From b64401cbdd8d09ce06cad69d1d4586364ccc1090 Mon Sep 17 00:00:00 2001
From: Mark Pizzolato <mark@infocomm.com>
Date: Tue, 1 Dec 2015 08:04:01 -0800
Subject: [PATCH] VIDEO: Fix crash using libSDL on hosts which display using
 X11.

---
 sim_video.c | 75 ++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 54 insertions(+), 21 deletions(-)

diff --git a/sim_video.c b/sim_video.c
index 2339acd9..ed6c5fd4 100644
--- a/sim_video.c
+++ b/sim_video.c
@@ -284,6 +284,37 @@ int32 vid_width;
 int32 vid_height;
 t_bool vid_ready;
 #if SDL_MAJOR_VERSION == 1
+
+/*
+   Some platforms that use X11 display technology have libSDL 
+   environments which need to call XInitThreads when libSDL is used
+   in multi-threaded programs.  This routine attempts to locate
+   the X11 shareable library and if it is found loads it and calls
+   the XInitThreads routine to meet this requirement.
+ */
+#ifdef HAVE_DLOPEN
+#include <dlfcn.h>
+#endif
+
+static void _XInitThreads (void)
+{
+#ifdef HAVE_DLOPEN
+static void *hLib = 0;                      /* handle to Library */
+#define __STR_QUOTE(tok) #tok
+#define __STR(tok) __STR_QUOTE(tok)
+static const char* lib_name = "libX11." __STR(HAVE_DLOPEN);
+typedef int (*_func)();
+_func _func_ptr;
+
+if (!hLib)
+    hLib = dlopen(lib_name, RTLD_NOW);
+if (hLib)
+    _func_ptr = (_func)((size_t)dlsym(hLib, "XInitThreads"));
+if (_func_ptr)
+    _func_ptr();
+#endif
+}
+
 t_bool vid_key_state[SDLK_LAST];
 SDL_Surface *vid_image;                                 /* video buffer */
 SDL_Surface *vid_window;                                /* window handle */
@@ -322,7 +353,8 @@ user_event.type = SDL_USEREVENT;
 user_event.user.code = EVENT_EXIT;
 user_event.user.data1 = NULL;
 user_event.user.data2 = NULL;
-SDL_PushEvent (&user_event);
+while (SDL_PushEvent (&user_event) < 0)
+    sim_os_ms_sleep (10);
 return stat;
 }
 
@@ -335,6 +367,7 @@ main_argc = argc;
 main_argv = argv;
 
 #if SDL_MAJOR_VERSION == 1
+_XInitThreads();
 SDL_Init (SDL_INIT_VIDEO|SDL_INIT_NOPARACHUTE);
 
 vid_main_thread_handle = SDL_CreateThread (main_thread , NULL);
@@ -373,7 +406,7 @@ while (1) {
         }
     else {
         if (status < 0)
-            sim_printf ("main() - SDL_WaitEvent error: %s\n", SDL_GetError());
+            sim_printf ("main() - ` error: %s\n", SDL_GetError());
         }
     }
 SDL_WaitThread (vid_main_thread_handle, &status);
@@ -474,7 +507,8 @@ if (vid_active) {
         user_event.user.data1 = NULL;
         user_event.user.data2 = NULL;
 
-        SDL_PushEvent (&user_event);
+        while (SDL_PushEvent (&user_event) < 0)
+            sim_os_ms_sleep (10);
         if (vid_thread_handle) {
             SDL_WaitThread (vid_thread_handle, &status);
             vid_thread_handle = NULL;
@@ -545,17 +579,6 @@ return stat;
 
 void vid_draw (int32 x, int32 y, int32 w, int32 h, uint32 *buf)
 {
-#if SDL_MAJOR_VERSION == 1
-int32 i;
-uint32* pixels;
-
-sim_debug (SIM_VID_DBG_VIDEO, vid_dev, "vid_draw(%d, %d, %d, %d)\n", x, y, w, h);
-
-pixels = (uint32 *)vid_image->pixels;
-
-for (i = 0; i < h; i++)
-    memcpy (pixels + ((i + y) * vid_width) + x, buf + w*i, w*sizeof(*pixels));
-#else
 SDL_Event user_event;
 SDL_Rect *vid_dst;
 uint32 *vid_data;
@@ -578,7 +601,6 @@ if (SDL_PushEvent (&user_event) < 0) {
     free (vid_dst);
     free (vid_data);
     }
-#endif
 }
 
