private static IEnumerable <string> InternalEnumerateFiles(
string directoryName,
string filePattern,
string fromFilePath,
SearchOption searchOption,
CancellationToken cancellationToken)
{
Stack <string> folders = new Stack <string>();
Stack <string> currentFolderSubFolders = new Stack <string>();
folders.Push(directoryName);
string[] pathSegList = null;
bool passedContinuationToken = false;
int pathSegListIndex = 0;
if (null != fromFilePath)
{
pathSegList = fromFilePath.Split(new char[] { Path.DirectorySeparatorChar });
}
else
{
passedContinuationToken = true;
}
while (folders.Count > 0)
{
string folder = AppendDirectorySeparator(folders.Pop());
Utils.CheckCancellation(cancellationToken);
// Skip non-existent folders
if (!LongPathDirectory.Exists(folder))
{
continue;
}
#if CODE_ACCESS_SECURITY // Only accessible to fully trusted code in non-CAS models
try
{
CheckPathDiscoveryPermission(folder);
}
catch (SecurityException)
{
// Ignore this folder if we have no right to discovery it.
continue;
}
#else // CODE_ACCESS_SECURITY
try
{
// In non-CAS scenarios, it's still important to check for folder accessibility
// since the OS can block access to some paths. Getting files from a location
// will force path discovery checks which will indicate whether or not the user
// is authorized to access the directory.
LongPathDirectory.GetFiles(folder);
}
catch (SecurityException)
{
// Ignore this folder if we have no right to discovery it.
continue;
}
catch (UnauthorizedAccessException)
{
// Ignore this folder if we have no right to discovery it.
continue;
}
#endif // CODE_ACCESS_SECURITY
// Return all files contained directly in this folder (which occur after the continuationTokenFile)
// Only consider the folder if the continuation token is already past or the continuation token may be passed by
// a file within this directory (based on pathSegListIndex and the patSegList.Length)
if (passedContinuationToken ||
(pathSegList.Length - 1 == pathSegListIndex))
{
string continuationTokenFile = null;
if (!passedContinuationToken)
{
continuationTokenFile = pathSegList[pathSegListIndex];
}
// Load files directly under this folder.
foreach (var filePath in LongPathDirectory.EnumerateFileSystemEntries(folder, filePattern, SearchOption.TopDirectoryOnly))
{
Utils.CheckCancellation(cancellationToken);
FileAttributes fileAttributes = FileAttributes.Normal;
string fileName = null;
try
{
fileName = LongPath.GetFileName(filePath);
fileAttributes = LongPathFile.GetAttributes(filePath);
}
// Cross-plat file system accessibility settings may cause exceptions while
// retrieving attributes from inaccessible paths. These paths shold be skipped.
catch (FileNotFoundException) { }
catch (IOException) { }
catch (UnauthorizedAccessException) { }
if (fileName == null)
{
continue;
}
if (FileAttributes.Directory != (fileAttributes & FileAttributes.Directory))
{
if (passedContinuationToken)
{
yield return(LongPath.Combine(folder, fileName));
}
else
{
if (CrossPlatformHelpers.IsLinux)
{
if (!passedContinuationToken)
{
if (string.Equals(fileName, continuationTokenFile, StringComparison.Ordinal))
{
passedContinuationToken = true;
}
}
else
{
yield return(LongPath.Combine(folder, fileName));
}
}
else
{
// Windows file system is case-insensitive; OSX and Linux are case-sensitive
var comparison = CrossPlatformHelpers.IsWindows ? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal;
int compareResult = string.Compare(fileName, continuationTokenFile, comparison);
if (compareResult < 0)
{
// Skip files prior to the continuation token file
continue;
}
passedContinuationToken = true;
if (compareResult > 0)
{
yield return(LongPath.Combine(folder, fileName));
}
}
}
}
}
// Passed folder which continuation token file is under,
// set passedContinuationToken to true.
passedContinuationToken = true;
}
// Next add sub-folders for processing
if (SearchOption.AllDirectories == searchOption)
{
string fromSubfolder = null;
bool passedSubfoler = passedContinuationToken;
if (!passedContinuationToken)
{
fromSubfolder = pathSegList[pathSegListIndex];
pathSegListIndex++;
}
// Add sub-folders.
foreach (var filePath in LongPathDirectory.EnumerateFileSystemEntries(folder, "*", SearchOption.TopDirectoryOnly))
{
Utils.CheckCancellation(cancellationToken);
FileAttributes fileAttributes = FileAttributes.Normal;
string fileName = null;
try
{
fileName = LongPath.GetFileName(filePath);
fileAttributes = LongPathFile.GetAttributes(filePath);
}
// Cross-plat file system accessibility settings may cause exceptions while
// retrieving attributes from inaccessible paths. These paths shold be skipped.
catch (FileNotFoundException) { }
catch (IOException) { }
catch (UnauthorizedAccessException) { }
if (fileName == null)
{
continue;
}
if (FileAttributes.Directory == (fileAttributes & FileAttributes.Directory) &&
!fileName.Equals(@".") &&
!fileName.Equals(@".."))
{
// TODO: Ignore junction point or not. Make it configurable.
if (FileAttributes.ReparsePoint != (fileAttributes & FileAttributes.ReparsePoint))
{
if (passedSubfoler)
{
currentFolderSubFolders.Push(LongPath.Combine(folder, fileName));
}
else
{
if (CrossPlatformHelpers.IsLinux)
{
if (string.Equals(fileName, fromSubfolder, StringComparison.Ordinal))
{
passedSubfoler = true;
currentFolderSubFolders.Push(LongPath.Combine(folder, fileName));
}
}
else
{
// Windows file system is case-insensitive; OSX and Linux are case-sensitive
var comparison = CrossPlatformHelpers.IsWindows ? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal;
int compareResult = string.Compare(fileName, fromSubfolder, comparison);
if (compareResult >= 0)
{
passedSubfoler = true;
currentFolderSubFolders.Push(LongPath.Combine(folder, fileName));
if (compareResult > 0)
{
passedContinuationToken = true;
}
}
}
}
}
}
}
if (currentFolderSubFolders.Count <= 0)
{
passedContinuationToken = true;
}
else
{
while (currentFolderSubFolders.Count > 0)
{
folders.Push(currentFolderSubFolders.Pop());
}
}
}
}
}