67 lines
1.7 KiB
Go
67 lines
1.7 KiB
Go
/*
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Copyright 2020, 2021 The Flux authors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package policy
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import (
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"fmt"
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"sort"
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)
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const (
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// AlphabeticalOrderAsc ascending order
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AlphabeticalOrderAsc = "ASC"
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// AlphabeticalOrderDesc descending order
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AlphabeticalOrderDesc = "DESC"
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)
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// Alphabetical representes a alphabetical ordering policy
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type Alphabetical struct {
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Order string
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}
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// NewAlphabetical constructs a Alphabetical object validating the provided
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// order argument
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func NewAlphabetical(order string) (*Alphabetical, error) {
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switch order {
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case "":
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order = AlphabeticalOrderAsc
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case AlphabeticalOrderAsc, AlphabeticalOrderDesc:
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break
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default:
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return nil, fmt.Errorf("invalid order argument provided: '%s', must be one of: %s, %s", order, AlphabeticalOrderAsc, AlphabeticalOrderDesc)
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}
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return &Alphabetical{
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Order: order,
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}, nil
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}
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// Latest returns latest version from a provided list of strings
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func (p *Alphabetical) Latest(versions []string) (string, error) {
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if len(versions) == 0 {
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return "", fmt.Errorf("version list argument cannot be empty")
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}
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var sorted sort.StringSlice = versions
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if p.Order == AlphabeticalOrderDesc {
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sort.Sort(sorted)
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} else {
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sort.Sort(sort.Reverse(sorted))
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}
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return sorted[0], nil
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}
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