Replace ReadDir method with one that uses IDirNode.

Aaru.Core/Sidecar/Files.cs

@@ -47,7 +47,7 @@ public sealed partial class Sidecar
     {
         var contents = new FilesystemContents();
 
-        ErrorNumber ret = filesystem.ReadDir("/", out List<string> dirents);
+        ErrorNumber ret = filesystem.OpenDir("/", out IDirNode node);
 
         if(ret != ErrorNumber.NoError)
             return null;
@@ -55,7 +55,8 @@ public sealed partial class Sidecar
         List<Directory>    directories = new();
         List<ContentsFile> files       = new();
 
-        foreach(string dirent in dirents)
+        while(filesystem.ReadDir(node, out string dirent) == ErrorNumber.NoError &&
+              dirent is not null)
         {
             ret = filesystem.Stat(dirent, out FileEntryInfo stat);
 
@@ -76,6 +77,8 @@ public sealed partial class Sidecar
             files.Add(SidecarFile(filesystem, "", dirent, stat));
         }
 
+        filesystem.CloseDir(node);
+
         if(files.Count > 0)
             contents.Files = files.OrderBy(f => f.Name).ToList();
 
@@ -104,7 +107,7 @@ public sealed partial class Sidecar
             StatusChangeTime = stat.StatusChangeTimeUtc
         };
 
-        ErrorNumber ret = filesystem.ReadDir(path + "/" + filename, out List<string> dirents);
+        ErrorNumber ret = filesystem.OpenDir(path + "/" + filename, out IDirNode node);
 
         if(ret != ErrorNumber.NoError)
             return null;
@@ -112,7 +115,8 @@ public sealed partial class Sidecar
         List<Directory>    directories = new();
         List<ContentsFile> files       = new();
 
-        foreach(string dirent in dirents)
+        while(filesystem.ReadDir(node, out string dirent) == ErrorNumber.NoError &&
+              dirent is not null)
         {
             ret = filesystem.Stat(path + "/" + filename + "/" + dirent, out FileEntryInfo entryStat);
 

Aaru.Filesystems/AppleDOS/Dir.cs

@@ -84,27 +84,23 @@ public sealed partial class AppleDOS
     }
 
     /// <inheritdoc />
-    public ErrorNumber ReadDir(string path, out List<string> contents)
+    public ErrorNumber ReadDir(IDirNode node, out string filename)
     {
-        contents = null;
+        filename = null;
 
         if(!_mounted)
             return ErrorNumber.AccessDenied;
 
-        if(!string.IsNullOrEmpty(path) &&
+        if(node is not AppleDosDirNode mynode)
-           string.Compare(path, "/", StringComparison.OrdinalIgnoreCase) != 0)
+            return ErrorNumber.InvalidArgument;
-            return ErrorNumber.NotSupported;
 
-        contents = _catalogCache.Keys.ToList();
+        if(mynode._position < 0)
+            return ErrorNumber.InvalidArgument;
 
-        if(_debug)
+        if(mynode._position >= mynode._contents.Length)
-        {
+            return ErrorNumber.NoError;
-            contents.Add("$");
-            contents.Add("$Boot");
-            contents.Add("$Vtoc");
-        }
 
-        contents.Sort();
+        filename = mynode._contents[mynode._position++];
 
         return ErrorNumber.NoError;
     }
@@ -121,7 +117,6 @@ public sealed partial class AppleDOS
         return ErrorNumber.NoError;
     }
 
-
     ErrorNumber ReadCatalog()
     {
         var   catalogMs = new MemoryStream();

Aaru.Filesystems/AppleMFS/Dir.cs

@@ -76,30 +76,23 @@ public sealed partial class AppleMFS
     }
 
     /// <inheritdoc />
-    public ErrorNumber ReadDir(string path, out List<string> contents)
+    public ErrorNumber ReadDir(IDirNode node, out string filename)
     {
-        contents = null;
+        filename = null;
 
         if(!_mounted)
             return ErrorNumber.AccessDenied;
 
-        if(!string.IsNullOrEmpty(path) &&
+        if(node is not AppleMfsDirNode mynode)
-           string.Compare(path, "/", StringComparison.OrdinalIgnoreCase) != 0)
+            return ErrorNumber.InvalidArgument;
-            return ErrorNumber.NotSupported;
 
-        contents = _idToFilename.Select(kvp => kvp.Value).ToList();
+        if(mynode._position < 0)
+            return ErrorNumber.InvalidArgument;
 
-        if(_debug)
+        if(mynode._position >= mynode._contents.Length)
-        {
+            return ErrorNumber.NoError;
-            contents.Add("$");
-            contents.Add("$Bitmap");
-            contents.Add("$MDB");
 
-            if(_bootBlocks != null)
+        filename = mynode._contents[mynode._position++];
-                contents.Add("$Boot");
-        }
-
-        contents.Sort();
 
         return ErrorNumber.NoError;
     }

Aaru.Filesystems/CPM/Dir.cs

@@ -31,7 +31,6 @@
 // ****************************************************************************/
 
 using System;
-using System.Collections.Generic;
 using System.Text;
 using Aaru.CommonTypes.Enums;
 using Aaru.CommonTypes.Interfaces;
@@ -64,18 +63,23 @@ public sealed partial class CPM
     }
 
     /// <inheritdoc />
-    public ErrorNumber ReadDir(string path, out List<string> contents)
+    public ErrorNumber ReadDir(IDirNode node, out string filename)
     {
-        contents = null;
+        filename = null;
 
         if(!_mounted)
             return ErrorNumber.AccessDenied;
 
-        if(!string.IsNullOrEmpty(path) &&
+        if(node is not CpmDirNode mynode)
-           string.Compare(path, "/", StringComparison.OrdinalIgnoreCase) != 0)
+            return ErrorNumber.InvalidArgument;
-            return ErrorNumber.NotSupported;
 
