xpcom/io/FileUtilsWin.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_FileUtilsWin_h
   8 #define mozilla_FileUtilsWin_h
   9
  10 #include <windows.h>
  11
  12 #include "mozilla/Scoped.h"
  13 #include "nsStringGlue.h"
  14
  15 namespace mozilla {
  16
  17 inline bool
  18 NtPathToDosPath(const nsAString& aNtPath, nsAString& aDosPath)
  19 {
  20   aDosPath.Truncate();
  21   if (aNtPath.IsEmpty()) {
  22     return true;
  23   }
  24   NS_NAMED_LITERAL_STRING(symLinkPrefix, "\\??\\");
  25   uint32_t ntPathLen = aNtPath.Length();
  26   uint32_t symLinkPrefixLen = symLinkPrefix.Length();
  27   if (ntPathLen >= 6 && aNtPath.CharAt(5) == L':' &&
  28       ntPathLen >= symLinkPrefixLen &&
  29       Substring(aNtPath, 0, symLinkPrefixLen).Equals(symLinkPrefix)) {
  30     // Symbolic link for DOS device. Just strip off the prefix.
  31     aDosPath = aNtPath;
  32     aDosPath.Cut(0, 4);
  33     return true;
  34   }
  35   nsAutoString logicalDrives;
  36   DWORD len = 0;
  37   while (true) {
  38     len = GetLogicalDriveStringsW(
  39       len, reinterpret_cast<wchar_t*>(logicalDrives.BeginWriting()));
  40     if (!len) {
  41       return false;
  42     } else if (len > logicalDrives.Length()) {
  43       logicalDrives.SetLength(len);
  44     } else {
  45       break;
  46     }
  47   }
  48   const char16_t* cur = logicalDrives.BeginReading();
  49   const char16_t* end = logicalDrives.EndReading();
  50   nsString targetPath;
  51   targetPath.SetLength(MAX_PATH);
  52   wchar_t driveTemplate[] = L" :";
  53   do {
  54     // Unfortunately QueryDosDevice doesn't support the idiom for querying the
  55     // output buffer size, so it may require retries.
  56     driveTemplate[0] = *cur;
  57     DWORD targetPathLen = 0;
  58     SetLastError(ERROR_SUCCESS);
  59     while (true) {
  60       targetPathLen = QueryDosDeviceW(driveTemplate,
  61                                       reinterpret_cast<wchar_t*>(targetPath.BeginWriting()),
  62                                       targetPath.Length());
  63       if (targetPathLen || GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
  64         break;
  65       }
  66       targetPath.SetLength(targetPath.Length() * 2);
  67     }
  68     if (targetPathLen) {
  69       // Need to use wcslen here because targetPath contains embedded NULL chars
  70       size_t firstTargetPathLen = wcslen(targetPath.get());
  71       const char16_t* pathComponent = aNtPath.BeginReading() +
  72                                       firstTargetPathLen;
  73       bool found = _wcsnicmp(char16ptr_t(aNtPath.BeginReading()), targetPath.get(),
  74                              firstTargetPathLen) == 0 &&
  75                    *pathComponent == L'\\';
  76       if (found) {
  77         aDosPath = driveTemplate;
  78         aDosPath += pathComponent;
  79         return true;
  80       }
  81     }
  82     // Advance to the next NUL character in logicalDrives
  83     while (*cur++);
  84   } while (cur != end);
  85   // Try to handle UNC paths. NB: This must happen after we've checked drive
  86   // mappings in case a UNC path is mapped to a drive!
  87   NS_NAMED_LITERAL_STRING(uncPrefix, "\\\\");
  88   NS_NAMED_LITERAL_STRING(deviceMupPrefix, "\\Device\\Mup\\");
  89   if (StringBeginsWith(aNtPath, deviceMupPrefix)) {
  90     aDosPath = uncPrefix;
  91     aDosPath += Substring(aNtPath, deviceMupPrefix.Length());
  92     return true;
  93   }
  94   NS_NAMED_LITERAL_STRING(deviceLanmanRedirectorPrefix,
  95                           "\\Device\\LanmanRedirector\\");
  96   if (StringBeginsWith(aNtPath, deviceLanmanRedirectorPrefix)) {
  97     aDosPath = uncPrefix;
  98     aDosPath += Substring(aNtPath, deviceLanmanRedirectorPrefix.Length());
  99     return true;
 100   }
 101   return false;
 102 }
 103
 104 bool
 105 HandleToFilename(HANDLE aHandle, const LARGE_INTEGER& aOffset,
 106                  nsAString& aFilename);
 107
 108 } // namespace mozilla
 109
 110 #endif // mozilla_FileUtilsWin_h