SWCompression/Sources/swcomp/Containers/CommonFunctions.swift

// Copyright (c) 2022 Timofey Solomko
// Licensed under MIT License
//
// See LICENSE for license information

import Foundation
import SWCompression

func isValidOutputDirectory(_ outputPath: String, create: Bool) throws -> Bool {
    let fileManager = FileManager.default
    var isDir: ObjCBool = false

    if fileManager.fileExists(atPath: outputPath, isDirectory: &isDir) {
        return isDir.boolValue
    } else if create {
        try fileManager.createDirectory(atPath: outputPath, withIntermediateDirectories: true)
    }
    return true
}

func printInfo(_ entries: [ContainerEntryInfo]) {
    for entry in entries {
        print(entry)
        print("------------------\n")
    }
}

func printList(_ entries: [ContainerEntryInfo]) {
    for entry in entries {
        print(entry.name)
    }
}

func write<T: ContainerEntry>(_ entries: [T], _ outputPath: String, _ verbose: Bool) throws {
    let fileManager = FileManager.default
    let outputURL = URL(fileURLWithPath: outputPath)

    if verbose {
        print("d = directory, f = file, l = symbolic link")
    }

    var directoryAttributes = [(attributes: [FileAttributeKey: Any], path: String)]()

    // First, we create directories.
    for entry in entries where entry.info.type == .directory {
        directoryAttributes.append(try writeDirectory(entry, outputURL, verbose))
    }

    // Now, we create the rest of files.
    for entry in entries where entry.info.type != .directory {
        try writeFile(entry, outputURL, verbose)
    }

    for tuple in directoryAttributes {
        try fileManager.setAttributes(tuple.attributes, ofItemAtPath: tuple.path)
    }
}

func writeDirectory<T: ContainerEntry>(_ entry: T, _ outputURL: URL, _ verbose: Bool) throws -> ([FileAttributeKey: Any], String) {
    let fileManager = FileManager.default
    let entryName = entry.info.name
    let entryFullURL = outputURL.appendingPathComponent(entryName, isDirectory: true)

    if verbose {
        print("d: \(entryName)")
    }
    try fileManager.createDirectory(at: entryFullURL, withIntermediateDirectories: true)

    var attributes = [FileAttributeKey: Any]()

    #if !os(Linux) // On linux only permissions attribute is supported.
        if let mtime = entry.info.modificationTime {
            attributes[FileAttributeKey.modificationDate] = mtime
        }

        if let ctime = entry.info.creationTime {
            attributes[FileAttributeKey.creationDate] = ctime
        }
    #endif

    if let permissions = entry.info.permissions?.rawValue, permissions > 0 {
        attributes[FileAttributeKey.posixPermissions] = NSNumber(value: permissions)
    }

    // We apply attributes to directories later, because extracting files into them changes mtime.
    return (attributes, entryFullURL.path)
}

func writeFile<T: ContainerEntry>(_ entry: T, _ outputURL: URL, _ verbose: Bool) throws {
    let fileManager = FileManager.default
    let entryName = entry.info.name
    let entryFullURL = outputURL.appendingPathComponent(entryName, isDirectory: false)

    if entry.info.type == .symbolicLink {
        let destinationPath: String?
        if let tarEntry = entry as? TarEntry {
            destinationPath = tarEntry.info.linkName
        } else {
            guard let entryData = entry.data
                else { swcompExit(.containerSymLinkDestPath(entryName)) }
            destinationPath = String(data: entryData, encoding: .utf8)
        }
        guard destinationPath != nil
            else { swcompExit(.containerSymLinkDestPath(entryName)) }
        if verbose {
            print("l: \(entryName) -> \(destinationPath!)")
        }
        try fileManager.createSymbolicLink(atPath: entryFullURL.path, withDestinationPath: destinationPath!)
        // We cannot apply attributes to symbolic links.
        return
    } else if entry.info.type == .hardLink {
        guard let destinationPath = (entry as? TarEntry)?.info.linkName
            else { swcompExit(.containerHardLinkDestPath(entryName)) }
        if verbose {
            print("hl: \(entryName) -> \(destinationPath)")
        }
        // Note that the order of parameters is inversed for hard links.
        try fileManager.linkItem(atPath: destinationPath, toPath: entryFullURL.path)
        // We cannot apply attributes to hard links.
        return
    } else if entry.info.type == .regular {
        if verbose {
            print("f: \(entryName)")
        }
        guard let entryData = entry.data
            else { swcompExit(.containerNoEntryData(entryName)) }
        try entryData.write(to: entryFullURL)
    } else {
        print("WARNING: Unknown file type \(entry.info.type) for entry \(entryName). Skipping this entry.")
        return
    }

    var attributes = [FileAttributeKey: Any]()

    #if !os(Linux) // On linux only permissions attribute is supported.
        if let mtime = entry.info.modificationTime {
            attributes[FileAttributeKey.modificationDate] = mtime
        }

        if let ctime = entry.info.creationTime {
            attributes[FileAttributeKey.creationDate] = ctime
        }
    #endif

    if let permissions = entry.info.permissions?.rawValue, permissions > 0 {
        attributes[FileAttributeKey.posixPermissions] = NSNumber(value: permissions)
    }

    try fileManager.setAttributes(attributes, ofItemAtPath: entryFullURL.path)
}