Implement stat for Opera.

DiscImageChef.Filesystems/Opera/File.cs

@@ -1,4 +1,7 @@
 using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
 using DiscImageChef.CommonTypes.Structs;
 
 namespace DiscImageChef.Filesystems
@@ -11,6 +14,66 @@ namespace DiscImageChef.Filesystems
 
         public Errno Read(string path, long offset, long size, ref byte[] buf) => throw new NotImplementedException();
 
-        public Errno Stat(string path, out FileEntryInfo stat) => throw new NotImplementedException();
+        public Errno Stat(string path, out FileEntryInfo stat)
+        {
+            stat = null;
+            if(!mounted) return Errno.AccessDenied;
+
+            Errno err = GetFileEntry(path, out DirectoryEntryWithPointers entryWithPointers);
+            if(err != Errno.NoError) return err;
+
+            DirectoryEntry entry = entryWithPointers.entry;
+
+            stat = new FileEntryInfo
+            {
+                Attributes = new FileAttributes(),
+                Blocks     = entry.block_count,
+                BlockSize  = entry.block_size,
+                Length     = entry.byte_count,
+                Inode      = entry.id,
+                Links      = (ulong)entryWithPointers.pointers.Length
+            };
+
+            FileFlags flags = (FileFlags)(entry.flags & FLAGS_MASK);
+
+            if(flags == FileFlags.Directory) stat.Attributes |= FileAttributes.Directory;
+            if(flags == FileFlags.Special) stat.Attributes   |= FileAttributes.Device;
+
+            return Errno.NoError;
+        }
+
+        Errno GetFileEntry(string path, out DirectoryEntryWithPointers entry)
+        {
+            entry = null;
+
+            string cutPath = path.StartsWith("/", StringComparison.Ordinal)
+                                 ? path.Substring(1).ToLower(CultureInfo.CurrentUICulture)
+                                 : path.ToLower(CultureInfo.CurrentUICulture);
+            string[] pieces = cutPath.Split(new[] {'/'}, StringSplitOptions.RemoveEmptyEntries);
+
+            if(pieces.Length == 0) return Errno.InvalidArgument;
+
+            string parentPath = string.Join("/", pieces, 0, pieces.Length - 1);
+
+            if(!directoryCache.TryGetValue(parentPath, out _))
+            {
+                Errno err = ReadDir(parentPath, out _);
+
+                if(err != Errno.NoError) return err;
+            }
+
+            Dictionary<string, DirectoryEntryWithPointers> parent;
+
+            if(pieces.Length == 1) parent = rootDirectoryCache;
+            else if(!directoryCache.TryGetValue(parentPath, out parent)) return Errno.InvalidArgument;
+
+            KeyValuePair<string, DirectoryEntryWithPointers> dirent =
+                parent.FirstOrDefault(t => t.Key.ToLower(CultureInfo.CurrentUICulture) == pieces[pieces.Length - 1]);
+
+            if(string.IsNullOrEmpty(dirent.Key)) return Errno.NoSuchFile;
+
+            entry = dirent.Value;
+            return Errno.NoError;
+        }
     }
 }