Added stat check to try to skip sparse files.

Sparse files, especially sparse video files, cause high cpu and memory
load when trying to get a thumbnail image out of them, using gst or ffmpeg
plugins.

For non sparse files, usually ((double)S_BLKSIZE * sb.st_blocks / sb.st_size) = 1.0,
but this is not always true, for example on file systems that support
compression, the ratio can be lower (ex. on ZFS), but not by too much for
already compressed video and image files.

We assume video files with ratio lower than 0.8 to be sparse and we avoid
them. Video files with ratio higher than 0.8 usually have enough valid
video frames, so getting a thumbnail out of them always succeeds. This
commit should fix bug #12259.

1 files changed, 31 insertions, 1 deletions

diff --git a/tumblerd/tumbler-registry.c b/tumblerd/tumbler-registry.c
index 77bc74f..c1337af 100644
--- a/tumblerd/tumbler-registry.c
+++ b/tumblerd/tumbler-registry.c
@@ -1,6 +1,7 @@
 /* vi:set et ai sw=2 sts=2 ts=2: */
 /*-
  * Copyright (c) 2009-2011 Jannis Pohlmann <jannis@xfce.org>
+ * Copyright (c) 2018      Ali Abdallah    <ali@xfce.org>
  *
  * This program is free software; you can redistribute it and/or 
  * modify it under the terms of the GNU General Public License as
@@ -25,13 +26,16 @@
 #include <glib.h>
 #include <glib-object.h>
 
+#include <sys/stat.h>
+
 #include <tumbler/tumbler.h>
 
 #include <tumblerd/tumbler-registry.h>
 #include <tumblerd/tumbler-specialized-thumbnailer.h>
 #include <tumblerd/tumbler-utils.h>
 
-
+/* Float block size used in the stat struct */
+#define TUMBLER_STAT_BLKSIZE 512.
 
 static void                tumbler_registry_finalize                  (GObject            *object);
 static void                tumbler_registry_remove_thumbnailer        (const gchar        *key,
@@ -461,11 +465,37 @@ tumbler_registry_get_thumbnailer_array (TumblerRegistry    *registry,
   /* iterate over all URIs */
   for (n = 0; n < length; ++n)
     {
+      gchar *filename;
+      struct stat sb;
+
       g_assert (TUMBLER_IS_FILE_INFO (infos[n]));
 
       /* reset */
       file_size = 0;
 
+      filename = g_filename_from_uri (tumbler_file_info_get_uri (infos[n]), NULL, NULL);
+
+      if (G_LIKELY(filename))
+      {
+        stat (filename, &sb);
+
+        g_free (filename);
+
+        if (!S_ISREG (sb.st_mode))
+          continue;
+
+        if (((TUMBLER_STAT_BLKSIZE * sb.st_blocks) / sb.st_size) < 0.8)
+        {
+          g_debug ("'%s' is probably a sparse file, skipping\n", tumbler_file_info_get_uri (infos[n]));
+          continue;
+        }
+      }
+      else
+      {
+        g_warning ("Failed to get filename from uri for '%s', skipping\n", tumbler_file_info_get_uri (infos[n]));
+        continue;
+      }
+
       /* determine the URI scheme and generate a hash key */
       gfile = g_file_new_for_uri (tumbler_file_info_get_uri (infos[n]));
       scheme = g_file_get_uri_scheme (gfile);