1 files changed, 66 insertions, 0 deletions
diff --git a/defer_after.go b/defer_after.go
new file mode 100644
index 0000000..ce20f81
--- /dev/null
+++ b/defer_after.go
@@ -0,0 +1,66 @@
+package argvpb
+
+import (
+	"fmt"
+	"time"
+)
+
+// RunIfTakesLonger schedules a function `f` to run after a duration `d`.
+// It returns a "cancel" function. If the cancel function is called before
+// the duration `d` has passed, the scheduled function `f` will not be executed.
+//
+// This is designed to be used with defer, like so:
+//
+//	func myFunc() {
+//		cancel := RunIfTakesLonger(time.Second, func() {
+//			fmt.Println("myFunc took more than a second!")
+//		})
+//		defer cancel()
+//
+//		// ... rest of the function
+//	}
+func RunIfTakesLonger(d time.Duration, f func()) (cancel func()) {
+	// time.AfterFunc executes a function in its own goroutine after the
+	// specified duration. It returns a Timer that can be used to cancel it.
+	timer := time.AfterFunc(d, f)
+
+	// We return a function that stops the timer.
+	// The caller is expected to call this function using `defer`.
+	return func() {
+		// The Stop method returns true if it successfully prevented the
+		// timer from firing. We don't need the return value here, but it's
+		// useful for understanding.
+		timer.Stop()
+	}
+}
+
+// A task that takes less time than the timeout.
+func shortTask() {
+	fmt.Println("--- Running shortTask (will take 500ms) ---")
+	cancel := RunIfTakesLonger(time.Second, func() {
+		fmt.Println("!!! This should NOT be printed !!!")
+	})
+	defer cancel()
+
+	fmt.Println("shortTask: working...")
+	time.Sleep(500 * time.Millisecond)
+	fmt.Println("shortTask: finished.")
+}
+
+// A task that takes more time than the timeout.
+func longTask() {
+	fmt.Println("\n--- Running longTask (will take 2 seconds) ---")
+	cancel := RunIfTakesLonger(time.Second, func() {
+		fmt.Println(">>> longTask took more than 1 second! Clean-up function executed. <<<")
+	})
+	defer cancel()
+
+	fmt.Println("longTask: working...")
+	time.Sleep(2 * time.Second)
+	fmt.Println("longTask: finished.")
+}
+
+func main() {
+	shortTask()
+	longTask()
+}