Reimplement orphaned texture handling

The previous implementation was a bit error prone
(there was a reproducable "dead pointer" issue)
and had duplicated code (dma, egl and eglstream share the same code).

The new implementation fixes both issues (and more):

 - no more 'this' capture on a lambda where the 'this' isn't an object
   and hence can go out of scope without the lambda knowing.

 - no more duplicated code as we now have a singleton as our orphanage:
   QWaylandTextureOrphanage
   3 (dma, egl, eglstream) HW-integrations use this singleton

 - the class itself as well as it's container are thread-safe
   by the usage of QMutex/QMutexLocker.
   This also includes the deletion code within the orphanage.
   As the orphanes are 100% owned by the orphanage,
   they are protected from double deletion.

 - The cleanup due to QOpenGLContext::aboutToBeDestroyed is
   now ctx specific, no more lamdba-per-texture.

Change-Id: I36e82fae796864319bed7ebdb5154e93dbe96394
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
(cherry picked from commit 2cea2d8520af4f3647f2e7aa7444b68c9c1e51cf)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

8 files changed, 186 insertions, 225 deletions

diff --git a/src/compositor/CMakeLists.txt b/src/compositor/CMakeLists.txt
index 593d6194c..434411d0e 100644
--- a/src/compositor/CMakeLists.txt
+++ b/src/compositor/CMakeLists.txt
@@ -150,6 +150,7 @@ qt_internal_extend_target(WaylandCompositor CONDITION QT_FEATURE_opengl
         hardware_integration/qwlserverbufferintegration.cpp hardware_integration/qwlserverbufferintegration_p.h
         hardware_integration/qwlserverbufferintegrationfactory.cpp hardware_integration/qwlserverbufferintegrationfactory_p.h
         hardware_integration/qwlserverbufferintegrationplugin.cpp hardware_integration/qwlserverbufferintegrationplugin_p.h
+        hardware_integration/qwltextureorphanage.cpp hardware_integration/qwltextureorphanage_p.h
     PUBLIC_LIBRARIES
         Qt::OpenGL
 )
diff --git a/src/compositor/hardware_integration/qwltextureorphanage.cpp b/src/compositor/hardware_integration/qwltextureorphanage.cpp
new file mode 100644
index 000000000..c1337190a
--- /dev/null
+++ b/src/compositor/hardware_integration/qwltextureorphanage.cpp
@@ -0,0 +1,108 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
+
+#include "qwltextureorphanage_p.h"
+
+#include <QOpenGLContext>
+#include <QOpenGLTexture>
+#include <QDebug>
+#include <QtTypeTraits>
+#include <QMutexLocker>
+
+QT_BEGIN_NAMESPACE
+
+Q_LOGGING_CATEGORY(qLcWTO, "qt.waylandcompositor.orphanage")
+
+Q_GLOBAL_STATIC(QtWayland::QWaylandTextureOrphanage, inst)
+
+namespace QtWayland {
+
+QWaylandTextureOrphanage::~QWaylandTextureOrphanage()
+{
+    QMutexLocker locker(&m_containerLock);
+    if (!m_orphanedTextures.isEmpty()) {
+        qCWarning(qLcWTO) << Q_FUNC_INFO << "m_orphanedTextures container isn't empty! content:"
+                          << m_orphanedTextures;
+    }
+}
+
+QWaylandTextureOrphanage *QWaylandTextureOrphanage::instance()
+{
+    return inst;
+}
+
+void QWaylandTextureOrphanage::admitTexture(QOpenGLTexture *tex, QOpenGLContext *ctx)
+{
+    qCDebug(qLcWTO) << Q_FUNC_INFO << "got a texture (" << (void *)tex
+                    << ") ready to be deleted! It's ctx:" << ctx;
+
+    {
+        QMutexLocker locker(&m_containerLock);
+        m_orphanedTextures.insert(ctx, tex);
+    }
+
+    connect(ctx, &QOpenGLContext::aboutToBeDestroyed, this,
+            &QWaylandTextureOrphanage::onContextAboutToBeDestroyed,
+            Qt::ConnectionType(Qt::DirectConnection | Qt::UniqueConnection));
+}
+
+void QWaylandTextureOrphanage::deleteTextures()
+{
+    QOpenGLContext *cCtx = QOpenGLContext::currentContext();
+
+    if (cCtx == nullptr) {
