app: add a small infrastructure to validate known parasites

when they are added to items, images or globally, from the PDF or an
XCF file. None of the validation functions does anything currently,
they simply return TRUE.

app/core/gimp-parasites.c

@@ -28,6 +28,18 @@
 #include "gimpparasitelist.h"
 
 
+gboolean
+gimp_parasite_validate (Gimp                *gimp,
+                        const GimpParasite  *parasite,
+                        GError             **error)
+{
+  g_return_val_if_fail (GIMP_IS_GIMP (gimp), FALSE);
+  g_return_val_if_fail (parasite != NULL, FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  return TRUE;
+}
+
 void
 gimp_parasite_attach (Gimp               *gimp,
                       const GimpParasite *parasite)

app/core/gimp-parasites.h

@@ -20,6 +20,9 @@
 
 /* some wrappers to access gimp->parasites, mainly for the PDB */
 
+gboolean              gimp_parasite_validate     (Gimp               *gimp,
+                                                  const GimpParasite *parasite,
+                                                  GError            **error);
 void                  gimp_parasite_attach       (Gimp               *gimp,
                                                   const GimpParasite *parasite);
 void                  gimp_parasite_detach       (Gimp               *gimp,

app/core/gimpimage.c

@@ -3050,6 +3050,18 @@ gimp_image_parasite_list (const GimpImage *image,
   return list;
 }
 
+gboolean
+gimp_image_parasite_validate (GimpImage           *image,
+                              const GimpParasite  *parasite,
+                              GError             **error)
+{
+  g_return_val_if_fail (GIMP_IS_IMAGE (image), FALSE);
+  g_return_val_if_fail (parasite != NULL, FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  return TRUE;
+}
+
 void
 gimp_image_parasite_attach (GimpImage          *image,
                             const GimpParasite *parasite)

app/core/gimpimage.h

@@ -286,6 +286,9 @@ const GimpParasite * gimp_image_parasite_find    (const GimpImage    *image,
                                                   const gchar        *name);
 gchar        ** gimp_image_parasite_list         (const GimpImage    *image,
                                                   gint               *count);
+gboolean        gimp_image_parasite_validate     (GimpImage           *image,
+                                                  const GimpParasite  *parasite,
+                                                  GError             **error);
 void            gimp_image_parasite_attach       (GimpImage          *image,
                                                   const GimpParasite *parasite);
 void            gimp_image_parasite_detach       (GimpImage          *image,

app/core/gimpitem.c

@@ -1798,6 +1798,18 @@ gimp_item_get_parasites (const GimpItem *item)
   return GET_PRIVATE (item)->parasites;
 }
 
+gboolean
+gimp_item_parasite_validate (GimpItem            *item,
+                             const GimpParasite  *parasite,
+                             GError             **error)
+{
+  g_return_val_if_fail (GIMP_IS_ITEM (item), FALSE);
+  g_return_val_if_fail (parasite != NULL, FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  return TRUE;
+}
+
 void
 gimp_item_parasite_attach (GimpItem           *item,
                            const GimpParasite *parasite,

app/core/gimpitem.h

@@ -274,6 +274,9 @@ void               gimp_item_set_parasites   (GimpItem           *item,
                                               GimpParasiteList   *parasites);
 GimpParasiteList * gimp_item_get_parasites   (const GimpItem     *item);
 
+gboolean        gimp_item_parasite_validate  (GimpItem           *item,
+                                              const GimpParasite *parasite,
+                                              GError            **error);
 void            gimp_item_parasite_attach    (GimpItem           *item,
                                               const GimpParasite *parasite,
                                               gboolean            push_undo);

app/pdb/gimp-cmds.c

@@ -114,7 +114,10 @@ attach_parasite_invoker (GimpProcedure         *procedure,
 
   if (success)
     {
-      gimp_parasite_attach (gimp, parasite);
+      if (gimp_parasite_validate (gimp, parasite, error))
+        gimp_parasite_attach (gimp, parasite);
+      else
+        success = FALSE;
     }
 
   return gimp_procedure_get_return_values (procedure, success,

app/pdb/image-cmds.c

@@ -2833,7 +2833,10 @@ image_attach_parasite_invoker (GimpProcedure         *procedure,
 
   if (success)
     {
-      gimp_image_parasite_attach (image, parasite);
+      if (gimp_image_parasite_validate (image, parasite, error))
+        gimp_image_parasite_attach (image, parasite);
+      else
+        success = FALSE;
     }
 
   return gimp_procedure_get_return_values (procedure, success,

app/pdb/item-cmds.c

@@ -785,7 +785,10 @@ item_attach_parasite_invoker (GimpProcedure         *procedure,
 
   if (success)
     {
-      gimp_item_parasite_attach (item, parasite, TRUE);
+      if (gimp_item_parasite_validate (item, parasite, error))
+        gimp_item_parasite_attach (item, parasite, TRUE);
+      else
+        success = FALSE;
     }
 
   return gimp_procedure_get_return_values (procedure, success,

app/xcf/xcf-load.c

@@ -753,12 +753,25 @@ xcf_load_image_props (XcfInfo   *info,
 
             while (info->cp - base < prop_size)
               {
-                GimpParasite *p = xcf_load_parasite (info);
+                GimpParasite *p     = xcf_load_parasite (info);
+                GError       *error = NULL;
 
                 if (! p)
                   return FALSE;
 
