From 0ce05fa621ba95ba3ce98f99cb14fec549409069 Mon Sep 17 00:00:00 2001
From: Shritesh Bhattarai <shritesh@shritesh.com>
Date: Tue, 30 Apr 2019 20:06:39 -0500
Subject: [PATCH 1/2] wasi: import clock and timestamp function/types

---
 std/os/wasi/core.zig | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/std/os/wasi/core.zig b/std/os/wasi/core.zig
index b296b83c70..77fd831f81 100644
--- a/std/os/wasi/core.zig
+++ b/std/os/wasi/core.zig
@@ -1,18 +1,28 @@
+pub const clockid_t = u32;
 pub const errno_t = u16;
 pub const exitcode_t = u32;
 pub const fd_t = u32;
 pub const signal_t = u8;
+pub const timestamp_t = u64;
 
 pub const ciovec_t = extern struct {
     buf: [*]const u8,
     buf_len: usize,
 };
 
+pub const CLOCK_REALTIME = 0;
+pub const CLOCK_MONOTONIC = 1;
+pub const CLOCK_PROCESS_CPUTIME_ID = 2;
+pub const CLOCK_THREAD_CPUTIME_ID = 3;
+
 pub const SIGABRT: signal_t = 6;
 
 pub extern "wasi_unstable" fn args_get(argv: [*][*]u8, argv_buf: [*]u8) errno_t;
 pub extern "wasi_unstable" fn args_sizes_get(argc: *usize, argv_buf_size: *usize) errno_t;
 
+pub extern "wasi_unstable" fn clock_res_get(clock_id: clockid_t, resolution: *timestamp_t) errno_t;
+pub extern "wasi_unstable" fn clock_time_get(clock_id: clockid_t, precision: timestamp_t, timestamp: *timestamp_t) errno_t;
+
 pub extern "wasi_unstable" fn environ_get(environ: [*]?[*]u8, environ_buf: [*]u8) errno_t;
 pub extern "wasi_unstable" fn environ_sizes_get(environ_count: *usize, environ_buf_size: *usize) errno_t;
 

From d395ed2d403aa0ff57c493052e3675de23292424 Mon Sep 17 00:00:00 2001
From: Shritesh Bhattarai <shritesh@shritesh.com>
Date: Tue, 30 Apr 2019 20:43:43 -0500
Subject: [PATCH 2/2] wasi: implement timestamp

---
 std/os/time.zig      | 13 +++++++++++++
 std/os/wasi/core.zig |  8 ++++----
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/std/os/time.zig b/std/os/time.zig
index 66ceedb1b6..d742c5d03b 100644
--- a/std/os/time.zig
+++ b/std/os/time.zig
@@ -7,6 +7,7 @@ const testing = std.testing;
 const windows = std.os.windows;
 const linux = std.os.linux;
 const darwin = std.os.darwin;
+const wasi = std.os.wasi;
 const posix = std.os.posix;
 
 pub const epoch = @import("epoch.zig");
@@ -64,9 +65,21 @@ pub const milliTimestamp = switch (builtin.os) {
     Os.windows => milliTimestampWindows,
     Os.linux, Os.freebsd, Os.netbsd => milliTimestampPosix,
     Os.macosx, Os.ios => milliTimestampDarwin,
+    Os.wasi => milliTimestampWasi,
     else => @compileError("Unsupported OS"),
 };
 
+fn milliTimestampWasi() u64 {
+    var ns: wasi.timestamp_t = undefined;
+
+    // TODO: Verify that precision is ignored
+    const err = wasi.clock_time_get(wasi.CLOCK_REALTIME, 1, &ns);
+    debug.assert(err == wasi.ESUCCESS);
+
+    const ns_per_ms = 1000;
+    return @divFloor(ns, ns_per_ms);
+}
+
 fn milliTimestampWindows() u64 {
     //FileTime has a granularity of 100 nanoseconds
     //  and uses the NTFS/Windows epoch
diff --git a/std/os/wasi/core.zig b/std/os/wasi/core.zig
index 77fd831f81..23a0c7ba65 100644
--- a/std/os/wasi/core.zig
+++ b/std/os/wasi/core.zig
@@ -10,10 +10,10 @@ pub const ciovec_t = extern struct {
     buf_len: usize,
 };
 
-pub const CLOCK_REALTIME = 0;
-pub const CLOCK_MONOTONIC = 1;
-pub const CLOCK_PROCESS_CPUTIME_ID = 2;
-pub const CLOCK_THREAD_CPUTIME_ID = 3;
+pub const CLOCK_REALTIME: clockid_t = 0;
+pub const CLOCK_MONOTONIC: clockid_t = 1;
+pub const CLOCK_PROCESS_CPUTIME_ID: clockid_t = 2;
+pub const CLOCK_THREAD_CPUTIME_ID: clockid_t = 3;
 
 pub const SIGABRT: signal_t = 6;