Add observer for BAAnnots from Javascript

This Cl moves the observer code from the CPDFSDK_Widget up into the
CPDFSDK_Annot base class and then adds a second observer for CPDFSDK_BAAnnot
objects.

This allows us to attach an observer to the Annot javascript class which will
update its internal pointer to the BAAnnot if the BAAnnot is destroyed by
the CPDFSDK_PageView being destroyed.

BUG=chromium:642307

Review-Url: https://codereview.chromium.org/2306663002

7 files changed, 82 insertions, 58 deletions

diff --git a/fpdfsdk/cpdfsdk_annot.cpp b/fpdfsdk/cpdfsdk_annot.cpp
index 59d8f24e82..353edaaaf9 100644
--- a/fpdfsdk/cpdfsdk_annot.cpp
+++ b/fpdfsdk/cpdfsdk_annot.cpp
@@ -9,6 +9,7 @@
 #include <algorithm>
 
 #include "fpdfsdk/include/fsdk_mgr.h"
+#include "third_party/base/stl_util.h"
 
 #ifdef PDF_ENABLE_XFA
 #include "fpdfsdk/fpdfxfa/include/fpdfxfa_doc.h"
@@ -21,10 +22,39 @@ const float kMinHeight = 1.0f;
 
 }  // namespace
 
+CPDFSDK_Annot::Observer::Observer(CPDFSDK_Annot** pWatchedPtr)
+    : m_pWatchedPtr(pWatchedPtr) {
+  (*m_pWatchedPtr)->AddObserver(this);
+}
+
+CPDFSDK_Annot::Observer::~Observer() {
+  if (m_pWatchedPtr)
+    (*m_pWatchedPtr)->RemoveObserver(this);
+}
+
+void CPDFSDK_Annot::Observer::OnAnnotDestroyed() {
+  ASSERT(m_pWatchedPtr);
+  *m_pWatchedPtr = nullptr;
+  m_pWatchedPtr = nullptr;
+}
+
 CPDFSDK_Annot::CPDFSDK_Annot(CPDFSDK_PageView* pPageView)
     : m_pPageView(pPageView), m_bSelected(FALSE) {}
 
-CPDFSDK_Annot::~CPDFSDK_Annot() {}
+CPDFSDK_Annot::~CPDFSDK_Annot() {
+  for (auto* pObserver : m_Observers)
+    pObserver->OnAnnotDestroyed();
+}
+
+void CPDFSDK_Annot::AddObserver(Observer* pObserver) {
+  ASSERT(!pdfium::ContainsKey(m_Observers, pObserver));
+  m_Observers.insert(pObserver);
+}
+
+void CPDFSDK_Annot::RemoveObserver(Observer* pObserver) {
+  ASSERT(pdfium::ContainsKey(m_Observers, pObserver));
+  m_Observers.erase(pObserver);
+}
 
 #ifdef PDF_ENABLE_XFA
 
diff --git a/fpdfsdk/cpdfsdk_widget.cpp b/fpdfsdk/cpdfsdk_widget.cpp
index 73ba23d076..2ddbccc28c 100644
--- a/fpdfsdk/cpdfsdk_widget.cpp
+++ b/fpdfsdk/cpdfsdk_widget.cpp
@@ -26,7 +26,6 @@
 #include "fpdfsdk/include/fsdk_mgr.h"
 #include "fpdfsdk/pdfwindow/PWL_Edit.h"
 #include "fpdfsdk/pdfwindow/PWL_Utils.h"
-#include "third_party/base/stl_util.h"
 
 #ifdef PDF_ENABLE_XFA
 #include "fpdfsdk/fpdfxfa/include/fpdfxfa_doc.h"
@@ -37,22 +36,6 @@
 #include "xfa/fxfa/include/xfa_ffwidgethandler.h"
 #endif  // PDF_ENABLE_XFA
 
-CPDFSDK_Widget::Observer::Observer(CPDFSDK_Widget** pWatchedPtr)
-    : m_pWatchedPtr(pWatchedPtr) {
-  (*m_pWatchedPtr)->AddObserver(this);
-}
-
-CPDFSDK_Widget::Observer::~Observer() {
-  if (m_pWatchedPtr)
-    (*m_pWatchedPtr)->RemoveObserver(this);
-}
-
-void CPDFSDK_Widget::Observer::OnWidgetDestroyed() {
-  ASSERT(m_pWatchedPtr);
-  *m_pWatchedPtr = nullptr;
-  m_pWatchedPtr = nullptr;
-}
-
 CPDFSDK_Widget::CPDFSDK_Widget(CPDF_Annot* pAnnot,
                                CPDFSDK_PageView* pPageView,
                                CPDFSDK_InterForm* pInterForm)
@@ -68,20 +51,7 @@ CPDFSDK_Widget::CPDFSDK_Widget(CPDF_Annot* pAnnot,
 {
 }
 
