[gimp] plug-ins: in script-fu, don't query PDB procedures' info on startup

[Ell <ell src gnome org>]

commit 9a2999a553c59927bef382b28d4ec2cf8ac8ce1a
Author: Ell <ell_se yahoo com>
Date:   Wed Sep 26 14:28:34 2018 -0400

    plug-ins: in script-fu, don't query PDB procedures' info on startup
    
    script-fu used to query the information of every PDB procedure on
    startup, in order to get the number of parameters for each
    procedure.  This was done so that nullary procedures were defined
    in such a way as to accept (and ignore) any number of arguments
    (and at least one of the scripts we ship relies on this behavior).
    However, this requires expensive back-and-forth communication with
    the main GIMP process, which notable slowed down script-fu's
    startup, and had a non-negligible impact on GIMP's startup time.
    
    Instead, avoid querying procedure information, and implement the
    special behavior for nullary procedures at call time.  We do this
    by defining, in addition to the "strict" gimp-proc-db-call
    procedure, a "permissive" -gimp-proc-db-call internal procedure,
    and using the latter to call the predefined PDB procedures.

 plug-ins/script-fu/scheme-wrapper.c | 149 +++++++++++++++++-------------------
 1 file changed, 70 insertions(+), 79 deletions(-)
---
diff --git a/plug-ins/script-fu/scheme-wrapper.c b/plug-ins/script-fu/scheme-wrapper.c
index 1d1095af1c..69e22c0d39 100644
--- a/plug-ins/script-fu/scheme-wrapper.c
+++ b/plug-ins/script-fu/scheme-wrapper.c
@@ -49,28 +49,33 @@
 
 #undef cons
 
-static void     ts_init_constants                (scheme    *sc);
-static void     ts_init_enum                     (scheme    *sc,
-                                                  GType      enum_type);
-static void     ts_init_procedures               (scheme    *sc,
-                                                  gboolean   register_scipts);
-static void     convert_string                   (gchar     *str);
-static pointer  script_fu_marshal_procedure_call (scheme    *sc,
-                                                  pointer    a);
-static void     script_fu_marshal_destroy_args   (GimpParam *params,
-                                                  gint       n_params);
-
-static pointer  script_fu_register_call          (scheme    *sc,
-                                                  pointer    a);
-static pointer  script_fu_menu_register_call     (scheme    *sc,
-                                                  pointer    a);
-static pointer  script_fu_quit_call              (scheme    *sc,
-                                                  pointer    a);
-static pointer  script_fu_nil_call               (scheme    *sc,
-                                                  pointer    a);
-
-static gboolean ts_load_file                     (const gchar *dirname,
-                                                  const gchar *basename);
+static void     ts_init_constants                           (scheme    *sc);
+static void     ts_init_enum                                (scheme    *sc,
+                                                             GType      enum_type);
+static void     ts_init_procedures                          (scheme    *sc,
+                                                             gboolean   register_scipts);
+static void     convert_string                              (gchar     *str);
+static pointer  script_fu_marshal_procedure_call            (scheme    *sc,
+                                                             pointer    a,
+                                                             gboolean   permissive);
+static pointer  script_fu_marshal_procedure_call_strict     (scheme    *sc,
+                                                             pointer    a);
+static pointer  script_fu_marshal_procedure_call_permissive (scheme    *sc,
+                                                             pointer    a);
+static void     script_fu_marshal_destroy_args              (GimpParam *params,
+                                                             gint       n_params);
+
+static pointer  script_fu_register_call                     (scheme    *sc,
+                                                             pointer    a);
+static pointer  script_fu_menu_register_call                (scheme    *sc,
+                                                             pointer    a);
+static pointer  script_fu_quit_call                         (scheme    *sc,
+                                                             pointer    a);
+static pointer  script_fu_nil_call                          (scheme    *sc,
+                                                             pointer    a);
+
+static gboolean ts_load_file                                (const gchar *dirname,
+                                                             const gchar *basename);
 
 typedef struct
 {
@@ -433,7 +438,14 @@ ts_init_procedures (scheme   *sc,
   symbol = sc->vptr->mk_symbol (sc, "gimp-proc-db-call");
   sc->vptr->scheme_define (sc, sc->global_env, symbol,
                            sc->vptr->mk_foreign_func (sc,
-                                                      script_fu_marshal_procedure_call));
+                                                      script_fu_marshal_procedure_call_strict));
+  sc->vptr->setimmutable (symbol);
+
+  /*  register the internal database execution procedure; see comment below  */
+  symbol = sc->vptr->mk_symbol (sc, "-gimp-proc-db-call");
+  sc->vptr->scheme_define (sc, sc->global_env, symbol,
+                           sc->vptr->mk_foreign_func (sc,
+                                                      script_fu_marshal_procedure_call_permissive));
   sc->vptr->setimmutable (symbol);
 
