Limit XFA FormCalc program translation size.

BUG=chromium:665087,chromium:718492

Change-Id: I09e93b4167ab2c0b3b53641243aa0cbeb5b98c4f
Reviewed-on: https://pdfium-review.googlesource.com/3114
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Nicolás Peña <npm@chromium.org>

8 files changed, 478 insertions, 304 deletions

diff --git a/xfa/fxfa/fm2js/xfa_expression.cpp b/xfa/fxfa/fm2js/xfa_expression.cpp
index c1e451eade..324038f7ed 100644
--- a/xfa/fxfa/fm2js/xfa_expression.cpp
+++ b/xfa/fxfa/fm2js/xfa_expression.cpp
@@ -18,6 +18,11 @@ const wchar_t RUNTIMEBLOCKTEMPARRAY[] =
 const wchar_t RUNTIMEBLOCKTEMPARRAYINDEX[] =
     L"foxit_xfa_formcalc_runtime_block_temp_array_index";
 
+const wchar_t kLessEqual[] = L" <= ";
+const wchar_t kGreaterEqual[] = L" >= ";
+const wchar_t kPlusEqual[] = L" += ";
+const wchar_t kMinusEqual[] = L" -= ";
+
 }  // namespace
 
 CXFA_FMExpression::CXFA_FMExpression(uint32_t line)
@@ -26,9 +31,13 @@ CXFA_FMExpression::CXFA_FMExpression(uint32_t line)
 CXFA_FMExpression::CXFA_FMExpression(uint32_t line, XFA_FM_EXPTYPE type)
     : m_type(type), m_line(line) {}
 
-void CXFA_FMExpression::ToJavaScript(CFX_WideTextBuf& javascript) {}
+bool CXFA_FMExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+  return true;
+}
 
-void CXFA_FMExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {}
+bool CXFA_FMExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+  return true;
+}
 
 CXFA_FMFunctionDefinition::CXFA_FMFunctionDefinition(
     uint32_t line,
@@ -44,10 +53,10 @@ CXFA_FMFunctionDefinition::CXFA_FMFunctionDefinition(
 
 CXFA_FMFunctionDefinition::~CXFA_FMFunctionDefinition() {}
 
-void CXFA_FMFunctionDefinition::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMFunctionDefinition::ToJavaScript(CFX_WideTextBuf& javascript) {
   if (m_isGlobal && m_pExpressions.empty()) {
     javascript << L"// comments only";
-    return;
+    return true;
   }
   if (m_isGlobal) {
     javascript << L"(\n";
@@ -78,10 +87,13 @@ void CXFA_FMFunctionDefinition::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = null;\n";
   for (const auto& expr : m_pExpressions) {
+    bool ret;
     if (expr == m_pExpressions.back())
-      expr->ToImpliedReturnJS(javascript);
+      ret = expr->ToImpliedReturnJS(javascript);
     else
-      expr->ToJavaScript(javascript);
+      ret = expr->ToJavaScript(javascript);
+    if (!ret || CFXA_IsTooBig(javascript))
+      return false;
   }
   javascript << L"return ";
   if (m_isGlobal) {
@@ -96,9 +108,12 @@ void CXFA_FMFunctionDefinition::ToJavaScript(CFX_WideTextBuf& javascript) {
   if (m_isGlobal) {
     javascript << L").call(this);\n";
   }
+  return true;
 }
 
-void CXFA_FMFunctionDefinition::ToImpliedReturnJS(CFX_WideTextBuf&) {}
+bool CXFA_FMFunctionDefinition::ToImpliedReturnJS(CFX_WideTextBuf&) {
+  return true;
+}
 
 CXFA_FMVarExpression::CXFA_FMVarExpression(
     uint32_t line,
@@ -110,7 +125,7 @@ CXFA_FMVarExpression::CXFA_FMVarExpression(
 
 CXFA_FMVarExpression::~CXFA_FMVarExpression() {}
 
-void CXFA_FMVarExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMVarExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L"var ";
   CFX_WideString tempName(m_wsName);
   if (m_wsName.GetAt(0) == L'!') {
@@ -119,7 +134,8 @@ void CXFA_FMVarExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << tempName;
   javascript << L" = ";
   if (m_pInit) {
-    m_pInit->ToJavaScript(javascript);
+    if (!m_pInit->ToJavaScript(javascript))
+      return false;
     javascript << tempName;
     javascript << L" = ";
     javascript << XFA_FM_EXPTypeToString(VARFILTER);
@@ -129,9 +145,10 @@ void CXFA_FMVarExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   } else {
     javascript << L"\"\";\n";
   }
+  return true;
 }
 
-void CXFA_FMVarExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+bool CXFA_FMVarExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << L"var ";
   CFX_WideString tempName(m_wsName);
   if (m_wsName.GetAt(0) == L'!') {
@@ -140,7 +157,8 @@ void CXFA_FMVarExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << tempName;
   javascript << L" = ";
   if (m_pInit) {
-    m_pInit->ToJavaScript(javascript);
+    if (!m_pInit->ToJavaScript(javascript))
+      return false;
     javascript << tempName;
     javascript << L" = ";
     javascript << XFA_FM_EXPTypeToString(VARFILTER);
@@ -154,6 +172,7 @@ void CXFA_FMVarExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << L" = ";
   javascript << tempName;
   javascript << L";\n";
+  return true;
 }
 
 CXFA_FMExpExpression::CXFA_FMExpExpression(
@@ -164,37 +183,38 @@ CXFA_FMExpExpression::CXFA_FMExpExpression(
 
 CXFA_FMExpExpression::~CXFA_FMExpExpression() {}
 
-void CXFA_FMExpExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
-  if (m_pExpression->GetOperatorToken() == TOKassign) {
-    m_pExpression->ToJavaScript(javascript);
-  } else {
-    m_pExpression->ToJavaScript(javascript);
+bool CXFA_FMExpExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+  bool ret = m_pExpression->ToJavaScript(javascript);
+  if (m_pExpression->GetOperatorToken() != TOKassign)
     javascript << L";\n";
-  }
+  return ret;
 }
 
-void CXFA_FMExpExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
-  if (m_pExpression->GetOperatorToken() == TOKassign) {
-    m_pExpression->ToImpliedReturnJS(javascript);
-  } else {
-    if (m_pExpression->GetOperatorToken() == TOKstar ||
-        m_pExpression->GetOperatorToken() == TOKdotstar ||
-        m_pExpression->GetOperatorToken() == TOKdotscream ||
-        m_pExpression->GetOperatorToken() == TOKdotdot ||
-        m_pExpression->GetOperatorToken() == TOKdot) {
-      javascript << RUNTIMEFUNCTIONRETURNVALUE;
-      javascript << L" = ";
-      javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
-      javascript << L"(";
-      m_pExpression->ToJavaScript(javascript);
-      javascript << L");\n";
-    } else {
-      javascript << RUNTIMEFUNCTIONRETURNVALUE;
-      javascript << L" = ";
-      m_pExpression->ToJavaScript(javascript);
-      javascript << L";\n";
-    }
+bool CXFA_FMExpExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+  if (m_pExpression->GetOperatorToken() == TOKassign)
+    return m_pExpression->ToImpliedReturnJS(javascript);
+
+  if (m_pExpression->GetOperatorToken() == TOKstar ||
+      m_pExpression->GetOperatorToken() == TOKdotstar ||
+      m_pExpression->GetOperatorToken() == TOKdotscream ||
+      m_pExpression->GetOperatorToken() == TOKdotdot ||
+      m_pExpression->GetOperatorToken() == TOKdot) {
+    javascript << RUNTIMEFUNCTIONRETURNVALUE;
+    javascript << L" = ";
+    javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
+    javascript << L"(";
+    if (!m_pExpression->ToJavaScript(javascript))
+      return false;
+    javascript << L");\n";
+    return true;
   }
+
+  javascript << RUNTIMEFUNCTIONRETURNVALUE;
+  javascript << L" = ";
+  if (!m_pExpression->ToJavaScript(javascript))
+    return false;
+  javascript << L";\n";
+  return true;
 }
 
 CXFA_FMBlockExpression::CXFA_FMBlockExpression(
@@ -205,22 +225,29 @@ CXFA_FMBlockExpression::CXFA_FMBlockExpression(
 
 CXFA_FMBlockExpression::~CXFA_FMBlockExpression() {}
 
-void CXFA_FMBlockExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMBlockExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L"{\n";
-  for (const auto& expr : m_ExpressionList)
-    expr->ToJavaScript(javascript);
+  for (const auto& expr : m_ExpressionList) {
+    if (!expr->ToJavaScript(javascript) || CFXA_IsTooBig(javascript))
+      return false;
+  }
   javascript << L"}\n";
+  return true;
 }
 
-void CXFA_FMBlockExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+bool CXFA_FMBlockExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << L"{\n";
   for (const auto& expr : m_ExpressionList) {
+    bool ret;
     if (expr == m_ExpressionList.back())
-      expr->ToImpliedReturnJS(javascript);
+      ret = expr->ToImpliedReturnJS(javascript);
     else
-      expr->ToJavaScript(javascript);
+      ret = expr->ToJavaScript(javascript);
+    if (!ret || CFXA_IsTooBig(javascript))
+      return false;
   }
   javascript << L"}\n";
+  return true;
 }
 