-CPDFSDK_Widget::~CPDFSDK_Widget() {
-  for (auto* pObserver : m_Observers)
-    pObserver->OnWidgetDestroyed();
-}
-
-void CPDFSDK_Widget::AddObserver(Observer* pObserver) {
-  ASSERT(!pdfium::ContainsKey(m_Observers, pObserver));
-  m_Observers.insert(pObserver);
-}
-
-void CPDFSDK_Widget::RemoveObserver(Observer* pObserver) {
-  ASSERT(pdfium::ContainsKey(m_Observers, pObserver));
-  m_Observers.erase(pObserver);
-}
+CPDFSDK_Widget::~CPDFSDK_Widget() {}
 
 #ifdef PDF_ENABLE_XFA
 CXFA_FFWidget* CPDFSDK_Widget::GetMixXFAWidget() const {
diff --git a/fpdfsdk/include/cpdfsdk_annot.h b/fpdfsdk/include/cpdfsdk_annot.h
index 967226e9db..a43b8775db 100644
--- a/fpdfsdk/include/cpdfsdk_annot.h
+++ b/fpdfsdk/include/cpdfsdk_annot.h
@@ -23,9 +23,22 @@ class CPDFSDK_PageView;
 
 class CPDFSDK_Annot {
  public:
+  class Observer {
+   public:
+    explicit Observer(CPDFSDK_Annot** pWatchedPtr);
+    ~Observer();
+    void OnAnnotDestroyed();
+
+   private:
+    CPDFSDK_Annot** m_pWatchedPtr;
+  };
+
   explicit CPDFSDK_Annot(CPDFSDK_PageView* pPageView);
   virtual ~CPDFSDK_Annot();
 
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
 #ifdef PDF_ENABLE_XFA
   virtual FX_BOOL IsXFAField();
   virtual CXFA_FFWidget* GetXFAWidget() const;
@@ -57,6 +70,7 @@ class CPDFSDK_Annot {
   void SetSelected(FX_BOOL bSelected);
 
  protected:
+  std::set<Observer*> m_Observers;
   CPDFSDK_PageView* m_pPageView;
   FX_BOOL m_bSelected;
 };
diff --git a/fpdfsdk/include/cpdfsdk_widget.h b/fpdfsdk/include/cpdfsdk_widget.h
index 51116f9581..88692d553e 100644
--- a/fpdfsdk/include/cpdfsdk_widget.h
+++ b/fpdfsdk/include/cpdfsdk_widget.h
@@ -35,17 +35,6 @@ class CXFA_FFWidgetHandler;
 
 class CPDFSDK_Widget : public CPDFSDK_BAAnnot {
  public:
-  class Observer {
-   public:
-    explicit Observer(CPDFSDK_Widget** pWatchedPtr);
-    ~Observer();
-
-    void OnWidgetDestroyed();
-
-   private:
-    CPDFSDK_Widget** m_pWatchedPtr;
-  };
-
 #ifdef PDF_ENABLE_XFA
   CXFA_FFWidget* GetMixXFAWidget() const;
   CXFA_FFWidget* GetGroupMixXFAWidget();
@@ -75,9 +64,6 @@ class CPDFSDK_Widget : public CPDFSDK_BAAnnot {
                  CPDFSDK_InterForm* pInterForm);
   ~CPDFSDK_Widget() override;
 
-  void AddObserver(Observer* observer);
-  void RemoveObserver(Observer* observer);
-
   bool IsSignatureWidget() const override;
   CPDF_Action GetAAction(CPDF_AAction::AActionType eAAT) override;
   FX_BOOL IsAppearanceValid() override;
@@ -180,7 +166,6 @@ class CPDFSDK_Widget : public CPDFSDK_BAAnnot {
   FX_BOOL m_bAppModified;
   int32_t m_nAppAge;
   int32_t m_nValueAge;
-  std::set<Observer*> m_Observers;
 
 #ifdef PDF_ENABLE_XFA
   mutable CXFA_FFWidget* m_hMixXFAWidget;
diff --git a/fpdfsdk/javascript/Annot.cpp b/fpdfsdk/javascript/Annot.cpp
index a23d42f72a..ab84247baa 100644
--- a/fpdfsdk/javascript/Annot.cpp
+++ b/fpdfsdk/javascript/Annot.cpp
@@ -11,6 +11,14 @@
 #include "fpdfsdk/javascript/JS_Value.h"
 #include "fpdfsdk/javascript/cjs_context.h"
 
+namespace {
+
+CPDFSDK_BAAnnot* ToBAAnnot(CPDFSDK_Annot* annot) {
+  return static_cast<CPDFSDK_BAAnnot*>(annot);
+}
+
+}  // namespace
+
 BEGIN_JS_STATIC_CONST(CJS_Annot)
 END_JS_STATIC_CONST()
 
