public override (IReadOnlyCollection <Row>, IReadOnlyCollection <Row>, IReadOnlyCollection <Row>) CalculateChanges()
{
List <Row> inserted = new List <Row>();
List <Row> updated = new List <Row>();
List <Row> deleted = new List <Row>();
Db.Config.DatabaseConnectionString.WithReader(Query, reader =>
{
Dictionary <object[], Row> oldState = new Dictionary <object[], Row>(_data, Schema.RowKeyEqualityComparer);
while (reader.Read())
{
var row = Schema.ReadRow(reader);
if (_data.TryGetValue(row.Key, out Row oldRow))
{
oldState.Remove(row.Key);
if (Schema.RowEqualityComparer.Equals(row, oldRow) == false)
{
updated.Add(row);
_data[row.Key] = row;
}
}
else
{
inserted.Add(row);
_data.Add(row.Key, row);
}
}
deleted = oldState.Values.ToList();
_data.RemoveAll(oldState.Keys);
});
return(inserted, updated, deleted);
}
public override IReadOnlyCollection <Row> Initialize()
{
Db.Config.DatabaseConnectionString.WithReader(Query, reader =>
{
Schema = new RowSchema(reader, PrimaryKeyColumns);
_data = new ReducableDictionary <object[], Row>(Schema.RowKeyEqualityComparer);
while (reader.Read())
{
var row = Schema.ReadRow(reader);
_data.Add(row.Key, row);
}
});
return(_data.Values.ToArray());
}
/// <summary>
/// Create a new instance of <see cref="SqlCachedQuery"/>
/// </summary>
/// <param name="db">Database this query belongs to</param>
/// <param name="query">UserQuery that is encapsulated by this query</param>
/// <param name="keyExtractor">Function to extract <typeparamref name="TKey"/> from <typeparamref name="TRow"/></param>
/// <param name="keyComparerFactory">Comparer to compare <typeparamref name="TKey"/></param>
/// <param name="cachingType">Type of cache used to detect changes</param>
/// <param name="primaryKeyColumn">The column used as primary key</param>
/// <param name="additionalPrimaryKeyColumns">Additional column names for the primary key</param>
/// <param name="rowFactory">Function to transform <see cref="Row"/> into <typeparamref name="TRow"/></param>
internal MappedSqlCachedQuery(Database db, string query, Func <Row, TRow> rowFactory, Func <TRow, TKey> keyExtractor, Func <RowSchema, IEqualityComparer <TKey> > keyComparerFactory, CachingType cachingType, string primaryKeyColumn, params string[] additionalPrimaryKeyColumns) : base(Guid.NewGuid())
{
_rowFactory = rowFactory;
_keyExtractor = keyExtractor;
switch (cachingType)
{
case CachingType.InMemory:
_view = new InMemoryCache(db, query, new[] { primaryKeyColumn }.Union(additionalPrimaryKeyColumns).ToArray());
break;
case CachingType.SqlTable:
_view = new SqlTableCache(db, query, new[] { primaryKeyColumn }.Union(additionalPrimaryKeyColumns).ToArray());
break;
case CachingType.SqlInMemoryTable:
_view = new SqlMemoryTableCache(db, query, new[] { primaryKeyColumn }.Union(additionalPrimaryKeyColumns).ToArray());
break;
default:
throw new ArgumentOutOfRangeException(nameof(cachingType), cachingType, null);
}
lock (_dataAccessLock)
{
_view.Invalidated += ViewOnInvalidated;
_disposeHelper.Attach(() => _view.Invalidated -= ViewOnInvalidated);
var data = _view.Initialize();
_rows = new ReducableDictionary <TKey, TRow>(data.Count, keyComparerFactory(_view.Schema));
foreach (var row in data)
{
var entry = rowFactory(row);
var key = keyExtractor(entry);
_rows.Add(key, entry);
}
_disposeHelper.Attach(_view);
}
}
private void ViewOnInvalidated()
{
var changes = _view.CalculateChanges();
lock (_dataAccessLock)
{
foreach (var row in changes.Item1)
{
var entry = _rowFactory(row);
var key = _keyExtractor(entry);
_rows.Add(key, entry);
}
foreach (var row in changes.Item2)
{
var entry = _rowFactory(row);
var key = _keyExtractor(entry);
_rows[key] = entry;
}
_rows.RemoveAll(changes.Item3.Select(_rowFactory).Select(_keyExtractor));
}
}
