<![CDATA[KDE - Technically Correct]]>http://arnavdhamija.com/http://arnavdhamija.com/favicon.pngKDE - Technically Correcthttp://arnavdhamija.com/Ghost 2.1Wed, 19 Sep 2018 20:37:00 GMT60<![CDATA[Akademy 2017]]>Last month, I attended KDE's annual conference, Akademy. This year, it was held in Almeria, a small Andalusian city on the south-east coast of Spain.

The name of the conference is no misspelling, it's part of KDE's age old tradition of naming everything to do with KDE with a 'k'.

http://arnavdhamija.com/2017/08/17/akademy-2017/5b72ef510057007605e22d3eThu, 17 Aug 2017 14:30:00 GMT

Last month, I attended KDE's annual conference, Akademy. This year, it was held in Almeria, a small Andalusian city on the south-east coast of Spain.

The name of the conference is no misspelling, it's part of KDE's age old tradition of naming everything to do with KDE with a 'k'.

Akademy was a collection of amazing, life-changing experiences. It was my first solo trip abroad and it taught me so much about travel, KDE, and getting around a city half-way accross the world from home.


My trip began from the recently renamed Kempegowda International Airport, Bangalore. Though the airport is small for an international airport, the small size of the airport works to its advantage as it is very easy to get around. Check-in and immigration was a breeze and I had a couple of hours to check out the loyalty card lounge, where I sipped soda water thinking about what the next seven days had in store.

The first leg of my trip was on a Etihad A320 to Abu Dhabi, a four hour flight departing at 2210 on 20 July. The A320 isn't particularly unique equipment, but then again, it was a rather short leg. The crew onboard that flight seemed to be a mix of Asian and European staff.

Economy class in Etihad was much better than any other Economy class product I'd seen before. Ample legroom, very clean and comfortable seats, and an excellent IFE system. I was content looking at the HUD-style map visualisation which showed the AoA, vertical speed, and airspeed of the airplane.

On the way, I scribbled a quick diary entry and started reading Part 1 of Sanderson's Stormlight Archive - 'The Way of Kings'.

Descent to Abu Dhabi airport started about 3:30 into the flight. Amber city lights illuminated the desert night sky. Even though it was past midnight, the plane's IFE reported an outside temperature of 35C. Disembarking from the plane, the muggy atmosphere hit me after spending four hours in the plane's air-conditioned cabin.

The airport was dominated by Etihad aircraft - mainly Airbus A330s, Boeing 787-8s, and Boeing 777-300ERs. There were also a number of other airlines part of the Etihad Airways Partners Alliance such as Alitalia, Jet Airways, and some Air Berlin equipment. As it was a relatively tight connection, I didn't stop to admire the birds for too long. I traversed a long terminal to reach the boarding gate for the connecting flight to Madrid.

The flight to Madrid was another Etihad operated flight, only this time on the A320's larger brethren - the A330-200. This plane was markedly older than the A320 I had been on the first leg of the trip. Fortunately, I got the port side window seat in a 2-5-2 configuration. The plane had a long take-off roll and took off a few minutes after 2am. Once we reached cruising altitude, I opened the window shade. The clear night sky was full of stars and I must have spent at least five minutes with my face glued to the window.

I tried to sleep, preparing myself for the long day ahead. Soon after waking up, the plane landed at Madrid Barajas Airport and taxied for nearly half-an-hour to reach the terminal. After clearing immigration, I picked up my suitcase and waited for a bus which would take me to my next stop - the Madrid Atocha Railway Station. Located in the heart of city, the Atocha station is one of Madrid's largest train stations and connects it to the rest of Spain. My train to Almeria was later that day - at 3:15 in the afternoon.

On reaching Atocha, I got my first good look at Madrid.

Akademy 2017

My facial expression was quite similar

Akademy 2017

I was struck by how orderly everything was, starting with the traffic. Cars gave the right of way to pedestrians. People walked on zebra crossings and cyclists stuck to the defined cycling lanes. Things taken for granted in developed countries looked like a world apart from Bangalore. Shining examples of Baroque and Gothic architecture were scattered among newer establishments.

Having a few hours to kill before I had to catch my train, I roamed around Buen Retiro Park, one of Spain's largest public parks. It was a beautiful day, bright and sunny with the warmth balanced out by a light breeze.

My heavy suitcase compelled me to walk slowly which made me take in as much as I could. Retiro Park is a popular stomping ground for joggers, skaters, and cyclists alike. Despite it being 11am on a weekday, I saw plenty of people jogging though the Park. After this, I trudged through some quaint neighbourhoods with cobbled roads and old apartment buildings dotted with small shops on the ground floor.

Maybe it was the sleep-deprivation or dehydration after a long flight, but everything felt so surreal! I had to pinch myself a few times - to believe that I had come thousands of miles from home and was actually travelling on my own in a foreign land.

I returned to Atocha and waited for my train. By this time, I came to realise that language was going to be a problem for this trip as very few people spoke English and my Spanish was limited to a few basic phrases - notably 'No hables Espanol' and 'Buenos Dias' :P Nevertheless, the kind folks at the station helped me find the train platform.

Trains in Spain are operated by state-owned train companies. In my case, I would be travelling on a Renfe train going till Almeria. The coaches are arranged in a 2-2 seating configuration, quite similar to those in airplanes, albeit with more legroom and charging ports. The speed of these trains is comparable to fast trains in India, with a top speed of about 160km/hr. The 700km journey was scheduled to take about 7 hours. There was plenty of scenery on the way with sloping mountain ranges and deserted valleys.

