in the
process.

The remaining QObject subclasses must export their destructor.

This also has the nice benefit of moving the typename 'QType'
out of the way, so that the next patch can repurpose it for a
nicer name for 'qtype_code'.

The various objects are still the same size (so no change in cache
line pressure), but now have less indirection (although I didn't
bother benchmarking to see if there is a noticeable speedup, as
we don't have hard evidence that this was in a performance hotspot
in the first place).

A future patch could drop the refcnt size to 32 bits for a smaller
struct on 64-bit architectures, if desired (we have limits on the
largest JSON that we are willing to parse, and will probably never
need to take full advantage of a 64-bit refcnt).

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1449033659-25497-2-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-12-17 08:21:28 +01:00

163 lines
3.1 KiB
C

/*
* QList Module
*
* Copyright (C) 2009 Red Hat Inc.
*
* Authors:
* Luiz Capitulino <lcapitulino@redhat.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/qmp/qlist.h"
#include "qapi/qmp/qobject.h"
#include "qemu/queue.h"
#include "qemu-common.h"
/**
* qlist_new(): Create a new QList
*
* Return strong reference.
*/
QList *qlist_new(void)
{
QList *qlist;
qlist = g_malloc(sizeof(*qlist));
qobject_init(QOBJECT(qlist), QTYPE_QLIST);
QTAILQ_INIT(&qlist->head);
return qlist;
}
static void qlist_copy_elem(QObject *obj, void *opaque)
{
QList *dst = opaque;
qobject_incref(obj);
qlist_append_obj(dst, obj);
}
QList *qlist_copy(QList *src)
{
QList *dst = qlist_new();
qlist_iter(src, qlist_copy_elem, dst);
return dst;
}
/**
* 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 = g_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 *qlist_pop(QList *qlist)
{
QListEntry *entry;
QObject *ret;
if (qlist == NULL || QTAILQ_EMPTY(&qlist->head)) {
return NULL;
}
entry = QTAILQ_FIRST(&qlist->head);
QTAILQ_REMOVE(&qlist->head, entry, next);
ret = entry->value;
g_free(entry);
return ret;
}
QObject *qlist_peek(QList *qlist)
{
QListEntry *entry;
QObject *ret;
if (qlist == NULL || QTAILQ_EMPTY(&qlist->head)) {
return NULL;
}
entry = QTAILQ_FIRST(&qlist->head);
ret = entry->value;
return ret;
}
int qlist_empty(const QList *qlist)
{
return QTAILQ_EMPTY(&qlist->head);
}
static void qlist_size_iter(QObject *obj, void *opaque)
{
size_t *count = opaque;
(*count)++;
}
size_t qlist_size(const QList *qlist)
{
size_t count = 0;
qlist_iter(qlist, qlist_size_iter, &count);
return count;
}
/**
* qobject_to_qlist(): Convert a QObject into a QList
*/
QList *qobject_to_qlist(const QObject *obj)
{
if (!obj || qobject_type(obj) != QTYPE_QLIST) {
return NULL;
}
return container_of(obj, QList, base);
}
/**
* qlist_destroy_obj(): Free all the memory allocated by a QList
*/
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);
g_free(entry);
}
g_free(qlist);
}