[ios] implement logging to the file

- get logs from core
- log them in the default os_log to see in the Console app
- write to file

Signed-off-by: Kiryl Kaveryn <kirylkaveryn@gmail.com>

iphone/CoreApi/CoreApi/Logger/Logger.h

@@ -12,8 +12,11 @@ typedef NS_ENUM(NSUInteger, LogLevel) {
 
 @interface Logger : NSObject
 
-+ (void)log:(LogLevel)level message:(NSString*)message;
++ (void)log:(LogLevel)level message:(NSString *)message;
 + (BOOL)canLog:(LogLevel)level;
++ (void)setFileLoggingEnabled:(BOOL)fileLoggingEnabled;
++ (nullable NSURL *)getLogFileURL;
++ (uint64_t)getLogFileSize;
 
 @end
 

iphone/CoreApi/CoreApi/Logger/Logger.mm

@@ -1,32 +1,249 @@
 #import "Logger.h"
-#import "base/logging.hpp"
+#import <OSLog/OSLog.h>
+
+#include "base/logging.hpp"
+#include "coding/zip_creator.hpp"
 
 @interface Logger ()
+
+@property (nullable, nonatomic) NSFileHandle * fileHandle;
+@property (nonnull, nonatomic) os_log_t osLogger;
+/// This property is introduced to avoid the CoreApi => Maps target dependency and stores the MWMSettings.isFileLoggingEnabled value.
+@property (class, nonatomic) BOOL fileLoggingEnabled;
+@property (class, readonly, nonatomic) dispatch_queue_t fileLoggingQueue;
+
++ (Logger *)logger;
++ (void)enableFileLogging;
++ (void)disableFileLogging;
++ (void)logMessageWithLevel:(base::LogLevel)level src:(base::SrcPoint const &)src message:(std::string const &)message;
++ (NSURL *)getZippedLogFile:(NSString *)logFilePath;
++ (void)removeFileAtPath:(NSString *)filePath;
 + (base::LogLevel)baseLevel:(LogLevel)level;
+
 @end
 
+// Subsystem and category are used for the OSLog.
+NSString * const kLoggerSubsystem = [[NSBundle mainBundle] bundleIdentifier];
+NSString * const kLoggerCategory = @"OM";
+NSString * const kLogFileName = @"log.txt";
+NSString * const kZipLogFileExtension = @"zip";
+NSString * const kLogFilePath = [[NSFileManager.defaultManager temporaryDirectory] URLByAppendingPathComponent:kLogFileName].path;
+// TODO: (KK) Review and change this limit after some testing.
+NSUInteger const kMaxLogFileSize = 1024 * 1024 * 100; // 100 MB;
+
 @implementation Logger
 
-+ (void)log:(LogLevel)level message:(NSString*)message {
-  LOG_SHORT([Logger baseLevel:level], (message.UTF8String));
+static BOOL _fileLoggingEnabled = NO;
+
++ (void)initialize
+{
+  if (self == [Logger class]) {
+    SetLogMessageFn(&LogMessage);
+    SetAssertFunction(&AssertMessage);
+  }
+}
+
++ (Logger *)logger {
+  static Logger * logger = nil;
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    logger = [[self alloc] init];
+  });
+  return logger;
+}
+
++ (dispatch_queue_t)fileLoggingQueue {
+  static dispatch_queue_t fileLoggingQueue = nil;
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    dispatch_queue_attr_t attributes = dispatch_queue_attr_make_with_qos_class(DISPATCH_QUEUE_SERIAL, QOS_CLASS_UTILITY, 0);
+    fileLoggingQueue = dispatch_queue_create("app.organicmaps.fileLoggingQueue", attributes);
+  });
+  return fileLoggingQueue;
+}
+
+- (instancetype)init {
+  self = [super init];
+  if (self) {
+    _osLogger = os_log_create(kLoggerSubsystem.UTF8String, kLoggerCategory.UTF8String);
+  }
+  return self;
+}
+
+// MARK: - Public
+
++ (void)setFileLoggingEnabled:(BOOL)fileLoggingEnabled {
+  fileLoggingEnabled ? [self enableFileLogging] : [self disableFileLogging];
+}
+
++ (BOOL)fileLoggingEnabled {
+  return _fileLoggingEnabled;
+}
+
++ (void)log:(LogLevel)level message:(NSString *)message {
+  LOG_SHORT([self baseLevel:level], (message.UTF8String));
 }
 
 + (BOOL)canLog:(LogLevel)level {
   return [Logger baseLevel:level] >= base::g_LogLevel;
 }
 
