[Fix] Part-1 - LevelDbStore

src/Plugins/LevelDBStore/IO/Data/LevelDB/DB.cs

@@ -10,57 +10,156 @@
 // modifications are permitted.
 
 using System;
-using System.IO;
+using System.Collections;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
 
-namespace Neo.IO.Data.LevelDB
+namespace Neo.IO.Storage.LevelDB
 {
-    public class DB : IDisposable
+    /// <summary>
+    /// A DB is a persistent ordered map from keys to values.
+    /// A DB is safe for concurrent access from multiple threads without any external synchronization.
+    /// </summary>
+    public class DB : LevelDBHandle, IEnumerable<KeyValuePair<byte[], byte[]>>
     {
-        private IntPtr handle;
+        static void Throw(IntPtr error)
+        {
+            Throw(error, msg => new LevelDBException(msg));
+        }
+
+        static void Throw(IntPtr error, Func<string, Exception> exception)
+        {
+            if (error != IntPtr.Zero)
+            {
+                try
+                {
+                    var msg = Marshal.PtrToStringAnsi(error);
+                    throw exception(msg);
+                }
+                finally
+                {
+                    Native.leveldb_free(error);
+                }
+            }
+        }
 
         /// <summary>
-        /// Return true if haven't got valid handle
+        /// Open the database with the specified "name".
         /// </summary>
-        public bool IsDisposed => handle == IntPtr.Zero;
+        public DB(string name, Options options)
+        {
+            Handle = Native.leveldb_open(options.Handle, name, out var error);
+            Throw(error, msg => new UnauthorizedAccessException(msg));
+        }
 
-        private DB(IntPtr handle)
+        public void Close()
         {
-            this.handle = handle;
+            (this as IDisposable).Dispose();
         }
 
-        public void Dispose()
+        /// <summary>
+        /// Set the database entry for "key" to "value".  
+        /// </summary>
+        public void Put(byte[] key, byte[] value)
         {
-            if (handle != IntPtr.Zero)
-            {
-                Native.leveldb_close(handle);
-                handle = IntPtr.Zero;
-            }
+            Put(key, value, WriteOptions.Default);
+        }
+
+        /// <summary>
+        /// Set the database entry for "key" to "value".  
+        /// Note: consider setting new WriteOptions{ Sync = true }.
+        /// </summary>
+        public void Put(byte[] key, byte[] value, WriteOptions options)
+        {
+            Native.leveldb_put(Handle, options.Handle, key, checked((IntPtr)key.LongLength), value, checked((IntPtr)value.LongLength), out var error);
+            Throw(error);
         }
 
-        public void Delete(WriteOptions options, byte[] key)
+        /// <summary>
+        /// Remove the database entry (if any) for "key".  
+        /// It is not an error if "key" did not exist in the database.
+        /// </summary>
+        public void Delete(byte[] key)
         {
-            Native.leveldb_delete(handle, options.handle, key, (UIntPtr)key.Length, out IntPtr error);
-            NativeHelper.CheckError(error);
+            Delete(key, WriteOptions.Default);
         }
 
-        public byte[] Get(ReadOptions options, byte[] key)
+        /// <summary>
+        /// Remove the database entry (if any) for "key".  
+        /// It is not an error if "key" did not exist in the database.
+        /// Note: consider setting new WriteOptions{ Sync = true }.
+        /// </summary>
+        public void Delete(byte[] key, WriteOptions options)
         {
-            IntPtr value = Native.leveldb_get(handle, options.handle, key, (UIntPtr)key.Length, out UIntPtr length, out IntPtr error);
-            try
-            {
-                NativeHelper.CheckError(error);
-                return value.ToByteArray(length);
-            }
-            finally
+            Native.leveldb_delete(Handle, options.Handle, key, checked((nint)key.LongLength), out var error);
+            Throw(error);
+        }
+
+        public void Write(WriteBatch batch)
+        {
+            Write(batch, WriteOptions.Default);
+        }
+
+        public void Write(WriteBatch batch, WriteOptions options)
+        {
+            Native.leveldb_write(Handle, options.Handle, batch.Handle, out var error);
+            Throw(error);
+        }
+
+        /// <summary>
+        /// If the database contains an entry for "key" return the value,
+        /// otherwise return null.
+        /// </summary>
+        public byte[] Get(byte[] key)
+        {
+            return Get(key, ReadOptions.Default);
+        }
+
+        /// <summary>
+        /// If the database contains an entry for "key" return the value,
+        /// otherwise return null.
+        /// </summary>
+        public byte[] Get(byte[] key, ReadOptions options)
+        {
+            var v = Native.leveldb_get(Handle, options.Handle, key, checked((IntPtr)key.LongLength), out var length, out var error);
+            Throw(error);
+
+            if (v != IntPtr.Zero)
             {
-                if (value != IntPtr.Zero) Native.leveldb_free(value);
+                try
+                {
+
+                    var len = (long)length;
+                    int c = 0, si = 0;
+
+                    var bytes = new byte[len];
+
+                    while (si < len)
+                    {
+                        if (len - si > int.MaxValue)
+                            c += int.MaxValue;
+                        else
+                            c += checked((int)(len - si));
+
+                        // Method has a ~2GB limit.
+                        Marshal.Copy(v, bytes, si, c);
+
+                        si += c;
+                    }
+                    return bytes;
+                }
+                finally
+                {
+                    Native.leveldb_free(v);
+                }
             }
+            return null;
         }
 
