[Qemu-devel] [PATCH 3/9] QSource: QEMU event source object

[Michael Roth <mdroth@linux.vnet.ibm.com>]

This references QContext, which will be introduced later (and also
references this). These will likely be squashed eventually, but we leave
them separate for now for easier review.

This implements a QOM-based event source object which is used in much
the same way as a GSource.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 include/qcontext/qsource.h |   63 +++++++++++++++++++
 qcontext/qsource.c         |  143 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 206 insertions(+)
 create mode 100644 include/qcontext/qsource.h
 create mode 100644 qcontext/qsource.c

diff --git a/include/qcontext/qsource.h b/include/qcontext/qsource.h
new file mode 100644
index 0000000..7c6dd75
--- /dev/null
+++ b/include/qcontext/qsource.h
@@ -0,0 +1,63 @@
+/*
+ * QSource: QEMU event source class
+ *
+ * Copyright IBM Corp. 2013
+ *
+ * Authors:
+ *  Michael Roth      <mdroth@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#ifndef QSOURCE_H
+#define QSOURCE_H
+
+#include "qom/object.h"
+#include "qcontext/qcontext.h"
+
+typedef struct QSource QSource;
+
+typedef bool (*QSourceCB)(QSource *qsource);
+
+typedef struct QSourceFuncs {
+    bool (*prepare)(QSource *qsource, int *timeout);
+    bool (*check)(QSource *qsource);
+    bool (*dispatch)(QSource *qsource);
+    void (*finalize)(QSource *qsource);
+} QSourceFuncs;
+
+typedef struct QSourceClass {
+    ObjectClass parent_class;
+
+    void (*add_poll)(QSource *qsource, GPollFD *pfd);
+    void (*remove_poll)(QSource *qsource, GPollFD *pfd);
+    void (*set_source_funcs)(QSource *qsource, QSourceFuncs funcs);
+    QSourceCB (*get_callback_func)(QSource *qsource);
+    void (*set_callback_func)(QSource *qsource, QSourceCB cb);
+    void (*set_user_data)(QSource *qsource, void *user_data);
+    void *(*get_user_data)(QSource *qsource);
+} QSourceClass;
+
+struct QSource {
+    /* <private */
+    Object parent_obj;
+
+    QSourceFuncs source_funcs;
+    QSourceCB callback_func;
+    GArray *poll_fds;
+    void *user_data;
+    struct QContext *ctx;
+    char *name;
+
+    /* <public> */
+};
+
+#define TYPE_QSOURCE "qsource"
+#define QSOURCE(obj) OBJECT_CHECK(QSource, (obj), TYPE_QSOURCE)
+#define QSOURCE_CLASS(klass) OBJECT_CLASS_CHECK(QSourceClass, (klass), TYPE_QSOURCE)
+#define QSOURCE_GET_CLASS(obj) OBJECT_GET_CLASS(QSourceClass, (obj), TYPE_QSOURCE)
+
+QSource *qsource_new(QSourceFuncs source_funcs, QSourceCB cb, const char *name,
+                   void *opaque);
+
+#endif /* QSOURCE_H */
diff --git a/qcontext/qsource.c b/qcontext/qsource.c
new file mode 100644
index 0000000..1f3dcb5
--- /dev/null
+++ b/qcontext/qsource.c
@@ -0,0 +1,143 @@
+/*
+ * QSource: QEMU event source class
+ *
+ * Copyright IBM Corp. 2013
+ *
+ * Authors:
+ *  Michael Roth      <mdroth@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#include <glib.h>
+#include "qom/object.h"
+#include "qcontext/qcontext.h"
+#include "qemu/module.h"
+
+/* FIXME: this basically causes us to destroy/rebuild an
+ * attached QSource/GSource every time we modify. What we
+ * should really have is an interface in the QContext for
+ * modifying an already attached source to avoid so much
+ * churn for simple action like adding poll fds to an