-        contents = new List<string>(_dirList);
+        if(mynode._position < 0)
+            return ErrorNumber.InvalidArgument;
+
+        if(mynode._position >= mynode._contents.Length)
+            return ErrorNumber.NoError;
+
+        filename = mynode._contents[mynode._position++];
 
         return ErrorNumber.NoError;
     }

Aaru.Filesystems/FAT/Dir.cs

@@ -413,341 +413,35 @@ public sealed partial class FAT
     }
 
     /// <inheritdoc />
-    /// <summary>Lists contents from a directory.</summary>
+    public ErrorNumber ReadDir(IDirNode node, out string filename)
-    /// <param name="path">Directory path.</param>
-    /// <param name="contents">Directory contents.</param>
-    public ErrorNumber ReadDir(string path, out List<string> contents)
     {
-        contents = null;
+        filename = null;
 
         if(!_mounted)
             return ErrorNumber.AccessDenied;
 
-        if(string.IsNullOrWhiteSpace(path) ||
+        if(node is not FatDirNode mynode)
-           path == "/")
-        {
-            contents = _rootDirectoryCache.Keys.ToList();
-
-            return ErrorNumber.NoError;
-        }
-
-        string cutPath = path.StartsWith("/", StringComparison.Ordinal) ? path[1..].ToLower(_cultureInfo)
-                             : path.ToLower(_cultureInfo);
-
-        if(_directoryCache.TryGetValue(cutPath, out Dictionary<string, CompleteDirectoryEntry> currentDirectory))
-        {
-            contents = currentDirectory.Keys.ToList();
-
-            return ErrorNumber.NoError;
-        }
-
-        string[] pieces = cutPath.Split(new[]
-        {
-            '/'
-        }, StringSplitOptions.RemoveEmptyEntries);
-
-        KeyValuePair<string, CompleteDirectoryEntry> entry =
-            _rootDirectoryCache.FirstOrDefault(t => t.Key.ToLower(_cultureInfo) == pieces[0]);
-
-        if(string.IsNullOrEmpty(entry.Key))
-            return ErrorNumber.NoSuchFile;
-
-        if(!entry.Value.Dirent.attributes.HasFlag(FatAttributes.Subdirectory))
-            return ErrorNumber.NotDirectory;
-
-        string currentPath = pieces[0];
-
-        currentDirectory = _rootDirectoryCache;
-
-        for(int p = 0; p < pieces.Length; p++)
-        {
-            entry = currentDirectory.FirstOrDefault(t => t.Key.ToLower(_cultureInfo) == pieces[p]);
-
-            if(string.IsNullOrEmpty(entry.Key))
-                return ErrorNumber.NoSuchFile;
-
-            if(!entry.Value.Dirent.attributes.HasFlag(FatAttributes.Subdirectory))
-                return ErrorNumber.NotDirectory;
-
-            currentPath = p == 0 ? pieces[0] : $"{currentPath}/{pieces[p]}";
-            uint currentCluster = entry.Value.Dirent.start_cluster;
-
-            if(_fat32)
-                currentCluster += (uint)(entry.Value.Dirent.ea_handle << 16);
-
-            if(_directoryCache.TryGetValue(currentPath, out currentDirectory))
-                continue;
-
-            // Reserved unallocated directory, seen in Atari ST
-            if(currentCluster == 0)
-            {
-                _directoryCache[currentPath] = new Dictionary<string, CompleteDirectoryEntry>();
-                contents                     = new List<string>();
-
-                return ErrorNumber.NoError;
-            }
-
-            uint[] clusters = GetClusters(currentCluster);
-
-            if(clusters is null)
             return ErrorNumber.InvalidArgument;
 
-            byte[] directoryBuffer = new byte[_bytesPerCluster * clusters.Length];
+        if(mynode._position < 0)
+            return ErrorNumber.InvalidArgument;
 
-            for(int i = 0; i < clusters.Length; i++)
+        if(mynode._position >= mynode._entries.Length)
+            return ErrorNumber.NoError;
+
+        CompleteDirectoryEntry entry = mynode._entries[mynode._position];
+
+        filename = _namespace switch
         {
-                ErrorNumber errno = _image.ReadSectors(_firstClusterSector + (clusters[i] * _sectorsPerCluster),
+            Namespace.Ecs when entry.Longname is not null                      => entry.Longname,
-                                                       _sectorsPerCluster, out byte[] buffer);
+            Namespace.Ecs when entry.Longname is null && entry.Lfn is not null => entry.Lfn,
-
+            Namespace.Lfn when entry.Lfn is not null                           => entry.Lfn,
-                if(errno != ErrorNumber.NoError)
+            Namespace.Human when entry.HumanName is not null                   => entry.HumanName,
-                    return errno;
+            Namespace.Os2 when entry.Longname is not null                      => entry.Longname,
-
+            _                                                                  => entry.Shortname
-                Array.Copy(buffer, 0, directoryBuffer, i * _bytesPerCluster, _bytesPerCluster);
-            }
-
-            currentDirectory = new Dictionary<string, CompleteDirectoryEntry>();
-            byte[] lastLfnName     = null;
-            byte   lastLfnChecksum = 0;
-
-            for(int pos = 0; pos < directoryBuffer.Length; pos += Marshal.SizeOf<DirectoryEntry>())
-            {
-                DirectoryEntry dirent =
-                    Marshal.ByteArrayToStructureLittleEndian<DirectoryEntry>(directoryBuffer, pos,
-                                                                             Marshal.SizeOf<DirectoryEntry>());
-
-                if(dirent.filename[0] == DIRENT_FINISHED)
-                    break;
-
-                if(dirent.attributes.HasFlag(FatAttributes.LFN))
-                {
-                    if(_namespace != Namespace.Lfn &&
-                       _namespace != Namespace.Ecs)
-                        continue;
-
-                    LfnEntry lfnEntry =
-                        Marshal.ByteArrayToStructureLittleEndian<LfnEntry>(directoryBuffer, pos,
-                                                                           Marshal.SizeOf<LfnEntry>());
-
-                    int lfnSequence = lfnEntry.sequence & LFN_MASK;
-
-                    if((lfnEntry.sequence & LFN_ERASED) > 0)
-                        continue;
-
-                    if((lfnEntry.sequence & LFN_LAST) > 0)
-                    {
-                        lastLfnName     = new byte[lfnSequence * 26];
-                        lastLfnChecksum = lfnEntry.checksum;
-                    }
-
-                    if(lastLfnName is null)
-                        continue;
-
-                    if(lfnEntry.checksum != lastLfnChecksum)
-                        continue;
-
-                    lfnSequence--;
-
-                    Array.Copy(lfnEntry.name1, 0, lastLfnName, lfnSequence * 26, 10);
-                    Array.Copy(lfnEntry.name2, 0, lastLfnName, (lfnSequence * 26) + 10, 12);
-                    Array.Copy(lfnEntry.name3, 0, lastLfnName, (lfnSequence * 26) + 22, 4);
-
-                    continue;
-                }
-
-                // Not a correct entry
-                if(dirent.filename[0] < DIRENT_MIN &&
-                   dirent.filename[0] != DIRENT_E5)
-                    continue;
-
-                // Self
-                if(_encoding.GetString(dirent.filename).TrimEnd() == ".")
-                    continue;
-
-                // Parent
-                if(_encoding.GetString(dirent.filename).TrimEnd() == "..")
-                    continue;
-
-                // Deleted
-                if(dirent.filename[0] == DIRENT_DELETED)
-                    continue;
-
-                string filename;
-
-                if(dirent.attributes.HasFlag(FatAttributes.VolumeLabel))
-                    continue;
-
-                var completeEntry = new CompleteDirectoryEntry
-                {
-                    Dirent = dirent
         };
 
