Swift Argument Parser for the CLI

Allows for a simpler, more maintainable CLI.

Author: liamrosenfeld

.travis.yml

@@ -1,5 +1,5 @@
 language: rust
-osx_image: xcode10.2
+osx_image: xcode11.3
 
 git:
   submodules: true

README.md

@@ -120,23 +120,14 @@ XiEditor includes a CLI for opening files directly from the command line.
 ### Usage
 
 ```text
-xi <file> [--wait | -w] [--help | -h]
-  open XiEditor at specified file path
+USAGE: xi [<files> ...] [--wait]
 
-  file
-    the path to the file (relative or absolute)
+ARGUMENTS:
+  <files>                 Relative or absolute path to the file(s) to open. If none, opens empty editor.
 
-  --wait, -w
-    wait for the editor to close
-
-  --help, -h
-    prints this
-
-xi [--help | -h]
-  open XiEditor
-
-  --help, -h
-    prints this
+OPTIONS:
+  --wait                  Wait for the editor to close before finishing process.
+  -h, --help              Show help information.
 ```
 
 ### Git Editor

Sources/XiCli/main.swift

@@ -12,15 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import Foundation
 import XiCliCore
 
-let args = Arguments()
-let tool = CommandLineTool(args: args)
-
-do {
-    try tool.run()
-} catch {
-    print("Whoops! An error occurred: \(error)")
-    exit(1)
-}
+Xi.main()

Sources/XiCliCore/CommandLineTool.swift renamed to Sources/XiCliCore/CliHelper.swift

@@ -1,4 +1,4 @@
-// Copyright 2018 The xi-editor Authors.
+// Copyright 2020 The xi-editor Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -12,44 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import Cocoa
+import AppKit
+import ArgumentParser
 
-public final class CommandLineTool {
-    private let args: Arguments
-    
-    public init(args: Arguments) {
-        self.args = args
-    }
-    
-    public func run() throws {
-        if args.help == true {
-            help()
-            return
-        }
-        
-        guard !args.fileInputs.isEmpty else {
-            NSWorkspace.shared.launchApplication("XiEditor")
-            return
-        }
-
-        let filePaths = try args.fileInputs.map {
-            try resolvePath(from: $0)
-        }
-
-        for filePath in filePaths {
-            try openFile(at: filePath)
-        }
-
-        if args.wait, !filePaths.isEmpty {
-            print("waiting for editor to close...")
-            let group = DispatchGroup()
-            group.enter()
-            setObserver(group: group, filePaths: filePaths)
-            group.wait()
-        }
-    }
-    
-    func resolvePath(from input: String) throws -> String {
+struct CliHelper {
+    static func resolvePath(from input: String) throws -> String {
         let fileManager = FileManager.default
         var filePath: URL!
 
@@ -66,28 +33,28 @@ public final class CommandLineTool {
         let pathString = canonicalPath(input)
 
         guard pathIsNotDirectory(pathString) else {
-            throw CliError.pathIsDirectory
+            throw ValidationError("The path entered is to a directory")
         }
 
         if !fileManager.fileExists(atPath: pathString) {
             let createSuccess = fileManager.createFile(atPath: pathString, contents: nil, attributes: nil)
 
             guard createSuccess else {
-                throw CliError.couldNotCreateFile
+                throw RuntimeError("Could not create a file")
             }
         }
 
         return pathString
     }
 
-    func openFile(at path: String) throws {
+    static func openFile(at path: String) throws {
         let openSuccess = NSWorkspace.shared.openFile(path, withApplication: "XiEditor")
         guard openSuccess else {
-            throw CliError.failedToOpenEditor
+            throw RuntimeError("Xi editor could not be opened")
         }
     }
 
-    func setObserver(group: DispatchGroup, filePaths: [String]) {
+    static func setObserver(group: DispatchGroup, filePaths: [String]) {
         let notificationQueue: OperationQueue = {
             let queue = OperationQueue()
             queue.name = "Notification queue"
@@ -110,33 +77,9 @@ public final class CommandLineTool {
             }
         }
     }
-    
-    func help() {
-        let message = """
-                The Xi CLI Help:
-                xi <file>... [--wait | -w] [--help | -h]
-
-                file
-                    the path to the file (relative or absolute)
-
-                --wait, -w
-                    wait for the editor to close
-
-                --help, -h
-                    prints this
-                """
-        print(message)
-    }
 
-    func canonicalPath(_ path: String) -> String {
+    static func canonicalPath(_ path: String) -> String {
         return URL(fileURLWithPath: path).standardizedFileURL.resolvingSymlinksInPath().path
     }
 }
 
-public extension CommandLineTool {
-    enum CliError: Swift.Error {
-        case couldNotCreateFile
-        case failedToOpenEditor
-        case pathIsDirectory
-    }
-}

Sources/XiCliCore/Arguments.swift renamed to Sources/XiCliCore/RuntimeError.swift

@@ -1,4 +1,4 @@
-// Copyright 2018 The xi-editor Authors.
+// Copyright 2020 The xi-editor Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -12,22 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-public struct Arguments {
-    var fileInputs: [String] = []
-    var wait: Bool = false
-    var help: Bool = false
+import Foundation
+
+struct RuntimeError: Error, CustomStringConvertible {
+    var description: String
 
