Development

With a variety of new tools and features announced at Android Dev Summit, special attention should be given to the In-App Updates (IAUs) API allowing developers to increase the speed of delivering features, bug-fixes and performance improvements to active users. Since this feature was finally released after Google I/O 2019, in this article I’ll deep dive on IAUs API, describe in details recommended user flows and provide with some code samples. Moreover, I'll share some experience of IAUs integration in the Pandao app, a marketplace platform for Chinese goods.

Everyone uniquely perceives texts, regardless of whether this person reads news on the Internet or world-known classic novels. This also applies to a variety of algorithms and machine learning techniques, which understand texts in a more mathematical way, namely, using high-dimensional vector space.

This article is devoted to visualizing high-dimensional Word2Vec word embeddings using t-SNE. The visualization can be useful to understand how Word2Vec works and how to interpret relations between vectors captured from your texts before using them in neural networks or other machine learning algorithms. As training data, we will use articles from Google News and classical literary works by Leo Tolstoy, the Russian writer who is regarded as one of the greatest authors of all time.

We go through the brief overview of t-SNE algorithm, then move to word embeddings calculation using Word2Vec, and finally, proceed to word vectors visualization with t-SNE in 2D and 3D space. We will write our scripts in Python using Jupyter Notebook.

It's been two years since we last checked the code of the LLVM project with PVS-Studio, so let's see if PVS-Studio is still the leader among tools for detecting bugs and security weaknesses. We'll do that by scanning the LLVM 8.0.0 release for new bugs.

You must have already guessed from the title that today's article will be focusing on bugs in software source code. But not only that. If you are not only interested in C++ and in reading about bugs in other developers' code but also dig unusual video games and wonder what «roguelikes» are and how you play them, then welcome to read on!

Once in a while we go back to the projects that we have previously checked using PVS-Studio, which results in their descriptions in various articles. Two reasons make these comebacks exciting for us. Firstly, the opportunity to assess the progress of our analyzer. Secondly, monitoring the feedback of the project's authors to our article and the report of errors, which we usually provide them with. Of course, errors can be corrected without our participation. However, it is always nice when our efforts help to make a project better. Roslyn was no exception. The previous article about this project check dates back to December 23, 2015. It's quite a long time, in the view of the progress that our analyzer has made since that time. Since the C# core of the PVS-Studio analyzer is based on Roslyn, it gives us additional interest in this project. As a result, we're as keen as mustard about the code quality of this project. Now let's test it once again and find out some new and interesting issues (but let's hope that nothing significant) that PVS-Studio will be able to find.

The PVS-Studio team has been keeping the blog about the checks of open-source projects by the same-name static code analyzer for many years. To date, more than 300 projects have been checked, the base of errors contains more than 12000 cases. Initially the analyzer was implemented for checking C and C++ code, support of C# was added later. Therefore, from all checked projects the majority (> 80%) accounts for C and C++. Quite recently Java was added to the list of supported languages, which means that there is now a whole new open world for PVS-Studio, so it's time to complement the base with errors from Java projects.

The Java world is vast and varied, so one doesn't even know where to look first when choosing a project to test the new analyzer. Ultimately, the choice fell on the full-text search and analytical engine Elasticsearch. It is quite a successful project, and it's even especially pleasant to find errors in significant projects. So, what defects did PVS-Studio for Java manage to detect? Further talk will be right about the results of the check.

Static analysis methodology involves various technologies. One of them is preprocessing files right before analyzing them. Preprocessed files are created by the compiler that runs in a special working mode. Unfortunately, our long-standing experience of developing a static analyzer shows that this mode is not great for testing. In this note, I'll give the example of a fresh bug in the C++ compiler from Microsoft.

As many of our readers know, Qrator.Radar is constantly researching global BGP connectivity, as well as regional. Since the Internet stands for “Interconnected Networks,” to ensure the best possible quality and speed the interconnectivity of individual networks should be rich and diverse, with their growth motivated on a sound competitive basis.

The fault-resistance of an internet connection in any given region or country is tied to the number of alternate routes between ASes. Though, as we stated before in our Internet Segments Reliability reports, some paths are obviously more critical compared to the others (for example, the paths to the Tier-1 transit ISPs or autonomous systems hosting authoritative DNS servers), which means that having as many reachable routes as possible is the only viable way to ensure adequate system scalability, stability and robustness.

This time, we are going to have a closer look at the Russian Federation internet segment. There are reasons to keep an eye on that segment: according to the numbers provided by the RIPE database, there are 6183 autonomous systems in Russia, out of 88664 registered worldwide, which stands for 6.87% of total.

