Antonio Soares de Azevedo Terceiro

A Study of the Relationships between Source Code Metrics and Attractiveness in Free Software Projects

A significant number of Free Software projects has been widely used and considered successful. However, there is an even larger number of them that cannot overcome the initial step towards building an active community of users and developers. In this study, we investigated whether there are relationships between source code metrics and attractiveness, i.e., the ability of a project to attract users and developers. To verify these relationships, we analyzed 6,773 Free Software projects from the SourceForge.net repository. The results indicated that attractiveness is indeed correlated to some source code metrics. This suggests that measurable attributes of the project source code somehow affect the decision to contribute and adopt a Free Software project. The findings described in this study show that it is relevant for project leaders to monitor source code quality, most specifically a few objective metrics, since these can have a positive influence in their chances of forming a community of contributors and users around the software, enabling further enhancement in its quality.

An Empirical Study on the Structural Complexity Introduced by Core and Peripheral Developers in Free Software Projects

Background: Several factors may impact the process of software maintenance and evolution of free software projects, including structural complexity and lack of control over its contributors. Structural complexity, an architectural concern, makes software projects more difficult to understand, and consequently more difficult to maintain and evolve. The contributors in a free software project exhibit different levels of participation in the project, and can be categorized as core and peripheral developers. Research aim: This research aims at characterising the changes made to the source code of 7 web server projects written in C with respect to the amount of structural complexity added or removed and the developer level of participation. Method: We performed a observational study with historical data collected from the version control repositories of those projects, recording structural complexity information for each change as well as identifying each change as performed by a core or a peripheral developer. Results and conclusions: We have found that core developers introduce less structural complexity than peripheral developers in general, and that in the case of complexity-reducing activities, core developers remove more structural complexity than peripheral developers. These results demonstrate the importance of having a stable and healthy core team to the sustainability of free software projects.

Free and Open Source Software Development and Research: Opportunities for Software Engineering

Free/Libre/Open Source Software (FLOSS) communities have produced a large amount of valuable software that is directly or indirectly used daily by any person with access to a computer. The field of Software Engineering studies processes, mechanisms, tools, and frameworks for the development of software artifacts. Historically, however, most of Software Engineering research and education does not benefit from the large and rich source of data and experimental testbeds offered by FLOSS projects and their hundreds of millions of lines of working code. In this paper, we discuss how Software Engineering research and education can greatly benefit from the wealth of information available in the FLOSS ecosystem. We then evaluate how FLOSS has been used, up to now, by papers published in the Brazilian Symposium on Software Engineering. Finally, we present an agenda for the future, proposing concrete ways to exploit the synergies between research and education in Software Engineering and FLOSS projects.

Understanding Structural Complexity Evolution: A Quantitative Analysis

Background: An increase in structural complexity makes the source code of software projects more difficult to understand, and consequently more difficult and expensive to maintain and evolve. Knowing the factors that influence structural complexity helps developers to avoid the effects of higher levels of structural complexity on the maintainability of their projects. Aims: This paper investigates factors that might influence the evolution of structural complexity. Method: We analyzed the source code repositories of 5 free/open source software projects, with commits as experimental units. For each commit we measured the structural complexity variation it caused, the experience of the developer who made the commit, the size variation caused by the commit, and the change diffusion of the commit. Commits that increased structural complexity were analyzed separately from commits that decreased structural complexity, since they represent activities of distinct natures. Results: Change diffusion was the most influential among the factors studied, followed by size variation and developer experience, system growth was not necessarily associated with complexity increase, all the factors we studied influenced at least two projects, different projects were affected by different factors, and the factors that influenced the increase in structural complexity were usually not the same that influenced the decrease. Conclusions: All the factors explored in this study should be taken into consideration when analysing structural complexity evolution. However, they do not fully explain the structural complexity evolution in the studied projects: this suggests that qualitative studies are needed in order to better understand structural complexity evolution and identify other factors that must be included in future quantitative analysis.

