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package builder
import (
"compress/gzip"
"io"
"os"
"github.com/andybalholm/brotli"
)
const (
gzipLevel = 6
brotliLevel = 9
)
type MultiWriteCloser struct {
writers []io.WriteCloser
multiWriter io.Writer
}
func (mw *MultiWriteCloser) Write(p []byte) (n int, err error) {
return mw.multiWriter.Write(p)
}
func (mw *MultiWriteCloser) Close() error {
var lastErr error
for _, w := range mw.writers {
err := w.Close()
if err != nil {
lastErr = err
}
}
return lastErr
}
func openFileWrite(filename string) (*os.File, error) {
return os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
}
func openFileGz(filename string) (*gzip.Writer, error) {
filenameGz := filename + ".gz"
f, err := openFileWrite(filenameGz)
if err != nil {
return nil, err
}
return gzip.NewWriterLevel(f, gzipLevel)
}
func openFileBrotli(filename string) (*brotli.Writer, error) {
filenameBrotli := filename + ".br"
f, err := openFileWrite(filenameBrotli)
if err != nil {
return nil, err
}
return brotli.NewWriterLevel(f, brotliLevel), nil
}
func multiOpenFile(filename string) (*MultiWriteCloser, error) {
r, err := openFileWrite(filename)
if err != nil {
return nil, err
}
gz, err := openFileGz(filename)
if err != nil {
return nil, err
}
br, err := openFileBrotli(filename)
if err != nil {
return nil, err
}
return &MultiWriteCloser{
writers: []io.WriteCloser{r, gz, br},
multiWriter: io.MultiWriter(r, gz, br),
}, nil
}
func openFileAndVariants(filename string) (io.WriteCloser, error) {
if compressFiles {
return multiOpenFile(filename)
} else {
return openFileWrite(filename)
}
}
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