Akademy 2017

Big windows encouraged sightseeing

After seven hours, I reached the Almeria railway station at 10pm. According to Google Maps, Residencia Civitas, the hostel which KDE had booked for all the attendees was only 800m away - well within walking distance. However, unbeknownst to me, I started walking in the opposite direction (my phone doesn't have a compass!). This kept increasing the Google Maps ETA and only when I was 2km off track I realised something was very wrong. Fortunately, I managed to get a taxi to take me to Residencia Civitas - a university hostel where all the Akademy attendees would be staying for the week.

After checking in to Civitas, I made my way to the double room. Judging from the baggage and the shoes in the corner, someone had moved in here before I did. About half an hour later, I found out who - Rahul Yadav, a fourth year student at DTU, Delhi. Exhausted after an eventful day of travel, I switched off the lights and went to sleep.

The Conference

The next day, I got to see other the Akademy attendees over breakfast at Civitas. In all, there were about 60-70 attendees, which I was told was slightly smaller than previous years.

The conference was held at University of Almería, located a few kilometres from the hostel. KDE had hired a public bus for transport to and from the hostel for all the days of the conference. The University was a stone's throw from the Andalusian coastline. After being seated in one of the larger lecture halls, Akademy 2017 was underway.

Akademy 2017

Konqi! And KDE Neon!

The keynote talk was by Robert Kayne of Metabrainz, about the story of how MusicBrainz was formed out of the ashes of CDDB. The talk set the tone for the first day of Akademy.

The coffee break after the first two talks was much needed. I was grappling with sleep deprivation and jet lag from the last two days and needed all the caffeine and sugar I could get to keep myself going for the rest of the day. Over coffee, I caught up with some KDE developers I met at QtCon.

Throughout the day, there were a lot of good talks, notably 'A bit on functional programming', and five quick lightning talks on a variety of topics. Soon after this, it was time for my very own talk - 'An Introduction to the KIO Library'.

The audience for my talk consisted of developers with several times my experience. Much to my delight, the maintainer of the KIO Library, David Faure was in the audience as well!

Here's where I learned another thing about giving presentations - they never quite go as well as it seems to go when rehearsed alone. I ended up speaking faster than I planned to, leaving more than enough time for a QA round. Just as I was wary about, I was asked some questions about the low-level implementation of KIO which thankfully David fielded for me. I was perspiring after the presentation, and it wasn't the temperature which was the problem 😅 A thumbs up from David afterwards gave me some confidence that I had done alright.

Following this, I enjoyed David Edmundson's talk about Binding properties in QML. The next presentation I attended after this is where things ended up getting heated. Paul Brown went into detail about everything wrong with Kirigami's TechBase page. This drew some, for lack of a better word, passionate people to retaliate. Though it was it was only supposed to be a 10 minute lightning talk, the debate raged on for half-an-hour among the two schools of thought of how TechBase documentation should be written. The only thing which brought the discussion to an end was the bus for returning to Civitas leaving sharp at 8pm.

Still having a bit of energy left after the conference, I was ready to explore this Andalusian city. One thing which worked out nicely on this trip is the late sunset in Spain around this time of the year. It is as bright as day even at around 9pm and the light only starts waning at around 930pm. This gave Rahul and me plenty of time to head to the beach, which was about a 20 minute walk from the hostel.

Here, it struck me how much I loved the way of life here.

Unlike Madrid, Almeria is not a known as a tourist destination so most of the people living there were locals. In a span of about half an hour I watched how an evening unfolds in this city. As the sun started dipping below the horizon, families with kids, college couples, and high-school friends trickled from the beach to the boardwalk for dinner. A typical evening looked delightfully simple and laid-back in this peaceful city.

The boardwalk had plenty of variety on offer - from seafood to Italian cuisine. One place caught my eye, a small cafe with Doner Kebab called 'Taj Mahal'. After a couple of days of eating nothing but bland sandwiches, Rahul and I were game for anything with a hint of spice of it. As I had done in Madrid, I tried ordering Doner Kebab using a mixture of broken Spanish and improvised sign language, only to receive a reply from the owner in Hindi! It turned out that the owner of the restaurant was Pakistani and had migrated to Spain seven years ago. Rahul made a point to ask for more chilli - and the Doner kebabs we got were not lacking in spice. I had more chilli in that one kebab than I normally would have had in a week. At least it was a change from Spanish food, which I wasn't all that fond of.

Akademy 2017

View from the boardwalk

Akademy 2017

The next day was similar to the first, only a lot more fun. I spent a lot amount of time interacting with the people from KDE India. I also got to know my GSoC mentor, Boudhayan Gupta (@BaloneyGeek). The talks for this day were as good as the ones yesterday and I got to learn about Neon Docker images, the story behind KDE's Slimbook laptop, and things to look forward to in C++17/20.

The talks were wrapped up with the Akademy Awards 2017.

Akademy 2017

David Faure and Kevin Ottens

There were still 3 hours of sunlight left after the conference and not being ones to waste it, we headed straight for the beach. Boudhayan and I made a treacherous excursion out to a rocky pier covered with moss and glistening with seawater. My well-worn sandels were the only thing keeping me from slipping onto a bunch of sharply angled stones jutting out from the waves. Against my better judgement, I managed to reach the end of the pier only to see a couple of crabs take interest in us. With the tide rising and the sun falling, we couldn't afford to stay much longer so we headed back to the beach just as we came. Not long after, I couldn't help myself and I headed into the water with enthusiasm I had only knew as a child. Probably more so for BaloneyGeek though, who headed in headfirst with his three-week-old Moto G5+ in his pocket (Spoiler: the phone was irrevocably damaged from half a minute of being immersed in saltwater). In the midst of this, we found a bunch of KDE folks hanging out on the beach with several boxes of pizza and bottles of beer. Free food!

