1 files changed, 257 insertions, 0 deletions
diff --git a/editor/libeditor/PlaceholderTransaction.cpp b/editor/libeditor/PlaceholderTransaction.cpp
new file mode 100644
index 0000000000..1f616dee98
--- /dev/null
+++ b/editor/libeditor/PlaceholderTransaction.cpp
@@ -0,0 +1,257 @@
+/* -*- 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/. */
+
+#include "PlaceholderTransaction.h"
+
+#include <utility>
+
+#include "CompositionTransaction.h"
+#include "mozilla/EditorBase.h"
+#include "mozilla/dom/Selection.h"
+#include "nsGkAtoms.h"
+#include "nsQueryObject.h"
+
+namespace mozilla {
+
+using namespace dom;
+
+PlaceholderTransaction::PlaceholderTransaction(
+    EditorBase& aEditorBase, nsStaticAtom& aName,
+    Maybe<SelectionState>&& aSelState)
+    : mEditorBase(&aEditorBase),
+      mCompositionTransaction(nullptr),
+      mStartSel(*std::move(aSelState)),
+      mAbsorb(true),
+      mCommitted(false) {
+  mName = &aName;
+}
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(PlaceholderTransaction)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(PlaceholderTransaction,
+                                                EditAggregateTransaction)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mEditorBase);
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mStartSel);
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mEndSel);
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(PlaceholderTransaction,
+                                                  EditAggregateTransaction)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEditorBase);
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mStartSel);
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEndSel);
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(PlaceholderTransaction)
+NS_INTERFACE_MAP_END_INHERITING(EditAggregateTransaction)
+
+NS_IMPL_ADDREF_INHERITED(PlaceholderTransaction, EditAggregateTransaction)
+NS_IMPL_RELEASE_INHERITED(PlaceholderTransaction, EditAggregateTransaction)
+
+NS_IMETHODIMP PlaceholderTransaction::DoTransaction() { return NS_OK; }
+
+NS_IMETHODIMP PlaceholderTransaction::UndoTransaction() {
+  if (NS_WARN_IF(!mEditorBase)) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  // Undo transactions.
+  nsresult rv = EditAggregateTransaction::UndoTransaction();
+  if (NS_FAILED(rv)) {
+    NS_WARNING("EditAggregateTransaction::UndoTransaction() failed");
+    return rv;
+  }
+
+  // now restore selection
+  RefPtr<Selection> selection = mEditorBase->GetSelection();
+  if (NS_WARN_IF(!selection)) {
+    return NS_ERROR_FAILURE;
+  }
+  rv = mStartSel.RestoreSelection(*selection);
+  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
+                       "SelectionState::RestoreSelection() failed");
+  return rv;
+}
+
+NS_IMETHODIMP PlaceholderTransaction::RedoTransaction() {
+  if (NS_WARN_IF(!mEditorBase)) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  // Redo transactions.
+  nsresult rv = EditAggregateTransaction::RedoTransaction();
+  if (NS_FAILED(rv)) {
+    NS_WARNING("EditAggregateTransaction::RedoTransaction() failed");
+    return rv;
+  }
+
+  // now restore selection
+  RefPtr<Selection> selection = mEditorBase->GetSelection();
+  if (NS_WARN_IF(!selection)) {
+    return NS_ERROR_FAILURE;
+  }
+  rv = mEndSel.RestoreSelection(*selection);
+  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
+                       "SelectionState::RestoreSelection() failed");
+  return rv;
+}
+
+NS_IMETHODIMP PlaceholderTransaction::Merge(nsITransaction* aOtherTransaction,
+                                            bool* aDidMerge) {
+  if (NS_WARN_IF(!aDidMerge) || NS_WARN_IF(!aOtherTransaction)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  // set out param default value
+  *aDidMerge = false;
+
+  if (mForwardingTransaction) {
+    MOZ_ASSERT_UNREACHABLE(
+        "tried to merge into a placeholder that was in "
+        "forwarding mode!");
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<EditTransactionBase> otherTransactionBase =
+      aOtherTransaction->GetAsEditTransactionBase();
+  if (!otherTransactionBase) {
+    return NS_OK;
+  }
+
+  // We are absorbing all transactions if mAbsorb is lit.
+  if (mAbsorb) {
+    if (CompositionTransaction* otherCompositionTransaction =
+            otherTransactionBase->GetAsCompositionTransaction()) {
+      // special handling for CompositionTransaction's: they need to merge with
+      // any previous CompositionTransaction in this placeholder, if possible.
+      if (!mCompositionTransaction) {
+        // this is the first IME txn in the placeholder
+        mCompositionTransaction = otherCompositionTransaction;
+        DebugOnly<nsresult> rvIgnored =
+            AppendChild(otherCompositionTransaction);
+        NS_WARNING_ASSERTION(
+            NS_SUCCEEDED(rvIgnored),
+            "EditAggregateTransaction::AppendChild() failed, but ignored");
+      } else {
+        bool didMerge;
+        mCompositionTransaction->Merge(otherCompositionTransaction, &didMerge);
+        if (!didMerge) {
+          // it wouldn't merge.  Earlier IME txn is already committed and will
+          // not absorb further IME txns.  So just stack this one after it
+          // and remember it as a candidate for further merges.
