[desktop_drop] 0.7.0: macOS: robust multi-source drag & drop (#434)

omar-hanafy · web-flow · commit 4181b95a381d · 2025-09-12T10:34:22.000+08:00
- Prefer public.file-url / NSFilenamesPboardType; fallback to NSFilePromiseReceiver
- Add fromPromise flag; map directories to DropItemDirectory
- Generate security-scoped bookmarks only for paths outside container/tmp
- Per-drop unique destination for promises
- Guards in Dart for empty bookmarks
- Thread-safe collection of drop results
diff --git a/packages/desktop_drop/CHANGELOG.md b/packages/desktop_drop/CHANGELOG.md
@@ -1,5 +1,21 @@
 # Changelog
 
+## 0.7.0
+
+[macOS] Robust multi-source drag & drop.
+
+* Prefer `public.file-url` / legacy filename arrays when present; fall back to
+  `NSFilePromiseReceiver` (file promises) otherwise.
+* Handle directories (`isDirectory`) and surface as `DropItemDirectory`.
+* Add `fromPromise` to `DropItem` so apps can distinguish promise-based drops.
+* Generate security-scoped bookmarks only for paths outside the app container
+  (skip/empty for promise files in `.../tmp/Drops/...`).
+* Per-drop unique destination for promised files to avoid name collisions.
+* Thread-safe collection of drop results when receiving promises.
+* Dart guards: no-op `start/stopAccessingSecurityScopedResource` on empty
+  bookmarks.
+* Bump macOS minimum to 10.13 (SPM/Podspec).
+
 ## 0.6.1
 
 * Fix desktop_drop Linux snap build failure due to missing stdlib.h include (#425)
diff --git a/packages/desktop_drop/lib/src/channel.dart b/packages/desktop_drop/lib/src/channel.dart
@@ -37,8 +37,17 @@ class DesktopDrop {
     });
   }
 
+  /// macOS: Attempt to start security-scoped access for a bookmarked URL.
+  ///
+  /// Pass the [DropItem.extraAppleBookmark] bytes from a dropped file that
+  /// originated outside the app container. Returns `true` if access began.
+  ///
+  /// If [bookmark] is empty, this function returns `false` and does not
+  /// invoke the platform call. Promise files written under your container do
+  /// not require security-scoped access.
   Future<bool> startAccessingSecurityScopedResource(
       {required Uint8List bookmark}) async {
+    if (bookmark.isEmpty) return false;
     Map<String, dynamic> resultMap = {};
     resultMap["apple-bookmark"] = bookmark;
     final bool? result = await _channel.invokeMethod(
@@ -47,8 +56,13 @@ class DesktopDrop {
     return result;
   }
 
+  /// macOS: Stop security-scoped access previously started.
+  ///
+  /// If [bookmark] is empty, this function returns `true` and does not
+  /// invoke the platform call, acting as a no-op.
   Future<bool> stopAccessingSecurityScopedResource(
       {required Uint8List bookmark}) async {
+    if (bookmark.isEmpty) return true;
     Map<String, dynamic> resultMap = {};
     resultMap["apple-bookmark"] = bookmark;
     final bool result = await _channel.invokeMethod(
@@ -89,16 +103,30 @@ class DesktopDrop {
         _offset = null;
         break;
       case "performOperation_macos":
-        // final paths = (call.arguments as List).cast<Map<String?, Object?>>();
-        final paths = call.arguments as List;
+        final items = (call.arguments as List).cast<Map>();
         _notifyEvent(
           DropDoneEvent(
             location: _offset ?? Offset.zero,
-            files: paths
-                .map((e) => DropItemFile(
-                      e["path"] as String,
-                      extraAppleBookmark: e["apple-bookmark"] as Uint8List?,
-                    ))
+            files: items
+                .map((raw) {
+                  final path = raw["path"] as String;
+                  final bookmark = raw["apple-bookmark"] as Uint8List?;
+                  final isDir = (raw["isDirectory"] as bool?) ?? false;
+                  final fromPromise = (raw["fromPromise"] as bool?) ?? false;
+                  if (isDir) {
+                    return DropItemDirectory(
+                      path,
+                      const [],
+                      extraAppleBookmark: bookmark,
+                      fromPromise: fromPromise,
+                    );
+                  }
+                  return DropItemFile(
+                    path,
+                    extraAppleBookmark: bookmark,
+                    fromPromise: fromPromise,
+                  );
+                })
                 .toList(),
           ),
         );
diff --git a/packages/desktop_drop/lib/src/drop_item.dart b/packages/desktop_drop/lib/src/drop_item.dart
@@ -2,8 +2,32 @@ import 'dart:typed_data';
 
 import 'package:cross_file/cross_file.dart';
 
