Introduce API to temporarily interrupt long running JavaScript code.

src/execution.h

 // Copyright 2011 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 25 matching lines @@
 
 // Flag used to set the interrupt causes.
 enum InterruptFlag {
   INTERRUPT = 1 << 0,
   DEBUGBREAK = 1 << 1,
   DEBUGCOMMAND = 1 << 2,
   PREEMPT = 1 << 3,
   TERMINATE = 1 << 4,
   GC_REQUEST = 1 << 5,
   FULL_DEOPT = 1 << 6,
-  INSTALL_CODE = 1 << 7
+  INSTALL_CODE = 1 << 7,
+  API_INTERRUPT = 1 << 8
 };
 
 
 class Isolate;
 
 
 class Execution : public AllStatic {
  public:
   // Call a function, the caller supplies a receiver and an array
   // of arguments. Arguments are Object* type. After function returns,
@@ skipping 158 matching lines @@
   void DebugCommand();
 #endif
   bool IsGCRequest();
   void RequestGC();
   bool IsInstallCodeRequest();
   void RequestInstallCode();
   bool IsFullDeopt();
   void FullDeopt();
   void Continue(InterruptFlag after_what);
 
+  void RequestInterrupt(InterruptCallback callback, void* data);
+  void ClearInterrupt();
+  bool IsAPIInterrupt();
+  void InvokeInterruptCallback();
+
   // This provides an asynchronous read of the stack limits for the current
   // thread.  There are no locks protecting this, but it is assumed that you
   // have the global V8 lock if you are using multiple V8 threads.
   uintptr_t climit() {
     return thread_local_.climit_;
   }
   uintptr_t real_climit() {
     return thread_local_.real_climit_;
   }
   uintptr_t jslimit() {
@@ skipping 65 matching lines @@
     // fail. Both the generated code and the runtime system check against the
     // one without the real_ prefix.
     uintptr_t real_jslimit_;  // Actual JavaScript stack limit set for the VM.
     uintptr_t jslimit_;
     uintptr_t real_climit_;  // Actual C++ stack limit set for the VM.
     uintptr_t climit_;
 
     int nesting_;
     int postpone_interrupts_nesting_;
     int interrupt_flags_;
+
+    InterruptCallback interrupt_callback_;
+    void* interrupt_callback_data_;
   };
 
   // TODO(isolates): Technically this could be calculated directly from a
   //                 pointer to StackGuard.
   Isolate* isolate_;
   ThreadLocal thread_local_;
 
   friend class Isolate;
   friend class StackLimitCheck;
   friend class PostponeInterruptsScope;
 
   DISALLOW_COPY_AND_ASSIGN(StackGuard);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_EXECUTION_H_