Assertion.hpp
#if !defined (__ASSERTION_HPP)
#define __ASSERTION_HPP
/*
CoreLinux++
Copyright (C) 1999 CoreLinux Consortium
The CoreLinux++ Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The CoreLinux++ Library Library is distributed in the hope that it will
be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
/*
Assertion is the exception created when an assertion fails. It contains
type information so that clients may filter the types of assertion
violations that they catch. There are several types of assertion:
ASSERT( bool ) Enabled by #define ALL_ASSERTIONS. It is only used
inside the INVARIANT clause of a class declaration.
REQUIRE( bool ) Enabled by #define ALL_ASSERTIONS or
#define ASSERT_REQUIRE. This macro is used to
check precondtions for a function. If disabled
the macro is compiled away.
ENSURE( bool ) Enabled by #define ALL_ASSERTIONS or
#define ASSERT_ENSURE. This macro is used to check
postconditions. If disabled the macro is compiled
away.
CHECK( bool ) Enabled by #define ALL_ASSERTIONS or
#define ASSERT_CHECK. This macro is used to check
assumptions or to check calls to external functions
in the OS. Unlike REQUIRE and ENSURE when disabled
this macro expands to: if( !( exp )) {;} else
This expansion allows calls such as:
CHECK( DosSubAllocMem( ... ) == 0 );
to not be compiled away.
CHECK_INVARIANT Enabled by #define ALL_ASSERTIONS. This macro is
used to validate that the class INVARIANT still
holds. The INVARIANT must hold after construction
and at the end of any public member function. In
order to use this assertion the class must have an
INVARIANT ... END_INVARIANT section in the class
definition. If ALL_ASSERTIONS is not defined then
this macro expands to nothing.
NEVER_GET_HERE This macro is always enabled and throws an assertion
if it is ever executed. It should be used to make
explicit to the reader that all cases have been
accounted for in a switch or if ... else if ... else
block.
Typically the programmer defines ALL_ASSERTIONS during development and
reduces assertion levels to ASSERT_REQUIRE at beta and even into release.
In addition to the assertions there are several helper macros that allow
for class INVARIANTs and the logic predicates "for all" and "there exists".
There is also the USES_OLD macro which allows changes in a class to be
checked against the original version of the class.
BASE_INVARIANT( BaseClass ) Can only be used in the INVARIANT clause
of a class definition. This expands to call the
INVARIANT of one of the base classes in the
current class. Expands to: BaseClass::INVARIANT()
INVARIANT Can only be used inside a class definition. This
should be the last thing in the class and should
state the conditions that hold when the class is
correct. The only statements allowed in the
INVARIANT are BASE_INVARIANT and ASSERT.
For example an ordered array class may
look like:
class OrderedArray<T> : public Vector
{
public:
Array( int size ) :
Vector(),
theSize( size ),
theArray( new T[ size ] );
{
orderTheArray();
CHECK_INVARIANT;
}
virtual !Array();
// other operations.
private:
int theSize;
T * theArray;
INVARIANT
BASE_INVARIANT( Vector );
// Array is sorted in ascending order.
ASSERT( FORALL(( int i = 1; i < theSize; i++ ),
theArray[i-1] <= theArray[i] ));
END_INVARIANT
}; // end class OrderedArray<T>
END_INVARIANT Used to terminate the INVARIANT clause in a class
definition.
USES_OLD( Type ) Creates a copy of the current object called old
which can then be used in assertions to check
those attributes between the new object and old.
Any function which needs old must declare this
at the start of the function. The object must
be able to copy itself deeply for this to work
correctly. Only creates old if ALL_ASSERTIONS or
ASSERT_ENSURE is defined.
WARNING: old should only be used by the ENSURE
macro.
old variable created by the USES_OLD macro. A typical
use would be:
void List::addItem( item )
{
...
ENSURE( size() == old.size() + 1 );
}
bool FORALL(( for-specification ), condition )
Only expands if ALL_ASSERITONS is defined, and can only
be used in assertions. If ALL_ASSERTIONS is not defined
it becomes the value True. If expanded it becomes
equivalent to:
REQUIRE( FORALL(( int i = 0; i < 10; i++ ), x[i] <= x[0] ));
REQUIRE( tempForAll() );
bool tempForAll()
{
bool result = True;
for( int i = 0; i < 10; i++ )
if( !( x[i] <= x[0] ))
{
result = False;
break;
}
return result;
}
Be very carefull using this macro since errors
in the for specification or condition can be very difficult
to find. Also note that the condition can be another
FORALL or an EXISTS.
