src/v8/test/debugger/debug/debug-return-value.js

// Copyright 2010 the V8 project authors. All rights reserved.
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// modification, are permitted provided that the following conditions are
// met:
//
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//       with the distribution.
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Debug = debug.Debug

listener_complete = false;
exception = false;
break_count = 0;
expected_return_value = 0;
expected_source_position = [];
debugger_source_position = 0;

// Listener which expects to do four steps to reach returning from the function.
function listener(event, exec_state, event_data, data) {
  try {
    if (event == Debug.DebugEvent.Break)
    {
      break_count++;
      if (break_count < 4) {
        switch (break_count) {
          case 1:
            // Collect the position of the debugger statement.
            debugger_source_position = exec_state.frame(0).sourcePosition();
            break;
          case 2:
            // Position now at the if statement.
            assertEquals(expected_source_position.shift() + debugger_source_position,
                         exec_state.frame(0).sourcePosition());
            break;
          case 3:
            // Position now at either of the returns.
            assertEquals(expected_source_position.shift() + debugger_source_position,
                         exec_state.frame(0).sourcePosition());
            break;
          default:
            fail("Unexpected");
        }
        exec_state.prepareStep(Debug.StepAction.StepIn);
      } else {
        // Position at the end of the function.
        assertEquals(expected_source_position.shift() + debugger_source_position,
                     exec_state.frame(0).sourcePosition());
        // Just about to return from the function.
        assertEquals(expected_return_value,
                     exec_state.frame(0).returnValue().value());

        listener_complete = true;
      }
    }
  } catch (e) {
    exception = e
    print(e + e.stack)
  };
};

// Add the debug event listener.
Debug.setListener(listener);

// Four steps from the debugger statement in this function will position us at
// the function return.
//             0         1         2         3         4         5
//             0123456789012345678901234567890123456789012345678901

function f(x) {debugger; if (x) { return 1; } else { return 2; } };

// Call f expecting different return values.
break_count = 0;
expected_return_value = 2;
expected_source_position = [10, 38, 47];
listener_complete = false;
f();
assertFalse(exception, "exception in listener")
assertTrue(listener_complete);
assertEquals(4, break_count);

break_count = 0;
expected_return_value = 1;
expected_source_position = [10, 19, 28];
listener_complete = false;
f(true);
assertFalse(exception, "exception in listener")
assertTrue(listener_complete);
assertEquals(4, break_count);

break_count = 0;
expected_return_value = 2;
expected_source_position = [10, 38, 47];
listener_complete = false;
f(false);
assertFalse(exception, "exception in listener")
assertTrue(listener_complete);
assertEquals(4, break_count);