DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (c7bae7b13ad4)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_FileUtilsWin_h
#define mozilla_FileUtilsWin_h

#include <windows.h>

#include "mozilla/Scoped.h"
#include "nsString.h"

namespace mozilla {

inline bool EnsureLongPath(nsAString& aDosPath) {
  nsAutoString inputPath(aDosPath);
  while (true) {
    DWORD requiredLength = GetLongPathNameW(
        inputPath.get(), reinterpret_cast<wchar_t*>(aDosPath.BeginWriting()),
        aDosPath.Length());
    if (!requiredLength) {
      return false;
    }
    if (requiredLength < aDosPath.Length()) {
      // When GetLongPathNameW deems the last argument too small,
      // it returns a value, but when you pass that value back, it's
      // satisfied and returns a number that's one smaller. If the above
      // check was == instead of <, the loop would go on forever with
      // GetLongPathNameW returning oscillating values!
      aDosPath.Truncate(requiredLength);
      return true;
    }
    aDosPath.SetLength(requiredLength);
  }
}

inline bool NtPathToDosPath(const nsAString& aNtPath, nsAString& aDosPath) {
  aDosPath.Truncate();
  if (aNtPath.IsEmpty()) {
    return true;
  }
  NS_NAMED_LITERAL_STRING(symLinkPrefix, "\\??\\");
  uint32_t ntPathLen = aNtPath.Length();
  uint32_t symLinkPrefixLen = symLinkPrefix.Length();
  if (ntPathLen >= 6 && aNtPath.CharAt(5) == L':' &&
      ntPathLen >= symLinkPrefixLen &&
      Substring(aNtPath, 0, symLinkPrefixLen).Equals(symLinkPrefix)) {
    // Symbolic link for DOS device. Just strip off the prefix.
    aDosPath = aNtPath;
    aDosPath.Cut(0, 4);
    return true;
  }
  nsAutoString logicalDrives;
  while (true) {
    DWORD requiredLength = GetLogicalDriveStringsW(
        logicalDrives.Length(),
        reinterpret_cast<wchar_t*>(logicalDrives.BeginWriting()));
    if (!requiredLength) {
      return false;
    }
    if (requiredLength < logicalDrives.Length()) {
      // When GetLogicalDriveStringsW deems the first argument too small,
      // it returns a value, but when you pass that value back, it's
      // satisfied and returns a number that's one smaller. If the above
      // check was == instead of <, the loop would go on forever with
      // GetLogicalDriveStringsW returning oscillating values!
      logicalDrives.Truncate(requiredLength);
      // logicalDrives now has the format "C:\\\0D:\\\0Z:\\\0". That is,
      // the sequence drive letter, colon, backslash, U+0000 repeats.
      break;
    }
    logicalDrives.SetLength(requiredLength);
  }

  const char16_t* cur = logicalDrives.BeginReading();
  const char16_t* end = logicalDrives.EndReading();
  nsString targetPath;
  targetPath.SetLength(MAX_PATH);
  wchar_t driveTemplate[] = L" :";
  while (cur < end) {
    // Unfortunately QueryDosDevice doesn't support the idiom for querying the
    // output buffer size, so it may require retries.
    driveTemplate[0] = *cur;
    DWORD targetPathLen = 0;
    SetLastError(ERROR_SUCCESS);
    while (true) {
      targetPathLen = QueryDosDeviceW(
          driveTemplate, reinterpret_cast<wchar_t*>(targetPath.BeginWriting()),
          targetPath.Length());
      if (targetPathLen || GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
        break;
      }
      targetPath.SetLength(targetPath.Length() * 2);
    }
    if (targetPathLen) {
      // Need to use wcslen here because targetPath contains embedded NULL chars
      size_t firstTargetPathLen = wcslen(targetPath.get());
      const char16_t* pathComponent =
          aNtPath.BeginReading() + firstTargetPathLen;
      bool found = _wcsnicmp(char16ptr_t(aNtPath.BeginReading()),
                             targetPath.get(), firstTargetPathLen) == 0 &&
                   *pathComponent == L'\\';
      if (found) {
        aDosPath = driveTemplate;
        aDosPath += pathComponent;
        return EnsureLongPath(aDosPath);
      }
    }
    // Find the next U+0000 within the logical string
    while (*cur) {
      // This loop skips the drive letter, the colon
      // and the backslash.
      cur++;
    }
    // Skip over the U+0000 that ends a drive entry
    // within the logical string
    cur++;
  }
  // Try to handle UNC paths. NB: This must happen after we've checked drive
  // mappings in case a UNC path is mapped to a drive!
  NS_NAMED_LITERAL_STRING(uncPrefix, "\\\\");
  NS_NAMED_LITERAL_STRING(deviceMupPrefix, "\\Device\\Mup\\");
  if (StringBeginsWith(aNtPath, deviceMupPrefix)) {
    aDosPath = uncPrefix;
    aDosPath += Substring(aNtPath, deviceMupPrefix.Length());
    return true;
  }
  NS_NAMED_LITERAL_STRING(deviceLanmanRedirectorPrefix,
                          "\\Device\\LanmanRedirector\\");
  if (StringBeginsWith(aNtPath, deviceLanmanRedirectorPrefix)) {
    aDosPath = uncPrefix;
    aDosPath += Substring(aNtPath, deviceLanmanRedirectorPrefix.Length());
    return true;
  }
  return false;
}

bool HandleToFilename(HANDLE aHandle, const LARGE_INTEGER& aOffset,
                      nsAString& aFilename);

}  // namespace mozilla

#endif  // mozilla_FileUtilsWin_h