-                if(_namespace is Namespace.Lfn or Namespace.Ecs &&
+        mynode._position++;
-                   lastLfnName != null)
-                {
-                    byte calculatedLfnChecksum = LfnChecksum(dirent.filename, dirent.extension);
-
-                    if(calculatedLfnChecksum == lastLfnChecksum)
-                    {
-                        filename = StringHandlers.CToString(lastLfnName, Encoding.Unicode, true);
-
-                        completeEntry.Lfn = filename;
-                        lastLfnName       = null;
-                        lastLfnChecksum   = 0;
-                    }
-                }
-
-                if(dirent.filename[0] == DIRENT_E5)
-                    dirent.filename[0] = DIRENT_DELETED;
-
-                string name      = _encoding.GetString(dirent.filename).TrimEnd();
-                string extension = _encoding.GetString(dirent.extension).TrimEnd();
-
-                if(name      == "" &&
-                   extension == "")
-                {
-                    AaruConsole.DebugWriteLine("FAT filesystem", Localization.Found_empty_filename_in_0, path);
-
-                    if(!_debug ||
-                       dirent is { size: > 0, start_cluster: 0 })
-                        continue; // Skip invalid name
-
-                    // If debug, add it
-                    name = ":{EMPTYNAME}:";
-
-                    // Try to create a unique filename with an extension from 000 to 999
-                    for(int uniq = 0; uniq < 1000; uniq++)
-                    {
-                        extension = $"{uniq:D03}";
-
-                        if(!currentDirectory.ContainsKey($"{name}.{extension}"))
-                            break;
-                    }
-
-                    // If we couldn't find it, just skip over
-                    if(currentDirectory.ContainsKey($"{name}.{extension}"))
-                        continue;
-                }
-
-                if(_namespace == Namespace.Nt)
-                {
-                    if(dirent.caseinfo.HasFlag(CaseInfo.LowerCaseExtension))
-                        extension = extension.ToLower(CultureInfo.CurrentCulture);
-
-                    if(dirent.caseinfo.HasFlag(CaseInfo.LowerCaseBasename))
-                        name = name.ToLower(CultureInfo.CurrentCulture);
-                }
-
-                if(extension != "")
-                    filename = name + "." + extension;
-                else
-                    filename = name;
-
-                if(_namespace == Namespace.Human)
-                {
-                    HumanDirectoryEntry humanEntry =
-                        Marshal.ByteArrayToStructureLittleEndian<HumanDirectoryEntry>(directoryBuffer, pos,
-                            Marshal.SizeOf<HumanDirectoryEntry>());
-
-                    completeEntry.HumanDirent = humanEntry;
-
-                    name      = StringHandlers.CToString(humanEntry.name1, _encoding).TrimEnd();
-                    extension = StringHandlers.CToString(humanEntry.extension, _encoding).TrimEnd();
-                    string name2 = StringHandlers.CToString(humanEntry.name2, _encoding).TrimEnd();
-
-                    if(extension != "")
-                        filename = name + name2 + "." + extension;
-                    else
-                        filename = name + name2;
-
-                    completeEntry.HumanName = filename;
-                }
-
-                // Atari ST allows slash AND colon so cannot simply substitute one for the other like in Mac filesystems
-                filename = filename.Replace('/', '\u2215');
-
-                // Using array accessor ensures that repeated entries just get substituted.
-                // Repeated entries are not allowed but some bad implementations (e.g. FAT32.IFS)allow to create them
-                // when using spaces
-                completeEntry.Shortname                    = filename;
-                currentDirectory[completeEntry.ToString()] = completeEntry;
-            }
-
-            // Check OS/2 .LONGNAME
-            if(_eaCache != null                             &&
-               _namespace is Namespace.Os2 or Namespace.Ecs &&
-               !_fat32)
-            {
-                List<KeyValuePair<string, CompleteDirectoryEntry>> filesWithEas =
-                    currentDirectory.Where(t => t.Value.Dirent.ea_handle != 0).ToList();
-
-                foreach(KeyValuePair<string, CompleteDirectoryEntry> fileWithEa in filesWithEas)
-                {
-                    Dictionary<string, byte[]> eas = GetEas(fileWithEa.Value.Dirent.ea_handle);
-
-                    if(eas is null)
-                        continue;
-
-                    if(!eas.TryGetValue("com.microsoft.os2.longname", out byte[] longnameEa))
-                        continue;
-
-                    if(BitConverter.ToUInt16(longnameEa, 0) != EAT_ASCII)
-                        continue;
-
-                    ushort longnameSize = BitConverter.ToUInt16(longnameEa, 2);
-
-                    if(longnameSize + 4 > longnameEa.Length)
-                        continue;
-
-                    byte[] longnameBytes = new byte[longnameSize];
-
-                    Array.Copy(longnameEa, 4, longnameBytes, 0, longnameSize);
-
-                    string longname = StringHandlers.CToString(longnameBytes, _encoding);
-
-                    if(string.IsNullOrWhiteSpace(longname))
-                        continue;
-
-                    // Forward slash is allowed in .LONGNAME, so change it to visually similar division slash
-                    longname = longname.Replace('/', '\u2215');
-
-                    fileWithEa.Value.Longname = longname;
-                    currentDirectory.Remove(fileWithEa.Key);
-                    currentDirectory[fileWithEa.Value.ToString()] = fileWithEa.Value;
-                }
-            }
-
-            // Check FAT32.IFS EAs
-            if(_fat32 || _debug)
-            {
-                List<KeyValuePair<string, CompleteDirectoryEntry>> fat32EaSidecars =
-                    currentDirectory.Where(t => t.Key.EndsWith(FAT32_EA_TAIL, true, _cultureInfo)).ToList();
-
-                foreach(KeyValuePair<string, CompleteDirectoryEntry> sidecar in fat32EaSidecars)
-                {
-                    // No real file this sidecar accompanies
-                    if(!currentDirectory.TryGetValue(sidecar.Key[..^FAT32_EA_TAIL.Length],
-                                                     out CompleteDirectoryEntry fileWithEa))
-                        continue;
-
-                    // If not in debug mode we will consider the lack of EA bitflags to mean the EAs are corrupted or not real
-                    if(!_debug)
-                        if(!fileWithEa.Dirent.caseinfo.HasFlag(CaseInfo.NormalEaOld) &&
-                           !fileWithEa.Dirent.caseinfo.HasFlag(CaseInfo.CriticalEa)  &&
-                           !fileWithEa.Dirent.caseinfo.HasFlag(CaseInfo.NormalEa)    &&
-                           !fileWithEa.Dirent.caseinfo.HasFlag(CaseInfo.CriticalEa))
-                            continue;
-
-                    fileWithEa.Fat32Ea = sidecar.Value.Dirent;
-
-                    if(!_debug)
-                        currentDirectory.Remove(sidecar.Key);
-                }
-            }
-
-            _directoryCache.Add(currentPath, currentDirectory);
-        }
-
-        contents = currentDirectory?.Keys.ToList();
 