+/// A dropped item.
+///
+/// On desktop, this is usually a filesystem path (file or directory).
+///
+/// macOS specifics:
+/// - If the drag source provided a real file URL (e.g. Finder/JetBrains),
+///   [extraAppleBookmark] will typically be non-null and allow security-scoped
+///   access when running sandboxed.
+/// - If the drag source used a file promise (e.g. VS Code/Electron), the
+///   system delivers bytes into a per-drop temporary folder inside your app's
+///   container. In that case [fromPromise] is true and [extraAppleBookmark]
+///   is usually null/empty. There is no original source path in this flow.
 abstract class DropItem extends XFile {
+  /// Security-scoped bookmark bytes for the dropped item (macOS only).
+  ///
+  /// Use with [DesktopDrop.startAccessingSecurityScopedResource] to gain
+  /// temporary access to files outside your sandbox. When empty or null,
+  /// you typically don't need to call start/stop (e.g. promise files in
+  /// your app's container).
   Uint8List? extraAppleBookmark;
+
+  /// True when this item was delivered via a macOS file promise and was
+  /// written into your app's temporary Drops directory.
+  ///
+  /// In this case, the original source path is not available by design.
+  final bool fromPromise;
   DropItem(
     super.path, {
     super.mimeType,
@@ -12,6 +36,7 @@ abstract class DropItem extends XFile {
     super.bytes,
     super.lastModified,
     this.extraAppleBookmark,
+    this.fromPromise = false,
   });
 
   DropItem.fromData(
@@ -21,6 +46,8 @@ abstract class DropItem extends XFile {
     super.length,
     super.lastModified,
     super.path,
+    this.extraAppleBookmark,
+    this.fromPromise = false,
   }) : super.fromData();
 }
 
@@ -33,6 +60,7 @@ class DropItemFile extends DropItem {
     super.bytes,
     super.lastModified,
     super.extraAppleBookmark,
+    super.fromPromise,
   });
 
   DropItemFile.fromData(
@@ -42,9 +70,11 @@ class DropItemFile extends DropItem {
     super.length,
     super.lastModified,
     super.path,
+    super.fromPromise,
   }) : super.fromData();
 }
 
+/// A dropped directory.
 class DropItemDirectory extends DropItem {
   final List<DropItem> children;
 
@@ -56,6 +86,8 @@ class DropItemDirectory extends DropItem {
     super.length,
     super.bytes,
     super.lastModified,
+    super.extraAppleBookmark,
+    super.fromPromise,
   });
 
   DropItemDirectory.fromData(
@@ -66,5 +98,7 @@ class DropItemDirectory extends DropItem {
     super.length,
     super.lastModified,
     super.path,
+    super.extraAppleBookmark,
+    super.fromPromise,
   }) : super.fromData();
 }
diff --git a/packages/desktop_drop/macos/desktop_drop.podspec b/packages/desktop_drop/macos/desktop_drop.podspec
@@ -16,7 +16,7 @@ A new flutter plugin project.
   s.source_files     = 'desktop_drop/Sources/desktop_drop/**/*.{h,m,swift}'
   s.dependency 'FlutterMacOS'
 
-  s.platform = :osx, '10.11'
+  s.platform = :osx, '10.13'
   s.pod_target_xcconfig = { 'DEFINES_MODULE' => 'YES' }
   s.swift_version = '5.0'
 end
diff --git a/packages/desktop_drop/macos/desktop_drop/Package.swift b/packages/desktop_drop/macos/desktop_drop/Package.swift
@@ -6,7 +6,7 @@ import PackageDescription
 let package = Package(
     name: "desktop_drop",
     platforms: [
-        .macOS("10.11")
+        .macOS("10.13")
     ],
     products: [
         .library(name: "desktop-drop", targets: ["desktop_drop"])
@@ -21,4 +21,4 @@ let package = Package(
             ]
         )
     ]
-)
+)
diff --git a/packages/desktop_drop/macos/desktop_drop/Sources/desktop_drop/DesktopDropPlugin.swift b/packages/desktop_drop/macos/desktop_drop/Sources/desktop_drop/DesktopDropPlugin.swift
@@ -32,8 +32,11 @@ public class DesktopDropPlugin: NSObject, FlutterPlugin {
     let d = DropTarget(frame: vc.view.bounds, channel: channel)
     d.autoresizingMask = [.width, .height]
 
