GStreamer: improve tracing of GstMessages

warning/info/state_changed are often useful to see parsed properly.

* print them in a parsed manner on the QDebug output
* introduce a QCompactGstMessageAdaptor adaptor that can be used to
parse these messages in a consistent manner in message handlers. this
can be used to remove boilerplate code.

Pick-to: 6.5
Change-Id: I0ca76bcfc69628b747fd5e095cc1c783287acb3c
Reviewed-by: Jøger Hansegård <joger.hansegard@qt.io>
(cherry picked from commit 43bb01c87898a11942920cc58475c3543b8dbc2e)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

7 files changed, 147 insertions, 59 deletions

diff --git a/src/plugins/multimedia/gstreamer/audio/qgstreameraudiodecoder.cpp b/src/plugins/multimedia/gstreamer/audio/qgstreameraudiodecoder.cpp
index 5f51c92ca..310fdd994 100644
--- a/src/plugins/multimedia/gstreamer/audio/qgstreameraudiodecoder.cpp
+++ b/src/plugins/multimedia/gstreamer/audio/qgstreameraudiodecoder.cpp
@@ -134,8 +134,8 @@ bool QGstreamerAudioDecoder::processBusMessage(const QGstreamerMessage &message)
             gst_message_parse_state_changed(gm, &oldState, &newState, &pending);
 
             if constexpr (extendedMessageTracing)
-                qCDebug(qLcGstreamerAudioDecoder) << "    state changed message from" << oldState
-                                                  << "to" << newState << pending;
+                qCDebug(qLcGstreamerAudioDecoder)
+                        << "    state changed" << QCompactGstMessageAdaptor(message);
 
             bool isDecoding = false;
             switch (newState) {
@@ -177,33 +177,30 @@ bool QGstreamerAudioDecoder::processBusMessage(const QGstreamerMessage &message)
             else
                 processInvalidMedia(QAudioDecoder::ResourceError,
                                     QString::fromUtf8(err.get()->message));
-            qCWarning(qLcGstreamerAudioDecoder) << "Error:" << err;
+
+            qCWarning(qLcGstreamerAudioDecoder) << "Error:" << QCompactGstMessageAdaptor(message);
             break;
         }
-        case GST_MESSAGE_WARNING: {
-            QUniqueGErrorHandle err;
-            QGString debug;
-            gst_message_parse_warning(gm, &err, &debug);
-            qCWarning(qLcGstreamerAudioDecoder) << "Warning:" << err;
+
+        case GST_MESSAGE_WARNING:
+            qCWarning(qLcGstreamerAudioDecoder) << "Warning:" << QCompactGstMessageAdaptor(message);
             break;
-        }
-        case GST_MESSAGE_INFO: {
-            if (qLcGstreamerAudioDecoder().isDebugEnabled()) {
-                QUniqueGErrorHandle err;
-                QGString debug;
-                gst_message_parse_info(gm, &err, &debug);
-                qDebug() << "Info:" << err;
-            }
+
+        case GST_MESSAGE_INFO:
+            if (qLcGstreamerAudioDecoder().isDebugEnabled())
+                qDebug() << "Info:" << QCompactGstMessageAdaptor(message);
+
             break;
-        }
+
         default:
             break;
         }
     } else if (GST_MESSAGE_TYPE(gm) == GST_MESSAGE_ERROR) {
+        qCDebug(qLcGstreamerAudioDecoder) << "    error" << QCompactGstMessageAdaptor(message);
+
         QUniqueGErrorHandle err;
         QGString debug;
         gst_message_parse_error(gm, &err, &debug);
-        qCDebug(qLcGstreamerAudioDecoder) << "    error" << err << debug;
 
