From a9f8975ed381a7d5aec41584c840f70a056828cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Silva?=
 <123550+andresilva@users.noreply.github.com>
Date: Fri, 31 May 2024 09:20:29 +0100
Subject: [PATCH] allow reading the timestamp for build date from
 SOURCE_DATE_EPOCH (#95)

---
 Cargo.lock     |  3 +++
 cli/Cargo.toml |  3 +++
 cli/build.rs   | 26 ++++++++++----------------
 3 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 2fbf1ab..49aec8a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -608,7 +608,9 @@ checksum = "a21f936df1771bf62b77f047b726c4625ff2e8aa607c01ec06e5a05bd8463401"
 dependencies = [
  "android-tzdata",
  "iana-time-zone",
+ "js-sys",
  "num-traits",
+ "wasm-bindgen",
  "windows-targets 0.52.5",
 ]
 
@@ -4188,6 +4190,7 @@ name = "subwasm"
 version = "0.21.2"
 dependencies = [
  "assert_cmd",
+ "chrono",
  "clap",
  "color-eyre",
  "env_logger 0.11.3",
diff --git a/cli/Cargo.toml b/cli/Cargo.toml
index 759eb89..daa22ab 100644
--- a/cli/Cargo.toml
+++ b/cli/Cargo.toml
@@ -23,6 +23,9 @@ repository = "https://github.com/chevdor/subwasm"
 name = "subwasm"
 path = "src/main.rs"
 
+[build-dependencies]
+chrono = "0.4"
+
 [dependencies]
 assert_cmd = "2.0"
 clap = { version = "4.0", features = [
diff --git a/cli/build.rs b/cli/build.rs
index aab38ba..5086e54 100644
--- a/cli/build.rs
+++ b/cli/build.rs
@@ -1,3 +1,5 @@
+use chrono::{DateTime, Utc};
+
 use std::{borrow::Cow, process::Command};
 
 fn main() {
@@ -11,23 +13,15 @@ pub fn generate_cargo_keys() {
 }
 
 pub fn generate_cargo_key_build_date() {
-	let build_date = match Command::new("date").args(["-u", "+%FT%TZ"]).output() {
-		Ok(o) if o.status.success() => {
-			let sha = String::from_utf8_lossy(&o.stdout).trim().to_owned();
-			Cow::from(sha)
-		}
-		Ok(o) => {
-			let status = o.status;
-			println!("cargo:warning=Failed fetching the date timestamp: {status}");
-			Cow::from("unknown")
-		}
-		Err(err) => {
-			println!("cargo:warning=Failed fetching the datge: {err}");
-			Cow::from("unknown")
-		}
-	};
+	let build_date = std::env::var("SOURCE_DATE_EPOCH")
+		.ok()
+		.and_then(|ts| ts.parse::<i64>().ok())
+		.and_then(|ts| DateTime::from_timestamp(ts, 0))
+		.unwrap_or_else(|| Utc::now());
+
+	let formatted_build_date = build_date.format("%Y-%m-%dT%H:%M:%SZ").to_string();
 
-	println!("cargo:rustc-env=SUBWASM_CLI_BUILD_DATE={build_date}");
+	println!("cargo:rustc-env=SUBWASM_CLI_BUILD_DATE={formatted_build_date}");
 }
 
 pub fn generate_cargo_key_git() {