Fixed progress reporting during file content decryption

Author: tobihagemann

CryptoLib/Cryptor.swift

@@ -231,8 +231,8 @@ public class Cryptor {
 			}
 			let ciphertextChunk = try encryptSingleChunk(cleartextChunk, chunkNumber: chunkNumber, headerNonce: header.nonce, fileKey: header.contentKey)
 			ciphertextStream.write(ciphertextChunk, maxLength: ciphertextChunk.count)
-			chunkNumber += 1
 			progress.completedUnitCount += Int64(ciphertextChunk.count)
+			chunkNumber += 1
 		}
 	}
 
@@ -272,7 +272,7 @@ public class Cryptor {
 	internal func decryptContent(from ciphertextStream: InputStream, to cleartextStream: OutputStream, ciphertextSize: Int?) throws {
 		// create progress:
 		let progress: Progress
-		if let ciphertextSize = ciphertextSize, let cleartextSize = try? calculateCleartextSize(ciphertextSize) {
+		if let ciphertextSize = ciphertextSize, let cleartextSize = try? calculateCleartextSize(ciphertextSize - Cryptor.fileHeaderSize) {
 			progress = Progress(totalUnitCount: Int64(cleartextSize))
 		} else {
 			progress = Progress(totalUnitCount: -1)
@@ -292,8 +292,8 @@ public class Cryptor {
 			}
 			let cleartextChunk = try decryptSingleChunk(ciphertextChunk, chunkNumber: chunkNumber, headerNonce: header.nonce, fileKey: header.contentKey)
 			cleartextStream.write(cleartextChunk, maxLength: cleartextChunk.count)
-			chunkNumber += 1
 			progress.completedUnitCount += Int64(cleartextChunk.count)
+			chunkNumber += 1
 		}
 	}
 

CryptoLibTests/CryptorTests.swift

@@ -99,8 +99,18 @@ class CryptorTests: XCTestCase {
 
 		let ciphertextURL = tmpDirURL.appendingPathComponent(UUID().uuidString, isDirectory: false)
 		let cleartextURL = tmpDirURL.appendingPathComponent(UUID().uuidString, isDirectory: false)
+		let overallProgress = Progress(totalUnitCount: 2)
+		let progressObserver = overallProgress.observe(\.fractionCompleted) { progress, _ in
+			print("\(progress.localizedDescription ?? "") (\(progress.localizedAdditionalDescription ?? ""))")
+		}
+		overallProgress.becomeCurrent(withPendingUnitCount: 1)
 		try cryptor.encryptContent(from: originalURL, to: ciphertextURL)
+		overallProgress.resignCurrent()
+		overallProgress.becomeCurrent(withPendingUnitCount: 1)
 		try cryptor.decryptContent(from: ciphertextURL, to: cleartextURL)
+		overallProgress.resignCurrent()
+		progressObserver.invalidate()
+		XCTAssertTrue(overallProgress.completedUnitCount >= overallProgress.totalUnitCount)
 
 		let cleartextData = try Data(contentsOf: cleartextURL)
 		XCTAssertEqual(originalData, cleartextData)

Podfile.lock

@@ -17,4 +17,4 @@ SPEC CHECKSUMS:
 
 PODFILE CHECKSUM: 026266d3146c90650716bef1229c141bb12d87b4
 
-COCOAPODS: 1.9.1
+COCOAPODS: 1.9.3