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// Copyright 2016 CoreOS, Inc.
//
// 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 runtime
import (
"context"
"fmt"
"sync"
)
type Failpoint struct {
cmu sync.RWMutex
ctx context.Context
cancel context.CancelFunc
donec chan struct{}
released bool
mu sync.RWMutex
t *terms
}
func NewFailpoint(pkg, name string, goFailGo bool) *Failpoint {
fp := &Failpoint{}
if goFailGo {
fp.ctx, fp.cancel = context.WithCancel(context.Background())
fp.donec = make(chan struct{})
}
register(pkg+"/"+name, fp)
return fp
}
// Acquire gets evalutes the failpoint terms; if the failpoint
// is active, it will return a value. Otherwise, returns a non-nil error.
func (fp *Failpoint) Acquire() (interface{}, error) {
fp.mu.RLock()
if fp.t == nil {
fp.mu.RUnlock()
return nil, ErrDisabled
}
v, err := fp.t.eval()
if v == nil {
err = ErrDisabled
}
if err != nil {
fp.mu.RUnlock()
}
return v, err
}
// Release is called when the failpoint exists.
func (fp *Failpoint) Release() {
fp.cmu.RLock()
ctx := fp.ctx
donec := fp.donec
fp.cmu.RUnlock()
if ctx != nil && !fp.released {
<-ctx.Done()
select {
case <-donec:
default:
close(donec)
}
}
fp.mu.RUnlock()
}
// BadType is called when the failpoint evaluates to the wrong type.
func (fp *Failpoint) BadType(v interface{}, t string) {
fmt.Printf("failpoint: %q got value %v of type \"%T\" but expected type %q\n", fp.t.fpath, v, v, t)
}
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