Make number of available threads isolate-dependent and expose it to ResourceConstraints.

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index f0b627e7b79c16c05f5c64beedb572587889291e..3385c6a21eb5f996d8388063ef21fee352d970a0 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -3822,12 +3822,17 @@ class V8_EXPORT ResourceConstraints {
   uint32_t* stack_limit() const { return stack_limit_; }
   // Sets an address beyond which the VM's stack may not grow.
   void set_stack_limit(uint32_t* value) { stack_limit_ = value; }
+  int max_available_threads() { return max_available_threads_; }

[Sven Panne, 2013/11/18 14:40:07]

const

Furthermore, the semantics and the typing are slightly confusing: What the
getter returns is actually a Maybe<int>, but even then it is not clear what e.g.
1 means: Does it mean no concurrency at all or 1 additional thread apart from
the main JavaScript thread? I guess it's the former, but this is a bit unclear.
Either add a comment or choose a better name.

The "Maybe" part holds for all the other fields of this POD, too, but it's
already baked into our current API. :-( I propose to leave everything as it is
and get the typing right when the constraints become part of the Isolate's
constructor arguments.

+  void set_max_available_threads(int value) {
+    max_available_threads_ = value;
+  }
 
  private:
   int max_young_space_size_;
   int max_old_space_size_;
   int max_executable_size_;
   uint32_t* stack_limit_;
+  int max_available_threads_;
 };