+        qCWarning(qLcWTO) << Q_FUNC_INFO << "cannot delete textures without current OpenGL context";
+        return;
+    }
+
+    {
+        QMutexLocker locker(&m_containerLock);
+
+        for (QOpenGLContext *aCtx : m_orphanedTextures.keys()) {
+            if (QOpenGLContext::areSharing(cCtx, aCtx)) {
+
+                qCDebug(qLcWTO) << Q_FUNC_INFO << "currentContext (" << cCtx
+                                << ") and ctx of orphane(s) (" << aCtx
+                                << ") are shared! => deleteTexturesByContext";
+
+                deleteTexturesByContext(aCtx);
+            }
+        }
+    }
+}
+
+void QWaylandTextureOrphanage::onContextAboutToBeDestroyed()
+{
+    QOpenGLContext *ctx = qobject_cast<QOpenGLContext *>(sender());
+    Q_ASSERT(ctx != nullptr);
+
+    qCDebug(qLcWTO) << Q_FUNC_INFO << " ctx (" << ctx
+                    << ") fired aboutToBeDestroyed => deleteTexturesByContext(ctx)";
+
+    {
+        QMutexLocker locker(&m_containerLock);
+        deleteTexturesByContext(ctx);
+    }
+}
+
+void QWaylandTextureOrphanage::deleteTexturesByContext(QOpenGLContext *ctx)
+{
+    // NOTE: We are (by class-internal design) locked (m_containerLock)
+    // when we enter this function!
+    // So in a debug-build we will fail below:
+    Q_ASSERT(!m_containerLock.tryLock());
+
+    QList<QOpenGLTexture *> texturesToDelete = m_orphanedTextures.values(ctx);
+    m_orphanedTextures.remove(ctx);
+
+    for (QOpenGLTexture *tex : texturesToDelete) {
+        delete tex;
+        qCDebug(qLcWTO) << Q_FUNC_INFO << " texture (" << (void *)tex << ") got deleted";
+    }
+}
+
+} // namespace QtWayland
+
+QT_END_NAMESPACE
+
+#include "moc_qwltextureorphanage_p.cpp"
diff --git a/src/compositor/hardware_integration/qwltextureorphanage_p.h b/src/compositor/hardware_integration/qwltextureorphanage_p.h
new file mode 100644
index 000000000..d267043e4
--- /dev/null
+++ b/src/compositor/hardware_integration/qwltextureorphanage_p.h
@@ -0,0 +1,64 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
+
+#ifndef QWLTEXTUREORPHANAGE_P_H
+#define QWLTEXTUREORPHANAGE_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QObject>
+#include <QMutex>
+#include <QLoggingCategory>
+#include <QtWaylandCompositor/qtwaylandcompositorglobal.h>
+
+QT_BEGIN_NAMESPACE
+
+class QOpenGLContext;
+class QOpenGLTexture;
+
+Q_DECLARE_LOGGING_CATEGORY(qLcWTO)
+
+namespace QtWayland {
+
+class Q_WAYLANDCOMPOSITOR_EXPORT QWaylandTextureOrphanage : public QObject
+{
+    Q_OBJECT
+
+public:
+    QWaylandTextureOrphanage(){};
+    ~QWaylandTextureOrphanage();
+
+    static QWaylandTextureOrphanage *instance();
+
+    // texture that isn't needed anymore will be "take care of" (killed) appropriately
+    void admitTexture(QOpenGLTexture *tex, QOpenGLContext *ctx);
+
+    // uses QOpenGLContext::currentContext to call deleteTexturesByContext on all shared ctx
+    void deleteTextures();
+
+public slots:
+    // uses sender() to call deleteTexturesByContext
+    void onContextAboutToBeDestroyed();
+
+private:
+    void deleteTexturesByContext(QOpenGLContext *ctx);
+
+    // tracks all the orphanes that need to be deleted
+    QMultiHash<QOpenGLContext *, QOpenGLTexture *> m_orphanedTextures;
+
+    QMutex m_containerLock;
+};
+
+} // namespace QtWayland
+
+QT_END_NAMESPACE
+#endif
diff --git a/src/hardwareintegration/compositor/linux-dmabuf-unstable-v1/linuxdmabuf.cpp b/src/hardwareintegration/compositor/linux-dmabuf-unstable-v1/linuxdmabuf.cpp
index c09496985..a608b9c4d 100644
--- a/src/hardwareintegration/compositor/linux-dmabuf-unstable-v1/linuxdmabuf.cpp
+++ b/src/hardwareintegration/compositor/linux-dmabuf-unstable-v1/linuxdmabuf.cpp
@@ -5,6 +5,7 @@
 #include "linuxdmabufclientbufferintegration.h"
 
