1 files changed, 108 insertions, 0 deletions
diff --git a/layout/base/nsLayoutHistoryState.cpp b/layout/base/nsLayoutHistoryState.cpp
new file mode 100644
index 000000000..066eeb058
--- /dev/null
+++ b/layout/base/nsLayoutHistoryState.cpp
@@ -0,0 +1,108 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+/*
+ * container for information saved in session history when the document
+ * is not
+ */
+
+#include "nsILayoutHistoryState.h"
+#include "nsWeakReference.h"
+#include "nsClassHashtable.h"
+#include "nsPresState.h"
+#include "mozilla/Attributes.h"
+
+class nsLayoutHistoryState final : public nsILayoutHistoryState,
+                                   public nsSupportsWeakReference
+{
+public:
+  nsLayoutHistoryState()
+    : mScrollPositionOnly(false)
+  {
+  }
+
+  NS_DECL_ISUPPORTS
+
+  // nsILayoutHistoryState
+  virtual void
+  AddState(const nsCString& aKey, nsPresState* aState) override;
+  virtual nsPresState*
+  GetState(const nsCString& aKey) override;
+  virtual void
+  RemoveState(const nsCString& aKey) override;
+  virtual bool
+  HasStates() const override;
+  virtual void
+  SetScrollPositionOnly(const bool aFlag) override;
+  virtual void
+  ResetScrollState() override;
+
+private:
+  ~nsLayoutHistoryState() {}
+  bool mScrollPositionOnly;
+
+  nsClassHashtable<nsCStringHashKey,nsPresState> mStates;
+};
+
+
+already_AddRefed<nsILayoutHistoryState>
+NS_NewLayoutHistoryState()
+{
+  RefPtr<nsLayoutHistoryState> state = new nsLayoutHistoryState();
+  return state.forget();
+}
+
+NS_IMPL_ISUPPORTS(nsLayoutHistoryState,
+                  nsILayoutHistoryState,
+                  nsISupportsWeakReference)
+
+void
+nsLayoutHistoryState::AddState(const nsCString& aStateKey, nsPresState* aState)
+{
+  mStates.Put(aStateKey, aState);
+}
+
+nsPresState*
+nsLayoutHistoryState::GetState(const nsCString& aKey)
+{
+  nsPresState* state = nullptr;
+  bool entryExists = mStates.Get(aKey, &state);
+
+  if (entryExists && mScrollPositionOnly) {
+    // Ensure any state that shouldn't be restored is removed
+    state->ClearNonScrollState();
+  }
+
+  return state;
+}
+
+void
+nsLayoutHistoryState::RemoveState(const nsCString& aKey)
+{
+  mStates.Remove(aKey);
+}
+
+bool
+nsLayoutHistoryState::HasStates() const
+{
+  return mStates.Count() != 0;
+}
+
+void
+nsLayoutHistoryState::SetScrollPositionOnly(const bool aFlag)
+{
+  mScrollPositionOnly = aFlag;
+}
+
+void
+nsLayoutHistoryState::ResetScrollState()
+{
+  for (auto iter = mStates.Iter(); !iter.Done(); iter.Next()) {
+    nsPresState* state = iter.UserData();
+    if (state) {
+      state->SetScrollState(nsPoint(0, 0));
+    }
+  }
+}