-        public bool Contains(ReadOptions options, byte[] key)
+        public bool Contains(byte[] key, ReadOptions options)
         {
-            IntPtr value = Native.leveldb_get(handle, options.handle, key, (UIntPtr)key.Length, out _, out IntPtr error);
-            NativeHelper.CheckError(error);
+            var value = Native.leveldb_get(Handle, options.Handle, key, key.Length, out _, out var error);
+            Throw(error);
 
             if (value != IntPtr.Zero)
             {
@@ -71,44 +170,109 @@ public bool Contains(ReadOptions options, byte[] key)
             return false;
         }
 
-        public Snapshot GetSnapshot()
+        /// <summary>
+        /// Return an iterator over the contents of the database.
+        /// The result of CreateIterator is initially invalid (caller must
+        /// call one of the Seek methods on the iterator before using it).
+        /// </summary>
+        public Iterator CreateIterator()
+        {
+            return CreateIterator(ReadOptions.Default);
+        }
+
+        /// <summary>
+        /// Return an iterator over the contents of the database.
+        /// The result of CreateIterator is initially invalid (caller must
+        /// call one of the Seek methods on the iterator before using it).
+        /// </summary>
+        public Iterator CreateIterator(ReadOptions options)
         {
-            return new Snapshot(handle);
+            return new Iterator(Native.leveldb_create_iterator(Handle, options.Handle));
         }
 
-        public Iterator NewIterator(ReadOptions options)
+        /// <summary>
+        /// Return a handle to the current DB state.  
+        /// Iterators and Gets created with this handle will all observe a stable snapshot of the current DB state.  
+        /// </summary>
+        public SnapShot CreateSnapshot()
         {
-            return new Iterator(Native.leveldb_create_iterator(handle, options.handle));
+            return new SnapShot(Native.leveldb_create_snapshot(Handle), this);
         }
 
-        public static DB Open(string name)
+        /// <summary>
+        /// DB implementations can export properties about their state
+        /// via this method.  If "property" is a valid property understood by this
+        /// DB implementation, fills "*value" with its current value and returns
+        /// true.  Otherwise returns false.
+        ///
+        /// Valid property names include:
+        ///
+        ///  "leveldb.num-files-at-level<N>" - return the number of files at level </N>,
+        ///     where <N> is an ASCII representation of a level number (e.g. "0")</N>.
+        ///  "leveldb.stats" - returns a multi-line string that describes statistics
+        ///     about the internal operation of the DB.
+        /// </summary>
+        public string PropertyValue(string name)
         {
-            return Open(name, Options.Default);
+            string result = null;
+            var ptr = Native.leveldb_property_value(Handle, name);
+            if (ptr != IntPtr.Zero)
+            {
+                try
+                {
+                    return Marshal.PtrToStringAnsi(ptr);
+                }
+                finally
+                {
+                    Native.leveldb_free(ptr);
+                }
+            }
+            return result;
         }
 
-        public static DB Open(string name, Options options)
+        /// <summary>
+        /// If a DB cannot be opened, you may attempt to call this method to
+        /// resurrect as much of the contents of the database as possible.
+        /// Some data may be lost, so be careful when calling this function
+        /// on a database that contains important information.
+        /// </summary>
+        public static void Repair(Options options, string name)
+        {
+            Native.leveldb_repair_db(options.Handle, name, out var error);
+            Throw(error);
+        }
+
+        /// <summary>
+        /// Destroy the contents of the specified database.
+        /// Be very careful using this method.
+        /// </summary>
+        public static void Destroy(Options options, string name)
         {
-            IntPtr handle = Native.leveldb_open(options.handle, Path.GetFullPath(name), out IntPtr error);
-            NativeHelper.CheckError(error);
-            return new DB(handle);
+            Native.leveldb_destroy_db(options.Handle, name, out var error);
+            Throw(error);
         }
 