++ (nullable NSURL *)getLogFileURL {
+  if ([self fileLoggingEnabled]) {
+    if (![NSFileManager.defaultManager fileExistsAtPath:kLogFilePath]) {
+      LOG(LERROR, ("Log file doesn't exist while file logging is enabled:", kLogFilePath.UTF8String));
+      return nil;
+    }
+    return [self getZippedLogFile:kLogFilePath];
+  } else {
+    // Fetch logs from the OSLog store.
+    if (@available(iOS 15.0, *)) {
+      NSError * error;
+      OSLogStore * store = [OSLogStore storeWithScope:OSLogStoreCurrentProcessIdentifier error:&error];
+
+      if (error) {
+        LOG(LERROR, (error.localizedDescription.UTF8String));
+        return nil;
+      }
+
+      NSPredicate * predicate = [NSPredicate predicateWithFormat:@"subsystem == %@", kLoggerSubsystem];
+      OSLogEnumerator * enumerator = [store entriesEnumeratorWithOptions:{} position:nil predicate:predicate error:&error];
+
+      if (error) {
+        LOG(LERROR, (error.localizedDescription.UTF8String));
+        return nil;
+      }
+
+      NSMutableString * logString = [NSMutableString string];
+      NSString * kNewLineStr = @"\n";
+
+      id object;
+      while (object = [enumerator nextObject]) {
+        if ([object isMemberOfClass:[OSLogEntryLog class]]) {
+          [logString appendString:[object composedMessage]];
+          [logString appendString:kNewLineStr];
+        }
+      }
+
+      if (logString.length == 0) {
+        LOG(LINFO, ("OSLog entry is empty."));
+        return nil;
+      }
+
+      [NSFileManager.defaultManager createFileAtPath:kLogFilePath contents:[logString dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];
+      return [self getZippedLogFile:kLogFilePath];
+    } else {
+      return nil;
+    }
+  }
+}
+
++ (uint64_t)getLogFileSize {
+  Logger * logger = [self logger];
+  return logger.fileHandle != nil ? [logger.fileHandle offsetInFile] : 0;
+}
+
+// MARK: - C++ injection
+
+void LogMessage(base::LogLevel level, base::SrcPoint const & src, std::string const & message)
+{
+  [Logger logMessageWithLevel:level src:src message:message];
+  CHECK_LESS(level, base::g_LogAbortLevel, ("Abort. Log level is too serious", level));
+}
+
+bool AssertMessage(base::SrcPoint const & src, std::string const & message)
+{
+  [Logger logMessageWithLevel:base::LCRITICAL src:src message:message];
+  return true;
+}
+
+// MARK: - Private
+
++ (void)enableFileLogging {
+  Logger * logger = [self logger];
+  NSFileManager * fileManager = [NSFileManager defaultManager];
+
+  // Create a log file if it doesn't exist and setup file handle for writing.
+  if (![fileManager fileExistsAtPath:kLogFilePath])
+    [fileManager createFileAtPath:kLogFilePath contents:nil attributes:nil];
+  NSFileHandle * fileHandle = [NSFileHandle fileHandleForWritingAtPath:kLogFilePath];
+  if (fileHandle == nil) {
+    LOG(LERROR, ("Failed to open log file for writing", kLogFilePath.UTF8String));
+    [self disableFileLogging];
+    return;
+  }
+  // Clean up the file if it exceeds the maximum size.
+  if ([fileManager contentsAtPath:kLogFilePath].length > kMaxLogFileSize)
+    [fileHandle truncateFileAtOffset:0];
+
+  logger.fileHandle = fileHandle;
+
+  _fileLoggingEnabled = YES;
+  LOG(LINFO, ("File logging is enabled"));
+}
+
++ (void)disableFileLogging {
+  Logger * logger = [self logger];
+
+  [logger.fileHandle closeFile];
+  logger.fileHandle = nil;
+  [self removeFileAtPath:kLogFilePath];
+
+  _fileLoggingEnabled = NO;
+  LOG(LINFO, ("File logging is disabled"));
+}
+
++ (void)logMessageWithLevel:(base::LogLevel)level src:(base::SrcPoint const &)src message:(std::string const &)message {
+  // Build the log message string.
+  auto & logHelper = base::LogHelper::Instance();
+  std::ostringstream output;
+  // TODO: (KK) Either guard this call, or refactor thread ids in logHelper.
+  logHelper.WriteProlog(output, level);
+  logHelper.WriteLog(output, src, message);
+  
+  auto const logString = output.str();
+
+  Logger * logger = [self logger];
+  // Log the message into the system log.
+  os_log(logger.osLogger, "%{public}s", logString.c_str());
+
+  dispatch_async([self fileLoggingQueue], ^{
+    // Write the log message into the file.
+    NSFileHandle * fileHandle = logger.fileHandle;
+    if (fileHandle != nil) {
+      [fileHandle seekToEndOfFile];
+      [fileHandle writeData:[NSData dataWithBytes:logString.c_str() length:logString.length()]];
+    }
+  });
+}
+
++ (NSURL *)getZippedLogFile:(NSString *)logFilePath {
+  NSString * zipFilePath = [[logFilePath stringByDeletingPathExtension] stringByAppendingPathExtension:kZipLogFileExtension];
+  auto const success = CreateZipFromFiles({logFilePath.UTF8String}, zipFilePath.UTF8String);
+  if (!success) {
+    LOG(LERROR, ("Failed to zip log file:", kLogFilePath.UTF8String, ". The original file will be returned."));
+    return [NSURL fileURLWithPath:logFilePath];
+  }
+  [self removeFileAtPath:kLogFilePath];
+  return [NSURL fileURLWithPath:zipFilePath];
+}
+
++ (void)removeFileAtPath:(NSString *)filePath {
+  if ([NSFileManager.defaultManager fileExistsAtPath:filePath]) {
+    NSError * error;
+    [NSFileManager.defaultManager removeItemAtPath:filePath error:&error];
+    if (error)
+      LOG(LERROR, (error.localizedDescription.UTF8String));
+  }
+}
+
 + (base::LogLevel)baseLevel:(LogLevel)level {
   switch (level) {
-    case LogLevelDebug:
-      return LDEBUG;
-    case LogLevelInfo:
-      return LINFO;
-    case LogLevelWarning:
-      return LWARNING;
-    case LogLevelError:
-      return LERROR;
-    case LogLevelCritical:
-      return LCRITICAL;
+    case LogLevelDebug: return LDEBUG;
+    case LogLevelInfo: return LINFO;
+    case LogLevelWarning: return LWARNING;
+    case LogLevelError: return LERROR;
+    case LogLevelCritical: return LCRITICAL;
   }
 }
 

