Direct Connect: Just These Guys, Ya Know?

DC++ 0.799

A new bugfix release of DC++ is out today, this time it’s really meant to be the next stable one. Along with two important stability fixes and another fix for a problem with locales the changes include only small fixes, improvements and library updates. If you’re already using 0.797 then it’s worth to head over the download page and get the update right away.

If everything goes well this new release will be marked stable within a few days.

DC++ 0.797

A new DC++ release is out and it has a rather uncommon leap in the versioning. There’s no any special reason of choosing 0.797 – maybe we’re approaching 0.800 faster this way :)  The current offering mainly focuses on style improvements and reliability fixes but there’s no shortage of the usual smaller developments, either.

Let’s see the important areas affected by this release:

Partial file lists

Capability of getting only parts of a user’s file list instead of the whole one is included in DC++ for quite a while (jeez it’s been more than 6 years – time surely flies).  The function is available using the ‘Browse file list’ item in the context menu of user lists. Even if browsing file list capability is there for a while, still not too many users are actually faced it, at least not in DC++. The reason is that partial lists are defined in the ADC protocol only, thus DC++ has supported this feature on ADC hubs only.

Partial file lists are displayed in a similar window as the old, well known complete ones. However, functions like startup restoration and ADL Search haven’t been available for the partial list windows until now. As an improvement, file list windows now introduce a new button called “Download full list” which is primarily made for an easy upgrade from a partial list to a full one in case of you decide that you need the full list of the user. The button is even useful for fully downloaded lists as well: you can easily refresh the file list when eg. you suspect that the user may modified it since the last download.

File list window

The code responsible for partial file requests between peers (what makes browsing of others’ file lists possible) has also received a nice improvement. Until now the browse function was able to receive the content of only one folder in one go. If you clicked a folder in the list you got its contents – but only the files and in one level deep only in the folder structure. No more no less, not even the content of the subdirectories. That needed another click (and another partial list request).

This has changed with 0.797 as we introduced heuristics for sending additional levels of information with partial file lists requests. What does this mean? If you give it a try you’ll understand right away: you should get much more contents of the surrounding folder structure in one request. All of this was done the way that only an acceptable amount of additional data are transferred in a particular request – which means that it does not slow down the browsing experience at all.

Pretty useful improvement, the only drawback is that it’s obiviously not backward compatible (needs at least DC++ 0.797 or based client on the other side). This means that browsing lists of older clients will behave the same as like before.

Above all of the good news about partial lists, I saved probably the best for last: from now Browse file list is a available for NMDC hubs as well. This might come as a suprise given the fact that the DC++ author has annouced a feature freeze for NMDC related things a while ago. But actually this isn’t a protocol change, even not a feature update, it is the same hack as the one that other DC clients have successfully used for a long time: the NMDC “protocol” is so weak that it allows anything to send and receive in the state of an estabilished client-client connection. This means that the browse function simply uses the appropriate ADC command for partial list requests on NMDC and it’ll be accepted and served. Sounds dumb but it works…

As you learned above, partial list support in DC++ has been around since about 6 years ago, this means that older clients may appear on NMDC hubs won’t let you browse their lists (to be exact it’s core version 0.670 and above needed on the other side). Browsing lists of these ancient dinosaurs will result an error message in the transfer view.

Away mode

User status indication is an important part of instant messaging and we know that DC++ incorporates such feature. A typical IM system includes many status modes, like Busy, N/A, etc.., DC++ has only two: Online and Away. Until now away mode could have been set only in manual ways, either by directly switching it on or by minimizing the application (when the appropriate setting was enabled). Furthermore, in away mode a message was always sent as a reply to incoming private messages; either the default away message or a custom set one.

DC++ 0.797 now brings the bare minimum configurable options users expect these days in this regard:

Away mode settings in Personal Information pane

First of all the away message sent as a reply to pm’s in away mode is made optional so you can avoid it completly if you want. Secondly you are able to switch the away mode on automatically after some time of user inactivity and of course back when a mouse or keyboard event happens. As a third and last improvement you can enable a similar automatic away mode on-off switch for when the Windows user account is become locked and unlocked.

GUI  & Styles

Connected hub with link styles improvements

The most obivious styles improvement is clear from the above screenshot; configurable link styles is a function that many people missed over the years. Also note the format of the magnet link in the last line of the chat shot above. Magnets are shown in a new standout style as well as in a new human readable format.

Another freely configurable option is the color and style of the displayed chat history in the pm windows.

Both new options are available in the Styles pane in the Settings window and both have a resonable default value, generated automatically by taking the current application color style in account.

Additionally, existing user matching definition styles that made for nicks in the userlist are now also applied to the nicknames appear in the chat windows. To stand out every nick in the chat you can even easily apply the same style for all nicks if you wish to. For easy configuration, DC++ is shipped with two predefined user matching definitions for favorite users (bold, more red) and operators (more blue).

