fix(cloud_firestore): Fix crashes on iOS/macOS (#11501)

Co-authored-by: russellwheatley <[email protected]>

Author: 2 people

packages/cloud_firestore/cloud_firestore/ios/Classes/FLTFirebaseFirestorePlugin.m

@@ -60,7 +60,7 @@ - (NSString *)registerEventChannelWithPrefix:(NSString *)prefix
                                streamHandler:(NSObject<FlutterStreamHandler> *)handler;
 @end
 
-static NSMutableDictionary<NSNumber *, NSString *> *_serverTimestampMap;
+static NSCache<NSNumber *, NSString *> *_serverTimestampMap;
 
 @implementation FLTFirebaseFirestorePlugin {
   NSMutableDictionary<NSString *, FlutterEventChannel *> *_eventChannels;
@@ -72,9 +72,10 @@ @implementation FLTFirebaseFirestorePlugin {
 FlutterStandardMethodCodec *_codec;
 
 + (NSMutableDictionary<NSNumber *, NSString *> *)serverTimestampMap {
-  if (_serverTimestampMap == nil) {
-    _serverTimestampMap = [NSMutableDictionary<NSNumber *, NSString *> dictionary];
-  }
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    _serverTimestampMap = [NSCache<NSNumber *, NSString *> new];
+  });
   return _serverTimestampMap;
 }
 
@@ -107,7 +108,6 @@ - (instancetype)init:(NSObject<FlutterBinaryMessenger> *)messenger {
     _eventChannels = [NSMutableDictionary dictionary];
     _streamHandlers = [NSMutableDictionary dictionary];
     _transactionHandlers = [NSMutableDictionary dictionary];
-    _serverTimestampMap = [NSMutableDictionary dictionary];
   }
   return self;
 }
@@ -470,7 +470,8 @@ - (void)documentGet:(id)arguments withMethodCallResult:(FLTFirebaseMethodCallRes
     if (error != nil) {
       result.error(nil, nil, nil, error);
     } else {
-      [_serverTimestampMap setObject:serverTimestampBehaviorString forKey:@([snapshot hash])];
+      [FLTFirebaseFirestorePlugin.serverTimestampMap setObject:serverTimestampBehaviorString
+                                                        forKey:@([snapshot hash])];
       result.success(snapshot);
     }
   };

packages/cloud_firestore/cloud_firestore/ios/Classes/FLTFirebaseFirestoreWriter.m

@@ -163,14 +163,12 @@ - (NSDictionary *)FIRDocumentSnapshot:(FIRDocumentSnapshot *)documentSnapshot {
 
   NSNumber *documentSnapshotHash = @([documentSnapshot hash]);
   NSString *timestampBehaviorString =
-      FLTFirebaseFirestorePlugin.serverTimestampMap[documentSnapshotHash];
+      [FLTFirebaseFirestorePlugin.serverTimestampMap objectForKey:documentSnapshotHash];
 
   FIRServerTimestampBehavior serverTimestampBehavior =
       [self toServerTimestampBehavior:timestampBehaviorString];
 
-  if (FLTFirebaseFirestorePlugin.serverTimestampMap[documentSnapshotHash] != nil) {
-    [FLTFirebaseFirestorePlugin.serverTimestampMap removeObjectForKey:documentSnapshotHash];
-  }
+  [FLTFirebaseFirestorePlugin.serverTimestampMap removeObjectForKey:documentSnapshotHash];
 
   return @{
     @"path" : documentSnapshot.reference.path,
@@ -215,14 +213,12 @@ - (NSDictionary *)FIRQuerySnapshot:(FIRQuerySnapshot *)querySnapshot {
   NSMutableArray *documents = [NSMutableArray array];
   NSMutableArray *metadatas = [NSMutableArray array];
   NSString *timestampBehaviorString =
-      FLTFirebaseFirestorePlugin.serverTimestampMap[querySnapshotHash];
+      [FLTFirebaseFirestorePlugin.serverTimestampMap objectForKey:querySnapshotHash];
 
   FIRServerTimestampBehavior serverTimestampBehavior =
       [self toServerTimestampBehavior:timestampBehaviorString];
 
-  if (FLTFirebaseFirestorePlugin.serverTimestampMap[querySnapshotHash] != nil) {
-    [FLTFirebaseFirestorePlugin.serverTimestampMap removeObjectForKey:querySnapshotHash];
-  }
+  [FLTFirebaseFirestorePlugin.serverTimestampMap removeObjectForKey:querySnapshotHash];
 
   for (FIRDocumentSnapshot *document in querySnapshot.documents) {
     [paths addObject:document.reference.path];

packages/cloud_firestore/cloud_firestore/ios/Classes/Public/FLTFirebaseFirestorePlugin.h

@@ -13,5 +13,5 @@
 #import <firebase_core/FLTFirebasePlugin.h>
 
 @interface FLTFirebaseFirestorePlugin : FLTFirebasePlugin <FlutterPlugin, FLTFirebasePlugin>
-+ (NSMutableDictionary<NSNumber *, NSString *> *)serverTimestampMap;
++ (NSCache<NSNumber *, NSString *> *)serverTimestampMap;
 @end