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|
package shelf
import (
"bufio"
"context"
"fmt"
"io"
"io/fs"
"path/filepath"
"runtime"
"slices"
"strings"
"sync"
"golang.org/x/sync/errgroup"
)
var Root = ".shelf"
type Sum map[Item]string
func Index(ignore []byte) (Sum, error) {
sum := make(Sum)
var rw sync.RWMutex
g, ctx := errgroup.WithContext(context.Background())
sem := make(chan struct{}, max(1, runtime.NumCPU()-1))
ign := newIgnore(ignore)
rootPath := filepath.Clean(Root)
walkErr := filepath.WalkDir(rootPath, func(abs string, d fs.DirEntry, err error) error {
if err != nil {
return nil
}
rel, relErr := filepath.Rel(rootPath, abs)
if relErr != nil {
return err
}
if rel == "." {
return nil
}
if ign.Match(rel, d.IsDir()) {
if d.IsDir() {
return fs.SkipDir
}
return nil
}
if d.IsDir() || !d.Type().IsRegular() {
return nil
}
select {
case <-ctx.Done():
return ctx.Err()
case sem <- struct{}{}:
}
g.Go(func() error {
defer func() { <-sem }()
hash, hashErr := hashFile(abs)
if hashErr != nil {
return hashErr
}
rw.Lock()
sum[Item(rel)] = hash
rw.Unlock()
return nil
})
return nil
})
if err := g.Wait(); err != nil {
return nil, err
}
return sum, walkErr
}
func Serialize(s Sum, w io.Writer) error {
items := make([]Item, 0, len(s))
for item := range s {
items = append(items, item)
}
slices.SortFunc(items, func(a, b Item) int {
return strings.Compare(string(a), string(b))
})
for _, item := range items {
if _, err := fmt.Fprintf(w, "%s %s\n", s[item], item); err != nil {
return err
}
}
return nil
}
func Deserialize(r io.Reader) (Sum, error) {
sum := make(Sum)
s := bufio.NewScanner(r)
for s.Scan() {
line := s.Text()
parts := strings.SplitN(line, " ", 2)
if len(parts) != 2 {
return nil, fmt.Errorf("malformed line: %q", line)
}
sum[Item(parts[1])] = parts[0]
}
return sum, s.Err()
}
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