Exhausted but exhilarated, we headed back to Civitas to end another very memorable day in Almeria.

Akademy 2017

Estacion Intermodal, a hub for public transport in Almeria

With the talks completed, Akademy 2017 moved on to its second leg, which consisted more of BoFs (Birds of a Feather) and workshops.

The QML workshop organised by Anu was timely as my relationship with QML has been hot and cold. I would always go in circles with the QML Getting Started tutorials as there aren't as many examples of how to use QtQuick 2.x as there are with say, Qt Widgets. I understood how to integrate JavaScript with the QML GUI and I will probably get around to making a project with the toolkit when I get the time. Paul Brown held a BoF about writing good user documentation and deconstructed some more pretentious descriptions of software with suggestions on how to avoid falling into the same pitfalls. I sat on a few more BoFs after this, but most of the things went over my head as I wasn't contributing to the projects discussed there.

Feeling a bit weary of the beach, Rahul and I decided to explore the inner parts of the city instead. We planned to go to the Alcazaba of Almeria, a thousand-year-old fortress in the city. On the way, we found a small froyo shop and ordered a scoop with chocolate sauce and lemon sauce. Best couple of euros spent ever! I loved the tart flavour of the froyo and how it complemented the toppings with its texture.

This gastronomic digression aside, we scaled a part of the fort only to find it locked off with a massive iron door. I got the impression that the fort was rarely ever open to begin with. With darkness fast approaching, we found ourselves in a dodgy neighbourhood and we tried to get out as fast as we could without drawing too much attention to ourselves. This brought an end to my fourth night in Almeria.

Akademy 2017

View from Alcazaba

The BoFs continued throughout the 25th, the last full day of Akademy 2017. I participated in the GSoC BoF where KDE's plans for future GSoCs, SoKs, and GCIs were discussed (isn't that a lot of acronyms!). Finally, this was one topic where I could contribute to the discussion. If there was any takeaway from the discussion for GSoC aspirants, it is to start as early as you can!

I sat on some other BoFs as well, but most of the discussed topics were out of my scope. The Mycroft and VDG BoF did have some interesting exchange of ideas for future projects that I might consider working on if I get free time in the future.

Rahul was out in the city that day, so I had the evening to explore Almeria all by myself.

I fired up Google Maps to see anything of interest nearby. To the west of the hostel was a canal I hadn't seen previously so I thought it would be worth a trip. Unfortunately, because of my poor navigation skills and phone's lack of compass, I ended up circling a flyover for a while before ditching the plan. I decided to go to the beach as a reference point and explore from there.

What was supposed to be a reference point ended up becoming the destination. There was still plenty of sunlight and the water wasn't too cold. I put one toe in the water, and then a foot.

And then, I ran.

Running barefoot alone the coastline was one of the best memories I have of the trip. For once, I didn't think twice about what I was doing. It was pure liberation. I didn't feel the exertion or the pebbles pounding my feet.

Akademy 2017

Almeria's Beaches

The end of the coastline had a small fort and a dirt trail which I would've very much wanted to cycle on. After watching the sun sink into the sea, I ran till the other end of the boardwalk to find an Italian restaurant with vegetarian spinach spaghetti. Served with a piece of freshly baked bread, dinner was delicious and capped off yet another amazing day in Almeria.

Akademy 2017

Dinner time!

Day Trip

The 26th was the final day of the conference. Unlike the other days, the conference was only for half a day with the rest of the day kept aside for a day trip. I cannot comment on how the conference went on this day as I had to rush back to the hostel to retrieve my passport, which was necessary to attend the day trip.

Right around 2 in the afternoon we boarded the bus for the day trip. Our first stop was the Plataforma Solar de Almería, a solar energy research plant in Almeria. It houses some large heliostats for focussing sunlight at a point on a tower. This can be used for heating water and producing electricity.

There was another facility used for testing the tolerance of spacecraft heat shields by subjecting them to temperatures in excess of 2000C by focussing sunlight.

Akademy 2017

Heliostats focus at the top of the tower

The next stop was at the San José village. Though not too far from Almeria, the village is frequented by tourists much more than Almeria is and has a very different vibe. The village is known for its beaches, pristine clear waters, and white buildings. I was told that the village was used in the shooting of some films such as The Good, The Bad, and The Ugly.

Akademy 2017

Our final stop for the day was at the Rodalquilar Gold Mine. Lost to time, the mine had been shut down in 1966 due to the environmental hazards of using cyanide in the process to sediment gold. The mine wouldn't have looked out of place in a video-game or an action movie, and indeed, it was used in the filming of Indiana Jones and the Last Crusade. There was a short trek from the base of the mine to a trail which wrapped around a hill. After descending from the top we headed back to the hostel.

Akademy 2017

This concluded my stay in Almeria.


After checking out of the hostel early the next morning, I caught a train to Madrid. I had a day in the city before my flight to Bangalore the next day.

I reached Atocha at about 2 in the afternoon and checked in to a hotel. I spent the entire evening exploring Madrid on foot and an electric bicycle through the BiciMAD rental service.