-                gimp_image_parasite_attach (image, p);
+                if (! gimp_image_parasite_validate (image, p, &error))
+                  {
+                    gimp_message (info->gimp, G_OBJECT (info->progress),
+                                  GIMP_MESSAGE_WARNING,
+                                  "Warning, invalid image parasite in XCF file: %s",
+                                  error->message);
+                    g_clear_error (&error);
+                  }
+                else
+                  {
+                    gimp_image_parasite_attach (image, p);
+                  }
+
                 gimp_parasite_free (p);
               }
 
@@ -1026,12 +1039,25 @@ xcf_load_layer_props (XcfInfo    *info,
 
             while (info->cp - base < prop_size)
               {
-                GimpParasite *p = xcf_load_parasite (info);
+                GimpParasite *p     = xcf_load_parasite (info);
+                GError       *error = NULL;
 
                 if (! p)
                   return FALSE;
 
-                gimp_item_parasite_attach (GIMP_ITEM (*layer), p, FALSE);
+                if (! gimp_item_parasite_validate (GIMP_ITEM (*layer), p, &error))
+                  {
+                    gimp_message (info->gimp, G_OBJECT (info->progress),
+                                  GIMP_MESSAGE_WARNING,
+                                  "Warning, invalid layer parasite in XCF file: %s",
+                                  error->message);
+                    g_clear_error (&error);
+                  }
+                else
+                  {
+                    gimp_item_parasite_attach (GIMP_ITEM (*layer), p, FALSE);
+                  }
+
                 gimp_parasite_free (p);
               }
 
@@ -1222,12 +1248,26 @@ xcf_load_channel_props (XcfInfo      *info,
 
             while ((info->cp - base) < prop_size)
               {
-                GimpParasite *p = xcf_load_parasite (info);
+                GimpParasite *p     = xcf_load_parasite (info);
+                GError       *error = NULL;
 
                 if (! p)
                   return FALSE;
 
-                gimp_item_parasite_attach (GIMP_ITEM (*channel), p, FALSE);
+                if (! gimp_item_parasite_validate (GIMP_ITEM (*channel), p,
+                                                    &error))
+                  {
+                    gimp_message (info->gimp, G_OBJECT (info->progress),
+                                  GIMP_MESSAGE_WARNING,
+                                  "Warning, invalid channel parasite in XCF file: %s",
+                                  error->message);
+                    g_clear_error (&error);
+                  }
+                else
+                  {
+                    gimp_item_parasite_attach (GIMP_ITEM (*channel), p, FALSE);
+                  }
+
                 gimp_parasite_free (p);
               }
 
@@ -2148,11 +2188,24 @@ xcf_load_vector (XcfInfo   *info,
   for (i = 0; i < num_parasites; i++)
     {
       GimpParasite *parasite = xcf_load_parasite (info);
+      GError       *error    = NULL;
 
       if (! parasite)
         return FALSE;
 
-      gimp_item_parasite_attach (GIMP_ITEM (vectors), parasite, FALSE);
+      if (! gimp_item_parasite_validate (GIMP_ITEM (vectors), parasite, &error))
+        {
+          gimp_message (info->gimp, G_OBJECT (info->progress),
+                        GIMP_MESSAGE_WARNING,
+                        "Warning, invalid vectors parasite in XCF file: %s",
+                        error->message);
+          g_clear_error (&error);
+        }
+      else
+        {
+          gimp_item_parasite_attach (GIMP_ITEM (vectors), parasite, FALSE);
+        }
+
       gimp_parasite_free (parasite);
     }
 

tools/pdbgen/pdb/gimp.pdb

@@ -106,7 +106,10 @@ HELP
     %invoke = (
 	code => <<'CODE'
 {
-  gimp_parasite_attach (gimp, parasite);
+  if (gimp_parasite_validate (gimp, parasite, error))
+    gimp_parasite_attach (gimp, parasite);
+  else
+    success = FALSE;
 }
 CODE
     );

tools/pdbgen/pdb/image.pdb

@@ -2862,7 +2862,10 @@ HELP
     %invoke = (
         code => <<'CODE'
 {
-  gimp_image_parasite_attach (image, parasite);
+  if (gimp_image_parasite_validate (image, parasite, error))
+    gimp_image_parasite_attach (image, parasite);
+  else
+    success = FALSE;
 }
 CODE
     );

tools/pdbgen/pdb/item.pdb

@@ -753,7 +753,10 @@ HELP
     %invoke = (
 	code => <<'CODE'
 {
-  gimp_item_parasite_attach (item, parasite, TRUE);
+  if (gimp_item_parasite_validate (item, parasite, error))
+    gimp_item_parasite_attach (item, parasite, TRUE);
+  else
+    success = FALSE;
 }
 CODE
     );