LoadState.cs

Siirry tämän tiedoston dokumentaatioon.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.IO;

namespace Jypeli
{
    public class LoadState : IDisposable
    {
        public StorageFile File { get; private set; }

        private FileManager manager;
        private XmlReader reader;
        private List<String> objectsRead;

        internal LoadState( FileManager manager, string fileName )
        {
            this.manager = manager;
            File = manager.Open( fileName, false );
            BeginReadXml();
            objectsRead = new List<string>();
        }

        internal LoadState( StorageFile file, string fileName )
        {
            File = file;
            BeginReadXml();
            objectsRead = new List<string>();
        }

        public void EndLoad()
        {
            reader.Close();
            File.Close();
        }

        public void Dispose()
        {
            reader.Close();
            File.Close();
        }

        private void ResetFile()
        {
            reader.Close();
            reader = null;
            objectsRead.Clear();

            if ( File.Stream.CanSeek )
            {
                File.Stream.Seek( 0, System.IO.SeekOrigin.Begin );
            }
            else
            {
                string fileName = File.Name;
                File.Close();
                File = manager.Open( fileName, false );
            }

            BeginReadXml();
        }

        private void BeginReadXml()
        {
            if ( reader != null )
                return;

            reader = XmlReader.Create( File.Stream );
            reader.Read();
            if ( !reader.IsStartElement( "State" ) ) throw new ArgumentException( "File is corrupted or not a save state file." );
        }

        public T Load<T>( T obj, string name )
        {
            return (T)Load( obj, typeof( T ), name );
        }

        public object Load( object obj, Type type, string name )
        {
            if ( objectsRead.Contains( name ) )
            {
                // Start from beginning
                ResetFile();
            }
            else
                BeginReadXml();

            int depth = 0;

            while ( !reader.EOF )
            {
                reader.Read();

                if ( reader.NodeType == XmlNodeType.None )
                    throw new IOException( "Error loading object: reader not initialized" );

                if ( reader.NodeType == XmlNodeType.Element )
                {
                    if ( depth == 0 )
                    {
                        if ( reader.Name != "Object" )
                            throw new XmlException( "Unexpected element in save state file: " + reader.Name );

                        string objName = reader.GetAttribute( "Name" );
                        if ( string.IsNullOrEmpty( objName ) )
                            throw new XmlException( "Unnamed object in save state file" );

                        if ( name == objName )
                            return File.LoadData( reader, type, obj );
                        else
                            objectsRead.Add( objName );
                    }

                    if ( !reader.IsEmptyElement )
                        depth++;
                }
                else if ( reader.NodeType == XmlNodeType.EndElement )
                {
                    depth--;
                    if ( depth < 0 ) throw new InvalidOperationException( "Error loading object: parse depth < 0" );
                }
            }

            throw new KeyNotFoundException( "Object with name " + name + " could not be found in file " + File.Name );
        }
    }
}