[gimp] libgimpbase: fix gimp_metadata_set_from_xmp() to really expect XMP

[Michael Natterer <mitch src gnome org>]

commit e5a669bdfc7cebfaa48879bc6ee4e65bea10f71a
Author: Michael Natterer <mitch gimp org>
Date:   Fri Apr 22 22:49:06 2016 +0200

    libgimpbase: fix gimp_metadata_set_from_xmp() to really expect XMP
    
    Don't skip the first 10 bytes. That code was there to skip the magic
    "GIMP_XMP_1" of the old "gimp-metadata" parasite. Instead, properly
    check for that magic in xcf_load_image() and pass only the actual XMP
    to gimp_metadata_set_from_xmp(). Also remove the +10 hack in file-exr.

 app/xcf/xcf-load.c           |   16 +++++++++++++---
 libgimpbase/gimpmetadata.c   |    3 ---
 plug-ins/file-exr/file-exr.c |   22 ++++++++++------------
 3 files changed, 23 insertions(+), 18 deletions(-)
---
diff --git a/app/xcf/xcf-load.c b/app/xcf/xcf-load.c
index b431262..82ef7e5 100644
--- a/app/xcf/xcf-load.c
+++ b/app/xcf/xcf-load.c
@@ -321,7 +321,9 @@ xcf_load_image (Gimp     *gimp,
                                        "gimp-metadata");
   if (parasite)
     {
-      GimpImagePrivate *private = GIMP_IMAGE_GET_PRIVATE (image);
+      GimpImagePrivate *private    = GIMP_IMAGE_GET_PRIVATE (image);
+      const gchar      *xmp_data   = gimp_parasite_data (parasite);
+      gint              xmp_length = gimp_parasite_data_size (parasite);
 
       if (has_metadata)
         {
@@ -329,6 +331,14 @@ xcf_load_image (Gimp     *gimp,
                       "has both 'gimp-image-metadata' and 'gimp-metadata' "
                       "parasites, dropping old 'gimp-metadata'\n");
         }
+      else if (xmp_length < 14 ||
+               strncmp (xmp_data, "GIMP_XMP_1", 10) != 0)
+        {
+          gimp_message (gimp, G_OBJECT (info->progress),
+                        GIMP_MESSAGE_WARNING,
+                        _("Corrupt 'gimp-metadata' parasite discovered.\n"
+                          "XMP data could not be migrated."));
+        }
       else
         {
           GimpMetadata *metadata = gimp_image_get_metadata (image);
@@ -340,8 +350,8 @@ xcf_load_image (Gimp     *gimp,
             metadata = gimp_metadata_new ();
 
           if (! gimp_metadata_set_from_xmp (metadata,
-                                            gimp_parasite_data (parasite),
-                                            gimp_parasite_data_size (parasite),
+                                            (const guint8 *) xmp_data + 10,
+                                            xmp_length - 10,
                                             &my_error))
             {
               gimp_message (gimp, G_OBJECT (info->progress),
diff --git a/libgimpbase/gimpmetadata.c b/libgimpbase/gimpmetadata.c
index 14e8273..8da75a7 100644
--- a/libgimpbase/gimpmetadata.c
+++ b/libgimpbase/gimpmetadata.c
@@ -694,9 +694,6 @@ gimp_metadata_set_from_xmp (GimpMetadata  *metadata,
   g_return_val_if_fail (xmp_data_length > 0, FALSE);
   g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
 
-  xmp_data        += 10;
-  xmp_data_length -= 10;
-
   xmp_metadata = gimp_metadata_new ();
 
   if (! gexiv2_metadata_open_buf (xmp_metadata,
diff --git a/plug-ins/file-exr/file-exr.c b/plug-ins/file-exr/file-exr.c
index 4a2c053..9845725 100644
--- a/plug-ins/file-exr/file-exr.c
+++ b/plug-ins/file-exr/file-exr.c
@@ -361,16 +361,14 @@ load_image (const gchar  *filename,
   xmp_data = exr_loader_get_xmp (loader, &xmp_size);
   if (xmp_data)
     {
-      // FIXME:
-      // gimp_metadata_set_from_xmp skips the first 10 bytes.
-      // working around that like this might not be the right thing to do!
       if (gimp_metadata_set_from_xmp (metadata,
-                                      xmp_data - 10,
-                                      xmp_size + 10,
+                                      xmp_data,
+                                      xmp_size,
                                       NULL))
         {
           have_metadata = TRUE;
         }
+
       g_free (xmp_data);
     }
 
@@ -407,13 +405,13 @@ static void
 exr_load_sanitize_comment (gchar *comment)
 {
   if (! g_utf8_validate (comment, -1, NULL))
-  {
-    gchar *c;
-
-    for (c = comment; *c; c++)
     {
-      if (*c > 126 || (*c < 32 && *c != '\t' && *c != '\n' && *c != '\r'))
-        *c = '?';
+      gchar *c;
+
+      for (c = comment; *c; c++)
+        {
+          if (*c > 126 || (*c < 32 && *c != '\t' && *c != '\n' && *c != '\r'))
+            *c = '?';
+        }
     }
-  }
 }