-    public init(arguments: [String] = CommandLine.arguments) {
-        let actualArgs = Array(arguments.dropFirst())
-        for arg in actualArgs {
-            if arg == "--wait" || arg == "-w" {
-                self.wait = true
-            } else if arg == "--help" || arg == "-h" {
-                self.help = true
-            } else {
-                self.fileInputs.append(arg)
-            }
-        }
+    init(_ description: String) {
+        self.description = description
     }
 }
-

Sources/XiCliCore/Xi.swift

@@ -0,0 +1,52 @@
+// Copyright 2020 The xi-editor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import ArgumentParser
+import AppKit
+
+public struct Xi: ParsableCommand {
+    @Argument(help: "Relative or absolute path to the file(s) to open. If none, opens empty editor.")
+    var files: [String]
+    
+    @Flag(help: "Wait for the editor to close before finishing process.")
+    var wait: Bool
+    
+    public init() {}
+    
+    public func run() throws {
+
+        guard !files.isEmpty else {
+            NSWorkspace.shared.launchApplication("XiEditor")
+            return
+        }
+
+        let filePaths = try files.map {
+            try CliHelper.resolvePath(from: $0)
+        }
+
+        for filePath in filePaths {
+            try CliHelper.openFile(at: filePath)
+        }
+
+        if wait, !filePaths.isEmpty {
+            print("waiting for editor to close...")
+            let group = DispatchGroup()
+            group.enter()
+            CliHelper.setObserver(group: group, filePaths: filePaths)
+            group.wait()
+        }
+    }
+}
+
+

Tests/XiCliCoreTests/XiCliCoreTests.swift renamed to Tests/XiCliCoreTests/CliHelperTests.swift

@@ -1,4 +1,4 @@
-// Copyright 2018 The xi-editor Authors.
+// Copyright 2020 The xi-editor Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -15,14 +15,9 @@
 import XCTest
 @testable import XiCliCore
 
-class XiCliCoreTests: XCTestCase {
-
-    var commandLineTool: CommandLineTool!
-    
+class CliHelperTests: XCTestCase {
     override func setUp() {
         super.setUp()
-        let testArguments = Arguments(arguments: ["test.txt", "--wait"])
-        commandLineTool = CommandLineTool(args: testArguments)
         let fileManager = FileManager.default
         fileManager.createFile(atPath: "test.txt", contents: "This is a tester file".data(using: .utf8), attributes: nil)
         try? fileManager.createSymbolicLink(atPath: "test_link.txt", withDestinationPath: "test.txt")
@@ -33,23 +28,14 @@ class XiCliCoreTests: XCTestCase {
         try? FileManager.default.removeItem(atPath: "test_link.txt")
         try? FileManager.default.removeItem(atPath: "test.txt")
     }
-
-    func testArgParse() {
-        let arguments = ["xi", "--wait", "test1.txt", "test2.txt"]
-        let retrievedArgs = Arguments(arguments: arguments)
-        XCTAssertNotNil(retrievedArgs)
-        XCTAssert(retrievedArgs.fileInputs == ["test1.txt", "test2.txt"])
-        XCTAssert(retrievedArgs.wait == true)
-        XCTAssert(retrievedArgs.help == false)
-    }
-
+    
     func testResolveAbsolutePath() {
         let fromPath = fileInTempDir("testResolvePath")
         FileManager
             .default
             .createFile(atPath: fromPath, contents: "This is a tester file".data(using: .utf8), attributes: nil)
         do {
-            let path = try commandLineTool.resolvePath(from: fromPath)
+            let path = try CliHelper.resolvePath(from: fromPath)
             XCTAssert(path == fromPath)
         } catch {
             XCTFail("temp file in temp dir not found")
@@ -58,7 +44,7 @@ class XiCliCoreTests: XCTestCase {
 
     func testResolveRelativePath() {
         do {
-            let path = try commandLineTool.resolvePath(from: "test.txt")
+            let path = try CliHelper.resolvePath(from: "test.txt")
             let expectedPath = fileInCurrentDir("test.txt")
             XCTAssert(path == expectedPath, "path does not match expected")
         } catch {
@@ -68,7 +54,7 @@ class XiCliCoreTests: XCTestCase {
 
     func testResolveSymlink() {
         do {
-            let path = try commandLineTool.resolvePath(from: "test_link.txt")
+            let path = try CliHelper.resolvePath(from: "test_link.txt")
             let expectedPath = fileInCurrentDir("test.txt")
             XCTAssert(path == expectedPath, "path does not match expected")
         } catch {
@@ -77,15 +63,15 @@ class XiCliCoreTests: XCTestCase {
     }
 
     func testFileOpen() {
-        XCTAssertNoThrow(try commandLineTool.openFile(at: "test.txt"))
+        XCTAssertNoThrow(try CliHelper.openFile(at: "test.txt"))
     }
 
     func testObserver() {
         let group = DispatchGroup()
         group.enter()
         let observedPaths = ["filePath1", "test_link.txt"]
         let expectedPaths = [fileInCurrentDir("filePath1"), fileInCurrentDir("test.txt")]
-        commandLineTool.setObserver(group: group, filePaths: expectedPaths)
+        CliHelper.setObserver(group: group, filePaths: expectedPaths)
         DistributedNotificationCenter.default().post(name: Notification.Name("io.xi-editor.XiEditor.FileClosed"), object: nil, userInfo: ["path": observedPaths.first!])
         DistributedNotificationCenter.default().post(name: Notification.Name("io.xi-editor.XiEditor.FileClosed"), object: nil, userInfo: ["path": observedPaths.last!])
         let expectation = XCTestExpectation(description: "Notification Recieved")