Introduce IJS_Runtime::ScopedEventContext helper class.chromium/3451

This proves that m_EventContextArray is, in fact, a stack.
Tidy one function by using AutoRestorer while at it.

Change-Id: I319538b4eadcd9ce83319aa73861635dd5eb8c36
Reviewed-on: https://pdfium-review.googlesource.com/33970
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

3 files changed, 11 insertions, 22 deletions

diff --git a/fpdfsdk/cpdfsdk_actionhandler.cpp b/fpdfsdk/cpdfsdk_actionhandler.cpp
index d7bcd7f350..5b72082104 100644
--- a/fpdfsdk/cpdfsdk_actionhandler.cpp
+++ b/fpdfsdk/cpdfsdk_actionhandler.cpp
@@ -539,12 +539,8 @@ void CPDFSDK_ActionHandler::RunScriptForAction(
 void CPDFSDK_ActionHandler::RunScript(CPDFSDK_FormFillEnvironment* pFormFillEnv,
                                       const WideString& script,
                                       const RunScriptCallback& cb) {
-  IJS_Runtime* pRuntime = pFormFillEnv->GetIJSRuntime();
-  IJS_EventContext* pContext = pRuntime->NewEventContext();
-
-  cb(pContext);
-
+  IJS_Runtime::ScopedEventContext pContext(pFormFillEnv->GetIJSRuntime());
+  cb(pContext.Get());
   pContext->RunScript(script);
-  pRuntime->ReleaseEventContext(pContext);
   // TODO(dsinclair): Return error if RunScript returns a IJS_Runtime::JS_Error.
 }
diff --git a/fpdfsdk/cpdfsdk_interform.cpp b/fpdfsdk/cpdfsdk_interform.cpp
index 638b4dfc07..1d8002a764 100644
--- a/fpdfsdk/cpdfsdk_interform.cpp
+++ b/fpdfsdk/cpdfsdk_interform.cpp
@@ -19,6 +19,7 @@
 #include "core/fpdfapi/parser/cpdf_stream.h"
 #include "core/fpdfdoc/cpdf_actionfields.h"
 #include "core/fpdfdoc/cpdf_interform.h"
+#include "core/fxcrt/autorestorer.h"
 #include "core/fxge/cfx_graphstatedata.h"
 #include "core/fxge/cfx_pathdata.h"
 #include "fpdfsdk/cpdfsdk_actionhandler.h"
@@ -255,12 +256,11 @@ void CPDFSDK_InterForm::OnCalculate(CPDF_FormField* pFormField) {
   if (m_bBusy)
     return;
 
+  AutoRestorer<bool> restorer(&m_bBusy);
   m_bBusy = true;
 
-  if (!IsCalculateEnabled()) {
-    m_bBusy = false;
+  if (!IsCalculateEnabled())
     return;
-  }
 
   IJS_Runtime* pRuntime = m_pFormFillEnv->GetIJSRuntime();
   int nSize = m_pInterForm->CountFieldsInCalculationOrder();
@@ -285,18 +285,16 @@ void CPDFSDK_InterForm::OnCalculate(CPDF_FormField* pFormField) {
     if (csJS.IsEmpty())
       continue;
 
-    IJS_EventContext* pContext = pRuntime->NewEventContext();
     WideString sOldValue = pField->GetValue();
     WideString sValue = sOldValue;
     bool bRC = true;
+    IJS_Runtime::ScopedEventContext pContext(pRuntime);
     pContext->OnField_Calculate(pFormField, pField, sValue, bRC);
 
     Optional<IJS_Runtime::JS_Error> err = pContext->RunScript(csJS);
-    pRuntime->ReleaseEventContext(pContext);
     if (!err && bRC && sValue.Compare(sOldValue) != 0)
       pField->SetValue(sValue, true);
   }
-  m_bBusy = false;
 }
 
 WideString CPDFSDK_InterForm::OnFormat(CPDF_FormField* pFormField,
@@ -325,11 +323,10 @@ WideString CPDFSDK_InterForm::OnFormat(CPDF_FormField* pFormField,
       if (!script.IsEmpty()) {
         WideString Value = sValue;
 
-        IJS_EventContext* pContext = pRuntime->NewEventContext();
+        IJS_Runtime::ScopedEventContext pContext(pRuntime);
         pContext->OnField_Format(pFormField, Value, true);
 
         Optional<IJS_Runtime::JS_Error> err = pContext->RunScript(script);
-        pRuntime->ReleaseEventContext(pContext);
         if (!err) {
           sValue = Value;
           bFormatted = true;
diff --git a/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp b/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp
index f9f5981efb..81e5fd08f4 100644
--- a/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp
+++ b/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp
@@ -994,10 +994,8 @@ bool CPDFXFA_DocEnvironment::SetPropertyInNonXFAGlobalObject(
   if (!pIJSRuntime)
     return false;
 
-  IJS_EventContext* pContext = pIJSRuntime->NewEventContext();
-  bool bRet = pIJSRuntime->SetValueByNameInGlobalObject(szPropName, pValue);
-  pIJSRuntime->ReleaseEventContext(pContext);
-  return bRet;
+  IJS_Runtime::ScopedEventContext pContext(pIJSRuntime);
+  return pIJSRuntime->SetValueByNameInGlobalObject(szPropName, pValue);
 }
 
 bool CPDFXFA_DocEnvironment::GetPropertyFromNonXFAGlobalObject(
@@ -1015,8 +1013,6 @@ bool CPDFXFA_DocEnvironment::GetPropertyFromNonXFAGlobalObject(
   if (!pIJSRuntime)
     return false;
 
-  IJS_EventContext* pContext = pIJSRuntime->NewEventContext();
-  bool bRet = pIJSRuntime->GetValueByNameFromGlobalObject(szPropName, pValue);
-  pIJSRuntime->ReleaseEventContext(pContext);
-  return bRet;
+  IJS_Runtime::ScopedEventContext pContext(pIJSRuntime);
+  return pIJSRuntime->GetValueByNameFromGlobalObject(szPropName, pValue);
 }