public BlobSizesConnection(BlobSizes blobSizes, string connectionString)
{
this.BlobSizesDatabase = blobSizes;
this.connectionString = connectionString;
this.shaBuffer = new byte[20];
try
{
this.connection = new SqliteConnection(this.connectionString);
this.connection.Open();
using (SqliteCommand pragmaReadUncommittedCommand = this.connection.CreateCommand())
{
// A database connection in read-uncommitted mode does not attempt to obtain read-locks
// before reading from database tables as described above. This can lead to inconsistent
// query results if another database connection modifies a table while it is being read,
// but it also means that a read-transaction opened by a connection in read-uncommitted
// mode can neither block nor be blocked by any other connection
// http://www.sqlite.org/pragma.html#pragma_read_uncommitted
pragmaReadUncommittedCommand.CommandText = $"PRAGMA read_uncommitted=1;";
pragmaReadUncommittedCommand.ExecuteNonQuery();
}
this.querySizeCommand = this.connection.CreateCommand();
this.shaParam = this.querySizeCommand.CreateParameter();
this.shaParam.ParameterName = "@sha";
this.querySizeCommand.CommandText = "SELECT size FROM BlobSizes WHERE sha = (@sha);";
this.querySizeCommand.Parameters.Add(this.shaParam);
this.querySizeCommand.Prepare();
}
catch (Exception e)
{
if (this.querySizeCommand != null)
{
this.querySizeCommand.Dispose();
this.querySizeCommand = null;
}
if (this.connection != null)
{
this.connection.Dispose();
this.connection = null;
}
throw new BlobSizesException(e);
}
}
public BlobSizesConnection(BlobSizes blobSizes)
{
// For unit testing
this.BlobSizesDatabase = blobSizes;
}