Photo Dump

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The Return

My flight back home was on the following morning, on the 28 July. The first leg of the return was yet again, on an Etihad aircraft bound for Abu Dhabi. This time it was an A330-300. It was an emotional 8 hour long flight - with the memories of Akademy still fresh in my mind. To top it off, I finished EarthBound (excellent game!) during the flight.

Descent into Abu Dhabi started about half an hour before landing. This time though, I got to see the bizarre Terminal 1 dome of the Abu Dhabi airport. The Middle East has always been a mystical place for me. The prices of food and drink in the terminal were hard to stomach - 500mL of water was an outrageous 8 UAE Dirhams (₹140)! Thankfully it wasn't a very long layover, so I didn't have to spend too much.

Akademy 2017

Note to self: may cause tripping if stared at for too long

The next leg was a direct flight to Bangalore, on another Etihad A330. Compared to all the travel I had done in the last two days, the four hour flight almost felt too short. I managed to finish 'Your Lie in April' on this leg.

I had mixed emotions on landing in Bangalore - I was glad to have reached home, but a bit sad that I had to return to college in only two days.

Akademy 2017 was an amazing trip and I am very grateful to KDE for letting me present at Akademy and for giving me the means of reaching there. I hope I can make more trips like these in the future!

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<![CDATA[KIO Stash - Shipped!]]>It's been almost a year since I finished my GSoC project for implementing discontinuous file selections as a KIOSlave.

The ioslave is now officially shipped in the KDE ExtraGear Utils software package and it can be downloaded from here: https://download.kde.org/stable/kio-stash/kio-stash-1.0.tar.xz.mirrorlist

http://arnavdhamija.com/2017/07/04/kio-stash-shipped/5b727033231bbd18297eafd7Tue, 04 Jul 2017 06:00:00 GMT

It's been almost a year since I finished my GSoC project for implementing discontinuous file selections as a KIOSlave.

The ioslave is now officially shipped in the KDE ExtraGear Utils software package and it can be downloaded from here: https://download.kde.org/stable/kio-stash/kio-stash-1.0.tar.xz.mirrorlist


Selecting multiple files in any file manager for copying and pasting has never been a pleasant experience, especially if the files are in a non-continuous order. Often, when selecting files using Ctrl+A or the selection tool, we find that we need to select only a subset of the required files we have selected. This leads to the unwieldy operation of removing files from our selection. Of course, the common workaround is to create a new folder and to put all the items in this folder prior to copying, but this is a very inefficient and very slow process if large files need to be copied. Moreover Ctrl+Click requires fine motor skills to not lose the entire selection of files.

This is an original project with a novel solution to this problem. My solution is to add a virtual folder in all KIO applications, where the links to files and folders can be temporarily saved for a session. The files and folders are "staged" on this virtual folder. Files can be added to this by using all the regular file management operations such as Move, Copy and Paste, or by drag and drop. Hence, complex file operations such as moving files across many devices can be made easy by staging the operation before performing it.

Project Overview

This project consists of the following modules. As there is no existing implementation in KIO for managing virtual directories, all the following modules were written completely from scratch.

KIO Slave

The KIO slave is the backbone of the project. This KIO slave is responsible for interfacing with the GUI of a KDE application and provides the methods for various operations such as copying, deleting, and renaming files. All operations on the KIO slave are applied on a virtual stash filesystem (explained below). These operations are applied through inter process communication using the Qt's D-Bus API.

The advantage of the KIO slave is that it provides a consistent experience throughout the entire KDE suite of applications. Hence, this feature would work with all KIO compatible applications.

Stash File System

The Stash File System (SFS) is used for virtually staging all the files and directories added to the ioslave. When a file is copied to the SFS, a new File Node is created to it under the folder to which it is copied. On copying a folder, a new Directory Node is created on the SFS with all the files and directories under it copied recursively as dictated by KIO. The SFS is a very important feature of the project as it allows the user to create folders and move items on the stash ioslave without touching the physical file system at all. Once a selection is curated on the ioslave, it can be seamlessly copied to the physical filesystem.

The SFS is implemented using a QHash pair of the URL as a key, containing the location of the file on the SFS and the value containing a StashNodeData object which contains all the properties (such as file name, source, children files for directories) of a given node in SFS.

Memory use of the SFS is nominal on a per file basis - each file staged on the SFS requires roughly 300 bytes of memory.

Stash Daemon

The Stash File System runs in the KDE Daemon (kded5) container process. An object of the SFS is created on startup when the daemon is initialized. The daemon responds to calls from the ioslave communicated over the session bus and creates and removes nodes in the SFS.


Make sure you have KF5 backports with all the KDE dependency libraries installed before you build!

Download the tarball to your favorite folder, extract, and run:

mkdir build
cd build
sudo make install


Open Dolphin and set the path as stash:/. This directory is completely 'virtual' and anything added to it will not consume any extra disk space. All basic file operations such as copy, paste, and move should work.

Folders can be created, curated, and renamed on this virtual folder itself. However, as this is a virtual directory, files cannot be created on it.

Copying from remote locations such as mtp:/ may not work however. Please report any bugs for the same on http://bugs.kde.org/.

<![CDATA[GSoC Report - Wrapping up GSoC 2016]]>That’s it. After a combined total of 217 git commits, 6,202 lines of code added, and 4,167 lines of code deleted, GSoC 2016 is finally over.

These twelve weeks of programming have been a very enriching experience for me and making this project has taught me a

http://arnavdhamija.com/2016/08/30/gsoc-report-wrapping-up-gsoc-2016/5b726e90231bbd18297eafcbMon, 29 Aug 2016 20:15:00 GMT

That’s it. After a combined total of 217 git commits, 6,202 lines of code added, and 4,167 lines of code deleted, GSoC 2016 is finally over.