 #include <QtWaylandCompositor/QWaylandCompositor>
+#include <QtWaylandCompositor/private/qwltextureorphanage_p.h>
 
 #include <drm_fourcc.h>
 #include <drm_mode.h>
@@ -262,7 +263,8 @@ void LinuxDmabufWlBuffer::buffer_destroy(Resource *resource)
 
     for (uint32_t i = 0; i < m_planesNumber; ++i) {
         if (m_textures[i] != nullptr) {
-            m_clientBufferIntegration->deleteGLTextureWhenPossible(m_textures[i], m_texturesContext[i]);
+            QtWayland::QWaylandTextureOrphanage::instance()->admitTexture(m_textures[i],
+                                                                          m_texturesContext[i]);
             m_textures[i] = nullptr;
             m_texturesContext[i] = nullptr;
             QObject::disconnect(m_texturesAboutToBeDestroyedConnection[i]);
diff --git a/src/hardwareintegration/compositor/linux-dmabuf-unstable-v1/linuxdmabufclientbufferintegration.cpp b/src/hardwareintegration/compositor/linux-dmabuf-unstable-v1/linuxdmabufclientbufferintegration.cpp
index 960ec461f..205f25d1f 100644
--- a/src/hardwareintegration/compositor/linux-dmabuf-unstable-v1/linuxdmabufclientbufferintegration.cpp
+++ b/src/hardwareintegration/compositor/linux-dmabuf-unstable-v1/linuxdmabufclientbufferintegration.cpp
@@ -6,6 +6,7 @@
 
 #include <QtWaylandCompositor/QWaylandCompositor>
 #include <QtWaylandCompositor/private/qwayland-server-wayland.h>
+#include <QtWaylandCompositor/private/qwltextureorphanage_p.h>
 #include <qpa/qplatformnativeinterface.h>
 #include <QtOpenGL/QOpenGLTexture>
 #include <QtCore/QVarLengthArray>
@@ -350,69 +351,6 @@ QList<uint64_t> LinuxDmabufClientBufferIntegration::supportedDrmModifiers(uint32
     return QList<uint64_t>();
 }
 
