From 71d15443fc2e012b14cb4c9e3b647738956ed2e2 Mon Sep 17 00:00:00 2001
From: nathan <nathan@dorkbox.com>
Date: Thu, 29 Oct 2015 02:21:24 +0100
Subject: [PATCH] Changed init order, and how the main loop gets started

---
 .../dorkbox/util/jna/linux/GtkSupport.java    | 78 +++++++++++--------
 1 file changed, 45 insertions(+), 33 deletions(-)

diff --git a/Dorkbox-Util/src/dorkbox/util/jna/linux/GtkSupport.java b/Dorkbox-Util/src/dorkbox/util/jna/linux/GtkSupport.java
index 655e27c..c703395 100644
--- a/Dorkbox-Util/src/dorkbox/util/jna/linux/GtkSupport.java
+++ b/Dorkbox-Util/src/dorkbox/util/jna/linux/GtkSupport.java
@@ -20,10 +20,13 @@ import java.util.concurrent.CountDownLatch;
 public
 class GtkSupport {
     public static final boolean isSupported;
-    private static boolean hasSwt = false;
+    private static final boolean hasSwt;
+
+    private static volatile boolean started = false;
 
     static {
         boolean hasSupport = false;
+        boolean hasSWT_ = false;
         try {
             if (Gtk.INSTANCE != null && Gobject.INSTANCE != null && GThread.INSTANCE != null) {
                 hasSupport = true;
@@ -31,61 +34,70 @@ class GtkSupport {
                 try {
                     Class<?> swtClass = Class.forName("org.eclipse.swt.widgets.Display");
                     if (swtClass != null) {
-                        hasSwt = true;
+                        hasSWT_ = true;
                     }
                 } catch (Throwable ignore) {
                 }
 
-                // If we are using GTK, we need to make sure the event loop is running. There can be multiple/nested loops.
+
+                // prep for the event loop.
                 // since SWT uses one already, it's not necessary to have two.
-                if (!hasSwt) {
+                if (!hasSWT_) {
                     Gtk instance = Gtk.INSTANCE;
                     instance.gtk_init(0, null);
                     GThread.INSTANCE.g_thread_init(null);
                     instance.gdk_threads_init();
-
-                    final CountDownLatch blockUntilStarted = new CountDownLatch(1);
-
-                    Thread gtkUpdateThread = new Thread() {
-                        @Override
-                        public
-                        void run() {
-                            Gtk instance = Gtk.INSTANCE;
-
-                            // notify our main thread to continue
-                            blockUntilStarted.countDown();
-                            instance.gdk_threads_enter();
-                            instance.gtk_main();
-                            // MUST leave as well!
-                            instance.gdk_threads_leave();
-                        }
-                    };
-                    gtkUpdateThread.setName("GTK Event Loop");
-                    gtkUpdateThread.start();
-
-                    try {
-                        // we CANNOT continue until the GTK thread has started! (ignored if SWT is used)
-                        blockUntilStarted.await();
-                    } catch (InterruptedException e) {
-                        e.printStackTrace();
-                    }
                 }
             }
         } catch (Throwable ignored) {
         }
 
         isSupported = hasSupport;
+        hasSwt = hasSWT_;
     }
 
     public static
-    void init() {
-        // placeholder to init GTK
+    void startGui() {
+        // only permit one startup per JVM instance
+        if (!started) {
+            started = true;
+
+            // startup the GTK GUI event loop. There can be multiple/nested loops.
+            // since SWT uses one already, it's not necessary to have two.
+            if (!hasSwt) {
+                final CountDownLatch blockUntilStarted = new CountDownLatch(1);
+                Thread gtkUpdateThread = new Thread() {
+                    @Override
+                    public
+                    void run() {
+                        Gtk instance = Gtk.INSTANCE;
+
+                        // notify our main thread to continue
+                        blockUntilStarted.countDown();
+                        instance.gdk_threads_enter();
+                        instance.gtk_main();
+                        // MUST leave as well!
+                        instance.gdk_threads_leave();
+                    }
+                };
+                gtkUpdateThread.setName("GTK Event Loop");
+                gtkUpdateThread.start();
+
+                try {
+                    // we CANNOT continue until the GTK thread has started! (ignored if SWT is used)
+                    blockUntilStarted.await();
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+            }
+        }
     }
 
     public static
-    void shutdownGTK() {
+    void shutdownGui() {
         if (isSupported && !hasSwt) {
             Gtk.INSTANCE.gtk_main_quit();
+            started = false;
         }
     }
 }