4 files changed, 22 insertions, 19 deletions
diff --git a/Firestore/Source/API/FIRCollectionReference.mm b/Firestore/Source/API/FIRCollectionReference.mm
index cb7b61a..9560d13 100644
--- a/Firestore/Source/API/FIRCollectionReference.mm
+++ b/Firestore/Source/API/FIRCollectionReference.mm
@@ -101,8 +101,7 @@ NS_ASSUME_NONNULL_BEGIN
   if (parentPath.empty()) {
     return nil;
   } else {
-    FSTDocumentKey *key =
-        [FSTDocumentKey keyWithPath:[FSTResourcePath resourcePathWithCPPResourcePath:parentPath]];
+    FSTDocumentKey *key = [FSTDocumentKey keyWithPath:parentPath];
     return [FIRDocumentReference referenceWithKey:key firestore:self.firestore];
   }
 }
@@ -135,9 +134,7 @@ NS_ASSUME_NONNULL_BEGIN
 }
 
 - (FIRDocumentReference *)documentWithAutoID {
-  const ResourcePath path = self.query.path.Append(CreateAutoId());
-  FSTDocumentKey *key =
-      [FSTDocumentKey keyWithPath:[FSTResourcePath resourcePathWithCPPResourcePath:path]];
+  FSTDocumentKey *key = [FSTDocumentKey keyWithPath:self.query.path.Append(CreateAutoId())];
   return [FIRDocumentReference referenceWithKey:key firestore:self.firestore];
 }
 
diff --git a/Firestore/Source/API/FIRDocumentReference.mm b/Firestore/Source/API/FIRDocumentReference.mm
index b1a5d49..cc14af5 100644
--- a/Firestore/Source/API/FIRDocumentReference.mm
+++ b/Firestore/Source/API/FIRDocumentReference.mm
@@ -39,6 +39,12 @@
 #import "Firestore/Source/Util/FSTAsyncQueryListener.h"
 #import "Firestore/Source/Util/FSTUsageValidation.h"
 
+#include "Firestore/core/src/firebase/firestore/model/resource_path.h"
+#include "Firestore/core/src/firebase/firestore/util/string_apple.h"
+
+namespace util = firebase::firestore::util;
+using firebase::firestore::model::ResourcePath;
+
 NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark - FIRDocumentListenOptions
@@ -93,7 +99,8 @@ NS_ASSUME_NONNULL_BEGIN
         path.canonicalString, path.length);
   }
   return
-      [FIRDocumentReference referenceWithKey:[FSTDocumentKey keyWithPath:path] firestore:firestore];
+      [FIRDocumentReference referenceWithKey:[FSTDocumentKey keyWithPath:[path toCPPResourcePath]]
+                                   firestore:firestore];
 }
 
 + (instancetype)referenceWithKey:(FSTDocumentKey *)key firestore:(FIRFirestore *)firestore {
@@ -136,16 +143,17 @@ NS_ASSUME_NONNULL_BEGIN
 #pragma mark - Public Methods
 
 - (NSString *)documentID {
-  return [self.key.path lastSegment];
+  return util::WrapNSString(self.key.path.last_segment());
 }
 
 - (FIRCollectionReference *)parent {
-  FSTResourcePath *parentPath = [self.key.path pathByRemovingLastSegment];
-  return [FIRCollectionReference referenceWithPath:parentPath firestore:self.firestore];
+  return [FIRCollectionReference
+      referenceWithPath:[FSTResourcePath resourcePathWithCPPResourcePath:self.key.path.PopLast()]
+              firestore:self.firestore];
 }
 
 - (NSString *)path {
-  return [self.key.path canonicalString];
+  return util::WrapNSString(self.key.path.CanonicalString());
 }
 
 - (FIRCollectionReference *)collectionWithPath:(NSString *)collectionPath {
@@ -153,7 +161,8 @@ NS_ASSUME_NONNULL_BEGIN
     FSTThrowInvalidArgument(@"Collection path cannot be nil.");
   }
   FSTResourcePath *subPath = [FSTResourcePath pathWithString:collectionPath];
-  FSTResourcePath *path = [self.key.path pathByAppendingPath:subPath];
+  FSTResourcePath *path = [FSTResourcePath
+      resourcePathWithCPPResourcePath:self.key.path.Append([subPath toCPPResourcePath])];
   return [FIRCollectionReference referenceWithPath:path firestore:self.firestore];
 }
 
@@ -266,7 +275,7 @@ NS_ASSUME_NONNULL_BEGIN
 addSnapshotListenerInternalWithOptions:(FSTListenOptions *)internalOptions
                               listener:(FIRDocumentSnapshotBlock)listener {
   FIRFirestore *firestore = self.firestore;
-  FSTQuery *query = [FSTQuery queryWithPath:[self.key.path toCPPResourcePath]];
+  FSTQuery *query = [FSTQuery queryWithPath:self.key.path];
   FSTDocumentKey *key = self.key;
 
   FSTViewSnapshotHandler snapshotHandler = ^(FSTViewSnapshot *snapshot, NSError *error) {
diff --git a/Firestore/Source/API/FIRDocumentSnapshot.mm b/Firestore/Source/API/FIRDocumentSnapshot.mm
index ddf4cca..8e731da 100644
--- a/Firestore/Source/API/FIRDocumentSnapshot.mm
+++ b/Firestore/Source/API/FIRDocumentSnapshot.mm
@@ -122,7 +122,7 @@ NS_ASSUME_NONNULL_BEGIN
 }
 
 - (NSString *)documentID {
-  return [self.internalKey.path lastSegment];
+  return util::WrapNSString(self.internalKey.path.last_segment());
 }
 
 - (FIRSnapshotMetadata *)metadata {
diff --git a/Firestore/Source/API/FIRQuery.mm b/Firestore/Source/API/FIRQuery.mm
index 45ee482..c277561 100644
--- a/Firestore/Source/API/FIRQuery.mm
+++ b/Firestore/Source/API/FIRQuery.mm
@@ -469,8 +469,7 @@ addSnapshotListenerInternalWithOptions:(FSTListenOptions *)internalOptions
             @"Invalid query. When querying by document ID you must provide "
              "a valid document ID, but it was an empty string.");
       }
-      FSTResourcePath *path = [[FSTResourcePath resourcePathWithCPPResourcePath:self.query.path]
-          pathByAppendingSegment:documentKey];
+      ResourcePath path = self.query.path.Append([documentKey UTF8String]);
       fieldValue = [FSTReferenceValue referenceValue:[FSTDocumentKey keyWithPath:path]
                                           databaseID:self.firestore.databaseID];
     } else if ([value isKindOfClass:[FIRDocumentReference class]]) {
@@ -621,10 +620,8 @@ addSnapshotListenerInternalWithOptions:(FSTListenOptions *)internalOptions
         FSTThrowInvalidUsage(@"InvalidQueryException",
                              @"Invalid query. Document ID '%@' contains a slash.", documentID);
       }
-      FSTDocumentKey *key = [FSTDocumentKey
-          keyWithPath:[FSTResourcePath
-                          resourcePathWithCPPResourcePath:self.query.path.Append(
-                                                              [documentID UTF8String])]];
+      FSTDocumentKey *key =
+          [FSTDocumentKey keyWithPath:self.query.path.Append([documentID UTF8String])];
       [components
           addObject:[FSTReferenceValue referenceValue:key databaseID:self.firestore.databaseID]];
     } else {