gstreamer/ext/qt/qtitem.cc
Bastien Reboulet 27ecd2c30d qmlglsink: fix crash when created/destroyed in quick succession
The crash is caused by a race condition where the render thread
calls a method on the QtGLVideoItem instance that was
previously destroyed by the main thread.
Also, less frequently, QtGLVideoItem::onSceneGraphInitialized
is called when QQuickItem::window is null, also causing a crash.

Fixes #798

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/merge_requests/777>
2020-10-20 18:12:20 +00:00

563 lines
13 KiB
C++

/*
* GStreamer
* Copyright (C) 2015 Matthew Waters <matthew@centricular.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdio.h>
#include <gst/video/video.h>
#include "qtitem.h"
#include "gstqsgtexture.h"
#include "gstqtglutility.h"
#include <QtCore/QRunnable>
#include <QtCore/QMutexLocker>
#include <QtCore/QPointer>
#include <QtGui/QGuiApplication>
#include <QtQuick/QQuickWindow>
#include <QtQuick/QSGSimpleTextureNode>
/**
* SECTION:gtkgstglwidget
* @short_description: a #GtkGLArea that renders GStreamer video #GstBuffers
* @see_also: #GtkGLArea, #GstBuffer
*
* #QtGLVideoItem is an #QQuickItem that renders GStreamer video buffers.
*/
#define GST_CAT_DEFAULT qt_item_debug
GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
#define DEFAULT_FORCE_ASPECT_RATIO TRUE
#define DEFAULT_PAR_N 0
#define DEFAULT_PAR_D 1
enum
{
PROP_0,
PROP_FORCE_ASPECT_RATIO,
PROP_PIXEL_ASPECT_RATIO,
};
struct _QtGLVideoItemPrivate
{
GMutex lock;
/* properties */
gboolean force_aspect_ratio;
gint par_n, par_d;
gint display_width;
gint display_height;
gboolean negotiated;
GstBuffer *buffer;
GstCaps *caps;
GstVideoInfo v_info;
gboolean initted;
GstGLDisplay *display;
QOpenGLContext *qt_context;
GstGLContext *other_context;
GstGLContext *context;
};
class InitializeSceneGraph : public QRunnable
{
public:
InitializeSceneGraph(QtGLVideoItem *item);
void run();
private:
QPointer<QtGLVideoItem> item_;
};
InitializeSceneGraph::InitializeSceneGraph(QtGLVideoItem *item) :
item_(item)
{
}
void InitializeSceneGraph::run()
{
if(item_)
item_->onSceneGraphInitialized();
}
QtGLVideoItem::QtGLVideoItem()
{
static volatile gsize _debug;
if (g_once_init_enter (&_debug)) {
GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "qtglwidget", 0, "Qt GL Widget");
g_once_init_leave (&_debug, 1);
}
this->m_openGlContextInitialized = false;
this->setFlag (QQuickItem::ItemHasContents, true);
this->priv = g_new0 (QtGLVideoItemPrivate, 1);
this->priv->force_aspect_ratio = DEFAULT_FORCE_ASPECT_RATIO;
this->priv->par_n = DEFAULT_PAR_N;
this->priv->par_d = DEFAULT_PAR_D;
g_mutex_init (&this->priv->lock);
this->priv->display = gst_qt_get_gl_display();
connect(this, SIGNAL(windowChanged(QQuickWindow*)), this,
SLOT(handleWindowChanged(QQuickWindow*)));
this->proxy = QSharedPointer<QtGLVideoItemInterface>(new QtGLVideoItemInterface(this));
GST_DEBUG ("%p init Qt Video Item", this);
}
QtGLVideoItem::~QtGLVideoItem()
{
/* Before destroying the priv info, make sure
* no qmlglsink's will call in again, and that
* any ongoing calls are done by invalidating the proxy
* pointer */
GST_INFO ("%p Destroying QtGLVideoItem and invalidating the proxy %p", this, proxy.data());
proxy->invalidateRef();
proxy.clear();
g_mutex_clear (&this->priv->lock);
if (this->priv->context)
gst_object_unref(this->priv->context);
if (this->priv->other_context)
gst_object_unref(this->priv->other_context);
if (this->priv->display)
gst_object_unref(this->priv->display);
gst_buffer_replace (&this->priv->buffer, NULL);
