Use safe arithmentic in CFX_BinaryBuf::ExpandBuf.

Always call ExpandBuf(), and if it returns, we know the
subsequent calculations won't overflow.

Also use std::unique_ptr, and fix unintentional copies thus
detected by its suppressed copy ctor in fsdk_baseform.cpp

Also Remove unused CFX_BinaryBuf::TakeOver(), AppendFill(), CopyData().

Also remove operator= in favor of using <<, for similarity
with std::ostream and friends.

Also move ByteStringC methods to CFX_ByteTextBuf sub-class.

Also re-order members, may pack tighter on 64-bits.

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1710403002 .

2 files changed, 19 insertions, 10 deletions

diff --git a/xfa/src/fxfa/src/fm2js/xfa_fm2jscontext.cpp b/xfa/src/fxfa/src/fm2js/xfa_fm2jscontext.cpp
index 529474f5eb..77cf79bd7b 100644
--- a/xfa/src/fxfa/src/fm2js/xfa_fm2jscontext.cpp
+++ b/xfa/src/fxfa/src/fm2js/xfa_fm2jscontext.cpp
@@ -3760,8 +3760,9 @@ void CXFA_FM2JSContext::DecodeURL(const CFX_ByteStringC& szURLString,
     ++i;
   }
   wsResultBuf.AppendChar(0);
-  szResultString =
-      FX_UTF8Encode(wsResultBuf.GetBuffer(), wsResultBuf.GetLength());
+  szResultString.Clear();
+  szResultString << FX_UTF8Encode(wsResultBuf.GetBuffer(),
+                                  wsResultBuf.GetLength());
 }
 void CXFA_FM2JSContext::DecodeHTML(const CFX_ByteStringC& szHTMLString,
                                    CFX_ByteTextBuf& szResultString) {
@@ -3833,8 +3834,9 @@ void CXFA_FM2JSContext::DecodeHTML(const CFX_ByteStringC& szHTMLString,
     ++i;
   }
   wsResultBuf.AppendChar(0);
-  szResultString =
-      FX_UTF8Encode(wsResultBuf.GetBuffer(), wsResultBuf.GetLength());
+  szResultString.Clear();
+  szResultString << FX_UTF8Encode(wsResultBuf.GetBuffer(),
+                                  wsResultBuf.GetLength());
 }
 void CXFA_FM2JSContext::DecodeXML(const CFX_ByteStringC& szXMLString,
                                   CFX_ByteTextBuf& szResultString) {
@@ -3930,7 +3932,8 @@ void CXFA_FM2JSContext::DecodeXML(const CFX_ByteStringC& szXMLString,
     iCode = 0;
   }
   wsXMLBuf.AppendChar(0);
-  szResultString = FX_UTF8Encode(wsXMLBuf.GetBuffer(), wsXMLBuf.GetLength());
+  szResultString.Clear();
+  szResultString << FX_UTF8Encode(wsXMLBuf.GetBuffer(), wsXMLBuf.GetLength());
 }
 void CXFA_FM2JSContext::Encode(FXJSE_HOBJECT hThis,
                                const CFX_ByteStringC& szFuncName,
@@ -4083,7 +4086,9 @@ void CXFA_FM2JSContext::EncodeURL(const CFX_ByteStringC& szURLString,
     }
   }
   wsResultBuf.AppendChar(0);
-  szResultBuf = FX_UTF8Encode(wsResultBuf.GetBuffer(), wsResultBuf.GetLength());
+  szResultBuf.Clear();
+  szResultBuf << FX_UTF8Encode(wsResultBuf.GetBuffer(),
+                               wsResultBuf.GetLength());
 }
 void CXFA_FM2JSContext::EncodeHTML(const CFX_ByteStringC& szHTMLString,
                                    CFX_ByteTextBuf& szResultBuf) {
@@ -4135,7 +4140,9 @@ void CXFA_FM2JSContext::EncodeHTML(const CFX_ByteStringC& szHTMLString,
     ++i;
   }
   wsResultBuf.AppendChar(0);
-  szResultBuf = FX_UTF8Encode(wsResultBuf.GetBuffer(), wsResultBuf.GetLength());
+  szResultBuf.Clear();
+  szResultBuf << FX_UTF8Encode(wsResultBuf.GetBuffer(),
+                               wsResultBuf.GetLength());
 }
 void CXFA_FM2JSContext::EncodeXML(const CFX_ByteStringC& szXMLString,
                                   CFX_ByteTextBuf& szResultBuf) {
@@ -4215,7 +4222,9 @@ void CXFA_FM2JSContext::EncodeXML(const CFX_ByteStringC& szXMLString,
     }
   }
   wsResultBuf.AppendChar(0);
-  szResultBuf = FX_UTF8Encode(wsResultBuf.GetBuffer(), wsResultBuf.GetLength());
+  szResultBuf.Clear();
+  szResultBuf << FX_UTF8Encode(wsResultBuf.GetBuffer(),
+                               wsResultBuf.GetLength());
 }
 FX_BOOL CXFA_FM2JSContext::HTMLSTR2Code(const CFX_WideStringC& pData,
                                         uint32_t& iCode) {
diff --git a/xfa/src/fxfa/src/fm2js/xfa_simpleexpression.cpp b/xfa/src/fxfa/src/fm2js/xfa_simpleexpression.cpp
index c67681f6ba..7048c38d5a 100644
--- a/xfa/src/fxfa/src/fm2js/xfa_simpleexpression.cpp
+++ b/xfa/src/fxfa/src/fm2js/xfa_simpleexpression.cpp
@@ -447,8 +447,8 @@ CXFA_FMCallExpression::~CXFA_FMCallExpression() {
   }
 }
 FX_BOOL CXFA_FMCallExpression::IsBuildInFunc(CFX_WideTextBuf& funcName) {
-  int32_t iLength = funcName.GetLength();
-  uint32_t uHash = FX_HashCode_String_GetW(funcName.GetBuffer(), iLength, TRUE);
+  uint32_t uHash =
+      FX_HashCode_String_GetW(funcName.GetBuffer(), funcName.GetLength(), TRUE);
   XFA_FMBuildInFunc buildinfunction;
   int32_t iStart = 0,
           iEnd = (sizeof(buildInFuncs) / sizeof(buildInFuncs[0])) - 1;