From 907008df6695b5ee3d1b54afb8ec6d36ed42b3c2 Mon Sep 17 00:00:00 2001
From: Mathieu Trossevin <mathieu.trossevin@gmail.com>
Date: Sat, 6 Jan 2024 14:45:36 +0100
Subject: [PATCH] notify: Use Duration inside the newtype Microseconds

---
 src/notify/error.rs | 15 +++++++++++++++
 src/notify/mod.rs   | 12 ++++++------
 src/notify/types.rs | 21 ++++++++++++++-------
 3 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/src/notify/error.rs b/src/notify/error.rs
index 41871a2..d64b824 100644
--- a/src/notify/error.rs
+++ b/src/notify/error.rs
@@ -121,3 +121,18 @@ impl Display for OtherStateError {
 }
 
 impl Error for OtherStateError {}
+
+#[derive(Debug)]
+pub enum MicrosecondsFromDurationError {
+    NoMicroseconds,
+}
+
+impl Display for MicrosecondsFromDurationError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::NoMicroseconds => write!(f, "Minimal precision is microseconds but no microseconds are within the Duration provided."),
+        }
+    }
+}
+
+impl Error for MicrosecondsFromDurationError {}
diff --git a/src/notify/mod.rs b/src/notify/mod.rs
index 557ae93..7538dbc 100644
--- a/src/notify/mod.rs
+++ b/src/notify/mod.rs
@@ -230,10 +230,10 @@ pub enum NotifyState<'a> {
     /// Tell the service manager to execute the configured watchdog option.
     WatchdogTrigger,
     /// Reset watchdog timeout value during runtime.
-    /// The value is in microseconds.
+    /// Minimal precision is microseconds, not nanoseconds.
     WatchdogUsec(types::Microseconds),
     /// Tells the service manager to extend the startup, runtime or shutdown service timeout corresponding the current state.
-    /// The value is in microseconds.
+    /// Minimal precision is microseconds, not nanoseconds.
     ExtendTimeoutUsec(types::Microseconds),
 }
 
@@ -254,11 +254,11 @@ impl<'a> Display for NotifyState<'a> {
             NotifyState::Stopping => f.write_str("STOPPING=1"),
             NotifyState::Watchdog => f.write_str("WATCHDOG=1"),
             NotifyState::WatchdogTrigger => f.write_str("WATCHDOG=trigger"),
-            NotifyState::WatchdogUsec(types::Microseconds(milliseconds)) => {
-                write!(f, "WATCHDOG_USEC={milliseconds}")
+            NotifyState::WatchdogUsec(duration) => {
+                write!(f, "WATCHDOG_USEC={duration}")
             }
-            NotifyState::ExtendTimeoutUsec(types::Microseconds(milliseconds)) => {
-                write!(f, "EXTEND_TIMEOUT_USEC={milliseconds}")
+            NotifyState::ExtendTimeoutUsec(duration) => {
+                write!(f, "EXTEND_TIMEOUT_USEC={duration}")
             }
         }
     }
diff --git a/src/notify/types.rs b/src/notify/types.rs
index d260d16..b87dc91 100644
--- a/src/notify/types.rs
+++ b/src/notify/types.rs
@@ -1,5 +1,7 @@
 //! Newtypes used by [`NotifyState`](super::NotifyState)
 
+use core::{fmt::Display, time::Duration};
+
 use super::error;
 
 /// Allowed File descriptor name.
@@ -72,17 +74,22 @@ impl AsRef<str> for StatusLine<'_> {
 
 /// Semantic type representing a number of microseconds.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct Microseconds(pub(super) u64);
+pub struct Microseconds(Duration);
 
-impl From<u64> for Microseconds {
-    fn from(value: u64) -> Self {
-        Self(value)
+impl TryFrom<Duration> for Microseconds {
+    type Error = error::MicrosecondsFromDurationError;
+
+    fn try_from(value: Duration) -> Result<Self, Self::Error> {
+        if value.as_micros() == 0 {
+            return Err(Self::Error::NoMicroseconds);
+        }
+        Ok(Self(value))
     }
 }
 
-impl AsRef<u64> for Microseconds {
-    fn as_ref(&self) -> &u64 {
-        &self.0
+impl Display for Microseconds {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0.as_micros())
     }
 }