Bug 1484113 - part 1: Create HTMLEditor::GetFirstTableRowElement() for internal use of nsITableEditor::GetFirstRow() r=m_kato

nsITableEditor::GetFirstRow() is an XPCOM method, so, for internal use,
we should create non-virtual method, that is GetFirstTableRowElement().

This patch makes it never return NS_SUCCESS_EDITOR_ELEMENT_NOT_FOUND since
nobody refers it and it's detectable.  If the method returns nullptr without
error, it's the case of NS_SUCCESS_EDITOR_ELEMENT_NOT_FOUND.

Additionally, this patch changes the return type of GetFirstRow() from
Node to Element since it always return an Element node if not null.

Differential Revision: https://phabricator.services.mozilla.com/D3780

--HG--
extra : moz-landing-system : lando

editor/libeditor/HTMLEditor.cpp

@@ -2561,7 +2561,7 @@ HTMLEditor::Align(const nsAString& aAlignType)
 
 Element*
 HTMLEditor::GetElementOrParentByTagName(const nsAtom& aTagName,
-                                        nsINode* aNode)
+                                        nsINode* aNode) const
 {
   MOZ_ASSERT(&aTagName != nsGkAtoms::_empty);
 
@@ -2577,7 +2577,7 @@ HTMLEditor::GetElementOrParentByTagName(const nsAtom& aTagName,
 
 Element*
 HTMLEditor::GetElementOrParentByTagNameAtSelection(Selection& aSelection,
-                                                   const nsAtom& aTagName)
+                                                   const nsAtom& aTagName) const
 {
   MOZ_ASSERT(&aTagName != nsGkAtoms::_empty);
 
@@ -2605,7 +2605,7 @@ HTMLEditor::GetElementOrParentByTagNameAtSelection(Selection& aSelection,
 
 Element*
 HTMLEditor::GetElementOrParentByTagNameInternal(const nsAtom& aTagName,
-                                                nsINode& aNode)
+                                                nsINode& aNode) const
 {
   MOZ_ASSERT(&aTagName != nsGkAtoms::_empty);
 

editor/libeditor/HTMLEditor.h

@@ -402,7 +402,7 @@ public:
    *                        an Element.  Otherwise, nullptr.
    */
   Element*
-  GetElementOrParentByTagName(const nsAtom& aTagName, nsINode* aNode);
+  GetElementOrParentByTagName(const nsAtom& aTagName, nsINode* aNode) const;
 
   /**
     * Get an active editor's editing host in DOM window.  If this editor isn't
@@ -912,7 +912,7 @@ protected: // Shouldn't be used by friend classes
    */
   Element*
   GetElementOrParentByTagNameAtSelection(Selection& aSelection,
-                                         const nsAtom& aTagName);
+                                         const nsAtom& aTagName) const;
 
   /**
    * GetElementOrParentByTagNameInternal() looks for an element node whose
@@ -933,7 +933,7 @@ protected: // Shouldn't be used by friend classes
    */
   Element*
   GetElementOrParentByTagNameInternal(const nsAtom& aTagName,
-                                      nsINode& aNode);
+                                      nsINode& aNode) const;
 
   /**
    * GetSelectedElement() returns an element node which is in first range of
@@ -972,6 +972,26 @@ protected: // Shouldn't be used by friend classes
                      const nsAtom* aTagName,
                      ErrorResult& aRv);
 
+  /**
+   * GetFirstTableRowElement() returns the first <tr> element in the most
+   * nearest ancestor of aTableOrElementInTable or itself.
+   *
+   * @param aTableOrElementInTable      <table> element or another element.
+   *                                    If this is a <table> element, returns
+   *                                    first <tr> element in it.  Otherwise,
+   *                                    returns first <tr> element in nearest
+   *                                    ancestor <table> element.
+   * @param aRv                         Returns an error code.  When
+   *                                    aTableOrElementInTable is neither
+   *                                    <table> nor in a <table> element,
+   *                                    returns NS_ERROR_FAILURE.
+   *                                    However, if <table> does not have
+   *                                    <tr> element, returns NS_OK.
+   */
+  Element*
+  GetFirstTableRowElement(Element& aTableOrElementInTable,
+                          ErrorResult& aRv) const;
+
   /**
    * PasteInternal() pasts text with replacing selected content.
    * This tries to dispatch ePaste event first.  If its defaultPrevent() is