-        public void Put(WriteOptions options, byte[] key, byte[] value)
+        protected override void FreeUnManagedObjects()
         {
-            Native.leveldb_put(handle, options.handle, key, (UIntPtr)key.Length, value, (UIntPtr)value.Length, out IntPtr error);
-            NativeHelper.CheckError(error);
+            if (Handle != default)
+                Native.leveldb_close(Handle);
         }
 
-        public static void Repair(string name, Options options)
+        public IEnumerator<KeyValuePair<byte[], byte[]>> GetEnumerator()
         {
-            Native.leveldb_repair_db(options.handle, Path.GetFullPath(name), out IntPtr error);
-            NativeHelper.CheckError(error);
+            using var sn = CreateSnapshot();
+            using var iterator = CreateIterator(new ReadOptions { Snapshot = sn });
+            iterator.SeekToFirst();
+            while (iterator.IsValid())
+            {
+                yield return new KeyValuePair<byte[], byte[]>(iterator.Key(), iterator.Value());
+                iterator.Next();
+            }
         }
 
-        public void Write(WriteOptions options, WriteBatch write_batch)
+        IEnumerator IEnumerable.GetEnumerator()
         {
-            Native.leveldb_write(handle, options.handle, write_batch.handle, out IntPtr error);
-            NativeHelper.CheckError(error);
+            return GetEnumerator();
         }
     }
 }

src/Plugins/LevelDBStore/IO/Data/LevelDB/Helper.cs

@@ -9,55 +9,34 @@
 // Redistribution and use in source and binary forms with or without
 // modifications are permitted.
 
-using Neo.Persistence;
 using System;
 using System.Collections.Generic;
-using System.Runtime.InteropServices;
 
-namespace Neo.IO.Data.LevelDB
+namespace Neo.IO.Storage.LevelDB
 {
     public static class Helper
     {
-        public static IEnumerable<T> Seek<T>(this DB db, ReadOptions options, byte[] prefix, SeekDirection direction, Func<byte[], byte[], T> resultSelector)
+        public static IEnumerable<(byte[], byte[])> Seek(this DB db, byte[] prefix, ReadOptions options)
         {
-            using Iterator it = db.NewIterator(options);
-            if (direction == SeekDirection.Forward)
-            {
-                for (it.Seek(prefix); it.Valid(); it.Next())
-                    yield return resultSelector(it.Key(), it.Value());
-            }
-            else
-            {
-                // SeekForPrev
+            using var it = db.CreateIterator(options);
 
-                it.Seek(prefix);
-                if (!it.Valid())
-                    it.SeekToLast();
-                else if (it.Key().AsSpan().SequenceCompareTo(prefix) > 0)
-                    it.Prev();
-
-                for (; it.Valid(); it.Prev())
-                    yield return resultSelector(it.Key(), it.Value());
-            }
+            for (it.Seek(prefix); it.IsValid(); it.Next())
+                yield return new(it.Key(), it.Value());
         }
 
-        public static IEnumerable<T> FindRange<T>(this DB db, ReadOptions options, byte[] startKey, byte[] endKey, Func<byte[], byte[], T> resultSelector)
+        public static IEnumerable<(byte[], byte[])> SeekPrev(this DB db, byte[] prefix, ReadOptions options)
         {
-            using Iterator it = db.NewIterator(options);
-            for (it.Seek(startKey); it.Valid(); it.Next())
-            {
-                byte[] key = it.Key();
-                if (key.AsSpan().SequenceCompareTo(endKey) > 0) break;
-                yield return resultSelector(key, it.Value());
-            }
-        }
+            using var it = db.CreateIterator(options);
 
-        internal static byte[] ToByteArray(this IntPtr data, UIntPtr length)
-        {
-            if (data == IntPtr.Zero) return null;
-            byte[] buffer = new byte[(int)length];
-            Marshal.Copy(data, buffer, 0, (int)length);
-            return buffer;
+            it.Seek(prefix);
+
+            if (!it.IsValid())
+                it.SeekToLast();
+            else if (it.Key().AsSpan().SequenceCompareTo(prefix) > 0)
+                it.Prev();
+
+            for (; it.IsValid(); it.Prev())
+                yield return new(it.Key(), it.Value());
         }
     }
 }