/// <summary>
/// Removes outdated tiles from cache.
/// </summary>
private static void RemoveOutdatatedTiles(string filename, TilesMaxAge maxAge)
{
string date = GetSqliteStartDate(maxAge);
if (string.IsNullOrWhiteSpace(date))
{
return;
}
try
{
using (var conn = new SQLiteConnection(string.Format(@"Data Source={0}", filename)))
{
conn.Open();
using (var command = conn.CreateCommand())
{
command.CommandText = string.Format("DELETE FROM Tiles WHERE CacheTime < '{0}'", date);
command.ExecuteNonQuery();
}
}
}
catch (Exception ex)
{
Logger.Current.Warn("Failed to remove outdated tiles from cache.", ex);
}
}
private static DateTime GetStartDate(TilesMaxAge maxAge)
{
var span = default(TimeSpan);
switch (maxAge)
{
case TilesMaxAge.Month:
span = new TimeSpan(-30, 0, 0, 0);
break;
case TilesMaxAge.Month3:
span = new TimeSpan(-90, 0, 0, 0);
break;
case TilesMaxAge.Month6:
span = new TimeSpan(-180, 0, 0, 0);
break;
case TilesMaxAge.Year:
span = new TimeSpan(-365, 0, 0, 0);
break;
}
if (span == default(TimeSpan))
{
return(default(DateTime));
}
return(DateTime.Now.Date.Add(span));
}
private static string GetSqliteStartDate(TilesMaxAge maxAge)
{
if (maxAge == TilesMaxAge.Never)
{
return(string.Empty);
}
var date = GetStartDate(maxAge);
if (date == default(DateTime))
{
return(string.Empty);
}
return(DateTimeSqLite(date));
}
/// <summary>
/// Removes outdated tiles and vaccums database.
/// </summary>
public static void InitDatabase(string filename, TilesMaxAge maxAge)
{
Logger.Current.Trace("In TileCacheHelper.InitDatabase()");
if (_initialized)
{
return;
}
if (File.Exists(filename))
{
if (DebugHelper.CleanTileCache)
{
RemoveOutdatatedTiles(filename, maxAge);
Vacuum(filename);
}
_initialized = true;
}
}
