Fixing crash on mouse movement in XFA form.

Bug: pdfium:868
Change-Id: Ifd39c5c7c5486560987c18e9afb6ae3d2a4b7454
Reviewed-on: https://pdfium-review.googlesource.com/11190
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>

2 files changed, 14 insertions, 12 deletions

diff --git a/fpdfsdk/cpdfsdk_pageview.cpp b/fpdfsdk/cpdfsdk_pageview.cpp
index 209e8de482..d2afe14de3 100644
--- a/fpdfsdk/cpdfsdk_pageview.cpp
+++ b/fpdfsdk/cpdfsdk_pageview.cpp
@@ -37,7 +37,6 @@ CPDFSDK_PageView::CPDFSDK_PageView(CPDFSDK_FormFillEnvironment* pFormFillEnv,
       m_bOwnsPage(false),
 #endif  // PDF_ENABLE_XFA
       m_bEnterWidget(false),
-      m_bExitWidget(false),
       m_bOnWidget(false),
       m_bValid(false),
       m_bLocked(false),
@@ -332,29 +331,37 @@ bool CPDFSDK_PageView::OnMouseMove(const CFX_PointF& point, int nFlag) {
   CPDFSDK_Annot::ObservedPtr pFXAnnot(GetFXAnnotAtPoint(point));
   if (pFXAnnot) {
     if (m_pCaptureWidget && m_pCaptureWidget != pFXAnnot) {
-      m_bExitWidget = true;
       m_bEnterWidget = false;
       pAnnotHandlerMgr->Annot_OnMouseExit(this, &m_pCaptureWidget, nFlag);
     }
-    m_pCaptureWidget.Reset(pFXAnnot.Get());
     m_bOnWidget = true;
+    m_pCaptureWidget.Reset(pFXAnnot.Get());
+
     if (!m_bEnterWidget) {
       m_bEnterWidget = true;
-      m_bExitWidget = false;
       pAnnotHandlerMgr->Annot_OnMouseEnter(this, &pFXAnnot, nFlag);
+
+      // Annot_OnMouseEnter may have invalidated pFXAnnot.
+      if (!pFXAnnot) {
+        m_bOnWidget = false;
+        m_bEnterWidget = false;
+        m_pCaptureWidget.Reset();
+        return true;
+      }
     }
     pAnnotHandlerMgr->Annot_OnMouseMove(this, &pFXAnnot, nFlag, point);
     return true;
   }
+
   if (m_bOnWidget) {
     m_bOnWidget = false;
-    m_bExitWidget = true;
     m_bEnterWidget = false;
     if (m_pCaptureWidget) {
       pAnnotHandlerMgr->Annot_OnMouseExit(this, &m_pCaptureWidget, nFlag);
       m_pCaptureWidget.Reset();
     }
   }
+
   return false;
 }
 
@@ -399,7 +406,8 @@ void CPDFSDK_PageView::LoadFXAnnots() {
   CPDFSDK_AnnotHandlerMgr* pAnnotHandlerMgr =
       m_pFormFillEnv->GetAnnotHandlerMgr();
 
-  SetLock(true);
+  CFX_AutoRestorer<bool> lock(&m_bLocked);
+  m_bLocked = true;
 
 #ifdef PDF_ENABLE_XFA
   CFX_RetainPtr<CPDFXFA_Page> protector(m_page);
@@ -410,7 +418,6 @@ void CPDFSDK_PageView::LoadFXAnnots() {
             XFA_TRAVERSEWAY_Form,
             XFA_WidgetStatus_Visible | XFA_WidgetStatus_Viewable));
     if (!pWidgetHandler) {
-      SetLock(false);
       return;
     }
 
@@ -422,7 +429,6 @@ void CPDFSDK_PageView::LoadFXAnnots() {
       pAnnotHandlerMgr->Annot_OnLoad(pAnnot);
     }
 
-    SetLock(false);
     return;
   }
 #endif  // PDF_ENABLE_XFA
@@ -445,8 +451,6 @@ void CPDFSDK_PageView::LoadFXAnnots() {
     m_SDKAnnotArray.push_back(pAnnot);
     pAnnotHandlerMgr->Annot_OnLoad(pAnnot);
   }
-
-  SetLock(false);
 }
 
 void CPDFSDK_PageView::UpdateRects(const std::vector<CFX_FloatRect>& rects) {
diff --git a/fpdfsdk/cpdfsdk_pageview.h b/fpdfsdk/cpdfsdk_pageview.h
index c525bfc457..face5072c7 100644
--- a/fpdfsdk/cpdfsdk_pageview.h
+++ b/fpdfsdk/cpdfsdk_pageview.h
@@ -88,7 +88,6 @@ class CPDFSDK_PageView final : public CPDF_Page::View {
   void SetValid(bool bValid) { m_bValid = bValid; }
   bool IsValid() { return m_bValid; }
 
-  void SetLock(bool bLocked) { m_bLocked = bLocked; }
   bool IsLocked() { return m_bLocked; }
 
   void SetBeingDestroyed() { m_bBeingDestroyed = true; }
@@ -115,7 +114,6 @@ class CPDFSDK_PageView final : public CPDF_Page::View {
   bool m_bOwnsPage;
 #endif  // PDF_ENABLE_XFA
   bool m_bEnterWidget;
-  bool m_bExitWidget;
   bool m_bOnWidget;
   bool m_bValid;
   bool m_bLocked;