forked from apache/mynewt-newtmgr
/
err_funnel.go
96 lines (79 loc) · 1.95 KB
/
err_funnel.go
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/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 nmxutil
import (
"sync"
"time"
)
type ErrLessFn func(a error, b error) bool
type ErrProcFn func(err error)
// Aggregates errors that occur close in time. The most severe error gets
// reported.
type ErrFunnel struct {
LessCb ErrLessFn
AccumDelay time.Duration
mtx sync.Mutex
resetMtx sync.Mutex
curErr error
errTimer *time.Timer
waiters [](chan error)
}
func (f *ErrFunnel) Insert(err error) {
if err == nil {
panic("ErrFunnel nil insert")
}
f.mtx.Lock()
defer f.mtx.Unlock()
if f.curErr == nil {
f.curErr = err
f.errTimer = time.AfterFunc(f.AccumDelay, func() {
f.timerExp()
})
} else {
if f.LessCb(f.curErr, err) {
if !f.errTimer.Stop() {
<-f.errTimer.C
}
f.curErr = err
f.errTimer.Reset(f.AccumDelay)
}
}
}
func (f *ErrFunnel) timerExp() {
f.mtx.Lock()
err := f.curErr
f.curErr = nil
waiters := f.waiters
f.waiters = nil
f.mtx.Unlock()
if err == nil {
panic("ErrFunnel timer expired but no error")
}
for _, w := range waiters {
w <- err
close(w)
}
}
func (f *ErrFunnel) Wait() chan error {
c := make(chan error)
f.mtx.Lock()
f.waiters = append(f.waiters, c)
f.mtx.Unlock()
return c
}