// Copyright (c) 2015-2021 MinIO, Inc.//// This file is part of MinIO Object Storage stack//// This program is free software: you can redistribute it and/or modify// it under the terms of the GNU Affero General Public License as published by// the Free Software Foundation, either version 3 of the License, or// (at your option) any later version.//// This program is distributed in the hope that it will be useful// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the// GNU Affero General Public License for more details.//// You should have received a copy of the GNU Affero General Public License// along with this program.  If not, see <http://www.gnu.org/licenses/>. package dsync import (	"context"	"fmt"	"runtime"	"sync/atomic"	"testing"	"time") const (	id     = "1234-5678"	source = "main.go") func testSimpleWriteLock(t *testing.T, duration time.Duration) (locked bool) {	drwm := NewDRWMutex(ds, "simplelock") 	ctx1, cancel1 := context.WithCancel(context.Background())	if !drwm.GetRLock(ctx1, cancel1, id, source, Options{Timeout: time.Second}) {		panic("Failed to acquire read lock")	}	// fmt.Println("1st read lock acquired, waiting...") 	ctx2, cancel2 := context.WithCancel(context.Background())	if !drwm.GetRLock(ctx2, cancel2, id, source, Options{Timeout: time.Second}) {		panic("Failed to acquire read lock")	}	// fmt.Println("2nd read lock acquired, waiting...") 	go func() {		time.Sleep(2 * testDrwMutexAcquireTimeout)		drwm.RUnlock()		// fmt.Println("1st read lock released, waiting...")	}() 	go func() {		time.Sleep(3 * testDrwMutexAcquireTimeout)		drwm.RUnlock()		// fmt.Println("2nd read lock released, waiting...")	}() 	// fmt.Println("Trying to acquire write lock, waiting...")	ctx3, cancel3 := context.WithCancel(context.Background())	locked = drwm.GetLock(ctx3, cancel3, id, source, Options{Timeout: duration})	if locked {		// fmt.Println("Write lock acquired, waiting...")		time.Sleep(testDrwMutexAcquireTimeout) 		drwm.Unlock()	}	// fmt.Println("Write lock failed due to timeout")	return} func TestSimpleWriteLockAcquired(t *testing.T) {	locked := testSimpleWriteLock(t, 10*testDrwMutexAcquireTimeout) 	expected := true	if locked != expected {		t.Errorf("TestSimpleWriteLockAcquired(): \nexpected %#v\ngot      %#v", expected, locked)	}} func TestSimpleWriteLockTimedOut(t *testing.T) {	locked := testSimpleWriteLock(t, testDrwMutexAcquireTimeout) 	expected := false	if locked != expected {		t.Errorf("TestSimpleWriteLockTimedOut(): \nexpected %#v\ngot      %#v", expected, locked)	}} func testDualWriteLock(t *testing.T, duration time.Duration) (locked bool) {	drwm := NewDRWMutex(ds, "duallock") 	// fmt.Println("Getting initial write lock")	ctx1, cancel1 := context.WithCancel(context.Background())	if !drwm.GetLock(ctx1, cancel1, id, source, Options{Timeout: time.Second}) {		panic("Failed to acquire initial write lock")	} 	go func() {		time.Sleep(3 * testDrwMutexAcquireTimeout)		drwm.Unlock()		// fmt.Println("Initial write lock released, waiting...")	}() 	// fmt.Println("Trying to acquire 2nd write lock, waiting...")	ctx2, cancel2 := context.WithCancel(context.Background())	locked = drwm.GetLock(ctx2, cancel2, id, source, Options{Timeout: duration})	if locked {		// fmt.Println("2nd write lock acquired, waiting...")		time.Sleep(testDrwMutexAcquireTimeout) 		drwm.Unlock()	}	// fmt.Println("2nd write lock failed due to timeout")	return} func TestDualWriteLockAcquired(t *testing.T) {	locked := testDualWriteLock(t, 10*testDrwMutexAcquireTimeout) 	expected := true	if locked != expected {		t.Errorf("TestDualWriteLockAcquired(): \nexpected %#v\ngot      %#v", expected, locked)	}} func TestDualWriteLockTimedOut(t *testing.T) {	locked := testDualWriteLock(t, testDrwMutexAcquireTimeout) 	expected := false	if locked != expected {		t.Errorf("TestDualWriteLockTimedOut(): \nexpected %#v\ngot      %#v", expected, locked)	}} // Test cases below are copied 1 to 1 from sync/rwmutex_test.go (adapted to use DRWMutex) // Borrowed from rwmutex_test.gofunc parallelReader(ctx context.Context, m *DRWMutex, clocked, cunlock, cdone chan bool) {	if m.GetRLock(ctx, nil, id, source, Options{Timeout: time.Second}) {		clocked <- true		<-cunlock		m.RUnlock()		cdone <- true	}} // Borrowed from rwmutex_test.gofunc doTestParallelReaders(numReaders, gomaxprocs int) {	runtime.GOMAXPROCS(gomaxprocs)	m := NewDRWMutex(ds, "test-parallel") 	clocked := make(chan bool)	cunlock := make(chan bool)	cdone := make(chan bool)	for i := 0; i < numReaders; i++ {		go parallelReader(context.Background(), m, clocked, cunlock, cdone)	}	// Wait for all parallel RLock()s to succeed.	