Make the disk size configurable upon creation (#26)

* Make the disk size configurable upon creation

I haven't found a way to make a VM aware of a larger disk size. So I didn't add `--disk-size` option to `set` command.

* Fixed size so it's pretty in the UI

* Hidden option to resize disk for testing

Sources/tart/Commands/Create.swift

@@ -9,7 +9,11 @@ struct Create: AsyncParsableCommand {
   @Argument(help: "VM name")
   var name: String
 
-  @Option(help: ArgumentHelp("Path to the IPSW file (or \"latest\") to fetch the latest appropriate IPSW", valueName: "path")) var fromIPSW: String?
+  @Option(help: ArgumentHelp("Path to the IPSW file (or \"latest\") to fetch the latest appropriate IPSW", valueName: "path")) 
+  var fromIPSW: String?
+
+  @Option(help: ArgumentHelp("Disk size in Gb")) 
+  var diskSize: UInt8 = 32
 
   func validate() throws {
     if fromIPSW == nil {
@@ -22,9 +26,9 @@ struct Create: AsyncParsableCommand {
       let vmDir = try VMStorage().create(name)
 
       if fromIPSW! == "latest" {
-        _ = try await VM(vmDir: vmDir, ipswURL: nil)
+        _ = try await VM(vmDir: vmDir, ipswURL: nil, diskSizeGB: diskSize)
       } else {
-        _ = try await VM(vmDir: vmDir, ipswURL: URL(fileURLWithPath: fromIPSW!))
+        _ = try await VM(vmDir: vmDir, ipswURL: URL(fileURLWithPath: fromIPSW!), diskSizeGB: diskSize)
       }
 
       Foundation.exit(0)

Sources/tart/Commands/Set.swift

@@ -16,6 +16,9 @@ struct Set: AsyncParsableCommand {
   @Option(help: "VM display settings in a format of <width>x<height>(x<dpi>)?. For example, 1200x800 or 1200x800x72")
   var display: VMDisplayConfig?
 
+  @Option(help: .hidden)
+  var diskSize: UInt8?
+
   func run() async throws {
     do {
       let vmStorage = VMStorage()
@@ -43,6 +46,10 @@ struct Set: AsyncParsableCommand {
       }
 
       try vmConfig.save(toURL: vmDir.configURL)
+      
+      if diskSize != nil {
+        try vmDir.resizeDisk(diskSize!)
+      }
 
       Foundation.exit(0)
     } catch {

Sources/tart/VM.swift

@@ -78,7 +78,7 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
     return expectedIPSWLocation
   }
 
-  init(vmDir: VMDirectory, ipswURL: URL?, diskSize: UInt64 = 32 * 1024 * 1024 * 1024) async throws {
+  init(vmDir: VMDirectory, ipswURL: URL?, diskSizeGB: UInt8) async throws {
     let ipswURL = ipswURL != nil ? ipswURL! : try await VM.retrieveLatestIPSW();
 
     // Load the restore image and try to get the requirements
@@ -97,10 +97,7 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
     let auxStorage = try VZMacAuxiliaryStorage(creatingStorageAt: vmDir.nvramURL, hardwareModel: requirements.hardwareModel)
 
     // Create disk
-    FileManager.default.createFile(atPath: vmDir.diskURL.path, contents: nil, attributes: nil)
-    let diskFileHandle = try FileHandle.init(forWritingTo: vmDir.diskURL)
-    try diskFileHandle.truncate(atOffset: diskSize)
-    try diskFileHandle.close()
+    try vmDir.resizeDisk(diskSizeGB)
 
     name = vmDir.name
     // Create config

Sources/tart/VMDirectory.swift

@@ -39,4 +39,14 @@ struct VMDirectory {
       throw UninitializedVMDirectoryError()
     }
   }
+  
+  func resizeDisk(_ sizeGB: UInt8) throws {
+    if !FileManager.default.fileExists(atPath: diskURL.path) {
+      FileManager.default.createFile(atPath: diskURL.path, contents: nil, attributes: nil)
+    }
+    let diskFileHandle = try FileHandle.init(forWritingTo: diskURL)
+    // macOS considers kilo being 1000 and not 1024
+    try diskFileHandle.truncate(atOffset: UInt64(sizeGB) * 1000 * 1000 * 1000)
+    try diskFileHandle.close()
+  }
 }