Move BSTR wrapper to systools, and fix some wrong BSTR uses

BSTR is documented [1] to be prefixed by a 32-bit integer specifying
its length *in bytes* (not characters), so passing wchar_t* as BSTR
is wrong, and the length member of rtl_uString can't substitute the
proper BSTR length, since rtl_uString::length specifies length in
characters. Any code taking BSTR and using SysStringLen to get its
length would only get half of the passed OUString data.

In dbaccess/source/ui/dlg/adodatalinks.cxx, the abovementioned
error was implemented. OTOH, OLEVariant::getByteSequence() in
connectivity/source/drivers/ado/Aolevariant.cxx passed BSTR from
tagVARIANT to ctor of OLEString, which resulted in the BSTR being
freed in both dtors of OLEString and OLEVariant (the latter calls
VariantClear, which itself clears string when vtfield is VT_BSTR).

[1] https://docs.microsoft.com/en-us/previous-versions/windows/desktop/automat/bstr

Change-Id: Iedbd62b20133644258af3660616add7b63cac258
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/131950
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

3 files changed, 15 insertions, 26 deletions

diff --git a/extensions/source/activex/SOActiveX.cxx b/extensions/source/activex/SOActiveX.cxx
index 2d8dc2a73b91..88b3ad7691ca 100644
--- a/extensions/source/activex/SOActiveX.cxx
+++ b/extensions/source/activex/SOActiveX.cxx
@@ -359,7 +359,7 @@ COM_DECLSPEC_NOTHROW STDMETHODIMP CSOActiveX::Load( LPPROPERTYBAG pPropBag, LPER
         // all information from the 'object' tag is in strings
         if (aVal[ind].vt == VT_BSTR && !wcscmp(aPropNames[ind].pstrName, L"src"))
         {
-            mCurFileUrl = wcsdup( aVal[ind].bstrVal );
+            mCurFileUrl.AssignBSTR(aVal[ind].bstrVal);
         }
         else if( aVal[ind].vt == VT_BSTR
                 && !wcscmp(aPropNames[ind].pstrName, L"readonly"))
@@ -384,16 +384,10 @@ COM_DECLSPEC_NOTHROW STDMETHODIMP CSOActiveX::Load( LPPROPERTYBAG pPropBag, LPER
         return hr;
 
     mbReadyForActivation = FALSE;
-    if (BSTR bStrUrl = SysAllocString(mCurFileUrl))
-    {
-        hr = CBindStatusCallback<CSOActiveX>::Download(
-            this, &CSOActiveX::CallbackCreateXInputStream, bStrUrl, m_spClientSite, FALSE);
-        SysFreeString(bStrUrl);
-        if (hr == MK_S_ASYNCHRONOUS)
-            hr = S_OK;
-    }
-    else
-        hr = E_OUTOFMEMORY;
+    hr = CBindStatusCallback<CSOActiveX>::Download(
+        this, &CSOActiveX::CallbackCreateXInputStream, mCurFileUrl, m_spClientSite, FALSE);
+    if (hr == MK_S_ASYNCHRONOUS)
+        hr = S_OK;
 
     if ( !SUCCEEDED( hr ) )
     {
diff --git a/extensions/source/activex/SOActiveX.h b/extensions/source/activex/SOActiveX.h
index f3a66e183ed5..37d983ae91d5 100644
--- a/extensions/source/activex/SOActiveX.h
+++ b/extensions/source/activex/SOActiveX.h
@@ -81,7 +81,7 @@ protected:
     CComPtr<IDispatch>      mpDispFrame;
     CComPtr<IDispatch>      mpInstanceLocker;
     CComPtr<IDispatch>      mpDispWin;
-    OLECHAR const *         mCurFileUrl;
+    CComBSTR                mCurFileUrl;
     BOOL                    mbLoad;
     BOOL                    mbViewOnly;
     WNDCLASSW               mPWinClass;
diff --git a/extensions/source/config/WinUserInfo/WinUserInfoBe.cxx b/extensions/source/config/WinUserInfo/WinUserInfoBe.cxx
index 9b721d50b36a..787769b50367 100644
--- a/extensions/source/config/WinUserInfo/WinUserInfoBe.cxx
+++ b/extensions/source/config/WinUserInfo/WinUserInfoBe.cxx
@@ -25,6 +25,7 @@
 #include <Security.h>
 
 #include <systools/win32/comtools.hxx>
+#include <systools/win32/oleauto.hxx>
 
 namespace extensions
 {
@@ -93,12 +94,12 @@ public:
             sal::systools::COMReference<IADsADSystemInfo> pADsys(CLSID_ADSystemInfo, nullptr,
                                                                  CLSCTX_INPROC_SERVER);
 
-            smartBSTR sUserDN;
-            sal::systools::ThrowIfFailed(pADsys->get_UserName(&sUserDN.ptr), "get_UserName failed");
+            sal::systools::BStr sUserDN;
+            sal::systools::ThrowIfFailed(pADsys->get_UserName(&sUserDN), "get_UserName failed");
             // If this user is an AD user, then without an active connection to the domain, all the
             // above will succeed, and m_sUserDN will be correctly initialized, but the following
             // call to ADsGetObject will fail, and we will attempt reading cached values.
-            m_sUserDN = o3tl::toU(sUserDN.ptr);
+            m_sUserDN = sUserDN;
             OUString sLdapUserDN = "LDAP://" + m_sUserDN;
             sal::systools::COMReference<IADsUser> pUser;
             sal::systools::ThrowIfFailed(ADsGetObject(o3tl::toW(sLdapUserDN.getStr()), IID_IADsUser,
@@ -146,29 +147,23 @@ public:
     virtual OUString GetMail() override { return m_aMap[mail]; }
 
 private:
-    struct smartBSTR
-    {
-        BSTR ptr = nullptr;
-        ~smartBSTR() { SysFreeString(ptr); }
-    };
-
     typedef HRESULT (__stdcall IADsUser::*getstrfunc)(BSTR*);
     static OUString Str(IADsUser* pUser, getstrfunc func)
     {
-        smartBSTR sBstr;
-        if (FAILED((pUser->*func)(&sBstr.ptr)))
+        sal::systools::BStr sBstr;
+        if (FAILED((pUser->*func)(&sBstr)))
             return "";
-        return OUString(o3tl::toU(sBstr.ptr));
+        return OUString(sBstr);
     }
     static OUString Str(IADsUser* pUser, const wchar_t* property)
     {
-        smartBSTR sBstrProp{ SysAllocString(property) };
+        sal::systools::BStr sBstrProp{ o3tl::toU(property) };
         struct AutoVariant : public VARIANT
         {
             AutoVariant() { VariantInit(this); }
             ~AutoVariant() { VariantClear(this); }
         } varArr;
-        if (FAILED(pUser->GetEx(sBstrProp.ptr, &varArr)))
+        if (FAILED(pUser->GetEx(sBstrProp, &varArr)))
             return "";
         SAFEARRAY* sa = V_ARRAY(&varArr);
         LONG nStart, nEnd;