1 files changed, 107 insertions, 0 deletions
diff --git a/src/runtime/lock_wasip1.go b/src/runtime/lock_wasip1.go
new file mode 100644
index 0000000..c4fc59f
--- /dev/null
+++ b/src/runtime/lock_wasip1.go
@@ -0,0 +1,107 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build wasip1
+
+package runtime
+
+// wasm has no support for threads yet. There is no preemption.
+// See proposal: https://github.com/WebAssembly/threads
+// Waiting for a mutex or timeout is implemented as a busy loop
+// while allowing other goroutines to run.
+
+const (
+	mutex_unlocked = 0
+	mutex_locked   = 1
+
+	active_spin     = 4
+	active_spin_cnt = 30
+)
+
+func lock(l *mutex) {
+	lockWithRank(l, getLockRank(l))
+}
+
+func lock2(l *mutex) {
+	if l.key == mutex_locked {
+		// wasm is single-threaded so we should never
+		// observe this.
+		throw("self deadlock")
+	}
+	gp := getg()
+	if gp.m.locks < 0 {
+		throw("lock count")
+	}
+	gp.m.locks++
+	l.key = mutex_locked
+}
+
+func unlock(l *mutex) {
+	unlockWithRank(l)
+}
+
+func unlock2(l *mutex) {
+	if l.key == mutex_unlocked {
+		throw("unlock of unlocked lock")
+	}
+	gp := getg()
+	gp.m.locks--
+	if gp.m.locks < 0 {
+		throw("lock count")
+	}
+	l.key = mutex_unlocked
+}
+
+// One-time notifications.
+func noteclear(n *note) {
+	n.key = 0
+}
+
+func notewakeup(n *note) {
+	if n.key != 0 {
+		print("notewakeup - double wakeup (", n.key, ")\n")
+		throw("notewakeup - double wakeup")
+	}
+	n.key = 1
+}
+
+func notesleep(n *note) {
+	throw("notesleep not supported by wasi")
+}
+
+func notetsleep(n *note, ns int64) bool {
+	throw("notetsleep not supported by wasi")
+	return false
+}
+
+// same as runtime·notetsleep, but called on user g (not g0)
+func notetsleepg(n *note, ns int64) bool {
+	gp := getg()
+	if gp == gp.m.g0 {
+		throw("notetsleepg on g0")
+	}
+
+	deadline := nanotime() + ns
+	for {
+		if n.key != 0 {
+			return true
+		}
+		if sched_yield() != 0 {
+			throw("sched_yield failed")
+		}
+		Gosched()
+		if ns >= 0 && nanotime() >= deadline {
+			return false
+		}
+	}
+}
+
+func beforeIdle(int64, int64) (*g, bool) {
+	return nil, false
+}
+
+func checkTimeouts() {}
+
+//go:wasmimport wasi_snapshot_preview1 sched_yield
+func sched_yield() errno