-    d.registerForDraggedTypes(NSFilePromiseReceiver.readableDraggedTypes.map { NSPasteboard.PasteboardType($0) })
-    d.registerForDraggedTypes([NSPasteboard.PasteboardType.fileURL])
+    // Register for all relevant types (promises, URLs, and legacy filename arrays)
+    var types = NSFilePromiseReceiver.readableDraggedTypes.map { NSPasteboard.PasteboardType($0) }
+    types.append(.fileURL) // public.file-url
+    types.append(NSPasteboard.PasteboardType("NSFilenamesPboardType")) // legacy multi-file array
+    d.registerForDraggedTypes(types)
 
     vc.view.addSubview(d)
 
@@ -49,7 +52,7 @@ public class DesktopDropPlugin: NSObject, FlutterPlugin {
           let bookmarkByte = map["apple-bookmark"] as! FlutterStandardTypedData
           let bookmark = bookmarkByte.data
             
-            let url = try? URL(resolvingBookmarkData: bookmark, bookmarkDataIsStale: &isStale)
+            let url = try? URL(resolvingBookmarkData: bookmark, options: [.withSecurityScope], relativeTo: nil, bookmarkDataIsStale: &isStale)
             let suc = url?.startAccessingSecurityScopedResource()
             result(suc) 
             return
@@ -60,7 +63,7 @@ public class DesktopDropPlugin: NSObject, FlutterPlugin {
             var isStale: Bool = false 
           let bookmarkByte = map["apple-bookmark"] as! FlutterStandardTypedData
           let bookmark = bookmarkByte.data
-            let url = try? URL(resolvingBookmarkData: bookmark, bookmarkDataIsStale: &isStale)
+            let url = try? URL(resolvingBookmarkData: bookmark, options: [.withSecurityScope], relativeTo: nil, bookmarkDataIsStale: &isStale)
             url?.stopAccessingSecurityScopedResource()
             result(true)
             return
@@ -76,6 +79,7 @@ public class DesktopDropPlugin: NSObject, FlutterPlugin {
 
 class DropTarget: NSView {
   private let channel: FlutterMethodChannel
+  private let itemsLock = NSLock()
 
   init(frame frameRect: NSRect, channel: FlutterMethodChannel) {
     self.channel = channel
@@ -100,12 +104,17 @@ class DropTarget: NSView {
     channel.invokeMethod("exited", arguments: nil)
   }
 
-  /// Directory URL used for accepting file promises.
-  private lazy var destinationURL: URL = {
-    let destinationURL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("Drops")
-    try? FileManager.default.createDirectory(at: destinationURL, withIntermediateDirectories: true, attributes: nil)
-    return destinationURL
-  }()
+  /// Create a per-drop destination for promised files (avoids name collisions).
+  private func uniqueDropDestination() -> URL {
+    let base = FileManager.default.temporaryDirectory.appendingPathComponent("Drops", isDirectory: true)
+    let formatter = DateFormatter()
+    formatter.locale = Locale(identifier: "en_US_POSIX")
+    formatter.dateFormat = "yyyyMMdd_HHmmss_SSS'Z'"
+    let stamp = formatter.string(from: Date())
+    let dest = base.appendingPathComponent(stamp, isDirectory: true)
+    try? FileManager.default.createDirectory(at: dest, withIntermediateDirectories: true, attributes: nil)
+    return dest
+  }
 
   /// Queue used for reading and writing file promises.
   private lazy var workQueue: OperationQueue = {
@@ -114,40 +123,70 @@ class DropTarget: NSView {
     return providerQueue
   }()
 
-  override func performDragOperation(_ sender: NSDraggingInfo) -> Bool { 
-    var items: [[String: Any?]] = [];
-
-    let searchOptions: [NSPasteboard.ReadingOptionKey: Any] = [
-      .urlReadingFileURLsOnly: true,
-    ]
-
+  override func performDragOperation(_ sender: NSDraggingInfo) -> Bool {
+    let pb = sender.draggingPasteboard
+    let dest = uniqueDropDestination()
+    var items: [[String: Any]] = []
+    var seen = Set<String>()
     let group = DispatchGroup()
 