iphone/Maps/Common/Common.swift

@@ -1,5 +1,4 @@
 import Foundation
-import OSLog
 
 private func IPAD() -> Bool { return UI_USER_INTERFACE_IDIOM() == .pad }
 
@@ -28,42 +27,18 @@ func statusBarHeight() -> CGFloat {
   return min(statusBarSize.height, statusBarSize.width)
 }
 
-private let enableLoggingInRelease = true
-
 func LOG(_ level: LogLevel,
          _ message: @autoclosure () -> Any,
          functionName: StaticString = #function,
          fileName: StaticString = #file,
          lineNumber: UInt = #line) {
-
-  let shortFileName = URL(string: "\(fileName)")?.lastPathComponent ?? ""
-  let formattedMessage = "\(shortFileName):\(lineNumber) \(functionName): \(message())"
-
-  if #available(iOS 14.0, *), enableLoggingInRelease {
-    os.Logger.logger.log(level: OSLogLevelFromLogLevel(level), "\(formattedMessage, privacy: .public)")
-  } else if Logger.canLog(level) {
+  if (Logger.canLog(level)) {
+    let shortFileName = URL(string: "\(fileName)")?.lastPathComponent ?? ""
+    let formattedMessage = "\(shortFileName):\(lineNumber) \(functionName): \(message())"
     Logger.log(level, message: formattedMessage)
   }
 }
 
-private func OSLogLevelFromLogLevel(_ level: LogLevel) -> OSLogType {
-  switch level {
-  case .error: return .error
-  case .info: return .info
-  case .debug: return .debug
-  case .critical: return .fault
-  case .warning: return .default
-  @unknown default:
-    fatalError()
-  }
-}
-
 struct Weak<T> where T: AnyObject {
   weak var value: T?
 }
-
-@available(iOS 14.0, *)
-private extension os.Logger {
-  static let subsystem = Bundle.main.bundleIdentifier!
-  static let logger = Logger(subsystem: subsystem, category: "OM")
-}

iphone/Maps/Core/Settings/MWMSettings.h

@@ -37,4 +37,8 @@ NS_SWIFT_NAME(Settings)
 + (BOOL)iCLoudSynchronizationEnabled;
 + (void)setICLoudSynchronizationEnabled:(BOOL)iCLoudSyncEnabled;
 
++ (void)initializeLogging;
++ (BOOL)isFileLoggingEnabled;
++ (void)setFileLoggingEnabled:(BOOL)fileLoggingEnabled;
+
 @end

iphone/Maps/Core/Settings/MWMSettings.mm

@@ -3,8 +3,8 @@
 #import "MWMMapViewControlsManager.h"
 #import "SwiftBridge.h"
 
-
 #include <CoreApi/Framework.h>
+#include <CoreApi/Logger.h>
 
 namespace
 {
@@ -19,6 +19,7 @@ NSString * const kThemeMode = @"ThemeMode";
 NSString * const kSpotlightLocaleLanguageId = @"SpotlightLocaleLanguageId";
 NSString * const kUDTrackWarningAlertWasShown = @"TrackWarningAlertWasShown";
 NSString * const kiCLoudSynchronizationEnabledKey = @"iCLoudSynchronizationEnabled";
+NSString * const kUDFileLoggingEnabledKey = @"FileLoggingEnabledKey";
 }  // namespace
 
