/// <summary>
/// Deletes the Lightning key-value pairs identified by the given set of keys, from the specified database.
/// </summary>
/// <param name="database">The database.</param>
/// <param name="keys">The keys that uniquely identify the key-value pairs to be deleted.</param>
/// <returns></returns>
public async Task<int> DeleteAsync(string database, IEnumerable<byte[]> keys)
{
if (_cancellationToken.IsCancellationRequested)
return 0;
var operation = new WriteOperation
{
Type = WriteOperationType.Delete,
Database = database,
KeyValuePairs = keys.Select(k => new LightningKeyValuePair { Key = k }).ToList() ,
TaskCompletionSource = new TaskCompletionSource<int>()
};
if (!_writeOperationsQueue.IsCompleted)
_writeOperationsQueue.Add(operation);
else
operation.TaskCompletionSource.TrySetCanceled();
var result = await operation.TaskCompletionSource.Task.ConfigureAwait(false);
return result;
}
/// <summary>
/// Drops the specified Lightning database.
/// </summary>
/// <param name="database">The Lightning database to drop.</param>
/// <returns></returns>
public async Task<int> DropAsync(string database)
{
if (_cancellationToken.IsCancellationRequested)
return 0;
var operation = new WriteOperation
{
Type = WriteOperationType.DropDatabase,
Database = database,
TaskCompletionSource = new TaskCompletionSource<int>()
};
if (!_writeOperationsQueue.IsCompleted)
_writeOperationsQueue.Add(operation);
else
operation.TaskCompletionSource.TrySetCanceled();
var result = await operation.TaskCompletionSource.Task.ConfigureAwait(false);
var tryCount = 0;
while (tryCount < 3)
{
tryCount += 1;
LightningDatabase db = null;
_openDatabases.TryRemove(database, out db);
await Task.Delay(TimeSpan.FromSeconds(0.5)).ConfigureAwait(false);
if (!_openDatabases.ContainsKey(database))
break; // We are successful
}
if (_openDatabases.ContainsKey(database))
throw new Exception($"Unable to remove the LightningDB database: {database}");
return result;
}
/// <summary>
/// Updates specified Lightning key-value pairs, in the specified database.
/// </summary>
/// <param name="database">The database.</param>
/// <param name="kvItems">The key-value pairs.</param>
/// <returns></returns>
public async Task<int> UpdateAsync(string database, IEnumerable<LightningKeyValuePair> kvItems)
{
if (_cancellationToken.IsCancellationRequested)
return 0;
var operation = new WriteOperation
{
Type = WriteOperationType.Update,
Database = database,
KeyValuePairs = kvItems,
TaskCompletionSource = new TaskCompletionSource<int>()
};
if (!_writeOperationsQueue.IsCompleted)
_writeOperationsQueue.Add(operation);
else
operation.TaskCompletionSource.TrySetCanceled();
var result = await operation.TaskCompletionSource.Task.ConfigureAwait(false);
return result;
}