80 lines
1.9 KiB
Go
80 lines
1.9 KiB
Go
/*
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Copyright 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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"strconv"
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)
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const (
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// NumericalOrderAsc ascending order
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NumericalOrderAsc = "ASC"
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// NumericalOrderDesc descending order
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NumericalOrderDesc = "DESC"
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)
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// Numerical representes a Numerical ordering policy
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type Numerical struct {
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Order string
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}
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// NewNumerical constructs a Numerical object validating the provided
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// order argument
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func NewNumerical(order string) (*Numerical, error) {
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switch order {
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case "":
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order = NumericalOrderAsc
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case NumericalOrderAsc, NumericalOrderDesc:
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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, NumericalOrderAsc, NumericalOrderDesc)
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}
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return &Numerical{
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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 *Numerical) 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 latest string
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var pv float64
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for i, version := range versions {
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cv, err := strconv.ParseFloat(version, 64)
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if err != nil {
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return "", fmt.Errorf("failed to parse invalid numeric value '%s'", version)
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}
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switch {
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case i == 0:
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// First iteration, nothing to compare
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case p.Order == NumericalOrderAsc && cv < pv, p.Order == NumericalOrderDesc && cv > pv:
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continue
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}
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latest = version
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pv = cv
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}
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return latest, nil
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}
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