Port FIRDocumentChange to C++.

Firestore/Example/Tests/API/FIRQuerySnapshotTests.mm

@@ -42,16 +42,6 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-@interface FIRDocumentChange ()
-
-// Expose initializer for testing.
-- (instancetype)initWithType:(FIRDocumentChangeType)type
-                    document:(FIRQueryDocumentSnapshot *)document
-                    oldIndex:(NSUInteger)oldIndex
-                    newIndex:(NSUInteger)newIndex;
-
-@end
-
 @interface FIRQuerySnapshotTests : XCTestCase
 @end
 
@@ -91,56 +81,40 @@ - (void)testIncludeMetadataChanges {
   DocumentSet oldDocuments = FSTTestDocSet(FSTDocumentComparatorByKey, @[ doc1Old, doc2Old ]);
   DocumentSet newDocuments = FSTTestDocSet(FSTDocumentComparatorByKey, @[ doc2New, doc2New ]);
   std::vector<DocumentViewChange> documentChanges{
-      DocumentViewChange{doc1New, DocumentViewChange::Type::kMetadata},
-      DocumentViewChange{doc2New, DocumentViewChange::Type::kModified},
+      DocumentViewChange(doc1New, DocumentViewChange::Type::kMetadata),
+      DocumentViewChange(doc2New, DocumentViewChange::Type::kModified),
   };
 
   Firestore *firestore = FSTTestFirestore().wrapped;
   FSTQuery *query = FSTTestQuery("foo");
-  ViewSnapshot viewSnapshot{query,
-                            newDocuments,
-                            oldDocuments,
-                            std::move(documentChanges),
-                            /*mutated_keys=*/DocumentKeySet{},
+  ViewSnapshot viewSnapshot(query, newDocuments, oldDocuments, std::move(documentChanges),
+                            /*mutated_keys=*/DocumentKeySet(),
                             /*from_cache=*/false,
                             /*sync_state_changed=*/true,
-                            /*excludes_metadata_changes=*/false};
+                            /*excludes_metadata_changes=*/false);
   SnapshotMetadata metadata(/*pending_writes=*/false, /*from_cache=*/false);
   FIRQuerySnapshot *snapshot = [[FIRQuerySnapshot alloc] initWithFirestore:firestore
                                                              originalQuery:query
                                                                   snapshot:std::move(viewSnapshot)
                                                                   metadata:std::move(metadata)];
 
-  FIRQueryDocumentSnapshot *doc1Snap =
-      [[FIRQueryDocumentSnapshot alloc] initWithFirestore:firestore
-                                              documentKey:doc1New.key
-                                                 document:doc1New
-                                                fromCache:false
-                                         hasPendingWrites:false];
-  FIRQueryDocumentSnapshot *doc2Snap =
-      [[FIRQueryDocumentSnapshot alloc] initWithFirestore:firestore
-                                              documentKey:doc2New.key
-                                                 document:doc2New
-                                                fromCache:false
-                                         hasPendingWrites:false];
+  DocumentSnapshot doc1Snap(firestore, doc1New.key, doc1New, SnapshotMetadata());
+  DocumentSnapshot doc2Snap(firestore, doc2New.key, doc2New, SnapshotMetadata());
 
   NSArray<FIRDocumentChange *> *changesWithoutMetadata = @[
-    [[FIRDocumentChange alloc] initWithType:FIRDocumentChangeTypeModified
-                                   document:doc2Snap
-                                   oldIndex:1
-                                   newIndex:1],
+    [[FIRDocumentChange alloc]
+        initWithDocumentChange:DocumentChange(DocumentChange::Type::Modified, doc2Snap,
+                                              /*old_index=*/1, /*new_index=*/1)],
   ];
   XCTAssertEqualObjects(snapshot.documentChanges, changesWithoutMetadata);
 
