Implement Firestore DatabaseInfo and port both Database{Id,Info} C++ to the iOS code (#738)

* implement Firestore DatabaseInfo in C++

* temporary stash changes; blocking on the massive renaming of .m to .mm

* add database_info_test to project

* finish port DatabaseId and fix style, modular fixing DatabaseInfo

* port DatabaseInfo

* remove FSTDatabase{ID,Info} and their tests from project

* fix unit test

* use namespace alias

* use namespace alias, leftover

* address more changes

* refactoring to use raw pointer instead of value for property

* address changes

* remove self->

* fix style

* remove the name suffix Alloc

* fix a bug

5 files changed, 33 insertions, 142 deletions

diff --git a/Firestore/Source/Core/FSTDatabaseInfo.h b/Firestore/Source/Core/FSTDatabaseInfo.h
deleted file mode 100644
index fae884f..0000000
--- a/Firestore/Source/Core/FSTDatabaseInfo.h
+++ /dev/null
@@ -1,55 +0,0 @@
-/*
- * Copyright 2017 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.
- */
-
-#import <Foundation/Foundation.h>
-
-@class FSTDatabaseID;
-
-NS_ASSUME_NONNULL_BEGIN
-
-/** FSTDatabaseInfo contains data about the database. */
-@interface FSTDatabaseInfo : NSObject
-
-/**
- * Creates and returns a new FSTDatabaseInfo.
- *
- * @param databaseID The project/database to use.
- * @param persistenceKey A unique identifier for this Firestore's local storage. Usually derived
- *     from -[FIRApp appName].
- * @param host The hostname of the datastore backend.
- * @param sslEnabled Whether to use SSL when connecting.
- * @return A new instance of FSTDatabaseInfo.
- */
-+ (instancetype)databaseInfoWithDatabaseID:(FSTDatabaseID *)databaseID
-                            persistenceKey:(NSString *)persistenceKey
-                                      host:(NSString *)host
-                                sslEnabled:(BOOL)sslEnabled;
-
-/** The database info. */
-@property(nonatomic, strong, readonly) FSTDatabaseID *databaseID;
-
-/** The application name, taken from FIRApp. */
-@property(nonatomic, copy, readonly) NSString *persistenceKey;
-
-/** The hostname of the backend. */
-@property(nonatomic, copy, readonly) NSString *host;
-
-/** Whether to use SSL when connecting. */
-@property(nonatomic, readonly, getter=isSSLEnabled) BOOL sslEnabled;
-
-@end
-
-NS_ASSUME_NONNULL_END
diff --git a/Firestore/Source/Core/FSTDatabaseInfo.mm b/Firestore/Source/Core/FSTDatabaseInfo.mm
deleted file mode 100644
index 2dbe61a..0000000
--- a/Firestore/Source/Core/FSTDatabaseInfo.mm
+++ /dev/null
@@ -1,70 +0,0 @@
-/*
- * Copyright 2017 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.
- */
-
-#import "Firestore/Source/Core/FSTDatabaseInfo.h"
-
-#import "Firestore/Source/Model/FSTDatabaseID.h"
-
-NS_ASSUME_NONNULL_BEGIN
-
-#pragma mark - FSTDatabaseInfo
-
-@implementation FSTDatabaseInfo
-
-#pragma mark - Constructors
-
-+ (instancetype)databaseInfoWithDatabaseID:(FSTDatabaseID *)databaseID
-                            persistenceKey:(NSString *)persistenceKey
-                                      host:(NSString *)host
-                                sslEnabled:(BOOL)sslEnabled {
-  return [[FSTDatabaseInfo alloc] initWithDatabaseID:databaseID
-                                      persistenceKey:persistenceKey
-                                                host:host
-                                          sslEnabled:sslEnabled];
-}
-
-/**
- * Designated initializer.
- *
- * @param databaseID The database in the datastore.
- * @param persistenceKey A unique identifier for this Firestore's local storage. Usually derived
- *     from -[FIRApp appName].
- * @param host The Firestore server hostname.
- * @param sslEnabled Whether to use SSL when connecting.
- */
-- (instancetype)initWithDatabaseID:(FSTDatabaseID *)databaseID
-                    persistenceKey:(NSString *)persistenceKey
-                              host:(NSString *)host
-                        sslEnabled:(BOOL)sslEnabled {
-  if (self = [super init]) {
-    _databaseID = databaseID;
-    _persistenceKey = [persistenceKey copy];
-    _host = [host copy];
-    _sslEnabled = sslEnabled;
-  }
-  return self;
-}
-
-#pragma mark - NSObject methods
-
-- (NSString *)description {
-  return [NSString
-      stringWithFormat:@"<FSTDatabaseInfo: databaseID:%@ host:%@>", self.databaseID, self.host];
-}
-
-@end
-
-NS_ASSUME_NONNULL_END
diff --git a/Firestore/Source/Core/FSTFirestoreClient.h b/Firestore/Source/Core/FSTFirestoreClient.h
index 0ecf2f6..56101ab 100644
--- a/Firestore/Source/Core/FSTFirestoreClient.h
+++ b/Firestore/Source/Core/FSTFirestoreClient.h
@@ -20,8 +20,9 @@
 #import "Firestore/Source/Core/FSTViewSnapshot.h"
 #import "Firestore/Source/Remote/FSTRemoteStore.h"
 
