From 60563ce0cef1470431507d0d0f6c31b95611fd93 Mon Sep 17 00:00:00 2001
From: PB <pbfordev@gmail.com>
Date: Fri, 23 Jun 2017 17:06:56 +0200
Subject: [PATCH] Modify wxBasicString so it is better suited to work as an
 RAII wrapper for BSTR.

---
 include/wx/msw/ole/oleutils.h | 45 ++++++++++++++++++++++++------
 src/msw/ole/oleutils.cpp      | 52 +++++++++++++++++++++++++++++------
 2 files changed, 80 insertions(+), 17 deletions(-)

diff --git a/include/wx/msw/ole/oleutils.h b/include/wx/msw/ole/oleutils.h
index 1dab81b18a..2477c25b95 100644
--- a/include/wx/msw/ole/oleutils.h
+++ b/include/wx/msw/ole/oleutils.h
@@ -66,18 +66,45 @@ inline void wxOleUninitialize()
 class WXDLLIMPEXP_CORE wxBasicString
 {
 public:
-    // ctors & dtor
-    wxBasicString(const wxString& str);
-    wxBasicString(const wxBasicString& bstr);
-    ~wxBasicString();
 
-    wxBasicString& operator=(const wxBasicString& bstr);
+	// Takes over the ownership of bstr
+    wxBasicString(BSTR bstr = NULL);
+	
+	// Constructs the BSTR from wxString
+	wxBasicString(const wxString& str);
+    
+	// Creates a copy of the BSTR owned by bstr
+	wxBasicString(const wxBasicString& bstr);
+    
+	// Frees the owned BSTR
+	~wxBasicString();
+	
 
-    // accessors
-        // just get the string
+	// Sets its BSTR to a copy of the BSTR owned by bstr
+	wxBasicString& operator=(const wxBasicString& bstr);
+
+	// Creates its BSTR from wxString
+	wxBasicString& operator=(const wxString& str);
+
+	// Takes over the ownership of bstr
+	wxBasicString& operator=(BSTR bstr);
+
+	// Returns the owned BSTR and gives up its ownership
+	BSTR Detach();
+
+    /// Returns the owned BSTR while keeping its ownership    
     operator BSTR() const { return m_bstrBuf; }
-        // retrieve a copy of our string - caller must SysFreeString() it later!
-    BSTR Get() const { return SysAllocString(m_bstrBuf); }
+     
+	// Returns the address of the owned BSTR
+	operator BSTR*() { return &m_bstrBuf; }
+
+	// Returns a copy of the owned BSTR
+	BSTR Copy() const { return SysAllocString(m_bstrBuf); }
+	
+	
+	// retrieve a copy of our string - caller must SysFreeString() it later!
+	wxDEPRECATED_MSG("use Copy() instead") 
+	BSTR Get() const { return Copy(); }
 
 private:
     // actual string
diff --git a/src/msw/ole/oleutils.cpp b/src/msw/ole/oleutils.cpp
index 67c1477753..b56a1bbf07 100644
--- a/src/msw/ole/oleutils.cpp
+++ b/src/msw/ole/oleutils.cpp
@@ -71,20 +71,19 @@ WXDLLEXPORT wxString wxConvertStringFromOle(BSTR bStr)
 // wxBasicString
 // ----------------------------------------------------------------------------
 
+wxBasicString::wxBasicString(BSTR bstr)
+{
+	m_bstrBuf = bstr;
+}
+
 wxBasicString::wxBasicString(const wxString& str)
 {
     m_bstrBuf = SysAllocString(str.wc_str(*wxConvCurrent));
 }
 
-wxBasicString::wxBasicString(const wxBasicString& src)
+wxBasicString::wxBasicString(const wxBasicString& bstr)
 {
-    m_bstrBuf = src.Get();
-}
-
-wxBasicString& wxBasicString::operator=(const wxBasicString& src)
-{
-    SysReAllocString(&m_bstrBuf, src);
-    return *this;
+    m_bstrBuf = bstr.Copy();
 }
 
 wxBasicString::~wxBasicString()
@@ -92,6 +91,43 @@ wxBasicString::~wxBasicString()
     SysFreeString(m_bstrBuf);
 }
 
+wxBasicString& wxBasicString::operator=(const wxBasicString& src)
+{
+	if ( this != &src )
+	{
+		SysFreeString(m_bstrBuf);
+		m_bstrBuf = src.Copy();
+	}
+
+	return *this;
+}
+
+wxBasicString& wxBasicString::operator=(const wxString& str)
+{
+	SysFreeString(m_bstrBuf);
+	m_bstrBuf = ::SysAllocString(str.wc_str(*wxConvCurrent));
+
+	return *this;
+}
+
+wxBasicString& wxBasicString::operator=(BSTR bstr)
+{
+	wxCHECK_MSG(m_bstrBuf != bstr, *this, wxS("Attempting to attach already attached BSTR!"));
+
+	SysFreeString(m_bstrBuf);
+	m_bstrBuf = bstr;
+
+	return *this;
+}
+
+BSTR wxBasicString::Detach()
+{
+	BSTR bstr = m_bstrBuf;
+
+	m_bstrBuf = NULL;
+	
+	return bstr;
+}
 
 // ----------------------------------------------------------------------------
 // Convert variants