+          mCompositionTransaction = otherCompositionTransaction;
+          DebugOnly<nsresult> rvIgnored =
+              AppendChild(otherCompositionTransaction);
+          NS_WARNING_ASSERTION(
+              NS_SUCCEEDED(rvIgnored),
+              "EditAggregateTransaction::AppendChild() failed, but ignored");
+        }
+      }
+    } else {
+      PlaceholderTransaction* otherPlaceholderTransaction =
+          otherTransactionBase->GetAsPlaceholderTransaction();
+      if (!otherPlaceholderTransaction) {
+        // See bug 171243: just drop incoming placeholders on the floor.
+        // Their children will be swallowed by this preexisting one.
+        DebugOnly<nsresult> rvIgnored = AppendChild(otherTransactionBase);
+        NS_WARNING_ASSERTION(
+            NS_SUCCEEDED(rvIgnored),
+            "EditAggregateTransaction::AppendChild() failed, but ignored");
+      }
+    }
+    *aDidMerge = true;
+    //  RememberEndingSelection();
+    //  efficiency hack: no need to remember selection here, as we haven't yet
+    //  finished the initial batch and we know we will be told when the batch
+    //  ends. we can remeber the selection then.
+    return NS_OK;
+  }
+
+  // merge typing or IME or deletion transactions if the selection matches
+  if (mCommitted ||
+      (mName != nsGkAtoms::TypingTxnName && mName != nsGkAtoms::IMETxnName &&
+       mName != nsGkAtoms::DeleteTxnName)) {
+    return NS_OK;
+  }
+
+  PlaceholderTransaction* otherPlaceholderTransaction =
+      otherTransactionBase->GetAsPlaceholderTransaction();
+  if (!otherPlaceholderTransaction) {
+    return NS_OK;
+  }
+
+  RefPtr<nsAtom> otherTransactionName;
+  DebugOnly<nsresult> rvIgnored = otherPlaceholderTransaction->GetName(
+      getter_AddRefs(otherTransactionName));
+  NS_WARNING_ASSERTION(NS_SUCCEEDED(rvIgnored),
+                       "PlaceholderTransaction::GetName() failed, but ignored");
+  if (!otherTransactionName || otherTransactionName == nsGkAtoms::_empty ||
+      otherTransactionName != mName) {
+    return NS_OK;
+  }
+  // check if start selection of next placeholder matches
+  // end selection of this placeholder
+  if (!otherPlaceholderTransaction->StartSelectionEquals(mEndSel)) {
+    return NS_OK;
+  }
+  mAbsorb = true;  // we need to start absorbing again
+  otherPlaceholderTransaction->ForwardEndBatchTo(*this);
+  // AppendChild(editTransactionBase);
+  // see bug 171243: we don't need to merge placeholders
+  // into placeholders.  We just reactivate merging in the
+  // pre-existing placeholder and drop the new one on the floor.  The
+  // EndPlaceHolderBatch() call on the new placeholder will be
+  // forwarded to this older one.
+  rvIgnored = RememberEndingSelection();
+  NS_WARNING_ASSERTION(
+      NS_SUCCEEDED(rvIgnored),
+      "PlaceholderTransaction::RememberEndingSelection() failed, but "
+      "ignored");
+  *aDidMerge = true;
+  return NS_OK;
+}
+
+bool PlaceholderTransaction::StartSelectionEquals(
+    SelectionState& aSelectionState) {
+  // determine if starting selection matches the given selection state.
+  // note that we only care about collapsed selections.
+  return mStartSel.IsCollapsed() && aSelectionState.IsCollapsed() &&
+         mStartSel.Equals(aSelectionState);
+}
+
+nsresult PlaceholderTransaction::EndPlaceHolderBatch() {
+  mAbsorb = false;
+
+  if (mForwardingTransaction) {
+    if (mForwardingTransaction) {
+      DebugOnly<nsresult> rvIgnored =
+          mForwardingTransaction->EndPlaceHolderBatch();
+      NS_WARNING_ASSERTION(
+          NS_SUCCEEDED(rvIgnored),
+          "PlaceholderTransaction::EndPlaceHolderBatch() failed, but ignored");
+    }
+  }
+  // remember our selection state.
+  nsresult rv = RememberEndingSelection();
+  NS_WARNING_ASSERTION(
+      NS_SUCCEEDED(rv),
+      "PlaceholderTransaction::RememberEndingSelection() failed");
+  return rv;
+}
+
+nsresult PlaceholderTransaction::RememberEndingSelection() {
+  if (NS_WARN_IF(!mEditorBase)) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  RefPtr<Selection> selection = mEditorBase->GetSelection();
+  if (NS_WARN_IF(!selection)) {
+    return NS_ERROR_FAILURE;
+  }
+  mEndSel.SaveSelection(*selection);
+  return NS_OK;
+}
+
+}  // namespace mozilla