/// <summary>Immediately executes a sequence query and return a list of all the results once it has completed.</summary>
public static Task <List <T> > ToListAsync <T>(this IFdbAsyncSequenceQueryable <T> query, CancellationToken ct = default(CancellationToken))
{
if (query == null)
{
throw new ArgumentNullException("query");
}
if (ct.IsCancellationRequested)
{
return(TaskHelpers.FromCancellation <List <T> >(ct));
}
return(query.Provider.ExecuteAsync <List <T> >(query.Expression, ct));
}
/// <summary>Immediately executes a sequence query and return an array of all the results once it has completed.</summary>
public static Task <T[]> ToArrayAsync <T>(this IFdbAsyncSequenceQueryable <T> query, CancellationToken ct = default(CancellationToken))
{
if (query == null)
{
throw new ArgumentNullException(nameof(query));
}
if (ct.IsCancellationRequested)
{
return(Task.FromCanceled <T[]>(ct));
}
return(query.Provider.ExecuteAsync <T[]>(query.Expression, ct));
}
/// <summary>Returns the first element of a sequence query</summary>
public static Task <int> CountAsync <T>(this IFdbAsyncSequenceQueryable <T> query, CancellationToken ct = default(CancellationToken))
{
if (query == null)
{
throw new ArgumentNullException(nameof(query));
}
var expr = FdbQueryExpressions.Single <T, int>(
(FdbQuerySequenceExpression <T>)query.Expression,
"CountAsync",
(source, _ct) => source.CountAsync(_ct)
);
return(query.Provider.CreateQuery <int>(expr).ExecuteSingle(ct));
}
/// <summary>Returns an async sequence that would return the results of this query as they arrive.</summary>
public static IAsyncEnumerable <T> ToAsyncEnumerable <T>(this IFdbAsyncSequenceQueryable <T> query)
{
if (query == null)
{
throw new ArgumentNullException(nameof(query));
}
var sequenceQuery = query as FdbAsyncSequenceQuery <T>;
if (sequenceQuery == null)
{
throw new ArgumentException("Source query type not supported", nameof(query));
}
return(sequenceQuery.ToEnumerable());
}
/// <summary>Returns the first element of a sequence query</summary>
public static Task <T> FirstOrDefaultAsync <T>(this IFdbAsyncSequenceQueryable <T> query, CancellationToken ct = default(CancellationToken))
{
if (query == null)
{
throw new ArgumentNullException(nameof(query));
}
if (ct.IsCancellationRequested)
{
return(Task.FromCanceled <T>(ct));
}
var expr = FdbQueryExpressions.Single <T, T>(
(FdbQuerySequenceExpression <T>)query.Expression,
"FirstOrDefaultAsync",
(source, _ct) => source.FirstOrDefaultAsync(_ct)
);
return(query.Provider.CreateQuery <T>(expr).ExecuteSingle(ct));
}
/// <summary>Filters a sequence query of values based on a predicate.</summary>
public static IFdbAsyncSequenceQueryable <T> Where <T>(this IFdbAsyncSequenceQueryable <T> query, Expression <Func <T, bool> > predicate)
{
if (query == null)
{
throw new ArgumentNullException(nameof(query));
}
if (predicate == null)
{
throw new ArgumentNullException(nameof(predicate));
}
var sourceExpr = query.Expression as FdbQuerySequenceExpression <T>;
if (sourceExpr == null)
{
throw new ArgumentException("query");
}
var expr = FdbQueryExpressions.Filter(sourceExpr, predicate);
return(query.Provider.CreateSequenceQuery <T>(expr));
}
/// <summary>Projects each element of a sequence query into a new form.</summary>
public static IFdbAsyncSequenceQueryable <R> Select <T, R>(this IFdbAsyncSequenceQueryable <T> query, Expression <Func <T, R> > selector)
{
if (query == null)
{
throw new ArgumentNullException(nameof(query));
}
if (selector == null)
{
throw new ArgumentNullException(nameof(selector));
}
var sourceExpr = query.Expression as FdbQuerySequenceExpression <T>;
if (sourceExpr == null)
{
throw new ArgumentException("query");
}
var expr = FdbQueryExpressions.Transform(sourceExpr, selector);
return(query.Provider.CreateSequenceQuery <R>(expr));
}
internal static Task <T> ExecuteSequence <T>(this IFdbAsyncSequenceQueryable <T> query, CancellationToken ct = default(CancellationToken))
{
return(query.Provider.ExecuteAsync <T>(query.Expression, ct));
}
