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Bel LaPointe
2020-09-06 09:37:44 -06:00
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202
vendor/github.com/golang-collections/go-datastructures/LICENSE generated vendored Normal file
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Apache License
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vendor/github.com/golang-collections/go-datastructures/queue/error.go generated vendored Normal file
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/*
Copyright 2014 Workiva, LLC
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 queue
import "errors"
var disposedError = errors.New(`Queue has been disposed.`)

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vendor/github.com/golang-collections/go-datastructures/queue/priority_queue.go generated vendored Normal file
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/*
Copyright 2014 Workiva, LLC
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.
*/
/*
The priority queue is almost a spitting image of the logic
used for a regular queue. In order to keep the logic fast,
this code is repeated instead of using casts to cast to interface{}
back and forth. If Go had inheritance and generics, this problem
would be easier to solve.
*/
package queue
import (
"sort"
"sync"
)
// Item is an item that can be added to the priority queue.
type Item interface {
// Compare returns a bool that can be used to determine
// ordering in the priority queue. Assuming the queue
// is in ascending order, this should return > logic.
// Return 1 to indicate this object is greater than the
// the other logic, 0 to indicate equality, and -1 to indicate
// less than other.
Compare(other Item) int
}
type priorityItems []Item
func (items *priorityItems) get(number int) []Item {
returnItems := make([]Item, 0, number)
index := 0
for i := 0; i < number; i++ {
if i >= len(*items) {
break
}
returnItems = append(returnItems, (*items)[i])
(*items)[i] = nil
index++
}
*items = (*items)[index:]
return returnItems
}
func (items *priorityItems) insert(item Item) {
if len(*items) == 0 {
*items = append(*items, item)
return
}
equalFound := false
i := sort.Search(len(*items), func(i int) bool {
result := (*items)[i].Compare(item)
if result == 0 {
equalFound = true
}
return result >= 0
})
if equalFound {
return
}
if i == len(*items) {
*items = append(*items, item)
return
}
*items = append(*items, nil)
copy((*items)[i+1:], (*items)[i:])
(*items)[i] = item
}
// PriorityQueue is similar to queue except that it takes
// items that implement the Item interface and adds them
// to the queue in priority order.
type PriorityQueue struct {
waiters waiters
items priorityItems
lock sync.Mutex
disposeLock sync.Mutex
disposed bool
}
// Put adds items to the queue.
func (pq *PriorityQueue) Put(items ...Item) error {
if len(items) == 0 {
return nil
}
pq.lock.Lock()
if pq.disposed {
pq.lock.Unlock()
return disposedError
}
for _, item := range items {
pq.items.insert(item)
}
for {
sema := pq.waiters.get()
if sema == nil {
break
}
sema.response.Add(1)
sema.wg.Done()
sema.response.Wait()
if len(pq.items) == 0 {
break
}
}
pq.lock.Unlock()
return nil
}
// Get retrieves items from the queue. If the queue is empty,
// this call blocks until the next item is added to the queue. This
// will attempt to retrieve number of items.
func (pq *PriorityQueue) Get(number int) ([]Item, error) {
if number < 1 {
return nil, nil
}
pq.lock.Lock()
if pq.disposed {
pq.lock.Unlock()
return nil, disposedError
}
var items []Item
if len(pq.items) == 0 {
sema := newSema()
pq.waiters.put(sema)
sema.wg.Add(1)
pq.lock.Unlock()
sema.wg.Wait()
pq.disposeLock.Lock()
if pq.disposed {
pq.disposeLock.Unlock()
return nil, disposedError
}
pq.disposeLock.Unlock()
items = pq.items.get(number)
sema.response.Done()
return items, nil
}
items = pq.items.get(number)
pq.lock.Unlock()
return items, nil
}
// Peek will look at the next item without removing it from the queue.
func (pq *PriorityQueue) Peek() Item {
pq.lock.Lock()
defer pq.lock.Unlock()
if len(pq.items) > 0 {
return pq.items[0]
}
return nil
}
// Empty returns a bool indicating if there are any items left
// in the queue.
func (pq *PriorityQueue) Empty() bool {
pq.lock.Lock()
defer pq.lock.Unlock()
return len(pq.items) == 0
}
// Len returns a number indicating how many items are in the queue.
