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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:23:18 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:23:18 +0000 |
commit | 43a123c1ae6613b3efeed291fa552ecd909d3acf (patch) | |
tree | fd92518b7024bc74031f78a1cf9e454b65e73665 /misc/cgo/stdio/overlaydir_test.go | |
parent | Initial commit. (diff) | |
download | golang-1.20-43a123c1ae6613b3efeed291fa552ecd909d3acf.tar.xz golang-1.20-43a123c1ae6613b3efeed291fa552ecd909d3acf.zip |
Adding upstream version 1.20.14.upstream/1.20.14upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'misc/cgo/stdio/overlaydir_test.go')
-rw-r--r-- | misc/cgo/stdio/overlaydir_test.go | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/misc/cgo/stdio/overlaydir_test.go b/misc/cgo/stdio/overlaydir_test.go new file mode 100644 index 0000000..027ebf1 --- /dev/null +++ b/misc/cgo/stdio/overlaydir_test.go @@ -0,0 +1,78 @@ +// Copyright 2019 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package stdio_test + +import ( + "io" + "os" + "path/filepath" + "strings" +) + +// overlayDir makes a minimal-overhead copy of srcRoot in which new files may be added. +// +// TODO: Once we no longer need to support the misc module in GOPATH mode, +// factor this function out into a package to reduce duplication. +func overlayDir(dstRoot, srcRoot string) error { + dstRoot = filepath.Clean(dstRoot) + if err := os.MkdirAll(dstRoot, 0777); err != nil { + return err + } + + srcRoot, err := filepath.Abs(srcRoot) + if err != nil { + return err + } + + return filepath.Walk(srcRoot, func(srcPath string, info os.FileInfo, err error) error { + if err != nil || srcPath == srcRoot { + return err + } + + suffix := strings.TrimPrefix(srcPath, srcRoot) + for len(suffix) > 0 && suffix[0] == filepath.Separator { + suffix = suffix[1:] + } + dstPath := filepath.Join(dstRoot, suffix) + + perm := info.Mode() & os.ModePerm + if info.Mode()&os.ModeSymlink != 0 { + info, err = os.Stat(srcPath) + if err != nil { + return err + } + perm = info.Mode() & os.ModePerm + } + + // Always copy directories (don't symlink them). + // If we add a file in the overlay, we don't want to add it in the original. + if info.IsDir() { + return os.MkdirAll(dstPath, perm|0200) + } + + // If the OS supports symlinks, use them instead of copying bytes. + if err := os.Symlink(srcPath, dstPath); err == nil { + return nil + } + + // Otherwise, copy the bytes. + src, err := os.Open(srcPath) + if err != nil { + return err + } + defer src.Close() + + dst, err := os.OpenFile(dstPath, os.O_WRONLY|os.O_CREATE|os.O_EXCL, perm) + if err != nil { + return err + } + + _, err = io.Copy(dst, src) + if closeErr := dst.Close(); err == nil { + err = closeErr + } + return err + }) +} |