Re: Request final critique
On Jun 14, 11:31 pm, "RB" <NoMail@NoSpam> wrote:
// in MyDocClass header file
.............
protected:
CMapStringToString ExpMap1;
struct VerStruct
{
CString Ver, CpyRt, Corp;
};
VerStruct VerData;
DWORD FileID;
.............
// in MyDocClass constructor
CFileHandlingDoc::CFileHandlingDoc( )
{
// Fetch stuff from included AppVer.h file that also
// feeds all App requests for version data, that idea
// courtesy of David Webber
VerData.Ver.Format( _T("Version %d.%d.%d.%d"),
VERMAJ, VERMIN, VERFIX, BUILDNUMBER );
VerData.CpyRt = _T(CPY_RIGHT_YR);
VerData.Corp = _T(CORP_NAME);
FileID = 0x1234ABCD;
}
// and in MyDocClass Serialize func
void CFileHandlingDoc::Serialize(CArchive& ar)
{
if (ar.IsStoring( ) )
{
ar << FileID;
ar << VerData.Ver << VerData.CpyRt << VerData.Corp;
ar.SerializeClass(RUNTIME_CLASS(CMapStringToString));
ExpMap1.Serialize(ar);
}
else
{
ar >> FileID;
if (FileID != 0x1234ABCD)
{
CWnd* pWnd = AfxGetMainWnd( )->GetActiveWindow( );
pWnd->MessageBox( _T("Incorrect File format, operation aborted=
"),
_T("! ALERT !"), MB_OK | MB_ICONINFORM=
ATION );
return;
}
It's a bad idea to put up a message box in the middle of
serialization. You should throw an exception with appropriate info in
it (that's what's going to happen anyhow for reasons outside your
control, and that's what MFC expects to happen).
This will cause ReportSaveLoadException to be called and error message
will be shown. Document will consequently fail to load. What you did
is, you failed to lad, inform the user, but you continued as if you
did load the document. That's a ___bad___ idea.
ar >> VerData.Ver >> VerData.CpyRt >> VerData.Corp;
if (VerData.Ver.Right(7) == _T("1.0.0.0"))
{
ar.SerializeClass(RUNTIME_CLASS(CMapStringToString));
ExpMap1.Serialize(ar);
}
if (VerData.Ver.Right(7) == _T("1.0.0.1"))
{
// 1.0.0.1 stuff
}
}
}
Minor point: you should not be using string (text) information for
version. You have numbers anyhow, use them.
Major point: you should also not tie your executable version to these
if-s there. Look at it this way: over the time, you will add features
and bug fixes, and there will hundreds, if not thousands of them. Many/
most of them will not require change to serialization, so your if-s
are simply misguided. If you go on with this, you will repeat all
serialization code in each version. That's not how things usually work
(exception in development, before feature stabilizes). Only from time
to time, you may have significant enough changes to warrant "big"
version switches like you have there.
This is what we do at my work: we have "general" document version (a
number). Each time we change the schema, we bump that number, (as well
the schema number in the appropriate class). Each release knows it's
own "general" schema number, and so, upon load, we can say, whoops,
this file is newer, I don't support that (we only support backwards
compatibility; that works well enough, because normally new files mean
new features mean new code to run them).
e.g.
const int GENERAL_DOC_VERSION=X;
doc::Serialize()
{
load:
...
int generalDocVersion;
ar >> generalDocVersion;
if (generalDocVersion > GENERAL_DOC_VERSION)
ExceptionTooNew();
...
store:
...
ar << GENERAL_DOC_VERSION
...
}
Goran.