editor/libeditor/HTMLTableEditor.cpp

@@ -221,52 +221,60 @@ HTMLEditor::InsertTableCell(int32_t aNumber,
 }
 
 NS_IMETHODIMP
-HTMLEditor::GetFirstRow(Element* aTableElement,
-                        nsINode** aRowNode)
+HTMLEditor::GetFirstRow(Element* aTableOrElementInTable,
+                        Element** aFirstRowElement)
 {
-  if (NS_WARN_IF(!aTableElement) || NS_WARN_IF(!aRowNode)) {
+  if (NS_WARN_IF(!aTableOrElementInTable) || NS_WARN_IF(!aFirstRowElement)) {
     return NS_ERROR_INVALID_ARG;
   }
-
-  *aRowNode = nullptr;
-
-  Element* tableElement =
-    GetElementOrParentByTagNameInternal(*nsGkAtoms::table, *aTableElement);
-  if (NS_WARN_IF(!tableElement)) {
-    return NS_ERROR_FAILURE;
+  ErrorResult error;
+  RefPtr<Element> firstRowElement =
+    GetFirstTableRowElement(*aTableOrElementInTable, error);
+  if (NS_WARN_IF(error.Failed())) {
+    return error.StealNSResult();
   }
-
-  nsCOMPtr<nsIContent> tableChild = tableElement->GetFirstChild();
-  while (tableChild) {
-    if (tableChild->IsHTMLElement(nsGkAtoms::tr)) {
-      // Found a row directly under <table>
-      tableChild.forget(aRowNode);
+  firstRowElement.forget(aFirstRowElement);
   return NS_OK;
 }
-    // Look for row in one of the row container elements
+
+Element*
+HTMLEditor::GetFirstTableRowElement(Element& aTableOrElementInTable,
+                                    ErrorResult& aRv) const
+{
+  MOZ_ASSERT(!aRv.Failed());
+
+  Element* tableElement =
+    GetElementOrParentByTagNameInternal(*nsGkAtoms::table,
+                                        aTableOrElementInTable);
+  // If the element is not in <table>, return error.
+  if (NS_WARN_IF(!tableElement)) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return nullptr;
+  }
+
+  for (nsIContent* tableChild = tableElement->GetFirstChild();
+       tableChild;
+       tableChild = tableChild->GetNextSibling()) {
+    if (tableChild->IsHTMLElement(nsGkAtoms::tr)) {
+      // Found a row directly under <table>
+      return tableChild->AsElement();
+    }
+    // <table> can have table section elements like <tbody>.  <tr> elements
+    // may be children of them.
     if (tableChild->IsAnyOfHTMLElements(nsGkAtoms::tbody,
                                         nsGkAtoms::thead,
                                         nsGkAtoms::tfoot)) {
-      nsCOMPtr<nsIContent> rowNode = tableChild->GetFirstChild();
-
-      // We can encounter textnodes here -- must find a row
-      while (rowNode && !HTMLEditUtils::IsTableRow(rowNode)) {
-        rowNode = rowNode->GetNextSibling();
-      }
-
-      if (rowNode) {
-        rowNode.forget(aRowNode);
-        return NS_OK;
+      for (nsIContent* tableSectionChild = tableChild->GetFirstChild();
+           tableSectionChild;
+           tableSectionChild = tableSectionChild->GetNextSibling()) {
+        if (tableSectionChild->IsHTMLElement(nsGkAtoms::tr)) {
+          return tableSectionChild->AsElement();
         }
       }
-    // Here if table child was a CAPTION or COLGROUP
-    //  or child of a row parent wasn't a row (bad HTML?),
-    //  or first child was a textnode
-    // Look in next table child
-    tableChild = tableChild->GetNextSibling();
     }
-  // If here, row was not found
-  return NS_SUCCESS_EDITOR_ELEMENT_NOT_FOUND;
+  }
+  // Don't return error when there is no <tr> element in the <table>.
+  return nullptr;
 }
 
 NS_IMETHODIMP
@@ -442,9 +450,10 @@ HTMLEditor::InsertTableColumn(int32_t aNumber,
     } else {
       // Get current row and append new cells after last cell in row
       if (!rowIndex) {
-        rv = GetFirstRow(table, getter_AddRefs(rowNode));
-        if (NS_WARN_IF(NS_FAILED(rv))) {
-          return rv;
+        ErrorResult error;
+        rowNode = GetFirstTableRowElement(*table, error);
+        if (NS_WARN_IF(error.Failed())) {
+          return error.StealNSResult();
         }
       } else {
         nsCOMPtr<nsINode> nextRow;

editor/nsITableEditor.idl

@@ -203,14 +203,25 @@ interface nsITableEditor : nsISupports
                      out long  aActualRowSpan, out long  aActualColSpan,
                      out boolean aIsSelected);
 
-  /** Get the first row element in a table
+  /**
+   * getFirstRow() returns first <tr> element in a <table> element.
    *
-    * @return            The row at the requested index
-    *                    Returns null if there are no rows in table
-    * (in C++ returns: NS_EDITOR_ELEMENT_NOT_FOUND if an element is not found
-    *  passes NS_SUCCEEDED macro)
+   * @param aTableOrElementInTable  If a <table> element, returns its first
+   *                                <tr> element.
+   *                                If another element, looks for nearest
+   *                                ancestor <table> element first.  Then,
+   *                                return its first <tr> element.
+   * @return                        <tr> element in the <table> element.
+   *                                If <table> element is not found, this
+   *                                throws an exception.
+   *                                If there is a <table> element but it
+   *                                does not have <tr> elements, returns
+   *                                null without throwing exception.
+   *                                Note that this may return anonymous <tr>
+   *                                element if <table> has one or more cells
+   *                                but <tr> element is not in the source.
    */
-  Node getFirstRow(in Element aTableElement);
+  Element getFirstRow(in Element aTableElement);
 
   /** Get the next row element starting the search from aTableElement
     *