From 8c3e6eab95959571050570da44169113d34bd05f Mon Sep 17 00:00:00 2001
From: heckflosse <heckflosse67@gmx.de>
Date: Tue, 2 Feb 2016 15:31:30 +0100
Subject: [PATCH] Fix crash when opening a folder containing dng files with
 corrupted thumbs, fixes #3129

---
 rtengine/rawimage.cc    | 16 ++++++++++++++++
 rtengine/rawimage.h     |  2 ++
 rtengine/rtthumbnail.cc |  2 +-
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/rtengine/rawimage.cc b/rtengine/rawimage.cc
index 7eb057b67..3b491eab5 100644
--- a/rtengine/rawimage.cc
+++ b/rtengine/rawimage.cc
@@ -743,6 +743,22 @@ RawImage::is_supportedThumb() const
              !thumb_load_raw );
 }
 
+bool
+RawImage::is_jpegThumb() const
+{
+    return ( (thumb_width * thumb_height) > 0 &&
+              write_thumb == &rtengine::RawImage::jpeg_thumb &&
+             !thumb_load_raw );
+}
+
+bool
+RawImage::is_ppmThumb() const
+{
+    return ( (thumb_width * thumb_height) > 0 &&
+             write_thumb == &rtengine::RawImage::ppm_thumb &&
+             !thumb_load_raw );
+}
+
 void RawImage::getXtransMatrix( char XtransMatrix[6][6])
 {
     for(int row = 0; row < 6; row++)
diff --git a/rtengine/rawimage.h b/rtengine/rawimage.h
index fcc615997..de2baed32 100644
--- a/rtengine/rawimage.h
+++ b/rtengine/rawimage.h
@@ -275,6 +275,8 @@ public:
         return ifp;
     }
     bool is_supportedThumb() const ;
+    bool is_jpegThumb() const ;
+    bool is_ppmThumb() const ;
     int get_thumbOffset()
     {
         return int(thumb_offset);
diff --git a/rtengine/rtthumbnail.cc b/rtengine/rtthumbnail.cc
index 781b7e566..1f81012ad 100644
--- a/rtengine/rtthumbnail.cc
+++ b/rtengine/rtthumbnail.cc
@@ -182,7 +182,7 @@ Thumbnail* Thumbnail::loadQuickFromRaw (const Glib::ustring& fname, RawMetaDataL
 
         if ( (unsigned char)data[1] == 0xd8 ) {
             err = img->loadJPEGFromMemory(data, ri->get_thumbLength());
-        } else {
+        } else if (ri->is_ppmThumb()) {
             err = img->loadPPMFromMemory(data, ri->get_thumbWidth(), ri->get_thumbHeight(), ri->get_thumbSwap(), ri->get_thumbBPS());
         }
     }