   gimp_procedural_db_query (".*", ".*", ".*", ".*", ".*", ".*", ".*",
@@ -442,61 +454,24 @@ ts_init_procedures (scheme   *sc,
   /*  Register each procedure as a scheme func  */
   for (i = 0; i < num_procs; i++)
     {
-      gchar           *proc_blurb;
-      gchar           *proc_help;
-      gchar           *proc_author;
-      gchar           *proc_copyright;
-      gchar           *proc_date;
-      GimpPDBProcType  proc_type;
-      gint             n_params;
-      gint             n_return_vals;
-      GimpParamDef    *params;
-      GimpParamDef    *return_vals;
-
-      /*  lookup the procedure  */
-      if (gimp_procedural_db_proc_info (proc_list[i],
-                                        &proc_blurb,
-                                        &proc_help,
-                                        &proc_author,
-                                        &proc_copyright,
-                                        &proc_date,
-                                        &proc_type,
-                                        &n_params, &n_return_vals,
-                                        &params, &return_vals))
-        {
-          gchar *buff;
-
-          /* Build a define that will call the foreign function.
-           * The Scheme statement was suggested by Simon Budig.
-           */
-          if (n_params == 0)
-            {
-              buff = g_strdup_printf (" (define (%s)"
-                                      " (gimp-proc-db-call \"%s\"))",
-                                      proc_list[i], proc_list[i]);
-            }
-          else
-            {
-              buff = g_strdup_printf (" (define %s (lambda x"
-                                      " (apply gimp-proc-db-call (cons \"%s\" x))))",
-                                      proc_list[i], proc_list[i]);
-            }
-
-          /*  Execute the 'define'  */
-          sc->vptr->load_string (sc, buff);
-
-          g_free (buff);
+      gchar *buff;
+
+      /* Build a define that will call the foreign function.
+       * The Scheme statement was suggested by Simon Budig.
+       *
+       * We call the procedure through -gimp-proc-db-call, which is a more
+       * permissive version of gimp-proc-db-call, that accepts (and ignores)
+       * any number of arguments for nullary procedures, for backward
+       * compatibility.
+       */
+      buff = g_strdup_printf (" (define (%s . args)"
+                              " (apply -gimp-proc-db-call \"%s\" args))",
+                              proc_list[i], proc_list[i]);
 
-          /*  free the queried information  */
-          g_free (proc_blurb);
-          g_free (proc_help);
-          g_free (proc_author);
-          g_free (proc_copyright);
-          g_free (proc_date);
+      /*  Execute the 'define'  */
+      sc->vptr->load_string (sc, buff);
 
-          gimp_destroy_paramdefs (params, n_params);
-          gimp_destroy_paramdefs (return_vals, n_return_vals);
-        }
+      g_free (buff);
     }
 
   g_strfreev (proc_list);
@@ -538,8 +513,9 @@ convert_string (gchar *str)
 
 /* This is called by the Scheme interpreter to allow calls to GIMP functions */
 static pointer
-script_fu_marshal_procedure_call (scheme  *sc,
-                                  pointer  a)
+script_fu_marshal_procedure_call (scheme   *sc,
+                                  pointer   a,
+                                  gboolean  permissive)
 {
   GimpParam       *args;
   GimpParam       *values = NULL;
@@ -631,7 +607,8 @@ script_fu_marshal_procedure_call (scheme  *sc,
     }
 
   /*  Check the supplied number of arguments  */
-  if ((sc->vptr->list_length (sc, a) - 1) != nparams)
+  if ((nparams > 0 || ! permissive) &&
+      (sc->vptr->list_length (sc, a) - 1) != nparams)
     {
 #if DEBUG_MARSHALL
       g_printerr ("  Invalid number of arguments (expected %d but received %d)",
@@ -1587,6 +1564,20 @@ script_fu_marshal_procedure_call (scheme  *sc,
   return return_val;
 }
 
+static pointer
+script_fu_marshal_procedure_call_strict (scheme  *sc,
+                                         pointer  a)
+{
+  return script_fu_marshal_procedure_call (sc, a, FALSE);
+}
+
+static pointer
+script_fu_marshal_procedure_call_permissive (scheme  *sc,
+                                             pointer  a)
+{
+  return script_fu_marshal_procedure_call (sc, a, TRUE);
+}
+
 static void
 script_fu_marshal_destroy_args (GimpParam *params,
                                 gint       n_params)