-
-void LinuxDmabufClientBufferIntegration::deleteGLTextureWhenPossible(QOpenGLTexture *texture, QOpenGLContext *ctx) {
-    QMutexLocker locker(&m_orphanedTexturesLock);
-
-    Q_ASSERT(m_orphanedTextures.size() == m_orphanedTexturesAboutToBeDestroyedConnection.size());
-
-    m_orphanedTextures << texture;
-    m_orphanedTexturesAboutToBeDestroyedConnection << QObject::connect(ctx, &QOpenGLContext::aboutToBeDestroyed,
-                                                                       ctx, [this, texture]() {
-        this->deleteSpecificOrphanedTexture(texture);
-    }, Qt::DirectConnection);
-}
-
-
-void LinuxDmabufClientBufferIntegration::deleteOrphanedTextures()
-{
-    Q_ASSERT(QOpenGLContext::currentContext());
-
-    QMutexLocker locker(&m_orphanedTexturesLock);
-
-    if (!m_orphanedTextures.isEmpty())
-        qCDebug(qLcWaylandCompositorHardwareIntegration) << "About to delete some textures: "
-                                                           << m_orphanedTextures;
-
-    qDeleteAll(m_orphanedTextures);
-
-    for (QMetaObject::Connection con : m_orphanedTexturesAboutToBeDestroyedConnection)
-           QObject::disconnect(con);
-
-    m_orphanedTexturesAboutToBeDestroyedConnection.clear();
-    m_orphanedTextures.clear();
-}
-
-void LinuxDmabufClientBufferIntegration::deleteSpecificOrphanedTexture(QOpenGLTexture *texture)
-{
-    Q_ASSERT(m_orphanedTextures.size() == m_orphanedTexturesAboutToBeDestroyedConnection.size());
-
-    QMutexLocker locker(&m_orphanedTexturesLock);
-
-    // In this case, deleteOrphanedTextures was called while we entered (see lock!) this function!
-    if (m_orphanedTextures.length()==0) {
-        qCWarning(qLcWaylandCompositorHardwareIntegration)
-                << Q_FUNC_INFO
-                << "Looks like deleteOrphanedTextures() and this function where called simultaneously!"
-                << "This might cause issues!";
-        return;
-    }
-
-    int i = m_orphanedTextures.indexOf(texture);
-    Q_ASSERT(i!=-1);  // If it isn't empty (see above if), then it should be guaranteed to still contain this texture
-
-    m_orphanedTextures.removeAt(i);
-    QMetaObject::Connection con = m_orphanedTexturesAboutToBeDestroyedConnection.takeAt(i);
-
-    QObject::disconnect(con);
-    delete texture;
-
-    qCDebug(qLcWaylandCompositorHardwareIntegration)
-            << Q_FUNC_INFO
-            << "texture deleted due to QOpenGLContext::aboutToBeDestroyed!"
-            << "Pointer (now dead) was:" << (void*)texture;
-}
-
 void LinuxDmabufClientBufferIntegration::deleteImage(EGLImageKHR image)
 {
     egl_destroy_image(m_eglDisplay, image);
@@ -459,7 +397,7 @@ LinuxDmabufClientBuffer::LinuxDmabufClientBuffer(LinuxDmabufClientBufferIntegrat
 QOpenGLTexture *LinuxDmabufClientBuffer::toOpenGlTexture(int plane)
 {
     // At this point we should have a valid OpenGL context, so it's safe to destroy textures
-    m_integration->deleteOrphanedTextures();
+    QtWayland::QWaylandTextureOrphanage::instance()->deleteTextures();
 
     if (!m_buffer)
         return nullptr;
diff --git a/src/hardwareintegration/compositor/linux-dmabuf-unstable-v1/linuxdmabufclientbufferintegration.h b/src/hardwareintegration/compositor/linux-dmabuf-unstable-v1/linuxdmabufclientbufferintegration.h
index 3749d88ea..b72a24d5d 100644
--- a/src/hardwareintegration/compositor/linux-dmabuf-unstable-v1/linuxdmabufclientbufferintegration.h
+++ b/src/hardwareintegration/compositor/linux-dmabuf-unstable-v1/linuxdmabufclientbufferintegration.h
@@ -46,10 +46,7 @@ public:
     QtWayland::ClientBuffer *createBufferFor(wl_resource *resource) override;
     bool importBuffer(wl_resource *resource, LinuxDmabufWlBuffer *linuxDmabufBuffer);
     void removeBuffer(wl_resource *resource);
-    void deleteOrphanedTextures();
-    void deleteSpecificOrphanedTexture(QOpenGLTexture *texture);
     void deleteImage(EGLImageKHR image);
-    void deleteGLTextureWhenPossible(QOpenGLTexture *texture, QOpenGLContext* ctx);
     PFNGLEGLIMAGETARGETTEXTURE2DOESPROC gl_egl_image_target_texture_2d = nullptr;
 
 private:
@@ -71,10 +68,6 @@ private:
     ::wl_display *m_wlDisplay = nullptr;
     bool m_displayBound = false;
 
-    QMutex m_orphanedTexturesLock;
-    QList<QOpenGLTexture *> m_orphanedTextures;
-    QList<QMetaObject::Connection> m_orphanedTexturesAboutToBeDestroyedConnection;
-
     QHash<EGLint, YuvFormatConversion> m_yuvFormats;
     bool m_supportsDmabufModifiers = false;
     QHash<struct ::wl_resource *, LinuxDmabufWlBuffer *> m_importedBuffers;
diff --git a/src/hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp b/src/hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp
index b8a5b2466..38b0e0c4b 100644
--- a/src/hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp
+++ b/src/hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp
@@ -4,6 +4,7 @@
 #include "waylandeglclientbufferintegration_p.h"
 