GSoC Report - Wrapping up GSoC 2016
These twelve weeks of programming have been a very enriching experience for me and making this project has taught me a lot about production quality software development. Little did I know that a [small project](https://github.com/shortstheory/filetray-very-early-alpha-idea- thingy) I had put together in a 6 hour session of messing around with Qt would lead to something as big as this!

There have been many memorable moments throughout my coding period for the GSoC - such as the first time I got an ioslave to install correctly, to writing its “Hello World” equivalent, and getting a basic implementation of the project up and running by doing a series of dirty hacks with Dolphin’s code. There were also times when I was so frustrated with debugging for this project, that I wanted to do nothing but smash my laptop’s progressively failing display panel with the largest hammer I could find. The great mentorship from my GSoC mentor and the premise of the GSoC program itself kept me going. This also taught me an important lesson with regards to software development - no one starting out gets it right on their first try. It feels like after a long run of not quite getting the results I wanted, the GSoC is the thing which worked out for me as everything just fell into place.

There’s a technical digression here, which you can feel free to skip through if you don’t want to get into the details of the project.

Following up from the previous blog post, with the core features of the application complete, I had moved on to unit testing my project. For this project, unit testing involved writing test cases for each and every component of the application to find and fix any bugs. Despite the innocuous name, unit testing this project was a much bigger challenge than I expected. As for one thing, the ioslave in my project is merely a controller in the MVC system of the virtual Stash File System, the Dolphin file manager, and the KIO Slave itself. Besides, most of the ioslave’s functions have a void return type, so feeding the slave’s functions’ arguments to get an output for checking was not an option either.

This led me to use an approach, which my mentor aptly called “black box testing”.

In this approach, one writes unit tests testing for a specific action and then checking for whether the effects of the said action are as expected. In this case, the ioslave was tested by giving it a test file and then apply some of the ioslave’s functions such as copy, rename, delete, and stat. From there, through a bunch of QVERIFY calls is to check whether the ioslave has completed the operation successfully. Needless to say, this approach is far more convoluted to write unit tests for as it required checking each and every test file for its properties in every test case. Fortunately, the QTestLib API is pretty well documented so it wasn’t difficult to get started with writing unit tests. I also had a template of what a good test suite should look like thanks to David Faure’s excellent work on implementing automated unit testing for the Trash ioslave. With these two tools in hand, I started off with writing unit tests shortly before the second year of college started.

As expected, writing black box unit tests was a PITA in its own right. The first time I ran my unit test I came up with a dismal score of 6 unit tests passed out of the 17 I had written. This lead me to go back and check whether my unit tests were testing correctly at all. It turned out that I had made so many mistakes with writing the unit tests that an entire rewrite of the test suite wasn’t unwarranted.

With a rewrite of the test cases completed, I ran the test suite again. The results were a bit better - 13 out of the 17 test cases passed, but 4 failed test cases - enough reason for the project to be unshippable. Looking into the issue a bit deeper, I found out that all the D-Bus calls to my ioslave for copy and move operations were not working correctly! Given that I had spent so much time on making sure the ioslave was robust enough, this was a mixed surprise. Finally, after a week of rewriting and to an extent, refactoring the rename and copy functions of the ioslave, I got the best terminal output I ever wanted from this project.

GSoC Report - Wrapping up GSoC 2016

Definitely the highest point of the GSoC for me. From there on out, it was a matter of putting the code on the slow burner for cleaning up any leftover debug statements and for writing documentation for other obscure sections. With a net total of nearly 2000 lines of code, it far surpasses any other project I’ve done in terms of size and quality of code written.

At some points in the project, I felt that the stipend was far too generous, for many people working on KDE voluntarily produce projects much larger thann mine. In the end, I feel the best way to repay the generosity is to continue with open source development - just as the GSoC intended. Prior to the GSoC, open source was simply an interesting concept to me, but contributing a couple of thousands of lines of code to an open source codebase has made me realise just how powerful open source is. There were no restrictions on when I had to work (usually my productivity was at its peak at outlandish late night hours), on the machine I used for coding (a trusty IdeaPad, replaced with a much nicer ThinkPad), or on the place where I felt most comfortable coding from (a toss up between my much used study table or the living room). In many ways, working from home was probably the best environment I could ask for when it came to working on this project. Hacking on an open source project gave me a sense of gratification solving a problem in competitive programming never could have.

The Google Summer of Code may be over, but my journey with open source development has just begun. Here’s to even bigger and better projects in the future!

<![CDATA[GSoC Update: Tinkering with KIO]]>I'm a lot closer to finishing the project now. Thanks to some great support from my GSoC mentor, my project has turned out better than what I had written about in my proposal! Working together, we've made a lot of changes to the project.

For starters, we've changed the name

http://arnavdhamija.com/2016/07/21/gsoc-update-tinkering-with-kio/5b7261fc231bbd18297eafb8Thu, 21 Jul 2016 09:48:00 GMT

I'm a lot closer to finishing the project now. Thanks to some great support from my GSoC mentor, my project has turned out better than what I had written about in my proposal! Working together, we've made a lot of changes to the project.

For starters, we've changed the name of the ioslave from "File Tray" to "staging" to "stash". I wasn't a big fan of the name change, but I see the utility in shaving off a couple of characters in the name of what I hope will be a widely used feature.