This percentage puts Russia on a second place in the world, right after the USA (30.08% of registered ASes) and before Brazil, owning 6.34% of all autonomous systems. Effects of changes in the Russian connectivity could be observed across many other countries dependant on or adjacent to that connectivity, and ultimately by almost any ISP in the world.

Here we are, continuing to explore the code of calculators! Today we are going to take a look at the project called SpeedCrunch, the second most popular free calculator.

Introduction

SpeedCrunch is a high-precision scientific calculator featuring a fast, keyboard-driven user interface. It is free and open-source software, licensed under the GPL and running on Windows, Linux, and macOS.

The source code is available on BitBucket. I was somewhat disappointed by the build documentation, which could be more detailed. It says that you need «Qt 5.2 or later» to build the project, but it actually required a few specific packages, which wasn't easy to figure out from the CMake log. By the way, it is considered a good practice nowadays to include a Dockerfile into the project to make it easier for the user to set up the development environment.

A completely routine tech support ticket has uncovered unexpected bans of IP addresses of Protonmail — a very useful service for people valuing their Internet freedoms — in several regions of Russia. I seriously didn’t want to sensationalize the headline, but the story is so strange and inexplicable I couldn’t resist.

TL;DR

Disclaimer: the situation is still developing. There might not be anything malicious, but most likely there is. I will update the post once new information comes through.

MTS and Rostelecom — two of the biggest Russian ISPs — started to block traffic to SMTP servers of the encrypted email service Protonmail according to an FSB request, with no regard for the official government registry of restricted websites. It seems like it’s been happening for a while, but no one paid special attention to it. Until now.

All involved parties have received relevant requests for information which they’re obligated to reply.

UPD: MTS has provided a scan of the FSB letter, which is the basis for restricting the access. Justification: the ongoing Universiade in Krasnoyarsk and “phone terrorism”. It’s supposed to prevent ProtonMail emails from going to emergency addresses of security services and schools.

UPD: Protonmail was surprised by “these strange Russians” and their methods for battling fraud abuse, as well as suggested a more effective way to do it — via abuse mailbox.

UPD: FSB’s justification doesn’t appear to be true: the bans broke ProtonMail’s incoming mail, rather than outgoing.

UPD: Protonmail shrugged and changed the IP addresses of their MXs taking them out of the blocking after that particular FSB letter. What will happen next is open ended question.

UPD: Apparently, such letter was not the only one and there is still a set of IP addresses of VOIP-services which are blocked without appropriate records in the official registry of restricted websites.

When React.js 16.8 was released we got the opportunity to use React Hooks. Hooks make us able to write fully-functional components using functions. We can use all React.js features and do in in more convenient way.

A lot of people don't agree with Hooks conception. In this article I'd like to tell about some important advantages React Hooks give you and why we need to write with Hooks.

I will not talk about how to use hooks. It is not very important for the examples. If you want to read something on this topic, you can use official documentation. Also, if this topic will be interesting for you, I will write more about Hooks.

A few days ago, Microsoft made the source code of their Windows Calculator publicly available. Calculator is an application that has traditionally shipped with every Windows version. A number of Microsoft projects went open-source over the recent years, but this time the news was covered even by non-IT media on the very first day. Well, it's a popular yet tiny program in C++. Despite its size, we still managed to find a number of suspicious fragments in its code using the PVS-Studio static analyzer.

RUVDS together with Habr.com continues the series of interviews with interesting people in computer field. Previously we met Boris Yangel, who heads AI development of Yandex’s Alice voice assistant.

Today we bring you an interview with Richard (Levelord) Gray — level designer of such legendary games as Duke Nukem, American McGee Alice, Heavy Metal F.A.K.K.2, SiN, and Serious Sam. And he is the one who coined the famous phrase «You are not supposed to be here». Richard was born and spent most of his life in USA, but several years ago he moved to Moscow to his russian wife and daughter.

These who speak to Richard are Nick Zemlyanskiy, editor of Habr.com, and Nikita Tsaplin, co-founder and managing partner of RUVDS company.


→ Text and video in Russian

TL;DR

Using a custom build script in Node JS, it is possible to manipulate a series of Sketch files, and then, using an internal Sketch tool, automatically export their assets, to generate multiple icon libraries, for multiple platforms and different brands, that support dynamic colourisation of the assets via design tokens, and also AB testing of the assets via naming convention. Easy peasy :)

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Well, actually it’s not that easy, but it can certainly be done. This post is a detailed explanation of how we did it, and what we discovered along the way.

The problem we were trying to solve

At Badoo we build a dating app. Actually, multiple dating apps. For multiple platforms (iOS, Android, Mobile Web, Desktop Web), across multiple teams.

