text: // Copyright Fedor Indutny and other Node contributors.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a
  // copy of this software and associated documentation files (the
  // "Software"), to deal in the Software without restriction, including
  // without limitation the rights to use, copy, modify, merge, publish,
  // distribute, sublicense, and/or sell copies of the Software, and to permit
  // persons to whom the Software is furnished to do so, subject to the
  // following conditions:
  //
  // The above copyright notice and this permission notice shall be included
  // in all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
  // NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
  // DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  // USE OR OTHER DEALINGS IN THE SOFTWARE.
  
  #ifndef SRC_NODE_V8_PLATFORM_H_
  #define SRC_NODE_V8_PLATFORM_H_
  
  #include "uv.h"
  #include "v8-platform.h"
  
  namespace node {
  
  class TaskQueue {
   public:
    TaskQueue();
    ~TaskQueue();
  
    void Push(v8::Task* task);
    v8::Task* Shift();
  
   private:
    static unsigned int next(unsigned int n);
    bool can_read() const;
    bool can_write() const;
    uv_cond_t read_cond_;
    uv_cond_t write_cond_;
    uv_mutex_t mutex_;
    unsigned int read_off_;
    unsigned int write_off_;
    v8::Task* ring_[1024];
  };
  
  class Platform : public v8::Platform {
   public:
    explicit Platform(unsigned int worker_count);
    virtual ~Platform() override;
  
    void CallOnBackgroundThread(v8::Task* task,
                                ExpectedRuntime expected_runtime);
    void CallOnForegroundThread(v8::Isolate* isolate, v8::Task* task);
  
   protected:
    static void WorkerBody(void* arg);
  
    inline TaskQueue* global_queue() { return &global_queue_; }
    inline uv_thread_t* worker_at(unsigned int index) { return &workers_[index]; }
    inline unsigned int worker_count() const { return worker_count_; }
  
    uv_thread_t* workers_;
    unsigned int worker_count_;
    TaskQueue global_queue_;
  };
  
  }  // namespace node
  
  #endif  // SRC_NODE_V8_PLATFORM_H_
  