Merge pull request #31 from venmo/daz/fix_freeze

Prevent LAContext evaluatePolicy:localizedReason:reply: from being invoked multiple times
venmo · Jan 13, 2015 · 520d182 · 520d182
2 parents e9aa74d + f27ca66
commit 520d182
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Showing 2 changed files with 27 additions and 16 deletions.
diff --git a/VENTouchLock/VENTouchLock.h b/VENTouchLock/VENTouchLock.h
@@ -9,6 +9,7 @@ typedef NS_ENUM(NSUInteger, VENTouchLockTouchIDResponse) {
     VENTouchLockTouchIDResponseSuccess,
     VENTouchLockTouchIDResponseUsePasscode,
     VENTouchLockTouchIDResponseCanceled,
+    VENTouchLockTouchIDResponsePromptAlreadyPresent,
 };
 
 @interface VENTouchLock : NSObject

diff --git a/VENTouchLock/VENTouchLock.m b/VENTouchLock/VENTouchLock.m
@@ -127,20 +127,23 @@ - (void)requestTouchIDWithCompletion:(void (^)(VENTouchLockTouchIDResponse))comp
 
 - (void)requestTouchIDWithCompletion:(void (^)(VENTouchLockTouchIDResponse))completionBlock reason:(NSString *)reason
 {
+    static BOOL isTouchIDPresented = NO;
     if ([[self class] canUseTouchID]) {
-        LAContext *context = [[LAContext alloc] init];
-        context.localizedFallbackTitle = NSLocalizedString(@"Enter Passcode", nil);
-        [context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics
-                localizedReason:reason
-                          reply:^(BOOL success, NSError *error) {
-                              dispatch_async(dispatch_get_main_queue(), ^{
-                                  if (success) {
-                                      if (completionBlock) {
-                                          completionBlock(VENTouchLockTouchIDResponseSuccess);
+        if (!isTouchIDPresented) {
+            isTouchIDPresented = YES;
+            LAContext *context = [[LAContext alloc] init];
+            context.localizedFallbackTitle = NSLocalizedString(@"Enter Passcode", nil);
+            [context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics
+                    localizedReason:reason
+                              reply:^(BOOL success, NSError *error) {
+                                  isTouchIDPresented = NO;
+                                  dispatch_async(dispatch_get_main_queue(), ^{
+                                      if (success) {
+                                          if (completionBlock) {
+                                              completionBlock(VENTouchLockTouchIDResponseSuccess);
+                                          }
                                       }
-                                  }
-                                  else {
-                                      if (completionBlock) {
+                                      else {
                                           VENTouchLockTouchIDResponse response;
                                           switch (error.code) {
                                               case LAErrorUserFallback:
@@ -153,11 +156,18 @@ - (void)requestTouchIDWithCompletion:(void (^)(VENTouchLockTouchIDResponse))comp
                                                   response = VENTouchLockTouchIDResponseUndefined;
                                                   break;
                                           }
-                                          completionBlock(response);
+                                          if (completionBlock) {
+                                              completionBlock(response);
+                                          }
                                       }
-                                  }
-                              });
-                          }];
+                                  });
+                              }];
+        }
+        else {
+            if (completionBlock) {
+                completionBlock(VENTouchLockTouchIDResponsePromptAlreadyPresent);
+            }
+        }
     }
 }