 CXFA_FMDoExpression::CXFA_FMDoExpression(
@@ -230,12 +257,12 @@ CXFA_FMDoExpression::CXFA_FMDoExpression(
 
 CXFA_FMDoExpression::~CXFA_FMDoExpression() {}
 
-void CXFA_FMDoExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
-  m_pList->ToJavaScript(javascript);
+bool CXFA_FMDoExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+  return m_pList->ToJavaScript(javascript);
 }
 
-void CXFA_FMDoExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
-  m_pList->ToImpliedReturnJS(javascript);
+bool CXFA_FMDoExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+  return m_pList->ToImpliedReturnJS(javascript);
 }
 
 CXFA_FMIfExpression::CXFA_FMIfExpression(
@@ -250,63 +277,88 @@ CXFA_FMIfExpression::CXFA_FMIfExpression(
 
 CXFA_FMIfExpression::~CXFA_FMIfExpression() {}
 
-void CXFA_FMIfExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMIfExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L"if (";
   if (m_pExpression) {
     javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
     javascript << L"(";
-    m_pExpression->ToJavaScript(javascript);
+    if (!m_pExpression->ToJavaScript(javascript))
+      return false;
     javascript << L")";
   }
   javascript << L")\n";
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
   if (m_pIfExpression) {
-    m_pIfExpression->ToJavaScript(javascript);
+    if (!m_pIfExpression->ToJavaScript(javascript))
+      return false;
+    if (CFXA_IsTooBig(javascript))
+      return false;
   }
+
   if (m_pElseExpression) {
     if (m_pElseExpression->GetExpType() == XFA_FM_EXPTYPE_IF) {
       javascript << L"else\n";
       javascript << L"{\n";
-      m_pElseExpression->ToJavaScript(javascript);
+      if (!m_pElseExpression->ToJavaScript(javascript))
+        return false;
       javascript << L"}\n";
     } else {
       javascript << L"else\n";
-      m_pElseExpression->ToJavaScript(javascript);
+      if (!m_pElseExpression->ToJavaScript(javascript))
+        return false;
     }
   }
+  return !CFXA_IsTooBig(javascript);
 }
 
-void CXFA_FMIfExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+bool CXFA_FMIfExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = 0;\n";
   javascript << L"if (";
   if (m_pExpression) {
     javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
     javascript << L"(";
-    m_pExpression->ToJavaScript(javascript);
+    if (!m_pExpression->ToJavaScript(javascript))
+      return false;
     javascript << L")";
   }
   javascript << L")\n";
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
   if (m_pIfExpression) {
-    m_pIfExpression->ToImpliedReturnJS(javascript);
+    if (!m_pIfExpression->ToImpliedReturnJS(javascript))
+      return false;
+    if (CFXA_IsTooBig(javascript))
+      return false;
   }
   if (m_pElseExpression) {
     if (m_pElseExpression->GetExpType() == XFA_FM_EXPTYPE_IF) {
       javascript << L"else\n";
       javascript << L"{\n";
-      m_pElseExpression->ToImpliedReturnJS(javascript);
+      if (!m_pElseExpression->ToImpliedReturnJS(javascript))
+        return false;
       javascript << L"}\n";
     } else {
       javascript << L"else\n";
-      m_pElseExpression->ToImpliedReturnJS(javascript);
+      if (!m_pElseExpression->ToImpliedReturnJS(javascript))
+        return false;
     }
   }
+  return !CFXA_IsTooBig(javascript);
 }
 
 CXFA_FMLoopExpression::~CXFA_FMLoopExpression() {}
 
-void CXFA_FMLoopExpression::ToJavaScript(CFX_WideTextBuf& javascript) {}
+bool CXFA_FMLoopExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+  return true;
+}
 
-void CXFA_FMLoopExpression::ToImpliedReturnJS(CFX_WideTextBuf&) {}
+bool CXFA_FMLoopExpression::ToImpliedReturnJS(CFX_WideTextBuf&) {
+  return true;
+}
 
 CXFA_FMWhileExpression::CXFA_FMWhileExpression(
     uint32_t line,
@@ -318,20 +370,32 @@ CXFA_FMWhileExpression::CXFA_FMWhileExpression(
 
 CXFA_FMWhileExpression::~CXFA_FMWhileExpression() {}
 
-void CXFA_FMWhileExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMWhileExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L"while (";
-  m_pCondition->ToJavaScript(javascript);
+  if (!m_pCondition->ToJavaScript(javascript))
+    return false;
   javascript << L")\n";
-  m_pExpression->ToJavaScript(javascript);
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
+  if (!m_pExpression->ToJavaScript(javascript))
+    return false;
+  return !CFXA_IsTooBig(javascript);
 }
 
-void CXFA_FMWhileExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+bool CXFA_FMWhileExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = 0;\n";
   javascript << L"while (";
-  m_pCondition->ToJavaScript(javascript);
+  if (!m_pCondition->ToJavaScript(javascript))
+    return false;
   javascript << L")\n";
-  m_pExpression->ToImpliedReturnJS(javascript);
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
+  if (!m_pExpression->ToImpliedReturnJS(javascript))
+    return false;
+  return !CFXA_IsTooBig(javascript);
 }
 
 CXFA_FMBreakExpression::CXFA_FMBreakExpression(uint32_t line)
@@ -339,16 +403,18 @@ CXFA_FMBreakExpression::CXFA_FMBreakExpression(uint32_t line)
 
 CXFA_FMBreakExpression::~CXFA_FMBreakExpression() {}
 
-void CXFA_FMBreakExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMBreakExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = 0;\n";
   javascript << L"break;\n";
+  return true;
 }
 
-void CXFA_FMBreakExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+bool CXFA_FMBreakExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = 0;\n";
   javascript << L"break;\n";
+  return true;
 }
 
 CXFA_FMContinueExpression::CXFA_FMContinueExpression(uint32_t line)
@@ -356,16 +422,18 @@ CXFA_FMContinueExpression::CXFA_FMContinueExpression(uint32_t line)
 
 CXFA_FMContinueExpression::~CXFA_FMContinueExpression() {}
 
-void CXFA_FMContinueExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMContinueExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = 0;\n";
   javascript << L"continue;\n";
+  return true;
 }
 
-void CXFA_FMContinueExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+bool CXFA_FMContinueExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = 0;\n";
   javascript << L"continue;\n";
+  return true;
 }
 
 CXFA_FMForExpression::CXFA_FMForExpression(
@@ -380,13 +448,13 @@ CXFA_FMForExpression::CXFA_FMForExpression(
       m_wsVariant(wsVariant),
       m_pAssignment(std::move(pAssignment)),
       m_pAccessor(std::move(pAccessor)),
-      m_iDirection(iDirection),
+      m_bDirection(iDirection == 1),
       m_pStep(std::move(pStep)),
       m_pList(std::move(pList)) {}
 
 CXFA_FMForExpression::~CXFA_FMForExpression() {}
 
-void CXFA_FMForExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMForExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L"{\nvar ";
   CFX_WideString tempVariant;
   if (m_wsVariant.GetAt(0) == L'!') {
@@ -402,40 +470,43 @@ void CXFA_FMForExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L" = ";
   javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
   javascript << L"(";
-  m_pAssignment->ToJavaScript(javascript);
+  if (!m_pAssignment->ToJavaScript(javascript))
+    return false;
   javascript << L"); ";
   javascript << tempVariant;
-  if (m_iDirection == 1) {
-    javascript << L" <= ";
-    javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
-    javascript << L"(";
-    m_pAccessor->ToJavaScript(javascript);
-    javascript << L"); ";
-    javascript << tempVariant;
-    javascript << L" += ";
-  } else {
-    javascript << L" >= ";
-    javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
-    javascript << L"(";
-    m_pAccessor->ToJavaScript(javascript);
-    javascript << L"); ";
-    javascript << tempVariant;
-    javascript << L" -= ";
-  }
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
+  javascript << (m_bDirection ? kLessEqual : kGreaterEqual);
+  javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
+  javascript << L"(";
+  if (!m_pAccessor->ToJavaScript(javascript))
+    return false;
+  javascript << L"); ";
+  javascript << tempVariant;
+  javascript << (m_bDirection ? kPlusEqual : kMinusEqual);
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
   if (m_pStep) {
     javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
     javascript << L"(";
-    m_pStep->ToJavaScript(javascript);
+    if (!m_pStep->ToJavaScript(javascript))
+      return false;
     javascript << L")";
+    if (CFXA_IsTooBig(javascript))
+      return false;
   } else {
     javascript << L"1";
   }
   javascript << L")\n";
-  m_pList->ToJavaScript(javascript);
+  if (!m_pList->ToJavaScript(javascript))
+    return false;
   javascript << L"}\n";
+  return !CFXA_IsTooBig(javascript);
 }
 
