[gimp/wip/Jehan/classy-GIMP: 37/65] libgimp: allow object GimpImage as procedure parameter.

[Jehan <jehanp src gnome org>]

commit 9845f86a1920194c8f57c241ce4b10afb55096b5
Author: Jehan <jehan girinstud io>
Date:   Tue Aug 13 12:34:09 2019 +0200

    libgimp: allow object GimpImage as procedure parameter.
    
    Though it is still possible to use an image ID as procedure parameter,
    it is now possible to pass a GimpImage GParamSpecObject.
    
    Over the wire, this will transform back and forth into a GimpImageID,
    totally transparently for the plug-in which will only always get a
    GimpImage.

 libgimp/gimpgpparams-body.c | 17 +++++++++++++++++
 libgimp/gimpprocedure.c     | 35 +++++++++++++++++++++++++----------
 libgimp/gimpprocedure.h     |  2 +-
 3 files changed, 43 insertions(+), 11 deletions(-)
---
diff --git a/libgimp/gimpgpparams-body.c b/libgimp/gimpgpparams-body.c
index 9edbdac9e2..457b1ecca2 100644
--- a/libgimp/gimpgpparams-body.c
+++ b/libgimp/gimpgpparams-body.c
@@ -172,6 +172,23 @@ _gimp_param_spec_to_gp_param_def (GParamSpec *pspec,
       param_def->meta.m_param_def.type_name =
         (gchar *) g_type_name (G_PARAM_SPEC_VALUE_TYPE (pspec));
     }
+  else if (pspec_type == G_TYPE_PARAM_OBJECT)
+    {
+      /* We can't pass objects over the wire, but we can support
+       * specific objects which are actually handled in the core through
+       * IDs by converting these types to their respective IDs.
+       */
+
+      /* Don't compare with libgimp types directly as this file is also
+       * included from app/ which won't know of the types.
+       */
+      if (g_strcmp0 (g_type_name (pspec->value_type), "GimpImage") == 0)
+        {
+          param_def->type_name = "GimpParamImageID";
+          param_def->param_def_type = GP_PARAM_DEF_TYPE_ID;
+          param_def->meta.m_id.none_ok = TRUE;
+        }
+    }
 }
 
 void
diff --git a/libgimp/gimpprocedure.c b/libgimp/gimpprocedure.c
index d36e4c4fd8..9e2063aef5 100644
--- a/libgimp/gimpprocedure.c
+++ b/libgimp/gimpprocedure.c
@@ -105,7 +105,7 @@ static GimpValueArray *
 static gboolean   gimp_procedure_validate_args  (GimpProcedure        *procedure,
                                                  GParamSpec          **param_specs,
                                                  gint                  n_param_specs,
-                                                 const GimpValueArray *args,
+                                                 GimpValueArray       *args,
                                                  gboolean              return_vals,
                                                  GError              **error);
 
@@ -1293,8 +1293,8 @@ gimp_procedure_new_return_values (GimpProcedure     *procedure,
  * Since: 3.0
  **/
 GimpValueArray *
-gimp_procedure_run (GimpProcedure        *procedure,
-                    const GimpValueArray *args)
+gimp_procedure_run (GimpProcedure  *procedure,
+                    GimpValueArray *args)
 {
   GimpValueArray *return_vals;
   GError         *error = NULL;
@@ -1409,12 +1409,12 @@ gimp_procedure_extension_ready (GimpProcedure *procedure)
 /*  private functions  */
 
 static gboolean
-gimp_procedure_validate_args (GimpProcedure         *procedure,
-                              GParamSpec           **param_specs,
-                              gint                   n_param_specs,
-                              const GimpValueArray  *args,
-                              gboolean               return_vals,
-                              GError               **error)
+gimp_procedure_validate_args (GimpProcedure   *procedure,
+                              GParamSpec     **param_specs,
+                              gint             n_param_specs,
+                              GimpValueArray  *args,
+                              gboolean         return_vals,
+                              GError         **error)
 {
   gint i;
 
@@ -1425,7 +1425,22 @@ gimp_procedure_validate_args (GimpProcedure         *procedure,
       GType       arg_type  = G_VALUE_TYPE (arg);
       GType       spec_type = G_PARAM_SPEC_VALUE_TYPE (pspec);
 
-      if (arg_type != spec_type)
+      /* As a special case, validation can transform IDs into their
+       * respective object.
+       */
+      if (arg_type == GIMP_TYPE_IMAGE_ID &&
+          spec_type == GIMP_TYPE_IMAGE)
+        {
+          GValue     value = G_VALUE_INIT;
+          GimpImage *image = gimp_image_new_by_id (g_value_get_int (arg));
+
+          g_value_init (&value, GIMP_TYPE_IMAGE);
+          g_value_take_object (&value, image);
+          gimp_value_array_remove (args, i);
+          gimp_value_array_insert (args, i, &value);
+          g_value_unset (&value);
+        }
+      else if (arg_type != spec_type)
         {
           if (return_vals)
             {
diff --git a/libgimp/gimpprocedure.h b/libgimp/gimpprocedure.h
index 4de5c72b97..c9d97e3212 100644
--- a/libgimp/gimpprocedure.h
+++ b/libgimp/gimpprocedure.h
@@ -166,7 +166,7 @@ GimpValueArray * gimp_procedure_new_return_values  (GimpProcedure        *proced
                                                     GError               *error);
 
 GimpValueArray * gimp_procedure_run                (GimpProcedure        *procedure,
-                                                    const GimpValueArray *args);
+                                                    GimpValueArray       *args);
 
 void             gimp_procedure_extension_ready    (GimpProcedure        *procedure);