         return ErrorNumber.NoError;
     }

Aaru.Filesystems/FAT/File.cs

@@ -313,10 +313,12 @@ public sealed partial class FAT
 
         if(!_directoryCache.TryGetValue(parentPath, out _))
         {
-            ErrorNumber err = ReadDir(parentPath, out _);
+            ErrorNumber err = OpenDir(parentPath, out IDirNode node);
 
             if(err != ErrorNumber.NoError)
                 return err;
+
+            CloseDir(node);
         }
 
         Dictionary<string, CompleteDirectoryEntry> parent;

Aaru.Filesystems/FATX/Dir.cs

@@ -167,112 +167,26 @@ public sealed partial class XboxFatPlugin
     }
 
     /// <inheritdoc />
-    public ErrorNumber ReadDir(string path, out List<string> contents)
+    public ErrorNumber ReadDir(IDirNode node, out string filename)
     {
-        contents = null;
+        filename = null;
 
         if(!_mounted)
             return ErrorNumber.AccessDenied;
 
-        if(string.IsNullOrWhiteSpace(path) ||
+        if(node is not FatxDirNode mynode)
-           path == "/")
-        {
-            contents = _rootDirectory.Keys.ToList();
-
-            return ErrorNumber.NoError;
-        }
-
-        string cutPath = path.StartsWith('/') ? path[1..].ToLower(_cultureInfo) : path.ToLower(_cultureInfo);
-
-        if(_directoryCache.TryGetValue(cutPath, out Dictionary<string, DirectoryEntry> currentDirectory))
-        {
-            contents = currentDirectory.Keys.ToList();
-
-            return ErrorNumber.NoError;
-        }
-
-        string[] pieces = cutPath.Split(new[]
-        {
-            '/'
-        }, StringSplitOptions.RemoveEmptyEntries);
-
-        KeyValuePair<string, DirectoryEntry> entry =
-            _rootDirectory.FirstOrDefault(t => t.Key.ToLower(_cultureInfo) == pieces[0]);
-
-        if(string.IsNullOrEmpty(entry.Key))
-            return ErrorNumber.NoSuchFile;
-
-        if(!entry.Value.attributes.HasFlag(Attributes.Directory))
-            return ErrorNumber.NotDirectory;
-
-        string currentPath = pieces[0];
-
-        currentDirectory = _rootDirectory;
-
-        for(int p = 0; p < pieces.Length; p++)
-        {
-            entry = currentDirectory.FirstOrDefault(t => t.Key.ToLower(_cultureInfo) == pieces[p]);
-
-            if(string.IsNullOrEmpty(entry.Key))
-                return ErrorNumber.NoSuchFile;
-
-            if(!entry.Value.attributes.HasFlag(Attributes.Directory))
-                return ErrorNumber.NotDirectory;
-
-            currentPath = p == 0 ? pieces[0] : $"{currentPath}/{pieces[p]}";
-            uint currentCluster = entry.Value.firstCluster;
-
-            if(_directoryCache.TryGetValue(currentPath, out currentDirectory))
-                continue;
-
-            uint[] clusters = GetClusters(currentCluster);
-
-            if(clusters is null)
             return ErrorNumber.InvalidArgument;
 
