Support 'restart call frame' debug command

src/liveedit.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1577 matching lines @@
   }
 
   return NULL;
 }
 
 
 static bool IsDropableFrame(StackFrame* frame) {
   return !frame->is_exit();
 }
 
-// Fills result array with statuses of functions. Modifies the stack
-// removing all listed function if possible and if do_drop is true.
-static const char* DropActivationsInActiveThread(
-    Handle<JSArray> shared_info_array, Handle<JSArray> result, bool do_drop,
-    Zone* zone) {
+
+// Describes a set of call frames that executes any of listed functions.
+// Finding no such frames does not mean error.
+class MultipleFunctionTarget {
+ public:
+  MultipleFunctionTarget(Handle<JSArray> shared_info_array, Handle<JSArray> result)

[Yang, 2012/06/14 09:09:28]

80 char limit.

[Peter Rybin, 2012/06/14 22:08:03]

Done.

+      : m_shared_info_array(shared_info_array),
+        m_result(result)
+  {
+  }

[Yang, 2012/06/14 09:09:28]

You can put the empty function body on the same line as the last item in the
initialization list.

[Peter Rybin, 2012/06/14 22:08:03]

Done.

+  bool MatchActivation(StackFrame* frame, LiveEdit::FunctionPatchabilityStatus status) {

[Yang, 2012/06/14 09:09:28]

80 char limit.

[Peter Rybin, 2012/06/14 22:08:03]

Done.

+    return CheckActivation(m_shared_info_array, m_result, frame, status);
+  }
+  const char* GetNotFoundMessage() {
+    return NULL;
+  }
+ private:
+  Handle<JSArray> m_shared_info_array;
+  Handle<JSArray> m_result;
+};
+
+// Drops all call frame matched by target and all frames above them.
+template<typename TARGET>
+static const char* DropActivationsInActiveThreadImpl(
+    TARGET& target, bool do_drop, Zone* zone) {
   Isolate* isolate = Isolate::Current();
   Debug* debug = isolate->debug();
   ZoneScope scope(isolate, DELETE_ON_EXIT);
   Vector<StackFrame*> frames = CreateStackMap(zone);
 
-  int array_len = Smi::cast(shared_info_array->length())->value();
 
   int top_frame_index = -1;
   int frame_index = 0;
   for (; frame_index < frames.length(); frame_index++) {
     StackFrame* frame = frames[frame_index];
     if (frame->id() == debug->break_frame_id()) {
       top_frame_index = frame_index;
       break;
     }
-    if (CheckActivation(shared_info_array, result, frame,
-                        LiveEdit::FUNCTION_BLOCKED_UNDER_NATIVE_CODE)) {
+    if (target.MatchActivation(
+        frame, LiveEdit::FUNCTION_BLOCKED_UNDER_NATIVE_CODE)) {

[Yang, 2012/06/14 09:09:28]

4 spaces more indent.

[Peter Rybin, 2012/06/14 22:08:03]

Done.

       // We are still above break_frame. It is not a target frame,
       // it is a problem.
       return "Debugger mark-up on stack is not found";
     }
   }
 
   if (top_frame_index == -1) {
     // We haven't found break frame, but no function is blocking us anyway.
-    return NULL;
+    return target.GetNotFoundMessage();
   }
 
   bool target_frame_found = false;
   int bottom_js_frame_index = top_frame_index;
   bool c_code_found = false;
 
   for (; frame_index < frames.length(); frame_index++) {
     StackFrame* frame = frames[frame_index];
     if (!IsDropableFrame(frame)) {
       c_code_found = true;
       break;
     }
-    if (CheckActivation(shared_info_array, result, frame,
-                        LiveEdit::FUNCTION_BLOCKED_ON_ACTIVE_STACK)) {
+    if (target.MatchActivation(
+        frame, LiveEdit::FUNCTION_BLOCKED_ON_ACTIVE_STACK)) {

[Yang, 2012/06/14 09:09:28]

ditto.

[Peter Rybin, 2012/06/14 22:08:03]

Done.

       target_frame_found = true;
       bottom_js_frame_index = frame_index;
     }
   }
 
   if (c_code_found) {
     // There is a C frames on stack. Check that there are no target frames
     // below them.
     for (; frame_index < frames.length(); frame_index++) {
       StackFrame* frame = frames[frame_index];
       if (frame->is_java_script()) {
-        if (CheckActivation(shared_info_array, result, frame,
-                            LiveEdit::FUNCTION_BLOCKED_UNDER_NATIVE_CODE)) {
+        if (target.MatchActivation(
+            frame, LiveEdit::FUNCTION_BLOCKED_UNDER_NATIVE_CODE)) {

[Yang, 2012/06/14 09:09:28]

ditto.

