Implement finalizers for module functions (Bug#30373)

* src/module-env-28.h: Add new module environment functions to
module environment for Emacs 28.

* src/emacs-module.h.in: Document that 'emacs_finalizer' also works
for function finalizers.

* src/emacs-module.c (CHECK_MODULE_FUNCTION): New function.
(struct Lisp_Module_Function): Add finalizer data member.
(module_make_function): Initialize finalizer.
(module_get_function_finalizer)
(module_set_function_finalizer): New module environment functions.
(module_finalize_function): New function.
(initialize_environment): Initialize new environment functions.

* src/alloc.c (cleanup_vector): Call potential module function
finalizer during garbage collection.

* test/data/emacs-module/mod-test.c (signal_error): New helper
function.
(memory_full): Use it.
(finalizer): New example function finalizer.
(Fmod_test_make_function_with_finalizer)
(Fmod_test_function_finalizer_calls): New test module functions.
(emacs_module_init): Define them.

* test/src/emacs-module-tests.el (module/function-finalizer): New unit
test.

* doc/lispref/internals.texi (Module Functions): Document new
functionality.
(Module Misc): Move description of 'emacs_finalizer' type to 'Module
Functions' node, and add a reference to it.

* etc/NEWS: Mention new functionality.

1 files changed, 47 insertions, 2 deletions

diff --git a/test/data/emacs-module/mod-test.c b/test/data/emacs-module/mod-test.c
index 8dc9ff144af..1a0a879a1bc 100644
--- a/test/data/emacs-module/mod-test.c
+++ b/test/data/emacs-module/mod-test.c
@@ -373,15 +373,20 @@ Fmod_test_add_nanosecond (emacs_env *env, ptrdiff_t nargs, emacs_value *args,
 }
 
 static void
-memory_full (emacs_env *env)
+signal_error (emacs_env *env, const char *message)
 {
-  const char *message = "Memory exhausted";
   emacs_value data = env->make_string (env, message, strlen (message));
   env->non_local_exit_signal (env, env->intern (env, "error"),
                               env->funcall (env, env->intern (env, "list"), 1,
                                             &data));
 }
 
+static void
+memory_full (emacs_env *env)
+{
+  signal_error (env, "Memory exhausted");
+}
+
 enum
 {
   max_count = ((SIZE_MAX < PTRDIFF_MAX ? SIZE_MAX : PTRDIFF_MAX)
@@ -490,6 +495,42 @@ Fmod_test_double (emacs_env *env, ptrdiff_t nargs, emacs_value *args,
   return result;
 }
 
+static int function_data;
+static int finalizer_calls_with_correct_data;
+static int finalizer_calls_with_incorrect_data;
+
+static void
+finalizer (void *data)
+{
+  if (data == &function_data)
+    ++finalizer_calls_with_correct_data;
+  else
+    ++finalizer_calls_with_incorrect_data;
+}
+
+static emacs_value
+Fmod_test_make_function_with_finalizer (emacs_env *env, ptrdiff_t nargs,
+                                        emacs_value *args, void *data)
+{
+  emacs_value fun
+    = env->make_function (env, 2, 2, Fmod_test_sum, NULL, &function_data);
+  env->set_function_finalizer (env, fun, finalizer);
+  if (env->get_function_finalizer (env, fun) != finalizer)
+    signal_error (env, "Invalid finalizer");
+  return fun;
+}
+
+static emacs_value
+Fmod_test_function_finalizer_calls (emacs_env *env, ptrdiff_t nargs,
+                                    emacs_value *args, void *data)
+{
+  emacs_value Flist = env->intern (env, "list");
+  emacs_value list_args[]
+    = {env->make_integer (env, finalizer_calls_with_correct_data),
+       env->make_integer (env, finalizer_calls_with_incorrect_data)};
+  return env->funcall (env, Flist, 2, list_args);
+}
+
 /* Lisp utilities for easier readability (simple wrappers).  */
 
 /* Provide FEATURE to Emacs.  */
@@ -566,6 +607,10 @@ emacs_module_init (struct emacs_runtime *ert)
   DEFUN ("mod-test-add-nanosecond", Fmod_test_add_nanosecond, 1, 1, NULL, NULL);
   DEFUN ("mod-test-nanoseconds", Fmod_test_nanoseconds, 1, 1, NULL, NULL);
   DEFUN ("mod-test-double", Fmod_test_double, 1, 1, NULL, NULL);
+  DEFUN ("mod-test-make-function-with-finalizer",
+         Fmod_test_make_function_with_finalizer, 0, 0, NULL, NULL);
+  DEFUN ("mod-test-function-finalizer-calls",
+         Fmod_test_function_finalizer_calls, 0, 0, NULL, NULL);
 
 #undef DEFUN