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46ce80758d
In prep for reducing garbage, being able to reuse memory. So far this
doesn't actually reuse much. This is just changing signatures around.
But some improvement in any case:
bradfitz@tsdev:~/src/tailscale.com$ ~/go/bin/benchstat before after
name old time/op new time/op delta
GetList-8 11.8ms ± 9% 9.9ms ± 3% -15.98% (p=0.000 n=10+10)
name old alloc/op new alloc/op delta
GetList-8 99.5kB ± 2% 91.9kB ± 0% -7.62% (p=0.000 n=9+9)
name old allocs/op new allocs/op delta
GetList-8 3.05k ± 1% 2.93k ± 0% -3.83% (p=0.000 n=8+9)
More later, once parsers can reuse strings from previous parses.
Updates #5958
Change-Id: I76cd5048246dd24d11c4e263d8bb8041747fb2b0
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
45 lines
1.1 KiB
Go
45 lines
1.1 KiB
Go
// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build (windows || freebsd || openbsd || darwin) && !ios && !js
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// +build windows freebsd openbsd darwin
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// +build !ios
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// +build !js
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package portlist
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import (
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"fmt"
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"os/exec"
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"strings"
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)
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var osHideWindow func(*exec.Cmd) // non-nil on Windows; see portlist_windows.go
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// hideWindow returns c. On Windows it first sets SysProcAttr.HideWindow.
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func hideWindow(c *exec.Cmd) *exec.Cmd {
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if osHideWindow != nil {
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osHideWindow(c)
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}
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return c
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}
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func appendListeningPortsNetstat(base []Port, arg string) ([]Port, error) {
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exe, err := exec.LookPath("netstat")
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if err != nil {
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return nil, fmt.Errorf("netstat: lookup: %v", err)
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}
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output, err := hideWindow(exec.Command(exe, arg)).Output()
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if err != nil {
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xe, ok := err.(*exec.ExitError)
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stderr := ""
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if ok {
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stderr = strings.TrimSpace(string(xe.Stderr))
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}
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return nil, fmt.Errorf("netstat: %v (%q)", err, stderr)
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}
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return appendParsePortsNetstat(base, string(output)), nil
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}
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