72 lines
1.8 KiB
Go
72 lines
1.8 KiB
Go
/*
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* Copyright (C) 2020-2022, IrineSistiana
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*
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* This file is part of mosdns.
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*
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* mosdns is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* mosdns is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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package env
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import (
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"context"
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"errors"
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"fmt"
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"github.com/IrineSistiana/mosdns/v5/pkg/query_context"
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"github.com/IrineSistiana/mosdns/v5/plugin/executable/sequence"
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"math/rand"
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"strconv"
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"sync"
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"time"
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)
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const PluginType = "random"
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func init() {
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sequence.MustRegMatchQuickSetup(PluginType, QuickSetup)
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}
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func QuickSetup(_ sequence.BQ, s string) (sequence.Matcher, error) {
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if len(s) == 0 {
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return nil, errors.New("a float64 probability is required")
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}
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p, err := strconv.ParseFloat(s, 64)
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if err != nil {
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return nil, fmt.Errorf("invalid probability, %w", err)
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}
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return Random(p), nil
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}
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type random struct {
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prob float64
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m sync.Mutex
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r *rand.Rand
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}
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func (r *random) Match(_ context.Context, _ *query_context.Context) (bool, error) {
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return r.RandBool(), nil
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}
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func (r *random) RandBool() bool {
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r.m.Lock()
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defer r.m.Unlock()
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return r.r.Float64() < r.prob
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}
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// Random returns a sequence.Matcher that returns true with a probability of prob.
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func Random(prob float64) sequence.Matcher {
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return &random{prob: prob, r: rand.New(rand.NewSource(time.Now().UnixNano()))}
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}
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