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How to use Close method of event Package

Best Testkube code snippet using event.Close

reader.go

Source:reader.go

...11	"github.com/cilium/ebpf/internal"12	"github.com/cilium/ebpf/internal/unix"13)14var (15	ErrClosed = errors.New("perf reader was closed")16	errEOR    = errors.New("end of ring")17)18// perfEventHeader must match 'struct perf_event_header` in <linux/perf_event.h>.19type perfEventHeader struct {20	Type uint3221	Misc uint1622	Size uint1623}24func addToEpoll(epollfd, fd int, cpu int) error {25	if int64(cpu) > math.MaxInt32 {26		return fmt.Errorf("unsupported CPU number: %d", cpu)27	}28	// The representation of EpollEvent isn't entirely accurate.29	// Pad is fully useable, not just padding. Hence we stuff the30	// CPU in there, which allows us to use a slice to access31	// the correct perf ring.32	event := unix.EpollEvent{33		Events: unix.EPOLLIN,34		Fd:     int32(fd),35		Pad:    int32(cpu),36	}37	if err := unix.EpollCtl(epollfd, unix.EPOLL_CTL_ADD, fd, &event); err != nil {38		return fmt.Errorf("can't add fd to epoll: %v", err)39	}40	return nil41}42func cpuForEvent(event *unix.EpollEvent) int {43	return int(event.Pad)44}45// Record contains either a sample or a counter of the46// number of lost samples.47type Record struct {48	// The CPU this record was generated on.49	CPU int50	// The data submitted via bpf_perf_event_output.51	// Due to a kernel bug, this can contain between 0 and 7 bytes of trailing52	// garbage from the ring depending on the input sample's length.53	RawSample []byte54	// The number of samples which could not be output, since55	// the ring buffer was full.56	LostSamples uint6457}58// NB: Has to be preceded by a call to ring.loadHead.59func readRecordFromRing(ring *perfEventRing) (Record, error) {60	defer ring.writeTail()61	return readRecord(ring, ring.cpu)62}63func readRecord(rd io.Reader, cpu int) (Record, error) {64	var header perfEventHeader65	err := binary.Read(rd, internal.NativeEndian, &header)66	if err == io.EOF {67		return Record{}, errEOR68	}69	if err != nil {70		return Record{}, fmt.Errorf("can't read event header: %v", err)71	}72	switch header.Type {73	case unix.PERF_RECORD_LOST:74		lost, err := readLostRecords(rd)75		return Record{CPU: cpu, LostSamples: lost}, err76	case unix.PERF_RECORD_SAMPLE:77		sample, err := readRawSample(rd)78		return Record{CPU: cpu, RawSample: sample}, err79	default:80		return Record{}, &unknownEventError{header.Type}81	}82}83func readLostRecords(rd io.Reader) (uint64, error) {84	// lostHeader must match 'struct perf_event_lost in kernel sources.85	var lostHeader struct {86		ID   uint6487		Lost uint6488	}89	err := binary.Read(rd, internal.NativeEndian, &lostHeader)90	if err != nil {91		return 0, fmt.Errorf("can't read lost records header: %v", err)92	}93	return lostHeader.Lost, nil94}95func readRawSample(rd io.Reader) ([]byte, error) {96	// This must match 'struct perf_event_sample in kernel sources.97	var size uint3298	if err := binary.Read(rd, internal.NativeEndian, &size); err != nil {99		return nil, fmt.Errorf("can't read sample size: %v", err)100	}101	data := make([]byte, int(size))102	if _, err := io.ReadFull(rd, data); err != nil {103		return nil, fmt.Errorf("can't read sample: %v", err)104	}105	return data, nil106}107// Reader allows reading bpf_perf_event_output108// from user space.109type Reader struct {110	// mu protects read/write access to the Reader structure with the111	// exception of 'pauseFds', which is protected by 'pauseMu'.112	// If locking both 'mu' and 'pauseMu', 'mu' must be locked first.113	mu sync.Mutex114	// Closing a PERF_EVENT_ARRAY removes all event fds115	// stored in it, so we keep a reference alive.116	array *ebpf.Map117	rings []*perfEventRing118	epollFd     int119	epollEvents []unix.EpollEvent120	epollRings  []*perfEventRing121	// Eventfds for closing122	closeFd int123	// Ensure we only close once124	closeOnce sync.Once125	// pauseFds are a copy of the fds in 