volcano.sh/volcano@v1.9.0/pkg/scheduler/util/priority_queue.go (about)

     1  /*
     2  Copyright 2017 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package util
    18  
    19  import (
    20  	"container/heap"
    21  
    22  	"volcano.sh/volcano/pkg/scheduler/api"
    23  )
    24  
    25  // PriorityQueue implements a scheduling queue.
    26  type PriorityQueue struct {
    27  	queue priorityQueue
    28  }
    29  
    30  type priorityQueue struct {
    31  	items  []interface{}
    32  	lessFn api.LessFn
    33  }
    34  
    35  // NewPriorityQueue returns a PriorityQueue
    36  func NewPriorityQueue(lessFn api.LessFn) *PriorityQueue {
    37  	return &PriorityQueue{
    38  		queue: priorityQueue{
    39  			items:  make([]interface{}, 0),
    40  			lessFn: lessFn,
    41  		},
    42  	}
    43  }
    44  
    45  // Push pushes element in the priority Queue
    46  func (q *PriorityQueue) Push(it interface{}) {
    47  	heap.Push(&q.queue, it)
    48  }
    49  
    50  // Pop pops element in the priority Queue
    51  func (q *PriorityQueue) Pop() interface{} {
    52  	if q.Len() == 0 {
    53  		return nil
    54  	}
    55  
    56  	return heap.Pop(&q.queue)
    57  }
    58  
    59  // Empty check if queue is empty
    60  func (q *PriorityQueue) Empty() bool {
    61  	return q.queue.Len() == 0
    62  }
    63  
    64  // Len returns Len of the priority queue
    65  func (q *PriorityQueue) Len() int {
    66  	return q.queue.Len()
    67  }
    68  
    69  func (pq *priorityQueue) Len() int { return len(pq.items) }
    70  
    71  func (pq *priorityQueue) Less(i, j int) bool {
    72  	if pq.lessFn == nil {
    73  		return i < j
    74  	}
    75  
    76  	// We want Pop to give us the highest, not lowest, priority so we use greater than here.
    77  	return pq.lessFn(pq.items[i], pq.items[j])
    78  }
    79  
    80  func (pq priorityQueue) Swap(i, j int) {
    81  	pq.items[i], pq.items[j] = pq.items[j], pq.items[i]
    82  }
    83  
    84  func (pq *priorityQueue) Push(x interface{}) {
    85  	(*pq).items = append((*pq).items, x)
    86  }
    87  
    88  func (pq *priorityQueue) Pop() interface{} {
    89  	old := (*pq).items
    90  	n := len(old)
    91  	item := old[n-1]
    92  	(*pq).items = old[0 : n-1]
    93  	return item
    94  }