From 84d07eaa1f9ad5a010a13064e6a9b7fb2a8f5eab Mon Sep 17 00:00:00 2001
From: daxpedda <daxpedda@gmail.com>
Date: Sun, 24 Dec 2023 20:17:53 +0100
Subject: [PATCH] Add `SystemTimeExt`

---
 .config/topic.dic                |  3 +-
 CHANGELOG.md                     |  4 +++
 src/lib.rs                       | 12 ++++++--
 src/{web => time}/instant.rs     |  0
 src/{web => time}/js.rs          |  0
 src/{web => time}/mod.rs         |  0
 src/{web => time}/system_time.rs |  2 +-
 src/web.rs                       | 49 ++++++++++++++++++++++++++++++++
 8 files changed, 66 insertions(+), 4 deletions(-)
 rename src/{web => time}/instant.rs (100%)
 rename src/{web => time}/js.rs (100%)
 rename src/{web => time}/mod.rs (100%)
 rename src/{web => time}/system_time.rs (98%)
 create mode 100644 src/web.rs

diff --git a/.config/topic.dic b/.config/topic.dic
index b35ca0c..4a27829 100644
--- a/.config/topic.dic
+++ b/.config/topic.dic
@@ -1,7 +1,8 @@
-16
+17
 1G
 1M
 1ns
+APIs
 Atomics
 Changelog
 CHANGELOG
diff --git a/CHANGELOG.md b/CHANGELOG.md
index dc15e56..1c060e5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- Added `web` module containing a platform-specific extension trait to
+  `SystemTime`, allowing conversion from and to `std::time::SystemTime`.
+
 ### Changed
 - Improve performance of `SystemTime` by using `Duration` internally.
 
diff --git a/src/lib.rs b/src/lib.rs
index 66ee784..dd3bf62 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -111,7 +111,15 @@
 	target_family = "wasm",
 	not(any(target_os = "emscripten", target_os = "wasi"))
 ))]
-mod web;
+mod time;
+#[cfg(any(
+	all(
+		target_family = "wasm",
+		not(any(target_os = "emscripten", target_os = "wasi"))
+	),
+	docsrs
+))]
+pub mod web;
 
 #[cfg(not(all(
 	target_family = "wasm",
@@ -123,4 +131,4 @@ pub use std::time::*;
 	target_family = "wasm",
 	not(any(target_os = "emscripten", target_os = "wasi"))
 ))]
-pub use self::web::*;
+pub use self::time::*;
diff --git a/src/web/instant.rs b/src/time/instant.rs
similarity index 100%
rename from src/web/instant.rs
rename to src/time/instant.rs
diff --git a/src/web/js.rs b/src/time/js.rs
similarity index 100%
rename from src/web/js.rs
rename to src/time/js.rs
diff --git a/src/web/mod.rs b/src/time/mod.rs
similarity index 100%
rename from src/web/mod.rs
rename to src/time/mod.rs
diff --git a/src/web/system_time.rs b/src/time/system_time.rs
similarity index 98%
rename from src/web/system_time.rs
rename to src/time/system_time.rs
index cee0760..dfc7d11 100644
--- a/src/web/system_time.rs
+++ b/src/time/system_time.rs
@@ -7,7 +7,7 @@ use std::time::Duration;
 
 /// See [`std::time::SystemTime`].
 #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
-pub struct SystemTime(Duration);
+pub struct SystemTime(pub(crate) Duration);
 
 impl SystemTime {
 	/// See [`std::time::SystemTime::UNIX_EPOCH`].
diff --git a/src/web.rs b/src/web.rs
new file mode 100644
index 0000000..cf9b66e
--- /dev/null
+++ b/src/web.rs
@@ -0,0 +1,49 @@
+//! Platform-specific extensions to `web-time` for the Web platform.
+
+#![allow(clippy::absolute_paths)]
+
+use std::time::SystemTime as StdSystemTime;
+
+use crate::SystemTime;
+
+/// Web-specific extension to [`web_time::SystemTime`](crate::SystemTime).
+pub trait SystemTimeExt {
+	/// Convert [`web_time::SystemTime`](crate::SystemTime) to
+	/// [`std::time::SystemTime`].
+	///
+	/// # Note
+	///
+	/// This might give a misleading impression of compatibility!
+	///
+	/// Considering this functionality will probably be used to interact with
+	/// incompatible APIs of other dependencies, care should be taken that the
+	/// dependency in question doesn't call [`std::time::SystemTime::now()`]
+	/// internally, which would panic.
+	fn to_std(self) -> std::time::SystemTime;
+
+	/// Convert [`std::time::SystemTime`] to
+	/// [`web_time::SystemTime`](crate::SystemTime).
+	///
+	/// # Note
+	///
+	/// This might give a misleading impression of compatibility!
+	///
+	/// Considering this functionality will probably be used to interact with
+	/// incompatible APIs of other dependencies, care should be taken that the
+	/// dependency in question doesn't call [`std::time::SystemTime::now()`]
+	/// internally, which would panic.
+	fn from_std(time: std::time::SystemTime) -> SystemTime;
+}
+
+impl SystemTimeExt for SystemTime {
+	fn to_std(self) -> std::time::SystemTime {
+		StdSystemTime::UNIX_EPOCH + self.0
+	}
+
+	fn from_std(time: std::time::SystemTime) -> SystemTime {
+		Self::UNIX_EPOCH
+			+ time
+				.duration_since(StdSystemTime::UNIX_EPOCH)
+				.expect("found `SystemTime` earlier then unix epoch")
+	}
+}