[ios, macos] Ignore progress updates after suspending

-suspend and -resume are now presumed to be synchronous, even if technically they remain asynchronous under the hood.

2 files changed, 21 insertions, 11 deletions

diff --git a/platform/darwin/src/MGLOfflinePack.h b/platform/darwin/src/MGLOfflinePack.h
index 3d4422da33..a14d001d0f 100644
--- a/platform/darwin/src/MGLOfflinePack.h
+++ b/platform/darwin/src/MGLOfflinePack.h
@@ -144,11 +144,6 @@ typedef struct MGLOfflinePackProgress {
 /**
  Resumes downloading if the pack is inactive.
  
- A pack resumes asynchronously. To get notified when this pack resumes, observe
- KVO change notifications on this pack’s `state` key path. Alternatively, you
- can add an observer for `MGLOfflinePackProgressChangedNotification`s about this
- pack that come from the default notification center.
- 
  When a pack resumes after being suspended, it may begin by iterating over the
  already downloaded resources. As a result, the `progress` structure’s
  `countOfResourcesCompleted` field may revert to 0 before rapidly returning to
@@ -161,10 +156,9 @@ typedef struct MGLOfflinePackProgress {
 /**
  Temporarily stops downloading if the pack is active.
  
- A pack suspends asynchronously. To get notified when this pack resumes, observe
- KVO change notifications on this pack’s `state` key path. Alternatively, you
- can add an observer for `MGLOfflinePackProgressChangedNotification` about this
- pack that come from the default notification center.
+ A pack suspends asynchronously, so some network requests may be sent after this
+ method is called. Regardless, the `progress` property will not be updated until
+ `-resume` is called.
  
  If the pack previously reached a higher level of progress before being
  suspended, it may wait to suspend until it returns to that level.
diff --git a/platform/darwin/src/MGLOfflinePack.mm b/platform/darwin/src/MGLOfflinePack.mm
index 59406074e6..1f2fd95f2b 100644
--- a/platform/darwin/src/MGLOfflinePack.mm
+++ b/platform/darwin/src/MGLOfflinePack.mm
@@ -43,7 +43,9 @@ private:
 
 @end
 
-@implementation MGLOfflinePack
+@implementation MGLOfflinePack {
+    BOOL _isSuspending;
+}
 
 - (instancetype)init {
     if (self = [super init]) {
@@ -86,6 +88,8 @@ private:
 - (void)resume {
     MGLAssertOfflinePackIsValid();
     
+    self.state = MGLOfflinePackStateActive;
+    
     mbgl::DefaultFileSource *mbglFileSource = [[MGLOfflineStorage sharedOfflineStorage] mbglFileSource];
     mbglFileSource->setOfflineRegionDownloadState(*_mbglOfflineRegion, mbgl::OfflineRegionDownloadState::Active);
 }
@@ -93,6 +97,11 @@ private:
 - (void)suspend {
     MGLAssertOfflinePackIsValid();
     
+    if (self.state == MGLOfflinePackStateActive) {
+        self.state = MGLOfflinePackStateInactive;
+        _isSuspending = YES;
+    }
+    
     mbgl::DefaultFileSource *mbglFileSource = [[MGLOfflineStorage sharedOfflineStorage] mbglFileSource];
     mbglFileSource->setOfflineRegionDownloadState(*_mbglOfflineRegion, mbgl::OfflineRegionDownloadState::Inactive);
 }
@@ -117,7 +126,10 @@ private:
     
     NSAssert(_state != MGLOfflinePackStateInvalid, @"Cannot change the state of an invalid offline pack.");
     
-    _state = state;
+    if (!_isSuspending || state != MGLOfflinePackStateActive) {
+        _isSuspending = NO;
+        _state = state;
+    }
 }
 
 - (void)requestProgress {
@@ -150,6 +162,10 @@ private:
             break;
     }
     
+    if (_isSuspending) {
+        return;
+    }
+    
     MGLOfflinePackProgress progress;
     progress.countOfResourcesCompleted = status.completedResourceCount;
     progress.countOfBytesCompleted = status.completedResourceSize;