[xfa] Move CJX code into fxjs/xfa

This CL moves the remaining CJX clases into fxjs/xfa so they co-exist
with the rest of the CJX classes.

Change-Id: I2b1e5504ac23f73df177f309967a04ab27fb61d1
Reviewed-on: https://pdfium-review.googlesource.com/20550
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

1 files changed, 639 insertions, 0 deletions

diff --git a/fxjs/xfa/cjx_hostpseudomodel.cpp b/fxjs/xfa/cjx_hostpseudomodel.cpp
new file mode 100644
index 0000000000..20e3bfe496
--- /dev/null
+++ b/fxjs/xfa/cjx_hostpseudomodel.cpp
@@ -0,0 +1,639 @@
+// Copyright 2017 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#include "fxjs/xfa/cjx_hostpseudomodel.h"
+
+#include <memory>
+#include <vector>
+
+#include "fxjs/cfxjse_engine.h"
+#include "fxjs/cfxjse_value.h"
+#include "fxjs/js_resources.h"
+#include "xfa/fxfa/cxfa_ffnotify.h"
+#include "xfa/fxfa/parser/cscript_hostpseudomodel.h"
+#include "xfa/fxfa/parser/cxfa_layoutprocessor.h"
+#include "xfa/fxfa/parser/cxfa_node.h"
+#include "xfa/fxfa/parser/xfa_resolvenode_rs.h"
+
+namespace {
+
+int32_t FilterName(const WideStringView& wsExpression,
+                   int32_t nStart,
+                   WideString& wsFilter) {
+  ASSERT(nStart > -1);
+  int32_t iLength = wsExpression.GetLength();
+  if (nStart >= iLength)
+    return iLength;
+
+  wchar_t* pBuf = wsFilter.GetBuffer(iLength - nStart);
+  int32_t nCount = 0;
+  const wchar_t* pSrc = wsExpression.unterminated_c_str();
+  wchar_t wCur;
+  while (nStart < iLength) {
+    wCur = pSrc[nStart++];
+    if (wCur == ',')
+      break;
+
+    pBuf[nCount++] = wCur;
+  }
+  wsFilter.ReleaseBuffer(nCount);
+  wsFilter.Trim();
+  return nStart;
+}
+
+}  // namespace
+
+const CJX_MethodSpec CJX_HostPseudoModel::MethodSpecs[] = {
+    {"beep", beep_static},
+    {"documentCountInBatch", documentCountInBatch_static},
+    {"documentInBatch", documentInBatch_static},
+    {"exportData", exportData_static},
+    {"getFocus", getFocus_static},
+    {"gotoURL", gotoURL_static},
+    {"importData", importData_static},
+    {"messageBox", messageBox_static},
+    {"openList", openList_static},
+    {"pageDown", pageDown_static},
+    {"pageUp", pageUp_static},
+    {"print", print_static},
+    {"resetData", resetData_static},
+    {"response", response_static},
+    {"setFocus", setFocus_static},
+    {"", nullptr}};
+
+CJX_HostPseudoModel::CJX_HostPseudoModel(CScript_HostPseudoModel* model)
+    : CJX_Object(model) {
+  DefineMethods(MethodSpecs);
+}
+
+CJX_HostPseudoModel::~CJX_HostPseudoModel() {}
+
+void CJX_HostPseudoModel::AppType(CFXJSE_Value* pValue,
+                                  bool bSetting,
+                                  XFA_Attribute eAttribute) {
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return;
+
+  if (bSetting) {
+    ThrowInvalidPropertyException();
+    return;
+  }
+  pValue->SetString("Exchange");
+}
+
+void CJX_HostPseudoModel::CalculationsEnabled(CFXJSE_Value* pValue,
+                                              bool bSetting,
+                                              XFA_Attribute eAttribute) {
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return;
+
+  CXFA_FFDoc* hDoc = pNotify->GetHDOC();
+  if (bSetting) {
+    pNotify->GetDocEnvironment()->SetCalculationsEnabled(hDoc,
+                                                         pValue->ToBoolean());
+    return;
+  }
+  pValue->SetBoolean(pNotify->GetDocEnvironment()->IsCalculationsEnabled(hDoc));
+}
+
+void CJX_HostPseudoModel::CurrentPage(CFXJSE_Value* pValue,
+                                      bool bSetting,
+                                      XFA_Attribute eAttribute) {
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return;
+
+  CXFA_FFDoc* hDoc = pNotify->GetHDOC();
+  if (bSetting) {
+    pNotify->GetDocEnvironment()->SetCurrentPage(hDoc, pValue->ToInteger());
+    return;