-@class FSTDatabaseID;
-@class FSTDatabaseInfo;
+#include "Firestore/core/src/firebase/firestore/core/database_info.h"
+#include "Firestore/core/src/firebase/firestore/model/database_id.h"
+
 @class FSTDispatchQueue;
 @class FSTDocument;
 @class FSTListenOptions;
@@ -45,7 +46,7 @@ NS_ASSUME_NONNULL_BEGIN
  *
  * All callbacks and events will be triggered on the provided userDispatchQueue.
  */
-+ (instancetype)clientWithDatabaseInfo:(FSTDatabaseInfo *)databaseInfo
++ (instancetype)clientWithDatabaseInfo:(const firebase::firestore::core::DatabaseInfo &)databaseInfo
                         usePersistence:(BOOL)usePersistence
                    credentialsProvider:(id<FSTCredentialsProvider>)credentialsProvider
                      userDispatchQueue:(FSTDispatchQueue *)userDispatchQueue
@@ -80,7 +81,8 @@ NS_ASSUME_NONNULL_BEGIN
                     completion:(FSTVoidIDErrorBlock)completion;
 
 /** The database ID of the databaseInfo this client was initialized with. */
-@property(nonatomic, strong, readonly) FSTDatabaseID *databaseID;
+// Ownes a DatabaseInfo instance, which contains the id here.
+@property(nonatomic, assign, readonly) const firebase::firestore::model::DatabaseId *databaseID;
 
 /**
  * Dispatch queue for user callbacks / events. This will often be the "Main Dispatch Queue" of the
diff --git a/Firestore/Source/Core/FSTFirestoreClient.mm b/Firestore/Source/Core/FSTFirestoreClient.mm
index 5986b5b..1961460 100644
--- a/Firestore/Source/Core/FSTFirestoreClient.mm
+++ b/Firestore/Source/Core/FSTFirestoreClient.mm
@@ -17,7 +17,6 @@
 #import "Firestore/Source/Core/FSTFirestoreClient.h"
 
 #import "Firestore/Source/Auth/FSTCredentialsProvider.h"
-#import "Firestore/Source/Core/FSTDatabaseInfo.h"
 #import "Firestore/Source/Core/FSTEventManager.h"
 #import "Firestore/Source/Core/FSTSyncEngine.h"
 #import "Firestore/Source/Core/FSTTransaction.h"
@@ -35,16 +34,26 @@
 #import "Firestore/Source/Util/FSTDispatchQueue.h"
 #import "Firestore/Source/Util/FSTLogger.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"
+
+using firebase::firestore::core::DatabaseInfo;
+using firebase::firestore::model::DatabaseId;
+
 NS_ASSUME_NONNULL_BEGIN
 
-@interface FSTFirestoreClient ()
-- (instancetype)initWithDatabaseInfo:(FSTDatabaseInfo *)databaseInfo
+@interface FSTFirestoreClient () {
+  DatabaseInfo _databaseInfo;
+}
+
+- (instancetype)initWithDatabaseInfo:(const DatabaseInfo &)databaseInfo
                       usePersistence:(BOOL)usePersistence
                  credentialsProvider:(id<FSTCredentialsProvider>)credentialsProvider
                    userDispatchQueue:(FSTDispatchQueue *)userDispatchQueue
                  workerDispatchQueue:(FSTDispatchQueue *)queue NS_DESIGNATED_INITIALIZER;
 