Brazilian Public Software Portal: an integrated platform for collaborative development

The Brazilian Public Software (SPB) is a program promoted by the Brazilian Federal Government to foster sharing and collaboration on Free/Libre/Open Source Software (FLOSS) solutions for the public administration. In this context, a public software is considered a public good and the Federal Government assumes some responsibilities related to its use. Once its devolpment principles is the same of the FLOSS projects, we have designed the SPB Portal, a platform based on the integration and evolution of existing FLOSS tools. It provides several modern features for software collaborative development, helping the Brazilian public administration in sharing its solutions. In this paper, we present this integrated software development platform that was developed for the SPB program by a heterogeneous team composed by professors, master students and undergraduate students, as well as by professionals from FLOSS communities. The development of this platform used several FLOSS projects, providing a non-trivial integration among them. This effort has also produced several new features that were contributed back to these projects. Alongside the architectural challenges, we also discuss in this paper our work process, based on agile and free software development practices, and the lessons learned during 30 months of work on the SPB project.

Implementing Federated Social Networking: Report from the Trenches

The federation of social networks aims at integrating users by means of a decentralized structure, enabling the interoperability among multiple social networks in a transparent way. Despite a few isolated initiatives in federating open social networks, there is no adoption of any standard, which hinders the emergence of new, effective federated systems. To understand the difficulties in the development and standardization of federated services, we have conducted research on existing specifications and implementations of interoperability among social networks. We have developed a federation proof of concept within the Noosfero platform, implementing a subset of the Diaspora protocol to federate users and public content, in addition to complementary specifications, such as Salmon and WebFinger. In this work, we introduce our results to federate Noosfero with Diaspora networks, pointing the required steps before further development. We aim to implement the Diaspora protocol within Noosfero, finishing its specification and improving its documentation, encouraging more projects to adopt this protocol.

A study on low complexity models to predict flaws in the Linux source code

Due to the constant evolution of technology, each day brings new programming languages, development paradigms, and ways of evaluating processes. This is no different with source code metrics, where there is always new metric classes. To use a software metric to support decisions, it is necessary to understand how to perform the metric collection, calculation, interpretation, and analysis. The tasks of collecting and calculating source code metrics are most often automated, but how should we monitor them during the software development cycle? Our research aims to assist the software engineer to monitor metrics of vulnerability threats present in the source code through a reference prediction model, considering that real world software have non-functional security requirements, which implies the need to know how to monitor these requirements during the software development cycle. As a first result, this paper presents an empirical study on the evolution of the Linux project. Based on static analysis data, we propose low complexity models to study flaws in the Linux source code. About 391 versions of the project were analyzed by mining the official Linux repository using an approach that can be reproduced to perform similar studies. Our results show that it is possible to predict the number of warnings triggered by a static analyzer for a given software project revision as long as the software is continuously monitored.

Patterns for engagement in free software projects

Free/Libre/Open Source Software (FLOSS) projects are developed in a collaborative manner, by communities of contributors that work on publicly available source code. However, many potential contributors are still daunted by the FLOSS world. The Patterns for Engagement in Free Software Projects present solutions for recurring problems that emerge when prospective contributors are willing to select a FLOSS project to get involved and to contribute with. They are organized around three clusters: (a) Selection Patterns, that help prospective contributors to find suitable projects, (b) Involvement Patterns, that deal with the first steps towards getting familiar and involved with the selected project, and (c) Contribution Patterns, that document best practices for submitting different kinds of contribution to a free software project. The Patterns for Engagement in Free Software Projects catalog is itself a FLOSS project. Its license allows free reuse of the text, as long as the modified versions are distributed under the same license.

Issues on building T++: a tool for web application development with C++

As the demand for web applications grows, so does the demand for tools that support them. As a general rule, such tools extend general purpose programming languages, like Servlets/Jsp [2] does for Java [4], or define their own programming language, like PHP [3]. But there is no established engine for web applications written with C++. This work presents technical challenges that were faced when developing T++, an engine that supports web application development with C++.