7 files changed, 100 insertions, 7 deletions
diff --git a/.jazzy.yaml b/.jazzy.yaml
index 853db0a4f7..602e8cdb0d 100644
--- a/.jazzy.yaml
+++ b/.jazzy.yaml
@@ -49,9 +49,12 @@ custom_categories:
       - MGLOfflinePackMaximumMapboxTilesReachedNotification
       - MGLOfflinePackProgress
       - MGLOfflinePackProgressChangedNotification
+      - MGLOfflinePackProgressUserInfoKey
       - MGLOfflinePackRemovalCompletionHandler
       - MGLOfflinePackState
+      - MGLOfflinePackStateUserInfoKey
       - MGLTilePyramidOfflineRegion
+      - NSValue(MGLOfflinePackAdditions)
   - name: Geometry
     children:
       - MGLCoordinateBounds
diff --git a/platform/darwin/include/MGLOfflinePack.h b/platform/darwin/include/MGLOfflinePack.h
index 185bba038c..b65fed3849 100644
--- a/platform/darwin/include/MGLOfflinePack.h
+++ b/platform/darwin/include/MGLOfflinePack.h
@@ -161,4 +161,25 @@ typedef struct MGLOfflinePackProgress {
 
 @end
 
+/**
+ Methods for round-tripping `MGLOfflinePackProgress` values.
+ */
+@interface NSValue (MGLOfflinePackAdditions)
+
+/**
+ Creates a new value object containing the given `MGLOfflinePackProgress`
+ structure.
+ 
+ @param progress The value for the new object.
+ @return A new value object that contains the offline pack progress information.
+ */
++ (NSValue *)valueWithMGLOfflinePackProgress:(MGLOfflinePackProgress)progress;
+
+/**
+ The `MGLOfflinePackProgress` structure representation of the value.
+ */
+@property (readonly) MGLOfflinePackProgress MGLOfflinePackProgressValue;
+
+@end
+
 NS_ASSUME_NONNULL_END
diff --git a/platform/darwin/include/MGLOfflineStorage.h b/platform/darwin/include/MGLOfflineStorage.h
index f9ddba0382..5544663d3e 100644
--- a/platform/darwin/include/MGLOfflineStorage.h
+++ b/platform/darwin/include/MGLOfflineStorage.h
@@ -14,8 +14,11 @@ NS_ASSUME_NONNULL_BEGIN
  resources are required for offline viewing. This notification is posted
  whenever any field in the `progress` property changes.
  
- The `object` is the `MGLOfflinePack` object whose progress changed. For details
- about the pack’s current progress, use the pack’s `progress` property.
+ The `object` is the `MGLOfflinePack` object whose progress changed. The
+ `userInfo` dictionary contains the pack’s current state in the
+ `MGLOfflinePackStateUserInfoKey` key and details about the pack’s current
+ progress in the `MGLOfflinePackProgressUserInfoKey` key. You may also consult
+ the pack’s `state` and `progress` properties, which provide the same values.
  
  If you only need to observe changes in a particular pack’s progress, you can
  alternatively observe KVO change notifications to the pack’s `progress` key
@@ -52,17 +55,37 @@ extern NSString * const MGLOfflinePackErrorNotification;
 extern NSString * const MGLOfflinePackMaximumMapboxTilesReachedNotification;
 