+ * source. The alternative is to require users to
+ * explicitly detach QSources before modifying them, but
+ * updating poll FDs/callbacks etc is a common operation
+ * for QSource/GSource callbacks so this limits functionality
+ * substantially
+ */
+static void qsource_update(QSource *qsource)
+{
+    QContext *ctx = qsource->ctx;
+
+    if (ctx) {
+        qcontext_detach(ctx, qsource, NULL);
+        qcontext_attach(ctx, qsource, NULL);
+    }
+}
+
+static void qsource_add_poll(QSource *qsource, GPollFD *pfd)
+{
+    g_array_append_val(qsource->poll_fds, pfd);
+    qsource_update(qsource);
+}
+
+static void qsource_remove_poll(QSource *qsource, GPollFD *pfd)
+{
+    bool done = false;
+
+    while (!done) {
+        done = true;
+        guint i;
+        for (i = 0; i < qsource->poll_fds->len; i++) {
+            if (g_array_index(qsource->poll_fds, GPollFD *, i) == pfd) {
+                g_array_remove_index(qsource->poll_fds, i);
+                /* iterate again to make sure we get them all */
+                done = false;
+                break;
+            }
+        }
+    }
+
+    qsource_update(qsource);
+}
+
+static void qsource_set_source_funcs(QSource *qsource, QSourceFuncs funcs)
+{
+    qsource->source_funcs = funcs;
+    qsource_update(qsource);
+}
+
+static QSourceCB qsource_get_callback_func(QSource *qsource)
+{
+    return qsource->callback_func;
+}
+
+static void qsource_set_callback_func(QSource *qsource, QSourceCB callback_func)
+{
+    qsource->callback_func = callback_func;
+    qsource_update(qsource);
+}
+
+static void qsource_set_user_data(QSource *qsource, void *user_data)
+{
+    qsource->user_data = user_data;
+    qsource_update(qsource);
+}
+
+static void *qsource_get_user_data(QSource *qsource)
+{
+    return qsource->user_data;
+}
+
+static void qsource_initfn(Object *obj)
+{
+    QSource *qsource = QSOURCE(obj);
+    qsource->poll_fds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
+    qsource->ctx = NULL;
+}
+
+static void qsource_class_initfn(ObjectClass *class, void *data)
+{
+    QSourceClass *k = QSOURCE_CLASS(class);
+
+    k->add_poll = qsource_add_poll;
+    k->remove_poll = qsource_remove_poll;
+    k->set_source_funcs = qsource_set_source_funcs;
+    k->get_callback_func = qsource_get_callback_func;
+    k->set_callback_func = qsource_set_callback_func;
+    k->get_user_data = qsource_get_user_data;
+    k->set_user_data = qsource_set_user_data;
+}
+
+TypeInfo qsource_info = {
+    .name = TYPE_QSOURCE,
+    .parent = TYPE_OBJECT,
+    .instance_size = sizeof(QSource),
+    .class_size = sizeof(QSourceClass),
+    .instance_init = qsource_initfn,
+    .class_init = qsource_class_initfn,
+    .interfaces = (InterfaceInfo[]) {
+        { },
+    },
+};
+
+static void qsource_register_types(void)
+{
+    type_register_static(&qsource_info);
+}
+
+type_init(qsource_register_types)
+
+QSource *qsource_new(QSourceFuncs funcs, QSourceCB cb, const char *name, void *opaque)
+{
+    QSource *qsource = QSOURCE(object_new(TYPE_QSOURCE));
+    QSourceClass *qsourcek = QSOURCE_GET_CLASS(qsource);
+
+    qsource->name = g_strdup(name);
+
+    qsourcek->set_source_funcs(qsource, funcs);
+    qsourcek->set_callback_func(qsource, cb);
+    qsourcek->set_user_data(qsource, opaque);
+
+    return qsource;
+}
-- 
1.7.9.5