Add function to gul secure encoding to encode multiple calsses (#4282)

* style

* secure coding

Author: VinayGuthal

GoogleUtilities/Example/Tests/SecureCoding/GULSecureCodingTests.m

@@ -36,7 +36,7 @@ @interface GULSecureCodingTests : XCTestCase
 
 @implementation GULSecureCodingTests
 
-- (void)testArchiveUnarchive {
+- (void)testArchiveUnarchiveSingleClass {
   NSDictionary *objectToArchive = @{@"key1" : @"value1", @"key2" : @(2)};
 
   NSError *error;
@@ -51,6 +51,22 @@ - (void)testArchiveUnarchive {
   XCTAssert([objectToArchive isEqualToDictionary:unarchivedObject]);
 }
 
+- (void)testArchiveUnarchiveMultipleClasses {
+  NSDictionary *objectToArchive = @{@"key1" : [NSDate date], @"key2" : @(2)};
+
+  NSError *error;
+  NSData *archiveData = [GULSecureCoding archivedDataWithRootObject:objectToArchive error:&error];
+  XCTAssertNil(error);
+  XCTAssertNotNil(archiveData);
+
+  NSDictionary *unarchivedObject = [GULSecureCoding
+      unarchivedObjectOfClasses:[NSSet setWithArray:@[ NSDictionary.class, NSDate.class ]]
+                       fromData:archiveData
+                          error:&error];
+  XCTAssertNil(error);
+  XCTAssert([objectToArchive isEqualToDictionary:unarchivedObject]);
+}
+
 - (void)testArchivingIncompatibleObjectError {
   SecureCodingIncompatibleObject *objectToArchive = [[SecureCodingIncompatibleObject alloc] init];
 

GoogleUtilities/SecureCoding/GULSecureCoding.m

@@ -18,21 +18,21 @@
 
 @implementation GULSecureCoding
 
-+ (nullable id)unarchivedObjectOfClass:(Class)class
-                              fromData:(NSData *)data
-                                 error:(NSError **)outError {
++ (nullable id)unarchivedObjectOfClasses:(NSSet<Class> *)classes
+                                fromData:(NSData *)data
+                                   error:(NSError **)outError {
   id object;
 #if __has_builtin(__builtin_available)
   if (@available(macOS 10.13, iOS 11.0, tvOS 11.0, *)) {
-    object = [NSKeyedUnarchiver unarchivedObjectOfClass:class fromData:data error:outError];
+    object = [NSKeyedUnarchiver unarchivedObjectOfClasses:classes fromData:data error:outError];
   } else
 #endif  // __has_builtin(__builtin_available)
   {
     @try {
       NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
       unarchiver.requiresSecureCoding = YES;
 
-      object = [unarchiver decodeObjectOfClass:class forKey:NSKeyedArchiveRootObjectKey];
+      object = [unarchiver decodeObjectOfClasses:classes forKey:NSKeyedArchiveRootObjectKey];
     } @catch (NSException *exception) {
       if (outError) {
         *outError = [self archivingErrorWithException:exception];
@@ -50,6 +50,12 @@ + (nullable id)unarchivedObjectOfClass:(Class)class
   return object;
 }
 
++ (nullable id)unarchivedObjectOfClass:(Class)class
+                              fromData:(NSData *)data
+                                 error:(NSError **)outError {
+  return [self unarchivedObjectOfClasses:[NSSet setWithObject:class] fromData:data error:outError];
+}
+
 + (nullable NSData *)archivedDataWithRootObject:(id<NSCoding>)object error:(NSError **)outError {
   NSData *archiveData;
 #if __has_builtin(__builtin_available)

GoogleUtilities/SecureCoding/Public/GULSecureCoding.h

@@ -21,6 +21,10 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @interface GULSecureCoding : NSObject
 
++ (nullable id)unarchivedObjectOfClasses:(NSSet<Class> *)classes
+                                fromData:(NSData *)data
+                                   error:(NSError **)outError;
+
 + (nullable id)unarchivedObjectOfClass:(Class)class
                               fromData:(NSData *)data
                                  error:(NSError **)outError;