replacing Auth by C++ auth implementation (#802)

* lazy replacing FST(Firebase)CredentialsProvider by (Firebase)CredentialsProvider

* lazy replacing FSTUser by User

* adding error-code parameter to TokenListener

* actually use const user& instead of pointer; also add an error util

* add HashUser and pass into the unordered_map

* use User in test

* use c++ CredentialsProvider and subclass in test

* fix unit test

* use explicit capture in lambda instead of capture all by reference

* cache currentUser explicitly when reset sync engineer test driver

* objc object should be captured by value in lambda

* replacing Auth/FSTUser by C++ auth implementation

* address changes

* replacing FSTGetTokenResult by C++ Token implementation

* address changes

* fix unintentional change in merging

* patch the change in objc Auth up-stream

* somehow, the lambda-version of set-user-change-listener does not work... fallback to block

* address changes

* fix another const& v.s. dispatch bug

* fix more const& v.s. dispatch bug  zxu123 committed

* fix a bad sync line

* address changes

* address change

* address change

* fix upstream change from merge

* fix upstream changes

* Suggested fixes for cpp/port_auth (#846)

* Get rid of MockDatastore factory

This avoids the need to statically allocate (and leak) a credentials
provider

* Use absl::make_unique

std::make_unique technically does not exist until C++14.

* #include <utility> for std::move

* Use std::future for the initial user

* fix style

1 files changed, 4 insertions, 3 deletions

diff --git a/Firestore/core/src/firebase/firestore/auth/firebase_credentials_provider_apple.mm b/Firestore/core/src/firebase/firestore/auth/firebase_credentials_provider_apple.mm
index fe3cb24..1babe82 100644
--- a/Firestore/core/src/firebase/firestore/auth/firebase_credentials_provider_apple.mm
+++ b/Firestore/core/src/firebase/firestore/auth/firebase_credentials_provider_apple.mm
@@ -53,7 +53,7 @@ FirebaseCredentialsProvider::FirebaseCredentialsProvider(FIRApp* app)
 
                 NSString* user_id =
                     user_info[FIRAuthStateDidChangeInternalNotificationUIDKey];
-                User new_user(util::MakeStringView(user_id));
+                User new_user = User::FromUid(user_id);
                 if (new_user != contents->current_user) {
                   contents->current_user = new_user;
                   contents->user_counter++;
@@ -96,11 +96,12 @@ void FirebaseCredentialsProvider::GetToken(bool force_refresh,
       // Cancel the request since the user changed while the request was
       // outstanding so the response is likely for a previous user (which
       // user, we can't be sure).
-      completion({"", User::Unauthenticated()},
+      completion(Token::Invalid(), FirestoreErrorCode::Aborted,
                  "getToken aborted due to user change.");
     } else {
       completion(
-          {util::MakeStringView(token), contents->current_user},
+          Token{util::MakeStringView(token), contents->current_user},
+          error == nil ? FirestoreErrorCode::Ok : error.code,
           error == nil ? "" : util::MakeStringView(error.localizedDescription));
     }
   };