SwiftLint/Source/SwiftLintBuiltInRules/Rules/Idiomatic/FileNameNoSpaceRule.swift

import Foundation
import SourceKittenFramework

struct FileNameNoSpaceRule: OptInRule, SourceKitFreeRule {
    var configuration = FileNameNoSpaceConfiguration()

    static let description = RuleDescription(
        identifier: "file_name_no_space",
        name: "File Name no Space",
        description: "File name should not contain any whitespace",
        kind: .idiomatic
    )

    func validate(file: SwiftLintFile) -> [StyleViolation] {
        guard let filePath = file.path,
              case let fileName = filePath.bridge().lastPathComponent,
              !configuration.excluded.contains(fileName),
              fileName.rangeOfCharacter(from: .whitespaces) != nil else {
            return []
        }

        return [
            StyleViolation(
                ruleDescription: Self.description,
                severity: configuration.severity,
                location: Location(file: filePath, line: 1)
            ),
        ]
    }
}