 #include <QtWaylandCompositor/QWaylandCompositor>
+#include <QtWaylandCompositor/private/qwltextureorphanage_p.h>
 #include <qpa/qplatformnativeinterface.h>
 #include <QtOpenGL/QOpenGLTexture>
 #include <QtGui/QGuiApplication>
@@ -150,9 +151,6 @@ public:
     void setupBufferAndCleanup(BufferState *bs, QOpenGLTexture *texture, int plane);
     void handleEglstreamTexture(WaylandEglClientBuffer *buffer, wl_resource *bufferHandle);
     void registerBuffer(struct ::wl_resource *buffer, BufferState state);
-    void deleteGLTextureWhenPossible(QOpenGLTexture *texture, QOpenGLContext *ctx);
-    void deleteOrphanedTextures();
-    void deleteSpecificOrphanedTexture(QOpenGLTexture *texture);
 
     EGLDisplay egl_display = EGL_NO_DISPLAY;
     bool display_bound = false;
@@ -160,11 +158,6 @@ public:
     QOffscreenSurface *offscreenSurface = nullptr;
     QOpenGLContext *localContext = nullptr;
 
-    QMutex orphanedTexturesLock;
-    QList<QOpenGLTexture *> orphanedTextures;
-    QList<QMetaObject::Connection> orphanedTexturesAboutToBeDestroyedConnection;
-
-
     PFNEGLBINDWAYLANDDISPLAYWL egl_bind_wayland_display = nullptr;
     PFNEGLUNBINDWAYLANDDISPLAYWL egl_unbind_wayland_display = nullptr;
     PFNEGLQUERYWAYLANDBUFFERWL_compat egl_query_wayland_buffer = nullptr;
@@ -417,74 +410,6 @@ void WaylandEglClientBufferIntegrationPrivate::handleEglstreamTexture(WaylandEgl
         localContext->doneCurrent();
 }
 
-void WaylandEglClientBufferIntegrationPrivate::deleteGLTextureWhenPossible(QOpenGLTexture *texture, QOpenGLContext *ctx) {
-    QMutexLocker locker(&orphanedTexturesLock);
-
-    Q_ASSERT(ctx != nullptr);
-    Q_ASSERT(orphanedTextures.size() == orphanedTexturesAboutToBeDestroyedConnection.size());
-
-    qCDebug(qLcWaylandCompositorHardwareIntegration)
-            << Q_FUNC_INFO << " got texture and ctx to be deleted!"
-            << (void*)texture << "; " << (void*)ctx;
-
-    orphanedTextures << texture;
-    orphanedTexturesAboutToBeDestroyedConnection << QObject::connect(ctx, &QOpenGLContext::aboutToBeDestroyed,
-                                                                     ctx, [this, texture]() {
-        this->deleteSpecificOrphanedTexture(texture);
-    }, Qt::DirectConnection);
-}
-
-void WaylandEglClientBufferIntegrationPrivate::deleteOrphanedTextures()
-{
-    Q_ASSERT(QOpenGLContext::currentContext());
-
-    QMutexLocker locker(&orphanedTexturesLock);
-
-    for (int i=0; i < orphanedTextures.size(); i++) {
-        qCDebug(qLcWaylandCompositorHardwareIntegration)
-                << Q_FUNC_INFO << " about to delete a texture: "
-                << (void*)orphanedTextures[i];
-    }
-
-    qDeleteAll(orphanedTextures);
-
-    for (QMetaObject::Connection con : orphanedTexturesAboutToBeDestroyedConnection)
-        QObject::disconnect(con);
-
-    orphanedTexturesAboutToBeDestroyedConnection.clear();
-    orphanedTextures.clear();
-}
-
-void WaylandEglClientBufferIntegrationPrivate::deleteSpecificOrphanedTexture(QOpenGLTexture *texture)
-{
-    Q_ASSERT(orphanedTextures.size() == orphanedTexturesAboutToBeDestroyedConnection.size());
-
-    QMutexLocker locker(&orphanedTexturesLock);
-
-    // In this case, deleteOrphanedTextures was called while we entered (see lock!) this function!
-    if (orphanedTextures.length()==0) {
-        qCWarning(qLcWaylandCompositorHardwareIntegration)
-                << Q_FUNC_INFO
-                << "Looks like deleteOrphanedTextures() and this function where called simultaneously!"
-                << "This might cause issues!";
-        return;
-    }
-
-    int i = orphanedTextures.indexOf(texture);
-    Q_ASSERT(i!=-1);  // If it isn't empty (see above if), then it should be guaranteed to still contain this texture
-
-    orphanedTextures.removeAt(i);
-    QMetaObject::Connection con = orphanedTexturesAboutToBeDestroyedConnection.takeAt(i);
-
-    QObject::disconnect(con);
-    delete texture;
-
-    qCDebug(qLcWaylandCompositorHardwareIntegration)
-            << Q_FUNC_INFO
-            << "texture deleted due to QOpenGLContext::aboutToBeDestroyed!"
-            << "Pointer (now dead) was:" << (void*)texture;
-}
-
 WaylandEglClientBufferIntegration::WaylandEglClientBufferIntegration()
     : d_ptr(new WaylandEglClientBufferIntegrationPrivate)
 {
@@ -611,7 +536,8 @@ WaylandEglClientBuffer::~WaylandEglClientBuffer()
                         << (void*)d->textures[i] << "; " << (void*)d->texturesContext[i]
                         <<  " ... current context might be the same: " << QOpenGLContext::currentContext();
 