'rings', protected by 'pauseMu'.126	// These allow Pause/Resume to be executed independently of any ongoing127	// Read calls, which would otherwise need to be interrupted.128	pauseMu  sync.Mutex129	pauseFds []int130}131// ReaderOptions control the behaviour of the user132// space reader.133type ReaderOptions struct {134	// The number of written bytes required in any per CPU buffer before135	// Read will process data. Must be smaller than PerCPUBuffer.136	// The default is to start processing as soon as data is available.137	Watermark int138}139// NewReader creates a new reader with default options.140//141// array must be a PerfEventArray. perCPUBuffer gives the size of the142// per CPU buffer in bytes. It is rounded up to the nearest multiple143// of the current page size.144func NewReader(array *ebpf.Map, perCPUBuffer int) (*Reader, error) {145	return NewReaderWithOptions(array, perCPUBuffer, ReaderOptions{})146}147// NewReaderWithOptions creates a new reader with the given options.148func NewReaderWithOptions(array *ebpf.Map, perCPUBuffer int, opts ReaderOptions) (pr *Reader, err error) {149	if perCPUBuffer < 1 {150		return nil, errors.New("perCPUBuffer must be larger than 0")151	}152	epollFd, err := unix.EpollCreate1(unix.EPOLL_CLOEXEC)153	if err != nil {154		return nil, fmt.Errorf("can't create epoll fd: %v", err)155	}156	var (157		fds      = []int{epollFd}158		nCPU     = int(array.MaxEntries())159		rings    = make([]*perfEventRing, 0, nCPU)160		pauseFds = make([]int, 0, nCPU)161	)162	defer func() {163		if err != nil {164			for _, fd := range fds {165				unix.Close(fd)166			}167			for _, ring := range rings {168				if ring != nil {169					ring.Close()170				}171			}172		}173	}()174	// bpf_perf_event_output checks which CPU an event is enabled on,175	// but doesn't allow using a wildcard like -1 to specify "all CPUs".176	// Hence we have to create a ring for each CPU.177	for i := 0; i < nCPU; i++ {178		ring, err := newPerfEventRing(i, perCPUBuffer, opts.Watermark)179		if errors.Is(err, unix.ENODEV) {180			// The requested CPU is currently offline, skip it.181			rings = append(rings, nil)182			pauseFds = append(pauseFds, -1)183			continue184		}185		if err != nil {186			return nil, fmt.Errorf("failed to create perf ring for CPU %d: %v", i, err)187		}188		rings = append(rings, ring)189		pauseFds = append(pauseFds, ring.fd)190		if err := addToEpoll(epollFd, ring.fd, len(rings)-1); err != nil {191			return nil, err192		}193	}194	closeFd, err := unix.Eventfd(0, unix.O_CLOEXEC|unix.O_NONBLOCK)195	if err != nil {196		return nil, err197	}198	fds = append(fds, closeFd)199	if err := addToEpoll(epollFd, closeFd, -1); err != nil {200		return nil, err201	}202	array, err = array.Clone()203	if err != nil {204		return nil, err205	}206	pr = &Reader{207		array:   array,208		rings:   rings,209		epollFd: epollFd,210		// Allocate extra event for closeFd211		epollEvents: make([]unix.EpollEvent, len(rings)+1),212		epollRings:  make([]*perfEventRing, 0, len(rings)),213		closeFd:     closeFd,214		pauseFds:    pauseFds,215	}216	if err = pr.Resume(); err != nil {217		return nil, err218	}219	runtime.SetFinalizer(pr, (*Reader).Close)220	return pr, nil221}222// Close frees resources used by the reader.223//224// It interrupts calls to Read.225//226// Calls to perf_event_output from eBPF programs will return227// ENOENT after calling this method.228func (pr *Reader) Close() error {229	var err error230	pr.closeOnce.Do(func() {231		runtime.SetFinalizer(pr, nil)232		// Interrupt Read() via the event fd.233		var value [8]byte234		internal.NativeEndian.PutUint64(value[:], 1)235		_, err = unix.Write(pr.closeFd, value[:])236		if err != nil {237			err = fmt.Errorf("can't write event fd: %v", err)238			return239		}240		// Acquire the locks. This ensures that Read, Pause and Resume241		// aren't running.242		pr.mu.Lock()243		defer pr.mu.Unlock()244		pr.pauseMu.Lock()245		defer pr.pauseMu.Unlock()246		unix.Close(pr.epollFd)247		unix.Close(pr.closeFd)248		