   NSArray<FIRDocumentChange *> *changesWithMetadata = @[
-    [[FIRDocumentChange alloc] initWithType:FIRDocumentChangeTypeModified
-                                   document:doc1Snap
-                                   oldIndex:0
-                                   newIndex:0],
-    [[FIRDocumentChange alloc] initWithType:FIRDocumentChangeTypeModified
-                                   document:doc2Snap
-                                   oldIndex:1
-                                   newIndex:1],
+    [[FIRDocumentChange alloc]
+        initWithDocumentChange:DocumentChange(DocumentChange::Type::Modified, doc1Snap,
+                                              /*old_index=*/0, /*new_index=*/0)],
+    [[FIRDocumentChange alloc]
+        initWithDocumentChange:DocumentChange(DocumentChange::Type::Modified, doc2Snap,
+                                              /*old_index=*/1, /*new_index=*/1)],
   ];
   XCTAssertEqualObjects([snapshot documentChangesWithIncludeMetadataChanges:YES],
                         changesWithMetadata);

Firestore/Source/API/FIRDocumentChange+Internal.h

@@ -16,21 +16,17 @@
 
 #import "FIRDocumentChange.h"
 
-#include "Firestore/core/src/firebase/firestore/api/firestore.h"
-#include "Firestore/core/src/firebase/firestore/core/view_snapshot.h"
+#import <Foundation/Foundation.h>
 
-@class FIRFirestore;
+#include "Firestore/core/src/firebase/firestore/api/document_change.h"
+
+using firebase::firestore::api::DocumentChange;
 
 NS_ASSUME_NONNULL_BEGIN
 
-/** Internal FIRDocumentChange API we don't want exposed in our public header files. */
-@interface FIRDocumentChange (Internal)
+@interface FIRDocumentChange (/* Init */)
 
-/** Calculates the array of FIRDocumentChange's based on the given FSTViewSnapshot. */
-+ (NSArray<FIRDocumentChange *> *)
-    documentChangesForSnapshot:(const firebase::firestore::core::ViewSnapshot &)snapshot
-        includeMetadataChanges:(bool)includeMetadataChanges
-                     firestore:(firebase::firestore::api::Firestore *)firestore;
+- (instancetype)initWithDocumentChange:(DocumentChange &&)documentChange NS_DESIGNATED_INITIALIZER;
 
 @end
 

Firestore/Source/API/FIRDocumentChange.mm

@@ -14,128 +14,24 @@
  * limitations under the License.
  */
 
-#import "FIRDocumentChange.h"
+#import "Firestore/Source/API/FIRDocumentChange+Internal.h"
 
 #import "Firestore/Source/API/FIRDocumentSnapshot+Internal.h"
-#import "Firestore/Source/API/FIRFirestore+Internal.h"
-#import "Firestore/Source/Core/FSTQuery.h"
-#import "Firestore/Source/Model/FSTDocument.h"
 
-#include "Firestore/core/src/firebase/firestore/core/view_snapshot.h"
-#include "Firestore/core/src/firebase/firestore/model/document_set.h"
+#include "Firestore/core/src/firebase/firestore/api/document_change.h"
 #include "Firestore/core/src/firebase/firestore/util/hard_assert.h"
 
-using firebase::firestore::api::Firestore;
-using firebase::firestore::core::DocumentViewChange;
-using firebase::firestore::core::ViewSnapshot;
-using firebase::firestore::model::DocumentSet;
+using firebase::firestore::api::DocumentChange;
 