func (pq *PriorityQueue) Len() int {
pq.lock.Lock()
defer pq.lock.Unlock()
return len(pq.items)
}
// Disposed returns a bool indicating if this queue has been disposed.
func (pq *PriorityQueue) Disposed() bool {
pq.lock.Lock()
defer pq.lock.Unlock()
return pq.disposed
}
// Dispose will prevent any further reads/writes to this queue
// and frees available resources.
func (pq *PriorityQueue) Dispose() {
pq.lock.Lock()
defer pq.lock.Unlock()
pq.disposeLock.Lock()
defer pq.disposeLock.Unlock()
pq.disposed = true
for _, waiter := range pq.waiters {
waiter.response.Add(1)
waiter.wg.Done()
}
pq.items = nil
pq.waiters = nil
}
// NewPriorityQueue is the constructor for a priority queue.
func NewPriorityQueue(hint int) *PriorityQueue {
return &PriorityQueue{
items: make(priorityItems, 0, hint),
}
}

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vendor/github.com/golang-collections/go-datastructures/queue/queue.go generated vendored Normal file
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/*
Copyright 2014 Workiva, LLC
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 queue includes a regular queue and a priority queue.
These queues rely on waitgroups to pause listening threads
on empty queues until a message is received. If any thread
calls Dispose on the queue, any listeners are immediately returned
with an error. Any subsequent put to the queue will return an error
as opposed to panicking as with channels. Queues will grow with unbounded
behavior as opposed to channels which can be buffered but will pause
while a thread attempts to put to a full channel.
Recently added is a lockless ring buffer using the same basic C design as
found here:
http://www.1024cores.net/home/lock-free-algorithms/queues/bounded-mpmc-queue
Modified for use with Go with the addition of some dispose semantics providing
the capability to release blocked threads. This works for both puts
and gets, either will return an error if they are blocked and the buffer
is disposed. This could serve as a signal to kill a goroutine. All threadsafety
is acheived using CAS operations, making this buffer pretty quick.
Benchmarks:
BenchmarkPriorityQueue-8 2000000 782 ns/op
BenchmarkQueue-8 2000000 671 ns/op
BenchmarkChannel-8 1000000 2083 ns/op
BenchmarkQueuePut-8 20000 84299 ns/op
BenchmarkQueueGet-8 20000 80753 ns/op
BenchmarkExecuteInParallel-8 20000 68891 ns/op
BenchmarkRBLifeCycle-8 10000000 177 ns/op
BenchmarkRBPut-8 30000000 58.1 ns/op
BenchmarkRBGet-8 50000000 26.8 ns/op
TODO: We really need a Fibonacci heap for the priority queue.
TODO: Unify the types of queue to the same interface.
*/
package queue
import (
"runtime"
"sync"
"sync/atomic"
)
type waiters []*sema
func (w *waiters) get() *sema {
if len(*w) == 0 {
return nil
}
sema := (*w)[0]
copy((*w)[0:], (*w)[1:])
(*w)[len(*w)-1] = nil // or the zero value of T
*w = (*w)[:len(*w)-1]
return sema
}
func (w *waiters) put(sema *sema) {
*w = append(*w, sema)
}
type items []interface{}
func (items *items) get(number int64) []interface{} {
returnItems := make([]interface{}, 0, number)
index := int64(0)
for i := int64(0); i < number; i++ {
if i >= int64(len(*items)) {
break
}
returnItems = append(returnItems, (*items)[i])
(*items)[i] = nil
index++
}
*items = (*items)[index:]
return returnItems
}
func (items *items) getUntil(checker func(item interface{}) bool) []interface{} {
length := len(*items)
if len(*items) == 0 {
// returning nil here actually wraps that nil in a list
// of interfaces... thanks go
return []interface{}{}
}
returnItems := make([]interface{}, 0, length)
index := 0
for i, item := range *items {
if !checker(item) {
break
}
returnItems = append(returnItems, item)
index = i
}
*items = (*items)[index:]
return returnItems
}
type sema struct {
wg *sync.WaitGroup
response *sync.WaitGroup
}
func newSema() *sema {
return &sema{
wg: &sync.WaitGroup{},
response: &sync.WaitGroup{},
}
}
// Queue is the struct responsible for tracking the state
// of the queue.