-void CXFA_FMForExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+bool CXFA_FMForExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = 0;\n";
   javascript << L"{\nvar ";
@@ -453,37 +524,41 @@ void CXFA_FMForExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << L" = ";
   javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
   javascript << L"(";
-  m_pAssignment->ToJavaScript(javascript);
+  if (!m_pAssignment->ToJavaScript(javascript))
+    return false;
   javascript << L"); ";
   javascript << tempVariant;
-  if (m_iDirection == 1) {
-    javascript << L" <= ";
-    javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
-    javascript << L"(";
-    m_pAccessor->ToJavaScript(javascript);
-    javascript << L"); ";
-    javascript << tempVariant;
-    javascript << L" += ";
-  } else {
-    javascript << L" >= ";
-    javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
-    javascript << L"(";
-    m_pAccessor->ToJavaScript(javascript);
-    javascript << L"); ";
-    javascript << tempVariant;
-    javascript << L" -= ";
-  }
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
+  javascript << (m_bDirection ? kLessEqual : kGreaterEqual);
+  javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
+  javascript << L"(";
+  if (!m_pAccessor->ToJavaScript(javascript))
+    return false;
+  javascript << L"); ";
+  javascript << tempVariant;
+  javascript << L" += ";
+  javascript << (m_bDirection ? kPlusEqual : kMinusEqual);
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
   if (m_pStep) {
     javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
     javascript << L"(";
-    m_pStep->ToJavaScript(javascript);
+    if (!m_pStep->ToJavaScript(javascript))
+      return false;
     javascript << L")";
+    if (CFXA_IsTooBig(javascript))
+      return false;
   } else {
     javascript << L"1";
   }
   javascript << L")\n";
-  m_pList->ToImpliedReturnJS(javascript);
+  if (!m_pList->ToImpliedReturnJS(javascript))
+    return false;
   javascript << L"}\n";
+  return !CFXA_IsTooBig(javascript);
 }
 
 CXFA_FMForeachExpression::CXFA_FMForeachExpression(
@@ -498,7 +573,7 @@ CXFA_FMForeachExpression::CXFA_FMForeachExpression(
 
 CXFA_FMForeachExpression::~CXFA_FMForeachExpression() {}
 
-void CXFA_FMForeachExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMForeachExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L"{\n";
   javascript << L"var ";
   if (m_wsIdentifier.GetAt(0) == L'!') {
@@ -516,9 +591,12 @@ void CXFA_FMForeachExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L"(";
 
   for (const auto& expr : m_pAccessors) {
-    expr->ToJavaScript(javascript);
+    if (!expr->ToJavaScript(javascript))
+      return false;
     if (expr != m_pAccessors.back())
       javascript << L", ";
+    if (CFXA_IsTooBig(javascript))
+      return false;
   }
   javascript << L");\n";
   javascript << L"var ";
@@ -541,12 +619,14 @@ void CXFA_FMForeachExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L"[";
   javascript << RUNTIMEBLOCKTEMPARRAYINDEX;
   javascript << L"++];\n";
-  m_pList->ToJavaScript(javascript);
+  if (!m_pList->ToJavaScript(javascript))
+    return false;
   javascript << L"}\n";
   javascript << L"}\n";
+  return !CFXA_IsTooBig(javascript);
 }
 
-void CXFA_FMForeachExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+bool CXFA_FMForeachExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = 0;\n";
   javascript << L"{\n";
@@ -565,9 +645,12 @@ void CXFA_FMForeachExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << XFA_FM_EXPTypeToString(CONCATFMOBJECT);
   javascript << L"(";
   for (const auto& expr : m_pAccessors) {
-    expr->ToJavaScript(javascript);
+    if (!expr->ToJavaScript(javascript))
+      return false;
     if (expr != m_pAccessors.back())
       javascript << L", ";
+    if (CFXA_IsTooBig(javascript))
+      return false;
   }
   javascript << L");\n";
   javascript << L"var ";
@@ -590,7 +673,9 @@ void CXFA_FMForeachExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << L"[";
   javascript << RUNTIMEBLOCKTEMPARRAYINDEX;
   javascript << L"++];\n";
-  m_pList->ToImpliedReturnJS(javascript);
+  if (!m_pList->ToImpliedReturnJS(javascript))
+    return false;
   javascript << L"}\n";
   javascript << L"}\n";
+  return !CFXA_IsTooBig(javascript);
 }
diff --git a/xfa/fxfa/fm2js/xfa_expression.h b/xfa/fxfa/fm2js/xfa_expression.h
index 9177c305d2..e6022b3e69 100644
--- a/xfa/fxfa/fm2js/xfa_expression.h
+++ b/xfa/fxfa/fm2js/xfa_expression.h
@@ -28,8 +28,8 @@ class CXFA_FMExpression {
   explicit CXFA_FMExpression(uint32_t line);
   CXFA_FMExpression(uint32_t line, XFA_FM_EXPTYPE type);
   virtual ~CXFA_FMExpression() {}
-  virtual void ToJavaScript(CFX_WideTextBuf& javascript);
-  virtual void ToImpliedReturnJS(CFX_WideTextBuf&);
+  virtual bool ToJavaScript(CFX_WideTextBuf& javascript);
+  virtual bool ToImpliedReturnJS(CFX_WideTextBuf&);
   uint32_t GetLine() { return m_line; }
   XFA_FM_EXPTYPE GetExpType() const { return m_type; }
 
@@ -49,8 +49,8 @@ class CXFA_FMFunctionDefinition : public CXFA_FMExpression {
       std::vector<std::unique_ptr<CXFA_FMExpression>>&& expressions);
   ~CXFA_FMFunctionDefinition() override;
 
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf&) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf&) override;
 
  private:
   CFX_WideStringC m_wsName;
@@ -66,8 +66,8 @@ class CXFA_FMVarExpression : public CXFA_FMExpression {
                        std::unique_ptr<CXFA_FMExpression> pInit);
   ~CXFA_FMVarExpression() override;
 
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf&) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf&) override;
 
  private:
   CFX_WideStringC m_wsName;
@@ -80,8 +80,8 @@ class CXFA_FMExpExpression : public CXFA_FMExpression {
                        std::unique_ptr<CXFA_FMSimpleExpression> pExpression);
   ~CXFA_FMExpExpression() override;
 
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf&) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf&) override;
 
  private:
   std::unique_ptr<CXFA_FMSimpleExpression> m_pExpression;
@@ -94,8 +94,8 @@ class CXFA_FMBlockExpression : public CXFA_FMExpression {
       std::vector<std::unique_ptr<CXFA_FMExpression>>&& pExpressionList);
   ~CXFA_FMBlockExpression() override;
 
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf&) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf&) override;
 
  private:
   std::vector<std::unique_ptr<CXFA_FMExpression>> m_ExpressionList;
@@ -106,8 +106,8 @@ class CXFA_FMDoExpression : public CXFA_FMExpression {
   CXFA_FMDoExpression(uint32_t line, std::unique_ptr<CXFA_FMExpression> pList);
   ~CXFA_FMDoExpression() override;
 
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf&) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf&) override;
 
  private:
   std::unique_ptr<CXFA_FMExpression> m_pList;
@@ -121,8 +121,8 @@ class CXFA_FMIfExpression : public CXFA_FMExpression {
                       std::unique_ptr<CXFA_FMExpression> pElseExpression);
   ~CXFA_FMIfExpression() override;
 
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf&) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf&) override;
 
  private:
   std::unique_ptr<CXFA_FMSimpleExpression> m_pExpression;
@@ -134,8 +134,8 @@ class CXFA_FMLoopExpression : public CXFA_FMExpression {
  public:
   explicit CXFA_FMLoopExpression(uint32_t line) : CXFA_FMExpression(line) {}
   ~CXFA_FMLoopExpression() override;
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf&) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf&) override;
 };
 
 class CXFA_FMWhileExpression : public CXFA_FMLoopExpression {
@@ -145,8 +145,8 @@ class CXFA_FMWhileExpression : public CXFA_FMLoopExpression {
                          std::unique_ptr<CXFA_FMExpression> pExpression);
   ~CXFA_FMWhileExpression() override;
 
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf&) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf&) override;
 
  private:
   std::unique_ptr<CXFA_FMSimpleExpression> m_pCondition;
@@ -157,16 +157,16 @@ class CXFA_FMBreakExpression : public CXFA_FMExpression {
  public:
   explicit CXFA_FMBreakExpression(uint32_t line);
   ~CXFA_FMBreakExpression() override;
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf&) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf&) override;
 };
 
 class CXFA_FMContinueExpression : public CXFA_FMExpression {
  public:
   explicit CXFA_FMContinueExpression(uint32_t line);
   ~CXFA_FMContinueExpression() override;
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf&) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf&) override;
 };
 
 class CXFA_FMForExpression : public CXFA_FMLoopExpression {
@@ -180,14 +180,14 @@ class CXFA_FMForExpression : public CXFA_FMLoopExpression {
                        std::unique_ptr<CXFA_FMExpression> pList);
   ~CXFA_FMForExpression() override;
 
