Introduce v8::MicrotasksScope.

src/api.h

 // Copyright 2012 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.
 
 #ifndef V8_API_H_
 #define V8_API_H_
 
 #include "include/v8-testing.h"
 #include "src/contexts.h"
 #include "src/factory.h"
@@ skipping 416 matching lines @@
   DeferredHandles* next_;
   DeferredHandles* previous_;
   Object** first_block_limit_;
   Isolate* isolate_;
 
   friend class HandleScopeImplementer;
   friend class Isolate;
 };
 
 
+// Microtasks invocation policy. Keep in sync with v8::Isolate::MicrotasksPolicy
+enum MicrotasksPolicy {

[jochen (gone - plz use gerrit), 2016/03/01 14:26:08]

why not just use the public version?

[dgozman, 2016/03/03 01:22:06]

Done.

+  kExplicitMicrotasksInvocation,
+  kScopedMicrotasksInvocation,
+  kAutoMicrotasksInvocation
+};
+
+
 // This class is here in order to be able to declare it a friend of
 // HandleScope.  Moving these methods to be members of HandleScope would be
 // neat in some ways, but it would expose internal implementation details in
 // our public header file, which is undesirable.
 //
 // An isolate has a single instance of this class to hold the current thread's
 // data. In multithreaded V8 programs this data is copied in and out of storage
 // so that the currently executing thread always has its own copy of this
 // data.
 class HandleScopeImplementer {
  public:
   explicit HandleScopeImplementer(Isolate* isolate)
       : isolate_(isolate),
         blocks_(0),
         entered_contexts_(0),
         saved_contexts_(0),
         spare_(NULL),
         call_depth_(0),
+        microtasks_suppression_(0),
+#ifdef V8_ENABLE_CHECKS
+        debug_call_depth_(0),
+#endif
+        internal_call_depth_(0),
+        microtasks_policy_(kAutoMicrotasksInvocation),
         last_handle_before_deferred_block_(NULL) { }
 
   ~HandleScopeImplementer() {
     DeleteArray(spare_);
   }
 
   // Threading support for handle data.
   static int ArchiveSpacePerThread();
   char* RestoreThread(char* from);
   char* ArchiveThread(char* to);
   void FreeThreadResources();
 
   // Garbage collection support.
   void Iterate(v8::internal::ObjectVisitor* v);
   static char* Iterate(v8::internal::ObjectVisitor* v, char* data);
 
 
   inline internal::Object** GetSpareOrNewBlock();
   inline void DeleteExtensions(internal::Object** prev_limit);
 
   inline void IncrementCallDepth() {call_depth_++;}

[adamk, 2016/03/01 19:10:34]

Given the below new types of "call depth", I think this now deserves a comment
as well.

   inline void DecrementCallDepth() {call_depth_--;}
-  inline bool CallDepthIsZero() { return call_depth_ == 0; }
+  inline int GetCallDepth() { return call_depth_; }
+
+  inline void IncrementMicrotasksSuppression() {microtasks_suppression_++;}

[adamk, 2016/03/01 19:10:34]

This could use a comment, what is this counter for?

+  inline void DecrementMicrotasksSuppression() {microtasks_suppression_--;}
+  inline bool GetMicrotasksSuppression() { return microtasks_suppression_; }
+
+#ifdef V8_ENABLE_CHECKS
+  inline void IncrementDebugCallDepth() {debug_call_depth_++;}

[adamk, 2016/03/01 19:10:34]

Please add comments, what's a "debug call depth"?

+  inline void DecrementDebugCallDepth() {debug_call_depth_--;}
+  inline bool GetDebugCallDepth() { return debug_call_depth_; }
+#endif
+
+  inline void IncrementInternalCallDepth() {internal_call_depth_++;}

[adamk, 2016/03/01 19:10:34]

Same here, what's an "internal call depth"?

+  inline void DecrementInternalCallDepth() {internal_call_depth_--;}
+  inline bool GetInternalCallDepth() { return internal_call_depth_; }
+
+  inline void set_microtasks_policy(MicrotasksPolicy policy);
+  inline MicrotasksPolicy microtasks_policy() const;
 
   inline void EnterContext(Handle<Context> context);
   inline void LeaveContext();
   inline bool LastEnteredContextWas(Handle<Context> context);
 
   // Returns the last entered context or an empty handle if no
   // contexts have been entered.
   inline Handle<Context> LastEnteredContext();
 
   inline void SaveContext(Context* context);
@@ skipping 37 matching lines @@
   DeferredHandles* Detach(Object** prev_limit);
 
   Isolate* isolate_;
   List<internal::Object**> blocks_;
   // Used as a stack to keep track of entered contexts.
   List<Context*> entered_contexts_;
   // Used as a stack to keep track of saved contexts.
   List<Context*> saved_contexts_;
   Object** spare_;
   int call_depth_;
+  int microtasks_suppression_;
+#ifdef V8_ENABLE_CHECKS
+  int debug_call_depth_;
+#endif
+  int internal_call_depth_;
+  MicrotasksPolicy microtasks_policy_;
   Object** last_handle_before_deferred_block_;
   // This is only used for threading support.
   HandleScopeData handle_scope_data_;
 
   void IterateThis(ObjectVisitor* v);
   char* RestoreThreadHelper(char* from);
   char* ArchiveThreadHelper(char* to);
 
   friend class DeferredHandles;
   friend class DeferredHandleScope;
 
   DISALLOW_COPY_AND_ASSIGN(HandleScopeImplementer);
 };
 
 
 const int kHandleBlockSize = v8::internal::KB - 2;  // fit in one page
 
 
+void HandleScopeImplementer::set_microtasks_policy(MicrotasksPolicy policy) {
+  microtasks_policy_ = policy;
+}
+
+
+MicrotasksPolicy HandleScopeImplementer::microtasks_policy() const {
+  return microtasks_policy_;
+}
+
+
 void HandleScopeImplementer::SaveContext(Context* context) {
   saved_contexts_.Add(context);
 }
 
 
 Context* HandleScopeImplementer::RestoreContext() {
   return saved_contexts_.RemoveLast();
 }
 
 
@@ skipping 78 matching lines @@
   }
 
  private:
   static v8::Testing::StressType stress_type_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_API_H_