internal static IEnumerable <FileSystemInfo> Traverse(DirectoryInfo root, Segment[] segments, int segmentIndex,
TraverseOptions options)
{
if (segmentIndex == segments.Length)
{
return(options.EmitDirectories
? Enumerable.Repeat <FileSystemInfo>(root, 1)
: emptyFileSystemInfoArray);
}
var segment = segments[segmentIndex];
switch (segment)
{
case DirectorySegment directorySegment:
{
var filesToEmit =
(options.EmitFiles && segmentIndex == segments.Length - 1)
? options.GetFiles(root).Where(file => directorySegment.MatchesSegment(file.Name, options.CaseSensitive)).Cast <FileSystemInfo>()
: emptyFileSystemInfoArray;
var dirSegmentItems = from directory in options.GetDirectories(root)
where directorySegment.MatchesSegment(directory.Name, options.CaseSensitive)
from item in Traverse(directory, segments, segmentIndex + 1, options)
select item;
return(filesToEmit.Concat(dirSegmentItems));
}
case DirectoryWildcard _:
{
var filesToEmit =
(options.EmitFiles && segmentIndex == segments.Length - 1)
? options.GetFiles(root).Cast <FileSystemInfo>()
: emptyFileSystemInfoArray;
// match zero path segments, consuming DirectoryWildcard
var zeroMatch = Traverse(root, segments, segmentIndex + 1, options);
// match consume 1 path segment but not the Wildcard
var files = from directory in options.GetDirectories(root)
from item in Traverse(directory, segments, segmentIndex, options)
select item;
return(filesToEmit.Concat(zeroMatch).Concat(files));
}
default:
return(emptyFileSystemInfoArray);
}
}
public IEnumerator <FileSystemInfo> GetEnumerator()
{
var roots = new List <DirectoryInfo>();
var rootCache = new List <DirectoryInfo>();
roots.AddRange(_originalRoots);
var segmentsLength = _segments.Length;
var nextSegmentRoots = new List <DirectoryInfo>();
var segmentIndex = 0;
var emitDirectories = _options.EmitDirectories;
var emitFiles = _options.EmitFiles;
var cache = new HashSet <string>();
void Swap(ref List <DirectoryInfo> other)
{
var swap = roots;
roots = other;
other = swap;
}
while (true)
{
// no more segments. return all current roots
var noMoreSegments = segmentIndex == segmentsLength;
if (emitDirectories && noMoreSegments)
{
foreach (var info in roots.Where(info => !cache.Contains(info.FullName)))
{
cache.Add(info.FullName);
yield return(info);
}
}
// no more roots or no more segments, go to next segment
if (roots.Count == 0 || noMoreSegments)
{
roots.Clear();
if (nextSegmentRoots.Count > 0)
{
Swap(ref nextSegmentRoots);
segmentIndex++;
continue;
}
yield break;
}
var segment = _segments[segmentIndex];
var onLastSegment = segmentIndex == segmentsLength - 1;
if (emitFiles && onLastSegment)
{
var allFiles = from job in roots
let children = _options.GetFiles(job)
from file in FilesMatchingSegment(children, segment, _options.CaseSensitive)
select file;
foreach (var info in allFiles)
{
if (!cache.Contains(info.FullName))
{
cache.Add(info.FullName);
yield return(info);
}
}
}
rootCache.Clear();
rootCache.AddRange(roots.SelectMany(job => JobsMatchingSegment(nextSegmentRoots, job, segment)));
Swap(ref rootCache);
}
}