-            byte[] directoryBuffer = new byte[_bytesPerCluster * clusters.Length];
+        if(mynode._position < 0)
+            return ErrorNumber.InvalidArgument;
 
-            for(int i = 0; i < clusters.Length; i++)
+        if(mynode._position >= mynode._entries.Length)
-            {
+            return ErrorNumber.NoError;
-                ErrorNumber errno =
-                    _imagePlugin.ReadSectors(_firstClusterSector + ((clusters[i] - 1) * _sectorsPerCluster),
-                                             _sectorsPerCluster, out byte[] buffer);
 
-                if(errno != ErrorNumber.NoError)
+        filename = _encoding.GetString(mynode._entries[mynode._position].filename, 0,
-                    return errno;
+                                       mynode._entries[mynode._position].filenameSize);
 
-                Array.Copy(buffer, 0, directoryBuffer, i * _bytesPerCluster, _bytesPerCluster);
+        mynode._position++;
-            }
-
-            currentDirectory = new Dictionary<string, DirectoryEntry>();
-
-            int pos = 0;
-
-            while(pos < directoryBuffer.Length)
-            {
-                DirectoryEntry dirent = _littleEndian
-                                            ? Marshal.ByteArrayToStructureLittleEndian<DirectoryEntry>(directoryBuffer,
-                                                pos, Marshal.SizeOf<DirectoryEntry>())
-                                            : Marshal.ByteArrayToStructureBigEndian<DirectoryEntry>(directoryBuffer,
-                                                pos, Marshal.SizeOf<DirectoryEntry>());
-
-                pos += Marshal.SizeOf<DirectoryEntry>();
-
-                if(dirent.filenameSize is UNUSED_DIRENTRY or FINISHED_DIRENTRY)
-                    break;
-
-                if(dirent.filenameSize is DELETED_DIRENTRY or > MAX_FILENAME)
-                    continue;
-
-                string filename = _encoding.GetString(dirent.filename, 0, dirent.filenameSize);
-
-                currentDirectory.Add(filename, dirent);
-            }
-
-            _directoryCache.Add(currentPath, currentDirectory);
-        }
-
-        contents = currentDirectory?.Keys.ToList();
 
         return ErrorNumber.NoError;
     }

Aaru.Filesystems/FATX/File.cs

@@ -276,11 +276,13 @@ public sealed partial class XboxFatPlugin
 
         string parentPath = string.Join("/", pieces, 0, pieces.Length - 1);
 
-        ErrorNumber err = ReadDir(parentPath, out _);
+        ErrorNumber err = OpenDir(parentPath, out IDirNode node);
 
         if(err != ErrorNumber.NoError)
             return err;
 
+        CloseDir(node);
+
         Dictionary<string, DirectoryEntry> parent;
 
         if(pieces.Length == 1)

Aaru.Filesystems/ISO9660/Dir.cs

@@ -150,89 +150,41 @@ public sealed partial class ISO9660
     }
 
     /// <inheritdoc />
-    public ErrorNumber ReadDir(string path, out List<string> contents)
+    public ErrorNumber ReadDir(IDirNode node, out string filename)
     {
-        contents = null;
+        filename = null;
 
         if(!_mounted)
             return ErrorNumber.AccessDenied;
 
-        if(string.IsNullOrWhiteSpace(path) ||
+        if(node is not Iso9660DirNode mynode)
-           path == "/")
-        {
-            contents = GetFilenames(_rootDirectoryCache);
-
-            return ErrorNumber.NoError;
-        }
-
-        string cutPath = path.StartsWith("/", StringComparison.Ordinal)
-                             ? path[1..].ToLower(CultureInfo.CurrentUICulture)
-                             : path.ToLower(CultureInfo.CurrentUICulture);
-
-        if(_directoryCache.TryGetValue(cutPath, out Dictionary<string, DecodedDirectoryEntry> currentDirectory))
-        {
-            contents = currentDirectory.Keys.ToList();
-
-            return ErrorNumber.NoError;
-        }
-
-        string[] pieces = cutPath.Split(new[]
-        {
-            '/'
-        }, StringSplitOptions.RemoveEmptyEntries);
-
-        KeyValuePair<string, DecodedDirectoryEntry> entry =
-            _rootDirectoryCache.FirstOrDefault(t => t.Key.ToLower(CultureInfo.CurrentUICulture) == pieces[0]);
-
-        if(string.IsNullOrEmpty(entry.Key))
-            return ErrorNumber.NoSuchFile;
-
-        if(!entry.Value.Flags.HasFlag(FileFlags.Directory))
-            return ErrorNumber.NotDirectory;
-
-        string currentPath = pieces[0];
-
-        currentDirectory = _rootDirectoryCache;
-
-        for(int p = 0; p < pieces.Length; p++)
-        {
-            entry = currentDirectory.FirstOrDefault(t => t.Key.ToLower(CultureInfo.CurrentUICulture) == pieces[p]);
-
-            if(string.IsNullOrEmpty(entry.Key))
-                return ErrorNumber.NoSuchFile;
-
-            if(!entry.Value.Flags.HasFlag(FileFlags.Directory))
-                return ErrorNumber.NotDirectory;
-
-            currentPath = p == 0 ? pieces[0] : $"{currentPath}/{pieces[p]}";
-
-            if(_directoryCache.TryGetValue(currentPath, out currentDirectory))
-                continue;
-
-            if(entry.Value.Extents.Count == 0)
             return ErrorNumber.InvalidArgument;
 
-            currentDirectory = _cdi
+        if(mynode._position < 0)
-                                   ? DecodeCdiDirectory(entry.Value.Extents[0].extent + entry.Value.XattrLength,
+            return ErrorNumber.InvalidArgument;
-                                                        entry.Value.Extents[0].size)
-                                   : _highSierra
-                                       ? DecodeHighSierraDirectory(entry.Value.Extents[0].extent + entry.Value.XattrLength,
-                                                                   entry.Value.Extents[0].size)
-                                       : DecodeIsoDirectory(entry.Value.Extents[0].extent + entry.Value.XattrLength,
-                                                            entry.Value.Extents[0].size);
 
