82 lines
1.4 KiB
Go
82 lines
1.4 KiB
Go
// Copyright (C) 2014 Jakob Borg and Contributors (see the CONTRIBUTORS file).
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// All rights reserved. Use of this source code is governed by an MIT-style
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// license that can be found in the LICENSE file.
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package model
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import (
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"os"
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"sync"
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"time"
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)
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const (
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MaxChangeHistory = 4
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)
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type change struct {
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size int64
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when time.Time
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}
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type changeHistory struct {
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changes []change
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next int64
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prevSup bool
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}
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type suppressor struct {
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sync.Mutex
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changes map[string]changeHistory
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threshold int64 // bytes/s
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}
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func (h changeHistory) bandwidth(t time.Time) int64 {
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if len(h.changes) == 0 {
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return 0
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}
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var t0 = h.changes[0].when
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if t == t0 {
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return 0
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}
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var bw float64
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for _, c := range h.changes {
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bw += float64(c.size)
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}
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return int64(bw / t.Sub(t0).Seconds())
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}
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func (h *changeHistory) append(size int64, t time.Time) {
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c := change{size, t}
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if len(h.changes) == MaxChangeHistory {
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h.changes = h.changes[1:MaxChangeHistory]
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}
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h.changes = append(h.changes, c)
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}
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func (s *suppressor) Suppress(name string, fi os.FileInfo) (cur, prev bool) {
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return s.suppress(name, fi.Size(), time.Now())
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}
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func (s *suppressor) suppress(name string, size int64, t time.Time) (bool, bool) {
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s.Lock()
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if s.changes == nil {
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s.changes = make(map[string]changeHistory)
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}
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h := s.changes[name]
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sup := h.bandwidth(t) > s.threshold
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prevSup := h.prevSup
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h.prevSup = sup
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if !sup {
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h.append(size, t)
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}
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s.changes[name] = h
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s.Unlock()
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return sup, prevSup
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}
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