Implement async event streaming

Sources/Inotify/InotifyEventParser.swift

@@ -0,0 +1,57 @@
+import CInotify
+
+struct InotifyEventParser {
+	static let readBufferSize = 4096
+
+	static func parse(fromFileDescriptor fd: Int32) -> [RawInotifyEvent] {
+		let buffer = UnsafeMutableRawPointer.allocate(
+			byteCount: Self.readBufferSize,
+			alignment: MemoryLayout<inotify_event>.alignment
+		)
+		defer { buffer.deallocate() }
+
+		let bytesRead = read(fd, buffer, readBufferSize)
+		guard bytesRead > 0 else { return [] }
+
+		return Self.parseEventBuffer(buffer, bytesRead: bytesRead)
+	}
+
+	private static func parseEventBuffer(
+		_ buffer: UnsafeMutableRawPointer,
+		bytesRead: Int
+	) -> [RawInotifyEvent] {
+		var events: [RawInotifyEvent] = []
+		var offset = 0
+
+		while offset < bytesRead {
+			let eventPointer = buffer.advanced(by: offset)
+			let rawEvent = eventPointer.assumingMemoryBound(to: inotify_event.self).pointee
+
+			events.append(RawInotifyEvent(
+				watchDescriptor: rawEvent.wd,
+				mask: InotifyEventMask(rawValue: rawEvent.mask),
+				cookie: rawEvent.cookie,
+				name: Self.extractName(from: eventPointer, nameLength: rawEvent.len)
+			))
+
+			offset += Self.eventSize(nameLength: rawEvent.len)
+		}
+
+		return events
+	}
+
+	private static func extractName(
+		from eventPointer: UnsafeMutableRawPointer,
+		nameLength: UInt32
+	) -> String {
+		guard nameLength > 0 else { return "" }
+		let namePointer = eventPointer
+			.advanced(by: MemoryLayout<inotify_event>.size)
+			.assumingMemoryBound(to: CChar.self)
+		return String(cString: namePointer)
+	}
+
+	private static func eventSize(nameLength: UInt32) -> Int {
+		MemoryLayout<inotify_event>.size + Int(nameLength)
+	}
+}