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#ifndef GEARS_DATABASE2_INTERPRETER_H__
#define GEARS_DATABASE2_INTERPRETER_H__

#include "gears/base/common/common.h"
#include "gears/base/common/scoped_refptr.h"

// forward class declarations
class Database2Command;

// simple (non-threaded) command interpreter
class Database2Interpreter : public RefCounted {
 public:
  // TODO(dimitri.glazkov): Because the sub-class depends on ref-counting to
  // keep track of when to shut down a thread, this base class is also
  // ref-counted. However, its counting is effectively rendered useless by
  // Ref'ing in constructor. This is awkward. Must think of a better pattern
  // here.
  Database2Interpreter() {
    // increment ref to prevent from ever being destroyed
    if (!async()) Ref();
  }
  ~Database2Interpreter() {}

  virtual void Run(Database2Command *command);
  virtual bool async() const { return false; }

 private:
  bool async_;

  DISALLOW_EVIL_CONSTRUCTORS(Database2Interpreter);
};

// threaded interpreter
class Database2ThreadedInterpreter : public Database2Interpreter {
 public:
  Database2ThreadedInterpreter() {}
  ~Database2ThreadedInterpreter() {
    // shut down thread, if started
  }

  virtual void Run(Database2Command *command);
  virtual bool async() const { return true; }

 private:
  DISALLOW_EVIL_CONSTRUCTORS(Database2ThreadedInterpreter);
};

#endif // GEARS_DATABASE2_INTERPRETER_H__