[swcomp] Add ContainerCommand protocol

This protocol represents common functionality for container-related commands (7z and zip). Extension to this protocol implements execute() function which is the same for both 7z and Zip commands.

Sources/swcomp/ContainerCommand.swift

@@ -0,0 +1,51 @@
+// Copyright (c) 2018 Timofey Solomko
+// Licensed under MIT License
+//
+// See LICENSE for license information
+
+import Foundation
+import SWCompression
+import SwiftCLI
+
+protocol ContainerCommand: Command {
+
+    associatedtype Entry: ContainerEntry
+
+    var info: Flag { get }
+    var extract: Key<String> { get}
+    var verbose: Flag { get }
+
+    var archive: Parameter { get }
+
+    var openFunction: (Data) throws -> [Entry] { get }
+    var infoFunction: (Data) throws -> [Entry.Info] { get }
+
+}
+
+extension ContainerCommand {
+
+    var optionGroups: [OptionGroup] {
+        let actions = OptionGroup(options: [info, extract], restriction: .exactlyOne)
+        return [actions]
+    }
+
+    func execute() throws {
+        let fileData = try Data(contentsOf: URL(fileURLWithPath: self.archive.value),
+                                options: .mappedIfSafe)
+        if info.value {
+            let entries = try infoFunction(fileData)
+            swcomp.printInfo(entries)
+        } else {
+            let outputPath = self.extract.value!
+
+            if try !isValidOutputDirectory(outputPath, create: true) {
+                print("ERROR: Specified path already exists and is not a directory.")
+                exit(1)
+            }
+
+            let entries = try openFunction(fileData)
+            try swcomp.write(entries, outputPath, verbose.value)
+        }
+    }
+
+}