Allow debugger to step into Map and Set forEach callbacks

test/mjsunit/harmony/debug-stepin-collections-foreach.js

Index: test/mjsunit/harmony/debug-stepin-collections-foreach.js
diff --git a/test/mjsunit/harmony/debug-stepin-collections-foreach.js b/test/mjsunit/harmony/debug-stepin-collections-foreach.js
new file mode 100644
index 0000000000000000000000000000000000000000..30fa8c00492667d2ec404da87c0f39a10120d5b0
--- /dev/null
+++ b/test/mjsunit/harmony/debug-stepin-collections-foreach.js
@@ -0,0 +1,118 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// Flags: --expose-debug-as debug --harmony-collections
+
+Debug = debug.Debug
+
+var exception = false;
+
+function listener(event, exec_state, event_data, data) {
+  try {
+    if (event == Debug.DebugEvent.Break) {
+      if (breaks == 0) {
+        exec_state.prepareStep(Debug.StepAction.StepIn, 2);
+        breaks = 1;
+      } else if (breaks <= 3) {
+        breaks++;
+        // Check whether we break at the expected line.
+        print(event_data.sourceLineText());
+        assertTrue(event_data.sourceLineText().indexOf("Expected to step") > 0);
+        exec_state.prepareStep(Debug.StepAction.StepIn, 3);
+      }
+    }
+  } catch (e) {
+    exception = true;
+  }
+}
+
+function cb_set(num) {
+  print("element " + num);  // Expected to step to this point.
+  return true;
+}
+
+function cb_map(key, val) {
+  print("key " + key + ", value " + val);  // Expected to step to this point.
+  return true;
+}
+
+var s = new Set();
+s.add(1);
+s.add(2);
+s.add(3);
+s.add(4);
+
+var m = new Map();
+m.set('foo', 1);
+m.set('bar', 2);
+m.set('baz', 3);
+m.set('bat', 4);
+
+Debug.setListener(listener);
+
+var breaks = 0;
+debugger;
+s.forEach(cb_set);
+assertFalse(exception);
+assertEquals(4, breaks);
+
+breaks = 0;
+debugger;
+m.forEach(cb_map);
+assertFalse(exception);
+assertEquals(4, breaks);
+
+Debug.setListener(null);
+
+
+// Test two levels of builtin callbacks:
+// Array.forEach calls a callback function, which by itself uses
+// Array.forEach with another callback function.
+
+function second_level_listener(event, exec_state, event_data, data) {
+  try {
+    if (event == Debug.DebugEvent.Break) {
+      if (breaks == 0) {
+        exec_state.prepareStep(Debug.StepAction.StepIn, 3);
+        breaks = 1;
+      } else if (breaks <= 16) {
+        breaks++;
+        // Check whether we break at the expected line.
+        assertTrue(event_data.sourceLineText().indexOf("Expected to step") > 0);
+        // Step two steps further every four breaks to skip the
+        // forEach call in the first level of recurision.
+        var step = (breaks % 4 == 1) ? 6 : 3;
+        exec_state.prepareStep(Debug.StepAction.StepIn, step);
+      }
+    }
+  } catch (e) {
+    exception = true;
+  }
+}
+
+function cb_set_foreach(num) {
+  s.forEach(cb_set);
+  print("back to the first level of recursion.");
+}
+
+function cb_map_foreach(key, val) {
+  m.forEach(cb_set);
+  print("back to the first level of recursion.");
+}
+
+Debug.setListener(second_level_listener);
+
+breaks = 0;
+debugger;
+s.forEach(cb_set_foreach);
+assertFalse(exception);
+assertEquals(17, breaks);
+
+breaks = 0;
+debugger;
+m.forEach(cb_map_foreach);
+assertFalse(exception);
+assertEquals(17, breaks);
+
+Debug.setListener(null);