[gimp] libgimpconfig: support "compat enums" in gimp_config_deserialize_enum()

[Michael Natterer <mitch src gnome org>]

commit 7ab80eaa09fd8e01964b2d8dae5367cd99022fbd
Author: Michael Natterer <mitch gimp org>
Date:   Fri Jan 6 23:09:39 2017 +0100

    libgimpconfig: support "compat enums" in gimp_config_deserialize_enum()
    
    If the enum value is not found among the nicks and names of the
    GParamSpec's actual enum type, check if it has a "gimp-compat-enum"
    GType attached as QData, and try the lookup there.

 libgimpconfig/gimpconfig-deserialize.c |   33 +++++++++++++++++++++++++++++--
 1 files changed, 30 insertions(+), 3 deletions(-)
---
diff --git a/libgimpconfig/gimpconfig-deserialize.c b/libgimpconfig/gimpconfig-deserialize.c
index c1a8b1e..7bc45bb 100644
--- a/libgimpconfig/gimpconfig-deserialize.c
+++ b/libgimpconfig/gimpconfig-deserialize.c
@@ -530,11 +530,38 @@ gimp_config_deserialize_enum (GValue     *value,
 
       enum_value = g_enum_get_value_by_nick (enum_class,
                                              scanner->value.v_identifier);
-      if (!enum_value)
+      if (! enum_value)
         enum_value = g_enum_get_value_by_name (enum_class,
                                                scanner->value.v_identifier);
+      if (! enum_value)
+        {
+          /*  if the value was not found, check if we have a compat
+           *  enum to find the ideitifier
+           */
+          GQuark quark       = g_quark_from_static_string ("gimp-compat-enum");
+          GType  compat_type = (GType) g_param_spec_get_qdata (prop_spec, quark);
+
+          if (compat_type)
+            {
+              GEnumClass *compat_class = g_type_class_ref (compat_type);
+
+              enum_value = g_enum_get_value_by_nick (compat_class,
+                                                     scanner->value.v_identifier);
+              if (! enum_value)
+                enum_value = g_enum_get_value_by_name (compat_class,
+                                                       scanner->value.v_identifier);
+
+              /*  finally, if we found a compat value, make sure the
+               *  same value exists in the original enum
+               */
+              if (enum_value)
+                enum_value = g_enum_get_value (enum_class, enum_value->value);
+
+              g_type_class_unref (compat_class);
+           }
+        }
 
-      if (!enum_value)
+      if (! enum_value)
         {
           g_scanner_error (scanner,
                            _("invalid value '%s' for token %s"),
@@ -549,7 +576,7 @@ gimp_config_deserialize_enum (GValue     *value,
       enum_value = g_enum_get_value (enum_class,
                                      (gint) scanner->value.v_int64);
 
-      if (!enum_value)
+      if (! enum_value)
         {
           g_scanner_error (scanner,
                            _("invalid value '%ld' for token %s"),