Implement recursive watching of a directory

Package.resolved

@@ -1,5 +1,5 @@
 {
-  "originHash" : "db0ba74c125e968c67646390cbba012a5572a5c9c54171588ecbb73e370a448d",
+  "originHash" : "fd1e824e418c767633bb79b055a4e84d9c86165746bc881d5d27457ad34b0c20",
   "pins" : [
     {
       "identity" : "noora",
@@ -46,6 +46,15 @@
         "version" : "1.1.3"
       }
     },
+    {
+      "identity" : "swift-atomics",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-atomics.git",
+      "state" : {
+        "revision" : "b601256eab081c0f92f059e12818ac1d4f178ff7",
+        "version" : "1.3.0"
+      }
+    },
     {
       "identity" : "swift-collections",
       "kind" : "remoteSourceControl",
@@ -64,6 +73,15 @@
         "version" : "1.10.1"
       }
     },
+    {
+      "identity" : "swift-nio",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-nio",
+      "state" : {
+        "revision" : "e932d3c4d8f77433c8f7093b5ebcbf91463948a0",
+        "version" : "2.95.0"
+      }
+    },
     {
       "identity" : "swift-subprocess",
       "kind" : "remoteSourceControl",

Package.swift

@@ -18,6 +18,7 @@ let package = Package(
 		.package(url: "https://github.com/apple/swift-argument-parser", from: "1.7.0"),
 		.package(url: "https://github.com/apple/swift-async-algorithms", from: "1.1.3"),
 		.package(url: "https://github.com/apple/swift-log", from: "1.10.1"),
+		.package(url: "https://github.com/apple/swift-nio", from: "2.95.0"),
 		.package(url: "https://github.com/apple/swift-system", from: "1.6.4"),
 		.package(url: "https://github.com/swiftlang/swift-subprocess.git", from: "0.3.0"),
 		.package(url: "https://github.com/tuist/Noora", from: "0.55.1")
@@ -29,6 +30,7 @@ let package = Package(
 			dependencies: [
 				"CInotify",
 				.product(name: "Logging", package: "swift-log"),
+				.product(name: "_NIOFileSystem", package: "swift-nio"),
 				.product(name: "SystemPackage", package: "swift-system")
 			]
 		),

Sources/Inotify/DirectoryResolver.swift

@@ -0,0 +1,44 @@
+import _NIOFileSystem
+
+public struct DirectoryResolver {
+	static let fileManager = FileSystem.shared
+
+	public static func resolve(_ paths: String...) async throws -> [FilePath] {
+		try await Self.resolve(paths)
+	}
+
+	static func resolve(_ paths: [String]) async throws -> [FilePath] {
+		var resolved: [FilePath] = []
+
+		for path in paths {
+			let itemPath = FilePath(path)
+			try await Self.ensure(itemPath, is: .directory)
+
+			let allDirectoriesIncludingSelf = try await getAllSubdirectoriesAndSelf(at: itemPath)
+			resolved.append(contentsOf: allDirectoriesIncludingSelf)
+		}
+
+		return resolved
+	}
+
+	private static func ensure(_ path: FilePath, is fileType: FileType) async throws {
+		guard let fileInfo = try await fileManager.info(forFileAt: path) else {
+			throw DirectoryResolverError.pathNotFound(path)
+		}
+
+		guard fileInfo.type == fileType else {
+			throw DirectoryResolverError.pathIsNoDirectory(path)
+		}
+	}
+
+	private static func getAllSubdirectoriesAndSelf(at path: FilePath) async throws -> [FilePath] {
+		var result: [FilePath] = []
+		let directoryHandle = try await fileManager.openDirectory(atPath: path)
+		for try await childContent in directoryHandle.listContents(recursive: true) {
+			guard childContent.type == .directory else { continue }
+			result.append(childContent.path)
+		}
+		try await directoryHandle.close()
+		return result
+	}
+}

Sources/Inotify/DirectoryResolverErrror.swift

@@ -0,0 +1,16 @@
+import Foundation
+import SystemPackage
+
+public enum DirectoryResolverError: LocalizedError, Equatable {
+	case pathNotFound(FilePath)
+	case pathIsNoDirectory(FilePath)
+
+	var errorDescription: String {
+		switch self {
+		case .pathNotFound(let path):
+			return "Path not found: \(path)"
+		case .pathIsNoDirectory(let path):
+			return "Path is not a directory: \(path)"
+		}
+	}
+}

Sources/Inotify/Inotify.swift

@@ -28,6 +28,17 @@ public actor Inotify {
 		return wd
 	}
 
+	@discardableResult
+	public func addRecursiveWatch(forDirectory path: String, mask: InotifyEventMask) async throws -> [CInt] {
+		let directoryPaths = try await DirectoryResolver.resolve(path)
+		var result: [CInt] = []
+		for path in directoryPaths {
+			let wd = try self.addWatch(path: path.string, mask: mask)
+			result.append(wd)
+		}
+		return result
+	}
+
 	public func removeWatch(_ wd: CInt) throws {
 		guard inotify_rm_watch(self.fd, wd) == 0 else {
 			throw InotifyError.removeWatchFailed(watchDescriptor: wd, errno: cinotify_get_errno())

Tests/InotifyIntegrationTests/RecursiveEventTests.swift

@@ -0,0 +1,23 @@
+import Foundation
+import Testing
+@testable import Inotify
+
+@Suite("Recursive Event Detection")
+struct RecursiveEventTests {
+	@Test func detectsFileCreationInSubfolder() async throws {
+		try await withTempDir { dir in
+			let subDirectory = "\(dir)/Subfolder"
+			let filepath = "\(subDirectory)/modify-target.txt"
+			try FileManager.default.createDirectory(atPath: subDirectory, withIntermediateDirectories: true)
+
+			let events = try await getEventsForTrigger(
+				in: dir,
+				mask: [.create],
+				recursive: true
+			) { _ in try createFile(at: "\(filepath)", contents: "hello") }
+
+			let createEvent = events.first { $0.mask.contains(.create) && $0.path.string == filepath }
+			#expect(createEvent != nil, "Expected CREATE for '\(filepath)', got: \(events)")
+		}
+	}
+}

Tests/InotifyIntegrationTests/Utilities/getEventsForTrigger.swift

@@ -3,10 +3,15 @@ import Inotify
 func getEventsForTrigger(
 	in dir: String,
 	mask: InotifyEventMask,
-	trigger: @escaping (String) async throws -> Void
+	recursive: Bool = false,
+	trigger: @escaping (String) async throws -> Void,
 ) async throws -> [InotifyEvent] {
 	let watcher = try Inotify()
-	try await watcher.addWatch(path: dir, mask: mask)
+	if recursive {
+		try await watcher.addRecursiveWatch(forDirectory: dir, mask: mask)
+	} else {
+		try await watcher.addWatch(path: dir, mask: mask)
+	}
 
 	let eventTask = Task {
 		var events: [InotifyEvent] = []