namespace GMap.NET.CacheProviders{
using System;
using System.Data.SqlClient;
using System.Diagnostics;
using System.IO;
/// <summary>
/// image cache for ms sql server
/// optimized by mmurfinsimmons@gmail.com
/// </summary>
public class MsSQLPureImageCache : PureImageCache, IDisposable
{
string connectionString = string.Empty;
public string ConnectionString
{
get
{
return connectionString;
}
set
{
if(connectionString != value)
{
connectionString = value;
if(Initialized)
{
Dispose();
Initialize();
}
}
}
}
SqlCommand cmdInsert;
SqlCommand cmdFetch;
SqlConnection cnGet;
SqlConnection cnSet;
bool initialized = false;
/// <summary>
/// is cache initialized
/// </summary>
public bool Initialized
{
get
{
lock(this)
{
return initialized;
}
}
private set
{
lock(this)
{
initialized = value;
}
}
}
/// <summary>
/// inits connection to server
/// </summary>
/// <returns></returns>
public bool Initialize()
{
lock(this)
{
if(!Initialized)
{
#region prepare mssql & cache table
try
{
// different connections so the multi-thread inserts and selects don't collide on open readers.
this.cnGet = new SqlConnection(connectionString);
this.cnGet.Open();
this.cnSet = new SqlConnection(connectionString);
this.cnSet.Open();
bool tableexists = false;
using(SqlCommand cmd = new SqlCommand("select object_id('GMapNETcache')", cnGet))
{
object objid = cmd.ExecuteScalar();
tableexists = (objid != null && objid != DBNull.Value);
}
if(!tableexists)
{
using(SqlCommand cmd = new SqlCommand(
"CREATE TABLE [GMapNETcache] ( \n"
+ " [Type] [int] NOT NULL, \n"
+ " [Zoom] [int] NOT NULL, \n"
+ " [X] [int] NOT NULL, \n"
+ " [Y] [int] NOT NULL, \n"
+ " [Tile] [image] NOT NULL, \n"
+ " CONSTRAINT [PK_GMapNETcache] PRIMARY KEY CLUSTERED (Type, Zoom, X, Y) \n"
+ ")", cnGet))
{
cmd.ExecuteNonQuery();
}
}
this.cmdFetch = new SqlCommand("SELECT [Tile] FROM [GMapNETcache] WITH (NOLOCK) WHERE [X]=@x AND [Y]=@y AND [Zoom]=@zoom AND [Type]=@type", cnGet);
this.cmdFetch.Parameters.Add("@x", System.Data.SqlDbType.Int);
this.cmdFetch.Parameters.Add("@y", System.Data.SqlDbType.Int);
this.cmdFetch.Parameters.Add("@zoom", System.Data.SqlDbType.Int);
this.cmdFetch.Parameters.Add("@type", System.Data.SqlDbType.Int);
this.cmdFetch.Prepare();
this.cmdInsert = new SqlCommand("INSERT INTO [GMapNETcache] ( [X], [Y], [Zoom], [Type], [Tile] ) VALUES ( @x, @y, @zoom, @type, @tile )", cnSet);
this.cmdInsert.Parameters.Add("@x", System.Data.SqlDbType.Int);
this.cmdInsert.Parameters.Add("@y", System.Data.SqlDbType.Int);
this.cmdInsert.Parameters.Add("@zoom", System.Data.SqlDbType.Int);
this.cmdInsert.Parameters.Add("@type", System.Data.SqlDbType.Int);
this.cmdInsert.Parameters.Add("@tile", System.Data.SqlDbType.Image); //, calcmaximgsize);
//can't prepare insert because of the IMAGE field having a variable size. Could set it to some 'maximum' size?
Initialized = true;
}
catch(Exception ex)
{
this.initialized = false;
Debug.WriteLine(ex.Message);
}
#endregion
}
return Initialized;
}
}
#region IDisposable Members
public void Dispose()
{
lock(cmdInsert)
{
if(cmdInsert != null)
{
cmdInsert.Dispose();
cmdInsert = null;
}
if(cnSet != null)
{
cnSet.Dispose();
cnSet = null;
}
}
lock(cmdFetch)
{
if(cmdFetch != null)
{
cmdFetch.Dispose();
cmdFetch = null;
}
if(cnGet != null)
{
cnGet.Dispose();
cnGet = null;
}
}
Initialized = false;
}
#endregion
#region PureImageCache Members
public bool PutImageToCache(MemoryStream tile, MapType type, Point pos, int zoom)
{
bool ret = true;
{
if(Initialize())
{
try
{
lock(cmdInsert)
{
cmdInsert.Parameters["@x"].Value = pos.X;
cmdInsert.Parameters["@y"].Value = pos.Y;
cmdInsert.Parameters["@zoom"].Value = zoom;
cmdInsert.Parameters["@type"].Value = (int) type;
cmdInsert.Parameters["@tile"].Value = tile.GetBuffer();
cmdInsert.ExecuteNonQuery();
}
}
catch(Exception ex)
{
Debug.WriteLine(ex.ToString());
ret = false;
Dispose();
}
}
}
return ret;
}
public PureImage GetImageFromCache(MapType type, Point pos, int zoom)
{
PureImage ret = null;
{
if(Initialize())
{
try
{
object odata = null;
lock(cmdFetch)
{
cmdFetch.Parameters["@x"].Value = pos.X;
cmdFetch.Parameters["@y"].Value = pos.Y;
cmdFetch.Parameters["@zoom"].Value = zoom;
cmdFetch.Parameters["@type"].Value = (int) type;
odata = cmdFetch.ExecuteScalar();
}
if(odata != null && odata != DBNull.Value)
{
byte[] tile = (byte[]) odata;
if(tile != null && tile.Length > 0)
{
if(GMaps.Instance.ImageProxy != null)
{
MemoryStream stm = new MemoryStream(tile, 0, tile.Length, false, true);
ret = GMaps.Instance.ImageProxy.FromStream(stm);
if(ret != null)
{
ret.Data = stm;
}
}
}
tile = null;
}
}
catch(Exception ex)
{
Debug.WriteLine(ex.ToString());
ret = null;
Dispose();
}
}
}
return ret;
}
#endregion
}
}
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