swift-code-metrics 1.0.1

Code metrics analyzer for Swift projects.

swift-code-metrics

Code metrics analyzer for Swift projects.

Introduction

The goal of this software is to provide an insight of the architectural state of a software written in Swift that consists in several modules. Inspired by the book of Robert C. Martin, Clean Architecture, the software will scan the project to identify the different components in order to assess:

• the overall number of concrete classes and interfaces
• the instability and abstractness of the framework
• the distance from the main sequence In addition, several common code metrics in the software industries are provided as part of the analysis, such as:
• LOC (Lines Of Code)
• NOC (Numbers Of Comments)
• POC (Percentage Of Comments)
• NBM (Number of Methods)
• Number of concretes (Number of classes and structs)

Requirements

This is a Python 3 script that depends on matplotlib.

Usage

The package is available on pip with pip3 install swift-code-metrics.

The syntax is:

swift-code-metrics --source <path-to-swift-project> --artifacts <output-directory> --exclude <excluded-folders> --generate-graphs

• --source is the path to the folder that contains the main Xcode project or Workspace
• --artifacts path to the folder that will contain the generated output.json report
• --excluded (optional) space separated list of path substrings to exclude from analysis (e.g. Tests will ignore all files/folders that contain Tests)
• --generate-graphs (optional) if passed, it will generate the graphs related to the analysis and save them in the artifacts folder

A sample project is provided in the resources folder; example:

python3 swift-code-metrics-runner.py --source tests/test_resources/ExampleProject/SwiftCodeMetricsExample --artifacts report --exclude Tests xcodeproj --generate-graphs

Output format

The output.json file will contain the metrics related to all frameworks and an aggregate result for the project in the global section.

The example below is available here.

{
    "frameworks": [
        {
            "FoundationFramework": {
                "loc": 26,
                "noc": 14,
                "poc": 35.0,
                "fan_in": 1,
                "fan_out": 2,
                "i": 0.6666666666666666,
                "n_a": 1,
                "n_c": 2,
                "a": 0.5,
                "d_3": 0.16666666666666652,
                "nbm": 3,
                "analysis": "\n(Zone of Uselessness). Maximally abstract with few or no dependents - potentially useless.\nThis component is high likely a leftover that should be removed."
            }
        },
        { ... }
    ],
    "global": {
        "loc": 97,
        "noc": 35,
        "n_a": 1,
        "n_c": 7,
        "nbm": 10,
        "poc": 26.515151515151516
    }
 }

Legend:

Key	Metric	Description
loc	Lines Of Code	Number of lines of code (empty lines excluded)
noc	Number of Comments	Number of comments
poc	Percentage of Comments	100 * noc / ( noc + loc)
fan_in	Fan-In	Incoming dependencies: number of classes outside the framework that depend on classes inside it.
fan_out	Fan-Out	Outgoing dependencies: number of classes inside this component that depend on classes outside it.
i	Instability	I = fan_out / (fan_in + fan_out)
n_a	Number of abstracts	Number of protocols in the framework
n_c	Number of concretes	Number of struct and classes in the framework
a	Abstractness	A = n_a / n_c
d_3	Distance from the main sequence	D³ = abs( A + I - 1 )
nbm	Number of methods	Number of func (computed var excluded)

Current limitations

• This tool is designed for medium/large codebases composed by different frameworks. The script will scan the directory and it will identify the frameworks by the name of the 'root' folder, so it's strictly dependent on the file hierarchy.

• Libraries built with spm are not supported.

• The framework name is inferred using the directory structure. If the file is in the root dir, the default_framework_name will be used. No inspection of the xcodeproj will be made.

• The list of methods currently doesn't support computed vars

• Inline comments in code (such as struct Data: {} //dummy data) are currently not supported

TODOs

• Code improvements
• Setting up CI
• Other (open to suggestions)

Contact

Mattia Campolese