Reactive methodologies to infinite text processing

• Autor(a) principal: João Saffran de Rezende
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/58695
• topic: Computação; Linguagem de programação (Computadores); Programação reativa; Análise (Gramática de computador); Computação – Teses; Linguagem de programação (Computadores) – Teses; Programação reativa – Teses; Análise (Gramática de computador) – Teses

A string event is the occurrence of a specific pattern in the textual output of a program. The capture and treatment of string events has several applications, such as log anonymization, error handling and user notification, implementing web crawler and performing code refactoring. However, there is no systematic approach to identify and treat string events today. This work formally defines string events and brings forward the theory and practice of a general framework to handle them. We demonstrate the effectiveness of this framework by presenting two implementations that use it. First we introduce ZheFuscator, a system that redacts occurrences of sensitive information in database logs. ZheFuscator is implemented as an extension to the Java Virtual Machine (JVM). It intercepts patterns of interest on-the-fly and does not require interventions in the source code of the protected program. It can infer log formats and capture string events with minimal performance overhead. As an illustration, it is up to 14x faster than an equivalent brute-force approach, converging to a definitive grammar after observing less than 10 examples from typical logs. Second we introduce a general notation to the handling of infinite text processing. This notation highlights commonalities in tasks that, although in principle different, encode the same essential challenges. We have concretized this notation into ZheLang, a reactive language that lets users combine basic operations to identify and treat string events. As a proof of concept, we demonstrate how ZheLang operators can be combined to implement applications as disparate as log obfuscators and search engines.