[Peter Rybin, 2012/06/14 22:08:03]

Done.

           // Cannot drop frame under C frames.
           return NULL;
         }
       }
     }
   }
 
   if (!do_drop) {
     // We are in check-only mode.
     return NULL;
   }
 
   if (!target_frame_found) {
     // Nothing to drop.
-    return NULL;
+    return target.GetNotFoundMessage();
   }
 
   Debug::FrameDropMode drop_mode = Debug::FRAMES_UNTOUCHED;
   Object** restarter_frame_function_pointer = NULL;
   const char* error_message = DropFrames(frames, top_frame_index,
                                          bottom_js_frame_index, &drop_mode,
                                          &restarter_frame_function_pointer);
 
   if (error_message != NULL) {
     return error_message;
   }
 
   // Adjust break_frame after some frames has been dropped.
   StackFrame::Id new_id = StackFrame::NO_ID;
   for (int i = bottom_js_frame_index + 1; i < frames.length(); i++) {
     if (frames[i]->type() == StackFrame::JAVA_SCRIPT) {
       new_id = frames[i]->id();
       break;
     }
   }
   debug->FramesHaveBeenDropped(new_id, drop_mode,
                                restarter_frame_function_pointer);
+  return NULL;
+}
+
+// Fills result array with statuses of functions. Modifies the stack
+// removing all listed function if possible and if do_drop is true.
+static const char* DropActivationsInActiveThread(
+    Handle<JSArray> shared_info_array, Handle<JSArray> result, bool do_drop,
+    Zone* zone) {
+  MultipleFunctionTarget target(shared_info_array, result);
+
+  const char* message = DropActivationsInActiveThreadImpl(target, do_drop, zone);

[Yang, 2012/06/14 09:09:28]

80 char limit.

[Peter Rybin, 2012/06/14 22:08:03]

Done.

+  if (message) {
+    return message;
+  }
+
+  int array_len = Smi::cast(shared_info_array->length())->value();
 
   // Replace "blocked on active" with "replaced on active" status.
   for (int i = 0; i < array_len; i++) {
     if (result->GetElement(i) ==
         Smi::FromInt(LiveEdit::FUNCTION_BLOCKED_ON_ACTIVE_STACK)) {
       Handle<Object> replaced(
           Smi::FromInt(LiveEdit::FUNCTION_REPLACED_ON_ACTIVE_STACK));
       SetElementNonStrict(result, i, replaced);
     }
   }
@@ skipping 56 matching lines @@
   if (error_message != NULL) {
     // Add error message as an array extra element.
     Vector<const char> vector_message(error_message, StrLength(error_message));
     Handle<String> str = FACTORY->NewStringFromAscii(vector_message);
     SetElementNonStrict(result, len, str);
   }
   return result;
 }
 
 
+// Describes a single callframe a target. Not finding this frame
+// means an error.
+class SingleFrameTarget {
+ public:
+  SingleFrameTarget(JavaScriptFrame* frame) : m_frame(frame) {}
+
+  bool MatchActivation(StackFrame* frame, LiveEdit::FunctionPatchabilityStatus status) {

[Yang, 2012/06/14 09:09:28]

80 char limit.

[Peter Rybin, 2012/06/14 22:08:03]

Done.

+    if (frame->fp() == m_frame->fp()) {
+      m_saved_status = status;
+      return true;
+    }
+    return false;
+  }
+  const char* GetNotFoundMessage() {
+    return "Failed to found requested frame";
+  }
+  LiveEdit::FunctionPatchabilityStatus saved_status() {
+    return m_saved_status;
+  }
+ private:
+  JavaScriptFrame* m_frame;
+  LiveEdit::FunctionPatchabilityStatus m_saved_status;
+};
+
+
+// Finds a drops required frame and all frames above.
+// Returns error message or NULL.
+const char* LiveEdit::RestartFrame(JavaScriptFrame* frame, Zone* zone) {
+  SingleFrameTarget target(frame);
+
+  return DropActivationsInActiveThreadImpl(target, true, zone);
+}
+
+
 LiveEditFunctionTracker::LiveEditFunctionTracker(Isolate* isolate,
                                                  FunctionLiteral* fun)
     : isolate_(isolate) {
   if (isolate_->active_function_info_listener() != NULL) {
     isolate_->active_function_info_listener()->FunctionStarted(fun);
   }
 }
 
 
 LiveEditFunctionTracker::~LiveEditFunctionTracker() {
@@ skipping 47 matching lines @@
 
 bool LiveEditFunctionTracker::IsActive(Isolate* isolate) {
   return false;
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 
 
 } }  // namespace v8::internal