 @implementation MWMSettings
@@ -167,4 +168,21 @@ NSString * const kiCLoudSynchronizationEnabledKey = @"iCLoudSynchronizationEnabl
   [NSUserDefaults.standardUserDefaults setBool:iCLoudSyncEnabled forKey:kiCLoudSynchronizationEnabledKey];
   [NSNotificationCenter.defaultCenter postNotificationName:NSNotification.iCloudSynchronizationDidChangeEnabledState object:nil];
 }
+
++ (void)initializeLogging {
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    [self setFileLoggingEnabled:[self isFileLoggingEnabled]];
+  });
+}
+
++ (BOOL)isFileLoggingEnabled {
+  return [NSUserDefaults.standardUserDefaults boolForKey:kUDFileLoggingEnabledKey];
+}
+
++ (void)setFileLoggingEnabled:(BOOL)fileLoggingEnabled {
+  [NSUserDefaults.standardUserDefaults setBool:fileLoggingEnabled forKey:kUDFileLoggingEnabledKey];
+  [Logger setFileLoggingEnabled:fileLoggingEnabled];
+}
+
 @end

iphone/Maps/Maps.xcodeproj/project.pbxproj

@@ -482,6 +482,7 @@
 		ED79A5D72BDF8D6100952D1F /* SynchronizationStateManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = ED79A5CF2BDF8D6100952D1F /* SynchronizationStateManager.swift */; };
 		ED79A5D82BDF8D6100952D1F /* DefaultLocalDirectoryMonitor.swift in Sources */ = {isa = PBXBuildFile; fileRef = ED79A5D02BDF8D6100952D1F /* DefaultLocalDirectoryMonitor.swift */; };
 		ED7CCC4F2C1362E300E2A737 /* FileType.swift in Sources */ = {isa = PBXBuildFile; fileRef = ED7CCC4E2C1362E300E2A737 /* FileType.swift */; };
+		ED8270F02C2071A3005966DA /* SettingsTableViewDetailedSwitchCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = ED8270EF2C2071A3005966DA /* SettingsTableViewDetailedSwitchCell.swift */; };
 		ED9966802B94FBC20083CE55 /* ColorPicker.swift in Sources */ = {isa = PBXBuildFile; fileRef = ED99667D2B94FBC20083CE55 /* ColorPicker.swift */; };
 		EDBD68072B625724005DD151 /* LocationServicesDisabledAlert.xib in Resources */ = {isa = PBXBuildFile; fileRef = EDBD68062B625724005DD151 /* LocationServicesDisabledAlert.xib */; };
 		EDBD680B2B62572E005DD151 /* LocationServicesDisabledAlert.swift in Sources */ = {isa = PBXBuildFile; fileRef = EDBD680A2B62572E005DD151 /* LocationServicesDisabledAlert.swift */; };
@@ -1394,6 +1395,7 @@
 		ED79A5CF2BDF8D6100952D1F /* SynchronizationStateManager.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SynchronizationStateManager.swift; sourceTree = "<group>"; };
 		ED79A5D02BDF8D6100952D1F /* DefaultLocalDirectoryMonitor.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DefaultLocalDirectoryMonitor.swift; sourceTree = "<group>"; };
 		ED7CCC4E2C1362E300E2A737 /* FileType.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FileType.swift; sourceTree = "<group>"; };
+		ED8270EF2C2071A3005966DA /* SettingsTableViewDetailedSwitchCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SettingsTableViewDetailedSwitchCell.swift; sourceTree = "<group>"; };
 		ED99667D2B94FBC20083CE55 /* ColorPicker.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ColorPicker.swift; sourceTree = "<group>"; };
 		EDBD68062B625724005DD151 /* LocationServicesDisabledAlert.xib */ = {isa = PBXFileReference; lastKnownFileType = file.xib; path = LocationServicesDisabledAlert.xib; sourceTree = "<group>"; };
 		EDBD680A2B62572E005DD151 /* LocationServicesDisabledAlert.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocationServicesDisabledAlert.swift; sourceTree = "<group>"; };
@@ -3726,6 +3728,7 @@
 				F6E2FD381E097BA00083EBEC /* SettingsTableViewLinkCell.swift */,
 				F6E2FD391E097BA00083EBEC /* SettingsTableViewSelectableCell.swift */,
 				F6E2FD3A1E097BA00083EBEC /* SettingsTableViewSwitchCell.swift */,
+				ED8270EF2C2071A3005966DA /* SettingsTableViewDetailedSwitchCell.swift */,
 			);
 			path = Cells;
 			sourceTree = "<group>";
@@ -4445,6 +4448,7 @@
 				3454D7C21E07F045004AF2AD /* NSString+Categories.m in Sources */,
 				34E7761F1F14DB48003040B3 /* PlacePageArea.swift in Sources */,
 				ED79A5D82BDF8D6100952D1F /* DefaultLocalDirectoryMonitor.swift in Sources */,
+				ED8270F02C2071A3005966DA /* SettingsTableViewDetailedSwitchCell.swift in Sources */,
 				4728F69322CF89A400E00028 /* GradientView.swift in Sources */,
 				F6381BF61CD12045004CA943 /* LocaleTranslator.mm in Sources */,
 				9917D17F2397B1D600A7E06E /* IPadModalPresentationController.swift in Sources */,

