Chronos: Visualizing Slices of Source-Code History.

Abstract

In this paper, we present CHRONOS—a tool that enables the querying, exploration, and discovery of historical change events to source code. Unlike traditional Revision Control-System tools, CHRONOS allows queries across any subset of the code, down to the line-level, which can potentially be contiguous or disparate, even among multiple files. In addition, CHRONOS provides change history across all historical versions (i.e., it is not limited to a pairwise “diff”). The tool implements a zoom-able user interface as a visualization of the history of the queried code to provide both a high-level view of the changes, which supports pattern recognition and discovery, and a low level view that supports semantic comprehension for tasks such as reverse engineering and identifying design rationale. In this paper, we describe use cases in which CHRONOS may be helpful, provide a motivating example to demonstrate the benefits brought by CHRONOS, and describe its visualization in detail.