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf&) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf&) override;
 
  private:
   CFX_WideStringC m_wsVariant;
   std::unique_ptr<CXFA_FMSimpleExpression> m_pAssignment;
   std::unique_ptr<CXFA_FMSimpleExpression> m_pAccessor;
-  int32_t m_iDirection;
+  const bool m_bDirection;
   std::unique_ptr<CXFA_FMSimpleExpression> m_pStep;
   std::unique_ptr<CXFA_FMExpression> m_pList;
 };
@@ -202,8 +202,8 @@ class CXFA_FMForeachExpression : public CXFA_FMLoopExpression {
       std::unique_ptr<CXFA_FMExpression> pList);
   ~CXFA_FMForeachExpression() override;
 
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf&) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf&) override;
 
  private:
   CFX_WideStringC m_wsIdentifier;
diff --git a/xfa/fxfa/fm2js/xfa_fm2jscontext.cpp b/xfa/fxfa/fm2js/xfa_fm2jscontext.cpp
index 8879b94373..716e378ed7 100644
--- a/xfa/fxfa/fm2js/xfa_fm2jscontext.cpp
+++ b/xfa/fxfa/fm2js/xfa_fm2jscontext.cpp
@@ -6123,8 +6123,7 @@ int32_t CXFA_FM2JSContext::Translate(const CFX_WideStringC& wsFormcalc,
   if (status)
     return status;
 
-  program.TranslateProgram(*wsJavascript);
-  return 0;
+  return program.TranslateProgram(*wsJavascript);
 }
 
 CXFA_FM2JSContext::CXFA_FM2JSContext(v8::Isolate* pScriptIsolate,
diff --git a/xfa/fxfa/fm2js/xfa_fmparse.cpp b/xfa/fxfa/fm2js/xfa_fmparse.cpp
index 298a2eb334..a7ba901c89 100644
--- a/xfa/fxfa/fm2js/xfa_fmparse.cpp
+++ b/xfa/fxfa/fm2js/xfa_fmparse.cpp
@@ -29,9 +29,9 @@ CXFA_FMParse::~CXFA_FMParse() {}
 void CXFA_FMParse::NextToken() {
   m_pToken = m_lexer->NextToken();
   while (m_pToken->m_type == TOKreserver) {
-    if (m_lexer->HasError()) {
+    if (m_lexer->HasError())
       break;
-    }
+
     m_pToken = m_lexer->NextToken();
   }
 }
@@ -64,21 +64,10 @@ CXFA_FMParse::ParseTopExpression() {
       return expressions;
     }
 
-    if (m_pToken->m_type == TOKfunc) {
-      expr = ParseFunction();
-      if (expr) {
-        expressions.push_back(std::move(expr));
-      } else {
-        break;
-      }
-    } else {
-      expr = ParseExpression();
-      if (expr) {
-        expressions.push_back(std::move(expr));
-      } else {
-        break;
-      }
-    }
+    expr = m_pToken->m_type == TOKfunc ? ParseFunction() : ParseExpression();
+    if (!expr)
+      break;
+    expressions.push_back(std::move(expr));
   }
   return expressions;
 }
@@ -108,20 +97,18 @@ std::unique_ptr<CXFA_FMExpression> CXFA_FMParse::ParseFunction() {
         if (m_pToken->m_type == TOKcomma) {
           NextToken();
           continue;
-        } else if (m_pToken->m_type == TOKrparen) {
+        }
+        if (m_pToken->m_type == TOKrparen)
           NextToken();
-          break;
-        } else {
+        else
           Check(TOKrparen);
-          break;
-        }
       } else {
         CFX_WideString ws_TempString(m_pToken->m_wstring);
         Error(m_pToken->m_uLinenum, kFMErrExpectedIdentifier,
               ws_TempString.c_str());
         NextToken();
-        break;
       }
+      break;
     }
   }
   Check(TOKdo);
@@ -131,7 +118,7 @@ std::unique_ptr<CXFA_FMExpression> CXFA_FMParse::ParseFunction() {
     expressions = ParseTopExpression();
     Check(TOKendfunc);
   }
-  if (!m_pErrorInfo->message.IsEmpty())
+  if (HasError())
     return nullptr;
 
   return pdfium::MakeUnique<CXFA_FMFunctionDefinition>(
@@ -205,7 +192,7 @@ std::unique_ptr<CXFA_FMExpression> CXFA_FMParse::ParseVarExpression() {
     NextToken();
     expr = ParseExpExpression();
   }
-  if (!m_pErrorInfo->message.IsEmpty())
+  if (HasError())
     return nullptr;
 
   return pdfium::MakeUnique<CXFA_FMVarExpression>(line, ident, std::move(expr));
@@ -233,7 +220,7 @@ std::unique_ptr<CXFA_FMSimpleExpression> CXFA_FMParse::ParseSimpleExpression() {
 std::unique_ptr<CXFA_FMExpression> CXFA_FMParse::ParseExpExpression() {
   uint32_t line = m_pToken->m_uLinenum;
   std::unique_ptr<CXFA_FMSimpleExpression> pExp1 = ParseSimpleExpression();
-  if (!m_pErrorInfo->message.IsEmpty())
+  if (HasError())
     return nullptr;
 
   return pdfium::MakeUnique<CXFA_FMExpExpression>(line, std::move(pExp1));
@@ -522,7 +509,8 @@ CXFA_FMParse::ParsePrimaryExpression() {
         expr =
             pdfium::MakeUnique<CXFA_FMIdentifierExpression>(line, wsIdentifier);
       }
-    } break;
+      break;
+    }
     case TOKif:
       expr = pdfium::MakeUnique<CXFA_FMIdentifierExpression>(
           line, m_pToken->m_wstring);
@@ -543,7 +531,7 @@ CXFA_FMParse::ParsePrimaryExpression() {
       break;
   }
   expr = ParsePostExpression(std::move(expr));
-  if (!m_pErrorInfo->message.IsEmpty())
+  if (HasError())
     expr.reset();
   return expr;
 }
@@ -591,7 +579,8 @@ std::unique_ptr<CXFA_FMSimpleExpression> CXFA_FMParse::ParsePostExpression(
         } else {
           expr.reset();
         }
-      } break;
+        break;
+      }
       case TOKdot:
         NextToken();
         if (m_pToken->m_type == TOKidentifier) {
@@ -645,7 +634,7 @@ std::unique_ptr<CXFA_FMSimpleExpression> CXFA_FMParse::ParsePostExpression(
             }
           } else if (m_pToken->m_type == TOKlbracket) {
             std::unique_ptr<CXFA_FMSimpleExpression> s = ParseIndexExpression();
-            if (!(m_pErrorInfo->message.IsEmpty()))
+            if (HasError())
               return nullptr;
 
             expr = pdfium::MakeUnique<CXFA_FMDotAccessorExpression>(
@@ -673,9 +662,9 @@ std::unique_ptr<CXFA_FMSimpleExpression> CXFA_FMParse::ParsePostExpression(
           NextToken();
           if (m_pToken->m_type == TOKlbracket) {
             std::unique_ptr<CXFA_FMSimpleExpression> s = ParseIndexExpression();
-            if (!(m_pErrorInfo->message.IsEmpty())) {
+            if (HasError())
               return nullptr;
-            }
+
             expr = pdfium::MakeUnique<CXFA_FMDotDotAccessorExpression>(
                 tempLine, std::move(expr), TOKdotdot, tempStr, std::move(s));
           } else {
@@ -693,41 +682,41 @@ std::unique_ptr<CXFA_FMSimpleExpression> CXFA_FMParse::ParsePostExpression(
           return expr;
         }
         break;
-      case TOKdotscream:
+      case TOKdotscream: {
         NextToken();
-        if (m_pToken->m_type == TOKidentifier) {
-          CFX_WideStringC tempStr = m_pToken->m_wstring;
-          uint32_t tempLine = m_pToken->m_uLinenum;
-          NextToken();
-          if (m_pToken->m_type == TOKlbracket) {
-            std::unique_ptr<CXFA_FMSimpleExpression> s = ParseIndexExpression();
-            if (!(m_pErrorInfo->message.IsEmpty()))
-              return nullptr;
-
-            expr = pdfium::MakeUnique<CXFA_FMDotAccessorExpression>(
-                tempLine, std::move(expr), TOKdotscream, tempStr, std::move(s));
-          } else {
-            std::unique_ptr<CXFA_FMSimpleExpression> s =
-                pdfium::MakeUnique<CXFA_FMIndexExpression>(
-                    tempLine, ACCESSOR_NO_INDEX, nullptr, false);
-            expr = pdfium::MakeUnique<CXFA_FMDotAccessorExpression>(
-                line, std::move(expr), TOKdotscream, tempStr, std::move(s));
-            continue;
-          }
-        } else {
+        if (m_pToken->m_type != TOKidentifier) {
           CFX_WideString ws_TempString(m_pToken->m_wstring);
           Error(m_pToken->m_uLinenum, kFMErrExpectedIdentifier,
                 ws_TempString.c_str());
           return expr;
         }
+        CFX_WideStringC tempStr = m_pToken->m_wstring;
+        uint32_t tempLine = m_pToken->m_uLinenum;
+        NextToken();
+        if (m_pToken->m_type != TOKlbracket) {
+          std::unique_ptr<CXFA_FMSimpleExpression> s =
+              pdfium::MakeUnique<CXFA_FMIndexExpression>(
+                  tempLine, ACCESSOR_NO_INDEX, nullptr, false);
+          expr = pdfium::MakeUnique<CXFA_FMDotAccessorExpression>(
+              line, std::move(expr), TOKdotscream, tempStr, std::move(s));
+          continue;
+        }
+        std::unique_ptr<CXFA_FMSimpleExpression> s = ParseIndexExpression();
+        if (HasError())
+          return nullptr;
+
+        expr = pdfium::MakeUnique<CXFA_FMDotAccessorExpression>(
+            tempLine, std::move(expr), TOKdotscream, tempStr, std::move(s));
         break;
+      }
       case TOKdotstar: {
         std::unique_ptr<CXFA_FMSimpleExpression> s =
             pdfium::MakeUnique<CXFA_FMIndexExpression>(line, ACCESSOR_NO_INDEX,
                                                        nullptr, false);
         expr = pdfium::MakeUnique<CXFA_FMDotAccessorExpression>(
             line, std::move(expr), TOKdotstar, L"*", std::move(s));
-      } break;
+        break;
+      }
       default:
         return expr;
     }
@@ -1028,8 +1017,12 @@ std::unique_ptr<CXFA_FMExpression> CXFA_FMParse::ParseDoExpression() {
   NextToken();
   std::unique_ptr<CXFA_FMExpression> expr = ParseBlockExpression();
   Check(TOKend);
-  if (!m_pErrorInfo->message.IsEmpty())
+  if (HasError())
     return nullptr;
 
