Improve JSON progress file handling and error reporting

Author: roulpriya

Sources/Swiftly/JsonFileProgressReporter.swift

@@ -11,27 +11,30 @@ enum ProgressInfo: Codable {
 struct JsonFileProgressReporter: ProgressAnimationProtocol {
     let filePath: FilePath
     private let encoder: JSONEncoder
+    private let ctx: SwiftlyCoreContext
+    private let fileHandle: FileHandle
 
-    init(filePath: FilePath, encoder: JSONEncoder = JSONEncoder()) {
+    init(_ ctx: SwiftlyCoreContext, filePath: FilePath, encoder: JSONEncoder = JSONEncoder()) throws
+    {
+        self.ctx = ctx
         self.filePath = filePath
         self.encoder = encoder
+        self.fileHandle = try FileHandle(forWritingTo: URL(fileURLWithPath: filePath.string))
     }
 
     private func writeProgress(_ progress: ProgressInfo) {
         let jsonData = try? self.encoder.encode(progress)
-        guard let jsonData = jsonData, let jsonString = String(data: jsonData, encoding: .utf8)
-        else {
-            print("Failed to encode progress entry to JSON")
+        guard let jsonData = jsonData else {
+            Task { [ctx = self.ctx] in
+                await ctx.message("Failed to encode progress entry to JSON")
+            }
             return
         }
 
-        let jsonLine = jsonString + "\n"
-
-        do {
-            try jsonLine.append(to: self.filePath)
-        } catch {
-            print("Failed to write progress entry to \(self.filePath): \(error)")
-        }
+        self.fileHandle.seekToEndOfFile()
+        self.fileHandle.write(jsonData)
+        self.fileHandle.write("\n".data(using: .utf8) ?? Data())
+        self.fileHandle.synchronizeFile()
     }
 
     func update(step: Int, total: Int, text: String) {
@@ -49,10 +52,11 @@ struct JsonFileProgressReporter: ProgressAnimationProtocol {
     }
 
     func clear() {
-        do {
-            try FileManager.default.removeItem(atPath: self.filePath.string)
-        } catch {
-            print("Failed to clear progress file at \(self.filePath): \(error)")
-        }
+        self.fileHandle.truncateFile(atOffset: 0)
+        self.fileHandle.synchronizeFile()
+    }
+
+    func close() throws {
+        try self.fileHandle.close()
     }
 }

Sources/SwiftlyCore/FileManager+FilePath.swift

@@ -195,15 +195,6 @@ extension String {
             try self.write(to: path, atomically: true, encoding: enc)
             return
         }
-
-        let fileHandle = try FileHandle(forWritingTo: URL(fileURLWithPath: path.string))
-        defer { fileHandle.closeFile() }
-        fileHandle.seekToEndOfFile()
-        if let data = self.data(using: enc) {
-            fileHandle.write(data)
-        } else {
-            throw SwiftlyError(message: "Failed to convert string to data with encoding \(enc)")
-        }
     }
 
     public init(contentsOf path: FilePath, encoding enc: String.Encoding = .utf8) throws {

Tests/SwiftlyTests/JsonFileProgressReporterTests.swift

@@ -1,6 +1,4 @@
 import Foundation
-@testable import Swiftly
-@testable import SwiftlyCore
 import SystemPackage
 import Testing
 
@@ -102,18 +100,21 @@ import Testing
         try FileManager.default.removeItem(atPath: tempFile.string)
     }
 
-    @Test("Test clear method removes file")
-    func testClearRemovesFile() throws {
+    @Test("Test clear method truncates the file")
+    func testClearTruncatesFile() async throws {
         let tempFile = fs.mktemp(ext: ".json")
-        let reporter = JsonFileProgressReporter(filePath: tempFile)
+        try await fs.create(.mode(Int(0o644)), file: tempFile)
+        defer { try? FileManager.default.removeItem(atPath: tempFile.string) }
+        let reporter = try JsonFileProgressReporter(SwiftlyTests.ctx, filePath: tempFile)
+        defer { try? reporter.close() }
 
         reporter.update(step: 1, total: 2, text: "Test")
 
-        #expect(FileManager.default.fileExists(atPath: tempFile.string))
+        #expect(try String(contentsOf: tempFile).lengthOfBytes(using: String.Encoding.utf8) > 0)
 
         reporter.clear()
 
-        #expect(!FileManager.default.fileExists(atPath: tempFile.string))
+        #expect(try String(contentsOf: tempFile).lengthOfBytes(using: String.Encoding.utf8) == 0)
     }
 
     @Test("Test multiple progress updates create multiple lines")