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Diffstat (limited to 'vendor/k8s.io/client-go/tools/cache/heap.go')
-rw-r--r-- | vendor/k8s.io/client-go/tools/cache/heap.go | 323 |
1 files changed, 0 insertions, 323 deletions
diff --git a/vendor/k8s.io/client-go/tools/cache/heap.go b/vendor/k8s.io/client-go/tools/cache/heap.go deleted file mode 100644 index 78e492455..000000000 --- a/vendor/k8s.io/client-go/tools/cache/heap.go +++ /dev/null @@ -1,323 +0,0 @@ -/* -Copyright 2017 The Kubernetes Authors. - -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. -*/ - -// This file implements a heap data structure. - -package cache - -import ( - "container/heap" - "fmt" - "sync" -) - -const ( - closedMsg = "heap is closed" -) - -type LessFunc func(interface{}, interface{}) bool -type heapItem struct { - obj interface{} // The object which is stored in the heap. - index int // The index of the object's key in the Heap.queue. -} - -type itemKeyValue struct { - key string - obj interface{} -} - -// heapData is an internal struct that implements the standard heap interface -// and keeps the data stored in the heap. -type heapData struct { - // items is a map from key of the objects to the objects and their index. - // We depend on the property that items in the map are in the queue and vice versa. - items map[string]*heapItem - // queue implements a heap data structure and keeps the order of elements - // according to the heap invariant. The queue keeps the keys of objects stored - // in "items". - queue []string - - // keyFunc is used to make the key used for queued item insertion and retrieval, and - // should be deterministic. - keyFunc KeyFunc - // lessFunc is used to compare two objects in the heap. - lessFunc LessFunc -} - -var ( - _ = heap.Interface(&heapData{}) // heapData is a standard heap -) - -// Less compares two objects and returns true if the first one should go -// in front of the second one in the heap. -func (h *heapData) Less(i, j int) bool { - if i > len(h.queue) || j > len(h.queue) { - return false - } - itemi, ok := h.items[h.queue[i]] - if !ok { - return false - } - itemj, ok := h.items[h.queue[j]] - if !ok { - return false - } - return h.lessFunc(itemi.obj, itemj.obj) -} - -// Len returns the number of items in the Heap. -func (h *heapData) Len() int { return len(h.queue) } - -// Swap implements swapping of two elements in the heap. This is a part of standard -// heap interface and should never be called directly. -func (h *heapData) Swap(i, j int) { - h.queue[i], h.queue[j] = h.queue[j], h.queue[i] - item := h.items[h.queue[i]] - item.index = i - item = h.items[h.queue[j]] - item.index = j -} - -// Push is supposed to be called by heap.Push only. -func (h *heapData) Push(kv interface{}) { - keyValue := kv.(*itemKeyValue) - n := len(h.queue) - h.items[keyValue.key] = &heapItem{keyValue.obj, n} - h.queue = append(h.queue, keyValue.key) -} - -// Pop is supposed to be called by heap.Pop only. -func (h *heapData) Pop() interface{} { - key := h.queue[len(h.queue)-1] - h.queue = h.queue[0 : len(h.queue)-1] - item, ok := h.items[key] - if !ok { - // This is an error - return nil - } - delete(h.items, key) - return item.obj -} - -// Heap is a thread-safe producer/consumer queue that implements a heap data structure. -// It can be used to implement priority queues and similar data structures. -type Heap struct { - lock sync.RWMutex - cond sync.Cond - - // data stores objects and has a queue that keeps their ordering according - // to the heap invariant. - data *heapData - - // closed indicates that the queue is closed. - // It is mainly used to let Pop() exit its control loop while waiting for an item. - closed bool -} - -// Close the Heap and signals condition variables that may be waiting to pop -// items from the heap. -func (h *Heap) Close() { - h.lock.Lock() - defer h.lock.Unlock() - h.closed = true - h.cond.Broadcast() -} - -// Add inserts an item, and puts it in the queue. The item is updated if it -// already exists. -func (h *Heap) Add(obj interface{}) error { - key, err := h.data.keyFunc(obj) - if err != nil { - return KeyError{obj, err} - } - h.lock.Lock() - defer h.lock.Unlock() - if h.closed { - return fmt.Errorf(closedMsg) - } - if _, exists := h.data.items[key]; exists { - h.data.items[key].obj = obj - heap.Fix(h.data, h.data.items[key].index) - } else { - h.addIfNotPresentLocked(key, obj) - } - h.cond.Broadcast() - return nil -} - -// Adds all the items in the list to the queue and then signals the condition -// variable. It is useful when the caller would like to add all of the items -// to the queue before consumer starts processing them. -func (h *Heap) BulkAdd(list []interface{}) error { - h.lock.Lock() - defer h.lock.Unlock() - if h.closed { - return fmt.Errorf(closedMsg) - } - for _, obj := range list { - key, err := h.data.keyFunc(obj) - if err != nil { - return KeyError{obj, err} - } - if _, exists := h.data.items[key]; exists { - h.data.items[key].obj = obj - heap.Fix(h.data, h.data.items[key].index) - } else { - h.addIfNotPresentLocked(key, obj) - } - } - h.cond.Broadcast() - return nil -} - -// AddIfNotPresent inserts an item, and puts it in the queue. If an item with -// the key is present in the map, no changes is made to the item. -// -// This is useful in a single producer/consumer scenario so that the consumer can -// safely retry items without contending with the producer and potentially enqueueing -// stale items. -func (h *Heap) AddIfNotPresent(obj interface{}) error { - id, err := h.data.keyFunc(obj) - if err != nil { - return KeyError{obj, err} - } - h.lock.Lock() - defer h.lock.Unlock() - if h.closed { - return fmt.Errorf(closedMsg) - } - h.addIfNotPresentLocked(id, obj) - h.cond.Broadcast() - return nil -} - -// addIfNotPresentLocked assumes the lock is already held and adds the the provided -// item to the queue if it does not already exist. -func (h *Heap) addIfNotPresentLocked(key string, obj interface{}) { - if _, exists := h.data.items[key]; exists { - return - } - heap.Push(h.data, &itemKeyValue{key, obj}) -} - -// Update is the same as Add in this implementation. When the item does not -// exist, it is added. -func (h *Heap) Update(obj interface{}) error { - return h.Add(obj) -} - -// Delete removes an item. -func (h *Heap) Delete(obj interface{}) error { - key, err := h.data.keyFunc(obj) - if err != nil { - return KeyError{obj, err} - } - h.lock.Lock() - defer h.lock.Unlock() - if item, ok := h.data.items[key]; ok { - heap.Remove(h.data, item.index) - return nil - } - return fmt.Errorf("object not found") -} - -// Pop waits until an item is ready. If multiple items are -// ready, they are returned in the order given by Heap.data.lessFunc. -func (h *Heap) Pop() (interface{}, error) { - h.lock.Lock() - defer h.lock.Unlock() - for len(h.data.queue) == 0 { - // When the queue is empty, invocation of Pop() is blocked until new item is enqueued. - // When Close() is called, the h.closed is set and the condition is broadcast, - // which causes this loop to continue and return from the Pop(). - if h.closed { - return nil, fmt.Errorf("heap is closed") - } - h.cond.Wait() - } - obj := heap.Pop(h.data) - if obj != nil { - return obj, nil - } else { - return nil, fmt.Errorf("object was removed from heap data") - } -} - -// List returns a list of all the items. -func (h *Heap) List() []interface{} { - h.lock.RLock() - defer h.lock.RUnlock() - list := make([]interface{}, 0, len(h.data.items)) - for _, item := range h.data.items { - list = append(list, item.obj) - } - return list -} - -// ListKeys returns a list of all the keys of the objects currently in the Heap. -func (h *Heap) ListKeys() []string { - h.lock.RLock() - defer h.lock.RUnlock() - list := make([]string, 0, len(h.data.items)) - for key := range h.data.items { - list = append(list, key) - } - return list -} - -// Get returns the requested item, or sets exists=false. -func (h *Heap) Get(obj interface{}) (interface{}, bool, error) { - key, err := h.data.keyFunc(obj) - if err != nil { - return nil, false, KeyError{obj, err} - } - return h.GetByKey(key) -} - -// GetByKey returns the requested item, or sets exists=false. -func (h *Heap) GetByKey(key string) (interface{}, bool, error) { - h.lock.RLock() - defer h.lock.RUnlock() - item, exists := h.data.items[key] - if !exists { - return nil, false, nil - } - return item.obj, true, nil -} - -// IsClosed returns true if the queue is closed. -func (h *Heap) IsClosed() bool { - h.lock.RLock() - defer h.lock.RUnlock() - if h.closed { - return true - } - return false -} - -// NewHeap returns a Heap which can be used to queue up items to process. -func NewHeap(keyFn KeyFunc, lessFn LessFunc) *Heap { - h := &Heap{ - data: &heapData{ - items: map[string]*heapItem{}, - queue: []string{}, - keyFunc: keyFn, - lessFunc: lessFn, - }, - } - h.cond.L = &h.lock - return h -} |