Fix some issues with CXFA_FMParse/CXFA_FMLexer infinite looping.

xfa/src/fxfa/src/fm2js/xfa_lexer.h

Index: xfa/src/fxfa/src/fm2js/xfa_lexer.h
diff --git a/xfa/src/fxfa/src/fm2js/xfa_lexer.h b/xfa/src/fxfa/src/fm2js/xfa_lexer.h
index 85b647e46ccf13e06f76e9733f6e1cafaa08486b..14b927d6d93b199eacd1a405091d612d92daa876 100644
--- a/xfa/src/fxfa/src/fm2js/xfa_lexer.h
+++ b/xfa/src/fxfa/src/fm2js/xfa_lexer.h
@@ -6,6 +6,9 @@
 
 #ifndef _XFA_FM_LEXER_H
 #define _XFA_FM_LEXER_H
+
+#include <memory>
+
 enum XFA_FM_TOKEN {
   TOKand,
   TOKlparen,
@@ -76,26 +79,28 @@ enum XFA_FM_TOKEN {
   TOKnumber,
   TOKreserver
 };
+
 struct XFA_FMKeyword {
   XFA_FM_TOKEN m_type;
   uint32_t m_uHash;
   const FX_WCHAR* m_keword;
 };
+
 const FX_WCHAR* XFA_FM_KeywordToString(XFA_FM_TOKEN op);
+
 class CXFA_FMToken {
  public:
   CXFA_FMToken();
-  CXFA_FMToken(FX_DWORD uLineNum);
-  ~CXFA_FMToken();
+  explicit CXFA_FMToken(FX_DWORD uLineNum);
+
   CFX_WideStringC m_wstring;
   XFA_FM_TOKEN m_type;
   FX_DWORD m_uLinenum;
-  CXFA_FMToken* m_pNext;
 };
+
 class CXFA_FMLexer {
  public:
   CXFA_FMLexer(const CFX_WideStringC& wsFormcalc, CXFA_FMErrorInfo* pErrorInfo);
-  ~CXFA_FMLexer();
   CXFA_FMToken* NextToken();
   FX_DWORD Number(CXFA_FMToken* t, const FX_WCHAR* p, const FX_WCHAR*& pEnd);
   FX_DWORD String(CXFA_FMToken* t, const FX_WCHAR* p, const FX_WCHAR*& pEnd);
@@ -106,10 +111,8 @@ class CXFA_FMLexer {
   XFA_FM_TOKEN IsKeyword(const CFX_WideStringC& p);
   void SetCurrentLine(FX_DWORD line) { m_uCurrentLine = line; }
   void SetToken(CXFA_FMToken* pToken) {
-    if (m_pToken) {
-      delete m_pToken;
-    }
-    m_pToken = pToken;
+    if (m_pToken.get() != pToken)
+      m_pToken.reset(pToken);
   }
   const FX_WCHAR* SavePos() { return m_ptr; }
   void RestorePos(const FX_WCHAR* pPos) { m_ptr = pPos; }
@@ -118,11 +121,11 @@ class CXFA_FMLexer {
 
  protected:
   CXFA_FMToken* Scan();
-  const FX_WCHAR* m_pScript;
+
   const FX_WCHAR* m_ptr;
-  FX_STRSIZE m_uLength;
   FX_DWORD m_uCurrentLine;
-  CXFA_FMToken* m_pToken;
+  std::unique_ptr<CXFA_FMToken> m_pToken;
   CXFA_FMErrorInfo* m_pErrorInfo;
 };
+
 #endif