         QAudioDecoder::Error qerror = QAudioDecoder::ResourceError;
         if (err.get()->domain == GST_STREAM_ERROR) {
diff --git a/src/plugins/multimedia/gstreamer/audio/qgstreameraudiosink.cpp b/src/plugins/multimedia/gstreamer/audio/qgstreameraudiosink.cpp
index 5399a3e64..6fd972524 100644
--- a/src/plugins/multimedia/gstreamer/audio/qgstreameraudiosink.cpp
+++ b/src/plugins/multimedia/gstreamer/audio/qgstreameraudiosink.cpp
@@ -181,12 +181,7 @@ bool QGStreamerAudioSink::processBusMessage(const QGstreamerMessage &message)
         break;
     case GST_MESSAGE_ERROR: {
         setError(QAudio::IOError);
-        QUniqueGErrorHandle error;
-        QGString debug;
-
-        gst_message_parse_error(msg, &error, &debug);
-        qDebug() << "Error:" << error;
-
+        qDebug() << "Error:" << QCompactGstMessageAdaptor(message);
         break;
     }
     default:
diff --git a/src/plugins/multimedia/gstreamer/audio/qgstreameraudiosource.cpp b/src/plugins/multimedia/gstreamer/audio/qgstreameraudiosource.cpp
index ba9823d98..829d116a2 100644
--- a/src/plugins/multimedia/gstreamer/audio/qgstreameraudiosource.cpp
+++ b/src/plugins/multimedia/gstreamer/audio/qgstreameraudiosource.cpp
@@ -4,14 +4,16 @@
 #include <QtCore/qcoreapplication.h>
 #include <QtCore/qdebug.h>
 #include <QtCore/qmath.h>
-#include <private/qaudiohelpers_p.h>
+#include <QtMultimedia/private/qaudiohelpers_p.h>
 
 #include "qgstreameraudiosource_p.h"
 #include "qgstreameraudiodevice_p.h"
+#include "common/qgst_p.h"
+#include "common/qgst_debug_p.h"
+
 #include <sys/types.h>
 #include <unistd.h>
 
-#include <gst/gst.h>
 Q_DECLARE_OPAQUE_POINTER(GstSample *);
 Q_DECLARE_METATYPE(GstSample *);
 
@@ -204,12 +206,7 @@ gboolean QGStreamerAudioSource::busMessage(GstBus *, GstMessage *msg, gpointer u
         break;
     case GST_MESSAGE_ERROR: {
         input->setError(QAudio::IOError);
-        QUniqueGErrorHandle error;
-        QGString debug;
-
-        gst_message_parse_error (msg, &error, &debug);
-        qDebug() << "Error:" << error.get();
-
+        qDebug() << "Error:" << QCompactGstMessageAdaptor(msg);
         break;
     }
     default:
diff --git a/src/plugins/multimedia/gstreamer/common/qgst_debug.cpp b/src/plugins/multimedia/gstreamer/common/qgst_debug.cpp
index ee28a5c45..ea749c817 100644
--- a/src/plugins/multimedia/gstreamer/common/qgst_debug.cpp
+++ b/src/plugins/multimedia/gstreamer/common/qgst_debug.cpp
@@ -172,6 +172,42 @@ QDebug operator<<(QDebug dbg, const GstMessage *msg)
         break;
     }
 
+    case GST_MESSAGE_WARNING: {
+        QUniqueGErrorHandle err;
+        QGString debug;
+        gst_message_parse_warning(const_cast<GstMessage *>(msg), &err, &debug);
+
+        dbg << GST_MESSAGE_TYPE_NAME(msg) << ", Source: " << GST_MESSAGE_SRC_NAME(msg)
+            << ", Timestamp: " << GST_MESSAGE_TIMESTAMP(msg) << ", Warning: " << err << " ("
+            << debug << ")";
+        break;
+    }
+
+    case GST_MESSAGE_INFO: {
+        QUniqueGErrorHandle err;
+        QGString debug;
+        gst_message_parse_info(const_cast<GstMessage *>(msg), &err, &debug);
+
+        dbg << GST_MESSAGE_TYPE_NAME(msg) << ", Source: " << GST_MESSAGE_SRC_NAME(msg)
+            << ", Timestamp: " << GST_MESSAGE_TIMESTAMP(msg) << ", Info: " << err << " (" << debug
+            << ")";
+        break;
+    }
+
+    case GST_MESSAGE_STATE_CHANGED: {
+        GstState oldState;
+        GstState newState;
+        GstState pending;
+
+        gst_message_parse_state_changed(const_cast<GstMessage *>(msg), &oldState, &newState,
+                                        &pending);
+
+        dbg << GST_MESSAGE_TYPE_NAME(msg) << ", Source: " << GST_MESSAGE_SRC_NAME(msg)
+            << ", Timestamp: " << GST_MESSAGE_TIMESTAMP(msg) << ", OldState: " << oldState
+            << ", NewState: " << newState << "Pending State: " << pending;
+        break;
+    }
+
     default: {
         dbg << GST_MESSAGE_TYPE_NAME(msg) << ", Source: " << GST_MESSAGE_SRC_NAME(msg)
             << ", Timestamp: " << GST_MESSAGE_TIMESTAMP(msg);
@@ -316,4 +352,67 @@ QDebug operator<<(QDebug dbg, const GError *error)
     return dbg << error->message;
 }
 
