Upstream Chrome on iOS source code [8/11].

ios/chrome/browser/ui/settings/reauthentication_module.mm

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+#import "ios/chrome/browser/ui/settings/reauthentication_module.h"
+
+#import <LocalAuthentication/LocalAuthentication.h>
+
+#import "base/ios/weak_nsobject.h"
+#include "base/mac/scoped_nsobject.h"
+
+@implementation ReauthenticationModule {
+  // Authentication context on which the authentication policy is evaluated.
+  base::scoped_nsobject<LAContext> _context;
+
+  // Accessor allowing the module to request the update of the time when the
+  // successful re-authentication was performed and to get the time of the last
+  // successful re-authentication.
+  base::WeakNSProtocol<id<SuccessfulReauthTimeAccessor>>
+      _successfulReauthTimeAccessor;
+}
+
+- (instancetype)initWithSuccessfulReauthTimeAccessor:
+    (id<SuccessfulReauthTimeAccessor>)successfulReauthTimeAccessor {
+  DCHECK(successfulReauthTimeAccessor);
+  self = [super init];
+  if (self) {
+    _context.reset([[LAContext alloc] init]);
+    _successfulReauthTimeAccessor.reset(successfulReauthTimeAccessor);
+  }
+  return self;
+}
+
+- (BOOL)canAttemptReauth {
+  // The authentication method is Touch ID or passcode.
+  return
+      [_context canEvaluatePolicy:LAPolicyDeviceOwnerAuthentication error:nil];
+}
+
+- (void)attemptReauthWithLocalizedReason:(NSString*)localizedReason
+                                 handler:(void (^)(BOOL success))handler {
+  if ([self isPreviousAuthValid]) {
+    handler(YES);
+    return;
+  }
+
+  _context.reset([[LAContext alloc] init]);
+
+  // No fallback option is provided.
+  _context.get().localizedFallbackTitle = @"";
+
+  base::WeakNSObject<ReauthenticationModule> weakSelf(self);
+  void (^replyBlock)(BOOL, NSError*) = ^(BOOL success, NSError* error) {
+    dispatch_async(dispatch_get_main_queue(), ^{
+      base::scoped_nsobject<ReauthenticationModule> strongSelf(
+          [weakSelf retain]);
+      if (!strongSelf)
+        return;
+      if (success) {
+        [strongSelf.get()
+                ->_successfulReauthTimeAccessor updateSuccessfulReauthTime];
+      }
+      handler(success);
+    });
+  };
+
+  [_context evaluatePolicy:LAPolicyDeviceOwnerAuthentication
+           localizedReason:localizedReason
+                     reply:replyBlock];
+}
+
+- (BOOL)isPreviousAuthValid {
+  BOOL previousAuthValid = NO;
+  const int kIntervalForValidAuthInSeconds = 60;
+  NSDate* lastSuccessfulReauthTime =
+      [_successfulReauthTimeAccessor lastSuccessfulReauthTime];
+  if (lastSuccessfulReauthTime) {
+    NSDate* currentTime = [NSDate date];
+    NSTimeInterval timeSincePreviousSuccessfulAuth =
+        [currentTime timeIntervalSinceDate:lastSuccessfulReauthTime];
+    if (timeSincePreviousSuccessfulAuth < kIntervalForValidAuthInSeconds) {
+      previousAuthValid = YES;
+    }
+  }
+  return previousAuthValid;
+}
+
+@end