bool EXISTS((for-specification), condition )
Only expands if ALL_ASSERTIONS is defined, otherwise
becomes the value True. Returns True as soon as the
condition is met. If all iterations fail then the
macro fails. When expanded it becomes equivalent to:
ENSURE( EXISTS((int i = 0; i<10; i++), x[i] == old.x[i] ));
ENSURE( tempExists() );
bool tempExists()
{
bool result;
for( int i = 0; i < 10; i++ )
if( x[i] == old.x[i] )
{
result = True;
break;
}
return result;
}
The assertion mechanism also supports two functions; assertionFailed()
and assertLoopDebugFunction(). The first is called when an assertion
fails and after the assertion exception has been built. The second
one is called if FORALL or EXISTS fail. These functions are a handy
place to set breakpoints during debugging. They are implemented in
Assertion.cpp
See also: Object Oriented Software Construction
Bertrand Meyer.
Prentice Hall, Englewood Cliffs NJ., 1988.
C/C++ Users Journal October 1994 pages 21 - 37
*/
#if !defined IN_COMMON_HPP
#error Assertion.hpp is included by Common.hpp only.
#endif
namespace corelinux
{
// Standard class Declarations
DECLARE_CLASS( Assertion );
// These macros are called when an assertion fails or a FORALL or EXISTS
// test fails respectively. They provide a convienent place to set a
// breakpoint during debugging.
//
Long assertionFailed( AssertionCref rAssertion );
void assertLoopDebugFunction( void );
//
// Static variables needed by the assertion macros.
//
static Long asstInvert = 0;
static Long asstResult = 0;
static Long asstEval = 0;
static Long asstShortCut = 0;
static Long asstZero = 0;
static struct AssertCt
{
AssertCt( void )
{
asstInvert = asstResult = asstEval = asstShortCut = asstZero = 0;
}
// empty
} asstCt;
//
// Typedefs and Macros
//
#define paste(a,b) a##b
#define paste3(a,b,c) a##b##c
#if defined ALL_ASSERTIONS || defined ASSERT_REQUIRE
#define REQUIRE( exp ) \
IGNORE_RETURN ( \
asstResult = asstZero || exp, \
asstResult || assertionFailed( Assertion( Assertion::REQUIRE, \
TEXT( #exp ), \
LOCATION \
)) )
#else
#define REQUIRE( exp )
#endif // defined ALL_ASSERTIONS || ASSERT_REQUIRE
#if defined ALL_ASSERTIONS || defined ASSERT_ENSURE
#define ENSURE( exp ) \
IGNORE_RETURN ( \
asstResult = asstZero || exp, \
asstResult || assertionFailed( Assertion( Assertion::ENSURE, \
TEXT( #exp ), \
LOCATION \
)) )
#else
#define ENSURE( exp )
#endif // defined ALL_ASSERTIONS || ASSERT_ENSURE
#if defined ALL_ASSERTIONS || defined ASSERT_CHECK
#define CHECK( exp ) \
IGNORE_RETURN ( \
asstResult = asstZero || exp, \
asstResult || assertionFailed( Assertion( Assertion::CHECK, \
paste3( \
TEXT("CHECK( "), \
TEXT( #exp ), \
TEXT(" )") \
), \
LOCATION )) )
#else
#define CHECK( exp )
#endif // defined ALL_ASSERTIONS || ASSERT_CHECK
#define NEVER_GET_HERE \
assertionFailed( Assertion( Assertion::NEVERGETHERE, \
TEXT("NEVER_GET_HERE"), \
LOCATION ))
//
// Macros that support class INVARIANTs.
//
#if defined ALL_ASSERTIONS
#define INVARIANT \
protected: \
virtual void invariant(void) const { Short executingInvariant = 1;
#define END_INVARIANT }
#define CHECK_INVARIANT invariant()
#else
#define INVARIANT paste(/, *)
#define END_INVARIANT
#define CHECK_INVARIANT
#endif
/*
paste3( \
TEXT("STDASSERT( "), \
TEXT( #exp ), \
TEXT(" )") \
), \
*/
#if defined ALL_ASSERTIONS
#define STDASSERT( exp ) \
if( executingInvariant ) \
{ \
asstResult = asstZero || exp, \
asstResult || \
assertionFailed( Assertion( Assertion::ASSERT, \
TEXT( #exp ), \
LOCATION )); \
} \
else \
{ \
throw Exception( \
TEXT("STDASSERT used outside of INVARIANT"), LOCATION ); \
}
#else
#define STDASSERT( exp )
#endif // defined ALL_ASSERTIONS
#if defined ALL_ASSERTIONS
#define BASE_INVARIANT( ClassType ) \
if( executingInvariant ) \
{ \
ClassType::invariant(); \
} \
else \
{ \
throw Exception( \
TEXT("BASE_INVARIANT used outside of an INVARIANT"), \
LOCATION, \
Exception::ProcessTerminate); \
}
#else
#define BASE_INVARIANT( ClassType )
#endif
//
// Macro that defines "old".
