Support this binding retrieval for backtrace frames (#4669)

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com
2021-05-17 11:41:29 +02:00
parent a67f198134
commit 67a61bc211
5 changed files with 97 additions and 8 deletions
@@ -10606,6 +10606,7 @@ main (void)
 - [jerry_backtrace_get_frame_type](#jerry_backtrace_get_frame_type)
 - [jerry_backtrace_get_location](#jerry_backtrace_get_location)
 - [jerry_backtrace_get_function](#jerry_backtrace_get_function)
+- [jerry_backtrace_get_this](#jerry_backtrace_get_this)
 - [jerry_backtrace_is_strict](#jerry_backtrace_is_strict)


@@ -10785,6 +10786,63 @@ backtrace_callback (jerry_backtrace_frame_t *frame_p,
 - [jerry_backtrace_capture](#jerry_backtrace_capture)


+## jerry_backtrace_get_this
+
+**Summary**
+
+Initialize and return with the 'this' binding private field of a backtrace frame.
+The 'this' binding is a hidden value passed to the called function. As for arrow
+functions, the 'this' binding is assigned at function creation. This getter
+function can only be called from the callback function of
+[jerry_backtrace_capture](#jerry_backtrace_capture), and the value becomes invalid
+after the callback returns.
+
+*Notes*:
+- The returned data must not be modified, and does not need to be freed.
+  Any cleanup is done automatically after the callback is returned.
+
+**Prototype**
+
+```c
+const jerry_value_t *
+jerry_backtrace_get_this (jerry_backtrace_frame_t *frame_p);
+```
+
+- `frame_p` - a frame passed to the [jerry_backtrace_callback_t](#jerry_backtrace_callback_t) callback
+- return value
+  - pointer to the 'this' binding if the binding is available,
+  - NULL otherwise
+
+*New in version [[NEXT_RELEASE]]*.
+
+**Example**
+
+See the example of [jerry_backtrace_capture](#jerry_backtrace_capture)
+with the following callback function:
+
+```c
+static bool
+backtrace_callback (jerry_backtrace_frame_t *frame_p,
+                    void *user_p)
+{
+  jerry_value_t *this_p = jerry_backtrace_get_this (frame_p);
+
+  if (this_p != NULL)
+  {
+    printf ("The 'this' binding is available");
+    return true;
+  }
+
+  printf ("The 'this' binding is NOT available");
+  return true;
+}
+```
+
+**See also**
+
+- [jerry_backtrace_capture](#jerry_backtrace_capture)
+
+
 ## jerry_backtrace_is_strict

 **Summary**