Added a run state field to Isolate

runtime/vm/isolate.h

Index: runtime/vm/isolate.h
===================================================================
--- runtime/vm/isolate.h	(revision 21380)
+++ runtime/vm/isolate.h	(working copy)
@@ -273,6 +273,11 @@
         kVmStatusInterrupt,
   };
 
+  enum {

[Ivan Posva, 2013/04/12 21:23:03]

Please name this enum.

[Tom Ball, 2013/04/12 21:56:47]

Done.

+    kIsolateWaiting = 0x1,       // The isolate is waiting for code to execute.

[Ivan Posva, 2013/04/12 21:23:03]

= 0

[Tom Ball, 2013/04/12 21:56:47]

Done.

+    kIsolateRunning = 0x2,       // The isolate is executing code.

[Ivan Posva, 2013/04/12 21:23:03]

We do not necessarily care about this absolute value, so just let it sit empty.

[Tom Ball, 2013/04/12 21:56:47]

Done.

+  };
+
   void ScheduleInterrupts(uword interrupt_bits);
   uword GetAndClearInterrupts();
 
@@ -285,6 +290,9 @@
   bool is_runnable() const { return is_runnable_; }
   void set_is_runnable(bool value) { is_runnable_ = value; }
 
+  uword running_state() const { return running_state_; }

[Ivan Posva, 2013/04/12 21:23:03]

Once the enum is name we do not have to pass uwords for the state.

[Tom Ball, 2013/04/12 21:56:47]

Done.

+  void set_running_state(uword value) { running_state_ = value; }
+
   uword spawn_data() const { return spawn_data_; }
   void set_spawn_data(uword value) { spawn_data_ = value; }
 
@@ -492,6 +500,7 @@
   MessageHandler* message_handler_;
   uword spawn_data_;
   bool is_runnable_;

[Ivan Posva, 2013/04/12 21:23:03]

What is the difference to this field? Shouldn't they be combined?

[Tom Ball, 2013/04/12 21:56:47]

I found that a client can invoke multiple functions in a single isolate, so I
thought it clearer for runnable to mean that it is valid to invoke a function in
an isolate, and run_state_ to indicate whether it's currently executing a
function. I can combine the two fields if you'd rather, though.

+  uword running_state_;
   GcPrologueCallbacks gc_prologue_callbacks_;
   GcEpilogueCallbacks gc_epilogue_callbacks_;
 
@@ -607,6 +616,28 @@
   char* exception_callback_name_;
 };
 
+
+class IsolateRunStateManager : public StackResource {
+ public:
+  explicit IsolateRunStateManager()
+      : StackResource(Isolate::Current()), saved_state_(0) {
+    saved_state_ = reinterpret_cast<Isolate*>(isolate())->running_state();
+  }
+
+  virtual ~IsolateRunStateManager() {
+    reinterpret_cast<Isolate*>(isolate())->set_running_state(saved_state_);
+  }
+
+  void SetRunState(uword run_state) {
+    reinterpret_cast<Isolate*>(isolate())->set_running_state(run_state);
+  }
+
+ private:
+  uword saved_state_;
+
+  DISALLOW_COPY_AND_ASSIGN(IsolateRunStateManager);
+};
+
 }  // namespace dart
 
 #endif  // VM_ISOLATE_H_