Secondly, the ioslave is now completely independent from Dolphin, or any KIO application for that matter. This means it works exactly the same way across the entire suite of KIO apps. Given that at one point we were planning to make the ioslave fully functional only with Dolphin, this is a major plus point for the project.

Next, the backend for storing stashed files and folders has undergone a complete overhaul. The first iteration of the project stored files and folders by saving the URLs of stashed items in a QList in a custom "stash" daemon running on top of kded5. Although this was a neat little solution which worked well for most intents and purposes, it had some disadvantages. For one, you couldn't delete and move files around on the ioslave without affecting the source because they were all linked to their original directories. Moreover, with the way 'mkdir' works in KIO, this solution would never work without each application being specially configured to use the ioslave which would entail a lot of groundwork laying out QDBus calls to the stash daemon. With these problems looming large, somewhere around the midterm evaluation week, I got a message from my mentor about ramping up the project using a "StashFileSystem", a virtual file system in Qt that he had written just for this project.

The virtual file system is a clever way to approach this - as it solved both of the problems with the previous approach right off the bat - mkdir could be mapped to virtual directory and now making volatile edits to folders is possible without touching the source directory. It did have its drawbacks too - as it needed to stage every file in the source directory, it would require a lot more memory than the previous approach. Plus, it would still be at the whims of kded5 if a contained process went bad and crashed the daemon.

Nevertheless, the benefits in this case far outweighed the potential cons and I got to implementing it in my ioslave and stash daemon. Using this virtual file system also meant remapping all the SlaveBase functions to corresponding calls to the stash daemon which was a complete rewrite of my code. For instance, my GitHub log for the week of implementing the virtual file system showed a sombre 449++/419--. This isn't to say it wasn't productive though - to my surprise the virtual file system actually worked better than I hoped it would! Memory utilisation is low at a nominal ~300 bytes per stashed file and the performance in my manual testing has been looking pretty good.

With the ioslave and other modules of the application largely completed, the current phase of the project involves integrating the feature neatly with Dolphin and for writing a couple of unit tests along the way. I'm looking forward to a good finish with this project.

You can find the source for it here: https://github.com/KDE/kio-stash (did I mention it's now hosted on a [KDE repo](https://quickgit.kde.org/?p=kio- stash.git)? ;) )

<![CDATA[GSoC Update(?): Writing a KIO slave 101!]]>This project has been going well. Though it was expectedly difficult in the beginning, I feel like I am on the other side of the learning curve now. I will probably make a proper update post sometime later this month. My repo for this project can be found here: https:

http://arnavdhamija.com/2016/06/21/gsoc-update-writing-a-kio-slave-101/5b7260d7231bbd18297eafb3Tue, 21 Jun 2016 18:05:00 GMT

This project has been going well. Though it was expectedly difficult in the beginning, I feel like I am on the other side of the learning curve now. I will probably make a proper update post sometime later this month. My repo for this project can be found here: https://github.com/shortstheory/kio-stash

For now, this is a small tutorial for writing KDE I/O slaves (KIO slaves) which can be used for a variety of KDE applications. KIO slaves are a great way for accessing files from different filesystems and protocols in a neat, uniform way across many KDE applications. Their versatility makes them integral to the KIO library. KIO slaves have changed in their structure the transition to KF5 and this tutorial highlights some of these differences from preceding iterations of it.

Project Structure

For the purpose of this tutorial, your project source directory needs to have the following files.

  • kio_hello.h
  • kio_hello.cpp
  • hello.json
  • CMakeLists.txt

If you don't feel like creating these yourself, just clone it from here: https://github.com/shortstheory/kioslave-tutorial


The .json file replaces the .protocol files used in KIO slaves pre KF5. The .json file for the KIO slave specifies the properties the KIO slave will have such as the executable path to the KIO slave on installation. The .json file also includes properties of the slave such as being able to read from, write to, delete from, among many others. Fields in this .json file are specified from the [KProtocolManager](https://api.kde.org/frameworks/kio/html/classKProt ocolManager.html) class. For creating a KIO slave capable of showing a directory in a file manager such as Dolphin, the listing property must be set to true. As an example, the .json file for the Hello KIO slave described in this tutorial looks like this:

    "KDE-KIO-Protocols" : {   
        "hello": {   
            "Class": ":local",   
            "X-DocPath": "kioslave5/kio_hello.html",   
            "exec": "kf5/kio/hello",   
            "input": "none",   
            "output": "filesystem",   
            "protocol": "hello",   
            "reading": true   

As for the CMakeLists.txt, you will need to link your KIO slave module with KF5::KIOCore. This can be seen in the project directory.


#ifndef HELLO_H  
#define HELLO_H  

#include <kio/slavebase.h>  

  This class implements a Hello World kioslave  
class Hello : public QObject, public KIO::SlaveBase  
    Hello(const QByteArray &pool, const QByteArray &app);   
    void get(const QUrl &url) Q_DECL_OVERRIDE;   


The Hello KIO slave is derived from KIO::SlaveBase. The SlaveBase class has some basic functions already implemented for the KIO slave. This can be found in the [documentation](https://api.kde.org/frameworks/kio/html/classKIO_1_1Sla veBase.html). However, most of the functions of SlaveBase are virtual functions and have to be re-implemented for the KIO slave. In this case, we are re-implementing the get function to print a QString when it is called by kioclient5.

In case you don't need special handling of the KIO slave's functions, you can derive your KIO slave class directly from [KIO::ForwardingSlaveBase](https://a pi.kde.org/frameworks/kio/html/classKIO_1_1ForwardingSlaveBase.html). Here, you would only need to re-implement the rewriteUrl function to get your KIO slave working.


