bool
HandleToFilename(HANDLE aHandle, const LARGE_INTEGER& aOffset,
nsAString& aFilename)
{
aFilename.Truncate();
// This implementation is nice because it uses fully documented APIs that
// are available on all Windows versions that we support.
nsAutoHandle fileMapping(CreateFileMapping(aHandle, nullptr, PAGE_READONLY,
0, 1, nullptr));
if (!fileMapping) {
return false;
}
ScopedMappedView view(MapViewOfFile(fileMapping, FILE_MAP_READ,
aOffset.HighPart, aOffset.LowPart, 1));
if (!view) {
return false;
}
nsAutoString mappedFilename;
DWORD len = 0;
SetLastError(ERROR_SUCCESS);
do {
mappedFilename.SetLength(mappedFilename.Length() + MAX_PATH);
len = GetMappedFileNameW(GetCurrentProcess(), view,
wwc(mappedFilename.BeginWriting()),
mappedFilename.Length());
} while (!len && GetLastError() == ERROR_INSUFFICIENT_BUFFER);
if (!len) {
return false;
}
mappedFilename.Truncate(len);
return NtPathToDosPath(mappedFilename, aFilename);
}
void
GUIDToString(REFGUID aGuid, nsAString& aOutString)
{
// This buffer length is long enough to hold a GUID string that is formatted
// to include curly braces and dashes.
const int kBufLenWithNul = 39;
aOutString.SetLength(kBufLenWithNul);
int result = StringFromGUID2(aGuid, wwc(aOutString.BeginWriting()), kBufLenWithNul);
MOZ_ASSERT(result);
if (result) {
// Truncate the terminator
aOutString.SetLength(result - 1);
}
}
NS_IMETHODIMP
nsWindowsRegKey::ReadStringValue(const nsAString& aName, nsAString& aResult)
{
if (NS_WARN_IF(!mKey)) {
return NS_ERROR_NOT_INITIALIZED;
}
DWORD type, size;
const nsString& flatName = PromiseFlatString(aName);
LONG rv = RegQueryValueExW(mKey, flatName.get(), 0, &type, nullptr, &size);
if (rv != ERROR_SUCCESS) {
return NS_ERROR_FAILURE;
}
// This must be a string type in order to fetch the value as a string.
// We're being a bit forgiving here by allowing types other than REG_SZ.
if (type != REG_SZ && type != REG_EXPAND_SZ && type != REG_MULTI_SZ) {
return NS_ERROR_FAILURE;
}
// The buffer size must be a multiple of 2.
if (size % 2 != 0) {
return NS_ERROR_UNEXPECTED;
}
if (size == 0) {
aResult.Truncate();
return NS_OK;
}
// |size| may or may not include the terminating null character.
DWORD resultLen = size / 2;
if (!aResult.SetLength(resultLen, mozilla::fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
nsAString::iterator begin;
aResult.BeginWriting(begin);
rv = RegQueryValueExW(mKey, flatName.get(), 0, &type, (LPBYTE)begin.get(),
&size);
if (!aResult.CharAt(resultLen - 1)) {
// The string passed to us had a null terminator in the final position.
aResult.Truncate(resultLen - 1);
}
// Expand the environment variables if needed
if (type == REG_EXPAND_SZ) {
const nsString& flatSource = PromiseFlatString(aResult);
resultLen = ExpandEnvironmentStringsW(flatSource.get(), nullptr, 0);
if (resultLen > 1) {
nsAutoString expandedResult;
// |resultLen| includes the terminating null character
--resultLen;
if (!expandedResult.SetLength(resultLen, mozilla::fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
nsAString::iterator begin;
expandedResult.BeginWriting(begin);
resultLen = ExpandEnvironmentStringsW(flatSource.get(),
wwc(begin.get()),
resultLen + 1);
if (resultLen <= 0) {
rv = ERROR_UNKNOWN_FEATURE;
aResult.Truncate();
} else {
rv = ERROR_SUCCESS;
aResult = expandedResult;
}
} else if (resultLen == 1) {
// It apparently expands to nothing (just a null terminator).
aResult.Truncate();
}
}
return (rv == ERROR_SUCCESS) ? NS_OK : NS_ERROR_FAILURE;
}
