add ability to cancel runtime downloads

Author: MattKiazyk

Xcodes/Backend/AppState+Runtimes.swift

@@ -46,16 +46,33 @@ extension AppState {
     }
 
     func downloadRuntime(runtime: DownloadableRuntime) {
-        Task {
+        runtimePublishers[runtime.identifier] = Task {
             do {
-                try await downloadRunTimeFull(runtime: runtime)
+                let downloadedURL = try await downloadRunTimeFull(runtime: runtime)
+                if !Task.isCancelled {
+                    Logger.appState.debug("Installing rungtime: \(runtime.name)")
+                    DispatchQueue.main.async {
+                        self.setInstallationStep(of: runtime, to: .installing)
+                    }
+                    switch runtime.contentType {
+                    case .package:
+                        // not supported yet (do we need to for old packages?)
+                        throw "Installing via package not support - please install manually from \(downloadedURL.description)"
+                    case .diskImage:
+                        try await self.installFromImage(dmgURL: downloadedURL)
+                        DispatchQueue.main.async {
+                            self.setInstallationStep(of: runtime, to: .trashingArchive)
+                        }
+                        try Current.files.removeItem(at: downloadedURL)
+                    }
 
-                DispatchQueue.main.async {
-                    guard let index = self.downloadableRuntimes.firstIndex(where: { $0.identifier == runtime.identifier }) else { return }
-                    self.downloadableRuntimes[index].installState = .installed
+                    DispatchQueue.main.async {
+                        guard let index = self.downloadableRuntimes.firstIndex(where: { $0.identifier == runtime.identifier }) else { return }
+                        self.downloadableRuntimes[index].installState = .installed
+                    }
+                    updateInstalledRuntimes()
                 }
-                
-                updateInstalledRuntimes()
+              
             }
             catch {
                 Logger.appState.error("Error downloading runtime: \(error.localizedDescription)")
@@ -67,38 +84,44 @@ extension AppState {
         }
     }
 
-    func downloadRunTimeFull(runtime: DownloadableRuntime) async throws {
+    func downloadRunTimeFull(runtime: DownloadableRuntime) async throws -> URL {
         // sets a proper cookie for runtimes
         try await validateADCSession(path: runtime.downloadPath)
 
         let downloader = Downloader(rawValue: UserDefaults.standard.string(forKey: "downloader") ?? "aria2") ?? .aria2
-        Logger.appState.info("Downloading \(runtime.visibleIdentifier) with \(downloader)")
 
-        
-        let url = try await self.downloadRuntime(for: runtime, downloader: downloader, progressChanged: { [unowned self] progress in
-            DispatchQueue.main.async {
-                self.setInstallationStep(of: runtime, to: .downloading(progress: progress))
-            }
-        }).async()
-        
-        Logger.appState.debug("Done downloading: \(url)")
-        DispatchQueue.main.async {
-            self.setInstallationStep(of: runtime, to: .installing)
+        let url = URL(string: runtime.source)!
+        let expectedRuntimePath = Path.xcodesApplicationSupport/"\(url.lastPathComponent)"
+        // aria2 downloads directly to the destination (instead of into /tmp first) so we need to make sure that the download isn't incomplete
+        let aria2DownloadMetadataPath = expectedRuntimePath.parent/(expectedRuntimePath.basename() + ".aria2")
+        var aria2DownloadIsIncomplete = false
+        if case .aria2 = downloader, aria2DownloadMetadataPath.exists {
+            aria2DownloadIsIncomplete = true
         }
-        switch runtime.contentType {
-        case .package:
-            // not supported yet (do we need to for old packages?)
-            throw "Installing via package not support - please install manually from \(url.description)"
-        case .diskImage:
-            try await self.installFromImage(dmgURL: url)
-            DispatchQueue.main.async {
-                self.setInstallationStep(of: runtime, to: .trashingArchive)
-            }
-            try Current.files.removeItem(at: url)
+        if Current.files.fileExistsAtPath(expectedRuntimePath.string), aria2DownloadIsIncomplete == false {
+            Logger.appState.info("Found existing runtime that will be used for installation at \(expectedRuntimePath).")
+            return expectedRuntimePath.url
+        }
+        
+        Logger.appState.info("Downloading \(runtime.visibleIdentifier) with \(downloader)")
+        switch downloader {
+        case .aria2:
+            let aria2Path = Path(url: Bundle.main.url(forAuxiliaryExecutable: "aria2c")!)!
+                for try await progress in downloadRuntimeWithAria2(runtime, to: expectedRuntimePath, aria2Path: aria2Path) {
+                    DispatchQueue.main.async {
+                        Logger.appState.debug("Downloading: \(progress.fractionCompleted)")
+                        self.setInstallationStep(of: runtime, to: .downloading(progress: progress))
+                    }
+                }
+                Logger.appState.debug("Done downloading")
+
+        case .urlSession:
+            throw "Downloading runtimes with URLSession is not supported. Please use aria2"
         }
+        return expectedRuntimePath.url
     }
+
 
