Support 'restart call frame' debug command

src/liveedit.cc

Index: src/liveedit.cc
diff --git a/src/liveedit.cc b/src/liveedit.cc
index e670b442b6d5033c4734d307a3cc74c9d094d537..47208f660c54f93e4aff452ff118d0a492e66f8f 100644
--- a/src/liveedit.cc
+++ b/src/liveedit.cc
@@ -1595,17 +1595,36 @@ 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 execute any of listed functions.
+// Finding no such frames does not mean error.
+class MultipleFunctionTarget {
+ public:
+  MultipleFunctionTarget(Handle<JSArray> shared_info_array,
+      Handle<JSArray> result)
+      : m_shared_info_array(shared_info_array),
+        m_result(result) {}
+  bool MatchActivation(StackFrame* frame,
+      LiveEdit::FunctionPatchabilityStatus status) {
+    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;
@@ -1615,8 +1634,8 @@ static const char* DropActivationsInActiveThread(
       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)) {
       // 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";
@@ -1625,7 +1644,7 @@ static const char* DropActivationsInActiveThread(
 
   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;
@@ -1638,8 +1657,8 @@ static const char* DropActivationsInActiveThread(
       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)) {
       target_frame_found = true;
       bottom_js_frame_index = frame_index;
     }
@@ -1651,8 +1670,8 @@ static const char* DropActivationsInActiveThread(
     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)) {
           // Cannot drop frame under C frames.
           return NULL;
         }
@@ -1667,7 +1686,7 @@ static const char* DropActivationsInActiveThread(
 
   if (!target_frame_found) {
     // Nothing to drop.
-    return NULL;
+    return target.GetNotFoundMessage();
   }
 
   Debug::FrameDropMode drop_mode = Debug::FRAMES_UNTOUCHED;
@@ -1690,6 +1709,23 @@ static const char* DropActivationsInActiveThread(
   }
   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);
+  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++) {
@@ -1766,6 +1802,41 @@ Handle<JSArray> LiveEdit::CheckAndDropActivations(
 }
 
 
+// Describes a single callframe a target. Not finding this frame
+// means an error.
+class SingleFrameTarget {
+ public:
+  explicit SingleFrameTarget(JavaScriptFrame* frame) : m_frame(frame) {}
+
+  bool MatchActivation(StackFrame* frame,
+      LiveEdit::FunctionPatchabilityStatus status) {
+    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) {