85 lines
2.0 KiB
Go
85 lines
2.0 KiB
Go
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// Copyright 2019 Sorint.lab
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package common
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import (
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"io"
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"io/ioutil"
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"os"
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"path/filepath"
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"strings"
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)
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// WriteFileAtomicFunc atomically writes a file, it achieves this by creating a
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// temporary file and then moving it. writeFunc is the func that will write
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// data to the file.
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// TODO(sgotti) remove left over tmp files if process crashes before calling
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// os.Remove
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func WriteFileAtomicFunc(p, baseDir, tmpDir string, perm os.FileMode, persist bool, writeFunc func(f io.Writer) error) error {
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f, err := ioutil.TempFile(tmpDir, "tmpfile")
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if err != nil {
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return err
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}
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err = writeFunc(f)
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if persist && err == nil {
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err = f.Sync()
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}
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if closeErr := f.Close(); err == nil {
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err = closeErr
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}
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if permErr := os.Chmod(f.Name(), perm); err == nil {
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err = permErr
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}
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if err == nil {
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err = os.Rename(f.Name(), p)
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}
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if err != nil {
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os.Remove(f.Name())
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return err
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}
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if !persist {
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return nil
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}
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// sync parent dirs
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pdir := filepath.Dir(p)
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for {
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if !strings.HasPrefix(pdir, baseDir) {
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break
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}
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f, err := os.Open(pdir)
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if err != nil {
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f.Close()
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return nil
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}
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if err := f.Sync(); err != nil {
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f.Close()
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return nil
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}
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f.Close()
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pdir = filepath.Dir(pdir)
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}
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return nil
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}
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func WriteFileAtomic(filename, baseDir, tmpDir string, perm os.FileMode, persist bool, data []byte) error {
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return WriteFileAtomicFunc(filename, baseDir, tmpDir, perm, persist,
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func(f io.Writer) error {
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_, err := f.Write(data)
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return err
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})
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}
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