Commit 1912bcbc authored by Sebastian Dröge's avatar Sebastian Dröge 🍵 Committed by GStreamer Marge Bot
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devicemonitor: Only fail start() if no provider at all could be started

Also refactor various internals of the monitor code:
  - Don't allow starting twice but just return directly when starting a
    second time.
  - Don't end up in an inconsistent state if call start() a second time
    while the monitor is starting up.
  - Remove complicated cookie code: it was not possible to add/remove
    filters while the monitor was started anyway so this was only useful
    in the very small time-window while starting the monitor or while
    getting the devices. Instead disallow adding/removing filters while
    the monitor is starting, and when getting devices work on a snapshot
    of providers/filters.

Fixes #667

Part-of: <!1189>
parent 139bfc8a
Pipeline #432064 waiting for manual action with stages
in 38 minutes and 29 seconds
......@@ -108,10 +108,10 @@ struct _GstDeviceMonitorPrivate
GstBus *bus;
GPtrArray *providers;
guint cookie;
GPtrArray *filters;
GList *started_providers;
guint last_id;
GList *hidden;
gboolean show_all;
......@@ -129,6 +129,9 @@ G_DEFINE_TYPE_WITH_PRIVATE (GstDeviceMonitor, gst_device_monitor,
static void gst_device_monitor_dispose (GObject * object);
static guint gst_device_monitor_add_filter_unlocked (GstDeviceMonitor * monitor,
const gchar * classes, GstCaps * caps);
struct DeviceFilter
{
guint id;
......@@ -137,11 +140,24 @@ struct DeviceFilter
GstCaps *caps;
};
static struct DeviceFilter *
device_filter_copy (struct DeviceFilter *filter)
{
struct DeviceFilter *copy = g_slice_new0 (struct DeviceFilter);
copy->classesv = g_strdupv (filter->classesv);
copy->caps = filter->caps ? gst_caps_ref (filter->caps) : NULL;
return copy;
}
static void
device_filter_free (struct DeviceFilter *filter)
{
g_strfreev (filter->classesv);
gst_caps_unref (filter->caps);
if (filter->caps)
gst_caps_unref (filter->caps);
g_slice_free (struct DeviceFilter, filter);
}
......@@ -357,9 +373,11 @@ gst_device_monitor_dispose (GObject * object)
GList *
gst_device_monitor_get_devices (GstDeviceMonitor * monitor)
{
GList *devices = NULL, *hidden = NULL;
GQueue providers = G_QUEUE_INIT, filters = G_QUEUE_INIT;
GList *hidden = NULL;
GQueue devices = G_QUEUE_INIT;
GList *l;
guint i;
guint cookie;
g_return_val_if_fail (GST_IS_DEVICE_MONITOR (monitor), NULL);
......@@ -377,13 +395,6 @@ gst_device_monitor_get_devices (GstDeviceMonitor * monitor)
return NULL;
}
again:
g_list_free_full (devices, gst_object_unref);
g_list_free_full (hidden, g_free);
devices = NULL;
hidden = NULL;
for (i = 0; i < monitor->priv->providers->len; i++) {
GstDeviceProvider *provider =
g_ptr_array_index (monitor->priv->providers, i);
......@@ -391,37 +402,41 @@ again:
update_hidden_providers_list (&hidden, provider);
}
cookie = monitor->priv->cookie;
/* Create a copy of all current providers and filters while keeping the lock
* and afterwards unlock and work with this snapshot */
for (i = 0; i < monitor->priv->providers->len; i++) {
GList *tmpdev;
GstDeviceProvider *provider =
gst_object_ref (g_ptr_array_index (monitor->priv->providers, i));
GList *item;
g_ptr_array_index (monitor->priv->providers, i);
if (!is_provider_hidden (monitor, hidden, provider)) {
GST_OBJECT_UNLOCK (monitor);
g_queue_push_tail (&providers, gst_object_ref (provider));
}
}
for (i = 0; i < monitor->priv->filters->len; i++) {
struct DeviceFilter *filter = g_ptr_array_index (monitor->priv->filters, i);
tmpdev = gst_device_provider_get_devices (provider);
