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// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package refs
import (
"reflect"
"testing"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/sync"
)
type testCounter struct {
AtomicRefCount
// mu protects the boolean below.
mu sync.Mutex
// destroyed indicates whether this was destroyed.
destroyed bool
}
func (t *testCounter) DecRef(ctx context.Context) {
t.AtomicRefCount.DecRefWithDestructor(ctx, t.destroy)
}
func (t *testCounter) destroy(context.Context) {
t.mu.Lock()
defer t.mu.Unlock()
t.destroyed = true
}
func (t *testCounter) IsDestroyed() bool {
t.mu.Lock()
defer t.mu.Unlock()
return t.destroyed
}
func newTestCounter() *testCounter {
return &testCounter{destroyed: false}
}
func TestOneRef(t *testing.T) {
tc := newTestCounter()
tc.DecRef(context.Background())
if !tc.IsDestroyed() {
t.Errorf("object should have been destroyed")
}
}
func TestTwoRefs(t *testing.T) {
tc := newTestCounter()
tc.IncRef()
ctx := context.Background()
tc.DecRef(ctx)
tc.DecRef(ctx)
if !tc.IsDestroyed() {
t.Errorf("object should have been destroyed")
}
}
func TestMultiRefs(t *testing.T) {
tc := newTestCounter()
tc.IncRef()
ctx := context.Background()
tc.DecRef(ctx)
tc.IncRef()
tc.DecRef(ctx)
tc.DecRef(ctx)
if !tc.IsDestroyed() {
t.Errorf("object should have been destroyed")
}
}
func TestWeakRef(t *testing.T) {
tc := newTestCounter()
w := NewWeakRef(tc, nil)
ctx := context.Background()
// Try resolving.
if x := w.Get(); x == nil {
t.Errorf("weak reference didn't resolve: expected %v, got nil", tc)
} else {
x.DecRef(ctx)
}
// Try resolving again.
if x := w.Get(); x == nil {
t.Errorf("weak reference didn't resolve: expected %v, got nil", tc)
} else {
x.DecRef(ctx)
}
// Shouldn't be destroyed yet. (Can't continue if this fails.)
if tc.IsDestroyed() {
t.Fatalf("original object destroyed earlier than expected")
}
// Drop the original reference.
tc.DecRef(ctx)
// Assert destroyed.
if !tc.IsDestroyed() {
t.Errorf("original object not destroyed as expected")
}
// Shouldn't be anything.
if x := w.Get(); x != nil {
t.Errorf("weak reference resolved: expected nil, got %v", x)
}
}
func TestWeakRefDrop(t *testing.T) {
tc := newTestCounter()
w := NewWeakRef(tc, nil)
ctx := context.Background()
w.Drop(ctx)
// Just assert the list is empty.
if !tc.weakRefs.Empty() {
t.Errorf("weak reference not dropped")
}
// Drop the original reference.
tc.DecRef(ctx)
}
type testWeakRefUser struct {
weakRefGone func()
}
func (u *testWeakRefUser) WeakRefGone(ctx context.Context) {
u.weakRefGone()
}
func TestCallback(t *testing.T) {
called := false
tc := newTestCounter()
var w *WeakRef
w = NewWeakRef(tc, &testWeakRefUser{func() {
called = true
// Check that the weak ref has been zapped.
rc := w.obj.Load().(RefCounter)
if v := reflect.ValueOf(rc); v != reflect.Zero(v.Type()) {
t.Fatalf("Callback called with non-nil ptr")
}
// Check that we're not holding the mutex by acquiring and
// releasing it.
tc.mu.Lock()
tc.mu.Unlock()
}})
// Drop the original reference, this must trigger the callback.
ctx := context.Background()
tc.DecRef(ctx)
if !called {
t.Fatalf("Callback not called")
}
}
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