pr.epollFd, pr.closeFd = -1, -1249		// Close rings250		for _, ring := range pr.rings {251			if ring != nil {252				ring.Close()253			}254		}255		pr.rings = nil256		pr.pauseFds = nil257		pr.array.Close()258	})259	if err != nil {260		return fmt.Errorf("close PerfReader: %w", err)261	}262	return nil263}264// Read the next record from the perf ring buffer.265//266// The function blocks until there are at least Watermark bytes in one267// of the per CPU buffers. Records from buffers below the Watermark268// are not returned.269//270// Records can contain between 0 and 7 bytes of trailing garbage from the ring271// depending on the input sample's length.272//273// Calling Close interrupts the function.274func (pr *Reader) Read() (Record, error) {275	pr.mu.Lock()276	defer pr.mu.Unlock()277	if pr.epollFd == -1 {278		return Record{}, fmt.Errorf("%w", ErrClosed)279	}280	for {281		if len(pr.epollRings) == 0 {282			nEvents, err := unix.EpollWait(pr.epollFd, pr.epollEvents, -1)283			if temp, ok := err.(temporaryError); ok && temp.Temporary() {284				// Retry the syscall if we we're interrupted, see https://github.com/golang/go/issues/20400285				continue286			}287			if err != nil {288				return Record{}, err289			}290			for _, event := range pr.epollEvents[:nEvents] {291				if int(event.Fd) == pr.closeFd {292					return Record{}, fmt.Errorf("%w", ErrClosed)293				}294				ring := pr.rings[cpuForEvent(&event)]295				pr.epollRings = append(pr.epollRings, ring)296				// Read the current head pointer now, not every time297				// we read a record. This prevents a single fast producer298				// from keeping the reader busy.299				ring.loadHead()300			}301		}302		// Start at the last available event. The order in which we303		// process them doesn't matter, and starting at the back allows304		// resizing epollRings to keep track of processed rings.305		record, err := readRecordFromRing(pr.epollRings[len(pr.epollRings)-1])306		if err == errEOR {307			// We've emptied the current ring buffer, process308			// the next one.309			pr.epollRings = pr.epollRings[:len(pr.epollRings)-1]310			continue311		}312		return record, err313	}314}315// Pause stops all notifications from this Reader.316//317// While the Reader is paused, any attempts to write to the event buffer from318// BPF programs will return -ENOENT.319//320// Subsequent calls to Read will block until a call to Resume.321func (pr *Reader) Pause() error {322	pr.pauseMu.Lock()323	defer pr.pauseMu.Unlock()324	if pr.pauseFds == nil {325		return fmt.Errorf("%w", ErrClosed)326	}327	for i := range pr.pauseFds {328		if err := pr.array.Delete(uint32(i)); err != nil && !errors.Is(err, ebpf.ErrKeyNotExist) {329			return fmt.Errorf("could't delete event fd for CPU %d: %w", i, err)330		}331	}332	return nil333}334// Resume allows this perf reader to emit notifications.335//336// Subsequent calls to Read will block until the next event notification.337func (pr *Reader) Resume() error {338	pr.pauseMu.Lock()339	defer pr.pauseMu.Unlock()340	if pr.pauseFds == nil {341		return fmt.Errorf("%w", ErrClosed)342	}343	for i, fd := range pr.pauseFds {344		if fd == -1 {345			continue346		}347		if err := pr.array.Put(uint32(i), uint32(fd)); err != nil {348			return fmt.Errorf("couldn't put event fd %d for CPU %d: %w", fd, i, err)349		}350	}351	return nil352}353type temporaryError interface {354	Temporary() bool355}356// IsClosed returns true if the error occurred because357// a Reader was closed.358//359// Deprecated: use errors.Is(err, ErrClosed) instead.360func IsClosed(err error) bool {361	return errors.Is(err, ErrClosed)362}363type unknownEventError struct {364	eventType uint32365}366func (uev *unknownEventError) Error() string {367	return fmt.Sprintf("unknown event type: %d", uev.eventType)368}369// IsUnknownEvent returns true if the error occurred370// because an unknown event was submitted to the perf event ring.371func IsUnknownEvent(err error) bool {372	var uee *unknownEventError373	return errors.As(err, &uee)374}...