g_queue_push_tail (&filters, device_filter_copy (filter));
}
GST_OBJECT_UNLOCK (monitor);
GST_OBJECT_LOCK (monitor);
} else {
tmpdev = NULL;
}
for (l = providers.head; l; l = l->next) {
GstDeviceProvider *provider = l->data;
GList *tmpdev, *item, *filter_item;
tmpdev = gst_device_provider_get_devices (provider);
for (item = tmpdev; item; item = item->next) {
GstDevice *dev = GST_DEVICE (item->data);
GstCaps *caps = gst_device_get_caps (dev);
guint j;
for (j = 0; j < monitor->priv->filters->len; j++) {
struct DeviceFilter *filter =
g_ptr_array_index (monitor->priv->filters, j);
for (filter_item = filters.head; filter_item;
filter_item = filter_item->next) {
struct DeviceFilter *filter = filter_item->data;
if (gst_caps_can_intersect (filter->caps, caps) &&
gst_device_has_classesv (dev, filter->classesv)) {
devices = g_list_prepend (devices, gst_object_ref (dev));
g_queue_push_tail (&devices, gst_object_ref (dev));
break;
}
}
......@@ -429,16 +444,13 @@ again:
}
g_list_free_full (tmpdev, gst_object_unref);
gst_object_unref (provider);
if (monitor->priv->cookie != cookie)
goto again;
}
g_list_free_full (hidden, g_free);
GST_OBJECT_UNLOCK (monitor);
g_queue_clear_full (&providers, (GDestroyNotify) gst_object_unref);
g_queue_clear_full (&filters, (GDestroyNotify) device_filter_free);
return g_list_reverse (devices);
return devices.head;
}
/**
......@@ -449,7 +461,8 @@ again:
* %GST_MESSAGE_DEVICE_ADDED and %GST_MESSAGE_DEVICE_REMOVED messages
* will be emitted on the bus when the list of devices changes.
*
* Returns: %TRUE if the device monitoring could be started
* Returns: %TRUE if the device monitoring could be started, i.e. at least a
* single device provider was started successfully.
*
* Since: 1.4
*/
......@@ -457,19 +470,24 @@ again:
gboolean
gst_device_monitor_start (GstDeviceMonitor * monitor)
{
guint cookie, i;
GList *pending = NULL, *started = NULL, *removed = NULL;
guint i;
GQueue pending = G_QUEUE_INIT;
GList *started = NULL;
GstDeviceProvider *provider;
g_return_val_if_fail (GST_IS_DEVICE_MONITOR (monitor), FALSE);
GST_OBJECT_LOCK (monitor);
if (monitor->priv->filters->len == 0) {
if (monitor->priv->started) {
GST_OBJECT_UNLOCK (monitor);
GST_DEBUG_OBJECT (monitor, "Monitor started already");
return TRUE;
}
if (monitor->priv->filters->len == 0) {
GST_WARNING_OBJECT (monitor, "No filters have been set, will expose all "
"devices found");
gst_device_monitor_add_filter (monitor, NULL, NULL);
GST_OBJECT_LOCK (monitor);
gst_device_monitor_add_filter_unlocked (monitor, NULL, NULL);
}
if (monitor->priv->providers->len == 0) {
......@@ -478,74 +496,39 @@ gst_device_monitor_start (GstDeviceMonitor * monitor)
return FALSE;
}
gst_bus_set_flushing (monitor->priv->bus, FALSE);
again:
cookie = monitor->priv->cookie;
monitor->priv->started = TRUE;
g_list_free_full (pending, gst_object_unref);
pending = NULL;
removed = started;
started = NULL;
gst_bus_set_flushing (monitor->priv->bus, FALSE);
for (i = 0; i < monitor->priv->providers->len; i++) {
GstDeviceProvider *provider;
GList *find;
provider = g_ptr_array_index (monitor->priv->providers, i);
find = g_list_find (removed, provider);
if (find) {
/* this was already started, move to started list */
removed = g_list_remove_link (removed, find);
started = g_list_concat (started, find);
} else {
/* not started, add to pending list */
pending = g_list_append (pending, gst_object_ref (provider));
}
g_queue_push_tail (&pending, gst_object_ref (provider));
}
g_list_free_full (removed, gst_object_unref);
removed = NULL;
while (pending) {
GstDeviceProvider *provider = pending->data;
while ((provider = g_queue_pop_head (&pending))) {
