/// <summary>
/// Creates an observable sequence of bytes by asynchronously reading to the end of the specified <paramref name="stream"/>
/// each time the underlying file is updated and advances the position within the stream to the end.
/// </summary>
/// <param name="stream">The object from which bytes are read as data becomes available.</param>
/// <remarks>
/// <para>
/// The generated sequence is intended to match the specified stream; however, this behavior
/// depends on whether the stream is well-behaved and whether the stream is not being shared. Reading always starts from the
/// current position of the stream. The stream is expected to increment its position
/// when it's read. Each time that the underlying file is updated on disc, reading is expected to begin at the previous position
/// in the stream, but if the stream is shared or it's not well-behaved, then the generated sequence may contain unexpected data.
/// </para>
/// <para>
/// Furthermore, specific changes to the file are not detected. Only the date/time of the last write is monitored for changes.
/// All changes to the date/time of the last write to the file are assumed to indicate that new data has been appended to the
/// end of the file. If data is overwritten in the file after it has already been read from the specified stream, then the last
/// write date/time will be updated causing the stream to be read again, although it will already be at the end of the file so
/// nothing will happen. It is the responsibility of consumers to prevent the file from being deleted, truncated or mutated in
/// any other way that may cause I/O errors or may cause the generated sequence to contain unexpected data.
/// </para>
/// </remarks>
/// <returns>An observable sequence of byte arrays of a default maximum size read from the specified <paramref name="stream"/>.</returns>
public static IObservable <byte[]> ToObservable(this FileStream stream)
{
Contract.Requires(stream != null);
Contract.Requires(stream.CanRead);
Contract.Ensures(Contract.Result <IObservable <byte[]> >() != null);
return(stream.ToObservable(StreamExtensions.defaultBufferSize));
}
/// <summary>
/// Creates an observable sequence by reading to the end of the specified <paramref name="stream"/>
/// each time the underlying file is updated and advances the position within the stream to the end.
/// </summary>
/// <param name="stream">The object from which text is read as it becomes available.</param>
/// <param name="encoding">The character encoding to use.</param>
/// <remarks>
/// <para>
/// The generated sequence is intended to match the specified stream; however, this behavior
/// depends on whether the stream is well-behaved and whether the stream is not being shared. Reading always starts from the
/// current position of the stream. The stream is expected to increment its position
/// when it's read. Each time that the underlying file is updated on disc, reading is expected to begin at the previous position
/// in the stream, but if the stream is shared or it's not well-behaved, then the generated sequence may contain unexpected data.
/// </para>
/// <para>
/// Furthermore, specific changes to the file are not detected. Only the date/time of the last write is monitored for changes.
/// All changes to the date/time of the last write to the file are assumed to indicate that new data has been appended to the
/// end of the file. If data is overwritten in the file after it has already been read from the specified stream, then the last
/// write date/time will be updated causing the stream to be read again, although it will already be at the end of the file so
/// nothing will happen. It is the responsibility of consumers to prevent the file from being deleted, truncated or mutated in
/// any other way that may cause I/O errors or may cause the generated sequence to contain unexpected data.
/// </para>
/// </remarks>
/// <returns>An observable sequence of strings read from the specified <paramref name="stream"/>.</returns>
public static IObservable <string> ToObservable(this FileStream stream, Encoding encoding)
{
Contract.Requires(stream != null);
Contract.Requires(stream.CanRead);
Contract.Requires(encoding != null);
Contract.Ensures(Contract.Result <IObservable <string> >() != null);
return(stream.ToObservable(encoding, TaskPoolScheduler.Default));
}
public static IObservable <byte[]> ToObservable(this FileStream stream, int bufferSize)
{
Contract.Requires(stream != null);
Contract.Requires(stream.CanRead);
Contract.Requires(bufferSize > 0);
Contract.Ensures(Contract.Result <IObservable <byte[]> >() != null);
return(Observable.Using(
() => new FileSystemWatcher(Path.GetDirectoryName(stream.Name), Path.GetFileName(stream.Name))
{
NotifyFilter = NotifyFilters.LastWrite
},
watcher => stream.ToObservable(
bufferSize,
watcher.Watch(WatcherChangeTypes.Created | WatcherChangeTypes.Changed)
.StartWith((FileSystemNotification)null))));
}