-    @MainActor
     func downloadRuntime(for runtime: DownloadableRuntime, downloader: Downloader, progressChanged: @escaping (Progress) -> Void) -> AnyPublisher<URL, Error> {
         // Check to see if the dmg is in the expected path in case it was downloaded but failed to install
 
@@ -156,9 +179,36 @@ extension AppState {
             .eraseToAnyPublisher()
     }
 
+    public func downloadRuntimeWithAria2(_ runtime: DownloadableRuntime, to destination: Path, aria2Path: Path) -> AsyncThrowingStream<Progress, Error> {
+        let cookies = AppleAPI.Current.network.session.configuration.httpCookieStorage?.cookies(for: runtime.url) ?? []
+    
+        return Current.shell.downloadWithAria2Async(aria2Path, runtime.url, destination, cookies)
+    }
+    
+    
     public func installFromImage(dmgURL: URL) async throws {
         try await self.runtimeService.installRuntimeImage(dmgURL: dmgURL)
     }
+    
+    func cancelRuntimeInstall(runtime: DownloadableRuntime) {
+        // Cancel the publisher
+        
+        runtimePublishers[runtime.identifier]?.cancel()
+        runtimePublishers[runtime.identifier] = nil
+        
+        // If the download is cancelled by the user, clean up the download files that aria2 creates.
+        let url = URL(string: runtime.source)!
+        let expectedRuntimePath = Path.xcodesApplicationSupport/"\(url.lastPathComponent)"
+        let aria2DownloadMetadataPath = expectedRuntimePath.parent/(expectedRuntimePath.basename() + ".aria2")
+   
+        try? Current.files.removeItem(at: expectedRuntimePath.url)
+        try? Current.files.removeItem(at: aria2DownloadMetadataPath.url)
+        
+        guard let index = self.downloadableRuntimes.firstIndex(where: { $0.identifier == runtime.identifier }) else { return }
+        self.downloadableRuntimes[index].installState = .notInstalled
+        
+        updateInstalledRuntimes()
+    }
 }
 
 extension AnyPublisher {
@@ -181,3 +231,42 @@ extension AnyPublisher {
         }
     }
 }
+extension AnyPublisher where Failure: Error {
+    struct Subscriber {
+        fileprivate let send: (Output) -> Void
+        fileprivate let complete: (Subscribers.Completion<Failure>) -> Void
+
+        func send(_ value: Output) { self.send(value) }
+        func send(completion: Subscribers.Completion<Failure>) { self.complete(completion) }
+    }
+
+    init(_ closure: (Subscriber) -> AnyCancellable) {
+        let subject = PassthroughSubject<Output, Failure>()
+
+        let subscriber = Subscriber(
+            send: subject.send,
+            complete: subject.send(completion:)
+        )
+        let cancel = closure(subscriber)
+
+        self = subject
+            .handleEvents(receiveCancel: cancel.cancel)
+            .eraseToAnyPublisher()
+    }
+}
+
+extension AnyPublisher where Failure == Error {
+    init(taskPriority: TaskPriority? = nil, asyncFunc: @escaping () async throws -> Output) {
+        self.init { subscriber in
+            let task = Task(priority: taskPriority) {
+                do {
+                    subscriber.send(try await asyncFunc())
+                    subscriber.send(completion: .finished)
+                } catch {
+                    subscriber.send(completion: .failure(error))
+                }
+            }
+            return AnyCancellable { task.cancel() }
+        }
+    }
+}

Xcodes/Backend/AppState.swift

@@ -112,7 +112,7 @@ class AppState: ObservableObject {
 
     var cancellables = Set<AnyCancellable>()
     private var installationPublishers: [Version: AnyCancellable] = [:]
-    internal var runtimePublishers: [String: AnyCancellable] = [:]
+    internal var runtimePublishers: [String: Task<(), any Error>] = [:]
     private var selectPublisher: AnyCancellable?
     private var uninstallPublisher: AnyCancellable?
     private var autoInstallTimer: Timer?

