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https://github.com/golang/go
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476395cb3e
It turns out that the relative-path support never worked in the first place. It had been masked by the fact that we ~never invoke overlayDir with an absolute path, which caused filepath.Rel to always return an error, and overlayDir to always fall back to absolute paths. Since the absolute paths seem to be working fine (and are simpler), let's stick with those. As far as I can recall, the relative paths were only a space optimization anyway. Updates #28387 Updates #30316 Change-Id: Ie8cd28f3c41ca6497ace2799f4193d7f5dde7a37 Reviewed-on: https://go-review.googlesource.com/c/go/+/208481 Run-TryBot: Bryan C. Mills <bcmills@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Jay Conrod <jayconrod@google.com>
79 lines
1.8 KiB
Go
79 lines
1.8 KiB
Go
// Copyright 2019 The Go 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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package cgotest
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import (
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"io"
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"os"
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"path/filepath"
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"strings"
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)
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// overlayDir makes a minimal-overhead copy of srcRoot in which new files may be added.
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//
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// TODO: Once we no longer need to support the misc module in GOPATH mode,
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// factor this function out into a package to reduce duplication.
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func overlayDir(dstRoot, srcRoot string) error {
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dstRoot = filepath.Clean(dstRoot)
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if err := os.MkdirAll(dstRoot, 0777); err != nil {
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return err
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}
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srcRoot, err := filepath.Abs(srcRoot)
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if err != nil {
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return err
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}
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return filepath.Walk(srcRoot, func(srcPath string, info os.FileInfo, err error) error {
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if err != nil || srcPath == srcRoot {
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return err
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}
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suffix := strings.TrimPrefix(srcPath, srcRoot)
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for len(suffix) > 0 && suffix[0] == filepath.Separator {
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suffix = suffix[1:]
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}
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dstPath := filepath.Join(dstRoot, suffix)
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perm := info.Mode() & os.ModePerm
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if info.Mode()&os.ModeSymlink != 0 {
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info, err = os.Stat(srcPath)
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if err != nil {
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return err
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}
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perm = info.Mode() & os.ModePerm
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}
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// Always copy directories (don't symlink them).
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// If we add a file in the overlay, we don't want to add it in the original.
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if info.IsDir() {
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return os.MkdirAll(dstPath, perm|0200)
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}
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// If the OS supports symlinks, use them instead of copying bytes.
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if err := os.Symlink(srcPath, dstPath); err == nil {
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return nil
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}
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// Otherwise, copy the bytes.
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src, err := os.Open(srcPath)
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if err != nil {
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return err
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}
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defer src.Close()
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dst, err := os.OpenFile(dstPath, os.O_WRONLY|os.O_CREATE|os.O_EXCL, perm)
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if err != nil {
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return err
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}
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_, err = io.Copy(dst, src)
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if closeErr := dst.Close(); err == nil {
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err = closeErr
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}
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return err
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})
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}
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