-            if(_usePathTable)
+        if(mynode._position >= mynode._entries.Length)
-                foreach(DecodedDirectoryEntry subDirectory in _cdi
+            return ErrorNumber.NoError;
-                                                                  ? GetSubdirsFromCdiPathTable(currentPath)
-                                                                  : _highSierra
-                                                                      ? GetSubdirsFromHighSierraPathTable(currentPath)
-                                                                      : GetSubdirsFromIsoPathTable(currentPath))
-                    currentDirectory[subDirectory.Filename] = subDirectory;
 
-            _directoryCache.Add(currentPath, currentDirectory);
+        switch(_namespace)
+        {
+            case Namespace.Normal:
+                filename = mynode._entries[mynode._position].Filename.EndsWith(";1", StringComparison.Ordinal)
+                               ? mynode._entries[mynode._position].Filename[..^2]
+                               : mynode._entries[mynode._position].Filename;
+
+                break;
+            case Namespace.Vms:
+            case Namespace.Joliet:
+            case Namespace.Rrip:
+            case Namespace.Romeo:
+                filename = mynode._entries[mynode._position].Filename;
+
+                break;
+            default: return ErrorNumber.InvalidArgument;
         }
 
-        contents = GetFilenames(currentDirectory);
+        mynode._position++;
 
         return ErrorNumber.NoError;
     }
@@ -249,31 +201,6 @@ public sealed partial class ISO9660
         return ErrorNumber.NoError;
     }
 
-    List<string> GetFilenames(Dictionary<string, DecodedDirectoryEntry> dirents)
-    {
-        List<string> contents = new();
-
-        foreach(DecodedDirectoryEntry entry in dirents.Values)
-            switch(_namespace)
-            {
-                case Namespace.Normal:
-                    contents.Add(entry.Filename.EndsWith(";1", StringComparison.Ordinal) ? entry.Filename[..^2]
-                                     : entry.Filename);
-
-                    break;
-                case Namespace.Vms:
-                case Namespace.Joliet:
-                case Namespace.Rrip:
-                case Namespace.Romeo:
-                    contents.Add(entry.Filename);
-
-                    break;
-                default: throw new ArgumentOutOfRangeException();
-            }
-
-        return contents;
-    }
-
     Dictionary<string, DecodedDirectoryEntry> DecodeCdiDirectory(ulong start, uint size)
     {
         Dictionary<string, DecodedDirectoryEntry> entries  = new();

Aaru.Filesystems/ISO9660/File.cs

@@ -481,10 +481,12 @@ public sealed partial class ISO9660
 
         if(!_directoryCache.TryGetValue(parentPath, out _))
         {
-            ErrorNumber err = ReadDir(parentPath, out _);
+            ErrorNumber err = OpenDir(parentPath, out IDirNode node);
 
             if(err != ErrorNumber.NoError)
                 return err;
+
+            CloseDir(node);
         }
 
         Dictionary<string, DecodedDirectoryEntry> parent;

Aaru.Filesystems/LisaFS/Dir.cs

@@ -96,37 +96,23 @@ public sealed partial class LisaFS
     }
 
     /// <inheritdoc />
-    public ErrorNumber ReadDir(string path, out List<string> contents)
+    public ErrorNumber ReadDir(IDirNode node, out string filename)
     {
-        contents = null;
+        filename = null;
-        ErrorNumber error = LookupFileId(path, out short fileId, out bool isDir);
 
-        if(error != ErrorNumber.NoError)
+        if(!_mounted)
-            return error;
+            return ErrorNumber.AccessDenied;
 
-        if(!isDir)
+        if(node is not LisaDirNode mynode)
-            return ErrorNumber.NotDirectory;
+            return ErrorNumber.InvalidArgument;
 
-        /*List<CatalogEntry> catalog;
+        if(mynode._position < 0)
-        error = ReadCatalog(fileId, out catalog);
+            return ErrorNumber.InvalidArgument;
-        if(error != ErrorNumber.NoError)
-            return error;*/
 
-        ReadDir(fileId, out contents);
+        if(mynode._position >= mynode._contents.Length)
+            return ErrorNumber.NoError;
 
-        // On debug add system files as readable files
+        filename = mynode._contents[mynode._position++];
-        // Syntax similar to NTFS
-        if(_debug && fileId == DIRID_ROOT)
-        {
-            contents.Add("$MDDF");
-            contents.Add("$Boot");
-            contents.Add("$Loader");
-            contents.Add("$Bitmap");
-            contents.Add("$S-Record");
-            contents.Add("$");
-        }
-
-        contents.Sort();
 
         return ErrorNumber.NoError;
     }

Aaru.Filesystems/Opera/Dir.cs

@@ -130,74 +130,23 @@ public sealed partial class OperaFS
     }
 
     /// <inheritdoc />
-    public ErrorNumber ReadDir(string path, out List<string> contents)
+    public ErrorNumber ReadDir(IDirNode node, out string filename)
     {
-        contents = null;
+        filename = null;
 
         if(!_mounted)
             return ErrorNumber.AccessDenied;
 