iphone/Maps/UI/Help/AboutController/AboutController.swift

@@ -1,3 +1,5 @@
+import OSLog
+
 final class AboutController: MWMViewController {
 
   fileprivate struct AboutInfoTableViewCellModel {
@@ -276,7 +278,13 @@ private extension AboutController {
           self?.navigationController?.pushViewController(FaqController(), animated: true)
         case .reportABug:
           guard let link = aboutInfo.link else { fatalError("The recipient link should be provided to report a bug.") }
-          self?.sendEmailWith(header: "Organic Maps Bugreport", toRecipients: [link])
+          UIApplication.shared.showLoadingOverlay {
+            let logFileURL = Logger.getLogFileURL()
+            UIApplication.shared.hideLoadingOverlay {
+              guard let self else { return }
+              self.sendEmailWith(header: "Organic Maps Bugreport", toRecipients: [link], attachmentFileURL: logFileURL)
+            }
+          }
         case .reportMapDataProblem, .volunteer, .news:
           self?.openUrl(aboutInfo.link)
         case .rateTheApp:
@@ -436,7 +444,7 @@ extension AboutController: UICollectionViewDelegateFlowLayout {
 
 // MARK: - Mail Composing
 private extension AboutController {
-  func sendEmailWith(header: String, toRecipients: [String]) {
+  func sendEmailWith(header: String, toRecipients: [String], attachmentFileURL: URL? = nil) {
     func emailSubject(subject: String) -> String {
       let appInfo = AppInfo.shared()
       return String(format:"[%@-%@ iOS] %@", appInfo.bundleVersion, appInfo.buildNumber, subject)
@@ -496,9 +504,34 @@ private extension AboutController {
       return false
     }
 
+    func showMailComposingAlert() {
+      let text = String(format:L("email_error_body"), toRecipients.joined(separator: ";"))
+      let alert = UIAlertController(title: L("email_error_title"), message: text, preferredStyle: .alert)
+      let action = UIAlertAction(title: L("ok"), style: .default, handler: nil)
+      alert.addAction(action)
+      present(alert, animated: true, completion: nil)
+    }
+
     let subject = emailSubject(subject: header)
     let body = emailBody()
 
+    // If the attachment file path is provided, the default mail composer should be used.
+    if let attachmentFileURL {
+      if MWMMailViewController.canSendMail(), let attachmentData = try? Data(contentsOf: attachmentFileURL) {
+        let mailViewController = MWMMailViewController()
+        mailViewController.mailComposeDelegate = self
+        mailViewController.setSubject(subject)
+        mailViewController.setMessageBody(body, isHTML:false)
+        mailViewController.setToRecipients(toRecipients)
+        mailViewController.addAttachmentData(attachmentData, mimeType: "application/zip", fileName: attachmentFileURL.lastPathComponent)
+
+        self.present(mailViewController, animated: true, completion:nil)
+      } else {
+        showMailComposingAlert()
+      }
+      return
+    }
+
     // Before iOS 14, try to open alternate email apps first, assuming that if users installed them, they're using them.
     let os = ProcessInfo().operatingSystemVersion
     if (os.majorVersion < 14 && (openGmail(subject: subject, body: body, recipients: toRecipients) ||
@@ -507,14 +540,8 @@ private extension AboutController {
     }
     
     // From iOS 14, it is possible to change the default mail app, and mailto should open a default mail app.
-    if openDefaultMailApp(subject: subject, body: body, recipients: toRecipients) {
-      return
-    } else {
-      let text = String(format:L("email_error_body"), toRecipients.joined(separator: ";"))
-      let alert = UIAlertController(title: L("email_error_title"), message: text, preferredStyle: .alert)
-      let action = UIAlertAction(title: L("ok"), style: .default, handler: nil)
-      alert.addAction(action)
-      present(alert, animated: true, completion: nil)
+    if !openDefaultMailApp(subject: subject, body: body, recipients: toRecipients) {
+      showMailComposingAlert()
     }
   }
 }
@@ -537,3 +564,10 @@ private extension UIStackView {
     addArrangedSubview(view)
   }
 }
+
+// MARK: - MFMailComposeViewControllerDelegate
+extension AboutController: MFMailComposeViewControllerDelegate {
+  func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
+    dismiss(animated: true, completion: nil)
+  }
+}

iphone/Maps/UI/Settings/Cells/SettingsTableViewDetailedSwitchCell.swift

@@ -0,0 +1,20 @@
+class SettingsTableViewDetailedSwitchCell: SettingsTableViewSwitchCell {
+
+  override func awakeFromNib() {
+    super.awakeFromNib()
+    styleDetail()
+  }
+
+  @objc
+  func setDetail(_ text: String?) {
+    detailTextLabel?.text = text
+    setNeedsLayout()
+  }
+
+  private func styleDetail() {
+    let detailTextLabelStyle = "regular12:blackSecondaryText"
+    detailTextLabel?.setStyleAndApply(detailTextLabelStyle)
+    detailTextLabel?.numberOfLines = 0
+    detailTextLabel?.lineBreakMode = .byWordWrapping
+  }
+}

