Rename GetItem to GetItemIfExists

Rename GetItem to make it clearer it can return nullptr.

Change-Id: I0e09a79c3e2244b08212d3b51d3ad0e6a86edfd9
Reviewed-on: https://pdfium-review.googlesource.com/22713
Reviewed-by: Ryan Harrison <rharrison@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

4 files changed, 37 insertions, 13 deletions

diff --git a/fxjs/xfa/cjx_instancemanager.cpp b/fxjs/xfa/cjx_instancemanager.cpp
index d6ac66d9df..830541ed7c 100644
--- a/fxjs/xfa/cjx_instancemanager.cpp
+++ b/fxjs/xfa/cjx_instancemanager.cpp
@@ -58,8 +58,15 @@ int32_t CJX_InstanceManager::SetInstances(int32_t iDesired) {
             : wsInstManagerName.Right(wsInstManagerName.GetLength() - 1));
     uint32_t dInstanceNameHash =
         FX_HashCode_GetW(wsInstanceName.AsStringView(), false);
-    CXFA_Node* pPrevSibling =
-        iDesired == 0 ? GetXFANode() : GetXFANode()->GetItem(iDesired - 1);
+    CXFA_Node* pPrevSibling = iDesired == 0
+                                  ? GetXFANode()
+                                  : GetXFANode()->GetItemIfExists(iDesired - 1);
+    if (!pPrevSibling) {
+      // TODO(dsinclair): Better error?
+      ThrowIndexOutOfBoundsException();
+      return 0;
+    }
+
     while (iCount > iDesired) {
       CXFA_Node* pRemoveInstance = pPrevSibling->GetNextSibling();
       if (pRemoveInstance->GetElementType() != XFA_Element::Subform &&
@@ -109,7 +116,12 @@ int32_t CJX_InstanceManager::MoveInstance(int32_t iTo, int32_t iFrom) {
   if (iFrom < 0 || iTo < 0 || iFrom == iTo)
     return 0;
 
-  CXFA_Node* pMoveInstance = GetXFANode()->GetItem(iFrom);
+  CXFA_Node* pMoveInstance = GetXFANode()->GetItemIfExists(iFrom);
+  if (!pMoveInstance) {
+    ThrowIndexOutOfBoundsException();
+    return 1;
+  }
+
   GetXFANode()->RemoveItem(pMoveInstance, false);
   GetXFANode()->InsertItem(pMoveInstance, iTo, iCount - 1, true);
   CXFA_LayoutProcessor* pLayoutPro = GetDocument()->GetLayoutProcessor();
@@ -134,11 +146,11 @@ CJS_Return CJX_InstanceManager::moveInstance(
   if (!pNotify)
     return CJS_Return(true);
 
-  CXFA_Node* pToInstance = GetXFANode()->GetItem(iTo);
+  CXFA_Node* pToInstance = GetXFANode()->GetItemIfExists(iTo);
   if (pToInstance && pToInstance->GetElementType() == XFA_Element::Subform)
     pNotify->RunSubformIndexChange(pToInstance);
 
-  CXFA_Node* pFromInstance = GetXFANode()->GetItem(iFrom);
+  CXFA_Node* pFromInstance = GetXFANode()->GetItemIfExists(iFrom);
   if (pFromInstance &&
       pFromInstance->GetElementType() == XFA_Element::Subform) {
     pNotify->RunSubformIndexChange(pFromInstance);
@@ -163,13 +175,16 @@ CJS_Return CJX_InstanceManager::removeInstance(
   if (iCount - 1 < iMin)
     return CJS_Return(JSGetStringFromID(JSMessage::kTooManyOccurances));
 
-  CXFA_Node* pRemoveInstance = GetXFANode()->GetItem(iIndex);
+  CXFA_Node* pRemoveInstance = GetXFANode()->GetItemIfExists(iIndex);
+  if (!pRemoveInstance)
+    return CJS_Return(JSGetStringFromID(JSMessage::kParamError));
+
   GetXFANode()->RemoveItem(pRemoveInstance, true);
 
   CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
   if (pNotify) {
     for (int32_t i = iIndex; i < iCount - 1; i++) {
-      CXFA_Node* pSubformInstance = GetXFANode()->GetItem(i);
+      CXFA_Node* pSubformInstance = GetXFANode()->GetItemIfExists(i);
       if (pSubformInstance &&
           pSubformInstance->GetElementType() == XFA_Element::Subform) {
         pNotify->RunSubformIndexChange(pSubformInstance);
diff --git a/fxjs/xfa/cjx_object.cpp b/fxjs/xfa/cjx_object.cpp
index cb76497618..8608cc0e8d 100644
--- a/fxjs/xfa/cjx_object.cpp
+++ b/fxjs/xfa/cjx_object.cpp
@@ -1629,12 +1629,12 @@ void CJX_Object::Script_Som_InstanceIndex(CFXJSE_Value* pValue,
   if (!pNotify)
     return;
 
-  CXFA_Node* pToInstance = pManagerNode->GetItem(iTo);
+  CXFA_Node* pToInstance = pManagerNode->GetItemIfExists(iTo);
   if (pToInstance && pToInstance->GetElementType() == XFA_Element::Subform) {
     pNotify->RunSubformIndexChange(pToInstance);
   }
 
-  CXFA_Node* pFromInstance = pManagerNode->GetItem(iFrom);
+  CXFA_Node* pFromInstance = pManagerNode->GetItemIfExists(iFrom);
   if (pFromInstance &&
       pFromInstance->GetElementType() == XFA_Element::Subform) {
     pNotify->RunSubformIndexChange(pFromInstance);
diff --git a/xfa/fxfa/parser/cxfa_node.cpp b/xfa/fxfa/parser/cxfa_node.cpp
index c29e30347f..075ee46836 100644
--- a/xfa/fxfa/parser/cxfa_node.cpp
+++ b/xfa/fxfa/parser/cxfa_node.cpp
@@ -1129,7 +1129,7 @@ bool CXFA_Node::IsNeedSavingXMLNode() {
                         GetElementType() == XFA_Element::Xfa);
 }
 
-CXFA_Node* CXFA_Node::GetItem(int32_t iIndex) {
+CXFA_Node* CXFA_Node::GetItemIfExists(int32_t iIndex) {
   int32_t iCount = 0;
   uint32_t dwNameHash = 0;
   for (CXFA_Node* pNode = GetNextSibling(); pNode;
@@ -1198,8 +1198,12 @@ void CXFA_Node::InsertItem(CXFA_Node* pNewInstance,
   if (iPos < 0)
     iPos = iCount;
   if (iPos == iCount) {
+    CXFA_Node* item = GetItemIfExists(iCount - 1);
+    if (!item)
+      return;
+
     CXFA_Node* pNextSibling =
-        iCount > 0 ? GetItem(iCount - 1)->GetNextSibling() : GetNextSibling();
+        iCount > 0 ? item->GetNextSibling() : GetNextSibling();
     GetParent()->InsertChild(pNewInstance, pNextSibling);
     if (bMoveDataBindingNodes) {
       std::set<CXFA_Node*> sNew;
@@ -1229,7 +1233,12 @@ void CXFA_Node::InsertItem(CXFA_Node* pNewInstance,
       ReorderDataNodes(sNew, sAfter, false);
     }
   } else {
-    CXFA_Node* pBeforeInstance = GetItem(iPos);
+    CXFA_Node* pBeforeInstance = GetItemIfExists(iPos);
+    if (!pBeforeInstance) {
+      // TODO(dsinclair): What should happen here?
+      return;
+    }
+
     GetParent()->InsertChild(pNewInstance, pBeforeInstance);
     if (bMoveDataBindingNodes) {
       std::set<CXFA_Node*> sNew;
diff --git a/xfa/fxfa/parser/cxfa_node.h b/xfa/fxfa/parser/cxfa_node.h
index 1e20ace09c..8108eeccc4 100644
--- a/xfa/fxfa/parser/cxfa_node.h
+++ b/xfa/fxfa/parser/cxfa_node.h
@@ -104,7 +104,7 @@ class CXFA_Node : public CXFA_Object {
 
   CXFA_Node* CreateInstanceIfPossible(bool bDataMerge);
   int32_t GetCount();
-  CXFA_Node* GetItem(int32_t iIndex);
+  CXFA_Node* GetItemIfExists(int32_t iIndex);
   void RemoveItem(CXFA_Node* pRemoveInstance, bool bRemoveDataBinding);
   void InsertItem(CXFA_Node* pNewInstance,
                   int32_t iPos,