+QCompactGstMessageAdaptor::QCompactGstMessageAdaptor(const QGstreamerMessage &m)
+    : QCompactGstMessageAdaptor{
+          m.message(),
+      }
+{
+}
+
+QCompactGstMessageAdaptor::QCompactGstMessageAdaptor(GstMessage *m)
+    : msg{
+          m,
+      }
+{
+}
+
+QDebug operator<<(QDebug dbg, const QCompactGstMessageAdaptor &m)
+{
+    std::optional<QDebugStateSaver> saver(dbg);
+    dbg.nospace();
+
+    switch (GST_MESSAGE_TYPE(m.msg)) {
+    case GST_MESSAGE_ERROR: {
+        QUniqueGErrorHandle err;
+        QGString debug;
+        gst_message_parse_error(m.msg, &err, &debug);
+        dbg << err << " (" << debug << ")";
+        return dbg;
+    }
+
+    case GST_MESSAGE_WARNING: {
+        QUniqueGErrorHandle err;
+        QGString debug;
+        gst_message_parse_warning(m.msg, &err, &debug);
+        dbg << err << " (" << debug << ")";
+        return dbg;
+    }
+
+    case GST_MESSAGE_INFO: {
+        QUniqueGErrorHandle err;
+        QGString debug;
+        gst_message_parse_info(m.msg, &err, &debug);
+
+        dbg << err << " (" << debug << ")";
+        return dbg;
+    }
+
+    case GST_MESSAGE_STATE_CHANGED: {
+        GstState oldState;
+        GstState newState;
+        GstState pending;
+
+        gst_message_parse_state_changed(m.msg, &oldState, &newState, &pending);
+
+        dbg << oldState << "->" << newState << "(pending: " << pending << ")";
+        return dbg;
+    }
+
+    default: {
+        saver.reset();
+        return dbg << m.msg;
+    }
+    }
+}
+
 QT_END_NAMESPACE
diff --git a/src/plugins/multimedia/gstreamer/common/qgst_debug_p.h b/src/plugins/multimedia/gstreamer/common/qgst_debug_p.h
index d64c240c6..31c722a90 100644
--- a/src/plugins/multimedia/gstreamer/common/qgst_debug_p.h
+++ b/src/plugins/multimedia/gstreamer/common/qgst_debug_p.h
@@ -54,6 +54,15 @@ QDebug operator<<(QDebug, GstPadDirection);
 QDebug operator<<(QDebug, const GValue *);
 QDebug operator<<(QDebug, const GError *);
 
+struct QCompactGstMessageAdaptor
+{
+    explicit QCompactGstMessageAdaptor(const QGstreamerMessage &m);
+    explicit QCompactGstMessageAdaptor(GstMessage *m);
+    GstMessage *msg;
+};
+
+QDebug operator<<(QDebug, const QCompactGstMessageAdaptor &);
+
 QT_END_NAMESPACE
 
 #endif
diff --git a/src/plugins/multimedia/gstreamer/common/qgstreamermediaplayer.cpp b/src/plugins/multimedia/gstreamer/common/qgstreamermediaplayer.cpp
index 3e3df7057..4dd5695dc 100644
--- a/src/plugins/multimedia/gstreamer/common/qgstreamermediaplayer.cpp
+++ b/src/plugins/multimedia/gstreamer/common/qgstreamermediaplayer.cpp
@@ -362,8 +362,8 @@ bool QGstreamerMediaPlayer::processBusMessage(const QGstreamerMessage &message)
         GstState    pending;
 
         gst_message_parse_state_changed(gm, &oldState, &newState, &pending);
-        qCDebug(qLcMediaPlayer) << "    state changed message from" << oldState << "to" << newState
-                                << pending;
+        qCDebug(qLcMediaPlayer) << "    state changed message from"
+                                << QCompactGstMessageAdaptor(message);
 
