/// <inheritdoc />
protected override IEnumerable <UPath> EnumeratePathsImpl(UPath path, string searchPattern, SearchOption searchOption, SearchTarget searchTarget)
{
// Use the search pattern to normalize the path/search pattern
var search = SearchPattern.Parse(ref path, ref searchPattern);
// Query all mounts just once
List <KeyValuePair <UPath, IFileSystem> > mounts;
lock (_mounts)
{
mounts = _mounts.ToList();
}
// Internal method used to retrieve the list of search locations
List <SearchLocation> GetSearchLocations(UPath basePath)
{
var locations = new List <SearchLocation>();
var matchedMount = false;
foreach (var kvp in mounts)
{
// Check if path partially matches a mount name
var remainingPath = GetRemaining(basePath, kvp.Key);
if (!remainingPath.IsNull && remainingPath != UPath.Root)
{
locations.Add(new SearchLocation(this, basePath, remainingPath));
continue;
}
if (!matchedMount)
{
// Check if path fully matches a mount name
remainingPath = GetRemaining(kvp.Key, basePath);
if (!remainingPath.IsNull)
{
matchedMount = true; // don't check other mounts, we don't want to merge them together
if (kvp.Value.DirectoryExists(remainingPath))
{
locations.Add(new SearchLocation(kvp.Value, kvp.Key, remainingPath));
}
}
}
}
if (!matchedMount && NextFileSystem != null && NextFileSystem.DirectoryExists(basePath))
{
locations.Add(new SearchLocation(NextFileSystem, null, basePath));
}
return(locations);
}
var directoryToVisit = new List <UPath>();
directoryToVisit.Add(path);
var entries = new SortedSet <UPath>(UPath.DefaultComparerIgnoreCase);
var sortedDirectories = new SortedSet <UPath>(UPath.DefaultComparerIgnoreCase);
var first = true;
while (directoryToVisit.Count > 0)
{
var pathToVisit = directoryToVisit[0];
directoryToVisit.RemoveAt(0);
var dirIndex = 0;
entries.Clear();
sortedDirectories.Clear();
var locations = GetSearchLocations(pathToVisit);
// Only need to search within one filesystem, no need to sort or do other work
if (locations.Count == 1 && locations[0].FileSystem != this && (!first || searchOption == SearchOption.AllDirectories))
{
var last = locations[0];
foreach (var item in last.FileSystem.EnumeratePaths(last.Path, searchPattern, searchOption, searchTarget))
{
yield return(CombinePrefix(last.Prefix, item));
}
}
else
{
for (var i = locations.Count - 1; i >= 0; i--)
{
var location = locations[i];
var fileSystem = location.FileSystem;
var searchPath = location.Path;
if (fileSystem == this)
{
// List a single part of a mount name, queue it to be visited if needed
var mountPart = new UPath(searchPath.GetFirstDirectory(out _)).ToRelative();
var mountPath = location.Prefix / mountPart;
var isMatching = search.Match(mountPath);
if (isMatching && searchTarget != SearchTarget.File)
{
entries.Add(mountPath);
}
if (searchOption == SearchOption.AllDirectories)
{
sortedDirectories.Add(mountPath);
}
}
else
{
// List files in the mounted filesystems, merged and sorted into one list
foreach (var item in fileSystem.EnumeratePaths(searchPath, "*", SearchOption.TopDirectoryOnly, SearchTarget.Both))
{
var publicName = CombinePrefix(location.Prefix, item);
if (entries.Contains(publicName))
{
continue;
}
var isFile = fileSystem.FileExists(item);
var isDirectory = fileSystem.DirectoryExists(item);
var isMatching = search.Match(publicName);
if (isMatching && ((isFile && searchTarget != SearchTarget.Directory) || (isDirectory && searchTarget != SearchTarget.File)))
{
entries.Add(publicName);
}
if (searchOption == SearchOption.AllDirectories && isDirectory)
{
sortedDirectories.Add(publicName);
}
}
}
}
}
if (first)
{
if (locations.Count == 0 && path != UPath.Root)
{
throw NewDirectoryNotFoundException(path);
}
first = false;
}
// Enqueue directories and respect order
foreach (var nextDir in sortedDirectories)
{
directoryToVisit.Insert(dirIndex++, nextDir);
}
// Return entries
foreach (var entry in entries)
{
yield return(entry);
}
}
}