 /**
+ The key for an `NSNumber` object that indicates an offline pack’s current
+ state. This key is used in the `userInfo` dictionary of an
+ `MGLOfflinePackProgressChangedNotification` notification. Call `-integerValue`
+ on the object to receive the `MGLOfflinePackState`-typed state.
+ */
+extern NSString * const MGLOfflinePackStateUserInfoKey;
+
+/**
+ The key for an `NSValue` object that indicates an offline pack’s current
+ progress. This key is used in the `userInfo` dictionary of an
+ `MGLOfflinePackProgressChangedNotification` notification. Call
+ `-MGLOfflinePackProgressValue` on the object to receive the
+ `MGLOfflinePackProgress`-typed progress.
+ */
+extern NSString * const MGLOfflinePackProgressUserInfoKey;
+
+/**
  The key for an `NSError` object that is encountered in the course of
- downloading an offline pack. The error’s domain is `MGLErrorDomain`. See
- `MGLErrorCode` for possible error codes.
+ downloading an offline pack. This key is used in the `userInfo` dictionary of
+ an `MGLOfflinePackErrorNotification` notification. The error’s domain is
+ `MGLErrorDomain`. See `MGLErrorCode` for possible error codes.
  */
 extern NSString * const MGLOfflinePackErrorUserInfoKey;
 
 /**
  The key for an `NSNumber` object that indicates the maximum number of
  Mapbox-hosted tiles that may be downloaded and stored on the current device.
- Call `-unsignedLongLongValue` on the object to receive the `uint64_t`-typed
- tile limit.
+ This key is used in the `userInfo` dictionary of an
+ `MGLOfflinePackMaximumMapboxTilesReachedNotification` notification. Call
+ `-unsignedLongLongValue` on the object to receive the `uint64_t`-typed tile
+ limit.
  */
 extern NSString * const MGLOfflinePackMaximumCountUserInfoKey;
 
diff --git a/platform/darwin/src/MGLOfflinePack.mm b/platform/darwin/src/MGLOfflinePack.mm
index 30b268aaf1..05ff35ec7f 100644
--- a/platform/darwin/src/MGLOfflinePack.mm
+++ b/platform/darwin/src/MGLOfflinePack.mm
@@ -204,3 +204,17 @@ void MBGLOfflineRegionObserver::mapboxTileCountLimitExceeded(uint64_t limit) {
         [pack.delegate offlinePack:pack didReceiveMaximumAllowedMapboxTiles:limit];
     });
 }
+
+@implementation NSValue (MGLOfflinePackAdditions)
+
++ (NSValue *)valueWithMGLOfflinePackProgress:(MGLOfflinePackProgress)progress {
+    return [NSValue value:&progress withObjCType:@encode(MGLOfflinePackProgress)];
+}
+
+- (MGLOfflinePackProgress)MGLOfflinePackProgressValue {
+    MGLOfflinePackProgress progress;
+    [self getValue:&progress];
+    return progress;
+}
+
+@end
diff --git a/platform/darwin/src/MGLOfflineStorage.mm b/platform/darwin/src/MGLOfflineStorage.mm
index 619e4ce1ab..3d171ca203 100644
--- a/platform/darwin/src/MGLOfflineStorage.mm
+++ b/platform/darwin/src/MGLOfflineStorage.mm
@@ -15,6 +15,8 @@ NSString * const MGLOfflinePackProgressChangedNotification = @"MGLOfflinePackPro
 NSString * const MGLOfflinePackErrorNotification = @"MGLOfflinePackError";
 NSString * const MGLOfflinePackMaximumMapboxTilesReachedNotification = @"MGLOfflinePackMaximumMapboxTilesReached";
 
+NSString * const MGLOfflinePackStateUserInfoKey = @"State";
+NSString * const MGLOfflinePackProgressUserInfoKey = @"Progress";
 NSString * const MGLOfflinePackErrorUserInfoKey = @"Error";
 NSString * const MGLOfflinePackMaximumCountUserInfoKey = @"MaximumCount";
 
@@ -242,7 +244,10 @@ NSString * const MGLOfflinePackMaximumCountUserInfoKey = @"MaximumCount";
 #pragma mark MGLOfflinePackDelegate methods
 
