/// <summary>
/// Populates a <see cref="ReadOnlyListSubject{T}"/> with the full paths to all of the files that currently exist within
/// the scope of the specified <see cref="FileSystemWatcher"/>, and also responds to changes by adding the full paths of files
/// that are created and removing those that are deleted.
/// </summary>
/// <param name="watcher">The object that specifies the directory to be watched and the files to be included.</param>
/// <returns>A <see cref="ReadOnlyListSubject{T}"/> that responds to changes from the specified <see cref="FileSystemWatcher"/>
/// by adding the full paths of files that are created and removing those that are deleted, and also adds the full paths to all
/// of the files that initially exist within the scope of the specified <see cref="FileSystemWatcher"/>.</returns>
public static ReadOnlyListSubject <string> Collect(this FileSystemWatcher watcher)
{
Contract.Requires(watcher != null);
Contract.Ensures(Contract.Result <ReadOnlyListSubject <string> >() != null);
return(watcher.CollectInternal(false, all => all.SelectMany(n => n.ToModifications()), Scheduler.CurrentThread));
}
/// <summary>
/// Populates a <see cref="ReadOnlyListSubject{T}"/> with elements projected from the full paths to all of the files that currently exist within
/// the scope of the specified <see cref="FileSystemWatcher"/>, and also responds to changes by adding elements projected from the full paths of files
/// that are created and removing those that are deleted.
/// </summary>
/// <typeparam name="TResult">The type of the projected elements in the list.</typeparam>
/// <param name="watcher">The object that specifies the directory to be watched and the files to be included.</param>
/// <param name="selector">Projects a sequence of file change notifications into a sequence from which the list is populated.</param>
/// <returns>A <see cref="ReadOnlyListSubject{T}"/> that responds to changes from the specified <see cref="FileSystemWatcher"/>
/// by adding the full paths of files that are created and removing those that are deleted, and also adds the full paths to all
/// of the files that initially exist within the scope of the specified <see cref="FileSystemWatcher"/>.</returns>
public static ReadOnlyListSubject <TResult> Collect <TResult>(
this FileSystemWatcher watcher,
Func <IObservable <CollectionNotification <string> >, IObservable <CollectionModification <TResult> > > selector)
{
Contract.Requires(watcher != null);
Contract.Requires(selector != null);
Contract.Ensures(Contract.Result <ReadOnlyListSubject <TResult> >() != null);
return(watcher.CollectInternal(false, selector, Scheduler.CurrentThread));
}