base/win/scoped_variant.cc

// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/win/scoped_variant.h"

#include "base/logging.h"

namespace base {
namespace win {

// Global, const instance of an empty variant.
const VARIANT ScopedVariant::kEmptyVariant = {{{VT_EMPTY}}};

ScopedVariant::~ScopedVariant() {
  static_assert(sizeof(ScopedVariant) == sizeof(VARIANT), "ScopedVariantSize");
  ::VariantClear(&var_);
}

ScopedVariant::ScopedVariant(const wchar_t* str) {
  var_.vt = VT_EMPTY;
  Set(str);
}

ScopedVariant::ScopedVariant(const wchar_t* str, UINT length) {
  var_.vt = VT_BSTR;
  var_.bstrVal = ::SysAllocStringLen(str, length);
}

ScopedVariant::ScopedVariant(int value, VARTYPE vt) {
  var_.vt = vt;
  var_.lVal = value;
}

ScopedVariant::ScopedVariant(double value, VARTYPE vt) {
  DCHECK(vt == VT_R8 || vt == VT_DATE);
  var_.vt = vt;
  var_.dblVal = value;
}

ScopedVariant::ScopedVariant(IDispatch* dispatch) {
  var_.vt = VT_EMPTY;
  Set(dispatch);
}

ScopedVariant::ScopedVariant(IUnknown* unknown) {
  var_.vt = VT_EMPTY;
  Set(unknown);
}

ScopedVariant::ScopedVariant(SAFEARRAY* safearray) {
  var_.vt = VT_EMPTY;
  Set(safearray);
}

ScopedVariant::ScopedVariant(const VARIANT& var) {
  var_.vt = VT_EMPTY;
  Set(var);
}

void ScopedVariant::Reset(const VARIANT& var) {
  if (&var != &var_) {
    ::VariantClear(&var_);
    var_ = var;
  }
}

VARIANT ScopedVariant::Release() {
  VARIANT var = var_;
  var_.vt = VT_EMPTY;
  return var;
}

void ScopedVariant::Swap(ScopedVariant& var) {
  VARIANT tmp = var_;
  var_ = var.var_;
  var.var_ = tmp;
}

VARIANT* ScopedVariant::Receive() {
  DCHECK(!IsLeakableVarType(var_.vt)) << "variant leak. type: " << var_.vt;
  return &var_;
}

VARIANT ScopedVariant::Copy() const {
  VARIANT ret = {{{VT_EMPTY}}};
  ::VariantCopy(&ret, &var_);
  return ret;
}

int ScopedVariant::Compare(const VARIANT& var, bool ignore_case) const {
  ULONG flags = ignore_case ? NORM_IGNORECASE : 0;
  HRESULT hr = ::VarCmp(const_cast<VARIANT*>(&var_), const_cast<VARIANT*>(&var),
                        LOCALE_USER_DEFAULT, flags);
  int ret = 0;

  switch (hr) {
    case VARCMP_LT:
      ret = -1;
      break;

    case VARCMP_GT:
    case VARCMP_NULL:
      ret = 1;
      break;

    default:
      // Equal.
      break;
  }

  return ret;
}

void ScopedVariant::Set(const wchar_t* str) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_BSTR;
  var_.bstrVal = ::SysAllocString(str);
}

void ScopedVariant::Set(int8_t i8) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_I1;
  var_.cVal = i8;
}

void ScopedVariant::Set(uint8_t ui8) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_UI1;
  var_.bVal = ui8;
}

void ScopedVariant::Set(int16_t i16) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_I2;
  var_.iVal = i16;
}

void ScopedVariant::Set(uint16_t ui16) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_UI2;
  var_.uiVal = ui16;
}

void ScopedVariant::Set(int32_t i32) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_I4;
  var_.lVal = i32;
}

void ScopedVariant::Set(uint32_t ui32) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_UI4;
  var_.ulVal = ui32;
}

void ScopedVariant::Set(int64_t i64) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_I8;
  var_.llVal = i64;
}

void ScopedVariant::Set(uint64_t ui64) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_UI8;
  var_.ullVal = ui64;
}

void ScopedVariant::Set(float r32) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_R4;
  var_.fltVal = r32;
}

void ScopedVariant::Set(double r64) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_R8;
  var_.dblVal = r64;
}

void ScopedVariant::SetDate(DATE date) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_DATE;
  var_.date = date;
}

void ScopedVariant::Set(IDispatch* disp) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_DISPATCH;
  var_.pdispVal = disp;
  if (disp)
    disp->AddRef();
}

void ScopedVariant::Set(bool b) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_BOOL;
  var_.boolVal = b ? VARIANT_TRUE : VARIANT_FALSE;
}

void ScopedVariant::Set(IUnknown* unk) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  var_.vt = VT_UNKNOWN;
  var_.punkVal = unk;
  if (unk)
    unk->AddRef();
}

void ScopedVariant::Set(SAFEARRAY* array) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  if (SUCCEEDED(::SafeArrayGetVartype(array, &var_.vt))) {
    var_.vt |= VT_ARRAY;
    var_.parray = array;
  } else {
    DCHECK(!array) << "Unable to determine safearray vartype";
    var_.vt = VT_EMPTY;
  }
}

void ScopedVariant::Set(const VARIANT& var) {
  DCHECK(!IsLeakableVarType(var_.vt)) << "leaking variant: " << var_.vt;
  if (FAILED(::VariantCopy(&var_, &var))) {
    DLOG(ERROR) << "VariantCopy failed";
    var_.vt = VT_EMPTY;
  }
}

ScopedVariant& ScopedVariant::operator=(const VARIANT& var) {
  if (&var != &var_) {
    VariantClear(&var_);
    Set(var);
  }
  return *this;
}

bool ScopedVariant::IsLeakableVarType(VARTYPE vt) {
  bool leakable = false;
  switch (vt & VT_TYPEMASK) {
    case VT_BSTR:
    case VT_DISPATCH:
    // we treat VT_VARIANT as leakable to err on the safe side.
    case VT_VARIANT:
    case VT_UNKNOWN:
    case VT_SAFEARRAY:

    // very rarely used stuff (if ever):
    case VT_VOID:
    case VT_PTR:
    case VT_CARRAY:
    case VT_USERDEFINED:
    case VT_LPSTR:
    case VT_LPWSTR:
    case VT_RECORD:
    case VT_INT_PTR:
    case VT_UINT_PTR:
    case VT_FILETIME:
    case VT_BLOB:
    case VT_STREAM:
    case VT_STORAGE:
    case VT_STREAMED_OBJECT:
    case VT_STORED_OBJECT:
    case VT_BLOB_OBJECT:
    case VT_VERSIONED_STREAM:
    case VT_BSTR_BLOB:
      leakable = true;
      break;
  }

  if (!leakable && (vt & VT_ARRAY) != 0) {
    leakable = true;
  }

  return leakable;
}

}  // namespace win
}  // namespace base