/
printer.go
162 lines (136 loc) · 3.12 KB
/
printer.go
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// SPDX-FileCopyrightText: 2022 SAP SE or an SAP affiliate company and Open Component Model contributors.
//
// SPDX-License-Identifier: Apache-2.0
package common
import (
"bytes"
"fmt"
"io"
"os"
"strings"
"github.com/mandelsoft/logging"
"github.com/open-component-model/ocm/pkg/utils"
)
type Flusher interface {
Flush() error
}
func Flush(o interface{}) error {
if f, ok := o.(Flusher); ok {
return f.Flush()
}
return nil
}
var (
StdoutPrinter = NewPrinter(os.Stdout)
StderrPrinter = NewPrinter(os.Stderr)
NonePrinter = NewPrinter(nil)
)
type Printer interface {
io.Writer
Printf(msg string, args ...interface{}) (int, error)
AddGap(gap string) Printer
}
type FlushingPrinter interface {
Printer
Flusher
}
type printerState struct {
pending bool
}
type printer struct {
writer io.Writer
gap string
state *printerState
}
func NewPrinter(writer io.Writer) Printer {
return &printer{writer: writer, state: &printerState{true}}
}
func AssurePrinter(p Printer) Printer {
return utils.OptionalDefaulted(NonePrinter, p)
}
func NewBufferedPrinter() (Printer, *bytes.Buffer) {
buf := bytes.NewBuffer(nil)
return NewPrinter(buf), buf
}
func (p *printer) AddGap(gap string) Printer {
return &printer{
writer: p.writer,
gap: p.gap + gap,
state: p.state,
}
}
func (p *printer) Write(data []byte) (int, error) {
if p.writer == nil {
return 0, nil
}
s := strings.ReplaceAll(string(data), "\n", "\n"+p.gap)
if strings.HasSuffix(s, "\n"+p.gap) {
p.state.pending = true
s = s[:len(s)-len(p.gap)]
}
return p.writer.Write([]byte(s))
}
func (p *printer) printf(msg string, args ...interface{}) (int, error) {
if p == nil || p.writer == nil {
return 0, nil
}
if p.gap == "" {
return fmt.Fprintf(p.writer, msg, args...)
}
if p.state.pending {
msg = p.gap + msg
}
data := fmt.Sprintf(msg, args...)
p.state.pending = false
return p.Write([]byte(data))
}
func (p *printer) Printf(msg string, args ...interface{}) (int, error) {
return p.printf(msg, args...)
}
////////////////////////////////////////////////////////////////////////////////
type loggingPrinter struct {
log logging.Logger
gap string
pending string
}
// NewLoggingPrinter returns a printer logging the output to an
// info-level log.
// It should not be used to print binary data, but text data, only.
func NewLoggingPrinter(log logging.Logger) FlushingPrinter {
return &loggingPrinter{log: log}
}
func (p *loggingPrinter) AddGap(gap string) Printer {
return &loggingPrinter{
log: p.log,
gap: p.gap + gap,
}
}
func (p *loggingPrinter) Write(data []byte) (int, error) {
if p.log == nil {
return 0, nil
}
s := strings.Split(p.pending+string(data), "\n")
if !strings.HasSuffix(string(data), "\n") {
p.pending = s[len(s)-1]
} else {
p.pending = ""
}
s = s[:len(s)-1]
for _, l := range s {
p.log.Info(l)
}
return len(data), nil
}
func (p *loggingPrinter) Printf(msg string, args ...interface{}) (int, error) {
if p.log == nil {
return 0, nil
}
return p.Write([]byte(fmt.Sprintf(msg, args...)))
}
func (p *loggingPrinter) Flush() error {
if p.pending != "" {
p.log.Info(p.pending)
p.pending = ""
}
return nil
}