tut.h

美国加州大学操作系统课程实验平台Nachos

     * Throws if false.
     */
    void ensure(const char* msg,bool cond)
    {
       if( !cond ) throw failure(msg);
    }

    /**
     * Tests two objects for being equal.
     * Throws if false.
     *
     * NB: both T and Q must have operator << defined somewhere, or
     * client code will not compile at all!
     */
    template <class T,class Q>
    void ensure_equals(const char* msg,const Q& actual,const T& expected)
    {
      if( expected != actual )
      {
        std::stringstream ss;
        ss << (msg?msg:"") << (msg?": ":"") << "expected " << expected << " actual " << actual;
        throw failure(ss.str().c_str());
      }
    }

    template <class T,class Q>
    void ensure_equals(const Q& actual,const T& expected)
    {
      ensure_equals<>(0,actual,expected);
    }

    /**
     * Tests two objects for being at most in given distance one from another.
     * Borders are excluded.
     * Throws if false.
     *
     * NB: T must have operator << defined somewhere, or
     * client code will not compile at all! Also, T shall have
     * operators + and -, and be comparable.
     */
    template <class T>
    void ensure_distance(const char* msg,const T& actual,const T& expected,const T& distance)
    {
      if( expected-distance >= actual || expected+distance <= actual )
      {
        std::stringstream ss;
        ss << (msg?msg:"") << (msg?": ":"") << "expected [" << expected-distance << ";" 
           << expected+distance << "] actual " << actual;
        throw failure(ss.str().c_str());
      }
    }

    template <class T>
    void ensure_distance(const T& actual,const T& expected,const T& distance)
    {
      ensure_distance<>(0,actual,expected,distance);
    }

    /**
     * Unconditionally fails with message.
     */
    void fail(const char* msg="")
    {
      throw failure(msg);
    }
  }

  /**
   * Walks through test tree and stores address of each
   * test method in group. Instantiation stops at 0.
   */
  template <class Test,class Group,int n>
  struct tests_registerer
  {
    static void reg(Group& group)
    {
      group.reg(n,&Test::template test<n>);
      tests_registerer<Test,Group,n-1>::reg(group);
    }
  };

  template<class Test,class Group>
  struct tests_registerer<Test,Group,0>
  {
    static void reg(Group&){};
  };

  /**
   * Test group; used to recreate test object instance for
   * each new test since we have to have reinitialized 
   * Data base class.
   */
  template <class Data,int MaxTestsInGroup = 50>
  class test_group : public group_base
  {
    const char* name_;

    typedef void (test_object<Data>::*testmethod)();
    typedef std::map<int,testmethod> tests;
    typedef typename tests::iterator tests_iterator;
    typedef typename tests::const_iterator tests_const_iterator;
    typedef typename tests::const_reverse_iterator 
                     tests_const_reverse_iterator;
    typedef typename tests::size_type size_type;

    tests tests_;
    tests_iterator current_test_;

    /**
     * Exception-in-destructor-safe smart-pointer class.
     */
    template <class T>
    class safe_holder
    {
      T* p_;
      bool permit_throw_in_dtor;

      safe_holder(const safe_holder&);
      safe_holder& operator = (const safe_holder&);

      public:
      safe_holder() : p_(0),permit_throw_in_dtor(false)
      { 
      }

      ~safe_holder()
      {
        release();
      }

      T* operator -> () const { return p_; };
      T* get() const { return p_; };

      /**
       * Tell ptr it can throw from destructor. Right way is to
       * use std::uncaught_exception(), but some compilers lack
       * correct implementation of the function.
       */
      void permit_throw(){ permit_throw_in_dtor = true; }

      /**
       * Specially treats exceptions in test object destructor; 
       * if test itself failed, exceptions in destructor
       * are ignored; if test was successful and destructor failed,
       * warning exception throwed.
       */
      void release()
      {
        try
        {
          if( delete_obj() == false )
          {
            throw warning("destructor of test object raised an SEH exception");
          }
        }
        catch( const std::exception& ex )
        {
          if( permit_throw_in_dtor ) 
          {
            std::string msg = "destructor of test object raised exception:";
            msg += ex.what();
            throw warning(msg);
          }
        }
        catch( ... )
        {
          if( permit_throw_in_dtor )
          {
            throw warning("destructor of test object raised an exception");
          }
        }
      }

      /**
       * Re-init holder to get brand new object.
       */
      void reset()
      {
        release();
        permit_throw_in_dtor = false;
        p_ = new T();
      }

      bool delete_obj()
      {
#if defined(TUT_USE_SEH)
        __try
        {
#endif
          T* p = p_; 
          p_ = 0;
          delete p;
#if defined(TUT_USE_SEH)
        }
        __except(handle_seh_(::GetExceptionCode()))
        {
          if( permit_throw_in_dtor )
          {
            return false;
          }
        }
#endif
        return true;
      }
    };

    public:
    typedef test_object<Data> object;    

    /**
     * Creates and registers test group with specified name.
     */
    test_group(const char* name)
      : name_(name)
    {
      // register itself
      runner.get().register_group(name_,this);
    
      // register all tests
      tests_registerer<object,test_group,MaxTestsInGroup>::reg(*this);
    };

    /**
     * This constructor is used in self-test run only.
     */
    test_group(const char* name,test_runner& another_runner)
      : name_(name)
    {
      // register itself
      another_runner.register_group(name_,this); 
    