+  }
+  pValue->SetInteger(pNotify->GetDocEnvironment()->GetCurrentPage(hDoc));
+}
+
+void CJX_HostPseudoModel::Language(CFXJSE_Value* pValue,
+                                   bool bSetting,
+                                   XFA_Attribute eAttribute) {
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return;
+
+  if (bSetting) {
+    ThrowException(L"Unable to set language value.");
+    return;
+  }
+  pValue->SetString(
+      pNotify->GetAppProvider()->GetLanguage().UTF8Encode().AsStringView());
+}
+
+void CJX_HostPseudoModel::NumPages(CFXJSE_Value* pValue,
+                                   bool bSetting,
+                                   XFA_Attribute eAttribute) {
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return;
+
+  CXFA_FFDoc* hDoc = pNotify->GetHDOC();
+  if (bSetting) {
+    ThrowException(L"Unable to set numPages value.");
+    return;
+  }
+  pValue->SetInteger(pNotify->GetDocEnvironment()->CountPages(hDoc));
+}
+
+void CJX_HostPseudoModel::Platform(CFXJSE_Value* pValue,
+                                   bool bSetting,
+                                   XFA_Attribute eAttribute) {
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return;
+
+  if (bSetting) {
+    ThrowException(L"Unable to set platform value.");
+    return;
+  }
+  pValue->SetString(
+      pNotify->GetAppProvider()->GetPlatform().UTF8Encode().AsStringView());
+}
+
+void CJX_HostPseudoModel::Title(CFXJSE_Value* pValue,
+                                bool bSetting,
+                                XFA_Attribute eAttribute) {
+  if (!GetDocument()->GetScriptContext()->IsRunAtClient())
+    return;
+
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return;
+
+  CXFA_FFDoc* hDoc = pNotify->GetHDOC();
+  if (bSetting) {
+    pNotify->GetDocEnvironment()->SetTitle(hDoc, pValue->ToWideString());
+    return;
+  }
+
+  WideString wsTitle;
+  pNotify->GetDocEnvironment()->GetTitle(hDoc, wsTitle);
+  pValue->SetString(wsTitle.UTF8Encode().AsStringView());
+}
+
+void CJX_HostPseudoModel::ValidationsEnabled(CFXJSE_Value* pValue,
+                                             bool bSetting,
+                                             XFA_Attribute eAttribute) {
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return;
+
+  CXFA_FFDoc* hDoc = pNotify->GetHDOC();
+  if (bSetting) {
+    pNotify->GetDocEnvironment()->SetValidationsEnabled(hDoc,
+                                                        pValue->ToBoolean());
+    return;
+  }
+
+  bool bEnabled = pNotify->GetDocEnvironment()->IsValidationsEnabled(hDoc);
+  pValue->SetBoolean(bEnabled);
+}
+
+void CJX_HostPseudoModel::Variation(CFXJSE_Value* pValue,
+                                    bool bSetting,
+                                    XFA_Attribute eAttribute) {
+  if (!GetDocument()->GetScriptContext()->IsRunAtClient())
+    return;
+
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return;
+
+  if (bSetting) {
+    ThrowException(L"Unable to set variation value.");
+    return;
+  }
+  pValue->SetString("Full");
+}
+
+void CJX_HostPseudoModel::Version(CFXJSE_Value* pValue,
+                                  bool bSetting,
+                                  XFA_Attribute eAttribute) {
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return;
+
+  if (bSetting) {
+    ThrowException(L"Unable to set version value.");
+    return;
+  }
+  pValue->SetString("11");
+}
+
+void CJX_HostPseudoModel::Name(CFXJSE_Value* pValue,
+                               bool bSetting,
+                               XFA_Attribute eAttribute) {
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return;
+
+  if (bSetting) {
+    ThrowInvalidPropertyException();
+    return;
+  }
+  pValue->SetString(
+      pNotify->GetAppProvider()->GetAppName().UTF8Encode().AsStringView());
+}
+
