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, 33 insertions, 12 deletions

diff --git a/Firestore/Source/Remote/FSTSerializerBeta.mm b/Firestore/Source/Remote/FSTSerializerBeta.mm
index cf200ca..35ab637 100644
--- a/Firestore/Source/Remote/FSTSerializerBeta.mm
+++ b/Firestore/Source/Remote/FSTSerializerBeta.mm
@@ -34,7 +34,6 @@
 #import "Firestore/Source/Core/FSTSnapshotVersion.h"
 #import "Firestore/Source/Core/FSTTimestamp.h"
 #import "Firestore/Source/Local/FSTQueryData.h"
-#import "Firestore/Source/Model/FSTDatabaseID.h"
 #import "Firestore/Source/Model/FSTDocument.h"
 #import "Firestore/Source/Model/FSTDocumentKey.h"
 #import "Firestore/Source/Model/FSTFieldValue.h"
@@ -45,15 +44,22 @@
 #import "Firestore/Source/Remote/FSTWatchChange.h"
 #import "Firestore/Source/Util/FSTAssert.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
 
 @interface FSTSerializerBeta ()
-@property(nonatomic, strong, readonly) FSTDatabaseID *databaseID;
+// Does not own this DatabaseId.
+@property(nonatomic, assign, readonly) const DatabaseId *databaseID;
 @end
 
 @implementation FSTSerializerBeta
 
-- (instancetype)initWithDatabaseID:(FSTDatabaseID *)databaseID {
+- (instancetype)initWithDatabaseID:(const DatabaseId *)databaseID {
   self = [super init];
   if (self) {
     _databaseID = databaseID;
@@ -103,14 +109,16 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (FSTDocumentKey *)decodedDocumentKey:(NSString *)name {
   FSTResourcePath *path = [self decodedResourcePathWithDatabaseID:name];
-  FSTAssert([[path segmentAtIndex:1] isEqualToString:self.databaseID.projectID],
+  FSTAssert([[path segmentAtIndex:1]
+                isEqualToString:util::WrapNSStringNoCopy(self.databaseID->project_id())],
             @"Tried to deserialize key from different project.");
-  FSTAssert([[path segmentAtIndex:3] isEqualToString:self.databaseID.databaseID],
+  FSTAssert([[path segmentAtIndex:3]
+                isEqualToString:util::WrapNSStringNoCopy(self.databaseID->database_id())],
             @"Tried to deserialize key from different datbase.");
   return [FSTDocumentKey keyWithPath:[self localResourcePathForQualifiedResourcePath:path]];
 }
 
-- (NSString *)encodedResourcePathForDatabaseID:(FSTDatabaseID *)databaseID
+- (NSString *)encodedResourcePathForDatabaseID:(const DatabaseId *)databaseID
                                           path:(FSTResourcePath *)path {
   return [[[[self encodedResourcePathForDatabaseID:databaseID] pathByAppendingSegment:@"documents"]
       pathByAppendingPath:path] canonicalString];
@@ -139,9 +147,11 @@ NS_ASSUME_NONNULL_BEGIN
   }
 }
 
-- (FSTResourcePath *)encodedResourcePathForDatabaseID:(FSTDatabaseID *)databaseID {
-  return [FSTResourcePath
-      pathWithSegments:@[ @"projects", databaseID.projectID, @"databases", databaseID.databaseID ]];
+- (FSTResourcePath *)encodedResourcePathForDatabaseID:(const DatabaseId *)databaseID {
+  return [FSTResourcePath pathWithSegments:@[
+    @"projects", util::WrapNSStringNoCopy(databaseID->project_id()), @"databases",
+    util::WrapNSStringNoCopy(databaseID->database_id())
+  ]];
 }
 
 - (FSTResourcePath *)localResourcePathForQualifiedResourcePath:(FSTResourcePath *)resourceName {
@@ -295,8 +305,13 @@ NS_ASSUME_NONNULL_BEGIN
   return result;
 }
 
-- (GCFSValue *)encodedReferenceValueForDatabaseID:(FSTDatabaseID *)databaseID
+- (GCFSValue *)encodedReferenceValueForDatabaseID:(const DatabaseId *)databaseID
                                               key:(FSTDocumentKey *)key {
+  FSTAssert(*databaseID == *self.databaseID, @"Database %@:%@ cannot encode reference from %@:%@",
+            util::WrapNSStringNoCopy(self.databaseID->project_id()),
+            util::WrapNSStringNoCopy(self.databaseID->database_id()),
+            util::WrapNSStringNoCopy(databaseID->project_id()),
+            util::WrapNSStringNoCopy(databaseID->database_id()));
   GCFSValue *result = [GCFSValue message];
   result.referenceValue = [self encodedResourcePathForDatabaseID:databaseID path:key.path];
   return result;
@@ -306,10 +321,16 @@ NS_ASSUME_NONNULL_BEGIN
   FSTResourcePath *path = [self decodedResourcePathWithDatabaseID:resourceName];
   NSString *project = [path segmentAtIndex:1];
   NSString *database = [path segmentAtIndex:3];
-  FSTDatabaseID *databaseID = [FSTDatabaseID databaseIDWithProject:project database:database];
   FSTDocumentKey *key =
       [FSTDocumentKey keyWithPath:[self localResourcePathForQualifiedResourcePath:path]];
-  return [FSTReferenceValue referenceValue:key databaseID:databaseID];
+
+  const DatabaseId database_id(util::MakeStringView(project), util::MakeStringView(database));
+  FSTAssert(database_id == *self.databaseID, @"Database %@:%@ cannot encode reference from %@:%@",
+            util::WrapNSStringNoCopy(self.databaseID->project_id()),
+            util::WrapNSStringNoCopy(self.databaseID->database_id()),
+            util::WrapNSStringNoCopy(database_id.project_id()),
+            util::WrapNSStringNoCopy(database_id.database_id()));
+  return [FSTReferenceValue referenceValue:key databaseID:self.databaseID];
 }
 
 - (GCFSArrayValue *)encodedArrayValue:(FSTArrayValue *)arrayValue {