ref: simplify readEntitlements() + unzip to tmp-dir shortcut

src/Preview+Entitlements.swift

@@ -3,25 +3,22 @@ import Foundation
 extension PreviewGenerator {
 	/// Search for app binary and run `codesign` on it.
 	private func readEntitlements(_ meta: MetaInfo, _ bundleExecutable: String?) -> Entitlements {
-		guard let bundleExecutable else {
-			return Entitlements.withoutBinary()
-		}
-		
+		if let exe = bundleExecutable {
 			switch meta.type {
 			case .IPA:
-			let tmpPath = NSTemporaryDirectory() + "/" + UUID().uuidString
-			try! FileManager.default.createDirectory(atPath: tmpPath, withIntermediateDirectories: true)
+				if let tmpPath = try? meta.zipFile!.unzipFileToTempDir("Payload/*.app/\(exe)") {
 					defer {
 						try? FileManager.default.removeItem(atPath: tmpPath)
 					}
-			try! meta.zipFile!.unzipFile("Payload/*.app/\(bundleExecutable)", toDir: tmpPath)
-			return Entitlements(forBinary: tmpPath + "/" + bundleExecutable)
-		case .Archive, .Extension:
-			return Entitlements(forBinary: meta.effectiveUrl("MacOS", bundleExecutable).path)
-		case .APK:
-			// not applicable for Android
-			return Entitlements.withoutBinary()
+					return Entitlements(forBinary: tmpPath + "/" + exe)
 				}
+			case .Archive, .Extension:
+				return Entitlements(forBinary: meta.effectiveUrl("MacOS", exe).path)
+			case .APK:
+				break // not applicable for Android
+			}
+		}
+		return Entitlements.withoutBinary()
 	}
 	
 	/// Process compiled binary and provision plist to extract `Entitlements`

src/Zip.swift

@@ -354,12 +354,23 @@ struct ZipFile {
 	/// Unzip file to filesystem.
 	/// @param filePath File path inside zip file.
 	/// @param targetDir Directory in which to unzip the file.
-	func unzipFile(_ filePath: String, toDir targetDir: String) throws {
-		if let data = self.unzipFile(filePath) {
+	@discardableResult
+	func unzipFile(_ filePath: String, toDir targetDir: String) throws -> String? {
+		guard let data = self.unzipFile(filePath) else {
+			return nil
+		}
 		let filename = filePath.components(separatedBy: "/").last!
 		let outputPath = targetDir.appending("/" + filename)
 		os_log(.debug, log: log, "[unzip] write to %{public}@", outputPath)
 		try data.write(to: URL(fileURLWithPath: outputPath), options: .atomic)
+		return outputPath
 	}
+	
+	/// Extract selected `filePath` inside zip to a new temporary directory and return path to that file.
+	/// @return Path to extracted data. Returns `nil` or throws exception if data could not be extracted.
+	func unzipFileToTempDir(_ filePath: String) throws -> String? {
+		let tmpPath = NSTemporaryDirectory() + "/" + UUID().uuidString
+		try! FileManager.default.createDirectory(atPath: tmpPath, withIntermediateDirectories: true)
+		return try unzipFile(filePath, toDir: tmpPath)
 	}
 }