 NS_ASSUME_NONNULL_BEGIN
 
-@interface FIRDocumentChange ()
-
-- (instancetype)initWithType:(FIRDocumentChangeType)type
-                    document:(FIRDocumentSnapshot *)document
-                    oldIndex:(NSUInteger)oldIndex
-                    newIndex:(NSUInteger)newIndex NS_DESIGNATED_INITIALIZER;
-
-@end
-
-@implementation FIRDocumentChange (Internal)
-
-+ (FIRDocumentChangeType)documentChangeTypeForChange:(const DocumentViewChange &)change {
-  switch (change.type()) {
-    case DocumentViewChange::Type::kAdded:
-      return FIRDocumentChangeTypeAdded;
-    case DocumentViewChange::Type::kModified:
-    case DocumentViewChange::Type::kMetadata:
-      return FIRDocumentChangeTypeModified;
-    case DocumentViewChange::Type::kRemoved:
-      return FIRDocumentChangeTypeRemoved;
-  }
-
-  HARD_FAIL("Unknown DocumentViewChange::Type: %s", change.type());
+@implementation FIRDocumentChange {
+  DocumentChange _documentChange;
 }
 
-+ (NSArray<FIRDocumentChange *> *)documentChangesForSnapshot:(const ViewSnapshot &)snapshot
-                                      includeMetadataChanges:(bool)includeMetadataChanges
-                                                   firestore:(Firestore *)firestore {
-  if (snapshot.old_documents().empty()) {
-    // Special case the first snapshot because index calculation is easy and fast. Also all changes
-    // on the first snapshot are adds so there are also no metadata-only changes to filter out.
-    FSTDocument *_Nullable lastDocument = nil;
-    NSUInteger index = 0;
-    NSMutableArray<FIRDocumentChange *> *changes = [NSMutableArray array];
-    for (const DocumentViewChange &change : snapshot.document_changes()) {
-      FIRQueryDocumentSnapshot *document = [[FIRQueryDocumentSnapshot alloc]
-          initWithFirestore:firestore
-                documentKey:change.document().key
-                   document:change.document()
-                  fromCache:snapshot.from_cache()
-           hasPendingWrites:snapshot.mutated_keys().contains(change.document().key)];
-      HARD_ASSERT(change.type() == DocumentViewChange::Type::kAdded,
-                  "Invalid event type for first snapshot");
-      HARD_ASSERT(!lastDocument || snapshot.query().comparator(lastDocument, change.document()) ==
-                                       NSOrderedAscending,
-                  "Got added events in wrong order");
-      [changes addObject:[[FIRDocumentChange alloc] initWithType:FIRDocumentChangeTypeAdded
-                                                        document:document
-                                                        oldIndex:NSNotFound
-                                                        newIndex:index++]];
-    }
-    return changes;
-  } else {
-    // A DocumentSet that is updated incrementally as changes are applied to use to lookup the index
-    // of a document.
-    DocumentSet indexTracker = snapshot.old_documents();
-    NSMutableArray<FIRDocumentChange *> *changes = [NSMutableArray array];
-    for (const DocumentViewChange &change : snapshot.document_changes()) {
-      if (!includeMetadataChanges && change.type() == DocumentViewChange::Type::kMetadata) {
-        continue;
-      }
-
-      FIRQueryDocumentSnapshot *document = [[FIRQueryDocumentSnapshot alloc]
-          initWithFirestore:firestore
-                documentKey:change.document().key
-                   document:change.document()
-                  fromCache:snapshot.from_cache()
-           hasPendingWrites:snapshot.mutated_keys().contains(change.document().key)];
-
-      size_t oldIndex = DocumentSet::npos;
-      size_t newIndex = DocumentSet::npos;
-      if (change.type() != DocumentViewChange::Type::kAdded) {
-        oldIndex = indexTracker.IndexOf(change.document().key);
-        HARD_ASSERT(oldIndex != DocumentSet::npos, "Index for document not found");
-        indexTracker = indexTracker.erase(change.document().key);
-      }
-      if (change.type() != DocumentViewChange::Type::kRemoved) {
-        indexTracker = indexTracker.insert(change.document());
-        newIndex = indexTracker.IndexOf(change.document().key);
-      }
-      [FIRDocumentChange documentChangeTypeForChange:change];
-      FIRDocumentChangeType type = [FIRDocumentChange documentChangeTypeForChange:change];
-      [changes addObject:[[FIRDocumentChange alloc] initWithType:type
-                                                        document:document
-                                                        oldIndex:oldIndex
-                                                        newIndex:newIndex]];
-    }
-    return changes;
-  }
-}
-
-@end
-
-@implementation FIRDocumentChange
-
-- (instancetype)initWithType:(FIRDocumentChangeType)type
-                    document:(FIRQueryDocumentSnapshot *)document
-                    oldIndex:(NSUInteger)oldIndex
-                    newIndex:(NSUInteger)newIndex {
+- (instancetype)initWithDocumentChange:(DocumentChange &&)documentChange {
   if (self = [super init]) {
-    _type = type;
-    _document = document;
-    _oldIndex = oldIndex;
-    _newIndex = newIndex;
+    _documentChange = std::move(documentChange);
   }
   return self;
 }
@@ -145,16 +41,36 @@ - (BOOL)isEqual:(nullable id)other {
   if (![other isKindOfClass:[FIRDocumentChange class]]) return NO;
 