gst_caps_replace (&this->priv->caps, NULL);
g_free (this->priv);
this->priv = NULL;
}
void
QtGLVideoItem::setDAR(gint num, gint den)
{
this->priv->par_n = num;
this->priv->par_d = den;
}
void
QtGLVideoItem::getDAR(gint * num, gint * den)
{
if (num)
*num = this->priv->par_n;
if (den)
*den = this->priv->par_d;
}
void
QtGLVideoItem::setForceAspectRatio(bool force_aspect_ratio)
{
this->priv->force_aspect_ratio = !!force_aspect_ratio;
}
bool
QtGLVideoItem::getForceAspectRatio()
{
return this->priv->force_aspect_ratio;
}
bool
QtGLVideoItem::itemInitialized()
{
return m_openGlContextInitialized;
}
QSGNode *
QtGLVideoItem::updatePaintNode(QSGNode * oldNode,
UpdatePaintNodeData * updatePaintNodeData)
{
if (!m_openGlContextInitialized) {
return oldNode;
}
QSGSimpleTextureNode *texNode = static_cast<QSGSimpleTextureNode *> (oldNode);
GstVideoRectangle src, dst, result;
GstQSGTexture *tex;
g_mutex_lock (&this->priv->lock);
if (gst_gl_context_get_current() == NULL)
gst_gl_context_activate (this->priv->other_context, TRUE);
GST_TRACE ("%p updatePaintNode", this);
if (!this->priv->caps) {
g_mutex_unlock (&this->priv->lock);
return NULL;
}
if (!texNode) {
texNode = new QSGSimpleTextureNode ();
texNode->setOwnsTexture (true);
texNode->setTexture (new GstQSGTexture ());
}
tex = static_cast<GstQSGTexture *> (texNode->texture());
tex->setCaps (this->priv->caps);
tex->setBuffer (this->priv->buffer);
texNode->markDirty(QSGNode::DirtyMaterial);
if (this->priv->force_aspect_ratio) {
src.w = this->priv->display_width;
src.h = this->priv->display_height;
dst.x = boundingRect().x();
dst.y = boundingRect().y();
dst.w = boundingRect().width();
dst.h = boundingRect().height();
gst_video_sink_center_rect (src, dst, &result, TRUE);
} else {
result.x = boundingRect().x();
result.y = boundingRect().y();
result.w = boundingRect().width();
result.h = boundingRect().height();
}
texNode->setRect (QRectF (result.x, result.y, result.w, result.h));
g_mutex_unlock (&this->priv->lock);
return texNode;
}
static void
_reset (QtGLVideoItem * qt_item)
{
gst_buffer_replace (&qt_item->priv->buffer, NULL);
gst_caps_replace (&qt_item->priv->caps, NULL);
qt_item->priv->negotiated = FALSE;
qt_item->priv->initted = FALSE;
}
void
QtGLVideoItemInterface::setBuffer (GstBuffer * buffer)
{
QMutexLocker locker(&lock);
if (qt_item == NULL) {
GST_WARNING ("%p actual item is NULL. setBuffer call ignored", this);
return;
}
if (!qt_item->priv->negotiated) {
GST_WARNING ("%p Got buffer on unnegotiated QtGLVideoItem. Dropping", this);
return;
}
g_mutex_lock (&qt_item->priv->lock);
gst_buffer_replace (&qt_item->priv->buffer, buffer);
QMetaObject::invokeMethod(qt_item, "update", Qt::QueuedConnection);
g_mutex_unlock (&qt_item->priv->lock);
}
void
QtGLVideoItem::onSceneGraphInitialized ()
{
if (this->window() == NULL)
return;
GST_DEBUG ("%p scene graph initialization with Qt GL context %p", this,
this->window()->openglContext ());
if (this->priv->qt_context == this->window()->openglContext ())
return;
this->priv->qt_context = this->window()->openglContext ();
if (this->priv->qt_context == NULL) {
g_assert_not_reached ();
return;
}
m_openGlContextInitialized = gst_qt_get_gl_wrapcontext (this->priv->display,
&this->priv->other_context, &this->priv->context);
GST_DEBUG ("%p created wrapped GL context %" GST_PTR_FORMAT, this,
this->priv->other_context);
emit itemInitializedChanged();
}
void
QtGLVideoItem::onSceneGraphInvalidated ()
{
GST_FIXME ("%p scene graph invalidated", this);
}
/**
* Retrieve and populate the GL context information from the current
* OpenGL context.