Xcodes/Backend/Environment.swift

@@ -111,9 +111,84 @@ public struct Shell {
 
         return (progress, publisher)
     }
-    // TODO: Support using aria2 using AysncStream/AsyncSequence
-//    public var downloadWithAria2Async: (Path, URL, Path, [HTTPCookie]) async throws -> Progress = { aria2Path, url, destination, cookies in
-
+    
+    public var downloadWithAria2Async: (Path, URL, Path, [HTTPCookie]) -> AsyncThrowingStream<Progress, Error> = { aria2Path, url, destination, cookies in
+        return AsyncThrowingStream<Progress, Error> { continuation in
+ 
+            Task {
+                var progress = Progress()
+                progress.kind = .file
+                progress.fileOperationKind = .downloading
+                
+                let process = Process()
+                process.executableURL = aria2Path.url
+                process.arguments = [
+                    "--header=Cookie: \(cookies.map { "\($0.name)=\($0.value)" }.joined(separator: "; "))",
+                    "--max-connection-per-server=16",
+                    "--split=16",
+                    "--summary-interval=1",
+                    "--stop-with-process=\(ProcessInfo.processInfo.processIdentifier)", // if xcodes quits, stop aria2 process
+                    "--dir=\(destination.parent.string)",
+                    "--out=\(destination.basename())",
+                    "--human-readable=false", // sets the output to use bytes instead of formatting
+                    url.absoluteString,
+                ]
+                let stdOutPipe = Pipe()
+                process.standardOutput = stdOutPipe
+                let stdErrPipe = Pipe()
+                process.standardError = stdErrPipe
+                
+                let observer = NotificationCenter.default.addObserver(
+                    forName: .NSFileHandleDataAvailable,
+                    object: nil,
+                    queue: OperationQueue.main
+                ) { note in
+                    guard
+                        // This should always be the case for Notification.Name.NSFileHandleDataAvailable
+                        let handle = note.object as? FileHandle,
+                        handle === stdOutPipe.fileHandleForReading || handle === stdErrPipe.fileHandleForReading
+                    else { return }
+                    
+                    defer { handle.waitForDataInBackgroundAndNotify() }
+                    
+                    let string = String(decoding: handle.availableData, as: UTF8.self)
+                    // TODO: fix warning. ObservingProgressView is currently tied to an updating progress
+                    progress.updateFromAria2(string: string)
+                    
+                    continuation.yield(progress)
+                }
+                
+                stdOutPipe.fileHandleForReading.waitForDataInBackgroundAndNotify()
+                stdErrPipe.fileHandleForReading.waitForDataInBackgroundAndNotify()
+                
+                continuation.onTermination = { @Sendable _ in
+                    process.terminate()
+                    NotificationCenter.default.removeObserver(observer, name: .NSFileHandleDataAvailable, object: nil)
+                }
+                
+                do {
+                    try process.run()
+                } catch {
+                    continuation.finish(throwing: error)
+                }
+                
+                process.waitUntilExit()
+                
+                NotificationCenter.default.removeObserver(observer, name: .NSFileHandleDataAvailable, object: nil)
+                
+                guard process.terminationReason == .exit, process.terminationStatus == 0 else {
+                    if let aria2cError = Aria2CError(exitStatus: process.terminationStatus) {
+                        continuation.finish(throwing: aria2cError)
+                    } else {
+                        continuation.finish(throwing: ProcessExecutionError(process: process, standardOutput: "", standardError: ""))
+                    }
+                    return
+                }
+                continuation.finish()
+            }
+        }
+    }
+    
 
     public var unxipExperiment: (URL) -> AnyPublisher<ProcessOutput, Error> = { url in
         let unxipPath = Path(url: Bundle.main.url(forAuxiliaryExecutable: "unxip")!)!

Xcodes/Backend/XcodeCommands.swift

@@ -67,6 +67,23 @@ struct CancelInstallButton: View {
     }
 }
 
+struct CancelRuntimeInstallButton: View {
+    @EnvironmentObject var appState: AppState
+    let runtime: DownloadableRuntime?
+    
+    var body: some View {
+        Button(action: cancelInstall) {
+            Text("Cancel")
+                .help(localizeString("StopInstallation"))
+        }
+    }
+    
+    private func cancelInstall() {
+        guard let runtime = runtime else { return }
+        appState.presentedAlert = .cancelRuntimeInstall(runtime: runtime)
+    }
+}
+
 struct SelectButton: View {
     @EnvironmentObject var appState: AppState
     let xcode: Xcode?

Xcodes/Frontend/Common/XcodesAlert.swift

@@ -1,7 +1,9 @@
 import Foundation
+import XcodesKit
 
 enum XcodesAlert: Identifiable {
     case cancelInstall(xcode: Xcode)
+    case cancelRuntimeInstall(runtime: DownloadableRuntime)
     case privilegedHelper
     case generic(title: String, message: String)
     case checkMinSupportedVersion(xcode: AvailableXcode, macOS: String)
@@ -12,6 +14,7 @@ enum XcodesAlert: Identifiable {
         case .privilegedHelper: return 2
         case .generic: return 3
         case .checkMinSupportedVersion: return 4
+        case .cancelRuntimeInstall: return 5
         }
     }
 }