-@property(nonatomic, strong, readonly) FSTDatabaseInfo *databaseInfo;
+@property(nonatomic, assign, readonly) const DatabaseInfo *databaseInfo;
 @property(nonatomic, strong, readonly) FSTEventManager *eventManager;
 @property(nonatomic, strong, readonly) id<FSTPersistence> persistence;
 @property(nonatomic, strong, readonly) FSTSyncEngine *syncEngine;
@@ -65,7 +74,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 @implementation FSTFirestoreClient
 
-+ (instancetype)clientWithDatabaseInfo:(FSTDatabaseInfo *)databaseInfo
++ (instancetype)clientWithDatabaseInfo:(const DatabaseInfo &)databaseInfo
                         usePersistence:(BOOL)usePersistence
                    credentialsProvider:(id<FSTCredentialsProvider>)credentialsProvider
                      userDispatchQueue:(FSTDispatchQueue *)userDispatchQueue
@@ -77,7 +86,7 @@ NS_ASSUME_NONNULL_BEGIN
                                       workerDispatchQueue:workerDispatchQueue];
 }
 
-- (instancetype)initWithDatabaseInfo:(FSTDatabaseInfo *)databaseInfo
+- (instancetype)initWithDatabaseInfo:(const DatabaseInfo &)databaseInfo
                       usePersistence:(BOOL)usePersistence
                  credentialsProvider:(id<FSTCredentialsProvider>)credentialsProvider
                    userDispatchQueue:(FSTDispatchQueue *)userDispatchQueue
@@ -130,11 +139,11 @@ NS_ASSUME_NONNULL_BEGIN
     // enabled.
     garbageCollector = [[FSTNoOpGarbageCollector alloc] init];
 
-    NSString *dir = [FSTLevelDB storageDirectoryForDatabaseInfo:self.databaseInfo
+    NSString *dir = [FSTLevelDB storageDirectoryForDatabaseInfo:*self.databaseInfo
                                              documentsDirectory:[FSTLevelDB documentsDirectory]];
 
     FSTSerializerBeta *remoteSerializer =
-        [[FSTSerializerBeta alloc] initWithDatabaseID:self.databaseInfo.databaseID];
+        [[FSTSerializerBeta alloc] initWithDatabaseID:&self.databaseInfo->database_id()];
     FSTLocalSerializer *serializer =
         [[FSTLocalSerializer alloc] initWithRemoteSerializer:remoteSerializer];
 
@@ -291,8 +300,12 @@ NS_ASSUME_NONNULL_BEGIN
   }];
 }
 
-- (FSTDatabaseID *)databaseID {
-  return self.databaseInfo.databaseID;
+- (const DatabaseInfo *)databaseInfo {
+  return &_databaseInfo;
+}
+
+- (const DatabaseId *)databaseID {
+  return &_databaseInfo.database_id();
 }
 
 @end
diff --git a/Firestore/Source/Core/FSTSyncEngine.mm b/Firestore/Source/Core/FSTSyncEngine.mm
index d82cc99..d6ee956 100644
--- a/Firestore/Source/Core/FSTSyncEngine.mm
+++ b/Firestore/Source/Core/FSTSyncEngine.mm
@@ -42,6 +42,8 @@
 
 #include "Firestore/core/src/firebase/firestore/core/target_id_generator.h"
 
+using firebase::firestore::core::TargetIdGenerator;
+
 NS_ASSUME_NONNULL_BEGIN
 
 // Limbo documents don't use persistence, and are eagerly GC'd. So, listens for them don't need
@@ -148,7 +150,7 @@ static const FSTListenSequenceNumber kIrrelevantSequenceNumber = -1;
 
 @implementation FSTSyncEngine {
   /** Used for creating the FSTTargetIDs for the listens used to resolve limbo documents. */
-  firebase::firestore::core::TargetIdGenerator _targetIdGenerator;
+  TargetIdGenerator _targetIdGenerator;
 }
 
 - (instancetype)initWithLocalStore:(FSTLocalStore *)localStore
@@ -168,8 +170,7 @@ static const FSTListenSequenceNumber kIrrelevantSequenceNumber = -1;
     [_limboCollector addGarbageSource:_limboDocumentRefs];
 
     _mutationCompletionBlocks = [NSMutableDictionary dictionary];
-    _targetIdGenerator =
-        firebase::firestore::core::TargetIdGenerator::SyncEngineTargetIdGenerator(0);
+    _targetIdGenerator = TargetIdGenerator::SyncEngineTargetIdGenerator(0);
     _currentUser = initialUser;
   }
   return self;