-                p->deleteGLTextureWhenPossible(d->textures[i], d->texturesContext[i]);
+                QtWayland::QWaylandTextureOrphanage::instance()->admitTexture(
+                        d->textures[i], d->texturesContext[i]);
                 d->textures[i] = nullptr;               // in case the aboutToBeDestroyed lambda is called while we where here
                 d->texturesContext[i] = nullptr;
                 QObject::disconnect(d->texturesAboutToBeDestroyedConnection[i]);
@@ -662,7 +588,7 @@ QOpenGLTexture *WaylandEglClientBuffer::toOpenGlTexture(int plane)
 {
     auto *p = WaylandEglClientBufferIntegrationPrivate::get(m_integration);
     // At this point we should have a valid OpenGL context, so it's safe to destroy textures
-    p->deleteOrphanedTextures();
+    QtWayland::QWaylandTextureOrphanage::instance()->deleteTextures();
 
     if (!m_buffer)
         return nullptr;
diff --git a/src/hardwareintegration/compositor/wayland-eglstream-controller/waylandeglstreamintegration.cpp b/src/hardwareintegration/compositor/wayland-eglstream-controller/waylandeglstreamintegration.cpp
index 23883a2a7..02d289ce0 100644
--- a/src/hardwareintegration/compositor/wayland-eglstream-controller/waylandeglstreamintegration.cpp
+++ b/src/hardwareintegration/compositor/wayland-eglstream-controller/waylandeglstreamintegration.cpp
@@ -16,6 +16,7 @@
 
 #include <QtWaylandCompositor/private/qwaylandcompositor_p.h>
 #include <QtWaylandCompositor/private/qwlbuffermanager_p.h>
+#include <QtWaylandCompositor/private/qwltextureorphanage_p.h>
 
 #include <EGL/egl.h>
 #include <EGL/eglext.h>
@@ -130,9 +131,6 @@ public:
     bool initEglStream(WaylandEglStreamClientBuffer *buffer, struct ::wl_resource *bufferHandle);
     void setupBufferAndCleanup(BufferState *bs, QOpenGLTexture *texture, int plane);
     void handleEglstreamTexture(WaylandEglStreamClientBuffer *buffer);
-    void deleteGLTextureWhenPossible(QOpenGLTexture *texture, QOpenGLContext *ctx);
-    void deleteOrphanedTextures();
-    void deleteSpecificOrphanedTexture(QOpenGLTexture *texture);
 
     EGLDisplay egl_display = EGL_NO_DISPLAY;
     bool display_bound = false;
@@ -140,10 +138,6 @@ public:
     QOffscreenSurface *offscreenSurface = nullptr;
     QOpenGLContext *localContext = nullptr;
 
-    QMutex orphanedTexturesLock;
-    QList<QOpenGLTexture *> orphanedTextures;
-    QList<QMetaObject::Connection> orphanedTexturesAboutToBeDestroyedConnection;
-
     WaylandEglStreamController *eglStreamController = nullptr;
 
     PFNEGLBINDWAYLANDDISPLAYWL egl_bind_wayland_display = nullptr;
@@ -160,71 +154,6 @@ public:
 
 bool WaylandEglStreamClientBufferIntegrationPrivate::shuttingDown = false;
 
