Snapshot.cs

//  leveldb-sharp
//
//  Copyright (c) 2011 The LevelDB Authors
//  Copyright (c) 2013, Mirco Bauer <meebey@meebey.net>
//  All rights reserved.
//
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//  modification, are permitted provided that the following conditions are
//  met:
//
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//       notice, this list of conditions and the following disclaimer.
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//       distribution.
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//
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using System;

namespace LevelDB
{
    /// <summary>
    /// Snapshots provide consistent read-only views over the entire state of
    /// the key-value store. ReadOptions.Snapshot may be non-NULL to indicate
    /// that a read should operate on a particular version of the DB state.
    /// If ReadOptions.Snapshot is NULL, the read will operate on an implicit
    /// snapshot of the current state.
    /// </summary>
    public class Snapshot
    {
        /// <summary>
        /// Native handle
        /// </summary>
        public IntPtr Handle { get; private set; }
        DB DB { get; set; }

        public Snapshot(DB db)
        {
            if (db == null) {
                throw new ArgumentNullException("db");
            }

            DB = db;
            Handle = Native.leveldb_create_snapshot(db.Handle);
        }

        ~Snapshot()
        {
            var db = DB.Handle;
            if (db != IntPtr.Zero) {
                Native.leveldb_release_snapshot(db, Handle);
            }
        }
    }
}