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@mattlawer
Created September 18, 2016 17:28
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DirectoryMonitor - Swift 3
/*
Copyright (C) 2016 Apple Inc. All Rights Reserved.
See LICENSE.txt for this sample’s licensing information
Abstract:
`DirectoryMonitor` is used to monitor the contents of the provided directory by using a GCD dispatch source.
*/
import Foundation
/// A protocol that allows delegates of `DirectoryMonitor` to respond to changes in a directory.
protocol DirectoryMonitorDelegate: class {
func directoryMonitorDidObserveChange(_ directoryMonitor: DirectoryMonitor)
}
class DirectoryMonitor {
// MARK: Properties
/// The `DirectoryMonitor`'s delegate who is responsible for responding to `DirectoryMonitor` updates.
weak var delegate: DirectoryMonitorDelegate?
/// A file descriptor for the monitored directory.
var monitoredDirectoryFileDescriptor: CInt = -1
/// A dispatch queue used for sending file changes in the directory.
let directoryMonitorQueue = DispatchQueue(label: "com.example.apple-samplecode.lister.directorymonitor", attributes: .concurrent)
/// A dispatch source to monitor a file descriptor created from the directory.
var directoryMonitorSource: DispatchSourceFileSystemObject?
/// URL for the directory being monitored.
var url: URL
// MARK: Initializers
init(URL: URL) {
self.url = URL
}
// MARK: Monitoring
func startMonitoring() {
// Listen for changes to the directory (if we are not already).
if directoryMonitorSource == nil && monitoredDirectoryFileDescriptor == -1 {
// Open the directory referenced by URL for monitoring only.
monitoredDirectoryFileDescriptor = open(url.path, O_EVTONLY)
// Define a dispatch source monitoring the directory for additions, deletions, and renamings.
directoryMonitorSource = DispatchSource.makeFileSystemObjectSource(fileDescriptor: monitoredDirectoryFileDescriptor, eventMask: [.write, .delete], queue: directoryMonitorQueue)
// Define the block to call when a file change is detected.
directoryMonitorSource?.setEventHandler(handler: {
// Call out to the `DirectoryMonitorDelegate` so that it can react appropriately to the change.
self.delegate?.directoryMonitorDidObserveChange(self)
})
// Define a cancel handler to ensure the directory is closed when the source is cancelled.
directoryMonitorSource?.setCancelHandler(handler: {
close(self.monitoredDirectoryFileDescriptor)
self.monitoredDirectoryFileDescriptor = -1
self.directoryMonitorSource = nil
})
// Start monitoring the directory via the source.
directoryMonitorSource?.resume()
}
}
func stopMonitoring() {
// Stop listening for changes to the directory, if the source has been created.
if directoryMonitorSource != nil {
// Stop monitoring the directory via the source.
directoryMonitorSource?.cancel()
}
}
}
@matiasdim
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Hi @mattlawer!
Does not work when a file on the path is updated? I trying to figure out how this works and it fires a notification when I create or remove a file but not when I update the file. Btw I tried changing "[.write, .delete]"to ".all" and it did not worked.

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