Along with the configurable link styles the way of following the hub redirect requests has also changed. The ambigous Follow Redirects toolbar button is gone and now users can follow the redirect manually by clicking a link-like announcement in the main chat of the corresponding hub window. This is less confusing than having a global button in the toolbar which actually had no function most of the time.

Beside the bigger GUI improvements the newest version of DC++ comes with a few other less significant changes. They’re as follows:

• Finally reduced the ugly flickering that happens in the chat window when it’s scrolling. You’ve been able to observe this problem since DC++ chat windows have switched to Richedits in order to be able to display styled text. The proper solution of the problem was borrowed from StrongDC++ and if you think this is something trivial and should have been easily fixed a long time ago then you’re wrong. Several (I mean, several) attempts has been made to fix this before. Welcome to the nightmare of Richedit.
• Now you can see the last chat line in taskbar previews so you can easily manage to switch to the right chat window if you use Windows 7 and you chat in multiple hubs or with multiple people at the same time.
• If you open up the Settings dialog and hover the mouse over the controls you’ll see the new context-sensitive help tooltips appear. Useful feature for the lazy ones as well as it provides fast way to discover unknown customization possibilities.
• Multiple monitor support is also improved. From now when you start DC++ the main window will re-appear in exactly the same position as it was left before, regardless of number of monitors used.

Stability & reliability

As usual we introduce a few stability fixes as well, most notably the one which causes crash on startup/shutdown or when some content added or modified in the download queue. A possible memory leak was also fixed during the file list matching operations.

DC++ is also improved for Windows XP users as two bugs specific to this OS is fixed in 0.797:  one of them is messing up the favorite hubs window if you try to modify or move any entry in it. The other bug fixed keeps Win XP users from providing useful crash logs with the built- in crash logger function (probably this bug was the reason of  those many less useful crash logs reported as the Windows XP userbase is still quite large).

File reading operations also improved in general. Until now the most optimal method for file readings has been possible to use  for hashing only and it was optional – you had to manually disable it if problems encountered. From now the most optimal method is used by default for every file reads with automatic fallback to the old method in case of problems.

I believe the new features and fixes are discussed here in great detail but if you curious about every tiny bit of improvements then refer to the changelog as usual.

Have fun using the new version but also prepare for DC++ 0.800 which – if everything goes well – will be the version number of the next DC++ release. You might be suprised as it has to come with at least one brand new and interesting featrue :)

DC++ 0.791

As a result of a 9 month long development, we’re glad to introduce a new stable version of DC++ released to the public a few weeks ago. This time the development mainly focused to add new useful GUI elements as well as revamp some exitsing ones. Further improvement has been made on the automatic connectivity setup so from now it is equally efficient for the everyday user and for expert people. The changelog for version 0.790 counts exactly 60 different changes with many improvements and bug fixes. Version 0.791 is a package update only it contains the same code as 0.790 marks it as a stable release. DC++ 0.79x patches a currently undisclosed security vulnerability, too.

Let’s see some areas with important changes in detail:

GUI changes

First of all, the new release adds one brand new frame and removes two old ones. Don’t worry, nothing’s lost, it’s only some rationalization in the funcions. There is a future plan to merge distributed functions in DC++ as much as possible and you can consider this as a first step on the way. From now Favorite users frame becomes Users frame, shows all users and it is equipped with powerful filtering capabilities. Those filters allow you to display favorite or waiting users only, so the separate frames used for manage them become redundant.

Users frame

The last major release showed a big overhaul on the searching capability of the file list windows, now there’s more:  the file list status bar buttons moved to the toolbar, and instead the progress of file list searches are shown in the status bar. Two useful things were also added as searches within file lists continue from the beginning after reaching the end while the window manager saves/restores the current directory position of the file lists – in other words when a file list window is restored you’ll be taken back to exactly where you’ve been last time.

If you open up the Settings window you’ll see a nice visual overhaul with new icons in the category view and perfectly aligned placement of the boxes.  And it’s not only been made nicer looking because of a call for better looking dialogs, there’s more: the window is resizable as you wish and at last the dialog remembers the last used pane after closal. Yeah, the hassle of  endless navigation to the same pane is gone in case you want to play with certain group of  settings. And there are even new settings panes for brand new functions as follows:

The former Colors and Sounds pane under the Apperarence settings are divided to Styles and Notifications and both  halves are greatly improved. As like before, you can still define the global visual style of the application and the file transfers (the former is now applied even more accuratley throughout the program) but you can do it in a much cleaner interface with an immediate preview of how the defined styles will look like. As a brand new function you’re able to define visual styles (various colors, font face and styles) for displaying certain nicks in the user list of the hub window. You can create user matching definitions that determine certain groups of users so you are able to set their appearence in the user list accordingly.

