WIP: use expected<T, E> for passing on errors

2 files changed, 23 insertions, 20 deletions

diff --git a/platform/android/src/offline/offline_manager.cpp b/platform/android/src/offline/offline_manager.cpp
index 4960ae2845..4f94a1c3a5 100644
--- a/platform/android/src/offline/offline_manager.cpp
+++ b/platform/android/src/offline/offline_manager.cpp
@@ -26,15 +26,18 @@ void OfflineManager::listOfflineRegions(jni::JNIEnv& env_, jni::Object<FileSourc
         //Keep a shared ptr to a global reference of the callback and file source so they are not GC'd in the meanwhile
         callback = std::shared_ptr<jni::jobject>(callback_.NewGlobalRef(env_).release()->Get(), GenericGlobalRefDeleter()),
         jFileSource = std::shared_ptr<jni::jobject>(jFileSource_.NewGlobalRef(env_).release()->Get(), GenericGlobalRefDeleter())
-    ](std::exception_ptr error, mbgl::optional<std::vector<mbgl::OfflineRegion>> regions) mutable {
+    ](mbgl::expected<mbgl::OfflineRegions, std::exception_ptr> regions) mutable {
 
         // Reattach, the callback comes from a different thread
         android::UniqueEnv env = android::AttachEnv();
 
-        if (error) {
-            OfflineManager::ListOfflineRegionsCallback::onError(*env, jni::Object<ListOfflineRegionsCallback>(*callback), error);
-        } else if (regions) {
-            OfflineManager::ListOfflineRegionsCallback::onList(*env, jni::Object<FileSource>(*jFileSource), jni::Object<ListOfflineRegionsCallback>(*callback), std::move(regions));
+        if (regions) {
+            OfflineManager::ListOfflineRegionsCallback::onList(
+                *env, jni::Object<FileSource>(*jFileSource),
+                jni::Object<ListOfflineRegionsCallback>(*callback), std::move(*regions));
+        } else {
+            OfflineManager::ListOfflineRegionsCallback::onError(
+                *env, jni::Object<ListOfflineRegionsCallback>(*callback), regions.error());
         }
     });
 }
@@ -59,19 +62,19 @@ void OfflineManager::createOfflineRegion(jni::JNIEnv& env_,
         //Keep a shared ptr to a global reference of the callback and file source so they are not GC'd in the meanwhile
         callback = std::shared_ptr<jni::jobject>(callback_.NewGlobalRef(env_).release()->Get(), GenericGlobalRefDeleter()),
         jFileSource = std::shared_ptr<jni::jobject>(jFileSource_.NewGlobalRef(env_).release()->Get(), GenericGlobalRefDeleter())
-    ](std::exception_ptr error, mbgl::optional<mbgl::OfflineRegion> region) mutable {
+    ](mbgl::expected<mbgl::OfflineRegion, std::exception_ptr> region) mutable {
 
         // Reattach, the callback comes from a different thread
         android::UniqueEnv env = android::AttachEnv();
 
-        if (error) {
-            OfflineManager::CreateOfflineRegionCallback::onError(*env, jni::Object<CreateOfflineRegionCallback>(*callback), error);
-        } else if (region) {
+        if (region) {
             OfflineManager::CreateOfflineRegionCallback::onCreate(
                 *env,
                 jni::Object<FileSource>(*jFileSource),
-                jni::Object<CreateOfflineRegionCallback>(*callback), std::move(region)
+                jni::Object<CreateOfflineRegionCallback>(*callback), std::move(*region)
             );
+        } else {
+            OfflineManager::CreateOfflineRegionCallback::onError(*env, jni::Object<CreateOfflineRegionCallback>(*callback), region.error());
         }
     });
 }
diff --git a/platform/android/src/offline/offline_region.cpp b/platform/android/src/offline/offline_region.cpp
index 27de76fb00..fe4dbecf14 100644
--- a/platform/android/src/offline/offline_region.cpp
+++ b/platform/android/src/offline/offline_region.cpp
@@ -107,14 +107,14 @@ void OfflineRegion::getOfflineRegionStatus(jni::JNIEnv& env_, jni::Object<Offlin
     fileSource.getOfflineRegionStatus(*region, [
         //Ensure the object is not gc'd in the meanwhile
         callback = std::shared_ptr<jni::jobject>(callback_.NewGlobalRef(env_).release()->Get(), GenericGlobalRefDeleter())
-    ](std::exception_ptr error, mbgl::optional<mbgl::OfflineRegionStatus> status) mutable {
+    ](mbgl::expected<mbgl::OfflineRegionStatus, std::exception_ptr> status) mutable {
         // Reattach, the callback comes from a different thread
         android::UniqueEnv env = android::AttachEnv();
 
-        if (error) {
-            OfflineRegionStatusCallback::onError(*env, jni::Object<OfflineRegionStatusCallback>(*callback), error);
-        } else if (status) {
-            OfflineRegionStatusCallback::onStatus(*env, jni::Object<OfflineRegionStatusCallback>(*callback), std::move(status));
+        if (status) {
+            OfflineRegionStatusCallback::onStatus(*env, jni::Object<OfflineRegionStatusCallback>(*callback), std::move(*status));
+        } else {
+            OfflineRegionStatusCallback::onError(*env, jni::Object<OfflineRegionStatusCallback>(*callback), status.error());
         }
     });
 }
@@ -144,14 +144,14 @@ void OfflineRegion::updateOfflineRegionMetadata(jni::JNIEnv& env_, jni::Array<jn
     fileSource.updateOfflineMetadata(region->getID(), metadata, [
         //Ensure the object is not gc'd in the meanwhile
         callback = std::shared_ptr<jni::jobject>(callback_.NewGlobalRef(env_).release()->Get(), GenericGlobalRefDeleter())
-    ](std::exception_ptr error, mbgl::optional<mbgl::OfflineRegionMetadata> data) mutable {
+    ](mbgl::expected<mbgl::OfflineRegionMetadata, std::exception_ptr> data) mutable {
         // Reattach, the callback comes from a different thread
         android::UniqueEnv env = android::AttachEnv();
 
-        if (error) {
-            OfflineRegionUpdateMetadataCallback::onError(*env, jni::Object<OfflineRegionUpdateMetadataCallback>(*callback), error);
-        } else if (data) {
-            OfflineRegionUpdateMetadataCallback::onUpdate(*env, jni::Object<OfflineRegionUpdateMetadataCallback>(*callback), std::move(data));
+        if (data) {
+            OfflineRegionUpdateMetadataCallback::onUpdate(*env, jni::Object<OfflineRegionUpdateMetadataCallback>(*callback), std::move(*data));
+        } else {
+            OfflineRegionUpdateMetadataCallback::onError(*env, jni::Object<OfflineRegionUpdateMetadataCallback>(*callback), data.error());
         }
     });
 }