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, 52 insertions, 0 deletions

diff --git a/Firestore/core/src/firebase/firestore/util/error_apple.h b/Firestore/core/src/firebase/firestore/util/error_apple.h
new file mode 100644
index 0000000..e31cfd6
--- /dev/null
+++ b/Firestore/core/src/firebase/firestore/util/error_apple.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2018 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_ERROR_APPLE_H_
+#define FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_ERROR_APPLE_H_
+
+// Everything in this header exists for compatibility with Objective-C.
+#if __OBJC__
+
+#import <Foundation/Foundation.h>
+
+#include "Firestore/Source/Public/FIRFirestoreErrors.h"  // for FIRFirestoreErrorDomain
+#include "Firestore/core/include/firebase/firestore/firestore_errors.h"
+#include "Firestore/core/src/firebase/firestore/util/string_apple.h"
+#include "absl/strings/string_view.h"
+
+namespace firebase {
+namespace firestore {
+namespace util {
+
+// Translates a set of error_code and error_msg to an NSError.
+inline NSError* WrapNSError(const int64_t error_code,
+                            const absl::string_view error_msg) {
+  if (error_code == FirestoreErrorCode::Ok) {
+    return nil;
+  }
+  return [NSError
+      errorWithDomain:FIRFirestoreErrorDomain
+                 code:error_code
+             userInfo:@{NSLocalizedDescriptionKey : WrapNSString(error_msg)}];
+}
+
+}  // namespace util
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // __OBJC__
+
+#endif  // FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_ERROR_APPLE_H_