96 lines
2.5 KiB
Go
96 lines
2.5 KiB
Go
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// Package fs provides filesystem-related functions.
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package fs
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import (
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"os"
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)
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// Walker provides a convenient interface for iterating over the
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// descendants of a filesystem path.
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// Successive calls to the Step method will step through each
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// file or directory in the tree, including the root. The files
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// are walked in lexical order, which makes the output deterministic
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// but means that for very large directories Walker can be inefficient.
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// Walker does not follow symbolic links.
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type Walker struct {
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fs FileSystem
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cur item
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stack []item
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descend bool
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}
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type item struct {
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path string
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info os.FileInfo
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err error
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}
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// Walk returns a new Walker rooted at root.
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func Walk(root string) *Walker {
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return WalkFS(root, new(fs))
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}
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// WalkFS returns a new Walker rooted at root on the FileSystem fs.
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func WalkFS(root string, fs FileSystem) *Walker {
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info, err := fs.Lstat(root)
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return &Walker{
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fs: fs,
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stack: []item{{root, info, err}},
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}
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}
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// Step advances the Walker to the next file or directory,
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// which will then be available through the Path, Stat,
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// and Err methods.
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// It returns false when the walk stops at the end of the tree.
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func (w *Walker) Step() bool {
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if w.descend && w.cur.err == nil && w.cur.info.IsDir() {
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list, err := w.fs.ReadDir(w.cur.path)
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if err != nil {
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w.cur.err = err
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w.stack = append(w.stack, w.cur)
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} else {
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for i := len(list) - 1; i >= 0; i-- {
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path := w.fs.Join(w.cur.path, list[i].Name())
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w.stack = append(w.stack, item{path, list[i], nil})
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}
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}
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}
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if len(w.stack) == 0 {
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return false
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}
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i := len(w.stack) - 1
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w.cur = w.stack[i]
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w.stack = w.stack[:i]
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w.descend = true
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return true
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}
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// Path returns the path to the most recent file or directory
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// visited by a call to Step. It contains the argument to Walk
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// as a prefix; that is, if Walk is called with "dir", which is
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// a directory containing the file "a", Path will return "dir/a".
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func (w *Walker) Path() string {
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return w.cur.path
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}
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// Stat returns info for the most recent file or directory
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// visited by a call to Step.
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func (w *Walker) Stat() os.FileInfo {
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return w.cur.info
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}
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// Err returns the error, if any, for the most recent attempt
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// by Step to visit a file or directory. If a directory has
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// an error, w will not descend into that directory.
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func (w *Walker) Err() error {
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return w.cur.err
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}
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// SkipDir causes the currently visited directory to be skipped.
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// If w is not on a directory, SkipDir has no effect.
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func (w *Walker) SkipDir() {
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w.descend = false
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}
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