Prefactor - Improvements on LSPSDateTime

Introduce new_from_duration_since_epoch constructor from Duration. Also
add abs_diff function to use on client / service. Also do feature='time'
instead of feature='std' on time related functionality

Author: martinsaposnic

lightning-liquidity/src/lsps0/ser.rs

@@ -29,7 +29,8 @@ use lightning::util::ser::{LengthLimitedRead, LengthReadable, WithoutLength};
 
 use bitcoin::secp256k1::PublicKey;
 
-#[cfg(feature = "std")]
+use core::time::Duration;
+#[cfg(feature = "time")]
 use std::time::{SystemTime, UNIX_EPOCH};
 
 use serde::de::{self, MapAccess, Visitor};
@@ -204,7 +205,7 @@ impl LSPSDateTime {
 	}
 
 	/// Returns if the given time is in the past.
-	#[cfg(feature = "std")]
+	#[cfg(feature = "time")]
 	pub fn is_past(&self) -> bool {
 		let now_seconds_since_epoch = SystemTime::now()
 			.duration_since(UNIX_EPOCH)
@@ -214,6 +215,16 @@ impl LSPSDateTime {
 			self.0.timestamp().try_into().expect("expiration to be ahead of unix epoch");
 		now_seconds_since_epoch > datetime_seconds_since_epoch
 	}
+
+	/// Returns the time in seconds since the unix epoch.
+	pub fn abs_diff(&self, other: &Self) -> u64 {
+		self.0.timestamp().abs_diff(other.0.timestamp())
+	}
+
+	/// Returns the time in seconds since the unix epoch.
+	pub fn new_from_duration_since_epoch(duration: Duration) -> Self {
+		Self(chrono::DateTime::UNIX_EPOCH + duration)
+	}
 }
 
 impl FromStr for LSPSDateTime {

lightning-liquidity/src/lsps2/utils.rs

@@ -28,13 +28,13 @@ pub fn is_valid_opening_fee_params(
 }
 
 /// Determines if the given parameters are expired, or still valid.
-#[cfg_attr(not(feature = "std"), allow(unused_variables))]
+#[cfg_attr(not(feature = "time"), allow(unused_variables))]
 pub fn is_expired_opening_fee_params(fee_params: &LSPS2OpeningFeeParams) -> bool {
-	#[cfg(feature = "std")]
+	#[cfg(feature = "time")]
 	{
 		fee_params.valid_until.is_past()
 	}
-	#[cfg(not(feature = "std"))]
+	#[cfg(not(feature = "time"))]
 	{
 		// TODO: We need to find a way to check expiry times in no-std builds.
 		false