Cleanup CJX_Node::GetAttribute

This CL renames GetAttribute to TryAttribute and changes to return a
pdfium::Optional instead of a boolean with an out parameter.
GetAttribute is then added to call TryAttribute to mirror the other
methods in the file.
Change-Id: I875dac120776af7c53fe069e4dd36e5486838447
Reviewed-on: https://pdfium-review.googlesource.com/18514
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

7 files changed, 69 insertions, 57 deletions

diff --git a/xfa/fxfa/parser/cxfa_dataexporter.cpp b/xfa/fxfa/parser/cxfa_dataexporter.cpp
index 35ad4adccf..f7715dc374 100644
--- a/xfa/fxfa/parser/cxfa_dataexporter.cpp
+++ b/xfa/fxfa/parser/cxfa_dataexporter.cpp
@@ -90,16 +90,18 @@ void SaveAttribute(CXFA_Node* pNode,
                    const WideStringView& wsName,
                    bool bProto,
                    WideString& wsOutput) {
-  WideString wsValue;
-  if ((!bProto && !pNode->JSNode()->HasAttribute(eName)) ||
-      !pNode->JSNode()->GetAttribute(eName, wsValue, false)) {
+  if (!bProto && !pNode->JSNode()->HasAttribute(eName))
     return;
-  }
-  wsValue = ExportEncodeAttribute(wsValue);
+
+  pdfium::Optional<WideString> value =
+      pNode->JSNode()->TryAttribute(eName, false);
+  if (!value)
+    return;
+
   wsOutput += L" ";
   wsOutput += wsName;
   wsOutput += L"=\"";
-  wsOutput += wsValue;
+  wsOutput += ExportEncodeAttribute(*value);
   wsOutput += L"\"";
 }
 
@@ -196,11 +198,10 @@ void RegenerateFormFile_Changed(CXFA_Node* pNode,
       if (!pRawValueNode)
         break;
 
-      WideString wsContentType;
-      pNode->JSNode()->GetAttribute(XFA_Attribute::ContentType, wsContentType,
-                                    false);
+      pdfium::Optional<WideString> contentType =
+          pNode->JSNode()->TryAttribute(XFA_Attribute::ContentType, false);
       if (pRawValueNode->GetElementType() == XFA_Element::SharpxHTML &&
-          wsContentType == L"text/html") {
+          (contentType && *contentType == L"text/html")) {
         CFX_XMLNode* pExDataXML = pNode->GetXMLMappingNode();
         if (!pExDataXML)
           break;
@@ -219,25 +220,25 @@ void RegenerateFormFile_Changed(CXFA_Node* pNode,
         wsChildren += WideString::FromUTF8(
             ByteStringView(pMemStream->GetBuffer(), pMemStream->GetSize()));
       } else if (pRawValueNode->GetElementType() == XFA_Element::Sharpxml &&
-                 wsContentType == L"text/xml") {
-        WideString wsRawValue;
-        pRawValueNode->JSNode()->GetAttribute(XFA_Attribute::Value, wsRawValue,
-                                              false);
-        if (wsRawValue.IsEmpty())
+                 (contentType && *contentType == L"text/xml")) {
+        pdfium::Optional<WideString> rawValue =
+            pRawValueNode->JSNode()->TryAttribute(XFA_Attribute::Value, false);
+        if (!rawValue || rawValue->IsEmpty())
           break;
 
         std::vector<WideString> wsSelTextArray;
         size_t iStart = 0;
-        auto iEnd = wsRawValue.Find(L'\n', iStart);
-        iEnd = !iEnd.has_value() ? wsRawValue.GetLength() : iEnd;
+        auto iEnd = rawValue->Find(L'\n', iStart);
+        iEnd = !iEnd.has_value() ? rawValue->GetLength() : iEnd;
         while (iEnd.has_value() && iEnd >= iStart) {
           wsSelTextArray.push_back(
-              wsRawValue.Mid(iStart, iEnd.value() - iStart));
+              rawValue->Mid(iStart, iEnd.value() - iStart));
           iStart = iEnd.value() + 1;
-          if (iStart >= wsRawValue.GetLength())
+          if (iStart >= rawValue->GetLength())
             break;
-          iEnd = wsRawValue.Find(L'\n', iStart);
+          iEnd = rawValue->Find(L'\n', iStart);
         }
+
         CXFA_Node* pParentNode = pNode->GetNodeItem(XFA_NODEITEM_Parent);
         ASSERT(pParentNode);
         CXFA_Node* pGrandparentNode =
diff --git a/xfa/fxfa/parser/cxfa_imagedata.cpp b/xfa/fxfa/parser/cxfa_imagedata.cpp
index 2ad891d7ec..7888c34205 100644
--- a/xfa/fxfa/parser/cxfa_imagedata.cpp
+++ b/xfa/fxfa/parser/cxfa_imagedata.cpp
@@ -35,7 +35,13 @@ bool CXFA_ImageData::GetHref(WideString& wsHref) {
     wsHref = *ret;
     return true;
   }
-  return m_pNode->JSNode()->GetAttribute(XFA_Attribute::Href, wsHref, true);
+  pdfium::Optional<WideString> ret =
+      m_pNode->JSNode()->TryAttribute(XFA_Attribute::Href, true);
+  if (!ret)
+    return false;
+
+  wsHref = *ret;
+  return true;
 }
 