      // register all tests
      tests_registerer<test_object<Data>,
                       test_group,MaxTestsInGroup>::reg(*this);
    };

    /**
     * Registers test method under given number.
     */
    void reg(int n,testmethod tm)
    {
      tests_[n] = tm;
    }

    /**
     * Reset test position before first test.
     */
    void rewind()
    {
      current_test_ = tests_.begin();
    }

    /**
     * Runs next test.
     */
    test_result run_next()
    {
      if( current_test_ == tests_.end() )
      {
        throw no_more_tests();
      }

      // find next user-specialized test
      safe_holder<object> obj;
      while( current_test_ != tests_.end() )
      {
        try
        {
          return run_test_(current_test_++,obj);
        }
        catch( const no_such_test& )
        {
          continue; 
        }
      } 

      throw no_more_tests();
    }

    /**
     * Runs one test by position.
     */
    test_result run_test(int n)
    {
      // beyond tests is special case to discover upper limit
      if( tests_.rbegin() == tests_.rend() ) throw beyond_last_test();
      if( tests_.rbegin()->first < n ) throw beyond_last_test();

      // withing scope; check if given test exists
      tests_iterator ti = tests_.find(n);
      if( ti == tests_.end() ) throw no_such_test();

      safe_holder<object> obj;
      return run_test_(ti,obj);
    }

  private:
    /**
     * VC allows only one exception handling type per function,
     * so I have to split the method
     */
    test_result run_test_(const tests_iterator& ti,safe_holder<object>& obj)
    {
      try
      {
        if( run_test_seh_(ti->second,obj) == false )
          throw seh("seh");
      }
      catch(const no_such_test&)
      {
        throw;
      }
      catch(const warning& ex)
      {
        // test ok, but destructor failed
        test_result tr(name_,ti->first,test_result::warn,ex);
        return tr;
      }
      catch(const failure& ex)
      {
        // test failed because of ensure() or similar method
        test_result tr(name_,ti->first,test_result::fail,ex);
        return tr;
      }
      catch(const seh& ex)
      {
        // test failed with sigsegv, divide by zero, etc
        test_result tr(name_,ti->first,test_result::term,ex);
        return tr;
      }
      catch(const std::exception& ex)
      {
        // test failed with std::exception
        test_result tr(name_,ti->first,test_result::ex,ex);
        return tr;
      }
      catch(...)
      {
        // test failed with unknown exception
        test_result tr(name_,ti->first,test_result::ex);
        return tr;
      }

      // test passed
      test_result tr(name_,ti->first,test_result::ok);
      return tr;
    }

    /**
     * Runs one under SEH if platform supports it.
     */
    bool run_test_seh_(testmethod tm,safe_holder<object>& obj)
    {
#if defined(TUT_USE_SEH)
      __try
      {
#endif
        if( obj.get() == 0 ) obj.reset();
        obj->called_method_was_a_dummy_test_ = false;

#if defined(TUT_USE_SEH)
        __try
        {
#endif
          (obj.get()->*tm)();
#if defined(TUT_USE_SEH)
        }
        __except(handle_seh_(::GetExceptionCode()))
        {
          // throw seh("SEH");
          return false;
        }
#endif

        if( obj->called_method_was_a_dummy_test_ )
        {
          // do not call obj.release(); reuse object
          throw no_such_test();
        }

        obj.permit_throw();
        obj.release();
#if defined(TUT_USE_SEH)
      }
      __except(handle_seh_(::GetExceptionCode()))
      {
        // throw seh("SEH");
        return false;
      }
#endif
      return true;
    }
  };


#if defined(TUT_USE_SEH)
  /**
   * Decides should we execute handler or ignore SE.
   */
  inline int handle_seh_(DWORD excode)
  {
    switch(excode)
    {
      case EXCEPTION_ACCESS_VIOLATION:
      case EXCEPTION_DATATYPE_MISALIGNMENT:
      case EXCEPTION_BREAKPOINT:
      case EXCEPTION_SINGLE_STEP:
      case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
      case EXCEPTION_FLT_DENORMAL_OPERAND:     
      case EXCEPTION_FLT_DIVIDE_BY_ZERO:
      case EXCEPTION_FLT_INEXACT_RESULT:        
      case EXCEPTION_FLT_INVALID_OPERATION:
      case EXCEPTION_FLT_OVERFLOW:
      case EXCEPTION_FLT_STACK_CHECK:
      case EXCEPTION_FLT_UNDERFLOW:
      case EXCEPTION_INT_DIVIDE_BY_ZERO:
      case EXCEPTION_INT_OVERFLOW:
      case EXCEPTION_PRIV_INSTRUCTION:
      case EXCEPTION_IN_PAGE_ERROR:
      case EXCEPTION_ILLEGAL_INSTRUCTION:
      case EXCEPTION_NONCONTINUABLE_EXCEPTION:
      case EXCEPTION_STACK_OVERFLOW:
      case EXCEPTION_INVALID_DISPOSITION:
      case EXCEPTION_GUARD_PAGE:
      case EXCEPTION_INVALID_HANDLE:
        return EXCEPTION_EXECUTE_HANDLER;
    };    

    return EXCEPTION_CONTINUE_SEARCH;
  }
#endif
}

#endif