GST_OBJECT_UNLOCK (monitor);
if (!gst_device_provider_start (provider))
goto start_failed;
if (gst_device_provider_start (provider)) {
started = g_list_prepend (started, provider);
} else {
gst_object_unref (provider);
}
GST_OBJECT_LOCK (monitor);
started = g_list_prepend (started, provider);
pending = g_list_delete_link (pending, pending);
if (monitor->priv->cookie != cookie)
goto again;
}
monitor->priv->started = TRUE;
GST_OBJECT_UNLOCK (monitor);
g_list_free_full (started, gst_object_unref);
return TRUE;
start_failed:
{
GST_OBJECT_LOCK (monitor);
if (started) {
monitor->priv->started_providers = started;
} else {
gst_bus_set_flushing (monitor->priv->bus, TRUE);
GST_OBJECT_UNLOCK (monitor);
while (started) {
GstDeviceProvider *provider = started->data;
monitor->priv->started = FALSE;
}
gst_device_provider_stop (provider);
gst_object_unref (provider);
GST_OBJECT_UNLOCK (monitor);
started = g_list_delete_link (started, started);
}
return FALSE;
}
return started != NULL;
}
/**
......@@ -559,7 +542,6 @@ start_failed:
void
gst_device_monitor_stop (GstDeviceMonitor * monitor)
{
guint i;
GList *started = NULL;
g_return_if_fail (GST_IS_DEVICE_MONITOR (monitor));
......@@ -567,13 +549,15 @@ gst_device_monitor_stop (GstDeviceMonitor * monitor)
gst_bus_set_flushing (monitor->priv->bus, TRUE);
GST_OBJECT_LOCK (monitor);
for (i = 0; i < monitor->priv->providers->len; i++) {
GstDeviceProvider *provider =
g_ptr_array_index (monitor->priv->providers, i);
if (gst_device_provider_is_started (provider))
started = g_list_prepend (started, gst_object_ref (provider));
if (!monitor->priv->started) {
GST_DEBUG_OBJECT (monitor, "Monitor was not started yet");
GST_OBJECT_UNLOCK (monitor);
return;
}
started = monitor->priv->started_providers;
monitor->priv->started_providers = NULL;
monitor->priv->started = FALSE;
GST_OBJECT_UNLOCK (monitor);
while (started) {
......@@ -584,11 +568,6 @@ gst_device_monitor_stop (GstDeviceMonitor * monitor)
started = g_list_delete_link (started, started);
gst_object_unref (provider);
}
GST_OBJECT_LOCK (monitor);
monitor->priv->started = FALSE;
GST_OBJECT_UNLOCK (monitor);
}
static void
......@@ -645,15 +624,26 @@ guint
gst_device_monitor_add_filter (GstDeviceMonitor * monitor,
const gchar * classes, GstCaps * caps)
{
GList *factories = NULL;
struct DeviceFilter *filter;
guint id = 0;
gboolean matched = FALSE;
guint id;
g_return_val_if_fail (GST_IS_DEVICE_MONITOR (monitor), 0);
g_return_val_if_fail (!monitor->priv->started, 0);
GST_OBJECT_LOCK (monitor);
id = gst_device_monitor_add_filter_unlocked (monitor, classes, caps);
GST_OBJECT_UNLOCK (monitor);
return id;
}
static guint
gst_device_monitor_add_filter_unlocked (GstDeviceMonitor * monitor,
const gchar * classes, GstCaps * caps)
{
GList *factories = NULL;
struct DeviceFilter *filter;
guint id = 0;
gboolean matched = FALSE;
filter = g_slice_new0 (struct DeviceFilter);
filter->id = monitor->priv->last_id++;
......@@ -702,7 +692,6 @@ gst_device_monitor_add_filter (GstDeviceMonitor * monitor,
G_CALLBACK (bus_sync_message), monitor);
gst_object_unref (bus);
g_ptr_array_add (monitor->priv->providers, provider);
monitor->priv->cookie++;
}
}
......@@ -717,8 +706,6 @@ gst_device_monitor_add_filter (GstDeviceMonitor * monitor,
id = filter->id;
g_ptr_array_add (monitor->priv->filters, filter);
GST_OBJECT_UNLOCK (monitor);
return id;
}
......@@ -775,7 +762,6 @@ gst_device_monitor_remove_filter (GstDeviceMonitor * monitor, guint filter_id)
}
if (!valid) {
monitor->priv->cookie++;
gst_device_monitor_remove (monitor, i);
i--;
}
......
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