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package fastwalk_test
import (
"fmt"
"io/fs"
"os"
"path/filepath"
"strings"
"github.com/charlievieth/fastwalk"
)
func CreateFiles(files map[string]string) (root string, cleanup func()) {
tempdir, err := os.MkdirTemp("", "fastwalk-example-*")
if err != nil {
panic(err)
}
symlinks := map[string]string{}
for path, contents := range files {
file := filepath.Join(tempdir, "/src", path)
if err := os.MkdirAll(filepath.Dir(file), 0755); err != nil {
panic(err)
}
if strings.HasPrefix(contents, "LINK:") {
symlinks[file] = filepath.FromSlash(strings.TrimPrefix(contents, "LINK:"))
continue
}
if err := os.WriteFile(file, []byte(contents), 0644); err != nil {
panic(err)
}
}
// Create symlinks after all other files. Otherwise, directory symlinks on
// Windows are unusable (see https://golang.org/issue/39183).
for file, dst := range symlinks {
if err := os.Symlink(dst, file); err != nil {
panic(err)
}
}
return filepath.Join(tempdir, "src") + "/", func() { os.RemoveAll(tempdir) }
}
func PrettyPrintEntry(root, path string, de fs.DirEntry) {
rel, err := filepath.Rel(root, path)
if err != nil {
panic(err)
}
rel = filepath.ToSlash(rel)
if de.Type()&fs.ModeSymlink != 0 {
dst, err := os.Readlink(path)
if err != nil {
panic(err)
}
fmt.Printf("%s: %s -> %s\n", de.Type(), rel, filepath.ToSlash(dst))
} else {
fmt.Printf("%s: %s\n", de.Type(), rel)
}
}
// This example shows how the [fastwalk.Config] Follow field can be used to
// efficiently and safely follow symlinks. The below example contains a symlink
// loop ("bar/symloop"), which fastwalk detects and does not follow.
//
// NOTE: We still call the [fs.WalkDirFunc] on the symlink that creates a loop,
// but we do not follow/traverse it.
func ExampleWalk_follow() {
// Setup
root, cleanup := CreateFiles(map[string]string{
"bar/bar.go": "one",
"bar/symlink": "LINK:bar.go",
"foo/foo.go": "two",
"foo/symdir": "LINK:../bar/",
"foo/broken": "LINK:nope.txt", // Broken symlink
"foo/foo": "LINK:../foo/", // Symlink loop
})
defer cleanup()
conf := fastwalk.Config{
Follow: true,
}
err := fastwalk.Walk(&conf, root, func(path string, de fs.DirEntry, err error) error {
if err != nil {
return err
}
PrettyPrintEntry(root, path, de)
return nil
})
if err != nil {
panic(err)
}
// Unordered output:
// d---------: .
// d---------: bar
// ----------: bar/bar.go
// L---------: bar/symlink -> bar.go
// d---------: foo
// L---------: foo/broken -> nope.txt
// ----------: foo/foo.go
// L---------: foo/foo -> ../foo/
// L---------: foo/symdir -> ../bar/
// L---------: foo/symdir/symlink -> bar.go
// ----------: foo/symdir/bar.go
}
func ExampleWalk() {
root, cleanup := CreateFiles(map[string]string{
"bar/b.txt": "",
"foo/f.txt": "",
// Since Config.Follow is set to false, the symbolic link "link" will
// be visited, but we will not traverse into it (since our walk func
// does not return [fastwalk.ErrTraverseLink]).
"link": "LINK:bar",
})
defer cleanup()
err := fastwalk.Walk(nil, root, func(path string, de fs.DirEntry, err error) error {
if err != nil {
return err
}
PrettyPrintEntry(root, path, de)
return nil
})
if err != nil {
panic(err)
}
// Unordered output:
// d---------: .
// d---------: bar
// d---------: foo
// L---------: link -> bar
// ----------: bar/b.txt
// ----------: foo/f.txt
}
func ExampleWalk_traverseLink() {
root, cleanup := CreateFiles(map[string]string{
"bar/b.txt": "",
"foo/f.txt": "",
// This link is followed since our walk func returns ErrTraverseLink
// when a symlink that resolves to a directory is encountered.
"link": "LINK:bar",
})
defer cleanup()
err := fastwalk.Walk(nil, root, func(path string, de fs.DirEntry, err error) error {
if err != nil {
return err
}
PrettyPrintEntry(root, path, de)
// It is strongly recommended to use fastwalk.Config.Follow instead
// of manually handling link traversal since this will fail if the
// link points to a file (and not a directory).
if de.Type()&fs.ModeSymlink != 0 {
fi, err := fastwalk.StatDirEntry(path, de)
if err != nil {
return err
}
if fi.IsDir() {
return fastwalk.ErrTraverseLink
}
}
return nil
})
if err != nil {
panic(err)
}
// Unordered output:
// d---------: .
// d---------: bar
// d---------: foo
// L---------: link -> bar
// ----------: bar/b.txt
// ----------: foo/f.txt
// ----------: link/b.txt
}
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