124 lines
2.3 KiB
Go
124 lines
2.3 KiB
Go
package main
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import (
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"sync/atomic"
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"testing"
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"time"
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"github.com/stretchr/testify/assert"
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)
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type RWMutex struct {
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// need to implement
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}
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func (m *RWMutex) Lock() {
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// need to implement
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}
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func (m *RWMutex) Unlock() {
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// need to implement
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}
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func (m *RWMutex) RLock() {
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// need to implement
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}
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func (m *RWMutex) RUnlock() {
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// need to implement
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}
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func TestRWMutexWithWriter(t *testing.T) {
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var mutex RWMutex
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mutex.Lock() // writer
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var mutualExlusionWithWriter atomic.Bool
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mutualExlusionWithWriter.Store(true)
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var mutualExlusionWithReader atomic.Bool
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mutualExlusionWithReader.Store(true)
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go func() {
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mutex.Lock() // another writer
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mutualExlusionWithWriter.Store(false)
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}()
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go func() {
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mutex.RLock() // another reader
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mutualExlusionWithReader.Store(false)
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}()
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time.Sleep(time.Second)
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assert.True(t, mutualExlusionWithWriter.Load())
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assert.True(t, mutualExlusionWithReader.Load())
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}
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func TestRWMutexWithReaders(t *testing.T) {
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var mutex RWMutex
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mutex.RLock() // reader
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var mutualExlusionWithWriter atomic.Bool
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mutualExlusionWithWriter.Store(true)
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go func() {
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mutex.Lock() // another writer
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mutualExlusionWithWriter.Store(false)
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}()
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time.Sleep(time.Second)
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assert.True(t, mutualExlusionWithWriter.Load())
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}
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func TestRWMutexMultipleReaders(t *testing.T) {
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var mutex RWMutex
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mutex.RLock() // reader
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var readersCount atomic.Int32
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readersCount.Add(1)
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go func() {
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mutex.RLock() // another reader
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readersCount.Add(1)
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}()
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go func() {
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mutex.RLock() // another reader
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readersCount.Add(1)
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}()
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time.Sleep(time.Second)
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assert.Equal(t, int32(3), readersCount.Load())
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}
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func TestRWMutexWithWriterPriority(t *testing.T) {
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var mutex RWMutex
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mutex.RLock() // reader
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var mutualExlusionWithWriter atomic.Bool
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mutualExlusionWithWriter.Store(true)
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var readersCount atomic.Int32
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readersCount.Add(1)
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go func() {
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mutex.Lock() // another writer is waiting for reader
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mutualExlusionWithWriter.Store(false)
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}()
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time.Sleep(time.Second)
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go func() {
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mutex.RLock() // another reader is waiting for a higher priority writer
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readersCount.Add(1)
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}()
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go func() {
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mutex.RLock() // another reader is waiting for a higher priority writer
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readersCount.Add(1)
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}()
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time.Sleep(time.Second)
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assert.True(t, mutualExlusionWithWriter.Load())
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assert.Equal(t, int32(1), readersCount.Load())
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}
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