tenfourfox/xpcom/io/FileUtilsWin.h

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2017-04-19 07:56:45 +00:00
/* -*- 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 "nsStringGlue.h"
namespace mozilla {
inline bool
EnsureLongPath(nsAString& aDosPath)
{
uint32_t aDosPathOriginalLen = aDosPath.Length();
auto inputPath = PromiseFlatString(aDosPath);
// Try to get the long path, or else get the required length of the long path
DWORD longPathLen = GetLongPathNameW(inputPath.get(),
reinterpret_cast<wchar_t*>(aDosPath.BeginWriting()),
aDosPathOriginalLen);
if (longPathLen == 0) {
return false;
}
aDosPath.SetLength(longPathLen);
if (longPathLen <= aDosPathOriginalLen) {
// Our string happened to be long enough for the first call to succeed.
return true;
}
// Now we have a large enough buffer, get the actual string
longPathLen = GetLongPathNameW(inputPath.get(),
reinterpret_cast<wchar_t*>(aDosPath.BeginWriting()), aDosPath.Length());
if (longPathLen == 0) {
return false;
}
// This success check should always be less-than because longPathLen excludes
// the null terminator on success, but includes it in the first call that
// returned the required size.
if (longPathLen < aDosPath.Length()) {
aDosPath.SetLength(longPathLen);
return true;
}
// We shouldn't reach this, but if we do then it's a failure!
return false;
}
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;
DWORD len = 0;
while (true) {
len = GetLogicalDriveStringsW(
len, reinterpret_cast<wchar_t*>(logicalDrives.BeginWriting()));
if (!len) {
return false;
} else if (len > logicalDrives.Length()) {
logicalDrives.SetLength(len);
} else {
break;
}
}
const char16_t* cur = logicalDrives.BeginReading();
const char16_t* end = logicalDrives.EndReading();
nsString targetPath;
targetPath.SetLength(MAX_PATH);
wchar_t driveTemplate[] = L" :";
do {
// 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);
}
}
// Advance to the next NUL character in logicalDrives
while (*cur++);
} while (cur != end);
// 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