We use hundreds of icons in our apps. Some of them are the same across different apps, some are very specific to the brands the apps reflect. The icons are continuously evolving, in sync with the evolution of the design. Sometimes completely new icons are added, while others get updated, and still others get dropped (although, they often remain in the codebase).

The Object base type and implementation of interfaces. Boxing

It seems we came through hell and high water and can nail any interview, even the one for .NET CLR team. However, let's not rush to microsoft.com and search for vacancies. Now, we need to understand how value types inherit an object if they contain neither a reference to SyncBlockIndex, not a pointer to a virtual methods table. This will completely explain our system of types and all pieces of a puzzle will find their places. However, we will need more than one sentence.

Now, let's remember again how value types are allocated in memory. They get the place in memory right where they are. Reference types get allocation on the heap of small and large objects. They always give a reference to the place on the heap where the object is. Each value type has such methods as ToString, Equals and GetHashCode. They are virtual and overridable, but don’t allow to inherit a value type by overriding methods. If value types used overridable methods, they would need a virtual methods table to route calls. This would lead to the problems of passing structures to unmanaged world: extra fields would go there. As a result, there are descriptions of value type methods somewhere, but you cannot access them directly via a virtual methods table.

This may bring the idea that the lack of inheritance is artificial

This chapter was translated from Russian jointly by author and by professional translators. You can help us with translation from Russian or English into any other language, primarily into Chinese or German.

Also, if you want thank us, the best way you can do that is to give us a star on github or to fork repository github/sidristij/dotnetbook.

Vue mixins are the recommended way of sharing common functionality between components. They are perfectly fine until you use more than one for them. That's because they are implicit by design and pollute your component's context. Let's try to fix this by giving them as much explicitness as we can.

Hi everyone!

Winter has arrived, and so I had to check the thermal insulation of my out of town residence dacha. And it just turned out a famous Chinese marketplace started to sell cheap thermal camera modules. So I decided to DIY it up and build a rather exotic and useful thing — a heat visor for the home. Why not? Especially since I had a Raspberry Pi lying around anyway… The result is down below.

I once had a discussion with a founder of an Israeli startup developing a GPU-based database with a focus on speed. The work stack included Haskell and C++, among others, and the founder was complaining about how hard it is to find competent programmers. Which was part of the reason he came to Moscow.

I carefully asked if they considered using something more popular and new. And even though the answer was rather polite and well-supported with arguments, it still sounded like “Come on, don’t even bring up these toys”.

Until then, all I heard about Haskell could be summarized as “be VERY careful in dealing with it”. To get to know Haskell programmers better, I came to a topical Telegram chat with some questions. I was quite afraid at first, and, as it turned out, I was right.

Haskell doesn’t lend itself to popular explanation, and people seemingly don’t even try. If the topic is ever brought up, it’s only talked about in full depth and as objectively as possible. Someone wrote to me: “One of the defining features of both Haskell itself and its community is that they didn’t try to achieve any kind of mainstream recognition. Instead, they focused on building a logical, principal way of solving real problems over trying to appease the widest audience possible”

Nevertheless, a couple of people did tell me about their experiences, which are shown below.

Pathfinder: Kingmaker (PF:K for short) is a role-playing video game created by Owlcat Games, released in Fall 2018 on Steam and GoG. Inspired by classic Bioware games, this project uses a popular board game system ruleset, combat takes place in Real-Time with Pause, follows an isometric camera, and has a non-linear story with multiple unique endings.

In this article, I will share a little about how we worked on designing the audio throughout the game’s development including task management, the search for inspiration, and troubleshooting. An experienced specialist may not find anything particularly groundbreaking in this recap, but beginners and enthusiasts will definitely discover some points of interest.

A few months ago I came across a very interesting documentary series on Netflix called Abstract, they basically explore the output of professional designers from different sectors like architecture, graphic design, fashion, … in their workplaces.

It was easy to spot some similarities in the work of designers from other fields with that of an iOS developer who implements user interfaces. For example, when a designer is creating something that is big enough to be broken down into smaller parts, using a strategy like ‘Divide and Conquer’ is key to being able to focus on smaller parts that will be assembled at later stages in the process.

Breaking down a whole design into smaller subunits allows us to think about each problem in isolation, removing any dependencies between the components. But the full picture also needs to be present throughout the whole process, otherwise there can be problems when the time comes to fit everything back together.

On the other hand, while watching Abstract I noticed that in the design process for objects like a shoes, banners or buildings the final design remains fixed for the lifetime of the product. The design of a Nike shoe isn’t going to change after it is released and there aren’t going to be any updates once it’s on the shelf in the shop. Sometimes a design remains unchanged even 20 years later, and the product is still sound.