type Queue struct {
waiters waiters
items items
lock sync.Mutex
disposed bool
}
// Put will add the specified items to the queue.
func (q *Queue) Put(items ...interface{}) error {
if len(items) == 0 {
return nil
}
q.lock.Lock()
if q.disposed {
q.lock.Unlock()
return disposedError
}
q.items = append(q.items, items...)
for {
sema := q.waiters.get()
if sema == nil {
break
}
sema.response.Add(1)
sema.wg.Done()
sema.response.Wait()
if len(q.items) == 0 {
break
}
}
q.lock.Unlock()
return nil
}
// Get will add an item to the queue. If there are some items in the
// queue, get will return a number UP TO the number passed in as a
// parameter. If no items are in the queue, this method will pause
// until items are added to the queue.
func (q *Queue) Get(number int64) ([]interface{}, error) {
if number < 1 {
// thanks again go
return []interface{}{}, nil
}
q.lock.Lock()
if q.disposed {
q.lock.Unlock()
return nil, disposedError
}
var items []interface{}
if len(q.items) == 0 {
sema := newSema()
q.waiters.put(sema)
sema.wg.Add(1)
q.lock.Unlock()
sema.wg.Wait()
// we are now inside the put's lock
if q.disposed {
return nil, disposedError
}
items = q.items.get(number)
sema.response.Done()
return items, nil
}
items = q.items.get(number)
q.lock.Unlock()
return items, nil
}
// TakeUntil takes a function and returns a list of items that
// match the checker until the checker returns false. This does not
// wait if there are no items in the queue.
func (q *Queue) TakeUntil(checker func(item interface{}) bool) ([]interface{}, error) {
if checker == nil {
return nil, nil
}
q.lock.Lock()
if q.disposed {
q.lock.Unlock()
return nil, disposedError
}
result := q.items.getUntil(checker)
q.lock.Unlock()
return result, nil
}
// Empty returns a bool indicating if this bool is empty.
func (q *Queue) Empty() bool {
q.lock.Lock()
defer q.lock.Unlock()
return len(q.items) == 0
}
// Len returns the number of items in this queue.
func (q *Queue) Len() int64 {
q.lock.Lock()
defer q.lock.Unlock()
return int64(len(q.items))
}
// Disposed returns a bool indicating if this queue
// has had disposed called on it.
func (q *Queue) Disposed() bool {
q.lock.Lock()
defer q.lock.Unlock()
return q.disposed
}
// Dispose will dispose of this queue. Any subsequent
// calls to Get or Put will return an error.
func (q *Queue) Dispose() {
q.lock.Lock()
defer q.lock.Unlock()
q.disposed = true
for _, waiter := range q.waiters {
waiter.response.Add(1)
waiter.wg.Done()
}
q.items = nil
q.waiters = nil
}
// New is a constructor for a new threadsafe queue.
func New(hint int64) *Queue {
return &Queue{
items: make([]interface{}, 0, hint),
}
}
// ExecuteInParallel will (in parallel) call the provided function
// with each item in the queue until the queue is exhausted. When the queue
// is exhausted execution is complete and all goroutines will be killed.
// This means that the queue will be disposed so cannot be used again.
func ExecuteInParallel(q *Queue, fn func(interface{})) {
if q == nil {
return
}
q.lock.Lock() // so no one touches anything in the middle
// of this process
todo, done := uint64(len(q.items)), int64(-1)
// this is important or we might face an infinite loop
if todo == 0 {
return
}
numCPU := 1
if runtime.NumCPU() > 1 {
numCPU = runtime.NumCPU() - 1
}
var wg sync.WaitGroup
wg.Add(numCPU)
items := q.items
for i := 0; i < numCPU; i++ {
go func() {
for {
index := atomic.AddInt64(&done, 1)
if index >= int64(todo) {
wg.Done()
break
}
fn(items[index])
items[index] = 0
}
}()
}
wg.Wait()
q.lock.Unlock()
q.Dispose()
}

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vendor/github.com/golang-collections/go-datastructures/queue/ring.go generated vendored Normal file
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/*
Copyright 2014 Workiva, LLC
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 queue
import (
"runtime"
"sync/atomic"
)
// roundUp takes a uint64 greater than 0 and rounds it up to the next
// power of 2.