-        if(string.IsNullOrWhiteSpace(path) ||
+        if(node is not OperaDirNode mynode)
-           path == "/")
-        {
-            contents = _rootDirectoryCache.Keys.ToList();
-
-            return ErrorNumber.NoError;
-        }
-
-        string cutPath = path.StartsWith("/", StringComparison.Ordinal)
-                             ? path[1..].ToLower(CultureInfo.CurrentUICulture)
-                             : path.ToLower(CultureInfo.CurrentUICulture);
-
-        if(_directoryCache.TryGetValue(cutPath, out Dictionary<string, DirectoryEntryWithPointers> currentDirectory))
-        {
-            contents = currentDirectory.Keys.ToList();
-
-            return ErrorNumber.NoError;
-        }
-
-        string[] pieces = cutPath.Split(new[]
-        {
-            '/'
-        }, StringSplitOptions.RemoveEmptyEntries);
-
-        KeyValuePair<string, DirectoryEntryWithPointers> entry =
-            _rootDirectoryCache.FirstOrDefault(t => t.Key.ToLower(CultureInfo.CurrentUICulture) == pieces[0]);
-
-        if(string.IsNullOrEmpty(entry.Key))
-            return ErrorNumber.NoSuchFile;
-
-        if((entry.Value.Entry.flags & FLAGS_MASK) != (int)FileFlags.Directory)
-            return ErrorNumber.NotDirectory;
-
-        string currentPath = pieces[0];
-
-        currentDirectory = _rootDirectoryCache;
-
-        for(int p = 0; p < pieces.Length; p++)
-        {
-            entry = currentDirectory.FirstOrDefault(t => t.Key.ToLower(CultureInfo.CurrentUICulture) == pieces[p]);
-
-            if(string.IsNullOrEmpty(entry.Key))
-                return ErrorNumber.NoSuchFile;
-
-            if((entry.Value.Entry.flags & FLAGS_MASK) != (int)FileFlags.Directory)
-                return ErrorNumber.NotDirectory;
-
-            currentPath = p == 0 ? pieces[0] : $"{currentPath}/{pieces[p]}";
-
-            if(_directoryCache.TryGetValue(currentPath, out currentDirectory))
-                continue;
-
-            if(entry.Value.Pointers.Length < 1)
             return ErrorNumber.InvalidArgument;
 
-            currentDirectory = DecodeDirectory((int)entry.Value.Pointers[0]);
+        if(mynode._position < 0)
+            return ErrorNumber.InvalidArgument;
 
-            _directoryCache.Add(currentPath, currentDirectory);
+        if(mynode._position >= mynode._contents.Length)
-        }
+            return ErrorNumber.NoError;
 
-        contents = currentDirectory?.Keys.ToList();
+        filename = mynode._contents[mynode._position++];
 
         return ErrorNumber.NoError;
     }

Aaru.Filesystems/Opera/File.cs

@@ -212,10 +212,12 @@ public sealed partial class OperaFS
 
         if(!_directoryCache.TryGetValue(parentPath, out _))
         {
-            ErrorNumber err = ReadDir(parentPath, out _);
+            ErrorNumber err = OpenDir(parentPath, out IDirNode node);
 
             if(err != ErrorNumber.NoError)
                 return err;
+
+            CloseDir(node);
         }
 
         Dictionary<string, DirectoryEntryWithPointers> parent;

Aaru.Filesystems/UCSDPascal/Dir.cs

@@ -76,26 +76,23 @@ public sealed partial class PascalPlugin
     }
 
     /// <inheritdoc />
-    public ErrorNumber ReadDir(string path, out List<string> contents)
+    public ErrorNumber ReadDir(IDirNode node, out string filename)
     {
-        contents = null;
+        filename = null;
 
         if(!_mounted)
             return ErrorNumber.AccessDenied;
 
-        if(!string.IsNullOrEmpty(path) &&
+        if(node is not PascalDirNode mynode)
-           string.Compare(path, "/", StringComparison.OrdinalIgnoreCase) != 0)
+            return ErrorNumber.InvalidArgument;
-            return ErrorNumber.NotSupported;
 
-        contents = _fileEntries.Select(ent => StringHandlers.PascalToString(ent.Filename, _encoding)).ToList();
+        if(mynode._position < 0)
+            return ErrorNumber.InvalidArgument;
 
-        if(_debug)
+        if(mynode._position >= mynode._contents.Length)
-        {
+            return ErrorNumber.NoError;
-            contents.Add("$");
-            contents.Add("$Boot");
-        }
 
-        contents.Sort();
+        filename = mynode._contents[mynode._position++];
 
         return ErrorNumber.NoError;
     }

Aaru.Gui/ViewModels/Panels/SubdirectoryViewModel.cs

@@ -67,7 +67,7 @@ public sealed class SubdirectoryViewModel
         _model              = model;
         _view               = view;
 
-        ErrorNumber errno = model.Plugin.ReadDir(model.Path, out List<string> dirents);
+        ErrorNumber errno = model.Plugin.OpenDir(model.Path, out IDirNode node);
 
         if(errno != ErrorNumber.NoError)
         {
@@ -80,7 +80,8 @@ public sealed class SubdirectoryViewModel
             return;
         }
 
-        foreach(string dirent in dirents)
+        while(model.Plugin.ReadDir(node, out string dirent) == ErrorNumber.NoError &&
+              dirent is not null)
         {
             errno = model.Plugin.Stat(model.Path + "/" + dirent, out FileEntryInfo stat);
 
@@ -112,6 +113,8 @@ public sealed class SubdirectoryViewModel
                 Stat = stat
             });
         }
+
+        model.Plugin.CloseDir(node);
     }
 
     public ObservableCollection<FileModel> Entries             { get; }

Aaru.Tests/Filesystems/ReadOnlyFilesystemTest.cs

@@ -267,12 +267,13 @@ public abstract class ReadOnlyFilesystemTest : FilesystemTest
             path = "";
 
         Dictionary<string, FileData> children = new();
-        fs.ReadDir(path, out List<string> contents);
+        ErrorNumber                  ret      = fs.OpenDir(path, out IDirNode node);
 
-        if(contents is null)
+        if(ret != ErrorNumber.NoError)
             return children;
 
-        foreach(string child in contents)
+        while(fs.ReadDir(node, out string child) == ErrorNumber.NoError &&
+              child is not null)
         {
             string childPath = $"{path}/{child}";
             fs.Stat(childPath, out FileEntryInfo stat);
@@ -303,6 +304,8 @@ public abstract class ReadOnlyFilesystemTest : FilesystemTest
             children[child] = data;
         }
 
