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

1 files changed, 16 insertions, 8 deletions

diff --git a/Firestore/Source/API/FSTUserDataConverter.mm b/Firestore/Source/API/FSTUserDataConverter.mm
index 414aadb..80d4625 100644
--- a/Firestore/Source/API/FSTUserDataConverter.mm
+++ b/Firestore/Source/API/FSTUserDataConverter.mm
@@ -23,7 +23,6 @@
 #import "Firestore/Source/API/FIRFirestore+Internal.h"
 #import "Firestore/Source/API/FIRSetOptions+Internal.h"
 #import "Firestore/Source/Core/FSTTimestamp.h"
-#import "Firestore/Source/Model/FSTDatabaseID.h"
 #import "Firestore/Source/Model/FSTDocumentKey.h"
 #import "Firestore/Source/Model/FSTFieldValue.h"
 #import "Firestore/Source/Model/FSTMutation.h"
@@ -31,6 +30,12 @@
 #import "Firestore/Source/Util/FSTAssert.h"
 #import "Firestore/Source/Util/FSTUsageValidation.h"
 
+#include "Firestore/core/src/firebase/firestore/model/database_id.h"
+#include "Firestore/core/src/firebase/firestore/util/string_apple.h"
+
+namespace util = firebase::firestore::util;
+using firebase::firestore::model::DatabaseId;
+
 NS_ASSUME_NONNULL_BEGIN
 
 static NSString *const RESERVED_FIELD_DESIGNATOR = @"__";
@@ -271,7 +276,7 @@ typedef NS_ENUM(NSInteger, FSTUserDataSource) {
 
 @implementation FSTDocumentKeyReference
 
-- (instancetype)initWithKey:(FSTDocumentKey *)key databaseID:(FSTDatabaseID *)databaseID {
+- (instancetype)initWithKey:(FSTDocumentKey *)key databaseID:(const DatabaseId *)databaseID {
   self = [super init];
   if (self) {
     _key = key;
@@ -285,13 +290,14 @@ typedef NS_ENUM(NSInteger, FSTUserDataSource) {
 #pragma mark - FSTUserDataConverter
 
 @interface FSTUserDataConverter ()
-@property(strong, nonatomic, readonly) FSTDatabaseID *databaseID;
+// Does not own the DatabaseId instance.
+@property(assign, nonatomic, readonly) const DatabaseId *databaseID;
 @property(strong, nonatomic, readonly) FSTPreConverterBlock preConverter;
 @end
 
 @implementation FSTUserDataConverter
 
-- (instancetype)initWithDatabaseID:(FSTDatabaseID *)databaseID
+- (instancetype)initWithDatabaseID:(const DatabaseId *)databaseID
                       preConverter:(FSTPreConverterBlock)preConverter {
   self = [super init];
   if (self) {
@@ -540,12 +546,14 @@ typedef NS_ENUM(NSInteger, FSTUserDataSource) {
 
   } else if ([input isKindOfClass:[FSTDocumentKeyReference class]]) {
     FSTDocumentKeyReference *reference = input;
-    if (![reference.databaseID isEqual:self.databaseID]) {
-      FSTDatabaseID *other = reference.databaseID;
+    if (*reference.databaseID != *self.databaseID) {
+      const DatabaseId *other = reference.databaseID;
       FSTThrowInvalidArgument(
           @"Document Reference is for database %@/%@ but should be for database %@/%@%@",
-          other.projectID, other.databaseID, self.databaseID.projectID, self.databaseID.databaseID,
-          [context fieldDescription]);
+          util::WrapNSStringNoCopy(other->project_id()),
+          util::WrapNSStringNoCopy(other->database_id()),
+          util::WrapNSStringNoCopy(self.databaseID->project_id()),
+          util::WrapNSStringNoCopy(self.databaseID->database_id()), [context fieldDescription]);
     }
     return [FSTReferenceValue referenceValue:reference.key databaseID:self.databaseID];