event.go

Source:event.go

...7	"time"8)9var (10	ErrEvtWaitTimeout = errors.New("event wait time out")11	ErrEvtClosed      = errors.New("event closed")12)13type Event struct {14	C         chan byte15	chanClose chan byte16}17func NewEvent() *Event {18	return &Event{19		C:         make(chan byte, 1),20		chanClose: make(chan byte),21	}22}23// Send event.24func (e *Event) Send() error {25	select {26	case <-e.chanClose:27		return ErrEvtClosed28	default:29		select {30		case e.C <- 1:31		default:32		}33	}34	return nil35	// if e.bClosed {36	// 	return ErrEvtClosed37	// }38	// if len(e.C) == 0 {39	// 	e.C <- 140	// }41	// return nil42}43// Wait event.44func (e *Event) Wait() error {45	select {46	case <-e.chanClose:47		return ErrEvtClosed48	case <-e.C:49	}50	return nil51	// _, ok := <-e.C52	// if ok {53	// 	return nil54	// }55	// return ErrEvtClosed56}57// Close the event.58func (e *Event) Close() {59	select {60	case <-e.chanClose:61		return62	default:63		close(e.chanClose)64	}65	// if !e.bClosed {66	// 	e.bClosed = true67	// 	close(e.C)68	// }69}70// Wait event until timeout.71// @param timeoutMSec, timeout after millisecond. 0 mean check at once, only can use in one waiter scene.72// @return error, ErrEvtWaitTimeout mean timeout.73func (e *Event) WaitUntilTimeout(timeoutMSec uint32) error {74	if timeoutMSec == 0 {75		select {76		case <-e.C:77			return nil78		default:79			return ErrEvtWaitTimeout80		}81	}82	var err error = nil83	t := time.NewTimer(time.Millisecond * time.Duration(timeoutMSec))84	select {85	case <-e.chanClose:86		t.Stop()87		err = ErrEvtClosed88	case <-e.C:89		t.Stop()90	case <-t.C:91		err = ErrEvtWaitTimeout92	}93	return err94}...

Using AI Code Generation

1import (2func main() {3	err := sdl.Init(sdl.INIT_EVERYTHING)4	if err != nil {5		fmt.Println(err)6	}7	defer sdl.Quit()8	window, err := sdl.CreateWindow("Tutorial 2", sdl.WINDOWPOS_UNDEFINED, sdl.WINDOWPOS_UNDEFINED, 800, 600, sdl.WINDOW_SHOWN)9	if err != nil {10		fmt.Println(err)11	}12	defer window.Destroy()13	surface, err := window.GetSurface()14	if err != nil {15		fmt.Println(err)16	}17	rect := sdl.Rect{0, 0, 200, 200}18	surface.FillRect(&rect, 0xffff0000)19	window.UpdateSurface()20	for running {21		for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {22			switch t := event.(type) {23				fmt.Println("Quit")24			}25		}26	}27}

Using AI Code Generation

1import (2func main() {3gtk.Init(nil)4win, _ := gtk.WindowNew(gtk.WINDOW_TOPLEVEL)5win.SetTitle("Hello, gotk3!")6win.Connect("destroy", func() {7gtk.MainQuit()8})9win.ShowAll()10gtk.Main()11}12import (13func main() {14gtk.Init(nil)15win, _ := gtk.WindowNew(gtk.WINDOW_TOPLEVEL)16win.SetTitle("Hello, gotk3!")17win.Connect("destroy", func() {18gtk.MainQuit()19})20win.ShowAll()21gtk.Main()22}23import (24func main() {25gtk.Init(nil)26win, _ := gtk.WindowNew(gtk.WINDOW_TOPLEVEL)27win.SetTitle("Hello, gotk3!")28win.Connect("destroy", func() {29gtk.MainQuit()30})31win.ShowAll()32gtk.Main()33}34import (35func main() {36gtk.Init(nil)37win, _ := gtk.WindowNew(gtk.WINDOW_TOPLEVEL)38win.SetTitle("Hello, gotk3!")39win.Connect("destroy", func() {40gtk.MainQuit()41})42win.ShowAll()43gtk.Main()44}45import (46func main() {47gtk.Init(nil)48win, _ := gtk.WindowNew(gtk.WINDOW_TOPLEVEL)49win.SetTitle("Hello, gotk3!")50win.Connect("destroy", func() {51gtk.MainQuit()52})53win.ShowAll()54gtk.Main()55}56import (57func main() {58gtk.Init(nil)59win, _ := gtk.WindowNew(gtk.WINDOW_TOP

