openpgp: Implement date formatting for WASM using chrono crate

1 files changed, 40 insertions, 31 deletions

diff --git a/openpgp/src/fmt.rs b/openpgp/src/fmt.rs
index f7bb8e31..d36217d2 100644
--- a/openpgp/src/fmt.rs
+++ b/openpgp/src/fmt.rs
@@ -269,40 +269,49 @@ pub(crate) fn from_hex(hex: &str, pretty: bool) -> Result<Vec<u8>> {
 /// is not representable using unsigned UNIX time, we return the debug
 /// formatting.
 pub(crate) fn time(t: &std::time::SystemTime) -> String {
-    extern "C" {
-        fn strftime(
-            s: *mut libc::c_char,
-            max: libc::size_t,
-            format: *const libc::c_char,
-            tm: *const libc::tm,
-        ) -> usize;
+    // Actually use a chrono dependency for WASM since there's no strftime
+    // (except for WASI).
+    #[cfg(all(target_arch = "wasm32", target_os = "unknown"))] {
+        chrono::DateTime::<chrono::Utc>::from(t.clone())
+            .format("%Y-%m-%dT%H:%M:%SZ")
+            .to_string()
     }
+    #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))] {
+        extern "C" {
+            fn strftime(
+                s: *mut libc::c_char,
+                max: libc::size_t,
+                format: *const libc::c_char,
+                tm: *const libc::tm,
+            ) -> usize;
+        }
 
-    let t = match t.duration_since(std::time::UNIX_EPOCH) {
-        Ok(t) => t.as_secs() as libc::time_t,
-        Err(_) => return format!("{:?}", t),
-    };
-    let fmt = b"%Y-%m-%dT%H:%M:%SZ\x00";
-    assert_eq!(b"2020-03-26T10:08:10Z\x00".len(), 21);
-    let mut s = [0u8; 21];
-
-    unsafe {
-        let mut tm: libc::tm = std::mem::zeroed();
-
-        #[cfg(unix)]
-        libc::gmtime_r(&t, &mut tm);
-        #[cfg(windows)]
-        libc::gmtime_s(&mut tm, &t);
-
-        strftime(s.as_mut_ptr() as *mut libc::c_char,
-                 s.len(),
-                 fmt.as_ptr() as *const libc::c_char,
-                 &tm);
-    }
+        let t = match t.duration_since(std::time::UNIX_EPOCH) {
+            Ok(t) => t.as_secs() as libc::time_t,
+            Err(_) => return format!("{:?}", t),
+        };
+        let fmt = b"%Y-%m-%dT%H:%M:%SZ\x00";
+        assert_eq!(b"2020-03-26T10:08:10Z\x00".len(), 21);
+        let mut s = [0u8; 21];
+
+        unsafe {
+            let mut tm: libc::tm = std::mem::zeroed();
+
+            #[cfg(unix)]
+            libc::gmtime_r(&t, &mut tm);
+            #[cfg(windows)]
+            libc::gmtime_s(&mut tm, &t);
+
+            strftime(s.as_mut_ptr() as *mut libc::c_char,
+                     s.len(),
+                     fmt.as_ptr() as *const libc::c_char,
+                     &tm);
+        }
 
-    std::ffi::CStr::from_bytes_with_nul(&s)
-        .expect("strftime nul terminates string")
-        .to_string_lossy().into()
+        std::ffi::CStr::from_bytes_with_nul(&s)
+            .expect("strftime nul terminates string")
+            .to_string_lossy().into()
+    }
 }
 
 #[cfg(test)]