Add support for interrupting an isolate in the vm. Interrupts are

runtime/vm/isolate.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_ISOLATE_H_
 #define VM_ISOLATE_H_
 
 #include <limits.h>
 
 #include "include/dart_api.h"
 #include "vm/assert.h"
 #include "vm/store_buffer.h"
 #include "vm/timer.h"
 
 namespace dart {
 
 // Forward declarations.
 class ApiState;
 class BigintStore;
 class CodeIndexTable;
 class Debugger;
 class HandleScope;
 class Heap;
 class LongJump;
 class MessageQueue;
-class Monitor;
+class Mutex;
 class ObjectPointerVisitor;
 class ObjectStore;
 class RawContext;
 class RawObject;
 class StackResource;
 class StubCode;
 class Zone;
 
 class Isolate {
  public:
@@ skipping 175 matching lines @@
     return init_callback_data_;
   }
 
   Dart_LibraryTagHandler library_tag_handler() const {
     return library_tag_handler_;
   }
   void set_library_tag_handler(Dart_LibraryTagHandler value) {
     library_tag_handler_ = value;
   }
 
-  static void SetCreateCallback(Dart_IsolateCreateCallback cback);
-  static Dart_IsolateCreateCallback CreateCallback();
+  void SetStackLimit(uword value);
+  void SetStackLimitFromCurrentTOS(uword isolate_stack_top);
 
   uword stack_limit_address() const {
     return reinterpret_cast<uword>(&stack_limit_);
   }
 
-  void SetStackLimit(uword value);
+  // The current stack limit.  This may be overwritten with a special
+  // value to trigger interrupts.
   uword stack_limit() const { return stack_limit_; }
 
-  void SetStackLimitFromCurrentTOS(uword isolate_stack_top);
+  // The true stack limit for this isolate.  This does not change
+  // after isolate initialization.
+  uword saved_stack_limit() const { return saved_stack_limit_; }
+
+  enum {
+    kInterruptsMask = 0x1,
+    kApiInterrupt = 0x1,  // An interrupt from Dart_InterruptIsolate.
+    // More interrupt types will go here.
+  };
+
+  void ScheduleInterrupts(uword interrupt_bits);
+  uword GetAndClearInterrupts();
 
   // Returns null on success, unhandled exception on failure.
   RawObject* StandardRunLoop();
 
   intptr_t ast_node_id() const { return ast_node_id_; }
   void set_ast_node_id(int value) { ast_node_id_ = value; }
 
   Debugger* debugger() const { return debugger_; }
 
+  static void SetCreateCallback(Dart_IsolateCreateCallback cback);
+  static Dart_IsolateCreateCallback CreateCallback();
+
+  static void SetInterruptCallback(Dart_IsolateInterruptCallback cback);
+  static Dart_IsolateInterruptCallback InterruptCallback();
+
  private:
   Isolate();
 
   void PrintInvokedFunctions();
 
   static uword GetSpecifiedStackSize();
 
   static const uword kStackSizeBuffer = (128 * KB);
   static const uword kDefaultStackSize = (1 * MB);
 
   StoreBufferBlock store_buffer_;
-  Monitor* monitor_;
   MessageQueue* message_queue_;
   Dart_PostMessageCallback post_message_callback_;
   Dart_ClosePortCallback close_port_callback_;
   intptr_t num_ports_;
   intptr_t live_ports_;
   Dart_Port main_port_;
   Heap* heap_;
   ObjectStore* object_store_;
   StackResource* top_resource_;
   RawContext* top_context_;
   Zone* current_zone_;
 #if defined(DEBUG)
   int32_t no_gc_scope_depth_;
   int32_t no_handle_scope_depth_;
   HandleScope* top_handle_scope_;
 #endif
   int32_t random_seed_;
   BigintStore* bigint_store_;
   uword top_exit_frame_info_;
   void* init_callback_data_;
   Dart_LibraryTagHandler library_tag_handler_;
   ApiState* api_state_;
   StubCode* stub_code_;
   CodeIndexTable* code_index_table_;
   Debugger* debugger_;
   LongJump* long_jump_base_;
   TimerList timer_list_;
+  intptr_t ast_node_id_;
+  Mutex* mutex_;  // protects stack_limit_ and saved_stack_limit_.
   uword stack_limit_;
-  intptr_t ast_node_id_;
+  uword saved_stack_limit_;
 
   static Dart_IsolateCreateCallback create_callback_;
+  static Dart_IsolateInterruptCallback interrupt_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(Isolate);
 };
 
 }  // namespace dart
 
 #if defined(TARGET_OS_LINUX)
 #include "vm/isolate_linux.h"
 #elif defined(TARGET_OS_MACOS)
 #include "vm/isolate_macos.h"
 #elif defined(TARGET_OS_WINDOWS)
 #include "vm/isolate_win.h"
 #else
 #error Unknown target os.
 #endif
 
 #endif  // VM_ISOLATE_H_