[gthumb] jpeg loader: fixed abort in case of error

[Paolo Bacchilega <paobac src gnome org>]

commit 125987507cb2faf0cab658d0773b8dba7ed2fe6c
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sun Aug 19 20:47:44 2018 +0200

    jpeg loader: fixed abort in case of error
    
    do not call siglongjmp more then once in case of error

 extensions/cairo_io/cairo-image-surface-jpeg.c | 29 +++++++++++---------------
 1 file changed, 12 insertions(+), 17 deletions(-)
---
diff --git a/extensions/cairo_io/cairo-image-surface-jpeg.c b/extensions/cairo_io/cairo-image-surface-jpeg.c
index 73cb0e26..bc700c14 100644
--- a/extensions/cairo_io/cairo-image-surface-jpeg.c
+++ b/extensions/cairo_io/cairo-image-surface-jpeg.c
@@ -48,34 +48,28 @@ static void
 fatal_error_handler (j_common_ptr cinfo)
 {
        struct error_handler_data *errmgr;
-        char buffer[JMSG_LENGTH_MAX];
 
        errmgr = (struct error_handler_data *) cinfo->err;
+       if ((errmgr->error != NULL) && (*errmgr->error == NULL)) {
+               char buffer[JMSG_LENGTH_MAX];
 
-        /* Create the message */
-        (* cinfo->err->format_message) (cinfo, buffer);
+               /* Create the message */
+               (* cinfo->err->format_message) (cinfo, buffer);
 
-        /* broken check for *error == NULL for robustness against
-         * crappy JPEG library
-         */
-        if (errmgr->error && *errmgr->error == NULL) {
-                g_set_error (errmgr->error,
-                             GDK_PIXBUF_ERROR,
-                             GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+               g_set_error (errmgr->error,
+                            GDK_PIXBUF_ERROR,
+                            GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
                             _("Error interpreting JPEG image file: %s"),
-                             buffer);
-        }
-
-       siglongjmp (errmgr->setjmp_buffer, 1);
-
-        g_assert_not_reached ();
+                            buffer);
+               siglongjmp (errmgr->setjmp_buffer, 1);
+       }
 }
 
 
 static void
 output_message_handler (j_common_ptr cinfo)
 {
-       /* This method keeps libjpeg from dumping crap to stderr */
+       /* This method keeps libjpeg from dumping text to stderr */
        /* do nothing */
 }
 
@@ -588,6 +582,7 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
                        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CANCELLED, "");
 
                cairo_surface_destroy (surface);
+               surface = NULL;
        }
 
        if (read_all_scanlines)