/
sorter.go
128 lines (116 loc) · 3.27 KB
/
sorter.go
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/*
* Copyright (c) 2018 Samsung Electronics Co., Ltd All Rights Reserved
*
* 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
*/
// File workers/sorter.go provides implementation of boruta.Sorter interface.
package workers
import (
"strings"
"github.com/SamsungSLAV/boruta"
)
// sorter implements sort.Interface. It allows to sort by worker UUID (default), State or
// Groups in ascending or descending order. It is used by ListWorkers.
type sorter struct {
list []boruta.WorkerInfo
item string
order boruta.SortOrder
}
// newSorter returns sorter initialized with SortInfo data. It may return an error when info is nil
// or it contains unknown item.
func newSorter(info *boruta.SortInfo) (*sorter, error) {
if info == nil {
return &sorter{
order: boruta.SortOrderAsc,
item: "uuid",
}, nil
}
item := strings.ToLower(info.Item)
switch item {
case "":
case "uuid":
case "state":
case "groups":
default:
return nil, boruta.ErrWrongSortItem
}
return &sorter{
order: info.Order,
item: item,
}, nil
}
// Len returns length of underlying WorkerInfo slice. It is part of sort.Interface.
func (sorter *sorter) Len() int {
return len(sorter.list)
}
// Swap swaps the elements of underlying WorkerInfo slice. It is part of sort.Interface.
func (sorter *sorter) Swap(i, j int) {
sorter.list[i], sorter.list[j] = sorter.list[j], sorter.list[i]
}
// Less reports if element with index i in underlying WorkerInfo slice should be before the element
// with index j. It may panic when item wasn't set or was set to wrong value. It is part of
// sort.Interface.
func (sorter *sorter) Less(i, j int) bool {
var less func(a, b int) bool
applySortOrder := func(retval bool) bool {
if sorter.order == boruta.SortOrderAsc {
return retval
}
return !retval
}
lessUUID := func(a, b int) bool {
return applySortOrder(sorter.list[a].WorkerUUID < sorter.list[b].WorkerUUID)
}
switch sorter.item {
case "":
// UUID is the default sort item.
fallthrough
case "uuid":
less = lessUUID
case "state":
less = func(a, b int) bool {
if sorter.list[a].State == sorter.list[b].State {
return lessUUID(a, b)
}
return applySortOrder(sorter.list[a].State < sorter.list[b].State)
}
case "groups":
less = func(a, b int) bool {
var min int
ga := sorter.list[a].Groups
gb := sorter.list[b].Groups
la := len(ga)
lb := len(gb)
if la <= lb {
min = la
} else {
min = lb
}
for i := 0; i < min; i++ {
if ga[i] < gb[i] {
return applySortOrder(true)
} else if ga[i] > gb[i] {
return applySortOrder(false)
}
}
// Up to min groups are equal.
if la == lb {
return lessUUID(a, b)
}
return applySortOrder(la < lb)
}
default:
panic(sorter.item + ": " + boruta.ErrWrongSortItem.Error())
}
return less(i, j)
}