iphone/Maps/UI/Settings/Cells/SettingsTableViewiCloudSwitchCell.swift

@@ -1,9 +1,4 @@
-final class SettingsTableViewiCloudSwitchCell: SettingsTableViewSwitchCell {
-
-  override func awakeFromNib() {
-    super.awakeFromNib()
-    styleDetail()
-  }
+final class SettingsTableViewiCloudSwitchCell: SettingsTableViewDetailedSwitchCell {
 
   @objc
   func updateWithError(_ error: NSError?) {
@@ -24,11 +19,4 @@ final class SettingsTableViewiCloudSwitchCell: SettingsTableViewSwitchCell {
     }
     setNeedsLayout()
   }
-
-  private func styleDetail() {
-    let detailTextLabelStyle = "regular12:blackSecondaryText"
-    detailTextLabel?.setStyleAndApply(detailTextLabelStyle)
-    detailTextLabel?.numberOfLines = 0
-    detailTextLabel?.lineBreakMode = .byWordWrapping
-  }
 }

iphone/Maps/UI/Settings/MWMSettingsViewController.mm

@@ -33,7 +33,7 @@ static NSString * const kUDDidShowICloudSynchronizationEnablingAlert = @"kUDDidS
 @property(weak, nonatomic) IBOutlet SettingsTableViewLinkCell *voiceInstructionsCell;
 @property(weak, nonatomic) IBOutlet SettingsTableViewLinkCell *drivingOptionsCell;
 @property(weak, nonatomic) IBOutlet SettingsTableViewiCloudSwitchCell *iCloudSynchronizationCell;
-
+@property(weak, nonatomic) IBOutlet SettingsTableViewDetailedSwitchCell *enableLoggingCell;
 
 @end
 
@@ -189,9 +189,21 @@ static NSString * const kUDDidShowICloudSynchronizationEnablingAlert = @"kUDDidS
   [self.iCloudSynchronizationCell configWithDelegate:self
                                                title:@"iCloud Synchronization (Beta)"
                                                 isOn:isICLoudSynchronizationEnabled];
+
+  __weak __typeof(self) weakSelf = self;
   [CloudStorageManager.shared addObserver:self onErrorCompletionHandler:^(NSError * _Nullable error) {
-    [self.iCloudSynchronizationCell updateWithError:error];
+    __strong auto strongSelf = weakSelf;
+    [strongSelf.iCloudSynchronizationCell updateWithError:error];
   }];
+
+  [self.enableLoggingCell configWithDelegate:self title:L(@"enable_logging") isOn:MWMSettings.isFileLoggingEnabled];
+  [self updateLogFileSize];
+}
+
+- (void)updateLogFileSize {
+  uint64_t logFileSize = [Logger getLogFileSize];
+  NSString * detailString = logFileSize == 0 ? nil : [NSString stringWithFormat:L(@"log_file_size"), formattedSize(logFileSize)];
+  [self.enableLoggingCell setDetail:detailString];
 }
 
 - (void)show3dBuildingsAlert:(UITapGestureRecognizer *)recognizer {
@@ -324,6 +336,9 @@ static NSString * const kUDDidShowICloudSynchronizationEnablingAlert = @"kUDDidS
     } else {
       [MWMSettings setICLoudSynchronizationEnabled:value];
     }
+  } else if (cell == self.enableLoggingCell) {
+    [MWMSettings setFileLoggingEnabled:value];
+    [self updateLogFileSize];
   }
 }
 
@@ -373,4 +388,13 @@ static NSString * const kUDDidShowICloudSynchronizationEnablingAlert = @"kUDDidS
   }
 }
 
+- (NSString *)tableView:(UITableView *)tableView titleForFooterInSection:(NSInteger)section {
+  switch (section) {
+    case 1:
+      return L(@"enable_logging_warning_message");
+    default:
+      return nil;
+  }
+}
+
 @end

