1 files changed, 138 insertions, 0 deletions
diff --git a/eval_jump.c b/eval_jump.c
new file mode 100644
index 0000000000..6ee8ff4a6f
--- /dev/null
+++ b/eval_jump.c
@@ -0,0 +1,138 @@
+/* -*-c-*- */
+/*
+ * from eval.c
+ */
+
+#include "eval_intern.h"
+
+/* exit */
+
+void
+rb_call_end_proc(VALUE data)
+{
+    rb_proc_call(data, rb_ary_new());
+}
+
+/*
+ *  call-seq:
+ *     at_exit { block } -> proc
+ *
+ *  Converts _block_ to a +Proc+ object (and therefore
+ *  binds it at the point of call) and registers it for execution when
+ *  the program exits. If multiple handlers are registered, they are
+ *  executed in reverse order of registration.
+ *
+ *     def do_at_exit(str1)
+ *       at_exit { print str1 }
+ *     end
+ *     at_exit { puts "cruel world" }
+ *     do_at_exit("goodbye ")
+ *     exit
+ *
+ *  <em>produces:</em>
+ *
+ *     goodbye cruel world
+ */
+
+static VALUE
+rb_f_at_exit(VALUE _)
+{
+    VALUE proc;
+
+    if (!rb_block_given_p()) {
+        rb_raise(rb_eArgError, "called without a block");
+    }
+    proc = rb_block_proc();
+    rb_set_end_proc(rb_call_end_proc, proc);
+    return proc;
+}
+
+struct end_proc_data {
+    void (*func) (VALUE);
+    VALUE data;
+    struct end_proc_data *next;
+};
+
+static struct end_proc_data *end_procs, *ephemeral_end_procs;
+
+void
+rb_set_end_proc(void (*func)(VALUE), VALUE data)
+{
+    struct end_proc_data *link = ALLOC(struct end_proc_data);
+    struct end_proc_data **list;
+    rb_thread_t *th = GET_THREAD();
+
+    if (th->top_wrapper) {
+        list = &ephemeral_end_procs;
+    }
+    else {
+        list = &end_procs;
+    }
+    link->next = *list;
+    link->func = func;
+    link->data = data;
+    *list = link;
+}
+
+void
+rb_mark_end_proc(void)
+{
+    struct end_proc_data *link;
+
+    link = end_procs;
+    while (link) {
+        rb_gc_mark(link->data);
+        link = link->next;
+    }
+    link = ephemeral_end_procs;
+    while (link) {
+        rb_gc_mark(link->data);
+        link = link->next;
+    }
+}
+
+static void
+exec_end_procs_chain(struct end_proc_data *volatile *procs, VALUE *errp)
+{
+    struct end_proc_data volatile endproc;
+    struct end_proc_data *link;
+    VALUE errinfo = *errp;
+
+    while ((link = *procs) != 0) {
+        *procs = link->next;
+        endproc = *link;
+        SIZED_FREE(link);
+        (*endproc.func) (endproc.data);
+        *errp = errinfo;
+    }
+}
+
+static void
+rb_ec_exec_end_proc(rb_execution_context_t * ec)
+{
+    enum ruby_tag_type state;
+    volatile VALUE errinfo = ec->errinfo;
+    volatile bool finished = false;
+
+    while (!finished) {
+        EC_PUSH_TAG(ec);
+        if ((state = EC_EXEC_TAG()) == TAG_NONE) {
+            exec_end_procs_chain(&ephemeral_end_procs, &ec->errinfo);
+            exec_end_procs_chain(&end_procs, &ec->errinfo);
+            finished = true;
+        }
+        EC_POP_TAG();
+        if (state != TAG_NONE) {
+            error_handle(ec, ec->errinfo, state);
+            if (!NIL_P(ec->errinfo)) errinfo = ec->errinfo;
+        }
+    }
+
+    ec->errinfo = errinfo;
+}
+
+void
+Init_jump(void)
+{
+    rb_define_global_function("at_exit", rb_f_at_exit, 0);
+}