//
#if defined ALL_ASSERTIONS || defined ASSERT_ENSURE
#define USES_OLD( Type ) Type old( clself )
#else
#define USES_OLD( Type )
#endif
//
// Macros for FORALL and EXISTS
//
#define ASSERT_LOOP( asstFor, asstAll, asstCond ) \
anAssertCt(); \
{ \
volatile x = 0; \
Long asstShortCut; \
if( asstDoEval( asstShortCut )) \
{ \
Long asstInvert = ::asstInvert; \
asstResult = asstAll; \
for asstFor \
{ \
asstResult = x || asstCond; \
if( asstResult != asstAll ) break; \
} \
if(asstInvert) asstResult = !asstResult; \
} \
::asstShortCut = asstShortCut; \
if( asstResult == 0 ) assertLoopDebugFunction(); \
} \
asstResult = ::asstShortCut ? asstResult : asstResult
#if defined ALL_ASSERTIONS
#define FORALL(asstFor, asstCond ) ASSERT_LOOP( asstFor, 1, asstCond )
#define EXISTS(asstFor, asstCond ) ASSERT_LOOP( asstFor, 0, asstCond )
#else
#define FORALL(asstFor, asstCond ) True
#define EXISTS(asstFor, asstCond ) True
#endif
//
// Constants
//
//
// Helper Classes (including exceptions).
//
class Assertion : public Exception
{
//
// Note that a private default constructor is not needed
// beause Exception's default constructor is private.
//
public:
enum Type
{
REQUIRE,
ENSURE,
CHECK,
ASSERT,
NEVERGETHERE
};
public:
Assertion
(
Type aType,
CharPtr aReason,
CharPtr aFile,
LineNum aLine
);
Assertion( AssertionCref rExcept );
virtual ~Assertion( void );
//
// Operator overloads
//
AssertionRef operator=( AssertionCref );
bool operator==( AssertionCref );
//
// Accessors
//
Assertion::Type getType( void ) const;
private:
Assertion::Type theType;
};
//
// Inline Functions
//
inline AssertCt & anAssertCt( void )
{
asstInvert = 0;
asstEval = 1;
return asstCt;
};
inline Long asstDoEval( Long & asstShortCut )
{
Long result = asstEval;
asstShortCut = !asstEval && asstResult;
asstEval = 0;
return result;
}
inline const AssertCt & operator !( const AssertCt & a )
{
asstInvert = !asstInvert;
return a;
}
inline Long operator &&( Long left, const AssertCt & )
{
asstEval = left;
return left;
}
inline Long operator ||( int left, const AssertCt & )
{
asstEval = !left;
return left;
}
}
#endif // !defined ASSERT_HPP
/*
Common rcs information do not modify
$Author: prudhomm $
$Revision: 1.1 $
$Date: 2000/04/23 20:43:13 $
$Locker: $
*/
corelinux::Assertion::ASSERT
CHECK invariant state.
Definition: Assertion.hpp:439
corelinux::Assertion::NEVERGETHERE
ASSERT invariant state.
Definition: Assertion.hpp:440
corelinux::Assertion::Assertion
Assertion(Type aType, CharPtr aReason, CharPtr aFile, LineNum aLine)
Assertion Constructor.
Definition: Assertion.cpp:48
corelinux::Assertion::operator=
AssertionRef operator=(AssertionCref)
Assignment operator overload.
Definition: Assertion.cpp:86
corelinux::Assertion::operator==
bool operator==(AssertionCref)
Comparisson operator overload.
corelinux::Assertion::~Assertion
virtual ~Assertion(void)
Virtual Destructor.
Definition: Assertion.cpp:77
corelinux::Assertion::ENSURE
REQUIRE pre-condition state.
Definition: Assertion.hpp:437
corelinux::Exception
Exception is the base exception class used in the CoreLinux++ libraries.
Definition: Exception.hpp:51
corelinux::Assertion
Assertion is-a Exception created when an assertion fails.
Definition: Assertion.hpp:423
corelinux::Assertion::Type
Type
Assertion Types enum.
Definition: Assertion.hpp:434
corelinux::Assertion::CHECK
ENSURE post-condition state.
Definition: Assertion.hpp:438
corelinux::Assertion::getType
Assertion::Type getType(void) const
Accessor.
Definition: Assertion.cpp:104

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