1 files changed, 71 insertions, 0 deletions
diff --git a/dom/localstorage/LSWriteOptimizer.cpp b/dom/localstorage/LSWriteOptimizer.cpp
new file mode 100644
index 0000000000..23f88d0c78
--- /dev/null
+++ b/dom/localstorage/LSWriteOptimizer.cpp
@@ -0,0 +1,71 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LSWriteOptimizer.h"
+
+#include <new>
+#include "nsBaseHashtable.h"
+#include "nsTArray.h"
+
+namespace mozilla::dom {
+
+class LSWriteOptimizerBase::WriteInfoComparator {
+ public:
+  bool Equals(const WriteInfo* a, const WriteInfo* b) const {
+    MOZ_ASSERT(a && b);
+    return a->SerialNumber() == b->SerialNumber();
+  }
+
+  bool LessThan(const WriteInfo* a, const WriteInfo* b) const {
+    MOZ_ASSERT(a && b);
+    return a->SerialNumber() < b->SerialNumber();
+  }
+};
+
+void LSWriteOptimizerBase::DeleteItem(const nsAString& aKey, int64_t aDelta) {
+  AssertIsOnOwningThread();
+
+  WriteInfo* existingWriteInfo;
+  if (mWriteInfos.Get(aKey, &existingWriteInfo) &&
+      existingWriteInfo->GetType() == WriteInfo::InsertItem) {
+    mWriteInfos.Remove(aKey);
+  } else {
+    mWriteInfos.Put(aKey, MakeUnique<DeleteItemInfo>(NextSerialNumber(), aKey));
+  }
+
+  mTotalDelta += aDelta;
+}
+
+void LSWriteOptimizerBase::Truncate(int64_t aDelta) {
+  AssertIsOnOwningThread();
+
+  mWriteInfos.Clear();
+
+  if (!mTruncateInfo) {
+    mTruncateInfo = MakeUnique<TruncateInfo>(NextSerialNumber());
+  }
+
+  mTotalDelta += aDelta;
+}
+
+void LSWriteOptimizerBase::GetSortedWriteInfos(
+    nsTArray<NotNull<WriteInfo*>>& aWriteInfos) {
+  AssertIsOnOwningThread();
+
+  if (mTruncateInfo) {
+    aWriteInfos.InsertElementSorted(WrapNotNullUnchecked(mTruncateInfo.get()),
+                                    WriteInfoComparator());
+  }
+
+  for (auto iter = mWriteInfos.ConstIter(); !iter.Done(); iter.Next()) {
+    WriteInfo* writeInfo = iter.UserData();
+
+    aWriteInfos.InsertElementSorted(WrapNotNull(writeInfo),
+                                    WriteInfoComparator());
+  }
+}
+
+}  // namespace mozilla::dom