Fix bug related to data protection mode "complete until first auth" where FIC would incorrectly think that data was inaccessible while locked, even though the device had previously been unlocked.

Author: Mallory Paine

FastImageCache/FICImageTable.m

@@ -63,7 +63,8 @@ @interface FICImageTable () {
     NSCountedSet *_inUseEntries;
     NSDictionary *_imageFormatDictionary;
 
-    BOOL _isFileDataProtected;
+    NSString *_fileDataProtectionMode;
+    BOOL _canAccessData;
 }
 @property(nonatomic, weak) FICImageCache *imageCache;
 @end
@@ -172,10 +173,7 @@ - (instancetype)initWithFormat:(FICImageFormat *)imageFormat imageCache:(FICImag
         }
 
         NSDictionary *attributes = [fileManager attributesOfItemAtPath:_filePath error:NULL];
-        NSString *protectionMode = [attributes objectForKey:NSFileProtectionKey];
-        if (protectionMode) {
-            _isFileDataProtected = [protectionMode isEqualToString:NSFileProtectionNone] == NO;
-        }
+        _fileDataProtectionMode = [attributes objectForKey:NSFileProtectionKey];
 
         _fileDescriptor = open([_filePath fileSystemRepresentation], O_RDWR | O_CREAT, 0666);
 
@@ -496,8 +494,20 @@ - (void)_setEntryCount:(NSInteger)entryCount {
 // by using NSFileProtectionNone
 - (BOOL)canAccessEntryData {
     BOOL result = YES;
-    if (_isFileDataProtected) {
+    if ([_fileDataProtectionMode isEqualToString:NSFileProtectionComplete]) {
         result = [[UIApplication sharedApplication] isProtectedDataAvailable];
+    } else if ([_fileDataProtectionMode isEqualToString:NSFileProtectionCompleteUntilFirstUserAuthentication]) {
+        // For "complete until first auth", if we were previously able to access data, then we'll still be able to
+        // access it. If we haven't yet been able to access data, we'll need to try until we are successful.
+        if (_canAccessData == NO) {
+            if ([[UIApplication sharedApplication] isProtectedDataAvailable]) {
+                // we are unlocked, so we're good to go.
+                _canAccessData = YES;
+            } else {
+                // we are locked, so try to access data.
+                _canAccessData = [NSData dataWithContentsOfMappedFile:_filePath] != nil;
+            }
+        }
     }
     return result;
 }