Ability to revert all changes or changes for key

Author: kashif

Parse/PFObject.h

@@ -141,7 +141,7 @@ NS_REQUIRES_PROPERTY_DEFINITIONS
 /*!
  @abstract Sets the object associated with a given key.
 
- @param object The object for `key`. A strong reference to the object is maintaned by PFObject.
+ @param object The object for `key`. A strong reference to the object is maintained by PFObject.
  Raises an `NSInvalidArgumentException` if `object` is `nil`.
  If you need to represent a `nil` value - use `NSNull`.
  @param key The key for `object`.
@@ -176,7 +176,7 @@ NS_REQUIRES_PROPERTY_DEFINITIONS
  @discussion This method enables usage of literal syntax on `PFObject`.
  E.g. `object[@"key"] = @"value";`
 
- @param object The object for `key`. A strong reference to the object is maintaned by PFObject.
+ @param object The object for `key`. A strong reference to the object is maintained by PFObject.
  Raises an `NSInvalidArgumentException` if `object` is `nil`.
  If you need to represent a `nil` value - use `NSNull`.
  @param key The key for `object`.
@@ -202,6 +202,19 @@ NS_REQUIRES_PROPERTY_DEFINITIONS
  */
 - (PFRelation *)relationforKey:(NSString *)key PARSE_DEPRECATED("Please use -relationForKey: instead.");
 
+/*!
+ @abstract Clears any changes to this object made since the last call to save and sets it back to the server state.
+ */
+- (void)revert;
+
+/*!
+ @abstract Clears any changes to this object's key that were done after last successful save and sets it back to the
+ server state.
+ 
+ @param key The key to revert changes for.
+ */
+- (void)revertObjectForKey:(NSString *)key;
+
 ///--------------------------------------
 /// @name Array Accessors
 ///--------------------------------------

Parse/PFObject.m

@@ -2313,6 +2313,40 @@ - (void)removeObjectForKey:(NSString *)key {
     }
 }
 
+- (void)revert {
+    @synchronized (lock) {
+        if ([self isDirty]) {
+            NSMutableArray *removedKeys = [NSMutableArray array];
+            [removedKeys addObjectsFromArray: [self allKeys]];
+            for (PFOperationSet *operationSet in operationSetQueue) {
+                for (NSString *key in operationSet.keyEnumerator) {
+                    [removedKeys addObject:key];
+                }
+            }
+            
+            PFOperationSet *changes = [self unsavedChanges];
+            for (NSString *key in changes.keyEnumerator) {
+                [changes removeObjectForKey:key];
+            }
+            
+            [self rebuildEstimatedData];
+            [_availableKeys minusSet:[NSSet setWithArray:removedKeys]];
+            [self checkpointAllMutableContainers];
+        }
+    }
+}
+
+- (void)revertObjectForKey:(NSString *)key {
+    @synchronized (lock) {
+        if ([self isDirtyForKey:key]) {
+            [[self unsavedChanges] removeObjectForKey:key];
+            [self rebuildEstimatedData];
+            [_availableKeys removeObject:key];
+            [self checkpointAllMutableContainers];
+        }
+    }
+}
+
 #pragma mark Relations
 
 - (PFRelation *)relationforKey:(NSString *)key {

Tests/Unit/ObjectUnitTests.m

@@ -10,6 +10,7 @@
 #import "PFObject.h"
 #import "PFUnitTestCase.h"
 #import "Parse_Private.h"
+#import "PFObjectPrivate.h"
 
 @interface ObjectUnitTests : PFUnitTestCase
 
@@ -182,4 +183,27 @@ - (void)testKeyValueCoding {
     XCTAssertEqualObjects([object valueForKey:@"yarr"], @"yolo");
 }
 
+- (void)testRevert {
+    NSDate *date = [NSDate date];
+    NSNumber *number = @0.75;
+    PFObject *object = [PFObject _objectFromDictionary:@{ @"yarr" : date, @"score": number } defaultClassName:@"Test" completeData:YES];
+    object[@"yarr"] = @"yolo";
+    [object revert];
+    XCTAssertEqualObjects(object[@"yarr"], date);
+    XCTAssertEqualObjects(object[@"score"], number);
+}
+
+- (void)testRevertObjectForKey {
+    NSDate *date = [NSDate date];
+    NSNumber *number = @0.75;
+    PFObject *object = [PFObject _objectFromDictionary:@{ @"yarr" : date,
+                                                          @"score" : @1.0 }
+                                      defaultClassName:@"Test" completeData:YES];
+    object[@"yarr"] = @"yolo";
+    object[@"score"] = number;
+    [object revertObjectForKey:@"yarr"];
+    XCTAssertEqualObjects(object[@"yarr"], date);
+    XCTAssertEqualObjects(object[@"score"], number);
+}
+
 @end