Implemented a safer and correct way of calling Gst.init()

Core/src/org/sleuthkit/autopsy/contentviewers/MediaPlayerPanel.java

@@ -74,6 +74,8 @@ import org.freedesktop.gstreamer.Format;
 import org.freedesktop.gstreamer.GstException;
 import org.freedesktop.gstreamer.event.SeekFlags;
 import org.freedesktop.gstreamer.event.SeekType;
+import org.sleuthkit.autopsy.contentviewers.utils.GstLoader;
+import org.sleuthkit.autopsy.contentviewers.utils.GstLoader.GstStatus;
 
 /**
  * This is a video player that is part of the Media View layered pane. It uses
@@ -540,23 +542,12 @@ public class MediaPlayerPanel extends JPanel implements MediaFileViewer.MediaVie
                 if (this.isCancelled()) {
                     return;
                 }
-
+                
-                // Setting the following property causes the GST
+                GstStatus loadStatus = GstLoader.tryLoad();
-                // Java bindings to call dispose() on the GST 
+                if(loadStatus == GstStatus.FAILURE) {
-                // service thread instead of running it in the GST
-                // Native Object Reaper thread.
-                System.setProperty("glib.reapOnEDT", "true");
-
-                // Initialize Gstreamer. It is safe to call this for every file.
-                // It was moved here from the constructor because having it happen
-                // earlier resulted in crashes on Linux. See JIRA-5888.
-                Gst.init();
-
-                if (!Gst.isInitialized()) {
-                    logger.log(Level.INFO, "GStreamer is not initialized."); //NON-NLS
                     return;
                 }
-
+                
                 Gst.getExecutor().submit(() -> {
                     //Video is ready for playback. Create new components
                     gstPlayBin = new PlayBin("VideoPlayer", tempFile.toURI());

Core/src/org/sleuthkit/autopsy/contentviewers/utils/GstLoader.java

@@ -0,0 +1,72 @@
+/*
+ * Autopsy Forensic Browser
+ *
+ * Copyright 2020 Basis Technology Corp.
+ * Contact: carrier <at> sleuthkit <dot> org
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.sleuthkit.autopsy.contentviewers.utils;
+
+import java.util.logging.Level;
+import org.freedesktop.gstreamer.Gst;
+import org.sleuthkit.autopsy.coreutils.Logger;
+import org.sleuthkit.autopsy.coreutils.MessageNotifyUtil;
+
+/**
+ *
+ * @author dsmyda
+ */
+public class GstLoader {
+
+    private static final Logger logger = Logger.getLogger(GstLoader.class.getName());
+    private static GstStatus status;
+
+    /**
+     * Attempts to load the gstreamer bindings. Only one attempt will be
+     * performed per Autopsy process. Clients should not attempt to interact
+     * with the gstreamer bindings unless the load was successful.
+     *
+     * @return Status - SUCCESS or FAILURE
+     */
+    public synchronized static GstStatus tryLoad() {
+        // Null is our 'unknown' status. Prior to the first call, the status
+        // is unknown.
+        if (status != null) {
+            return status;
+        }
+
+        try {
+            // Setting the following property causes the GST
+            // Java bindings to call dispose() on the GST 
+            // service thread instead of running it in the GST
+            // Native Object Reaper thread.
+            System.setProperty("glib.reapOnEDT", "true");
+            Gst.init();
+            status = GstStatus.SUCCESS;
+        } catch (Throwable ex) {
+            status = GstStatus.FAILURE;
+            MessageNotifyUtil.Message.error("A problem was encountered with"
+                    + "the video playback service. Video playback will"
+                    + " be disabled for the remainder of the session.");
+            logger.log(Level.WARNING, "Failed to load gsteamer bindings", ex);
+        }
+
+        return status;
+    }
+
+    public enum GstStatus {
+        SUCCESS, FAILURE
+    }
+}