*/
gboolean
QtGLVideoItemInterface::initWinSys ()
{
QMutexLocker locker(&lock);
GError *error = NULL;
if (qt_item == NULL)
return FALSE;
g_mutex_lock (&qt_item->priv->lock);
if (qt_item->priv->display && qt_item->priv->qt_context
&& qt_item->priv->other_context && qt_item->priv->context) {
/* already have the necessary state */
g_mutex_unlock (&qt_item->priv->lock);
return TRUE;
}
if (!GST_IS_GL_DISPLAY (qt_item->priv->display)) {
GST_ERROR ("%p failed to retrieve display connection %" GST_PTR_FORMAT,
qt_item, qt_item->priv->display);
g_mutex_unlock (&qt_item->priv->lock);
return FALSE;
}
if (!GST_IS_GL_CONTEXT (qt_item->priv->other_context)) {
GST_ERROR ("%p failed to retrieve wrapped context %" GST_PTR_FORMAT, qt_item,
qt_item->priv->other_context);
g_mutex_unlock (&qt_item->priv->lock);
return FALSE;
}
qt_item->priv->context = gst_gl_context_new (qt_item->priv->display);
if (!qt_item->priv->context) {
g_mutex_unlock (&qt_item->priv->lock);
return FALSE;
}
if (!gst_gl_context_create (qt_item->priv->context, qt_item->priv->other_context,
&error)) {
GST_ERROR ("%s", error->message);
g_mutex_unlock (&qt_item->priv->lock);
return FALSE;
}
g_mutex_unlock (&qt_item->priv->lock);
return TRUE;
}
void
QtGLVideoItem::handleWindowChanged(QQuickWindow *win)
{
if (win) {
if (win->isSceneGraphInitialized())
win->scheduleRenderJob(new InitializeSceneGraph(this), QQuickWindow::BeforeSynchronizingStage);
else
connect(win, SIGNAL(sceneGraphInitialized()), this, SLOT(onSceneGraphInitialized()), Qt::DirectConnection);
connect(win, SIGNAL(sceneGraphInvalidated()), this, SLOT(onSceneGraphInvalidated()), Qt::DirectConnection);
} else {
this->priv->qt_context = NULL;
}
}
static gboolean
_calculate_par (QtGLVideoItem * widget, GstVideoInfo * info)
{
gboolean ok;
gint width, height;
gint par_n, par_d;
gint display_par_n, display_par_d;
guint display_ratio_num, display_ratio_den;
width = GST_VIDEO_INFO_WIDTH (info);
height = GST_VIDEO_INFO_HEIGHT (info);
par_n = GST_VIDEO_INFO_PAR_N (info);
par_d = GST_VIDEO_INFO_PAR_D (info);
if (!par_n)
par_n = 1;
/* get display's PAR */
if (widget->priv->par_n != 0 && widget->priv->par_d != 0) {
display_par_n = widget->priv->par_n;
display_par_d = widget->priv->par_d;
} else {
display_par_n = 1;
display_par_d = 1;
}
ok = gst_video_calculate_display_ratio (&display_ratio_num,
&display_ratio_den, width, height, par_n, par_d, display_par_n,
display_par_d);
if (!ok)
return FALSE;
GST_LOG ("%p PAR: %u/%u DAR:%u/%u", widget, par_n, par_d, display_par_n,
display_par_d);
if (height % display_ratio_den == 0) {
GST_DEBUG ("%p keeping video height", widget);
widget->priv->display_width = (guint)
gst_util_uint64_scale_int (height, display_ratio_num,
