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|
package playwright
import (
"context"
"fmt"
"reflect"
"sync"
"sync/atomic"
"time"
)
type (
waiter struct {
mu sync.Mutex
timeout float64
fulfilled atomic.Bool
listeners []eventListener
errChan chan error
waitFunc func() (interface{}, error)
}
eventListener struct {
emitter EventEmitter
event string
handler interface{}
}
)
// RejectOnEvent sets the Waiter to return an error when an event occurs (and the predicate returns true)
func (w *waiter) RejectOnEvent(emitter EventEmitter, event string, err error, predicates ...interface{}) *waiter {
w.mu.Lock()
defer w.mu.Unlock()
if w.waitFunc != nil {
w.reject(fmt.Errorf("waiter: call RejectOnEvent before WaitForEvent"))
return w
}
handler := func(ev ...interface{}) {
if w.fulfilled.Load() {
return
}
if len(predicates) == 0 {
w.reject(err)
} else {
result := reflect.ValueOf(predicates[0]).Call([]reflect.Value{reflect.ValueOf(ev[0])})
if result[0].Bool() {
w.reject(err)
}
}
}
emitter.On(event, handler)
w.listeners = append(w.listeners, eventListener{
emitter: emitter,
event: event,
handler: handler,
})
return w
}
// WithTimeout sets timeout, in milliseconds, for the waiter. 0 means no timeout.
func (w *waiter) WithTimeout(timeout float64) *waiter {
w.mu.Lock()
defer w.mu.Unlock()
if w.waitFunc != nil {
w.reject(fmt.Errorf("waiter: please set timeout before WaitForEvent"))
return w
}
w.timeout = timeout
return w
}
// WaitForEvent sets the Waiter to return when an event occurs (and the predicate returns true)
func (w *waiter) WaitForEvent(emitter EventEmitter, event string, predicate interface{}) *waiter {
w.mu.Lock()
defer w.mu.Unlock()
if w.waitFunc != nil {
w.reject(fmt.Errorf("waiter: WaitForEvent can only be called once"))
return w
}
evChan := make(chan interface{}, 1)
handler := w.createHandler(evChan, predicate)
ctx, cancel := context.WithCancel(context.Background())
if w.timeout != 0 {
timeout := w.timeout
go func() {
select {
case <-time.After(time.Duration(timeout) * time.Millisecond):
err := fmt.Errorf("%w:Timeout %.2fms exceeded.", ErrTimeout, timeout)
w.reject(err)
return
case <-ctx.Done():
return
}
}()
}
emitter.On(event, handler)
w.listeners = append(w.listeners, eventListener{
emitter: emitter,
event: event,
handler: handler,
})
w.waitFunc = func() (interface{}, error) {
var (
err error
val interface{}
)
select {
case err = <-w.errChan:
break
case val = <-evChan:
break
}
cancel()
w.mu.Lock()
defer w.mu.Unlock()
for _, l := range w.listeners {
l.emitter.RemoveListener(l.event, l.handler)
}
close(evChan)
if err != nil {
return nil, err
}
return val, nil
}
return w
}
// Wait waits for the waiter to return. It needs to call WaitForEvent once first.
func (w *waiter) Wait() (interface{}, error) {
if w.waitFunc == nil {
return nil, fmt.Errorf("waiter: call WaitForEvent first")
}
return w.waitFunc()
}
// RunAndWait waits for the waiter to return after calls func.
func (w *waiter) RunAndWait(cb func() error) (interface{}, error) {
if w.waitFunc == nil {
return nil, fmt.Errorf("waiter: call WaitForEvent first")
}
if cb != nil {
if err := cb(); err != nil {
w.errChan <- err
}
}
return w.waitFunc()
}
func (w *waiter) createHandler(evChan chan<- interface{}, predicate interface{}) func(...interface{}) {
return func(ev ...interface{}) {
if w.fulfilled.Load() {
return
}
if predicate == nil || reflect.ValueOf(predicate).IsNil() {
w.fulfilled.Store(true)
if len(ev) == 1 {
evChan <- ev[0]
} else {
evChan <- nil
}
} else {
result := reflect.ValueOf(predicate).Call([]reflect.Value{reflect.ValueOf(ev[0])})
if result[0].Bool() {
w.fulfilled.Store(true)
evChan <- ev[0]
}
}
}
}
func (w *waiter) reject(err error) {
w.fulfilled.Store(true)
w.errChan <- err
}
func newWaiter() *waiter {
w := &waiter{
errChan: make(chan error, 1),
}
return w
}
|
