Convert CFXJSE_Value::ToString to return.

xfa/fxjse/value.h

 // Copyright 2014 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
 
 #ifndef XFA_FXJSE_VALUE_H_
 #define XFA_FXJSE_VALUE_H_
 
 #include "xfa/fxjse/scope_inline.h"
@@ skipping 154 matching lines @@
         v8::Local<v8::Value>::New(m_pIsolate, m_hValue);
     return static_cast<double>(hValue->NumberValue());
   }
   V8_INLINE int32_t ToInteger() const {
     ASSERT(!m_hValue.IsEmpty());
     CFXJSE_ScopeUtil_IsolateHandleRootContext scope(m_pIsolate);
     v8::Local<v8::Value> hValue =
         v8::Local<v8::Value>::New(m_pIsolate, m_hValue);
     return static_cast<int32_t>(hValue->NumberValue());
   }
-  V8_INLINE void ToString(CFX_ByteString& szStrOutput) const {
+  V8_INLINE CFX_ByteString ToString() const {
     ASSERT(!m_hValue.IsEmpty());
     CFXJSE_ScopeUtil_IsolateHandleRootContext scope(m_pIsolate);
     v8::Local<v8::Value> hValue =
         v8::Local<v8::Value>::New(m_pIsolate, m_hValue);
     v8::Local<v8::String> hString = hValue->ToString();
     v8::String::Utf8Value hStringVal(hString);
-    szStrOutput = *hStringVal;
+    return CFX_ByteString(*hStringVal);
+  }
+  V8_INLINE CFX_ByteStringC ToStringC() const { return ToString().AsStringC(); }

[Tom Sepez, 2016/06/09 16:43:56]

Nope. The call to ToString() creates a temporary bytestring that lives up until
the semicolon at the end of this statement.  AsStringC doesn't do any copying,
returning pointers into the temporary's buffers.  So we're returing pointers
into something on the stack that gets destructed and popped.

We'll have to put the calls to ToString().AsStringC() into the callers so that
the temporary result of ToString() lives for the duration of what the caller
intends to do with it.

[dsinclair, 2016/06/09 17:26:54]

Done.

+  V8_INLINE CFX_WideString ToWideString() const {
+    return CFX_WideString::FromUTF8(ToStringC());

[Tom Sepez, 2016/06/09 16:47:55]

Note that ToWideString() will be fine (once we fix its ToStringC usage) because
CFX_WideString() allocs and copies.

   }
   CFXJSE_HostObject* ToHostObject(CFXJSE_Class* lpClass) const;
 
   V8_INLINE void SetUndefined() {
     CFXJSE_ScopeUtil_IsolateHandle scope(m_pIsolate);
     v8::Local<v8::Value> hValue = v8::Undefined(m_pIsolate);
     m_hValue.Reset(m_pIsolate, hValue);
   }
   V8_INLINE void SetNull() {
     CFXJSE_ScopeUtil_IsolateHandle scope(m_pIsolate);
@@ skipping 79 matching lines @@
 
   CFXJSE_Value();
   CFXJSE_Value(const CFXJSE_Value&);
   CFXJSE_Value& operator=(const CFXJSE_Value&);
 
   v8::Isolate* m_pIsolate;
   v8::Global<v8::Value> m_hValue;
 };
 
 #endif  // XFA_FXJSE_VALUE_H_