Add support for timespec, UTIME_NOW, UTIME_OMIT on wasm32-wasi.

src/time/clock.rs

@@ -1,10 +1,10 @@
-use crate::zero_ok;
-use std::mem::MaybeUninit;
+#[cfg(not(target_os = "wasi"))]
+use {crate::zero_ok, std::mem::MaybeUninit};
 
 pub use libc::{timespec, UTIME_NOW, UTIME_OMIT};
 
 /// `clockid_t`
-#[cfg(not(any(target_os = "macos", target_os = "ios")))]
+#[cfg(not(any(target_os = "macos", target_os = "ios", target_os = "wasi")))]
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
 #[repr(i32)]
 pub enum ClockId {
@@ -42,6 +42,7 @@ pub enum ClockId {
 }
 
 /// `clock_getres(id)`
+#[cfg(not(target_os = "wasi"))]
 pub fn clock_getres(id: ClockId) -> timespec {
     let mut timespec = MaybeUninit::<timespec>::uninit();
     zero_ok(unsafe { libc::clock_getres(id as libc::clockid_t, timespec.as_mut_ptr()) }).unwrap();
@@ -49,6 +50,7 @@ pub fn clock_getres(id: ClockId) -> timespec {
 }
 
 /// `clock_gettime(id)`
+#[cfg(not(target_os = "wasi"))]
 pub fn clock_gettime(id: ClockId) -> timespec {
     let mut timespec = MaybeUninit::<timespec>::uninit();
     zero_ok(unsafe { libc::clock_gettime(id as libc::clockid_t, timespec.as_mut_ptr()) }).unwrap();

src/time/mod.rs

@@ -1,8 +1,12 @@
 //! Time-related operations.
 
-#[cfg(not(any(target_os = "wasi", target_os = "redox")))] // not implemented in libc for WASI yet
+#[cfg(not(target_os = "redox"))]
 mod clock;
 
+// TODO: Convert WASI'S clock APIs to use handles rather than ambient
+// clock identifiers, update `wasi-libc`, and then add support in `posish`.
 #[cfg(not(any(target_os = "wasi", target_os = "redox")))]
-// not implemented in libc for WASI yet
-pub use clock::{clock_getres, clock_gettime, timespec, ClockId, UTIME_NOW, UTIME_OMIT};
+pub use clock::{clock_getres, clock_gettime, ClockId};
+
+#[cfg(not(target_os = "redox"))]
+pub use clock::{timespec, UTIME_NOW, UTIME_OMIT};