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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2014-2022 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package progress
import (
"fmt"
"io"
"os"
"golang.org/x/crypto/ssh/terminal"
"github.com/snapcore/snapd/osutil"
)
// Meter is an interface to show progress to the user
type Meter interface {
// Start progress with max "total" steps
Start(label string, total float64)
// set progress to the "current" step
Set(current float64)
// set "total" steps needed
SetTotal(total float64)
// Finish the progress display
Finished()
// Indicate indefinite activity by showing a spinner
Spin(msg string)
// interface for writer
Write(p []byte) (n int, err error)
// notify the user of miscellaneous events
Notify(string)
}
// NullMeter is a Meter that does nothing
type NullMeter struct{}
// Null is a default NullMeter instance
var Null = NullMeter{}
func (NullMeter) Start(string, float64) {}
func (NullMeter) Set(float64) {}
func (NullMeter) SetTotal(float64) {}
func (NullMeter) Finished() {}
func (NullMeter) Write(p []byte) (int, error) { return len(p), nil }
func (NullMeter) Notify(string) {}
func (NullMeter) Spin(msg string) {}
// QuietMeter is a Meter that _just_ shows Notify()s.
type QuietMeter struct {
NullMeter
w io.Writer
}
func (m QuietMeter) Notify(msg string) {
w := m.w
if w == nil {
w = stdout
}
fmt.Fprintln(w, msg)
}
// testMeter, if set, is returned by MakeProgressBar; set it from tests.
var testMeter Meter
func MockMeter(meter Meter) func() {
testMeter = meter
return func() {
testMeter = nil
}
}
var inTesting bool = (osutil.IsTestBinary()) || os.Getenv("SPREAD_SYSTEM") != ""
var isTerminal = func() bool {
return !inTesting && terminal.IsTerminal(int(os.Stdout.Fd()))
}
// MakeProgressBar creates an appropriate progress.Meter for the environ in
// which it is called:
//
// - if MockMeter has been called, return that.
// - if w is not nil nor os.Stdout, a QuietMeter outputting to it is returned.
// - if no terminal is attached, or we think we're running a test,
// a minimalistic QuietMeter outputting to stdout is returned.
// - otherwise, an ANSIMeter is returned.
func MakeProgressBar(w io.Writer) Meter {
if testMeter != nil {
return testMeter
}
if (w == nil || w == os.Stdout) && isTerminal() {
return &ANSIMeter{}
}
return QuietMeter{w: w}
}
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