#include "hello.h"  
#include <QDebug>  

class KIOPluginForMetaData : public QObject  
    Q_PLUGIN_METADATA(IID "org.kde.kio.slave.hello" FILE "hello.json")   

extern "C"  
    int Q_DECL_EXPORT kdemain(int argc, char **argv)   
        qDebug() << "Launching KIO slave.";   
        if (argc != 4) {   
            fprintf(stderr, "Usage: kio_hello protocol domain-socket1 domain-socket2\n");   
        Hello slave(argv[2], argv[3]);   
        return 0;   

void Hello::get(const QUrl &url)  
    qDebug() << "Entering function.";   
    QByteArray str("Hello world!\n");   
    qDebug() << "Leaving function";   

Hello::Hello(const QByteArray &pool, const QByteArray &app)  
    : SlaveBase("hello", pool, app) {}   

#include "hello.moc"  

The .moc file is, of course, auto-generated at compilation time.

As mentioned earlier, the KIO Slave's .cpp file will also require a new KIOPluginForMetaData class to add the .json file. The following is used for the hello KIO slave and can be used as an example:

class KIOPluginForMetaData : public QObject  
    Q_PLUGIN_METADATA(IID "org.kde.kio.slave.hello" FILE "hello.json")   


cmake_minimum_required(VERSION 3.5)  
set(QT_MIN_VERSION "5.4.0")  
set(KF5_MIN_VERSION "5.16.0")  


include(KDECompilerSettings NO_POLICY_SCOPE)  
add_library(kio_hello MODULE hello.cpp)  
find_package(KF5 ${KF5_MIN_VERSION} REQUIRED KIO)  
target_link_libraries(kio_hello KF5::KIOCore)  
set_target_properties(kio_hello PROPERTIES OUTPUT_NAME "hello")  

install(TARGETS kio_hello DESTINATION ${KDE_INSTALL_PLUGINDIR}/kf5/kio )  


Simply run the following commands in the source folder:

mkdir build  
cd build  
sudo make install  

As shown above, we have to run kdeinit5 again so the new KIO slave is discovered by KLauncher and can be loaded when we run a command through an application such as kioclient5.


kioclient5 'cat' 'hello:/'  

And the output should be:

<![CDATA[GSoC Update 1: The Beginning]]>I have officially started my GSoC project under the mentorship of Boudhayan Gupta and Pinak Ahuja.

The project idea's implementation has undergone some changes from what I proposed. While the essence of the project is the same, it will now no longer be dependent on Baloo and xattr. Instead, it

http://arnavdhamija.com/2016/05/30/gsoc-update-1-the-beginning/5b725e6f231bbd18297eafaeMon, 30 May 2016 05:07:00 GMT

I have officially started my GSoC project under the mentorship of Boudhayan Gupta and Pinak Ahuja.

The project idea's implementation has undergone some changes from what I proposed. While the essence of the project is the same, it will now no longer be dependent on Baloo and xattr. Instead, it will use a QList to hold a list of staged files with a plugin to kiod. My next milestone before the mid-term evaluation is to implement this in a KIO slave which will be compatible with the whole suite of KDE applications.

For the last two weeks, I've been busy with going through hundreds of lines of source code to understand the concept of a KIO slave. The KIO API is a very neat feature of KDE - it provides a single, consistent way to access remote and local filesystems. This is further expanded to KIO slaves which are programs based on the KIO API which allow for a filesystem to be expressed in a particular way. For instance, there is a KIO slave for displaying xattr file tags as a directory under which each file marked to a tag would be displayed. KIO slaves even expand to network protocols allowing for remote access using slaves such as http:/, ftp:/, smb:/ (for Windows samba shares), fish:/, sftp:/, nfs:/, and webdav:/. My project requires virtual folder constructed of URLs stored in a QList - an ideal fit for KIO slaves.

However, hacking on KIO slaves was not exactly straightforward. Prior to my GSoC selection, I had no idea on how to edit CMakeLists.txt files and it was a task to learn to make one by hand. Initially, it felt like installing the dependencies for building KIO slaves would almost certainly lead to me destroying my KDE installation, and sure enough, I did manage to ruin my installation. Most annoying. Fortunately, I managed to recover my data and with a fresh install of Kubuntu 16.04 with all the required KDE packages, I got back to working on getting the technical equivalent of a Hello World to work with a KIO slave.

This too, was more than a matter of just copying and pasting lines of code from the [KDE tutorial](https://techbase.kde.org/Development/Tutorials/KIO_Sla ves/Hello_World). KIO slaves had dropped the use of .protocol files in the KF5 transition, instead opting for JSON files to store the properties of the KIO slave. Thankfully, I had the assistance of the legendary David Faure. Under his guidance, I managed to port the KIO slave in the tutorial to a KF5 compatible KIO slave and after a full week of frustration of dealing with dependency hell, I saw the best Hello World I could ever hope for:

GSoC Update 1: The Beginning

Baby steps. The next step was to make the KIO slave capable of displaying the contents of a specified QUrl in a file manager. The documentation for KProtocolManager made it seem like a pretty straightforward task - apparently that all I needed to do was to add a "listing" entry in my JSON protocol file and I would have to re-implement the listDir method inherited from SlaveBase using a call to SlaveBase::listDir(&QUrl). Unbeknownst to me, the SlaveBase class actually didn't have any code for displaying a directory! The SlaveBase class was only for reimplementing its member functions in a derived class as I found out by going through the source code of the core of kio/core. Learning from my mistake here I switched to using a ForwardingSlaveBase class for my KIO slave which instantly solved my problems of displaying a directory.