   return pdfium::MakeUnique<CXFA_FMDoExpression>(line, std::move(expr));
 }
+
+bool CXFA_FMParse::HasError() const {
+  return !m_pErrorInfo->message.IsEmpty();
+}
diff --git a/xfa/fxfa/fm2js/xfa_fmparse.h b/xfa/fxfa/fm2js/xfa_fmparse.h
index ccb793ae68..23b01b877c 100644
--- a/xfa/fxfa/fm2js/xfa_fmparse.h
+++ b/xfa/fxfa/fm2js/xfa_fmparse.h
@@ -48,6 +48,8 @@ class CXFA_FMParse {
   std::unique_ptr<CXFA_FMSimpleExpression> ParseIndexExpression();
 
  private:
+  bool HasError() const;
+
   std::unique_ptr<CXFA_FMLexer> m_lexer;
   CXFA_FMToken* m_pToken;
   CXFA_FMErrorInfo* const m_pErrorInfo;
diff --git a/xfa/fxfa/fm2js/xfa_program.cpp b/xfa/fxfa/fm2js/xfa_program.cpp
index 514b7a6a23..6afe332629 100644
--- a/xfa/fxfa/fm2js/xfa_program.cpp
+++ b/xfa/fxfa/fm2js/xfa_program.cpp
@@ -33,7 +33,8 @@ int32_t CXFA_FMProgram::ParseProgram() {
 }
 
 int32_t CXFA_FMProgram::TranslateProgram(CFX_WideTextBuf& wsJavaScript) {
-  m_globalFunction->ToJavaScript(wsJavaScript);
+  if (!m_globalFunction->ToJavaScript(wsJavaScript))
+    return -1;
   wsJavaScript.AppendChar(0);
   return 0;
 }
diff --git a/xfa/fxfa/fm2js/xfa_simpleexpression.cpp b/xfa/fxfa/fm2js/xfa_simpleexpression.cpp
index fabdaa60f0..1438ff29a4 100644
--- a/xfa/fxfa/fm2js/xfa_simpleexpression.cpp
+++ b/xfa/fxfa/fm2js/xfa_simpleexpression.cpp
@@ -120,9 +120,13 @@ CFX_WideStringC XFA_FM_EXPTypeToString(
 CXFA_FMSimpleExpression::CXFA_FMSimpleExpression(uint32_t line, XFA_FM_TOKEN op)
     : m_line(line), m_op(op) {}
 
-void CXFA_FMSimpleExpression::ToJavaScript(CFX_WideTextBuf& javascript) {}
+bool CXFA_FMSimpleExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+  return true;
+}
 
-void CXFA_FMSimpleExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {}
+bool CXFA_FMSimpleExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+  return true;
+}
 
 XFA_FM_TOKEN CXFA_FMSimpleExpression::GetOperatorToken() const {
   return m_op;
@@ -131,8 +135,9 @@ XFA_FM_TOKEN CXFA_FMSimpleExpression::GetOperatorToken() const {
 CXFA_FMNullExpression::CXFA_FMNullExpression(uint32_t line)
     : CXFA_FMSimpleExpression(line, TOKnull) {}
 
-void CXFA_FMNullExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMNullExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L"null";
+  return true;
 }
 
 CXFA_FMNumberExpression::CXFA_FMNumberExpression(uint32_t line,
@@ -141,8 +146,9 @@ CXFA_FMNumberExpression::CXFA_FMNumberExpression(uint32_t line,
 
 CXFA_FMNumberExpression::~CXFA_FMNumberExpression() {}
 
-void CXFA_FMNumberExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMNumberExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << m_wsNumber;
+  return true;
 }
 
 CXFA_FMStringExpression::CXFA_FMStringExpression(uint32_t line,
@@ -151,11 +157,11 @@ CXFA_FMStringExpression::CXFA_FMStringExpression(uint32_t line,
 
 CXFA_FMStringExpression::~CXFA_FMStringExpression() {}
 
-void CXFA_FMStringExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMStringExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CFX_WideString tempStr(m_wsString);
   if (tempStr.GetLength() <= 2) {
     javascript << tempStr;
-    return;
+    return true;
   }
   javascript.AppendChar(L'\"');
   for (int32_t i = 1; i < tempStr.GetLength() - 1; i++) {
@@ -176,6 +182,7 @@ void CXFA_FMStringExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
     }
   }
   javascript.AppendChar(L'\"');
+  return true;
 }
 
 CXFA_FMIdentifierExpression::CXFA_FMIdentifierExpression(
@@ -186,7 +193,7 @@ CXFA_FMIdentifierExpression::CXFA_FMIdentifierExpression(
 
 CXFA_FMIdentifierExpression::~CXFA_FMIdentifierExpression() {}
 
-void CXFA_FMIdentifierExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMIdentifierExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CFX_WideString tempStr(m_wsIdentifier);
   if (tempStr == L"$") {
     tempStr = L"this";
@@ -208,6 +215,7 @@ void CXFA_FMIdentifierExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
     tempStr = EXCLAMATION_IN_IDENTIFIER + tempStr.Mid(1);
   }
   javascript << tempStr;
+  return true;
 }
 
 CXFA_FMUnaryExpression::CXFA_FMUnaryExpression(
@@ -218,7 +226,9 @@ CXFA_FMUnaryExpression::CXFA_FMUnaryExpression(
 
 CXFA_FMUnaryExpression::~CXFA_FMUnaryExpression() {}
 
-void CXFA_FMUnaryExpression::ToJavaScript(CFX_WideTextBuf& javascript) {}
+bool CXFA_FMUnaryExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+  return true;
+}
 
 CXFA_FMBinExpression::CXFA_FMBinExpression(
     uint32_t line,
@@ -231,7 +241,9 @@ CXFA_FMBinExpression::CXFA_FMBinExpression(
 
 CXFA_FMBinExpression::~CXFA_FMBinExpression() {}
 
-void CXFA_FMBinExpression::ToJavaScript(CFX_WideTextBuf& javascript) {}
+bool CXFA_FMBinExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+  return true;
+}
 
 CXFA_FMAssignExpression::CXFA_FMAssignExpression(
     uint32_t line,
@@ -240,20 +252,27 @@ CXFA_FMAssignExpression::CXFA_FMAssignExpression(
     std::unique_ptr<CXFA_FMSimpleExpression> pExp2)
     : CXFA_FMBinExpression(line, op, std::move(pExp1), std::move(pExp2)) {}
 
-void CXFA_FMAssignExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMAssignExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L"if (";
   javascript << gs_lpStrExpFuncName[ISFMOBJECT];
   javascript << L"(";
-  m_pExp1->ToJavaScript(javascript);
+  CFX_WideTextBuf tempExp1;
+  if (!m_pExp1->ToJavaScript(tempExp1))
+    return false;
+  javascript << tempExp1;
   javascript << L"))\n{\n";
   javascript << gs_lpStrExpFuncName[ASSIGN];
   javascript << L"(";
-  m_pExp1->ToJavaScript(javascript);
+  javascript << tempExp1;
   javascript << L", ";
-  m_pExp2->ToJavaScript(javascript);
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
+  CFX_WideTextBuf tempExp2;
+  if (!m_pExp2->ToJavaScript(tempExp2))
+    return false;
+  javascript << tempExp2;
   javascript << L");\n}\n";
-  CFX_WideTextBuf tempExp1;
-  m_pExp1->ToJavaScript(tempExp1);
   if (m_pExp1->GetOperatorToken() == TOKidentifier &&
       tempExp1.AsStringC() != L"this") {
     javascript << L"else\n{\n";
@@ -261,29 +280,37 @@ void CXFA_FMAssignExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
     javascript << L" = ";
     javascript << gs_lpStrExpFuncName[ASSIGN];
     javascript << L"(";
-    m_pExp1->ToJavaScript(javascript);
+    javascript << tempExp1;
     javascript << L", ";
-    m_pExp2->ToJavaScript(javascript);
+    javascript << tempExp2;
     javascript << L");\n}\n";
   }
+  return !CFXA_IsTooBig(javascript);
 }
 
