From 984abc89a82e19fb5f22eebd0196bae57df4f7ca Mon Sep 17 00:00:00 2001
From: Jonas Kvinge <jonas@jkvinge.net>
Date: Mon, 22 Apr 2019 00:42:03 +0200
Subject: [PATCH] Fix chromaprinter unref buffer crash

---
 src/musicbrainz/chromaprinter.cpp | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/musicbrainz/chromaprinter.cpp b/src/musicbrainz/chromaprinter.cpp
index fd29ebd3e..e09748c85 100644
--- a/src/musicbrainz/chromaprinter.cpp
+++ b/src/musicbrainz/chromaprinter.cpp
@@ -133,7 +133,6 @@ QString Chromaprinter::CreateFingerprint() {
 
   // Wait until EOS or error
   GstMessage *msg = gst_bus_timed_pop_filtered(bus, kTimeoutSecs * GST_SECOND, static_cast<GstMessageType>(GST_MESSAGE_EOS | GST_MESSAGE_ERROR));
-
   if (msg != nullptr) {
     if (msg->type == GST_MESSAGE_ERROR) {
       // Report error
@@ -220,12 +219,16 @@ GstFlowReturn Chromaprinter::NewBufferCallback(GstAppSink *app_sink, gpointer se
   Chromaprinter *me = reinterpret_cast<Chromaprinter*>(self);
 
   GstSample *sample = gst_app_sink_pull_sample(app_sink);
+  if (!sample) return GST_FLOW_ERROR;
   GstBuffer *buffer = gst_sample_get_buffer(sample);
-  GstMapInfo map;
-  gst_buffer_map(buffer, &map, GST_MAP_READ);
-  me->buffer_.write(reinterpret_cast<const char*>(map.data), map.size);
-  gst_buffer_unmap(buffer, &map);
-  gst_buffer_unref(buffer);
+  if (buffer) {
+    GstMapInfo map;
+    if (gst_buffer_map(buffer, &map, GST_MAP_READ)) {
+      me->buffer_.write(reinterpret_cast<const char*>(map.data), map.size);
+      gst_buffer_unmap(buffer, &map);
+    }
+  }
+  gst_sample_unref(sample);
 
   return GST_FLOW_OK;