1 files changed, 52 insertions, 0 deletions
diff --git a/Firestore/Source/Local/FSTWriteGroupTracker.mm b/Firestore/Source/Local/FSTWriteGroupTracker.mm
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+++ b/Firestore/Source/Local/FSTWriteGroupTracker.mm
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2017 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "Firestore/Source/Local/FSTWriteGroupTracker.h"
+
+#import "Firestore/Source/Local/FSTWriteGroup.h"
+#import "Firestore/Source/Util/FSTAssert.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface FSTWriteGroupTracker ()
+@property(nonatomic, strong, nullable) FSTWriteGroup *activeGroup;
+@end
+
+@implementation FSTWriteGroupTracker
+
++ (instancetype)tracker {
+  return [[FSTWriteGroupTracker alloc] init];
+}
+
+- (FSTWriteGroup *)startGroupWithAction:(NSString *)action {
+  // NOTE: We can relax this to allow nesting if/when we find we need it.
+  FSTAssert(!self.activeGroup,
+            @"Attempt to create write group (%@) while existing write group (%@) still active.",
+            action, self.activeGroup.action);
+  self.activeGroup = [FSTWriteGroup groupWithAction:action];
+  return self.activeGroup;
+}
+
+- (void)endGroup:(FSTWriteGroup *)group {
+  FSTAssert(self.activeGroup == group,
+            @"Attempted to end write group (%@) which is different from active group (%@)",
+            group.action, self.activeGroup.action);
+  self.activeGroup = nil;
+}
+
+@end
+
+NS_ASSUME_NONNULL_END