 XFA_ATTRIBUTEENUM CXFA_ImageData::GetTransferEncoding() {
diff --git a/xfa/fxfa/parser/cxfa_measurement.cpp b/xfa/fxfa/parser/cxfa_measurement.cpp
index 053f9d1c47..91e39af969 100644
--- a/xfa/fxfa/parser/cxfa_measurement.cpp
+++ b/xfa/fxfa/parser/cxfa_measurement.cpp
@@ -45,36 +45,38 @@ void CXFA_Measurement::SetString(const WideStringView& wsMeasure) {
   Set(fValue, eUnit);
 }
 
-bool CXFA_Measurement::ToString(WideString* wsMeasure) const {
+WideString CXFA_Measurement::ToString() const {
+  WideString wsMeasure;
   switch (GetUnit()) {
     case XFA_Unit::Mm:
-      wsMeasure->Format(L"%.8gmm", GetValue());
-      return true;
+      wsMeasure.Format(L"%.8gmm", GetValue());
+      break;
     case XFA_Unit::Pt:
-      wsMeasure->Format(L"%.8gpt", GetValue());
-      return true;
+      wsMeasure.Format(L"%.8gpt", GetValue());
+      break;
     case XFA_Unit::In:
-      wsMeasure->Format(L"%.8gin", GetValue());
-      return true;
+      wsMeasure.Format(L"%.8gin", GetValue());
+      break;
     case XFA_Unit::Cm:
-      wsMeasure->Format(L"%.8gcm", GetValue());
-      return true;
+      wsMeasure.Format(L"%.8gcm", GetValue());
+      break;
     case XFA_Unit::Mp:
-      wsMeasure->Format(L"%.8gmp", GetValue());
-      return true;
+      wsMeasure.Format(L"%.8gmp", GetValue());
+      break;
     case XFA_Unit::Pc:
-      wsMeasure->Format(L"%.8gpc", GetValue());
-      return true;
+      wsMeasure.Format(L"%.8gpc", GetValue());
+      break;
     case XFA_Unit::Em:
-      wsMeasure->Format(L"%.8gem", GetValue());
-      return true;
+      wsMeasure.Format(L"%.8gem", GetValue());
+      break;
     case XFA_Unit::Percent:
-      wsMeasure->Format(L"%.8g%%", GetValue());
-      return true;
+      wsMeasure.Format(L"%.8g%%", GetValue());
+      break;
     default:
-      wsMeasure->Format(L"%.8g", GetValue());
-      return false;
+      wsMeasure.Format(L"%.8g", GetValue());
+      break;
   }
+  return wsMeasure;
 }
 
 float CXFA_Measurement::ToUnit(XFA_Unit eUnit) const {
diff --git a/xfa/fxfa/parser/cxfa_measurement.h b/xfa/fxfa/parser/cxfa_measurement.h
index 2f6af3d43c..d83af246b8 100644
--- a/xfa/fxfa/parser/cxfa_measurement.h
+++ b/xfa/fxfa/parser/cxfa_measurement.h
@@ -27,7 +27,7 @@ class CXFA_Measurement {
   XFA_Unit GetUnit() const { return m_eUnit; }
   float GetValue() const { return m_fValue; }
 