+        fs.CloseDir(node);
+
         return children;
     }
 
@@ -351,7 +354,7 @@ public abstract class ReadOnlyFilesystemTest : FilesystemTest
     {
         currentDepth++;
         nextLevels = new List<NextLevel>();
-        ErrorNumber ret = fs.ReadDir(path, out List<string> contents);
+        ErrorNumber ret = fs.OpenDir(path, out IDirNode node);
 
         // Directory is not readable, probably filled the volume, just ignore it
         if(ret == ErrorNumber.InvalidArgument)
@@ -364,6 +367,14 @@ public abstract class ReadOnlyFilesystemTest : FilesystemTest
         if(ret != ErrorNumber.NoError)
             return;
 
+        List<string> contents = new();
+
+        while(fs.ReadDir(node, out string filename) == ErrorNumber.NoError &&
+              filename is not null)
+            contents.Add(filename);
+
+        fs.CloseDir(node);
+
         if(children.Count == 0 &&
            contents.Count == 0)
             return;

Aaru.Tests/Issues/FsExtractHashIssueTest.cs

@@ -162,12 +162,13 @@ public abstract class FsExtractHashIssueTest
         if(path.StartsWith('/'))
             path = path[1..];
 
-        ErrorNumber error = fs.ReadDir(path, out List<string> directory);
+        ErrorNumber error = fs.OpenDir(path, out IDirNode node);
 
         Assert.AreEqual(ErrorNumber.NoError, error,
                         string.Format(Localization.Error_0_reading_root_directory_0, error.ToString()));
 
-        foreach(string entry in directory)
+        while(fs.ReadDir(node, out string entry) == ErrorNumber.NoError &&
+              entry is not null)
         {
             error = fs.Stat(path + "/" + entry, out FileEntryInfo stat);
 
@@ -273,5 +274,7 @@ public abstract class FsExtractHashIssueTest
             Assert.AreEqual(fileData.Md5, calculatedMd5,
                             string.Format(Localization.Invalid_checksum_for_file_0, path + "/" + entry));
         }
+
+        fs.CloseDir(node);
     }
 }

Aaru.Tests/Issues/FsExtractIssueTest.cs

@@ -129,12 +129,13 @@ public abstract class FsExtractIssueTest
         if(path.StartsWith('/'))
             path = path[1..];
 
-        ErrorNumber error = fs.ReadDir(path, out List<string> directory);
+        ErrorNumber error = fs.OpenDir(path, out IDirNode node);
 
         Assert.AreEqual(ErrorNumber.NoError, error,
                         string.Format(Localization.Error_0_reading_root_directory_0, error.ToString()));
 
-        foreach(string entry in directory)
+        while(fs.ReadDir(node, out string entry) == ErrorNumber.NoError &&
+              entry is not null)
         {
             error = fs.Stat(path + "/" + entry, out FileEntryInfo stat);
 
@@ -183,5 +184,7 @@ public abstract class FsExtractIssueTest
                             string.Format(Localization.Error_0_reading_file_1, readBytes, stat.Length,
                                           path + "/" + entry));
         }
+
+        fs.CloseDir(node);
     }
 }

Aaru/Commands/Filesystem/ExtractFiles.cs

@@ -394,7 +394,7 @@ sealed class ExtractFilesCommand : Command
         if(path.StartsWith('/'))
             path = path[1..];
 
-        ErrorNumber error = fs.ReadDir(path, out List<string> directory);
+        ErrorNumber error = fs.OpenDir(path, out IDirNode node);
 
         if(error != ErrorNumber.NoError)
         {
@@ -403,7 +403,8 @@ sealed class ExtractFilesCommand : Command
             return;
         }
 
-        foreach(string entry in directory)
+        while(fs.ReadDir(node, out string entry) == ErrorNumber.NoError &&
+              entry is not null)
         {
             FileEntryInfo stat = new();
 
@@ -679,5 +680,7 @@ sealed class ExtractFilesCommand : Command
             else
                 AaruConsole.ErrorWriteLine(UI.Error_reading_file_0, Markup.Escape(entry));
         }
+
+        fs.CloseDir(node);
     }
 }

Aaru/Commands/Filesystem/Ls.cs

@@ -354,7 +354,7 @@ sealed class LsCommand : Command
     static void ListFilesInDir(string path, [NotNull] IReadOnlyFilesystem fs, bool longFormat)
     {
         ErrorNumber error = ErrorNumber.InvalidArgument;
-        List<string> directory = new();
+        IDirNode    node  = null;
 
         if(path.StartsWith('/'))
             path = path[1..];
@@ -365,7 +365,7 @@ sealed class LsCommand : Command
         Core.Spectre.ProgressSingleSpinner(ctx =>
         {
             ctx.AddTask(UI.Reading_directory).IsIndeterminate();
-            error = fs.ReadDir(path, out directory);
+            error = fs.OpenDir(path, out node);
         });
 
         if(error != ErrorNumber.NoError)
@@ -377,19 +377,19 @@ sealed class LsCommand : Command
 
         Dictionary<string, FileEntryInfo> stats = new();
 
-        AnsiConsole.Progress().AutoClear(true).HideCompleted(true).
+        Core.Spectre.ProgressSingleSpinner(ctx =>
-                    Columns(new TaskDescriptionColumn(), new ProgressBarColumn(), new PercentageColumn()).Start(ctx =>
         {
-                        ProgressTask task = ctx.AddTask(UI.Retrieving_file_information);
+            ctx.AddTask(UI.Retrieving_file_information).IsIndeterminate();
-                        task.MaxValue = directory.Count;
 
-                        foreach(string entry in directory)
+            while(fs.ReadDir(node, out string entry) == ErrorNumber.NoError &&
+                  entry is not null)
             {
-                            task.Increment(1);
                 fs.Stat(path + "/" + entry, out FileEntryInfo stat);
 
                 stats.Add(entry, stat);
             }
+
+            fs.CloseDir(node);
         });
 
         foreach(KeyValuePair<string, FileEntryInfo> entry in