Fix all IID analyzer warnings (#2613)

Author: charlotteliang

Firebase/InstanceID/FIRInstanceIDAuthKeyChain.m

@@ -33,7 +33,7 @@ @interface FIRInstanceIDAuthKeychain ()
 // cachedKeychainData is keyed by service and account, the value is an array of NSData.
 // It is used to cache the tokens per service, per account, as well as checkin data per service,
 // per account inside the keychain.
-@property(nonatomic, copy)
+@property(nonatomic)
     NSMutableDictionary<NSString *, NSMutableDictionary<NSString *, NSArray<NSData *> *> *>
         *cachedKeychainData;
 
@@ -89,7 +89,8 @@ - (NSMutableDictionary *)keychainQueryForService:(NSString *)service account:(NS
   keychainQuery[(__bridge id)kSecReturnAttributes] = (__bridge id)kCFBooleanTrue;
   keychainQuery[(__bridge id)kSecMatchLimit] = (__bridge id)kSecMatchLimitAll;
   // FIRInstanceIDKeychain should only take a query and return a result, will handle the query here.
-  CFArrayRef passwordInfos = [[FIRInstanceIDKeychain sharedInstance] itemWithQuery:keychainQuery];
+  NSArray *passwordInfos =
+      CFBridgingRelease([[FIRInstanceIDKeychain sharedInstance] itemWithQuery:keychainQuery]);
 
   if (!passwordInfos) {
     // Nothing was found, simply return from this sync block.
@@ -105,19 +106,14 @@ - (NSMutableDictionary *)keychainQueryForService:(NSString *)service account:(NS
     }
     return @[];
   }
-  NSInteger numPasswords = CFArrayGetCount(passwordInfos);
+  NSInteger numPasswords = passwordInfos.count;
   results = [[NSMutableArray alloc] init];
-  if (0 < numPasswords) {
-    for (NSUInteger i = 0; i < numPasswords; i++) {
-      NSDictionary *passwordInfo = [((__bridge NSArray *)passwordInfos) objectAtIndex:i];
-      if (passwordInfo[(__bridge id)kSecValueData]) {
-        [results addObject:passwordInfo[(__bridge id)kSecValueData]];
-      }
+  for (NSUInteger i = 0; i < numPasswords; i++) {
+    NSDictionary *passwordInfo = [passwordInfos objectAtIndex:i];
+    if (passwordInfo[(__bridge id)kSecValueData]) {
+      [results addObject:passwordInfo[(__bridge id)kSecValueData]];
     }
   }
-  if (passwordInfos != NULL) {
-    CFRelease(passwordInfos);
-  }
 
   // We query the keychain because it didn't exist in cache, now query is done, update the result in
   // the cache.

Firebase/InstanceID/FIRInstanceIDKeyPairStore.m

@@ -60,7 +60,7 @@
 // Query the key given a tag
 SecKeyRef FIRInstanceIDCachedKeyRefWithTag(NSString *tag) {
   _FIRInstanceIDDevAssert([tag length], @"Invalid tag for keychain specified");
-  if (![tag length]) {
+  if (!tag.length) {
     return NULL;
   }
   NSDictionary *queryKey = FIRInstanceIDKeyPairQuery(tag, YES, NO);
@@ -279,7 +279,9 @@ - (FIRInstanceIDKeyPair *)validCachedKeyPairWithSubtype:(NSString *)subtype
     // There is no need to reset keypair again here as FIRInstanceID init call is always
     // going to be ahead of this call, which already trigger keypair reset if it's new install
     FIRInstanceIDErrorCode code = kFIRInstanceIDErrorCodeInvalidKeyPairCreationTime;
-    *error = [NSError errorWithFIRInstanceIDErrorCode:code];
+    if (error) {
+      *error = [NSError errorWithFIRInstanceIDErrorCode:code];
+    }
     return nil;
   }
 }

Firebase/InstanceID/FIRInstanceIDStore.h

@@ -96,8 +96,8 @@ NS_ASSUME_NONNULL_BEGIN
  *  @return The cached token info if any for the given authorizedEntity and scope else
  *          returns nil.
  */
-- (FIRInstanceIDTokenInfo *)tokenInfoWithAuthorizedEntity:(NSString *)authorizedEntity
-                                                    scope:(NSString *)scope;
+- (nullable FIRInstanceIDTokenInfo *)tokenInfoWithAuthorizedEntity:(NSString *)authorizedEntity
+                                                             scope:(NSString *)scope;
 /**
  *  Return all cached token infos from the Keychain.
  *

Firebase/InstanceID/FIRInstanceIDTokenDeleteOperation.h

@@ -21,7 +21,7 @@ NS_ASSUME_NONNULL_BEGIN
 @interface FIRInstanceIDTokenDeleteOperation : FIRInstanceIDTokenOperation
 
 - (instancetype)initWithAuthorizedEntity:(nullable NSString *)authorizedEntity
-                                   scope:(NSString *)scope
+                                   scope:(nullable NSString *)scope
                       checkinPreferences:(FIRInstanceIDCheckinPreferences *)checkinPreferences
                                  keyPair:(nullable FIRInstanceIDKeyPair *)keyPair
                                   action:(FIRInstanceIDTokenAction)action;

Firebase/InstanceID/FIRInstanceIDTokenOperation.h

@@ -57,7 +57,7 @@ typedef void (^FIRInstanceIDTokenOperationCompletion)(FIRInstanceIDTokenOperatio
 
 @property(nonatomic, readonly) FIRInstanceIDTokenAction action;
 @property(nonatomic, readonly, nullable) NSString *authorizedEntity;
-@property(nonatomic, readonly) NSString *scope;
+@property(nonatomic, readonly, nullable) NSString *scope;
 @property(nonatomic, readonly, nullable) NSDictionary<NSString *, NSString *> *options;
 @property(nonatomic, readonly, strong) FIRInstanceIDCheckinPreferences *checkinPreferences;
 @property(nonatomic, readonly, strong) FIRInstanceIDKeyPair *keyPair;