Understanding the source code

[AstroDog]

Hey! I have gone through the source code to some extent and have made successful changes but I don't understand the overall workings of the code. So my questions is how can I understand it fully? And also where can I learn WTL? Good someone perhaps by a quick example tell me how to for example add a button under the menubar or limit the download speed so that the source is changed if dl-speed is less than let's say 5 kb/s or similar, and perhaps also how to add an option for this in the settingsdialog. Of course clear code would be the best but I can think for myself and a general outline of how this should be written would be sufficient for me. Also I would like a general discussion of DC++-code in general, things that I always have to think about etc... for example locks, what are they? I am pretty familiar with winapi but have never used mfc,atl or wtl. Anyone know any good e-books or books on WTL? Or perhaps a site with a tutorial?

Thanks in advance, Martin, Sweden

[GargoyleMT]

You have so many questions/requests in your message that I can't possibly answer any of them.

Well, maybe just one or two...

As for the adding a menu option just take a look. You'll need to add menu entries in WinUtil.cpp, and methods to handle them in MainFrm.cpp/h. Don't forget the strings in the StringDefs.

Take a look at the settings dialogs, they're pretty easy to add.

For changing sources, that'd be an excellent feature, it's been requested. You'll have to add a int setting to the SettingsManager, a string to StringDefs.cpp/h, an entry for the setting in AdvancedPage.cpp. Then comes the actual implementation of the code. You'll need to modify the DownloadManager, I'd probably add a rolling-5 second average speed to the members (if not 30 or minute), to smooth out the measurement. You might not be able to easily determine if there's another source for a given file, so you might have to add some hooks in to the QueueManager.

I hope this helps. Of course, it's only generalities, but if I gave specifics, I'd be writing the feature.

[AstroDog]

Although I really would need a real coded example cause I am so not familiar with all the terminology of hooks and locks but I am confident (yeey =) that I would understand them with just a coded example and a few lines of good tutoring text, hehe. And of course the WTL-book if there exists one. Preferably a free PDF-version cause I have zero cash right now. Not that you care about my financial situation *smileyspamming*

But I will give a go at the changing of dl-source. I did remember seeing something like onTimerSecond already in the DownloadManager I believe so just copy'n'paste'n'modify ehrr.. yea =)

[GargoyleMT]

Well, if you look at the source and don't understand some of it, I'll gladly explain specifics and write some code to explain. Your initial barrage of questions was overwhelming. Just dive in to the source, and come back here if you need some air. It's how I got where I am, which isn't very far.

I haven't found a good WTL/ATL reference, by the way - even the ATL references in Visual Studio .NET are outdated - referring to 3.1 - and the WTL 7 distribution from MS seems to have no help files. I haven't looked for real books, though. If you dive into the .h files, you'll see that they're just wrappers, mostly, for win32 code [which you seem to be familiar with].

[AstroDog]

Download::Download(QueueItem* qi) throw() : source(qi->getCurrent()->getPath()),
target(qi->getTarget()), tempTarget(qi->getTempTarget()),
comp(NULL), bytesLeft(0), rollbackBuffer(NULL), rollbackSize(0)

someone please explain this code since I don't understand anything of it, with all the : and etc.. Is this basic C++ that I don't know or what?

Thanx, Martin

[GargoyleMT]

That's one way of initializing member variables in a constructor. It's a little nicer than having it in the function body, imho.

[AstroDog]

So I presume source(qi->getCurrent()->getPath()) would be equivalent of source = qi->getCurrent()->getPath(); or even some method source(qi->getCurrent()->getPath()) but problem is I can't find neither a variable nor a method. So how does that initializing work?

And what is this here below that I see everywhere?
Lock l(cs);

Sorry if i am being a pain =)

[GargoyleMT]

Look at GETSETREF() and GETSET() - they're macros, and they define a member variable plus functions to get and change it.

Lock l(cs) is about critical sections. Some of the code is not (can not be) designed to be reentrant, and DC++ is multithreaded, so you need to protect certain things with critical sections.