-    // retrieve NSFilePromise.
-    sender.enumerateDraggingItems(options: [], for: nil, classes: [NSFilePromiseReceiver.self, NSURL.self], searchOptions: searchOptions) { draggingItem, _, _ in
-      switch draggingItem.item {
-      case let filePromiseReceiver as NSFilePromiseReceiver:
-        group.enter()
-        filePromiseReceiver.receivePromisedFiles(atDestination: self.destinationURL, options: [:], operationQueue: self.workQueue) { fileURL, error in
-          if let error = error {
-            debugPrint("error: \(error)")
-          } else {
-              let data = try? fileURL.bookmarkData()
-          items.append([
-            "path":fileURL.path,
-            "apple-bookmark": data,
-          ])
+    func push(url: URL, fromPromise: Bool) {
+      let path = url.path
+      itemsLock.lock(); defer { itemsLock.unlock() }
+
+      // de-dupe safely under lock
+      if !seen.insert(path).inserted { return }
+
+      let values = try? url.resourceValues(forKeys: [.isDirectoryKey])
+      let isDirectory: Bool = values?.isDirectory ?? false
+
+      // Only create a security-scoped bookmark for items outside our container.
+      let bundleID = Bundle.main.bundleIdentifier ?? ""
+      let containerRoot = FileManager.default.homeDirectoryForCurrentUser
+        .appendingPathComponent("Library/Containers/\(bundleID)", isDirectory: true)
+        .path
+      let tmpPath = FileManager.default.temporaryDirectory.path
+      let isInsideContainer = path.hasPrefix(containerRoot) || path.hasPrefix(tmpPath)
+
+      let bmData: Any
+      if isInsideContainer {
+        bmData = NSNull()
+      } else {
+        let bm = try? url.bookmarkData(options: [.withSecurityScope], includingResourceValuesForKeys: nil, relativeTo: nil)
+        bmData = bm ?? NSNull()
+      }
+      items.append([
+        "path": path,
+        "apple-bookmark": bmData,
+        "isDirectory": isDirectory,
+        "fromPromise": fromPromise,
+      ])
+    }
+
+    // Prefer real file URLs if they exist; only fall back to promises
+    let urls = (pb.readObjects(forClasses: [NSURL.self], options: [.urlReadingFileURLsOnly: true]) as? [URL]) ?? []
+    let legacyList = (pb.propertyList(forType: NSPasteboard.PasteboardType("NSFilenamesPboardType")) as? [String]) ?? []
+
+    if !urls.isEmpty || !legacyList.isEmpty {
+      // 1) Modern file URLs
+      urls.forEach { push(url: $0, fromPromise: false) }
+      // 2) Legacy filename array used by some apps
+      legacyList.forEach { push(url: URL(fileURLWithPath: $0), fromPromise: false) }
+    } else {
+      // 3) Handle file promises (e.g., VS Code, browsers, Mail)
+      if let receivers = pb.readObjects(forClasses: [NSFilePromiseReceiver.self], options: nil) as? [NSFilePromiseReceiver],
+         !receivers.isEmpty {
+        for r in receivers {
+          group.enter()
+          r.receivePromisedFiles(atDestination: dest, options: [:], operationQueue: self.workQueue) { url, error in
+            defer { group.leave() }
+            if let error = error {
+              debugPrint("NSFilePromiseReceiver error: \(error)")
+              return
+            }
+            push(url: url, fromPromise: true)
           }
-          group.leave()
         }
-      case let fileURL as URL:
-          let data = try? fileURL.bookmarkData()
-          
-        items.append([
-          "path":fileURL.path,
-          "apple-bookmark": data,
-        ])
-      default: break
       }
     }
 
diff --git a/packages/desktop_drop/pubspec.yaml b/packages/desktop_drop/pubspec.yaml
@@ -1,6 +1,6 @@
 name: desktop_drop
 description: A plugin which allows user dragging files to your flutter desktop applications.
-version: 0.6.1
+version: 0.7.0
 homepage: https://github.com/MixinNetwork/flutter-plugins/tree/main/packages/desktop_drop
 
 environment:
@@ -19,7 +19,7 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  flutter_lints: ^5.0.0
+  flutter_lints: ^6.0.0
 
 flutter:
   plugin:

Original file line number	Diff line number	Diff line change
`@@ -6,7 +6,7 @@ import PackageDescription`
`6`	`6`	`let package = Package(`
`7`	`7`	`name: "desktop_drop",`
`8`	`8`	`platforms: [`
`9`		`- .macOS("10.11")`
	`9`	`+ .macOS("10.13")`
`10`	`10`	`],`
`11`	`11`	`products: [`
`12`	`12`	`.library(name: "desktop-drop", targets: ["desktop_drop"])`
`@@ -21,4 +21,4 @@ let package = Package(`
`21`	`21`	`]`
`22`	`22`	`)`
`23`	`23`	`]`
`24`		`-)`
	`24`	`+)`