for i := 0; i < numReaders; i++ {		<-clocked	}	for i := 0; i < numReaders; i++ {		cunlock <- true	}	// Wait for the goroutines to finish.	for i := 0; i < numReaders; i++ {		<-cdone	}} // Borrowed from rwmutex_test.gofunc TestParallelReaders(t *testing.T) {	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(-1))	doTestParallelReaders(1, 4)	doTestParallelReaders(3, 4)	doTestParallelReaders(4, 2)} // Borrowed from rwmutex_test.gofunc reader(rwm *DRWMutex, numIterations int, activity *int32, cdone chan bool) {	for i := 0; i < numIterations; i++ {		if rwm.GetRLock(context.Background(), nil, id, source, Options{Timeout: time.Second}) {			n := atomic.AddInt32(activity, 1)			if n < 1 || n >= 10000 {				panic(fmt.Sprintf("wlock(%d)\n", n))			}			for i := 0; i < 100; i++ {			}			atomic.AddInt32(activity, -1)			rwm.RUnlock()		}	}	cdone <- true} // Borrowed from rwmutex_test.gofunc writer(rwm *DRWMutex, numIterations int, activity *int32, cdone chan bool) {	for i := 0; i < numIterations; i++ {		if rwm.GetLock(context.Background(), nil, id, source, Options{Timeout: time.Second}) {			n := atomic.AddInt32(activity, 10000)			if n != 10000 {				panic(fmt.Sprintf("wlock(%d)\n", n))			}			for i := 0; i < 100; i++ {			}			atomic.AddInt32(activity, -10000)			rwm.Unlock()		}	}	cdone <- true} // Borrowed from rwmutex_test.gofunc hammerRWMutex(t *testing.T, gomaxprocs, numReaders, numIterations int) {	t.Run(fmt.Sprintf("%d-%d-%d", gomaxprocs, numReaders, numIterations), func(t *testing.T) {		runtime.GOMAXPROCS(gomaxprocs)		// Number of active readers + 10000 * number of active writers.		var activity int32		rwm := NewDRWMutex(ds, "test")		cdone := make(chan bool)		go writer(rwm, numIterations, &activity, cdone)		var i int		for i = 0; i < numReaders/2; i++ {			go reader(rwm, numIterations, &activity, cdone)		}		go writer(rwm, numIterations, &activity, cdone)		for ; i < numReaders; i++ {			go reader(rwm, numIterations, &activity, cdone)		}		// Wait for the 2 writers and all readers to finish.		for i := 0; i < 2+numReaders; i++ {			<-cdone		}	})} // Borrowed from rwmutex_test.gofunc TestRWMutex(t *testing.T) {	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(-1))	n := 100	if testing.Short() {		n = 5	}	hammerRWMutex(t, 1, 1, n)	hammerRWMutex(t, 1, 3, n)	hammerRWMutex(t, 1, 10, n)	hammerRWMutex(t, 4, 1, n)	hammerRWMutex(t, 4, 3, n)	hammerRWMutex(t, 4, 10, n)	hammerRWMutex(t, 10, 1, n)	hammerRWMutex(t, 10, 3, n)	hammerRWMutex(t, 10, 10, n)	hammerRWMutex(t, 10, 5, n)} // Borrowed from rwmutex_test.gofunc TestUnlockPanic(t *testing.T) {	defer func() {		if recover() == nil {			t.Fatalf("unlock of unlocked RWMutex did not panic")		}	}()	mu := NewDRWMutex(ds, "test")	mu.Unlock()} // Borrowed from rwmutex_test.gofunc TestUnlockPanic2(t *testing.T) {	mu := NewDRWMutex(ds, "test-unlock-panic-2")	defer func() {		if recover() == nil {			t.Fatalf("unlock of unlocked RWMutex did not panic")		}		mu.RUnlock() // Unlock, so -test.count > 1 works	}()	mu.RLock(id, source)	mu.Unlock()} // Borrowed from rwmutex_test.gofunc TestRUnlockPanic(t *testing.T) {	defer func() {		if recover() == nil {			t.Fatalf("read unlock of unlocked RWMutex did not panic")		}	}()	mu := NewDRWMutex(ds, "test")	mu.RUnlock()} // Borrowed from rwmutex_test.gofunc TestRUnlockPanic2(t *testing.T) {	mu := NewDRWMutex(ds, "test-runlock-panic-2")	defer func() {		if recover() == nil {			t.Fatalf("read unlock of unlocked RWMutex did not panic")		}		mu.Unlock() // Unlock, so -test.count > 1 works	}()	mu.Lock(id, source)	mu.RUnlock()} // Borrowed from rwmutex_test.gofunc benchmarkRWMutex(b *testing.B, localWork, writeRatio int) {	b.ResetTimer()	b.ReportAllocs() 	rwm := NewDRWMutex(ds, "test")	b.RunParallel(func(pb *testing.PB) {		foo := 0		for pb.Next() {			foo++			if foo%writeRatio == 0 {				rwm.Lock(id, source)				rwm.Unlock()			} else {				rwm.RLock(id, source)				for i := 0; i != localWork; i++ {					foo *= 2					foo /= 2				}				rwm.RUnlock()			}		}		_ = foo	})} // Borrowed from rwmutex_test.gofunc BenchmarkRWMutexWrite100(b *testing.B) {	benchmarkRWMutex(b, 0, 100)} // Borrowed from rwmutex_test.gofunc BenchmarkRWMutexWrite10(b *testing.B) {	benchmarkRWMutex(b, 0, 10)} // Borrowed from rwmutex_test.gofunc BenchmarkRWMutexWorkWrite100(b *testing.B) {	benchmarkRWMutex(b, 100, 100)} // Borrowed from rwmutex_test.gofunc BenchmarkRWMutexWorkWrite10(b *testing.B) {	benchmarkRWMutex(b, 100, 10)}