-void CXFA_FMAssignExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
+bool CXFA_FMAssignExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << L"if (";
   javascript << gs_lpStrExpFuncName[ISFMOBJECT];
   javascript << L"(";
-  m_pExp1->ToJavaScript(javascript);
+  CFX_WideTextBuf tempExp1;
+  if (!m_pExp1->ToJavaScript(tempExp1))
+    return false;
+  javascript << tempExp1;
   javascript << L"))\n{\n";
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = ";
   javascript << gs_lpStrExpFuncName[ASSIGN];
   javascript << L"(";
-  m_pExp1->ToJavaScript(javascript);
+  javascript << tempExp1;
   javascript << L", ";
-  m_pExp2->ToJavaScript(javascript);
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
+  CFX_WideTextBuf tempExp2;
+  if (!m_pExp2->ToJavaScript(tempExp2))
+    return false;
+  javascript << tempExp2;
   javascript << L");\n}\n";
-  CFX_WideTextBuf tempExp1;
-  m_pExp1->ToJavaScript(tempExp1);
   if (m_pExp1->GetOperatorToken() == TOKidentifier &&
       tempExp1.AsStringC() != L"this") {
     javascript << L"else\n{\n";
@@ -293,11 +320,12 @@ void CXFA_FMAssignExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
     javascript << L" = ";
     javascript << gs_lpStrExpFuncName[ASSIGN];
     javascript << L"(";
-    m_pExp1->ToJavaScript(javascript);
+    javascript << tempExp1;
     javascript << L", ";
-    m_pExp2->ToJavaScript(javascript);
+    javascript << tempExp2;
     javascript << L");\n}\n";
   }
+  return !CFXA_IsTooBig(javascript);
 }
 
 CXFA_FMLogicalOrExpression::CXFA_FMLogicalOrExpression(
@@ -307,13 +335,16 @@ CXFA_FMLogicalOrExpression::CXFA_FMLogicalOrExpression(
     std::unique_ptr<CXFA_FMSimpleExpression> pExp2)
     : CXFA_FMBinExpression(line, op, std::move(pExp1), std::move(pExp2)) {}
 
-void CXFA_FMLogicalOrExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMLogicalOrExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << gs_lpStrExpFuncName[LOGICALOR];
   javascript << L"(";
-  m_pExp1->ToJavaScript(javascript);
+  if (!m_pExp1->ToJavaScript(javascript))
+    return false;
   javascript << L", ";
-  m_pExp2->ToJavaScript(javascript);
+  if (!m_pExp2->ToJavaScript(javascript))
+    return false;
   javascript << L")";
+  return !CFXA_IsTooBig(javascript);
 }
 
 CXFA_FMLogicalAndExpression::CXFA_FMLogicalAndExpression(
@@ -323,13 +354,16 @@ CXFA_FMLogicalAndExpression::CXFA_FMLogicalAndExpression(
     std::unique_ptr<CXFA_FMSimpleExpression> pExp2)
     : CXFA_FMBinExpression(line, op, std::move(pExp1), std::move(pExp2)) {}
 
-void CXFA_FMLogicalAndExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMLogicalAndExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << gs_lpStrExpFuncName[LOGICALAND];
   javascript << L"(";
-  m_pExp1->ToJavaScript(javascript);
+  if (!m_pExp1->ToJavaScript(javascript))
+    return false;
   javascript << L", ";
-  m_pExp2->ToJavaScript(javascript);
+  if (!m_pExp2->ToJavaScript(javascript))
+    return false;
   javascript << L")";
+  return !CFXA_IsTooBig(javascript);
 }
 
 CXFA_FMEqualityExpression::CXFA_FMEqualityExpression(
@@ -339,7 +373,7 @@ CXFA_FMEqualityExpression::CXFA_FMEqualityExpression(
     std::unique_ptr<CXFA_FMSimpleExpression> pExp2)
     : CXFA_FMBinExpression(line, op, std::move(pExp1), std::move(pExp2)) {}
 
-void CXFA_FMEqualityExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMEqualityExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   switch (m_op) {
     case TOKeq:
     case TOKkseq:
@@ -354,10 +388,13 @@ void CXFA_FMEqualityExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
       break;
   }
   javascript << L"(";
-  m_pExp1->ToJavaScript(javascript);
+  if (!m_pExp1->ToJavaScript(javascript))
+    return false;
   javascript << L", ";
-  m_pExp2->ToJavaScript(javascript);
+  if (!m_pExp2->ToJavaScript(javascript))
+    return false;
   javascript << L")";
+  return !CFXA_IsTooBig(javascript);
 }
 
 CXFA_FMRelationalExpression::CXFA_FMRelationalExpression(
@@ -367,7 +404,7 @@ CXFA_FMRelationalExpression::CXFA_FMRelationalExpression(
     std::unique_ptr<CXFA_FMSimpleExpression> pExp2)
     : CXFA_FMBinExpression(line, op, std::move(pExp1), std::move(pExp2)) {}
 
-void CXFA_FMRelationalExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMRelationalExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   switch (m_op) {
     case TOKlt:
     case TOKkslt:
@@ -390,10 +427,13 @@ void CXFA_FMRelationalExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
       break;
   }
   javascript << L"(";
-  m_pExp1->ToJavaScript(javascript);
+  if (!m_pExp1->ToJavaScript(javascript))
+    return false;
   javascript << L", ";
-  m_pExp2->ToJavaScript(javascript);
+  if (!m_pExp2->ToJavaScript(javascript))
+    return false;
   javascript << L")";
+  return !CFXA_IsTooBig(javascript);
 }
 
 CXFA_FMAdditiveExpression::CXFA_FMAdditiveExpression(
@@ -403,7 +443,7 @@ CXFA_FMAdditiveExpression::CXFA_FMAdditiveExpression(
     std::unique_ptr<CXFA_FMSimpleExpression> pExp2)
     : CXFA_FMBinExpression(line, op, std::move(pExp1), std::move(pExp2)) {}
 
-void CXFA_FMAdditiveExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMAdditiveExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   switch (m_op) {
     case TOKplus:
       javascript << gs_lpStrExpFuncName[PLUS];
@@ -416,10 +456,13 @@ void CXFA_FMAdditiveExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
       break;
   }
   javascript << L"(";
-  m_pExp1->ToJavaScript(javascript);
+  if (!m_pExp1->ToJavaScript(javascript))
+    return false;
   javascript << L", ";
-  m_pExp2->ToJavaScript(javascript);
+  if (!m_pExp2->ToJavaScript(javascript))
+    return false;
   javascript << L")";
+  return !CFXA_IsTooBig(javascript);
 }
 
 CXFA_FMMultiplicativeExpression::CXFA_FMMultiplicativeExpression(
@@ -429,7 +472,7 @@ CXFA_FMMultiplicativeExpression::CXFA_FMMultiplicativeExpression(
     std::unique_ptr<CXFA_FMSimpleExpression> pExp2)
     : CXFA_FMBinExpression(line, op, std::move(pExp1), std::move(pExp2)) {}
 
-void CXFA_FMMultiplicativeExpression::ToJavaScript(
+bool CXFA_FMMultiplicativeExpression::ToJavaScript(
     CFX_WideTextBuf& javascript) {
   switch (m_op) {
     case TOKmul:
@@ -443,10 +486,13 @@ void CXFA_FMMultiplicativeExpression::ToJavaScript(
       break;
   }
   javascript << L"(";
-  m_pExp1->ToJavaScript(javascript);
+  if (!m_pExp1->ToJavaScript(javascript))
+    return false;
   javascript << L", ";
-  m_pExp2->ToJavaScript(javascript);
+  if (!m_pExp2->ToJavaScript(javascript))
+    return false;
   javascript << L")";
+  return !CFXA_IsTooBig(javascript);
 }
 
 CXFA_FMPosExpression::CXFA_FMPosExpression(
@@ -454,11 +500,13 @@ CXFA_FMPosExpression::CXFA_FMPosExpression(
     std::unique_ptr<CXFA_FMSimpleExpression> pExp)
     : CXFA_FMUnaryExpression(line, TOKplus, std::move(pExp)) {}
 
-void CXFA_FMPosExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMPosExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << gs_lpStrExpFuncName[POSITIVE];
   javascript << L"(";
-  m_pExp->ToJavaScript(javascript);
+  if (!m_pExp->ToJavaScript(javascript))
+    return false;
   javascript << L")";
+  return true;
 }
 
 CXFA_FMNegExpression::CXFA_FMNegExpression(
@@ -466,11 +514,13 @@ CXFA_FMNegExpression::CXFA_FMNegExpression(
     std::unique_ptr<CXFA_FMSimpleExpression> pExp)
     : CXFA_FMUnaryExpression(line, TOKminus, std::move(pExp)) {}
 
-void CXFA_FMNegExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMNegExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << gs_lpStrExpFuncName[NEGATIVE];
   javascript << L"(";
-  m_pExp->ToJavaScript(javascript);
+  if (!m_pExp->ToJavaScript(javascript))
+    return false;
   javascript << L")";
+  return true;
 }
 
