publish waitForPendingWrites (#3690)

* publish waitForPendingWrites

* add change log

* move impl out of internal

Author: wu-hui

Firestore/CHANGELOG.md

@@ -2,6 +2,9 @@
 - [changed] Transactions now perform exponential backoff before retrying.
   This means transactions on highly contended documents are more likely to
   succeed.
+- [feature] Added a `waitForPendingWrites()` method to `FIRFirestore` class
+  which allows users to wait on a promise that resolves when all pending
+  writes are acknowledged by the Firestore backend.
 
 # v1.4.5
 - [fixed] Fixed a crash that would happen when changing networks or going from

Firestore/Source/API/FIRFirestore+Internal.h

@@ -90,22 +90,6 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)shutdownInternalWithCompletion:(nullable void (^)(NSError *_Nullable error))completion;
 
-/**
- * Waits until all currently pending writes for the active user have been acknowledged by the
- * backend.
- *
- * The completion block is called immediately without error if there are no outstanding writes.
- * Otherwise, the completion block is called when all previously issued writes (including those
- * written in a previous app session) have been acknowledged by the backend. The completion
- * block does not wait for writes that were added after the method is called. If you
- * wish to wait for additional writes, you have to call `waitForPendingWritesWithCompletion`
- * again.
- *
- * Any outstanding `waitForPendingWritesWithCompletion` completion blocks are called with an
- * error during user change.
- */
-- (void)waitForPendingWritesWithCompletion:(void (^)(NSError *_Nullable error))completion;
-
 - (const std::shared_ptr<util::AsyncQueue> &)workerQueue;
 
 @property(nonatomic, assign, readonly) std::shared_ptr<api::Firestore> wrapped;

Firestore/Source/API/FIRFirestore.mm

@@ -277,6 +277,10 @@ - (void)clearPersistenceWithCompletion:(nullable void (^)(NSError *_Nullable err
   _firestore->ClearPersistence(util::MakeCallback(completion));
 }
 
+- (void)waitForPendingWritesWithCompletion:(void (^)(NSError *_Nullable error))completion {
+  _firestore->WaitForPendingWrites(util::MakeCallback(completion));
+}
+
 @end
 
 @implementation FIRFirestore (Internal)
@@ -314,10 +318,6 @@ - (void)shutdownWithCompletion:(nullable void (^)(NSError *_Nullable error))comp
   [self shutdownInternalWithCompletion:completion];
 }
 
-- (void)waitForPendingWritesWithCompletion:(void (^)(NSError *_Nullable error))completion {
-  _firestore->WaitForPendingWrites(util::MakeCallback(completion));
-}
-
 @end
 
 NS_ASSUME_NONNULL_END

Firestore/Source/Public/FIRFirestore.h

@@ -192,6 +192,22 @@ NS_SWIFT_NAME(Firestore)
  */
 - (void)clearPersistenceWithCompletion:(nullable void (^)(NSError *_Nullable error))completion;
 
+/**
+ * Waits until all currently pending writes for the active user have been acknowledged by the
+ * backend.
+ *
+ * The completion block is called immediately without error if there are no outstanding writes.
+ * Otherwise, the completion block is called when all previously issued writes (including those
+ * written in a previous app session) have been acknowledged by the backend. The completion
+ * block does not wait for writes that were added after the method is called. If you
+ * wish to wait for additional writes, you have to call `waitForPendingWritesWithCompletion`
+ * again.
+ *
+ * Any outstanding `waitForPendingWritesWithCompletion` completion blocks are called with an
+ * error during user change.
+ */
+- (void)waitForPendingWritesWithCompletion:(void (^)(NSError *_Nullable error))completion;
+
 @end
 
 NS_ASSUME_NONNULL_END