Add hasQuarantineAttribute to FileSystem (#411)

This new function returns `true` if a given path has a quarantine attribute applied if when file system supports this attribute, and returns `false` if such attribute is not applied or it isn't supported.

Sources/TSCBasic/FileSystem.swift

@@ -168,6 +168,10 @@ public protocol FileSystem: Sendable {
     /// Check whether the given path is accessible and writable.
     func isWritable(_ path: AbsolutePath) -> Bool
 
+    /// Returns `true` if a given path has a quarantine attribute applied if when file system supports this attribute.
+    /// Returns `false` if such attribute is not applied or it isn't supported.
+    func hasQuarantineAttribute(_ path: AbsolutePath) -> Bool
+
     // FIXME: Actual file system interfaces will allow more efficient access to
     // more data than just the name here.
     //
@@ -293,6 +297,8 @@ public extension FileSystem {
     func withLock<T>(on path: AbsolutePath, type: FileLock.LockType, _ body: () throws -> T) throws -> T {
         throw FileSystemError(.unsupported, path)
     }
+
+    func hasQuarantineAttribute(_ path: AbsolutePath) -> Bool { false }
 }
 
 /// Concrete FileSystem implementation which communicates with the local file system.
@@ -341,6 +347,16 @@ private struct LocalFileSystem: FileSystem {
         return FileInfo(attrs)
     }
 
+    func hasQuarantineAttribute(_ path: AbsolutePath) -> Bool {
+#if canImport(Darwin)
+        let bufLength = getxattr(path.pathString, "com.apple.quarantine", nil, 0, 0, 0)
+
+        return bufLength > 0
+#else
+        return false
+#endif
+    }
+
     var currentWorkingDirectory: AbsolutePath? {
         let cwdStr = FileManager.default.currentDirectoryPath
 

Tests/TSCBasicTests/FileSystemTests.swift

@@ -860,6 +860,19 @@ class FileSystemTests: XCTestCase {
         try _testFileSystemFileLock(fileSystem: fs, fileA: fileA, fileB: fileB, lockFile: lockFile)
     }
 
+#if canImport(Darwin)
+    func testQuarantineAttribute() throws {
+        try withTemporaryDirectory(removeTreeOnDeinit: true) { tempDir in
+            let filePath = tempDir.appending(component: "quarantined")
+            try localFileSystem.writeFileContents(filePath, bytes: "")
+            try Process.checkNonZeroExit(args: "xattr", "-w", "com.apple.quarantine", "foo", filePath.pathString)
+            XCTAssertTrue(localFileSystem.hasQuarantineAttribute(filePath))
+            try Process.checkNonZeroExit(args: "xattr", "-d", "com.apple.quarantine", filePath.pathString)
+            XCTAssertFalse(localFileSystem.hasQuarantineAttribute(filePath))
+        }
+    }
+#endif
+
     private func _testFileSystemFileLock(fileSystem fs: FileSystem, fileA: AbsolutePath, fileB: AbsolutePath, lockFile: AbsolutePath) throws {
         // write initial value, since reader may start before writers and files would not exist
         try fs.writeFileContents(fileA, bytes: "0")