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

2 files changed, 21 insertions, 10 deletions

diff --git a/Firestore/Source/API/FIRFirestore+Internal.h b/Firestore/Source/API/FIRFirestore+Internal.h
index 7bc419a..a52533d 100644
--- a/Firestore/Source/API/FIRFirestore+Internal.h
+++ b/Firestore/Source/API/FIRFirestore+Internal.h
@@ -16,6 +16,9 @@
 
 #import "FIRFirestore.h"
 
+#include <memory>
+
+#include "Firestore/core/src/firebase/firestore/auth/credentials_provider.h"
 #include "Firestore/core/src/firebase/firestore/model/database_id.h"
 #include "absl/strings/string_view.h"
 
@@ -24,7 +27,6 @@ NS_ASSUME_NONNULL_BEGIN
 @class FSTDispatchQueue;
 @class FSTFirestoreClient;
 @class FSTUserDataConverter;
-@protocol FSTCredentialsProvider;
 
 @interface FIRFirestore (/* Init */)
 
@@ -35,7 +37,8 @@ NS_ASSUME_NONNULL_BEGIN
 - (instancetype)initWithProjectID:(const absl::string_view)projectID
                          database:(const absl::string_view)database
                    persistenceKey:(NSString *)persistenceKey
-              credentialsProvider:(id<FSTCredentialsProvider>)credentialsProvider
+              credentialsProvider:(std::unique_ptr<firebase::firestore::auth::CredentialsProvider>)
+                                      credentialsProvider
               workerDispatchQueue:(FSTDispatchQueue *)workerDispatchQueue
                       firebaseApp:(FIRApp *)app;
 
diff --git a/Firestore/Source/API/FIRFirestore.mm b/Firestore/Source/API/FIRFirestore.mm
index ce8f8ab..eff0605 100644
--- a/Firestore/Source/API/FIRFirestore.mm
+++ b/Firestore/Source/API/FIRFirestore.mm
@@ -16,6 +16,10 @@
 
 #import "FIRFirestore.h"
 
+#include <memory>
+#include <utility>
+
+#import <FirebaseCore/FIRApp.h>
 #import <FirebaseCore/FIRAppInternal.h>
 #import <FirebaseCore/FIRLogger.h>
 #import <FirebaseCore/FIROptions.h>
@@ -28,7 +32,6 @@
 #import "Firestore/Source/API/FIRWriteBatch+Internal.h"
 #import "Firestore/Source/API/FSTUserDataConverter.h"
 
-#import "Firestore/Source/Auth/FSTCredentialsProvider.h"
 #import "Firestore/Source/Core/FSTFirestoreClient.h"
 #import "Firestore/Source/Model/FSTDocumentKey.h"
 #import "Firestore/Source/Model/FSTPath.h"
@@ -37,11 +40,16 @@
 #import "Firestore/Source/Util/FSTLogger.h"
 #import "Firestore/Source/Util/FSTUsageValidation.h"
 
+#include "Firestore/core/src/firebase/firestore/auth/credentials_provider.h"
+#include "Firestore/core/src/firebase/firestore/auth/firebase_credentials_provider_apple.h"
 #include "Firestore/core/src/firebase/firestore/core/database_info.h"
 #include "Firestore/core/src/firebase/firestore/model/database_id.h"
 #include "Firestore/core/src/firebase/firestore/util/string_apple.h"
+#include "absl/memory/memory.h"
 
 namespace util = firebase::firestore::util;
+using firebase::firestore::auth::CredentialsProvider;
+using firebase::firestore::auth::FirebaseCredentialsProvider;
 using firebase::firestore::core::DatabaseInfo;
 using firebase::firestore::model::DatabaseId;
 
@@ -52,10 +60,10 @@ extern "C" NSString *const FIRFirestoreErrorDomain = @"FIRFirestoreErrorDomain";
 @interface FIRFirestore () {
   /** The actual owned DatabaseId instance is allocated in FIRFirestore. */
   DatabaseId _databaseID;
+  std::unique_ptr<CredentialsProvider> _credentialsProvider;
 }
 
 @property(nonatomic, strong) NSString *persistenceKey;
-@property(nonatomic, strong) id<FSTCredentialsProvider> credentialsProvider;
 @property(nonatomic, strong) FSTDispatchQueue *workerDispatchQueue;
 
 // Note that `client` is updated after initialization, but marking this readwrite would generate an
@@ -152,15 +160,15 @@ extern "C" NSString *const FIRFirestoreErrorDomain = @"FIRFirestoreErrorDomain";
       FSTDispatchQueue *workerDispatchQueue = [FSTDispatchQueue
           queueWith:dispatch_queue_create("com.google.firebase.firestore", DISPATCH_QUEUE_SERIAL)];
 
-      id<FSTCredentialsProvider> credentialsProvider;
-      credentialsProvider = [[FSTFirebaseCredentialsProvider alloc] initWithApp:app];
+      std::unique_ptr<CredentialsProvider> credentials_provider =
+          absl::make_unique<FirebaseCredentialsProvider>(app);
 
       NSString *persistenceKey = app.name;
 
       firestore = [[FIRFirestore alloc] initWithProjectID:util::MakeStringView(projectID)
                                                  database:util::MakeStringView(database)
                                            persistenceKey:persistenceKey
-                                      credentialsProvider:credentialsProvider
+                                      credentialsProvider:std::move(credentials_provider)
                                       workerDispatchQueue:workerDispatchQueue
                                               firebaseApp:app];
       instances[key] = firestore;
@@ -173,7 +181,7 @@ extern "C" NSString *const FIRFirestoreErrorDomain = @"FIRFirestoreErrorDomain";
 - (instancetype)initWithProjectID:(const absl::string_view)projectID
                          database:(const absl::string_view)database
                    persistenceKey:(NSString *)persistenceKey
-              credentialsProvider:(id<FSTCredentialsProvider>)credentialsProvider
+              credentialsProvider:(std::unique_ptr<CredentialsProvider>)credentialsProvider
               workerDispatchQueue:(FSTDispatchQueue *)workerDispatchQueue
                       firebaseApp:(FIRApp *)app {
   if (self = [super init]) {
@@ -190,7 +198,7 @@ extern "C" NSString *const FIRFirestoreErrorDomain = @"FIRFirestoreErrorDomain";
     _dataConverter =
         [[FSTUserDataConverter alloc] initWithDatabaseID:&_databaseID preConverter:block];
     _persistenceKey = persistenceKey;
-    _credentialsProvider = credentialsProvider;
+    _credentialsProvider = std::move(credentialsProvider);
     _workerDispatchQueue = workerDispatchQueue;
     _app = app;
     _settings = [[FIRFirestoreSettings alloc] init];
@@ -241,7 +249,7 @@ extern "C" NSString *const FIRFirestoreErrorDomain = @"FIRFirestoreErrorDomain";
 
       _client = [FSTFirestoreClient clientWithDatabaseInfo:database_info
                                             usePersistence:_settings.persistenceEnabled
-                                       credentialsProvider:_credentialsProvider
+                                       credentialsProvider:_credentialsProvider.get()
                                          userDispatchQueue:userDispatchQueue
                                        workerDispatchQueue:_workerDispatchQueue];
     }