+CJS_Return CJX_HostPseudoModel::gotoURL(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  if (!GetDocument()->GetScriptContext()->IsRunAtClient())
+    return CJS_Return(true);
+
+  if (params.size() != 1)
+    return CJS_Return(JSGetStringFromID(JSMessage::kParamError));
+
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return CJS_Return(true);
+
+  CXFA_FFDoc* hDoc = pNotify->GetHDOC();
+  WideString URL = runtime->ToWideString(params[0]);
+  pNotify->GetDocEnvironment()->GotoURL(hDoc, URL);
+  return CJS_Return(true);
+}
+
+CJS_Return CJX_HostPseudoModel::openList(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  if (!GetDocument()->GetScriptContext()->IsRunAtClient())
+    return CJS_Return(true);
+
+  if (params.size() != 1)
+    return CJS_Return(JSGetStringFromID(JSMessage::kParamError));
+
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return CJS_Return(true);
+
+  CXFA_Node* pNode = nullptr;
+  if (params[0]->IsObject()) {
+    pNode = ToNode(runtime->ToXFAObject(params[0]));
+  } else if (params[0]->IsString()) {
+    CFXJSE_Engine* pScriptContext = GetDocument()->GetScriptContext();
+    if (!pScriptContext)
+      return CJS_Return(true);
+
+    CXFA_Object* pObject = pScriptContext->GetThisObject();
+    if (!pObject)
+      return CJS_Return(true);
+
+    uint32_t dwFlag = XFA_RESOLVENODE_Children | XFA_RESOLVENODE_Parent |
+                      XFA_RESOLVENODE_Siblings;
+    XFA_RESOLVENODE_RS resolveNodeRS;
+    bool iRet = pScriptContext->ResolveObjects(
+        pObject, runtime->ToWideString(params[0]).AsStringView(),
+        &resolveNodeRS, dwFlag, nullptr);
+    if (!iRet || !resolveNodeRS.objects.front()->IsNode())
+      return CJS_Return(true);
+
+    pNode = resolveNodeRS.objects.front()->AsNode();
+  }
+
+  CXFA_LayoutProcessor* pDocLayout = GetDocument()->GetDocLayout();
+  if (!pDocLayout)
+    return CJS_Return(true);
+
+  CXFA_FFWidget* hWidget =
+      pNotify->GetHWidget(pDocLayout->GetLayoutItem(pNode));
+  if (!hWidget)
+    return CJS_Return(true);
+
+  pNotify->GetDocEnvironment()->SetFocusWidget(pNotify->GetHDOC(), hWidget);
+  pNotify->OpenDropDownList(hWidget);
+  return CJS_Return(true);
+}
+
+CJS_Return CJX_HostPseudoModel::response(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  if (params.empty() || params.size() > 4)
+    return CJS_Return(JSGetStringFromID(JSMessage::kParamError));
+
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return CJS_Return(true);
+
+  WideString question;
+  if (params.size() >= 1)
+    question = runtime->ToWideString(params[0]);
+
+  WideString title;
+  if (params.size() >= 2)
+    title = runtime->ToWideString(params[1]);
+
+  WideString defaultAnswer;
+  if (params.size() >= 3)
+    defaultAnswer = runtime->ToWideString(params[2]);
+
+  bool mark = false;
+  if (params.size() >= 4)
+    mark = runtime->ToInt32(params[3]) != 0;
+
+  WideString answer =
+      pNotify->GetAppProvider()->Response(question, title, defaultAnswer, mark);
+  return CJS_Return(runtime->NewString(answer.UTF8Encode().AsStringView()));
+}
+
+CJS_Return CJX_HostPseudoModel::documentInBatch(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  return CJS_Return(runtime->NewNumber(0));
+}
+
+CJS_Return CJX_HostPseudoModel::resetData(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  if (params.size() > 1)
+    return CJS_Return(JSGetStringFromID(JSMessage::kParamError));
+
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return CJS_Return(true);
+
+  WideString expression;
+  if (params.size() >= 1)
+    expression = runtime->ToWideString(params[0]);
+
+  if (expression.IsEmpty()) {
+    pNotify->ResetData();
+    return CJS_Return(true);
+  }
+
+  int32_t iStart = 0;
+  WideString wsName;
+  CXFA_Node* pNode = nullptr;
+  int32_t iExpLength = expression.GetLength();
+  while (iStart < iExpLength) {
+    iStart = FilterName(expression.AsStringView(), iStart, wsName);