display_ratio_den);
widget->priv->display_height = height;
} else if (width % display_ratio_num == 0) {
GST_DEBUG ("%p keeping video width", widget);
widget->priv->display_width = width;
widget->priv->display_height = (guint)
gst_util_uint64_scale_int (width, display_ratio_den, display_ratio_num);
} else {
GST_DEBUG ("%p approximating while keeping video height", widget);
widget->priv->display_width = (guint)
gst_util_uint64_scale_int (height, display_ratio_num,
display_ratio_den);
widget->priv->display_height = height;
}
GST_DEBUG ("%p scaling to %dx%d", widget, widget->priv->display_width,
widget->priv->display_height);
return TRUE;
}
gboolean
QtGLVideoItemInterface::setCaps (GstCaps * caps)
{
QMutexLocker locker(&lock);
GstVideoInfo v_info;
g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
g_return_val_if_fail (gst_caps_is_fixed (caps), FALSE);
if (qt_item == NULL)
return FALSE;
if (qt_item->priv->caps && gst_caps_is_equal_fixed (qt_item->priv->caps, caps))
return TRUE;
if (!gst_video_info_from_caps (&v_info, caps))
return FALSE;
g_mutex_lock (&qt_item->priv->lock);
_reset (qt_item);
gst_caps_replace (&qt_item->priv->caps, caps);
if (!_calculate_par (qt_item, &v_info)) {
g_mutex_unlock (&qt_item->priv->lock);
return FALSE;
}
qt_item->priv->v_info = v_info;
qt_item->priv->negotiated = TRUE;
g_mutex_unlock (&qt_item->priv->lock);
return TRUE;
}
GstGLContext *
QtGLVideoItemInterface::getQtContext ()
{
QMutexLocker locker(&lock);
if (!qt_item || !qt_item->priv->other_context)
return NULL;
return (GstGLContext *) gst_object_ref (qt_item->priv->other_context);
}
GstGLContext *
QtGLVideoItemInterface::getContext ()
{
QMutexLocker locker(&lock);
if (!qt_item || !qt_item->priv->context)
return NULL;
return (GstGLContext *) gst_object_ref (qt_item->priv->context);
}
GstGLDisplay *
QtGLVideoItemInterface::getDisplay()
{
QMutexLocker locker(&lock);
if (!qt_item || !qt_item->priv->display)
return NULL;
return (GstGLDisplay *) gst_object_ref (qt_item->priv->display);
}
void
QtGLVideoItemInterface::setDAR(gint num, gint den)
{
QMutexLocker locker(&lock);
if (!qt_item)
return;
qt_item->setDAR(num, den);
}
void
QtGLVideoItemInterface::getDAR(gint * num, gint * den)
{
QMutexLocker locker(&lock);
if (!qt_item)
return;
qt_item->getDAR (num, den);
}
void
QtGLVideoItemInterface::setForceAspectRatio(bool force_aspect_ratio)
{
QMutexLocker locker(&lock);
if (!qt_item)
return;
qt_item->setForceAspectRatio(force_aspect_ratio);
}
bool
QtGLVideoItemInterface::getForceAspectRatio()
{
QMutexLocker locker(&lock);
if (!qt_item)
return FALSE;
return qt_item->getForceAspectRatio();
}
void
QtGLVideoItemInterface::invalidateRef()
{
QMutexLocker locker(&lock);
qt_item = NULL;
}