Introduce API to temporarily interrupt long running JavaScript code.

src/execution.cc

 // Copyright 2012 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 522 matching lines @@
 
 void StackGuard::Continue(InterruptFlag after_what) {
   ExecutionAccess access(isolate_);
   thread_local_.interrupt_flags_ &= ~static_cast<int>(after_what);
   if (!should_postpone_interrupts(access) && !has_pending_interrupts(access)) {
     reset_limits(access);
   }
 }
 
 
+void StackGuard::RequestInterrupt(InterruptCallback callback, void* data) {
+  ExecutionAccess access(isolate_);
+  thread_local_.interrupt_flags_ |= API_INTERRUPT;
+  thread_local_.interrupt_callback_ = callback;
+  thread_local_.interrupt_callback_data_ = data;
+  set_interrupt_limits(access);
+}
+
+
+void StackGuard::ClearInterrupt() {
+  thread_local_.interrupt_callback_ = 0;
+  thread_local_.interrupt_callback_data_ = 0;
+  Continue(API_INTERRUPT);
+}
+
+
+bool StackGuard::IsAPIInterrupt() {
+  ExecutionAccess access(isolate_);
+  return thread_local_.interrupt_flags_ & API_INTERRUPT;
+}
+
+
+void StackGuard::InvokeInterruptCallback() {
+  InterruptCallback callback = 0;
+  void* data = 0;
+
+  {
+    ExecutionAccess access(isolate_);
+    callback = thread_local_.interrupt_callback_;
+    data = thread_local_.interrupt_callback_data_;
+    thread_local_.interrupt_callback_ = NULL;
+    thread_local_.interrupt_callback_data_ = NULL;
+  }
+
+  if (callback != NULL) {
+    VMState<EXTERNAL> state(isolate_);
+    HandleScope handle_scope(isolate_);
+    callback(reinterpret_cast<v8::Isolate*>(isolate_), data);
+  }
+}
+
+
 char* StackGuard::ArchiveStackGuard(char* to) {
   ExecutionAccess access(isolate_);
   OS::MemCopy(to, reinterpret_cast<char*>(&thread_local_), sizeof(ThreadLocal));
   ThreadLocal blank;
 
   // Set the stack limits using the old thread_local_.
   // TODO(isolates): This was the old semantics of constructing a ThreadLocal
   //                 (as the ctor called SetStackLimits, which looked at the
   //                 current thread_local_ from StackGuard)-- but is this
   //                 really what was intended?
@@ skipping 21 matching lines @@
 
 
 void StackGuard::ThreadLocal::Clear() {
   real_jslimit_ = kIllegalLimit;
   jslimit_ = kIllegalLimit;
   real_climit_ = kIllegalLimit;
   climit_ = kIllegalLimit;
   nesting_ = 0;
   postpone_interrupts_nesting_ = 0;
   interrupt_flags_ = 0;
+  interrupt_callback_ = 0;
 }
 
 
 bool StackGuard::ThreadLocal::Initialize(Isolate* isolate) {
   bool should_set_stack_limits = false;
   if (real_climit_ == kIllegalLimit) {
     // Takes the address of the limit variable in order to find out where
     // the top of stack is right now.
     const uintptr_t kLimitSize = FLAG_stack_size * KB;
     uintptr_t limit = reinterpret_cast<uintptr_t>(&limit) - kLimitSize;
     ASSERT(reinterpret_cast<uintptr_t>(&limit) > kLimitSize);
     real_jslimit_ = SimulatorStack::JsLimitFromCLimit(isolate, limit);
     jslimit_ = SimulatorStack::JsLimitFromCLimit(isolate, limit);
     real_climit_ = limit;
     climit_ = limit;
     should_set_stack_limits = true;
   }
   nesting_ = 0;
   postpone_interrupts_nesting_ = 0;
   interrupt_flags_ = 0;
+  interrupt_callback_ = 0;
   return should_set_stack_limits;
 }
 
 
 void StackGuard::ClearThread(const ExecutionAccess& lock) {
   thread_local_.Clear();
   isolate_->heap()->SetStackLimits();
 }
 
 
@@ skipping 315 matching lines @@
 
 
 #endif
 
 MaybeObject* Execution::HandleStackGuardInterrupt(Isolate* isolate) {
   StackGuard* stack_guard = isolate->stack_guard();
   if (stack_guard->ShouldPostponeInterrupts()) {
     return isolate->heap()->undefined_value();
   }
 
+  if (stack_guard->IsAPIInterrupt()) {
+    stack_guard->InvokeInterruptCallback();
+    stack_guard->Continue(API_INTERRUPT);
+  }
+
   if (stack_guard->IsGCRequest()) {
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "StackGuard GC request");
     stack_guard->Continue(GC_REQUEST);
   }
 
   isolate->counters()->stack_interrupts()->Increment();
   isolate->counters()->runtime_profiler_ticks()->Increment();
 #ifdef ENABLE_DEBUGGER_SUPPORT
   if (stack_guard->IsDebugBreak() || stack_guard->IsDebugCommand()) {
@@ skipping 17 matching lines @@
     ASSERT(isolate->concurrent_recompilation_enabled());
     stack_guard->Continue(INSTALL_CODE);
     isolate->optimizing_compiler_thread()->InstallOptimizedFunctions();
   }
   isolate->runtime_profiler()->OptimizeNow();
   return isolate->heap()->undefined_value();
 }
 
 
 } }  // namespace v8::internal