1 files changed, 186 insertions, 0 deletions
diff --git a/src/pkg/net/fd_mutex_test.go b/src/pkg/net/fd_mutex_test.go
new file mode 100644
index 000000000..8383084b7
--- /dev/null
+++ b/src/pkg/net/fd_mutex_test.go
@@ -0,0 +1,186 @@
+// Copyright 2013 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.
+
+package net
+
+import (
+	"math/rand"
+	"runtime"
+	"testing"
+	"time"
+)
+
+func TestMutexLock(t *testing.T) {
+	var mu fdMutex
+
+	if !mu.Incref() {
+		t.Fatal("broken")
+	}
+	if mu.Decref() {
+		t.Fatal("broken")
+	}
+
+	if !mu.RWLock(true) {
+		t.Fatal("broken")
+	}
+	if mu.RWUnlock(true) {
+		t.Fatal("broken")
+	}
+
+	if !mu.RWLock(false) {
+		t.Fatal("broken")
+	}
+	if mu.RWUnlock(false) {
+		t.Fatal("broken")
+	}
+}
+
+func TestMutexClose(t *testing.T) {
+	var mu fdMutex
+	if !mu.IncrefAndClose() {
+		t.Fatal("broken")
+	}
+
+	if mu.Incref() {
+		t.Fatal("broken")
+	}
+	if mu.RWLock(true) {
+		t.Fatal("broken")
+	}
+	if mu.RWLock(false) {
+		t.Fatal("broken")
+	}
+	if mu.IncrefAndClose() {
+		t.Fatal("broken")
+	}
+}
+
+func TestMutexCloseUnblock(t *testing.T) {
+	c := make(chan bool)
+	var mu fdMutex
+	mu.RWLock(true)
+	for i := 0; i < 4; i++ {
+		go func() {
+			if mu.RWLock(true) {
+				t.Fatal("broken")
+			}
+			c <- true
+		}()
+	}
+	// Concurrent goroutines must not be able to read lock the mutex.
+	time.Sleep(time.Millisecond)
+	select {
+	case <-c:
+		t.Fatal("broken")
+	default:
+	}
+	mu.IncrefAndClose() // Must unblock the readers.
+	for i := 0; i < 4; i++ {
+		select {
+		case <-c:
+		case <-time.After(10 * time.Second):
+			t.Fatal("broken")
+		}
+	}
+	if mu.Decref() {
+		t.Fatal("broken")
+	}
+	if !mu.RWUnlock(true) {
+		t.Fatal("broken")
+	}
+}
+
+func TestMutexPanic(t *testing.T) {
+	ensurePanics := func(f func()) {
+		defer func() {
+			if recover() == nil {
+				t.Fatal("does not panic")
+			}
+		}()
+		f()
+	}
+
+	var mu fdMutex
+	ensurePanics(func() { mu.Decref() })
+	ensurePanics(func() { mu.RWUnlock(true) })
+	ensurePanics(func() { mu.RWUnlock(false) })
+
+	ensurePanics(func() { mu.Incref(); mu.Decref(); mu.Decref() })
+	ensurePanics(func() { mu.RWLock(true); mu.RWUnlock(true); mu.RWUnlock(true) })
+	ensurePanics(func() { mu.RWLock(false); mu.RWUnlock(false); mu.RWUnlock(false) })
+
+	// ensure that it's still not broken
+	mu.Incref()
+	mu.Decref()
+	mu.RWLock(true)
+	mu.RWUnlock(true)
+	mu.RWLock(false)
+	mu.RWUnlock(false)
+}
+
+func TestMutexStress(t *testing.T) {
+	P := 8
+	N := int(1e6)
+	if testing.Short() {
+		P = 4
+		N = 1e4
+	}
+	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(P))
+	done := make(chan bool)
+	var mu fdMutex
+	var readState [2]uint64
+	var writeState [2]uint64
+	for p := 0; p < P; p++ {
+		go func() {
+			r := rand.New(rand.NewSource(rand.Int63()))
+			for i := 0; i < N; i++ {
+				switch r.Intn(3) {
+				case 0:
+					if !mu.Incref() {
+						t.Fatal("broken")
+					}
+					if mu.Decref() {
+						t.Fatal("broken")
+					}
+				case 1:
+					if !mu.RWLock(true) {
+						t.Fatal("broken")
+					}
+					// Ensure that it provides mutual exclusion for readers.
+					if readState[0] != readState[1] {
+						t.Fatal("broken")
+					}
+					readState[0]++
+					readState[1]++
+					if mu.RWUnlock(true) {
+						t.Fatal("broken")
+					}
+				case 2:
+					if !mu.RWLock(false) {
+						t.Fatal("broken")
+					}
+					// Ensure that it provides mutual exclusion for writers.
+					if writeState[0] != writeState[1] {
+						t.Fatal("broken")
+					}
+					writeState[0]++
+					writeState[1]++
+					if mu.RWUnlock(false) {
+						t.Fatal("broken")
+					}
+				}
+			}
+			done <- true
+		}()
+	}
+	for p := 0; p < P; p++ {
+		<-done
+	}
+	if !mu.IncrefAndClose() {
+		t.Fatal("broken")
+	}
+	if !mu.Decref() {
+		t.Fatal("broken")
+	}
+}