SwiftLint/Source/swiftlint/Commands/Rules.swift

import ArgumentParser
#if canImport(Darwin)
import Darwin
#elseif canImport(Glibc)
import Glibc
#else
#error("Unsupported platform")
#endif
import Foundation
import SwiftLintFramework
import SwiftyTextTable

enum RuleEnablementOptions: String, EnumerableFlag {
    case enabled, disabled

    static func name(for value: RuleEnablementOptions) -> NameSpecification {
        return .shortAndLong
    }

    static func help(for value: RuleEnablementOptions) -> ArgumentHelp? {
        return "Only show \(value.rawValue) rules"
    }
}

extension SwiftLint {
    struct Rules: ParsableCommand {
        static let configuration = CommandConfiguration(abstract: "Display the list of rules and their identifiers")

        @Option(help: "The path to a SwiftLint configuration file")
        var config: String?
        @Flag(exclusivity: .exclusive)
        var ruleEnablement: RuleEnablementOptions?
        @Flag(name: .shortAndLong, help: "Only display correctable rules")
        var correctable = false
        @Flag(name: .shortAndLong, help: "Display full configuration details")
        var verbose = false
        @Argument(help: "The rule identifier to display description for")
        var ruleID: String?

        mutating func run() throws {
            if let ruleID = ruleID {
                guard let rule = primaryRuleList.list[ruleID] else {
                    throw SwiftLintError.usageError(description: "No rule with identifier: \(ruleID)")
                }

                rule.description.printDescription()
                return
            }

            let configuration = Configuration(configurationFiles: [config].compactMap({ $0 }))
            let rules = ruleList(configuration: configuration)
            let table = TextTable(ruleList: rules, configuration: configuration, verbose: verbose)
            print(table.render())
        }

        private func ruleList(configuration: Configuration) -> RuleList {
            guard ruleEnablement != nil || correctable else {
                return primaryRuleList
            }

            let filtered: [Rule.Type] = primaryRuleList.list.compactMap { ruleID, ruleType in
                let configuredRule = configuration.rules.first { rule in
                    return type(of: rule).description.identifier == ruleID
                }

                if ruleEnablement == .enabled && configuredRule == nil {
                    return nil
                } else if ruleEnablement == .disabled && configuredRule != nil {
                    return nil
                } else if correctable && !(configuredRule is CorrectableRule) {
                    return nil
                }

                return ruleType
            }

            return RuleList(rules: filtered)
        }
    }
}

private extension RuleDescription {
    func printDescription() {
        print("\(consoleDescription)")

        guard !triggeringExamples.isEmpty else { return }

        func indent(_ string: String) -> String {
            return string.components(separatedBy: "\n")
                .map { "    \($0)" }
                .joined(separator: "\n")
        }
        print("\nTriggering Examples (violation is marked with '↓'):")
        for (index, example) in triggeringExamples.enumerated() {
            print("\nExample #\(index + 1)\n\n\(indent(example.code))")
        }
    }
}

// MARK: - SwiftyTextTable

private extension TextTable {
    init(ruleList: RuleList, configuration: Configuration, verbose: Bool) {
        let columns = [
            TextTableColumn(header: "identifier"),
            TextTableColumn(header: "opt-in"),
            TextTableColumn(header: "correctable"),
            TextTableColumn(header: "enabled in your config"),
            TextTableColumn(header: "kind"),
            TextTableColumn(header: "analyzer"),
            TextTableColumn(header: "configuration")
        ]
        self.init(columns: columns)
        let sortedRules = ruleList.list.sorted { $0.0 < $1.0 }
        func truncate(_ string: String) -> String {
            let stringWithNoNewlines = string.replacingOccurrences(of: "\n", with: "\\n")
            let minWidth = "configuration".count - "...".count
            let configurationStartColumn = 124
            let maxWidth = verbose ? Int.max : Terminal.currentWidth()
            let truncatedEndIndex = stringWithNoNewlines.index(
                stringWithNoNewlines.startIndex,
                offsetBy: max(minWidth, maxWidth - configurationStartColumn),
                limitedBy: stringWithNoNewlines.endIndex
            )
            if let truncatedEndIndex = truncatedEndIndex {
                return stringWithNoNewlines[..<truncatedEndIndex] + "..."
            }
            return stringWithNoNewlines
        }
        for (ruleID, ruleType) in sortedRules {
            let rule = ruleType.init()
            let configuredRule = configuration.rules.first { rule in
                guard type(of: rule).description.identifier == ruleID else {
                    return false
                }
                guard let customRules = rule as? CustomRules else {
                    return true
                }
                return !customRules.configuration.customRuleConfigurations.isEmpty
            }
            addRow(values: [
                ruleID,
                (rule is OptInRule) ? "yes" : "no",
                (rule is CorrectableRule) ? "yes" : "no",
                configuredRule != nil ? "yes" : "no",
                ruleType.description.kind.rawValue,
                (rule is AnalyzerRule) ? "yes" : "no",
                truncate((configuredRule ?? rule).configurationDescription)
            ])
        }
    }
}

private struct Terminal {
    static func currentWidth() -> Int {
        var size = winsize()
#if os(Linux)
        _ = ioctl(CInt(STDOUT_FILENO), UInt(TIOCGWINSZ), &size)
#else
        _ = ioctl(STDOUT_FILENO, TIOCGWINSZ, &size)
#endif
        return Int(size.ws_col)
    }
}