-
-void WaylandEglStreamClientBufferIntegrationPrivate::deleteGLTextureWhenPossible(QOpenGLTexture *texture, QOpenGLContext *ctx) {
-
-    QMutexLocker locker(&orphanedTexturesLock);
-
-    Q_ASSERT(orphanedTextures.size() == orphanedTexturesAboutToBeDestroyedConnection.size());
-
-    orphanedTextures << texture;
-    orphanedTexturesAboutToBeDestroyedConnection << QObject::connect(ctx, &QOpenGLContext::aboutToBeDestroyed,
-                                                                     ctx, [this, texture]() {
-        this->deleteSpecificOrphanedTexture(texture);
-    }, Qt::DirectConnection);
-}
-
-void WaylandEglStreamClientBufferIntegrationPrivate::deleteOrphanedTextures()
-{
-    Q_ASSERT(QOpenGLContext::currentContext());
-
-    QMutexLocker locker(&orphanedTexturesLock);
-
-    for (int i=0; i < orphanedTextures.size(); i++) {
-        qCDebug(qLcWaylandCompositorHardwareIntegration)
-                << Q_FUNC_INFO << " about to delete a texture: "
-                << (void*)orphanedTextures[i];
-    }
-
-    qDeleteAll(orphanedTextures);
-
-    for (QMetaObject::Connection con : orphanedTexturesAboutToBeDestroyedConnection)
-        QObject::disconnect(con);
-
-    orphanedTexturesAboutToBeDestroyedConnection.clear();
-    orphanedTextures.clear();
-}
-
-void WaylandEglStreamClientBufferIntegrationPrivate::deleteSpecificOrphanedTexture(QOpenGLTexture *texture)
-{
-    Q_ASSERT(orphanedTextures.size() == orphanedTexturesAboutToBeDestroyedConnection.size());
-
-    QMutexLocker locker(&orphanedTexturesLock);
-
-    // In this case, deleteOrphanedTextures was called while we entered (see lock!) this function!
-    if (orphanedTextures.length()==0) {
-        qCWarning(qLcWaylandCompositorHardwareIntegration)
-                << Q_FUNC_INFO
-                << "Looks like deleteOrphanedTextures() and this function where called simultaneously!"
-                << "This might cause issues!";
-        return;
-    }
-
-    int i = orphanedTextures.indexOf(texture);
-    Q_ASSERT(i!=-1);  // If it isn't empty (see above if), then it should be guaranteed to still contain this texture
-
-    orphanedTextures.removeAt(i);
-    QMetaObject::Connection con = orphanedTexturesAboutToBeDestroyedConnection.takeAt(i);
-
-    QObject::disconnect(con);
-    delete texture;
-
-    qCDebug(qLcWaylandCompositorHardwareIntegration)
-            << Q_FUNC_INFO
-            << "texture deleted due to QOpenGLContext::aboutToBeDestroyed!"
-            << "Pointer (now dead) was:" << (void*)texture;
-}
-
 bool WaylandEglStreamClientBufferIntegrationPrivate::ensureContext()
 {
     bool localContextNeeded = false;
@@ -481,7 +410,8 @@ WaylandEglStreamClientBuffer::~WaylandEglStreamClientBuffer()
                         << (void*)d->textures[i] << "; " << (void*)d->texturesContext[i]
                         <<  " ... current context might be the same: " << QOpenGLContext::currentContext();
 
-                p->deleteGLTextureWhenPossible(d->textures[i], d->texturesContext[i]);
+                QtWayland::QWaylandTextureOrphanage::instance()->admitTexture(
+                        d->textures[i], d->texturesContext[i]);
                 d->textures[i] = nullptr;               // in case the aboutToBeDestroyed lambda is called while we where here
                 d->texturesContext[i] = nullptr;
                 QObject::disconnect(d->texturesAboutToBeDestroyedConnection[i]);
@@ -512,9 +442,8 @@ QWaylandSurface::Origin WaylandEglStreamClientBuffer::origin() const
 
 QOpenGLTexture *WaylandEglStreamClientBuffer::toOpenGlTexture(int plane)
 {
-    auto *p = WaylandEglStreamClientBufferIntegrationPrivate::get(m_integration);
     // At this point we should have a valid OpenGL context, so it's safe to destroy textures
-    p->deleteOrphanedTextures();
+    QtWayland::QWaylandTextureOrphanage::instance()->deleteTextures();
 
     if (!m_buffer)
         return nullptr;