+    CFXJSE_Engine* pScriptContext = GetDocument()->GetScriptContext();
+    if (!pScriptContext)
+      return CJS_Return(true);
+
+    CXFA_Object* pObject = pScriptContext->GetThisObject();
+    if (!pObject)
+      return CJS_Return(true);
+
+    uint32_t dwFlag = XFA_RESOLVENODE_Children | XFA_RESOLVENODE_Parent |
+                      XFA_RESOLVENODE_Siblings;
+    XFA_RESOLVENODE_RS resolveNodeRS;
+    bool iRet = pScriptContext->ResolveObjects(pObject, wsName.AsStringView(),
+                                               &resolveNodeRS, dwFlag, nullptr);
+    if (!iRet || !resolveNodeRS.objects.front()->IsNode())
+      continue;
+
+    pNode = resolveNodeRS.objects.front()->AsNode();
+    pNotify->ResetData(pNode->GetWidgetData());
+  }
+  if (!pNode)
+    pNotify->ResetData();
+
+  return CJS_Return(true);
+}
+
+CJS_Return CJX_HostPseudoModel::beep(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  if (!GetDocument()->GetScriptContext()->IsRunAtClient())
+    return CJS_Return(true);
+
+  if (params.size() > 1)
+    return CJS_Return(JSGetStringFromID(JSMessage::kParamError));
+
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return CJS_Return(true);
+
+  uint32_t dwType = 4;
+  if (params.size() >= 1)
+    dwType = runtime->ToInt32(params[0]);
+
+  pNotify->GetAppProvider()->Beep(dwType);
+  return CJS_Return(true);
+}
+
+CJS_Return CJX_HostPseudoModel::setFocus(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  if (!GetDocument()->GetScriptContext()->IsRunAtClient())
+    return CJS_Return(true);
+
+  if (params.size() != 1)
+    return CJS_Return(JSGetStringFromID(JSMessage::kParamError));
+
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return CJS_Return(true);
+
+  CXFA_Node* pNode = nullptr;
+  if (params.size() >= 1) {
+    if (params[0]->IsObject()) {
+      pNode = ToNode(runtime->ToXFAObject(params[0]));
+    } else if (params[0]->IsString()) {
+      CFXJSE_Engine* pScriptContext = GetDocument()->GetScriptContext();
+      if (!pScriptContext)
+        return CJS_Return(true);
+
+      CXFA_Object* pObject = pScriptContext->GetThisObject();
+      if (!pObject)
+        return CJS_Return(true);
+
+      uint32_t dwFlag = XFA_RESOLVENODE_Children | XFA_RESOLVENODE_Parent |
+                        XFA_RESOLVENODE_Siblings;
+      XFA_RESOLVENODE_RS resolveNodeRS;
+      bool iRet = pScriptContext->ResolveObjects(
+          pObject, runtime->ToWideString(params[0]).AsStringView(),
+          &resolveNodeRS, dwFlag, nullptr);
+      if (!iRet || !resolveNodeRS.objects.front()->IsNode())
+        return CJS_Return(true);
+
+      pNode = resolveNodeRS.objects.front()->AsNode();
+    }
+  }
+  pNotify->SetFocusWidgetNode(pNode);
+  return CJS_Return(true);
+}
+
+CJS_Return CJX_HostPseudoModel::getFocus(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return CJS_Return(true);
+
+  CXFA_Node* pNode = pNotify->GetFocusWidgetNode();
+  if (!pNode)
+    return CJS_Return(true);
+
+  CFXJSE_Value* value =
+      GetDocument()->GetScriptContext()->GetJSValueFromMap(pNode);
+  if (!value)
+    return CJS_Return(runtime->NewNull());
+
+  return CJS_Return(value->DirectGetValue().Get(runtime->GetIsolate()));
+}
+
+CJS_Return CJX_HostPseudoModel::messageBox(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  if (!GetDocument()->GetScriptContext()->IsRunAtClient())
+    return CJS_Return(true);
+
+  if (params.empty() || params.size() > 4)
+    return CJS_Return(JSGetStringFromID(JSMessage::kParamError));
+
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return CJS_Return(true);
+
+  WideString message;
+  if (params.size() >= 1)
+    message = runtime->ToWideString(params[0]);
+
+  WideString title;
+  if (params.size() >= 2)
+    title = runtime->ToWideString(params[1]);
+
+  uint32_t messageType = XFA_MBICON_Error;
