forked from mirror/ants
226 lines
5.3 KiB
Go
226 lines
5.3 KiB
Go
// MIT License
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// Copyright (c) 2018 Andy Pan
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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package ants
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import (
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"math"
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"sync"
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"sync/atomic"
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"time"
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)
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type sig struct{}
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type f func() error
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// Pool accept the tasks from client,it limits the total
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// of goroutines to a given number by recycling goroutines.
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type Pool struct {
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// capacity of the pool.
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capacity int32
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// running is the number of the currently running goroutines.
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running int32
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// expiryDuration set the expired time (second) of every worker.
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expiryDuration time.Duration
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// freeSignal is used to notice pool there are available
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// workers which can be sent to work.
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freeSignal chan sig
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// workers is a slice that store the available workers.
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workers []*Worker
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// release is used to notice the pool to closed itself.
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release chan sig
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// lock for synchronous operation
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lock sync.Mutex
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once sync.Once
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}
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func (p *Pool) monitorAndClear() {
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heartbeat := time.NewTicker(p.expiryDuration)
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go func() {
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for range heartbeat.C {
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currentTime := time.Now()
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p.lock.Lock()
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idleWorkers := p.workers
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if len(idleWorkers) == 0 && p.Running() == 0 && len(p.release) > 0 {
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p.lock.Unlock()
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return
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}
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n := 0
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for i, w := range idleWorkers {
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if currentTime.Sub(w.recycleTime) <= p.expiryDuration {
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break
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}
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n = i
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<-p.freeSignal
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w.task <- nil
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idleWorkers[i] = nil
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}
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if n > 0 {
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n++
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p.workers = idleWorkers[n:]
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}
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p.lock.Unlock()
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}
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}()
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}
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// NewPool generates a instance of ants pool
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func NewPool(size int) (*Pool, error) {
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return NewTimingPool(size, DefaultCleanIntervalTime)
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}
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// NewTimingPool generates a instance of ants pool with a custom timed task
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func NewTimingPool(size, expiry int) (*Pool, error) {
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if size <= 0 {
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return nil, ErrInvalidPoolSize
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}
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if expiry <= 0 {
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return nil, ErrInvalidPoolExpiry
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}
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p := &Pool{
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capacity: int32(size),
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freeSignal: make(chan sig, math.MaxInt32),
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release: make(chan sig, 1),
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expiryDuration: time.Duration(expiry) * time.Second,
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}
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p.monitorAndClear()
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return p, nil
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}
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//-------------------------------------------------------------------------
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// Submit submit a task to pool
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func (p *Pool) Submit(task f) error {
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if len(p.release) > 0 {
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return ErrPoolClosed
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}
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w := p.getWorker()
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w.task <- task
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return nil
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}
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// Running returns the number of the currently running goroutines
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func (p *Pool) Running() int {
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return int(atomic.LoadInt32(&p.running))
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}
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// Free returns the available goroutines to work
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func (p *Pool) Free() int {
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return int(atomic.LoadInt32(&p.capacity) - atomic.LoadInt32(&p.running))
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}
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// Cap returns the capacity of this pool
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func (p *Pool) Cap() int {
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return int(atomic.LoadInt32(&p.capacity))
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}
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// ReSize change the capacity of this pool
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func (p *Pool) ReSize(size int) {
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if size == p.Cap() {
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return
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}
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atomic.StoreInt32(&p.capacity, int32(size))
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diff := p.Running() - size
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if diff > 0 {
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for i := 0; i < diff; i++ {
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p.getWorker().task <- nil
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}
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}
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}
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// Release Closed this pool
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func (p *Pool) Release() error {
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p.once.Do(func() {
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p.release <- sig{}
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p.lock.Lock()
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idleWorkers := p.workers
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for i, w := range idleWorkers {
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<-p.freeSignal
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w.task <- nil
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idleWorkers[i] = nil
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}
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p.workers = nil
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p.lock.Unlock()
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})
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return nil
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}
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//-------------------------------------------------------------------------
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// getWorker returns a available worker to run the tasks.
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func (p *Pool) getWorker() *Worker {
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var w *Worker
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waiting := false
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p.lock.Lock()
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idleWorkers := p.workers
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n := len(idleWorkers) - 1
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if n < 0 {
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if p.Running() >= p.Cap() {
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waiting = true
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} else {
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atomic.AddInt32(&p.running, 1)
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}
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} else {
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<-p.freeSignal
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w = idleWorkers[n]
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idleWorkers[n] = nil
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p.workers = idleWorkers[:n]
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}
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p.lock.Unlock()
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if waiting {
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<-p.freeSignal
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p.lock.Lock()
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idleWorkers = p.workers
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l := len(idleWorkers) - 1
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w = idleWorkers[l]
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idleWorkers[l] = nil
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p.workers = idleWorkers[:l]
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p.lock.Unlock()
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} else if w == nil {
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w = &Worker{
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pool: p,
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task: make(chan f),
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}
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w.run()
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}
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return w
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}
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// putWorker puts a worker back into free pool, recycling the goroutines.
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func (p *Pool) putWorker(worker *Worker) {
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worker.recycleTime = time.Now()
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p.lock.Lock()
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p.workers = append(p.workers, worker)
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p.lock.Unlock()
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p.freeSignal <- sig{}
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}
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