iphone/Maps/UI/Storyboard/Settings.storyboard

@@ -1,9 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="22505" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES">
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="32700.99.1234" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES">
     <device id="retina6_1" orientation="portrait" appearance="light"/>
     <dependencies>
         <deployment identifier="iOS"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="22504"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="22685"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <scenes>
@@ -292,7 +292,7 @@
                                             <autoresizingMask key="autoresizingMask"/>
                                             <subviews>
                                                 <label opaque="NO" multipleTouchEnabled="YES" contentMode="left" insetsLayoutMarginsFromSafeArea="NO" text="iCloud Synchronization (Beta)" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" id="QEX-D4-ejR">
-                                                    <rect key="frame" x="20" y="0.0" width="374" height="44"/>
+                                                    <rect key="frame" x="20" y="6" width="169" height="14.5"/>
                                                     <autoresizingMask key="autoresizingMask"/>
                                                     <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                                                     <fontDescription key="fontDescription" type="system" pointSize="0.0"/>
@@ -309,12 +309,37 @@
                                             </subviews>
                                         </tableViewCellContentView>
                                     </tableViewCell>
+                                    <tableViewCell contentMode="scaleToFill" selectionStyle="none" hidesAccessoryWhenEditing="NO" indentationLevel="1" indentationWidth="0.0" reuseIdentifier="SettingsTableViewDetailedSwitchCell" textLabel="IuW-8X-Xdf" detailTextLabel="dON-be-sur" style="IBUITableViewCellStyleSubtitle" id="uxV-uf-u44" userLabel="EnadbleLogging" customClass="SettingsTableViewDetailedSwitchCell" customModule="Organic_Maps" customModuleProvider="target">
+                                        <rect key="frame" x="0.0" y="630" width="414" height="44"/>
+                                        <autoresizingMask key="autoresizingMask"/>
+                                        <tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" tableViewCell="uxV-uf-u44" id="uwY-wf-q0J">
+                                            <rect key="frame" x="0.0" y="0.0" width="414" height="44"/>
+                                            <autoresizingMask key="autoresizingMask"/>
+                                            <subviews>
+                                                <label opaque="NO" multipleTouchEnabled="YES" contentMode="left" insetsLayoutMarginsFromSafeArea="NO" text="SendBugReport" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" id="IuW-8X-Xdf">
+                                                    <rect key="frame" x="20" y="6" width="89.5" height="14.5"/>
+                                                    <autoresizingMask key="autoresizingMask"/>
+                                                    <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                                                    <fontDescription key="fontDescription" type="system" pointSize="0.0"/>
+                                                    <nil key="textColor"/>
+                                                    <nil key="highlightedColor"/>
+                                                </label>
+                                                <label opaque="NO" multipleTouchEnabled="YES" contentMode="left" insetsLayoutMarginsFromSafeArea="NO" text="Subtitle" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" id="dON-be-sur">
+                                                    <rect key="frame" x="20" y="22.5" width="44" height="14.5"/>
+                                                    <autoresizingMask key="autoresizingMask"/>
+                                                    <fontDescription key="fontDescription" type="system" pointSize="0.0"/>
+                                                    <nil key="textColor"/>
+                                                    <nil key="highlightedColor"/>
+                                                </label>
+                                            </subviews>
+                                        </tableViewCellContentView>
+                                    </tableViewCell>
                                 </cells>
                             </tableViewSection>
                             <tableViewSection headerTitle="НАВИГАЦИЯ" id="E4E-hs-9xW">
                                 <cells>
                                     <tableViewCell contentMode="scaleToFill" selectionStyle="none" hidesAccessoryWhenEditing="NO" indentationLevel="1" indentationWidth="0.0" reuseIdentifier="SettingsTableViewSwitchCell" textLabel="E7d-pi-YM1" style="IBUITableViewCellStyleDefault" id="X5R-fv-yd7" customClass="SettingsTableViewSwitchCell" customModule="Organic_Maps" customModuleProvider="target">
-                                        <rect key="frame" x="0.0" y="634" width="414" height="44"/>
+                                        <rect key="frame" x="0.0" y="722" width="414" height="44"/>
                                         <autoresizingMask key="autoresizingMask"/>
                                         <tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" tableViewCell="X5R-fv-yd7" id="s7y-Nu-Y01">
                                             <rect key="frame" x="0.0" y="0.0" width="414" height="44"/>
@@ -332,7 +357,7 @@
                                         </tableViewCellContentView>
                                     </tableViewCell>
                                     <tableViewCell contentMode="scaleToFill" selectionStyle="none" hidesAccessoryWhenEditing="NO" indentationLevel="1" indentationWidth="0.0" reuseIdentifier="SettingsTableViewSwitchCell" textLabel="T7T-10-R9B" style="IBUITableViewCellStyleDefault" id="veW-Fm-2Hl" customClass="SettingsTableViewSwitchCell" customModule="Organic_Maps" customModuleProvider="target">
-                                        <rect key="frame" x="0.0" y="678" width="414" height="44"/>