Using AI Code Generation

1import (2func loop() {3    giu.SingleWindow("Hello").Layout(4        giu.Button("Click me").OnClick(func() {5            fmt.Println("Clicked")6        }),7}8func main() {9    w := giu.NewMasterWindow("Hello", 400, 200, 0)10    w.Main(loop)11}12import (13func loop() {14    giu.SingleWindow("Hello").Layout(15        giu.Button("Click me").OnClick(func() {16            fmt.Println("Clicked")17        }),18}19func main() {20    w := giu.NewMasterWindow("Hello", 400, 200, 0)21    w.Main(loop)22}23import (24func loop() {25    giu.SingleWindow("Hello").Layout(26        giu.Button("Click me").OnClick(func() {27            fmt.Println("Clicked")28        }),29}30func main() {31    w := giu.NewMasterWindow("Hello", 400, 200, 0)32    w.Main(loop)33}34import (35func loop() {36    giu.SingleWindow("Hello").Layout(37        giu.Button("Click me").OnClick(func() {38            fmt.Println("Clicked")39        }),40}41func main() {42    w := giu.NewMasterWindow("Hello", 400, 200, 0)43    w.Main(loop)44}45import (

Using AI Code Generation

1import (2type Event struct {3}4func NewEvent(name string) *Event {5    return &Event{name: name, time: time.Now()}6}7func (e *Event) Close() {8    fmt.Printf("Event %s took %s9", e.name, time.Since(e.time))10}11func main() {12    e := NewEvent("my event")13    defer e.Close()14    time.Sleep(time.Duration(rand.Intn(1000)) * time.Millisecond)15}

Using AI Code Generation

1import (2type Event struct {3}4func (e *Event) Close() {5	fmt.Println("closing")6}7func main() {8	size := int64(0)9	event := Event{path, name, size, hash, time, eventType}10	defer event.Close()11	fmt.Println("doing something")12}13import (14type Event struct {15}16func (e *Event) Close() {17	fmt.Println("closing")18}19func main() {

Using AI Code Generation

1import (2func main() {3	robotgo.EventEnd()4	fmt.Println("EventEnd")5}6import (7func main() {8	robotgo.EventEnd()9	robotgo.EventEnd()10	fmt.Println("EventEnd")11}12import (13func main() {14	robotgo.EventEnd()15	robotgo.EventEnd()16	fmt.Println("EventEnd")17}18import (19func main() {20	robotgo.EventEnd()21	robotgo.EventEnd()22	fmt.Println("EventEnd")23}24import (25func main() {26	robotgo.EventEnd()27	robotgo.EventEnd()28	fmt.Println("EventEnd")29}30import (31func main() {32	robotgo.EventEnd()33	robotgo.EventEnd()34	fmt.Println("EventEnd")35}36import (37func main() {38	robotgo.EventEnd()39	robotgo.EventEnd()40	fmt.Println("EventEnd")41}42import (43func main() {44	robotgo.EventEnd()45	robotgo.EventEnd()

Using AI Code Generation

1func main() {2    e := event.New()3    e.On("greet", func(s string) {4        fmt.Println("Hello", s)5    })6    e.Fire("greet", "John")7    e.Close()8}

Using AI Code Generation

1import (2func main() {3	event := NewEvent()4	ch := make(chan int)5	event.Register(ch)6	event.Trigger(1)7	time.Sleep(3 * time.Second)8	event.Close()9	time.Sleep(1 * time.Second)10	event.Trigger(2)11	time.Sleep(1 * time.Second)12}

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