+  if (params.size() >= 3) {
+    messageType = runtime->ToInt32(params[2]);
+    if (messageType > XFA_MBICON_Status)
+      messageType = XFA_MBICON_Error;
+  }
+
+  uint32_t buttonType = XFA_MB_OK;
+  if (params.size() >= 4) {
+    buttonType = runtime->ToInt32(params[3]);
+    if (buttonType > XFA_MB_YesNoCancel)
+      buttonType = XFA_MB_OK;
+  }
+
+  int32_t iValue = pNotify->GetAppProvider()->MsgBox(message, title,
+                                                     messageType, buttonType);
+  return CJS_Return(runtime->NewNumber(iValue));
+}
+
+CJS_Return CJX_HostPseudoModel::documentCountInBatch(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  return CJS_Return(runtime->NewNumber(0));
+}
+
+CJS_Return CJX_HostPseudoModel::print(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  if (!GetDocument()->GetScriptContext()->IsRunAtClient())
+    return CJS_Return(true);
+
+  if (params.size() != 8)
+    return CJS_Return(JSGetStringFromID(JSMessage::kParamError));
+
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return CJS_Return(true);
+
+  uint32_t dwOptions = 0;
+  if (runtime->ToBoolean(params[0]))
+    dwOptions |= XFA_PRINTOPT_ShowDialog;
+  if (runtime->ToBoolean(params[3]))
+    dwOptions |= XFA_PRINTOPT_CanCancel;
+  if (runtime->ToBoolean(params[4]))
+    dwOptions |= XFA_PRINTOPT_ShrinkPage;
+  if (runtime->ToBoolean(params[5]))
+    dwOptions |= XFA_PRINTOPT_AsImage;
+  if (runtime->ToBoolean(params[6]))
+    dwOptions |= XFA_PRINTOPT_ReverseOrder;
+  if (runtime->ToBoolean(params[7]))
+    dwOptions |= XFA_PRINTOPT_PrintAnnot;
+
+  int32_t nStartPage = runtime->ToInt32(params[1]);
+  int32_t nEndPage = runtime->ToInt32(params[2]);
+
+  pNotify->GetDocEnvironment()->Print(pNotify->GetHDOC(), nStartPage, nEndPage,
+                                      dwOptions);
+  return CJS_Return(true);
+}
+
+CJS_Return CJX_HostPseudoModel::importData(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  if (params.empty() || params.size() > 1)
+    return CJS_Return(JSGetStringFromID(JSMessage::kParamError));
+
+  return CJS_Return(true);
+}
+
+CJS_Return CJX_HostPseudoModel::exportData(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  if (params.empty() || params.size() > 2)
+    return CJS_Return(JSGetStringFromID(JSMessage::kParamError));
+
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return CJS_Return(true);
+
+  WideString filePath;
+  if (params.size() >= 1)
+    filePath = runtime->ToWideString(params[0]);
+
+  bool XDP = true;
+  if (params.size() >= 2)
+    XDP = runtime->ToBoolean(params[1]);
+
+  pNotify->GetDocEnvironment()->ExportData(pNotify->GetHDOC(), filePath, XDP);
+  return CJS_Return(true);
+}
+
+CJS_Return CJX_HostPseudoModel::pageUp(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return CJS_Return(true);
+
+  CXFA_FFDoc* hDoc = pNotify->GetHDOC();
+  int32_t nCurPage = pNotify->GetDocEnvironment()->GetCurrentPage(hDoc);
+  int32_t nNewPage = 0;
+  if (nCurPage <= 1)
+    return CJS_Return(true);
+
+  nNewPage = nCurPage - 1;
+  pNotify->GetDocEnvironment()->SetCurrentPage(hDoc, nNewPage);
+  return CJS_Return(true);
+}
+
+CJS_Return CJX_HostPseudoModel::pageDown(
+    CJS_V8* runtime,
+    const std::vector<v8::Local<v8::Value>>& params) {
+  CXFA_FFNotify* pNotify = GetDocument()->GetNotify();
+  if (!pNotify)
+    return CJS_Return(true);
+
+  CXFA_FFDoc* hDoc = pNotify->GetHDOC();
+  int32_t nCurPage = pNotify->GetDocEnvironment()->GetCurrentPage(hDoc);
+  int32_t nPageCount = pNotify->GetDocEnvironment()->CountPages(hDoc);
+  if (!nPageCount || nCurPage == nPageCount)
+    return CJS_Return(true);
+
+  int32_t nNewPage = 0;
+  if (nCurPage >= nPageCount)
+    nNewPage = nPageCount - 1;
+  else
+    nNewPage = nCurPage + 1;
+
+  pNotify->GetDocEnvironment()->SetCurrentPage(hDoc, nNewPage);
+  return CJS_Return(true);
+}