[ios, macos] Offline storage size API

Added a property to MGLOfflineStorage that indicates the disk space occupied by all cached and offline resources.

Fixes #5580.

platform/darwin/src/MGLOfflineStorage.h

@@ -217,6 +217,14 @@ typedef void (^MGLOfflinePackRemovalCompletionHandler)(NSError * _Nullable error
  */
 - (void)setMaximumAllowedMapboxTiles:(uint64_t)maximumCount;
 
+/**
+ The cumulative size, measured in bytes, of all downloaded resources on disk.
+ 
+ The returned value includes all resources, including tiles, whether downloaded
+ as part of an offline pack or due to caching during normal use of `MGLMapView`.
+ */
+@property (nonatomic, readonly) unsigned long long countOfBytesCompleted;
+
 @end
 
 NS_ASSUME_NONNULL_END

platform/darwin/src/MGLOfflineStorage.mm

@@ -275,6 +275,19 @@ NSString * const MGLOfflinePackMaximumCountUserInfoKey = @"MaximumCount";
     _mbglFileSource->setOfflineMapboxTileCountLimit(maximumCount);
 }
 
+#pragma mark -
+
+- (unsigned long long)countOfBytesCompleted {
+    NSURL *cacheURL = [[self class] cacheURLIncludingSubdirectory:YES];
+    NSString *cachePath = cacheURL.path;
+    if (!cachePath) {
+        return 0;
+    }
+    
+    NSDictionary *attributes = [[NSFileManager defaultManager] attributesOfItemAtPath:cachePath error:NULL];
+    return attributes.fileSize;
+}
+
 #pragma mark MGLOfflinePackDelegate methods
 
 - (void)offlinePack:(MGLOfflinePack *)pack progressDidChange:(__unused MGLOfflinePackProgress)progress {

platform/darwin/test/MGLOfflineStorageTests.m

@@ -144,4 +144,8 @@
     XCTAssertEqual([MGLOfflineStorage sharedOfflineStorage].packs.count, countOfPacks - 1, @"Removed pack should have been removed from the canonical collection of packs owned by the shared offline storage object. This assertion can fail if this test is run before -testAAALoadPacks or -testAddPack.");
 }
 
+- (void)testCountOfBytesCompleted {
+    XCTAssertGreaterThan([MGLOfflineStorage sharedOfflineStorage].countOfBytesCompleted, 0);
+}
+
 @end

platform/ios/CHANGELOG.md

@@ -8,6 +8,7 @@ Mapbox welcomes participation and contributions from everyone.  Please read [CON
 * As the user zooms in, tiles from lower zoom levels are scaled up until tiles for higher zoom levels are loaded. ([#5143](https://github.com/mapbox/mapbox-gl-native/pull/5143))
 * Added [quadkey](https://msdn.microsoft.com/en-us/library/bb259689.aspx) support and limited WMS support in raster tile URL templates. ([#5628](https://github.com/mapbox/mapbox-gl-native/pull/5628))
 * Fixed an issue causing polyline and polygon annotations to disappear when the zoom level is one less than the maximum zoom level. ([#5418](https://github.com/mapbox/mapbox-gl-native/pull/5418))
+* Added a property to MGLOfflineStorage, `countOfBytesCompleted`, that indicates the disk space occupied by all cached and offline resources. ([#5585](https://github.com/mapbox/mapbox-gl-native/pull/5585))
 * The `text-pitch-alignment` property is now supported in stylesheets for improved street label legibility on a tilted map. ([#5288](https://github.com/mapbox/mapbox-gl-native/pull/5288))
 * The `icon-text-fit` and `icon-text-fit-padding` properties are now supported in stylesheets, allowing the background of a shield to automatically resize to fit the shield’s text. ([#5334](https://github.com/mapbox/mapbox-gl-native/pull/5334))
 * Improved the performance of relocating a non-view-backed point annotation by changing its `coordinate` property. ([#5385](https://github.com/mapbox/mapbox-gl-native/pull/5385))

platform/macos/CHANGELOG.md

@@ -8,6 +8,7 @@
 * As the user zooms in, tiles from lower zoom levels are scaled up until tiles for higher zoom levels are loaded. ([#5143](https://github.com/mapbox/mapbox-gl-native/pull/5143))
 * Added [quadkey](https://msdn.microsoft.com/en-us/library/bb259689.aspx) support and limited WMS support in raster tile URL templates. ([#5628](https://github.com/mapbox/mapbox-gl-native/pull/5628))
 * Fixed an issue causing polyline and polygon annotations to disappear when the zoom level is one less than the maximum zoom level. ([#5418](https://github.com/mapbox/mapbox-gl-native/pull/5418))
+* Added a property to MGLOfflineStorage, `countOfBytesCompleted`, that indicates the disk space occupied by all cached and offline resources. ([#5585](https://github.com/mapbox/mapbox-gl-native/pull/5585))
 * The `text-pitch-alignment` property is now supported in stylesheets for improved street label legibility on a tilted map. ([#5288](https://github.com/mapbox/mapbox-gl-native/pull/5288))
 * The `icon-text-fit` and `icon-text-fit-padding` properties are now supported in stylesheets, allowing the background of a shield to automatically resize to fit the shield’s text. ([#5334](https://github.com/mapbox/mapbox-gl-native/pull/5334))
 * Improved the performance of relocating a point annotation by changing its `coordinate` property. ([#5385](https://github.com/mapbox/mapbox-gl-native/pull/5385))