-  bool ToString(WideString* wsMeasure) const;
+  WideString ToString() const;
   float ToUnit(XFA_Unit eUnit) const;
 
  private:
diff --git a/xfa/fxfa/parser/cxfa_node.cpp b/xfa/fxfa/parser/cxfa_node.cpp
index 90579ff5e2..465529e777 100644
--- a/xfa/fxfa/parser/cxfa_node.cpp
+++ b/xfa/fxfa/parser/cxfa_node.cpp
@@ -198,8 +198,9 @@ CXFA_Node* CXFA_Node::Clone(bool bRecursive) {
   if (IsNeedSavingXMLNode()) {
     std::unique_ptr<CFX_XMLNode> pCloneXML;
     if (IsAttributeInXML()) {
-      WideString wsName;
-      JSNode()->GetAttribute(XFA_Attribute::Name, wsName, false);
+      WideString wsName = JSNode()
+                              ->TryAttribute(XFA_Attribute::Name, false)
+                              .value_or(WideString());
       auto pCloneXMLElement = pdfium::MakeUnique<CFX_XMLElement>(wsName);
       WideString wsValue = JSNode()->GetCData(XFA_Attribute::Value);
       if (!wsValue.IsEmpty())
@@ -867,8 +868,10 @@ bool CXFA_Node::RemoveChild(CXFA_Node* pNode, bool bNotify) {
             pNode->JSNode()->GetCData(XFA_Attribute::QualifiedName);
         pXMLElement->RemoveAttribute(wsAttributeName.c_str());
       }
-      WideString wsName;
-      pNode->JSNode()->GetAttribute(XFA_Attribute::Name, wsName, false);
+
+      WideString wsName = pNode->JSNode()
+                              ->TryAttribute(XFA_Attribute::Name, false)
+                              .value_or(WideString());
       CFX_XMLElement* pNewXMLElement = new CFX_XMLElement(wsName);
       WideString wsValue = JSNode()->GetCData(XFA_Attribute::Value);
       if (!wsValue.IsEmpty())
diff --git a/xfa/fxfa/parser/cxfa_nodelocale.cpp b/xfa/fxfa/parser/cxfa_nodelocale.cpp
index 25086922a7..da64c4a04c 100644
--- a/xfa/fxfa/parser/cxfa_nodelocale.cpp
+++ b/xfa/fxfa/parser/cxfa_nodelocale.cpp
@@ -135,11 +135,9 @@ CXFA_Node* CXFA_NodeLocale::GetNodeByName(CXFA_Node* pParent,
   CXFA_Node* pChild =
       pParent ? pParent->GetNodeItem(XFA_NODEITEM_FirstChild) : nullptr;
   while (pChild) {
-    WideString wsChild;
-    if (pChild->JSNode()->GetAttribute(XFA_Attribute::Name, wsChild, true)) {
-      if (wsChild == wsName)
-        return pChild;
-    }
+    if (pChild->JSNode()->GetAttribute(XFA_Attribute::Name) == wsName)
+      return pChild;
+
     pChild = pChild->GetNodeItem(XFA_NODEITEM_NextSibling);
   }
   return nullptr;
diff --git a/xfa/fxfa/parser/xfa_document_datamerger_imp.cpp b/xfa/fxfa/parser/xfa_document_datamerger_imp.cpp
index 29bcd5f3b9..4cf7601531 100644
--- a/xfa/fxfa/parser/xfa_document_datamerger_imp.cpp
+++ b/xfa/fxfa/parser/xfa_document_datamerger_imp.cpp
@@ -88,13 +88,15 @@ bool FormValueNode_SetChildContent(CXFA_Node* pValueNode,
       if (!pContentRawDataNode) {
         XFA_Element element = XFA_Element::Sharptext;
         if (pChildNode->GetElementType() == XFA_Element::ExData) {
-          WideString wsContentType;
-          pChildNode->JSNode()->GetAttribute(XFA_Attribute::ContentType,
-                                             wsContentType, false);
-          if (wsContentType == L"text/html")
-            element = XFA_Element::SharpxHTML;
-          else if (wsContentType == L"text/xml")
-            element = XFA_Element::Sharpxml;
+          pdfium::Optional<WideString> contentType =
+              pChildNode->JSNode()->TryAttribute(XFA_Attribute::ContentType,
+                                                 false);
+          if (contentType) {
+            if (*contentType == L"text/html")
+              element = XFA_Element::SharpxHTML;
+            else if (*contentType == L"text/xml")
+              element = XFA_Element::Sharpxml;
+          }
         }
         pContentRawDataNode = pChildNode->CreateSamePacketNode(element);
         pChildNode->InsertChild(pContentRawDataNode, nullptr);