std/os: add File.SetReadDeadline, File.SetWriteDeadline

Author: mertcandav

std/internal/poll/fd.jule

@@ -10,6 +10,10 @@ use "std/sys"
 // Throw when a file descriptor is used after it has been closed.
 let mut ErrFileClosing = errors::New("use of closed file")
 
+// Throw when a request is made to set a deadline
+// on a file type that does not use the poller.
+let mut ErrNoDeadline = errors::New("file type does not support deadline")
+
 // FD flags. Kind flags should not be combined like File|Console|Socket.
 const (
 	File         = 1 << iota // Standard file descriptor.

std/os/file.jule

@@ -5,6 +5,7 @@
 use "std/internal/poll"
 use "std/io"
 use "std/sys"
+use "std/time"
 use "std/unsafe"
 
 // The name of the operating system's “null device.”
@@ -213,6 +214,36 @@ impl File {
 		ret self.fd.ShouldAsync()
 	}
 
+	// Sets or updates a deadline for the future read operations.
+	// If the deadline is given as 0, the deadline is cleared.
+	// The deadline is evaluated against an absolute point in time.
+	// In practice, the given deadline is equivalent to `time::Now().Add(deadline)`.
+	// It does not apply per operation, but remains valid until this absolute time.
+	// Any operation initiated after this deadline has passed will fail.
+	//
+	// If file does not supports async I/O, throws error.
+	fn SetReadDeadline(mut *self, deadline: time::Duration)! {
+		if !self.ShouldAsync() {
+			throw poll::ErrNoDeadline
+		}
+		self.fd.SetReadDeadline(deadline)
+	}
+
+	// Sets or updates a deadline for the future write operations.
+	// If the deadline is given as 0, the deadline is cleared.
+	// The deadline is evaluated against an absolute point in time.
+	// In practice, the given deadline is equivalent to `time::Now().Add(deadline)`.
+	// It does not apply per operation, but remains valid until this absolute time.
+	// Any operation initiated after this deadline has passed will fail.
+	//
+	// If file does not supports async I/O, throws error.
+	fn SetWriteDeadline(mut *self, deadline: time::Duration)! {
+		if !self.ShouldAsync() {
+			throw poll::ErrNoDeadline
+		}
+		self.fd.SetWriteDeadline(deadline)
+	}
+
 	// Writes bytes to handle and returns written byte count.
 	// The number of bytes written can never exceed the length of the buf.
 	async fn Write(mut *self, buf: []byte)!: (n: int) {