 CXFA_FMNotExpression::CXFA_FMNotExpression(
@@ -478,11 +528,13 @@ CXFA_FMNotExpression::CXFA_FMNotExpression(
     std::unique_ptr<CXFA_FMSimpleExpression> pExp)
     : CXFA_FMUnaryExpression(line, TOKksnot, std::move(pExp)) {}
 
-void CXFA_FMNotExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMNotExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << gs_lpStrExpFuncName[NOT];
   javascript << L"(";
-  m_pExp->ToJavaScript(javascript);
+  if (!m_pExp->ToJavaScript(javascript))
+    return false;
   javascript << L")";
+  return true;
 }
 
 CXFA_FMCallExpression::CXFA_FMCallExpression(
@@ -535,9 +587,10 @@ uint32_t CXFA_FMCallExpression::IsMethodWithObjParam(
   return parameters;
 }
 
-void CXFA_FMCallExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMCallExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CFX_WideTextBuf funcName;
-  m_pExp->ToJavaScript(funcName);
+  if (!m_pExp->ToJavaScript(funcName))
+    return false;
   if (m_bIsSomMethod) {
     javascript << funcName;
     javascript << L"(";
@@ -554,20 +607,26 @@ void CXFA_FMCallExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
         }
         javascript << L"(";
         const auto& expr = m_Arguments[i];
-        expr->ToJavaScript(javascript);
+        if (!expr->ToJavaScript(javascript))
+          return false;
         javascript << L")";
         if (i + 1 < m_Arguments.size()) {
           javascript << L", ";
         }
+        if (CFXA_IsTooBig(javascript))
+          return false;
       }
     } else {
       for (const auto& expr : m_Arguments) {
         javascript << gs_lpStrExpFuncName[GETFMVALUE];
         javascript << L"(";
-        expr->ToJavaScript(javascript);
+        if (!expr->ToJavaScript(javascript))
+          return false;
         javascript << L")";
         if (expr != m_Arguments.back())
           javascript << L", ";
+        if (CFXA_IsTooBig(javascript))
+          return false;
       }
     }
     javascript << L")";
@@ -597,18 +656,22 @@ void CXFA_FMCallExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
       if (!m_Arguments.empty()) {
         const auto& expr = m_Arguments[0];
         javascript << L"return ";
-        expr->ToJavaScript(javascript);
+        if (!expr->ToJavaScript(javascript))
+          return false;
         javascript << L";\n}\n";
       } else {
         javascript << L"return 0;\n}\n";
       }
-      javascript
-          << L"catch(accessExceptions)\n{\nreturn 0;\n}\n}\n).call(this)\n";
+      javascript << L"catch(accessExceptions)\n";
+      javascript << L"{\nreturn 0;\n}\n}\n).call(this)\n";
     } else {
       for (const auto& expr : m_Arguments) {
-        expr->ToJavaScript(javascript);
+        if (!expr->ToJavaScript(javascript))
+          return false;
         if (expr != m_Arguments.back())
           javascript << L", ";
+        if (CFXA_IsTooBig(javascript))
+          return false;
       }
     }
     javascript << L")";
@@ -616,6 +679,7 @@ void CXFA_FMCallExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
       javascript << L")";
     }
   }
+  return true;
 }
 
 CXFA_FMDotAccessorExpression::CXFA_FMDotAccessorExpression(
@@ -632,19 +696,24 @@ CXFA_FMDotAccessorExpression::CXFA_FMDotAccessorExpression(
 
 CXFA_FMDotAccessorExpression::~CXFA_FMDotAccessorExpression() {}
 
-void CXFA_FMDotAccessorExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMDotAccessorExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << gs_lpStrExpFuncName[DOT];
   javascript << L"(";
+  CFX_WideTextBuf tempExp1;
   if (m_pExp1) {
-    m_pExp1->ToJavaScript(javascript);
+    if (!m_pExp1->ToJavaScript(tempExp1))
+      return false;
+    javascript << tempExp1;
   } else {
     javascript << L"null";
   }
   javascript << L", ";
   javascript << L"\"";
-  if (m_pExp1 && m_pExp1->GetOperatorToken() == TOKidentifier) {
-    m_pExp1->ToJavaScript(javascript);
-  }
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
+  if (m_pExp1 && m_pExp1->GetOperatorToken() == TOKidentifier)
+    javascript << tempExp1;
   javascript << L"\", ";
   if (m_op == TOKdotscream) {
     javascript << L"\"#";
@@ -659,8 +728,10 @@ void CXFA_FMDotAccessorExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
     javascript << m_wsIdentifier;
     javascript << L"\", ";
   }
-  m_pExp2->ToJavaScript(javascript);
+  if (!m_pExp2->ToJavaScript(javascript))
+    return false;
   javascript << L")";
+  return !CFXA_IsTooBig(javascript);
 }
 
 CXFA_FMIndexExpression::CXFA_FMIndexExpression(
@@ -672,7 +743,7 @@ CXFA_FMIndexExpression::CXFA_FMIndexExpression(
       m_accessorIndex(accessorIndex),
       m_bIsStarIndex(bIsStarIndex) {}
 
-void CXFA_FMIndexExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMIndexExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   switch (m_accessorIndex) {
     case ACCESSOR_NO_INDEX:
       javascript << L"0";
@@ -692,11 +763,13 @@ void CXFA_FMIndexExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   if (!m_bIsStarIndex) {
     javascript << L", ";
     if (m_pExp) {
-      m_pExp->ToJavaScript(javascript);
+      if (!m_pExp->ToJavaScript(javascript))
+        return false;
     } else {
       javascript << L"0";
     }
   }
+  return true;
 }
 
 CXFA_FMDotDotAccessorExpression::CXFA_FMDotDotAccessorExpression(
@@ -713,22 +786,29 @@ CXFA_FMDotDotAccessorExpression::CXFA_FMDotDotAccessorExpression(
 
 CXFA_FMDotDotAccessorExpression::~CXFA_FMDotDotAccessorExpression() {}
 
-void CXFA_FMDotDotAccessorExpression::ToJavaScript(
+bool CXFA_FMDotDotAccessorExpression::ToJavaScript(
     CFX_WideTextBuf& javascript) {
   javascript << gs_lpStrExpFuncName[DOTDOT];
   javascript << L"(";
-  m_pExp1->ToJavaScript(javascript);
+  CFX_WideTextBuf tempExp1;
+  if (!m_pExp1->ToJavaScript(tempExp1))
+    return false;
+  javascript << tempExp1;
   javascript << L", ";
   javascript << L"\"";
-  if (m_pExp1 && m_pExp1->GetOperatorToken() == TOKidentifier) {
-    m_pExp1->ToJavaScript(javascript);
-  }
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
+  if (m_pExp1->GetOperatorToken() == TOKidentifier)
+    javascript << tempExp1;
   javascript << L"\", ";
   javascript << L"\"";
   javascript << m_wsIdentifier;
   javascript << L"\", ";
-  m_pExp2->ToJavaScript(javascript);
+  if (!m_pExp2->ToJavaScript(javascript))
+    return false;
   javascript << L")";
+  return !CFXA_IsTooBig(javascript);
 }
 
 CXFA_FMMethodCallExpression::CXFA_FMMethodCallExpression(
@@ -740,11 +820,12 @@ CXFA_FMMethodCallExpression::CXFA_FMMethodCallExpression(
                            std::move(pAccessorExp1),
                            std::move(pCallExp)) {}
 
-void CXFA_FMMethodCallExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
+bool CXFA_FMMethodCallExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L"(\nfunction ()\n{\n";
   javascript << L"var method_return_value = null;\n";
   javascript << L"var accessor_object = ";
-  m_pExp1->ToJavaScript(javascript);
+  if (!m_pExp1->ToJavaScript(javascript))
+    return false;
   javascript << L";\n";
   javascript << L"if (";
   javascript << gs_lpStrExpFuncName[ISFMARRAY];
@@ -752,11 +833,22 @@ void CXFA_FMMethodCallExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   javascript << L"for(var index = accessor_object.length - 1; index > 1; "
                 L"index--)\n{\n";
   javascript << L"method_return_value = accessor_object[index].";
-  m_pExp2->ToJavaScript(javascript);
+  if (CFXA_IsTooBig(javascript))
+    return false;
+
+  CFX_WideTextBuf tempExp2;
+  if (!m_pExp2->ToJavaScript(tempExp2))
+    return false;
+  javascript << tempExp2;
   javascript << L";\n}\n}\n";
   javascript << L"else\n{\nmethod_return_value = accessor_object.";
-  m_pExp2->ToJavaScript(javascript);
+  javascript << tempExp2;
   javascript << L";\n}\n";
   javascript << L"return method_return_value;\n";
   javascript << L"}\n).call(this)";
+  return !CFXA_IsTooBig(javascript);
+}
+
+bool CFXA_IsTooBig(const CFX_WideTextBuf& javascript) {
+  return javascript.GetSize() > 256 * 1024 * 1024;
 }
diff --git a/xfa/fxfa/fm2js/xfa_simpleexpression.h b/xfa/fxfa/fm2js/xfa_simpleexpression.h
index af1d02eea5..cb40e2b987 100644
--- a/xfa/fxfa/fm2js/xfa_simpleexpression.h
+++ b/xfa/fxfa/fm2js/xfa_simpleexpression.h
@@ -59,28 +59,28 @@ class CXFA_FMSimpleExpression {
  public:
   CXFA_FMSimpleExpression(uint32_t line, XFA_FM_TOKEN op);
   virtual ~CXFA_FMSimpleExpression() {}
-  virtual void ToJavaScript(CFX_WideTextBuf& javascript);
-  virtual void ToImpliedReturnJS(CFX_WideTextBuf& javascript);
+  virtual bool ToJavaScript(CFX_WideTextBuf& javascript);
+  virtual bool ToImpliedReturnJS(CFX_WideTextBuf& javascript);
 
