mruby-exit.c: make exit() to raise SystemExit exception.

Now it allows error handlers to work, unlike `exit!`.

include/mruby/error.h

@@ -21,6 +21,14 @@ struct RException {
   struct RObject *backtrace;    // NULL, RArray or RData
 };
 
+/* error that should terminate execution */
+#define MRB_EXC_EXIT 65536
+#define MRB_EXC_EXIT_P(e) ((e)->flags & MRB_EXC_EXIT)
+/* retrieve status value from exc; need <mruby/variable.h> and <mruby/presym.h> */
+#define MRB_EXC_EXIT_STATUS(mrb,e) ((int)mrb_as_int((mrb),mrb_obj_iv_get((mrb),(e),MRB_SYM(status))))
+/* exit with SystemExit status */
+#define MRB_EXC_CHECK_EXIT(mrb,e) do {if (MRB_EXC_EXIT_P(e)) exit(MRB_EXC_EXIT_STATUS((mrb),(e)));} while (0)
+
 #define mrb_exc_ptr(v) ((struct RException*)mrb_ptr(v))
 
 MRB_API mrb_noreturn void mrb_sys_fail(mrb_state *mrb, const char *mesg);

mrbgems/mruby-bin-mirb/tools/mirb/mirb.c

@@ -18,6 +18,7 @@
 #include <mruby/dump.h>
 #include <mruby/string.h>
 #include <mruby/variable.h>
+#include <mruby/error.h>
 #include <mruby/presym.h>
 
 #include <stdlib.h>
@@ -674,6 +675,7 @@ main(int argc, char **argv)
         stack_keep = proc->body.irep->nlocals;
         /* did an exception occur? */
         if (mrb->exc) {
+          MRB_EXC_CHECK_EXIT(mrb, mrb->exc);
           p(mrb, mrb_obj_value(mrb->exc), 0);
           mrb->exc = 0;
         }

mrbgems/mruby-bin-mruby/tools/mruby/mruby.c

@@ -11,6 +11,8 @@
 #include <mruby/dump.h>
 #include <mruby/variable.h>
 #include <mruby/proc.h>
+#include <mruby/error.h>
+#include <mruby/presym.h>
 
 #if defined(_WIN32) || defined(_WIN64)
 # include <io.h> /* for setmode */
@@ -366,6 +368,7 @@ main(int argc, char **argv)
     mrb_gc_arena_restore(mrb, ai);
     mrbc_context_free(mrb, c);
     if (mrb->exc) {
+      MRB_EXC_CHECK_EXIT(mrb, mrb->exc);
       if (!mrb_undef_p(v)) {
         mrb_print_error(mrb);
       }

mrbgems/mruby-exit/src/mruby-exit.c

@@ -1,5 +1,8 @@
 #include <stdlib.h>
 #include <mruby.h>
+#include <mruby/error.h>
+#include <mruby/variable.h>
+#include <mruby/presym.h>
 
 #ifndef EXIT_SUCCESS
 # define EXIT_SUCCESS 0
@@ -9,48 +12,69 @@
 # define EXIT_FAILURE 1
 #endif
 
-/*
- *  call-seq:
- *     exit(status=false)
- *
- *  Exits the process immediately. No exit handlers are run currently.
- *  <em>status</em> is returned to the underlying system as the
- *  exit status.
- *
- *     exit(true)
- */
+static int
+get_status(mrb_state *mrb)
+{
+  mrb_value status = mrb_true_value();
+
+  mrb_get_args(mrb, "|o", &status);
+  if (mrb_true_p(status)) return EXIT_SUCCESS;
+  if (mrb_false_p(status)) return EXIT_FAILURE;
+  return (int)mrb_as_int(mrb, status);
+}
 
 /*
  *  call-seq:
- *     exit!(status=false)
+ *     exit(status=true)
+ *
+ *  Initiates the termination of the Ruby script by raising the
+ *  SystemExit exception. This exception may be caught. The
+ *  optional parameter is used to return a status code to the invoking
+ *  environment.
+ *
+ *  +true+ and +false+ of _status_ means success and failure
+ *  respectively.  The interpretation of other integer values are
+ *  system dependent.
+ *
+ *     exit(0)
+ */
+static mrb_value
+f_exit(mrb_state *mrb, mrb_value self)
+{
+  int status = get_status(mrb);
+  mrb_value exc = mrb_obj_new(mrb, mrb_exc_get_id(mrb, MRB_SYM(SystemExit)), 0, NULL);
+  struct RException *e = mrb_exc_ptr(exc);
+  e->flags |= MRB_EXC_EXIT;
+  mrb_iv_set(mrb, exc, MRB_SYM(status), mrb_int_value(mrb, (mrb_int)status));
+  mrb_exc_raise(mrb, exc);
+  /* not reached */
+  return mrb_nil_value();
+}
+
+/*
+ *  call-seq:
+ *     exit!(status=true)
  *
  *  Exits the process immediately. No exit handlers are run.
  *  <em>status</em> is returned to the underlying system as the
  *  exit status.
  *
- *     exit!(true)
+ *     exit!(0)
  */
 static mrb_value
 f_exit_bang(mrb_state *mrb, mrb_value self)
 {
-  mrb_value status = mrb_true_value();
-  int istatus;
-
-  mrb_get_args(mrb, "|o", &status);
-  istatus = mrb_true_p(status) ? EXIT_SUCCESS :
-            mrb_false_p(status) ? EXIT_FAILURE :
-            (int)mrb_int(mrb, status);
-  exit(istatus);
-
+  exit(get_status(mrb));
   /* not reached */
-  return status;
+  return mrb_nil_value();
 }
 
 void
 mrb_mruby_exit_gem_init(mrb_state* mrb)
 {
-  mrb_define_method(mrb, mrb->kernel_module, "exit", f_exit_bang, MRB_ARGS_OPT(1));
-  mrb_define_method(mrb, mrb->kernel_module, "exit!", f_exit_bang, MRB_ARGS_OPT(1));
+  mrb_define_class_id(mrb, MRB_SYM(SystemExit), mrb->eException_class);
+  mrb_define_method_id(mrb, mrb->kernel_module, MRB_SYM(exit), f_exit, MRB_ARGS_OPT(1));
+  mrb_define_method_id(mrb, mrb->kernel_module, MRB_SYM_B(exit), f_exit_bang, MRB_ARGS_OPT(1));
 }
 
 void