base/win/scoped_bstr.cc

   1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/win/scoped_bstr.h"
   6
   7 #include "base/logging.h"
   8
   9 namespace base {
  10 namespace win {
  11
  12 ScopedBstr::ScopedBstr(const char16* non_bstr)
  13     : bstr_(SysAllocString(non_bstr)) {
  14 }
  15
  16 ScopedBstr::~ScopedBstr() {
  17   COMPILE_ASSERT(sizeof(ScopedBstr) == sizeof(BSTR), ScopedBstrSize);
  18   SysFreeString(bstr_);
  19 }
  20
  21 void ScopedBstr::Reset(BSTR bstr) {
  22   if (bstr != bstr_) {
  23     // if |bstr_| is NULL, SysFreeString does nothing.
  24     SysFreeString(bstr_);
  25     bstr_ = bstr;
  26   }
  27 }
  28
  29 BSTR ScopedBstr::Release() {
  30   BSTR bstr = bstr_;
  31   bstr_ = NULL;
  32   return bstr;
  33 }
  34
  35 void ScopedBstr::Swap(ScopedBstr& bstr2) {
  36   BSTR tmp = bstr_;
  37   bstr_ = bstr2.bstr_;
  38   bstr2.bstr_ = tmp;
  39 }
  40
  41 BSTR* ScopedBstr::Receive() {
  42   DCHECK(!bstr_) << "BSTR leak.";
  43   return &bstr_;
  44 }
  45
  46 BSTR ScopedBstr::Allocate(const char16* str) {
  47   Reset(SysAllocString(str));
  48   return bstr_;
  49 }
  50
  51 BSTR ScopedBstr::AllocateBytes(size_t bytes) {
  52   Reset(SysAllocStringByteLen(NULL, static_cast<UINT>(bytes)));
  53   return bstr_;
  54 }
  55
  56 void ScopedBstr::SetByteLen(size_t bytes) {
  57   DCHECK(bstr_ != NULL) << "attempting to modify a NULL bstr";
  58   uint32* data = reinterpret_cast<uint32*>(bstr_);
  59   data[-1] = static_cast<uint32>(bytes);
  60 }
  61
  62 size_t ScopedBstr::Length() const {
  63   return SysStringLen(bstr_);
  64 }
  65
  66 size_t ScopedBstr::ByteLength() const {
  67   return SysStringByteLen(bstr_);
  68 }
  69
  70 }  // namespace win
  71 }  // namespace base