+                                        <rect key="frame" x="0.0" y="766" width="414" height="44"/>
                                         <autoresizingMask key="autoresizingMask"/>
                                         <tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" tableViewCell="veW-Fm-2Hl" id="AP7-jd-F4b">
                                             <rect key="frame" x="0.0" y="0.0" width="414" height="44"/>
@@ -350,7 +375,7 @@
                                         </tableViewCellContentView>
                                     </tableViewCell>
                                     <tableViewCell contentMode="scaleToFill" selectionStyle="default" accessoryType="disclosureIndicator" hidesAccessoryWhenEditing="NO" indentationLevel="1" indentationWidth="0.0" reuseIdentifier="SettingsTableViewLinkCell" textLabel="DvL-U3-thq" detailTextLabel="aVn-3D-tVQ" style="IBUITableViewCellStyleValue1" id="nED-2n-gN6" customClass="SettingsTableViewLinkCell" customModule="Organic_Maps" customModuleProvider="target">
-                                        <rect key="frame" x="0.0" y="722" width="414" height="44"/>
+                                        <rect key="frame" x="0.0" y="810" width="414" height="44"/>
                                         <autoresizingMask key="autoresizingMask"/>
                                         <tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" tableViewCell="nED-2n-gN6" id="2oQ-0g-poj">
                                             <rect key="frame" x="0.0" y="0.0" width="383.5" height="44"/>
@@ -376,22 +401,22 @@
                                         </tableViewCellContentView>
                                     </tableViewCell>
                                     <tableViewCell contentMode="scaleToFill" selectionStyle="default" accessoryType="disclosureIndicator" hidesAccessoryWhenEditing="NO" indentationLevel="1" indentationWidth="0.0" reuseIdentifier="SettingsTableViewLinkCell" textLabel="nJu-c9-12J" detailTextLabel="2ux-Rf-ECf" style="IBUITableViewCellStyleValue1" id="KrE-Sc-fI1" customClass="SettingsTableViewLinkCell" customModule="Organic_Maps" customModuleProvider="target">
-                                        <rect key="frame" x="0.0" y="766" width="414" height="44"/>
+                                        <rect key="frame" x="0.0" y="854" width="414" height="44"/>
                                         <autoresizingMask key="autoresizingMask"/>
                                         <tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" tableViewCell="KrE-Sc-fI1" id="AKJ-VB-Pzr">
-                                            <rect key="frame" x="0.0" y="0.0" width="383.5" height="44"/>
+                                            <rect key="frame" x="0.0" y="0.0" width="395.5" height="44"/>
                                             <autoresizingMask key="autoresizingMask"/>
                                             <subviews>
-                                                <label opaque="NO" multipleTouchEnabled="YES" contentMode="left" insetsLayoutMarginsFromSafeArea="NO" text="Driving Options" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" id="nJu-c9-12J">
-                                                    <rect key="frame" x="20" y="15" width="88" height="14.5"/>
+                                                <label opaque="NO" multipleTouchEnabled="YES" contentMode="left" ambiguous="YES" insetsLayoutMarginsFromSafeArea="NO" text="Driving Options" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" id="nJu-c9-12J">
+                                                    <rect key="frame" x="8" y="15" width="88" height="14.5"/>
                                                     <autoresizingMask key="autoresizingMask"/>
                                                     <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                                                     <fontDescription key="fontDescription" type="system" pointSize="0.0"/>
                                                     <nil key="textColor"/>
                                                     <nil key="highlightedColor"/>
                                                 </label>
-                                                <label opaque="NO" multipleTouchEnabled="YES" contentMode="left" insetsLayoutMarginsFromSafeArea="NO" text="Detail" textAlignment="right" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" id="2ux-Rf-ECf">
-                                                    <rect key="frame" x="342.5" y="15" width="33" height="14.5"/>
+                                                <label opaque="NO" multipleTouchEnabled="YES" contentMode="left" ambiguous="YES" insetsLayoutMarginsFromSafeArea="NO" text="Detail" textAlignment="right" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" id="2ux-Rf-ECf">
+                                                    <rect key="frame" x="354.5" y="15" width="33" height="14.5"/>
                                                     <autoresizingMask key="autoresizingMask"/>
                                                     <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                                                     <fontDescription key="fontDescription" type="system" pointSize="0.0"/>
@@ -416,6 +441,7 @@
                         <outlet property="autoZoomCell" destination="veW-Fm-2Hl" id="zbI-m2-mDP"/>
                         <outlet property="compassCalibrationCell" destination="P5e-67-f4k" id="KcB-EC-S2y"/>
                         <outlet property="drivingOptionsCell" destination="KrE-Sc-fI1" id="XOl-eI-xJX"/>
+                        <outlet property="enableLoggingCell" destination="uxV-uf-u44" id="NcJ-C7-eff"/>
                         <outlet property="fontScaleCell" destination="pri-6G-9Zb" id="rHJ-ZT-lwM"/>
                         <outlet property="iCloudSynchronizationCell" destination="E6M-av-wQu" id="05q-Wq-SQa"/>
                         <outlet property="is3dCell" destination="0Lf-xU-P2U" id="obI-bL-FLh"/>

iphone/Maps/main.mm

@@ -1,10 +1,11 @@
 #import "MapsAppDelegate.h"
+#import "MWMSettings.h"
 
 #include "platform/platform.hpp"
-#include "platform/settings.hpp"
 
 int main(int argc, char * argv[])
 {
+  [MWMSettings initializeLogging];
   auto & p = GetPlatform();
   LOG(LINFO, ("Organic Maps", p.Version(), "started, detected CPU cores:", p.CpuCores()));