Files
meta-core/internal/snapshot/cache.go
T
2026-04-27 10:31:11 +02:00

144 lines
3.6 KiB
Go

package snapshot
import (
"archive/zip"
"errors"
"fmt"
"io"
"log"
"os"
"path/filepath"
"strings"
)
// PluginOutputArchivePrefix is where plugin-output files live inside the ZIP.
// Trailing slash because ZIP entry names are forward-slash relative paths.
const PluginOutputArchivePrefix = "cache/plugin-output/"
// addPluginOutput walks srcDir (typically $FILES_PATH/plugin) and copies every
// file under it into zw at PluginOutputArchivePrefix + relPath.
//
// Returns the number of files added. A missing srcDir is not an error: it
// just means no plugin has produced output yet, so the section stays empty.
func addPluginOutput(zw *zip.Writer, srcDir string) (int, error) {
info, err := os.Stat(srcDir)
if errors.Is(err, os.ErrNotExist) {
return 0, nil
}
if err != nil {
return 0, fmt.Errorf("stat %s: %w", srcDir, err)
}
if !info.IsDir() {
return 0, fmt.Errorf("%s is not a directory", srcDir)
}
count := 0
err = filepath.WalkDir(srcDir, func(path string, d os.DirEntry, walkErr error) error {
if walkErr != nil {
return walkErr
}
if d.IsDir() {
return nil
}
rel, err := filepath.Rel(srcDir, path)
if err != nil {
return err
}
entry := PluginOutputArchivePrefix + filepath.ToSlash(rel)
w, err := zw.Create(entry)
if err != nil {
return err
}
f, err := os.Open(path)
if err != nil {
return err
}
defer f.Close()
if _, err := io.Copy(w, f); err != nil {
return err
}
count++
return nil
})
if err != nil {
return count, fmt.Errorf("walk %s: %w", srcDir, err)
}
return count, nil
}
// extractPluginOutput pulls every entry under PluginOutputArchivePrefix from
// the ZIP and writes it under dstDir. Existing files are overwritten when
// overwrite=true; otherwise they're left alone (treats existing files as the
// "mine wins" choice — same toggle the metadata import uses).
//
// Path traversal is rejected: any entry whose relative path resolves outside
// dstDir is skipped with a warning.
func extractPluginOutput(zr *zip.Reader, dstDir string, overwrite bool) (written int, skipped int, err error) {
if dstDir == "" {
return 0, 0, fmt.Errorf("plugin-output destination dir is empty")
}
if err := os.MkdirAll(dstDir, 0o755); err != nil {
return 0, 0, fmt.Errorf("mkdir %s: %w", dstDir, err)
}
cleanRoot, err := filepath.Abs(dstDir)
if err != nil {
return 0, 0, fmt.Errorf("abs %s: %w", dstDir, err)
}
for _, f := range zr.File {
if !strings.HasPrefix(f.Name, PluginOutputArchivePrefix) {
continue
}
if strings.HasSuffix(f.Name, "/") {
continue
}
rel := strings.TrimPrefix(f.Name, PluginOutputArchivePrefix)
dst := filepath.Join(cleanRoot, filepath.FromSlash(rel))
// Reject anything that escapes the dst root.
if !strings.HasPrefix(dst, cleanRoot+string(os.PathSeparator)) && dst != cleanRoot {
log.Printf("[Snapshot] import: skipping path-escaping entry %q", f.Name)
skipped++
continue
}
if !overwrite {
if _, err := os.Stat(dst); err == nil {
skipped++
continue
}
}
if err := os.MkdirAll(filepath.Dir(dst), 0o755); err != nil {
return written, skipped, fmt.Errorf("mkdir for %s: %w", dst, err)
}
if err := writeZipFile(f, dst); err != nil {
return written, skipped, err
}
written++
}
return written, skipped, nil
}
func writeZipFile(f *zip.File, dst string) error {
rc, err := f.Open()
if err != nil {
return fmt.Errorf("open zip entry %s: %w", f.Name, err)
}
defer rc.Close()
out, err := os.Create(dst)
if err != nil {
return fmt.Errorf("create %s: %w", dst, err)
}
defer out.Close()
if _, err := io.Copy(out, rc); err != nil {
return fmt.Errorf("write %s: %w", dst, err)
}
return nil
}