@@ -32,8 +40,12 @@ Annot::~Annot() {}
 FX_BOOL Annot::hidden(IJS_Context* cc,
                       CJS_PropValue& vp,
                       CFX_WideString& sError) {
+  CPDFSDK_BAAnnot* baAnnot = ToBAAnnot(m_pAnnot);
+  if (!baAnnot)
+    return FALSE;
+
   if (vp.IsGetting()) {
-    CPDF_Annot* pPDFAnnot = m_BAAnnot->GetPDFAnnot();
+    CPDF_Annot* pPDFAnnot = baAnnot->GetPDFAnnot();
     vp << CPDF_Annot::IsAnnotationHidden(pPDFAnnot->GetAnnotDict());
     return TRUE;
   }
@@ -41,7 +53,7 @@ FX_BOOL Annot::hidden(IJS_Context* cc,
   bool bHidden;
   vp >> bHidden;
 
-  uint32_t flags = m_BAAnnot->GetFlags();
+  uint32_t flags = baAnnot->GetFlags();
   if (bHidden) {
     flags |= ANNOTFLAG_HIDDEN;
     flags |= ANNOTFLAG_INVISIBLE;
@@ -53,21 +65,25 @@ FX_BOOL Annot::hidden(IJS_Context* cc,
     flags &= ~ANNOTFLAG_NOVIEW;
     flags |= ANNOTFLAG_PRINT;
   }
-  m_BAAnnot->SetFlags(flags);
+  baAnnot->SetFlags(flags);
   return TRUE;
 }
 
 FX_BOOL Annot::name(IJS_Context* cc,
                     CJS_PropValue& vp,
                     CFX_WideString& sError) {
+  CPDFSDK_BAAnnot* baAnnot = ToBAAnnot(m_pAnnot);
+  if (!baAnnot)
+    return FALSE;
+
   if (vp.IsGetting()) {
-    vp << m_BAAnnot->GetAnnotName();
+    vp << baAnnot->GetAnnotName();
     return TRUE;
   }
 
   CFX_WideString annotName;
   vp >> annotName;
-  m_BAAnnot->SetAnnotName(annotName);
+  baAnnot->SetAnnotName(annotName);
   return TRUE;
 }
 
@@ -80,10 +96,15 @@ FX_BOOL Annot::type(IJS_Context* cc,
     return FALSE;
   }
 
-  vp << CPDF_Annot::AnnotSubtypeToString(m_BAAnnot->GetAnnotSubtype());
+  CPDFSDK_BAAnnot* baAnnot = ToBAAnnot(m_pAnnot);
+  if (!baAnnot)
+    return FALSE;
+
+  vp << CPDF_Annot::AnnotSubtypeToString(baAnnot->GetAnnotSubtype());
   return TRUE;
 }
 
 void Annot::SetSDKAnnot(CPDFSDK_BAAnnot* annot) {
-  m_BAAnnot = annot;
+  m_pAnnot = annot;
+  m_pObserver.reset(new CPDFSDK_Annot::Observer(&m_pAnnot));
 }
diff --git a/fpdfsdk/javascript/Annot.h b/fpdfsdk/javascript/Annot.h
index b3ea292aed..be850350ae 100644
--- a/fpdfsdk/javascript/Annot.h
+++ b/fpdfsdk/javascript/Annot.h
@@ -7,6 +7,8 @@
 #ifndef FPDFSDK_JAVASCRIPT_ANNOT_H_
 #define FPDFSDK_JAVASCRIPT_ANNOT_H_
 
+#include <memory>
+
 #include "fpdfsdk/include/cpdfsdk_baannot.h"
 #include "fpdfsdk/javascript/JS_Define.h"
 
@@ -22,7 +24,8 @@ class Annot : public CJS_EmbedObj {
   void SetSDKAnnot(CPDFSDK_BAAnnot* annot);
 
  private:
-  CPDFSDK_BAAnnot* m_BAAnnot = nullptr;
+  CPDFSDK_Annot* m_pAnnot = nullptr;
+  std::unique_ptr<CPDFSDK_Annot::Observer> m_pObserver;
 };
 
 class CJS_Annot : public CJS_Object {
diff --git a/fpdfsdk/javascript/Field.cpp b/fpdfsdk/javascript/Field.cpp
index 5c279d6b53..3f5e5e1b0f 100644
--- a/fpdfsdk/javascript/Field.cpp
+++ b/fpdfsdk/javascript/Field.cpp
@@ -267,11 +267,12 @@ void Field::UpdateFormField(CPDFSDK_Document* pDocument,
   if (bResetAP) {
     int nFieldType = pFormField->GetFieldType();
     if (nFieldType == FIELDTYPE_COMBOBOX || nFieldType == FIELDTYPE_TEXTFIELD) {
-      for (CPDFSDK_Widget* pWidget : widgets) {
+      for (CPDFSDK_Annot* pAnnot : widgets) {
         FX_BOOL bFormatted = FALSE;
-        CPDFSDK_Widget::Observer observer(&pWidget);
+        CPDFSDK_Widget* pWidget = static_cast<CPDFSDK_Widget*>(pAnnot);
+        CPDFSDK_Widget::Observer observer(&pAnnot);
         CFX_WideString sValue = pWidget->OnFormat(bFormatted);
-        if (pWidget) {
+        if (pAnnot) {
           pWidget->ResetAppearance(bFormatted ? sValue.c_str() : nullptr,
                                    FALSE);
         }