 - (void)offlinePack:(MGLOfflinePack *)pack progressDidChange:(__unused MGLOfflinePackProgress)progress {
-    [[NSNotificationCenter defaultCenter] postNotificationName:MGLOfflinePackProgressChangedNotification object:pack];
+    [[NSNotificationCenter defaultCenter] postNotificationName:MGLOfflinePackProgressChangedNotification object:pack userInfo:@{
+        MGLOfflinePackStateUserInfoKey: @(pack.state),
+        MGLOfflinePackProgressUserInfoKey: [NSValue valueWithMGLOfflinePackProgress:progress],
+    }];
 }
 
 - (void)offlinePack:(MGLOfflinePack *)pack didReceiveError:(NSError *)error {
diff --git a/platform/osx/test/MGLOfflinePackTests.m b/platform/osx/test/MGLOfflinePackTests.m
index c33a72cc08..41262d16c7 100644
--- a/platform/osx/test/MGLOfflinePackTests.m
+++ b/platform/osx/test/MGLOfflinePackTests.m
@@ -22,4 +22,19 @@
     XCTAssertThrowsSpecificNamed([invalidPack suspend], NSException, @"Invalid offline pack", @"Invalid offline pack should raise an exception when being suspended.");
 }
 
+- (void)testProgressBoxing {
+    MGLOfflinePackProgress progress = {
+        .countOfResourcesCompleted = 1,
+        .countOfResourcesExpected = 2,
+        .countOfBytesCompleted = 7,
+        .maximumResourcesExpected = UINT64_MAX,
+    };
+    MGLOfflinePackProgress roundTrippedProgress = [NSValue valueWithMGLOfflinePackProgress:progress].MGLOfflinePackProgressValue;
+    
+    XCTAssertEqual(progress.countOfResourcesCompleted, roundTrippedProgress.countOfResourcesCompleted, @"Completed resources should round-trip.");
+    XCTAssertEqual(progress.countOfResourcesExpected, roundTrippedProgress.countOfResourcesExpected, @"Expected resources should round-trip.");
+    XCTAssertEqual(progress.countOfBytesCompleted, roundTrippedProgress.countOfBytesCompleted, @"Completed bytes should round-trip.");
+    XCTAssertEqual(progress.maximumResourcesExpected, roundTrippedProgress.maximumResourcesExpected, @"Maximum expected resources should round-trip.");
+}
+
 @end
diff --git a/platform/osx/test/MGLOfflineStorageTests.m b/platform/osx/test/MGLOfflineStorageTests.m
index ff738f9239..3657f93d48 100644
--- a/platform/osx/test/MGLOfflineStorageTests.m
+++ b/platform/osx/test/MGLOfflineStorageTests.m
@@ -82,6 +82,18 @@
     [self expectationForNotification:MGLOfflinePackProgressChangedNotification object:pack handler:^BOOL(NSNotification * _Nonnull notification) {
         MGLOfflinePack *notificationPack = notification.object;
         XCTAssert([notificationPack isKindOfClass:[MGLOfflinePack class]], @"Object of notification should be an MGLOfflinePack.");
+        
+        NSDictionary *userInfo = notification.userInfo;
+        XCTAssertNotNil(userInfo, @"Progress change notification should have a userInfo dictionary.");
+        
+        NSNumber *stateNumber = userInfo[MGLOfflinePackStateUserInfoKey];
+        XCTAssert([stateNumber isKindOfClass:[NSNumber class]], @"Progress change notification’s state should be an NSNumber.");
+        XCTAssertEqual(stateNumber.integerValue, pack.state, @"State in a progress change notification should match the pack’s state.");
+        
+        NSValue *progressValue = userInfo[MGLOfflinePackProgressUserInfoKey];
+        XCTAssert([progressValue isKindOfClass:[NSValue class]], @"Progress change notification’s progress should be an NSValue.");
+        XCTAssertEqualObjects(progressValue, [NSValue valueWithMGLOfflinePackProgress:pack.progress], @"Progress change notification’s progress should match pack’s progress.");
+        
         return notificationPack == pack && pack.state == MGLOfflinePackStateInactive;
     }];
     [self waitForExpectationsWithTimeout:1 handler:nil];