Style settings

User matching itself is also a new function debuting in the 0.79x series of DC++.  It has its own new configuration pane in the Settings where you can define an unlimited number of rules determining certain groups of online users by filtering them out by their properties.  The user matching function is added to the core (dclib);  and not only because of the obivious reason that other clients can also benefit from it this way. Currently it is used only for stylize the user list, but there can be several other future ideas that can use this function as their base, like automatic operations on group of users that match certain criteria, etc…

User matching settings

Another good news is that DC++ 0.791 introduces two evident functions that p2p software can’t miss nowadays. Bandwidth limiting has already been added a few versions before but its configuration was rather complicated as the user always had to open the Settings dialog in order to modify the limiting values. The most obivious and quickest possible solution has been created, a menu interface that is avaliable from the tray menu or by clicking to the limiting value indicators in the status bar. This quick value change interface is well known and you might familiar with it from other p2p applications.

By upgrading to 0.791 you’ll also get a totally revamped notification system as well. It’s possible to configure balloon popup  and/or  sound notifications for different events. Another long time missing function that others implemented long ago…

Notifications’ settings

And at last but not least: list filters are greatly improved throughout the interface, even added a new one to for filtering search results. Just try them out to see how easy and effective it has become… you’re even able to use regular expressions to filter out your results!

Connectivity

Connectivity features are improved a lot in the last versions of DC++ and in fact it would worth to dedicate a separate post about the insights of the Automatic Connectivity Setup (formerly known as “Automatic Connection Detection”) which is one of the largest usability improvements in DC++ over the recent years.  You can learn the basics of the feature here (you’ve probably seen it working in the real world anyway).

0.791 brings some more fine tuning to the connectivity setup: there was a complete reorgainization both under the hood and in the settings GUI resulting simpler code and a total separation of basic (automatic) and advanced (manual) connectivity setup. While the former provides a foulproof automatic setup with zero configuration for the majority of users, the latter retains the flexibility of manual set up of each and every option.

This reorganization of the storage of the connectivity settings allowed to add an interesting new feature that makes connection between the automatic and the manual way of setup. Think of the situaton where the automatic connectivity setup fails because it is unable to detect one of the required parameters, while ot still detects many of them correctly. This is when the new “Edit Detected Settings” function comes to play:  it overwrites the manual settings with the automatically detected ones thus it allows you correct the wrongly detected setting(s) manually.  So when the automatic detection fails it may still worth to copy the detected set of settings and use them as a hint for the manual setup.

Connectivity Settings

Another improvement is that in a multi-network enviroment you can clearly set up what gateway should be used to create the automatic port mappings. It means that from now the port mapper will always use the network interface that all other connections bound to. For easier troubleshooting of MiniUPnP (which is the mapper used most times) the name of the device the mapper has bound to will be displayed as a part of the log message shown after a successful mapping operation.

The last but far not the least important improvement in the connectivity area is the introduction of  NAT-PMP support for port mappings as an alternative to UPnP. This quickly emerging protocol is known from its simplicity and there’s a growing number NAT-PMP supporting consumer router devices in the market as well. However, you must consider NAT-PMP support as beta at least for the time being.

More news from under the hood

Improvements in DC Library is always a nice thing since usually the large part of the DC community can benefit from them. It’s even better when old features are reintroduced, features that are existed before but have been temporarily disabled for a while for various reasons.

One of these features is the finished downloads log which has been missing since the introduction of segmented downloads. Altough aligning this function to log only the completed downloads instead of the individual finished segments sounds trivial in theory, actually it needed a complete rethink and replacement of the code. It wasn’t on the top priority list, either (hence the late fix) but certainly a welcomed feature for a few people.

Automatically generated crash logs is the other feature to be reintroduced and surely is the more important one. It has been missing since the development of DC++ switched to an open source compiler that has no native capability of providing crash logs. These logs, when reported back to the developers, are really useful and speed up the fixing of serious bugs. libdwarf has been added to generate human readable crash logs from the call stack using the debug symbols database (.pdb file, shipped in the release package again).

If you encounter a crash you can open the last crash log from within DC++ using the “Open crash log” item from the File menu (or find the log file itself in the Local Appdata folder in case of a startup crash – it’s called “Crashlog.txt”). To help the development you’re now able (and encouraged) to report any crash logs to the official DC++ bug tracker.

As you might read about the feature before, DC++ switched to binary GeoIP databases and added the IPv6 one as well. Moreover the country format shown beside the IP adresses can be highly customized (see the help for all the possible ways). DC++ 0.791 handles GeoIP database updates automatically from within the program so cases when wrong country information displayed for users should be greatly reduced as well as you can forget the hassle of manual updating of the database files from the GeoIP servers.

Stability, performance and  security

Here’s a short list of most important improvements in these areas:

• You’ll experience a really faster startup when many tabs to be restored
• File lists are loaded in a separate thread (no GUI freeze with large lists anymore)
• A possible crash fixed when searching within too big file lists
• Fixed a possible crash on removal of parital lists from the queue (details will be published later)
• Fixed a problem that could cause freezes and unwanted behaviour on long time running
• DC++ is explicitly shows that it supports and encourages the operating system to enable DEP and ASLR when executed (the latter is available for Vista and later)

That’s it for today, enjoy and prepare for a new release, it should arrive soon!