   FIRDocumentChange *change = (FIRDocumentChange *)other;
-  return self.type == change.type && [self.document isEqual:change.document] &&
-         self.oldIndex == change.oldIndex && self.newIndex == change.newIndex;
+  return _documentChange == change->_documentChange;
 }
 
 - (NSUInteger)hash {
-  NSUInteger result = (NSUInteger)self.type;
-  result = result * 31u + [self.document hash];
-  result = result * 31u + (NSUInteger)self.oldIndex;
-  result = result * 31u + (NSUInteger)self.newIndex;
-  return result;
+  return _documentChange.Hash();
+}
+
+- (FIRDocumentChangeType)type {
+  switch (_documentChange.type()) {
+    case DocumentChange::Type::Added:
+      return FIRDocumentChangeTypeAdded;
+    case DocumentChange::Type::Modified:
+      return FIRDocumentChangeTypeModified;
+    case DocumentChange::Type::Removed:
+      return FIRDocumentChangeTypeRemoved;
+  }
+
+  HARD_FAIL("Unknown DocumentChange::Type: %s", _documentChange.type());
+}
+
+- (FIRQueryDocumentSnapshot *)document {
+  return [[FIRQueryDocumentSnapshot alloc] initWithSnapshot:_documentChange.document()];
+}
+
+- (NSUInteger)oldIndex {
+  return _documentChange.old_index();
+}
+
+- (NSUInteger)newIndex {
+  return _documentChange.new_index();
 }
 
 @end

Firestore/Source/API/FIRQuerySnapshot.mm

@@ -123,15 +123,15 @@ - (NSInteger)count {
 
 - (NSArray<FIRDocumentChange *> *)documentChangesWithIncludeMetadataChanges:
     (BOOL)includeMetadataChanges {
-  if (includeMetadataChanges && _snapshot->view_snapshot().excludes_metadata_changes()) {
-    ThrowInvalidArgument("To include metadata changes with your document changes, you must call "
-                         "addSnapshotListener(includeMetadataChanges: true).");
-  }
-
   if (!_documentChanges || _documentChangesIncludeMetadataChanges != includeMetadataChanges) {
-    _documentChanges = [FIRDocumentChange documentChangesForSnapshot:_snapshot->view_snapshot()
-                                              includeMetadataChanges:includeMetadataChanges
-                                                           firestore:_snapshot->firestore()];
+    NSMutableArray *documentChanges = [NSMutableArray array];
+    _snapshot->ForEachChange(
+        static_cast<bool>(includeMetadataChanges), [&documentChanges](DocumentChange change) {
+          [documentChanges
+              addObject:[[FIRDocumentChange alloc] initWithDocumentChange:std::move(change)]];
+        });
+
+    _documentChanges = documentChanges;
     _documentChangesIncludeMetadataChanges = includeMetadataChanges;
   }
   return _documentChanges;