   XFA_FM_TOKEN GetOperatorToken() const;
 
  protected:
   uint32_t m_line;
-  XFA_FM_TOKEN m_op;
+  const XFA_FM_TOKEN m_op;
 };
 
 class CXFA_FMNullExpression : public CXFA_FMSimpleExpression {
  public:
   explicit CXFA_FMNullExpression(uint32_t line);
   ~CXFA_FMNullExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 };
 
 class CXFA_FMNumberExpression : public CXFA_FMSimpleExpression {
  public:
   CXFA_FMNumberExpression(uint32_t line, CFX_WideStringC wsNumber);
   ~CXFA_FMNumberExpression() override;
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 
  private:
   CFX_WideStringC m_wsNumber;
@@ -90,7 +90,7 @@ class CXFA_FMStringExpression : public CXFA_FMSimpleExpression {
  public:
   CXFA_FMStringExpression(uint32_t line, CFX_WideStringC wsString);
   ~CXFA_FMStringExpression() override;
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 
  private:
   CFX_WideStringC m_wsString;
@@ -100,7 +100,7 @@ class CXFA_FMIdentifierExpression : public CXFA_FMSimpleExpression {
  public:
   CXFA_FMIdentifierExpression(uint32_t line, CFX_WideStringC wsIdentifier);
   ~CXFA_FMIdentifierExpression() override;
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 
  private:
   CFX_WideStringC m_wsIdentifier;
@@ -113,7 +113,7 @@ class CXFA_FMUnaryExpression : public CXFA_FMSimpleExpression {
                          std::unique_ptr<CXFA_FMSimpleExpression> pExp);
   ~CXFA_FMUnaryExpression() override;
 
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 
  protected:
   std::unique_ptr<CXFA_FMSimpleExpression> m_pExp;
@@ -127,7 +127,7 @@ class CXFA_FMBinExpression : public CXFA_FMSimpleExpression {
                        std::unique_ptr<CXFA_FMSimpleExpression> pExp2);
   ~CXFA_FMBinExpression() override;
 
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 
  protected:
   std::unique_ptr<CXFA_FMSimpleExpression> m_pExp1;
@@ -141,8 +141,8 @@ class CXFA_FMAssignExpression : public CXFA_FMBinExpression {
                           std::unique_ptr<CXFA_FMSimpleExpression> pExp1,
                           std::unique_ptr<CXFA_FMSimpleExpression> pExp2);
   ~CXFA_FMAssignExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
-  void ToImpliedReturnJS(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToImpliedReturnJS(CFX_WideTextBuf& javascript) override;
 };
 
 class CXFA_FMLogicalOrExpression : public CXFA_FMBinExpression {
@@ -152,7 +152,7 @@ class CXFA_FMLogicalOrExpression : public CXFA_FMBinExpression {
                              std::unique_ptr<CXFA_FMSimpleExpression> pExp1,
                              std::unique_ptr<CXFA_FMSimpleExpression> pExp2);
   ~CXFA_FMLogicalOrExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 };
 
 class CXFA_FMLogicalAndExpression : public CXFA_FMBinExpression {
@@ -162,7 +162,7 @@ class CXFA_FMLogicalAndExpression : public CXFA_FMBinExpression {
                               std::unique_ptr<CXFA_FMSimpleExpression> pExp1,
                               std::unique_ptr<CXFA_FMSimpleExpression> pExp2);
   ~CXFA_FMLogicalAndExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 };
 
 class CXFA_FMEqualityExpression : public CXFA_FMBinExpression {
@@ -172,7 +172,7 @@ class CXFA_FMEqualityExpression : public CXFA_FMBinExpression {
                             std::unique_ptr<CXFA_FMSimpleExpression> pExp1,
                             std::unique_ptr<CXFA_FMSimpleExpression> pExp2);
   ~CXFA_FMEqualityExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 };
 
 class CXFA_FMRelationalExpression : public CXFA_FMBinExpression {
@@ -182,7 +182,7 @@ class CXFA_FMRelationalExpression : public CXFA_FMBinExpression {
                               std::unique_ptr<CXFA_FMSimpleExpression> pExp1,
                               std::unique_ptr<CXFA_FMSimpleExpression> pExp2);
   ~CXFA_FMRelationalExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 };
 
 class CXFA_FMAdditiveExpression : public CXFA_FMBinExpression {
@@ -192,7 +192,7 @@ class CXFA_FMAdditiveExpression : public CXFA_FMBinExpression {
                             std::unique_ptr<CXFA_FMSimpleExpression> pExp1,
                             std::unique_ptr<CXFA_FMSimpleExpression> pExp2);
   ~CXFA_FMAdditiveExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 };
 
 class CXFA_FMMultiplicativeExpression : public CXFA_FMBinExpression {
@@ -203,7 +203,7 @@ class CXFA_FMMultiplicativeExpression : public CXFA_FMBinExpression {
       std::unique_ptr<CXFA_FMSimpleExpression> pExp1,
       std::unique_ptr<CXFA_FMSimpleExpression> pExp2);
   ~CXFA_FMMultiplicativeExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 };
 
 class CXFA_FMPosExpression : public CXFA_FMUnaryExpression {
@@ -211,7 +211,7 @@ class CXFA_FMPosExpression : public CXFA_FMUnaryExpression {
   CXFA_FMPosExpression(uint32_t line,
                        std::unique_ptr<CXFA_FMSimpleExpression> pExp);
   ~CXFA_FMPosExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 };
 
 class CXFA_FMNegExpression : public CXFA_FMUnaryExpression {
@@ -219,7 +219,7 @@ class CXFA_FMNegExpression : public CXFA_FMUnaryExpression {
   CXFA_FMNegExpression(uint32_t line,
                        std::unique_ptr<CXFA_FMSimpleExpression> pExp);
   ~CXFA_FMNegExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 };
 
 class CXFA_FMNotExpression : public CXFA_FMUnaryExpression {
@@ -227,7 +227,7 @@ class CXFA_FMNotExpression : public CXFA_FMUnaryExpression {
   CXFA_FMNotExpression(uint32_t line,
                        std::unique_ptr<CXFA_FMSimpleExpression> pExp);
   ~CXFA_FMNotExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 };
 
 class CXFA_FMCallExpression : public CXFA_FMUnaryExpression {
@@ -241,7 +241,7 @@ class CXFA_FMCallExpression : public CXFA_FMUnaryExpression {
 
   bool IsBuildInFunc(CFX_WideTextBuf* funcName);
   uint32_t IsMethodWithObjParam(const CFX_WideStringC& methodName);
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 
  private:
   bool m_bIsSomMethod;
@@ -257,7 +257,7 @@ class CXFA_FMDotAccessorExpression : public CXFA_FMBinExpression {
       CFX_WideStringC wsIdentifier,
       std::unique_ptr<CXFA_FMSimpleExpression> pIndexExp);
   ~CXFA_FMDotAccessorExpression() override;
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 
  private:
   CFX_WideStringC m_wsIdentifier;
@@ -270,7 +270,7 @@ class CXFA_FMIndexExpression : public CXFA_FMUnaryExpression {
                          std::unique_ptr<CXFA_FMSimpleExpression> pIndexExp,
                          bool bIsStarIndex);
   ~CXFA_FMIndexExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 
  private:
   XFA_FM_AccessorIndex m_accessorIndex;
@@ -287,7 +287,7 @@ class CXFA_FMDotDotAccessorExpression : public CXFA_FMBinExpression {
       std::unique_ptr<CXFA_FMSimpleExpression> pIndexExp);
   ~CXFA_FMDotDotAccessorExpression() override;
 
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 
  private:
   CFX_WideStringC m_wsIdentifier;
@@ -300,7 +300,9 @@ class CXFA_FMMethodCallExpression : public CXFA_FMBinExpression {
       std::unique_ptr<CXFA_FMSimpleExpression> pAccessorExp1,
       std::unique_ptr<CXFA_FMSimpleExpression> pCallExp);
   ~CXFA_FMMethodCallExpression() override {}
-  void ToJavaScript(CFX_WideTextBuf& javascript) override;
+  bool ToJavaScript(CFX_WideTextBuf& javascript) override;
 };
 
+bool CFXA_IsTooBig(const CFX_WideTextBuf& javascript);
+
 #endif  // XFA_FXFA_FM2JS_XFA_SIMPLEEXPRESSION_H_