67 lines
1.6 KiB
Go
67 lines
1.6 KiB
Go
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package discovery
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import (
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"os"
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"strings"
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)
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// PrefixTree narrows a Tree to the subtree below Prefix; paths passed in and
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// reported back are relative to that subtree.
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type PrefixTree struct {
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Tree Tree
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Prefix string
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}
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func (p *PrefixTree) Walk(fn func(rel string, isDir bool) error) error {
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prefix := strings.TrimSuffix(p.Prefix, "/") + "/"
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return p.Tree.Walk(func(rel string, isDir bool) error {
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if rel == p.Prefix || strings.HasPrefix(rel, prefix) {
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sub := strings.TrimPrefix(rel, prefix)
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if sub == "" {
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return nil
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}
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return fn(sub, isDir)
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}
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return nil
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})
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}
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func (p *PrefixTree) ReadFile(rel string) ([]byte, error) {
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return p.Tree.ReadFile(p.Prefix + "/" + rel)
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}
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// FilesUnder delegates to the underlying tree with the prefix reapplied.
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func (p *PrefixTree) FilesUnder(prefix string) ([]string, error) {
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lister, ok := p.Tree.(interface {
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FilesUnder(prefix string) ([]string, error)
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})
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if !ok {
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return nil, os.ErrNotExist
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}
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full := prefix
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if p.Prefix != "" {
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full = p.Prefix + "/" + strings.TrimSuffix(prefix, "/")
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}
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files, err := lister.FilesUnder(full)
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if err != nil {
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return nil, err
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}
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trim := p.Prefix + "/"
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out := make([]string, 0, len(files))
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for _, f := range files {
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out = append(out, strings.TrimPrefix(f, trim))
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}
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return out, nil
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}
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// MaterializeFile delegates to the underlying tree with the prefix reapplied.
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func (p *PrefixTree) MaterializeFile(rel, dst string) error {
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mt, ok := p.Tree.(interface {
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MaterializeFile(rel, dst string) error
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})
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if !ok {
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return os.ErrNotExist
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}
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return mt.MaterializeFile(p.Prefix+"/"+rel, dst)
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}
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