func roundUp(v uint64) uint64 {
v--
v |= v >> 1
v |= v >> 2
v |= v >> 4
v |= v >> 8
v |= v >> 16
v |= v >> 32
v++
return v
}
type node struct {
position uint64
data interface{}
}
type nodes []*node
// RingBuffer is a MPMC buffer that achieves threadsafety with CAS operations
// only. A put on full or get on empty call will block until an item
// is put or retrieved. Calling Dispose on the RingBuffer will unblock
// any blocked threads with an error. This buffer is similar to the buffer
// described here: http://www.1024cores.net/home/lock-free-algorithms/queues/bounded-mpmc-queue
// with some minor additions.
type RingBuffer struct {
nodes nodes
queue, dequeue, mask, disposed uint64
}
func (rb *RingBuffer) init(size uint64) {
size = roundUp(size)
rb.nodes = make(nodes, size)
for i := uint64(0); i < size; i++ {
rb.nodes[i] = &node{position: i}
}
rb.mask = size - 1 // so we don't have to do this with every put/get operation
}
// Put adds the provided item to the queue. If the queue is full, this
// call will block until an item is added to the queue or Dispose is called
// on the queue. An error will be returned if the queue is disposed.
func (rb *RingBuffer) Put(item interface{}) error {
var n *node
pos := atomic.LoadUint64(&rb.queue)
L:
for {
if atomic.LoadUint64(&rb.disposed) == 1 {
return disposedError
}
n = rb.nodes[pos&rb.mask]
seq := atomic.LoadUint64(&n.position)
switch dif := seq - pos; {
case dif == 0:
if atomic.CompareAndSwapUint64(&rb.queue, pos, pos+1) {
break L
}
case dif < 0:
panic(`Ring buffer in a compromised state during a put operation.`)
default:
pos = atomic.LoadUint64(&rb.queue)
}
runtime.Gosched() // free up the cpu before the next iteration
}
n.data = item
atomic.StoreUint64(&n.position, pos+1)
return nil
}
// Get will return the next item in the queue. This call will block
// if the queue is empty. This call will unblock when an item is added
// to the queue or Dispose is called on the queue. An error will be returned
// if the queue is disposed.
func (rb *RingBuffer) Get() (interface{}, error) {
var n *node
pos := atomic.LoadUint64(&rb.dequeue)
L:
for {
if atomic.LoadUint64(&rb.disposed) == 1 {
return nil, disposedError
}
n = rb.nodes[pos&rb.mask]
seq := atomic.LoadUint64(&n.position)
switch dif := seq - (pos + 1); {
case dif == 0:
if atomic.CompareAndSwapUint64(&rb.dequeue, pos, pos+1) {
break L
}
case dif < 0:
panic(`Ring buffer in compromised state during a get operation.`)
default:
pos = atomic.LoadUint64(&rb.dequeue)
}
runtime.Gosched() // free up cpu before next iteration
}
data := n.data
n.data = nil
atomic.StoreUint64(&n.position, pos+rb.mask+1)
return data, nil
}
// Len returns the number of items in the queue.
func (rb *RingBuffer) Len() uint64 {
return atomic.LoadUint64(&rb.queue) - atomic.LoadUint64(&rb.dequeue)
}
// Cap returns the capacity of this ring buffer.
func (rb *RingBuffer) Cap() uint64 {
return uint64(len(rb.nodes))
}
// Dispose will dispose of this queue and free any blocked threads
// in the Put and/or Get methods. Calling those methods on a disposed
// queue will return an error.
func (rb *RingBuffer) Dispose() {
atomic.CompareAndSwapUint64(&rb.disposed, 0, 1)
}
// IsDisposed will return a bool indicating if this queue has been
// disposed.
func (rb *RingBuffer) IsDisposed() bool {
return atomic.LoadUint64(&rb.disposed) == 1
}
// NewRingBuffer will allocate, initialize, and return a ring buffer
// with the specified size.
func NewRingBuffer(size uint64) *RingBuffer {
rb := &RingBuffer{}
rb.init(size)
return rb
}