 t_stat vid_set_cursor (t_bool visible, uint32 width, uint32 height, uint8 *data, uint8 *mask)
@@ -1312,7 +1334,6 @@ SDL_WarpMouseInWindow (NULL, vid_cursor_x, vid_cursor_y);
 SDL_PumpEvents ();
 }
 
-#if SDL_MAJOR_VERSION != 1
 void vid_draw_region (SDL_UserEvent *event)
 {
 SDL_Rect *vid_dst = (SDL_Rect *)event->data1;
@@ -1320,14 +1341,25 @@ uint32 *buf = (uint32 *)event->data2;
 
 sim_debug (SIM_VID_DBG_VIDEO, vid_dev, "Draw Region Event: (%d,%d,%d,%d)\n", vid_dst->x, vid_dst->x, vid_dst->w, vid_dst->h);
 
+#if SDL_MAJOR_VERSION == 1
+if (1) {
+    int32 i;
+    uint32* pixels;
+
+    pixels = (uint32 *)vid_image->pixels;
+
+    for (i = 0; i < vid_dst->h; i++)
+        memcpy (pixels + ((i + vid_dst->y) * vid_width) + vid_dst->x, buf + vid_dst->w*i, vid_dst->w*sizeof(*pixels));
+    }
+#else
 if (SDL_UpdateTexture(vid_texture, vid_dst, buf, vid_dst->w*sizeof(*buf)))
     sim_printf ("%s: vid_draw() - SDL_UpdateTexture error: %s\n", sim_dname(vid_dev), SDL_GetError());
+#endif
 
 free (vid_dst);
 free (buf);
 event->data1 = NULL;
 }
-#endif
 
 int vid_video_events (void)
 {
@@ -1634,12 +1666,10 @@ if (0)                        while (SDL_PeepEvents (&event, 1, SDL_GETEVENT, SD
                     if (event.user.code == EVENT_CLOSE) {
                         event.user.code = 0;    /* Mark as done */
                         }
-#if SDL_MAJOR_VERSION != 1
                     if (event.user.code == EVENT_DRAW) {
                         vid_draw_region ((SDL_UserEvent*)&event);
                         event.user.code = 0;    /* Mark as done */
                         }
-#endif
                     if (event.user.code == EVENT_SHOW) {
                         vid_show_video_event ();
                         event.user.code = 0;    /* Mark as done */
@@ -1684,6 +1714,7 @@ return 0;
 int vid_thread (void *arg)
 {
 #if SDL_MAJOR_VERSION == 1
+_XInitThreads();
 SDL_Init (SDL_INIT_VIDEO|SDL_INIT_NOPARACHUTE);
 #else
 SDL_SetHint (SDL_HINT_RENDER_DRIVER, "software");
@@ -1998,7 +2029,8 @@ user_event.user.code = EVENT_SHOW;
 user_event.user.data1 = NULL;
 user_event.user.data2 = NULL;
 #if defined (SDL_MAIN_AVAILABLE)
-SDL_PushEvent (&user_event);
+while (SDL_PushEvent (&user_event) < 0)
+    sim_os_ms_sleep (10);
 #else
 vid_show_video_event ();
 #endif
@@ -2073,7 +2105,8 @@ user_event.user.code = EVENT_SCREENSHOT;
 user_event.user.data1 = NULL;
 user_event.user.data2 = NULL;
 #if defined (SDL_MAIN_AVAILABLE)
-SDL_PushEvent (&user_event);
+while (SDL_PushEvent (&user_event) < 0)
+    sim_os_ms_sleep (10);
 #else
 vid_screenshot_event ();
 #endif