Merge pull request #5362 from dearblue/binding

Binding

1 files changed, 72 insertions, 7 deletions

diff --git a/src/vm.c b/src/vm.c
index 0e7eb65e5..2607ba308 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -483,13 +483,73 @@ mrb_funcall_argv(mrb_state *mrb, mrb_value self, mrb_sym mid, mrb_int argc, cons
   return mrb_funcall_with_block(mrb, self, mid, argc, argv, mrb_nil_value());
 }
 
+#define DECOMPOSE32(n) (((n) >> 24) & 0xff), (((n) >> 16) & 0xff), (((n) >> 8) & 0xff), (((n) >> 0) & 0xff)
+#define CATCH_HANDLER_MAKE_BYTECODE(t, b, e, j) t, DECOMPOSE32(b), DECOMPOSE32(e), DECOMPOSE32(j)
+#define CATCH_HANDLER_NUM_TO_BYTE(n) ((n) * sizeof(struct mrb_irep_catch_handler))
+
+static void
+mrb_exec_irep_prepare_posthook(mrb_state *mrb, mrb_callinfo *ci, int nregs, mrb_func_t posthook)
+{
+  /*
+   *  stack: [proc, errinfo, return value by called proc]
+   *
+   *  begin
+   *    OP_NOP        # A dummy instruction built in to make the catch handler react.
+   *  ensure
+   *    OP_EXCEPT R1  # Save the exception object.
+   *    OP_CALL       # Call a C function for the hook.
+   *                  # The stack is kept as it is in the called proc.
+   *                  # The exception will be rethrown within the hook function.
+   *  end
+   */
+  static const mrb_code hook_iseq[] = {
+    OP_NOP,
+    OP_EXCEPT, 1,
+    OP_CALL,
+    CATCH_HANDLER_MAKE_BYTECODE(MRB_CATCH_ENSURE, 0, 1, 1),
+  };
+  static const mrb_irep hook_irep = {
+    1, 3, 1, MRB_IREP_STATIC, hook_iseq,
+    NULL, NULL, NULL, NULL, NULL,
+    sizeof(hook_iseq) / sizeof(hook_iseq[0]) - CATCH_HANDLER_NUM_TO_BYTE(1),
+    0, 0, 0, 0
+  };
+  static const struct RProc hook_caller = {
+    NULL, NULL, MRB_TT_PROC, 7 /* GC_RED */, MRB_FL_OBJ_IS_FROZEN, { &hook_irep }, NULL, { NULL }
+  };
+
+  struct RProc *hook = mrb_proc_new_cfunc(mrb, posthook);
+  int acc = 2;
+  memmove(ci->stack + acc, ci->stack, sizeof(mrb_value) * nregs);
+  ci->stack[0] = mrb_obj_value(hook);
+  ci->stack[1] = mrb_nil_value();
+  mrb_callinfo hook_ci = { 0, 0, ci->acc, &hook_caller, ci->stack, &hook_iseq[1], { NULL } };
+  ci = cipush(mrb, acc, acc, NULL, ci[0].proc, ci[0].mid, ci[0].argc);
+  ci->u.env = ci[-1].u.env;
+  ci[-1] = hook_ci;
+}
+
+/*
+ * If `posthook` is given, `posthook` will be called even if an
+ * exception or global jump occurs in `p`. Exception or global jump objects
+ * are stored in `mrb->c->stack[1]` and should be rethrown in `posthook`.
+ *
+ *    if (!mrb_nil_p(mrb->c->stack[1])) {
+ *      mrb_exc_raise(mrb, mrb->c->stack[1]);
+ *    }
+ *
+ * If you want to return the return value by `proc` as it is, please do
+ * `return mrb->c->stack[2]`.
+ *
+ * However, if `proc` is a C function, it will be ignored.
+ */
 mrb_value
-mrb_exec_irep(mrb_state *mrb, mrb_value self, struct RProc *p)
+mrb_exec_irep(mrb_state *mrb, mrb_value self, struct RProc *p, mrb_func_t posthook)
 {
   mrb_callinfo *ci = mrb->c->ci;
   mrb_int keep, nregs;
 
-  mrb->c->ci->stack[0] = self;
+  ci->stack[0] = self;
   mrb_vm_ci_proc_set(ci, p);
   if (MRB_PROC_CFUNC_P(p)) {
     return MRB_PROC_CFUNC(p)(mrb, self);
@@ -497,12 +557,17 @@ mrb_exec_irep(mrb_state *mrb, mrb_value self, struct RProc *p)
   nregs = p->body.irep->nregs;
   if (ci->argc < 0) keep = 3;
   else keep = ci->argc + 2;
+  int extra = posthook ? (2 /* hook proc + errinfo */) : 0;
   if (nregs < keep) {
-    mrb_stack_extend(mrb, keep);
+    mrb_stack_extend(mrb, keep + extra);
   }
   else {
-    mrb_stack_extend(mrb, nregs);
-    stack_clear(mrb->c->ci->stack+keep, nregs-keep);
+    mrb_stack_extend(mrb, nregs + extra);
+    stack_clear(ci->stack+keep, nregs-keep + extra);
+  }
+
+  if (posthook) {
+    mrb_exec_irep_prepare_posthook(mrb, ci, (nregs < keep ? keep : nregs), posthook);
   }
 
   cipush(mrb, 0, 0, NULL, NULL, 0, 0);
@@ -573,7 +638,7 @@ mrb_f_send(mrb_state *mrb, mrb_value self)
     }
     return MRB_METHOD_CFUNC(m)(mrb, self);
   }
-  return mrb_exec_irep(mrb, self, MRB_METHOD_PROC(m));
+  return mrb_exec_irep(mrb, self, MRB_METHOD_PROC(m), NULL);
 }
 
 static mrb_value
@@ -760,7 +825,7 @@ mrb_yield_cont(mrb_state *mrb, mrb_value b, mrb_value self, mrb_int argc, const
   mrb->c->ci->stack[1] = mrb_ary_new_from_values(mrb, argc, argv);
   mrb->c->ci->stack[2] = mrb_nil_value();
   ci->argc = -1;
-  return mrb_exec_irep(mrb, self, p);
+  return mrb_exec_irep(mrb, self, p, NULL);
 }
 
 static struct RBreak*