         switch (newState) {
         case GST_STATE_VOID_PENDING:
@@ -427,11 +427,11 @@ bool QGstreamerMediaPlayer::processBusMessage(const QGstreamerMessage &message)
         break;
     }
     case GST_MESSAGE_ERROR: {
+        qCDebug(qLcMediaPlayer) << "    error" << QCompactGstMessageAdaptor(message);
+
         QUniqueGErrorHandle err;
         QUniqueGStringHandle debug;
         gst_message_parse_error(gm, &err, &debug);
-        qCDebug(qLcMediaPlayer) << "    error" << err << debug;
-
         GQuark errorDomain = err.get()->domain;
         gint errorCode = err.get()->code;
 
@@ -458,23 +458,17 @@ bool QGstreamerMediaPlayer::processBusMessage(const QGstreamerMessage &message)
         mediaStatusChanged(QMediaPlayer::InvalidMedia);
         break;
     }
-    case GST_MESSAGE_WARNING: {
-        QUniqueGErrorHandle err;
-        QUniqueGStringHandle debug;
-        gst_message_parse_warning (gm, &err, &debug);
-        qCWarning(qLcMediaPlayer) << "Warning:" << err;
+
+    case GST_MESSAGE_WARNING:
+        qCWarning(qLcMediaPlayer) << "Warning:" << QCompactGstMessageAdaptor(message);
         playerPipeline.dumpGraph("warning");
         break;
-    }
-    case GST_MESSAGE_INFO: {
-        if (qLcMediaPlayer().isDebugEnabled()) {
-            QUniqueGErrorHandle err;
-            QUniqueGStringHandle debug;
-            gst_message_parse_info (gm, &err, &debug);
-            qCDebug(qLcMediaPlayer) << "Info:" << err;
-        }
+
+    case GST_MESSAGE_INFO:
+        if (qLcMediaPlayer().isDebugEnabled())
+            qCDebug(qLcMediaPlayer) << "Info:" << QCompactGstMessageAdaptor(message);
         break;
-    }
+
     case GST_MESSAGE_SEGMENT_START: {
         qCDebug(qLcMediaPlayer) << "    segment start message, updating position";
         QGstStructure structure(gst_message_get_structure(gm));
diff --git a/src/plugins/multimedia/gstreamer/mediacapture/qgstreamermediaencoder.cpp b/src/plugins/multimedia/gstreamer/mediacapture/qgstreamermediaencoder.cpp
index 083186985..9c335a185 100644
--- a/src/plugins/multimedia/gstreamer/mediacapture/qgstreamermediaencoder.cpp
+++ b/src/plugins/multimedia/gstreamer/mediacapture/qgstreamermediaencoder.cpp
@@ -84,10 +84,12 @@ bool QGstreamerMediaEncoder::processBusMessage(const QGstreamerMessage &msg)
     }
 
     case GST_MESSAGE_ERROR: {
+        qCDebug(qLcMediaEncoderGst)
+                << "received error:" << msg.source().name() << QCompactGstMessageAdaptor(msg);
+
         QUniqueGErrorHandle err;
         QGString debug;
         gst_message_parse_error(msg.message(), &err, &debug);
-        qCDebug(qLcMediaEncoderGst) << "received error:" << msg.source().name() << err << debug;
         error(QMediaRecorder::ResourceError, QString::fromUtf8(err.get()->message));
         if (!m_finalizing)
             stop();
@@ -96,14 +98,9 @@ bool QGstreamerMediaEncoder::processBusMessage(const QGstreamerMessage &msg)
     }
 
     case GST_MESSAGE_STATE_CHANGED: {
-        if constexpr (traceStateChange) {
-            GstState oldState;
-            GstState newState;
-            GstState pending;
-            gst_message_parse_state_changed(msg.message(), &oldState, &newState, &pending);
-            qCDebug(qLcMediaEncoderGst) << "received state change from" << msg.source().name()
-                                        << oldState << newState << pending;
-        }
+        if constexpr (traceStateChange)
+            qCDebug(qLcMediaEncoderGst)
+                    << "received state change" << QCompactGstMessageAdaptor(msg);
 
         return false;
     }