GSoC Update 1: The Beginning


According to my timeline, the next steps in the project are

  1. Finishing off the KIO slave by the end of this month
  2. Making GUI modifications in Dolphin to accommodate the staging area
  3. Thinking of a better name for this feature?

So far, it's been a great experience to get so much support from the KDE community. Here's to another two and a half months of KDE development!

<![CDATA[It has happened - GSoC 2016 Selection!]]>Wow!


I have been selected for the Google Summer of Code!

For the better part of the summer vacation, I will now be committing myself to write code for KDE to implement my project idea of implementing a virtual folder in Dolphin to make it easier to select files.


http://arnavdhamija.com/2016/04/23/it-has-happened-gsoc-2016-selection/5b72595c231bbd18297eafaaSat, 23 Apr 2016 06:58:00 GMT


It has happened - GSoC 2016 Selection!

I have been selected for the Google Summer of Code!

For the better part of the summer vacation, I will now be committing myself to write code for KDE to implement my project idea of implementing a virtual folder in Dolphin to make it easier to select files.

As a primer, the Google Summer of Code (GSoC) is an annual event organized by Google for drawing students to work on open source projects with a nice stipend, goodies, and fame. The GSoC is a term one would hear pretty frequently when talking about the technical prowess and coding culture of a college.

This year, BITS Pilani - Hyderabad Campus had a record number of a total of 7 selections! This is more than double of our previous record. This in some ways, might be the start of the technical culture wave this campus was looking for so long.

The File Tray idea for the GSoC came at a difficult time, hardly a month after the entrance exams in 2015. It was at a time I was frustrated with everything I had done and I didn't have any energy to pursue anything at all having been completely drained out by the entrance exams prior to it. From there, the project sat on the list of "Things I Might Do In The Distant Future". The project idea was known only to a few close friends and my tiny programming diary.

It was only till November 2015 when I stumbled across the GSoC. I began looking at open source file managers for which I could implement my project idea. I had been using Linux with various desktop environments for about 4 years at that point, so I had a pretty decent idea of what to look for. Writing this feature for GNOME's Nautilus was the first thing I looked into as I had been using Nautilus for a while and I was a big fan of Nautilus's simple to use interface. But, the problem was that Nautilus was a C/GTK+ project and I had no desire to move on to using C after having C++ in my comfort zone for a very long time. Fortunately, Dolphin, one of the best file managers I had used since my days of using KDE, used C++/Qt, a toolset I am much better with. I felt my project idea was a natural fit for Dolphin's Split view mode. KDE also had an excellent record in the GSoC with a very good number of slots and a high percentage of successful projects. This began my tryst with Open Source development.

From there on, I taught myself Qt and during a Diwali vacation on campus, I managed to make a very rough prototype application of my project after coding for 6 hours straight from 11pm to 5am the next day. Following this, I subscribed to KDE's mailing lists and after lurking around for a while, I started asking for feedback on my GSoC idea. With surprisingly positive feedback from numerous KDE developers, I realized that there might just be a non-zero chance of getting selected.

Things quickly began falling into place and I then moved on to the next step of hunting around for bugs I could fix and new features I could implement for Dolphin. The bug-fixing was as enjoyable as it was occasionally frustrating. Reading over 20000 lines of code certainly took its toll when I had no idea when how different parts of the application meshed together. In the end, thanks to the guidance of Dolphin maintainer, Emmanuel Pescosta, I managed to fix a couple of things for Dolphin and moved on to the next step of making a proposal for my GSoC application.

Starting off with making a competent proposal was like launching off ground zero as there were very few people who had successfully completed the GSoC from our campus and most of these people had graduated well before this time. I started digging around for proposals accepted by KDE in previous GSoC's. What I couldn't get from all the proposals was some sound advice from seniors. In particular, Naveen Jafer bhaiya (who also went on to achieve a GSoC project of his own!) helped me with making my proposal as good as possible. In the end, after painstakingly checking every word in my proposal for what felt like the fiftieth time I submitted it on 25 March, only to spend an anxious month waiting for the results which came out at 1230am IST on April 23. While it still hasn't sunk in yet (!), I am sure that this will make for an awesome summer vacation!

<![CDATA[GSoC 2016 Project Survey, help me make Dolphin a better File Manager!]]>Hey everyone!

I am a first year computer science undergraduate from BITS Pilani, Hyderabad Campus. I am looking forward to working for KDE for the GSoC.

My project idea is based on solving a problem all file managers have had for years - the lack of an easy to use

http://arnavdhamija.com/2016/02/15/gsoc-2016-project-survey-help-me-make-dolphin-a-better-file-manager/5b7257a3231bbd18297eaf9dMon, 15 Feb 2016 15:46:00 GMTHey everyone!

I am a first year computer science undergraduate from BITS Pilani, Hyderabad Campus. I am looking forward to working for KDE for the GSoC.

My project idea is based on solving a problem all file managers have had for years - the lack of an easy to use file selection tool. My project aims to simplify selecting files from multiple directory trees.

I am running a survey to gauge community feedback on my idea and to finalize the user interface and features list.

The link to my idea proposal can be found here: https://goo.gl/1Nj4SY

And the link to my survey can be found here: https://goo.gl/forms/5JSZXNganX

TIA for the feedback : )