moved build_map to db file as it contains matching functions and db logic

internal/repomaint/db.go

@@ -0,0 +1,119 @@
+package repomaint
+
+import (
+	"archive/tar"
+	"bufio"
+	"compress/gzip"
+	"fmt"
+	"io"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"slices"
+	"strings"
+)
+
+func (r *RepoSync) buildMap(repo string) (map[string]string, error) {
+	// create slice all filenames in repo
+	pkgs, err := r.cachedPkgs(repo)
+	if err != nil {
+		return nil, err
+	}
+
+	// open db file
+	db, fr, gzr, err := r.openDb(repo)
+	if err != nil {
+		return nil, err
+	}
+	defer fr.Close()
+	defer gzr.Close()
+
+	// for entry in db
+	pkgMap := make(map[string]string)
+	for {
+		hdr, err := db.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, err
+		}
+		if filepath.Base(hdr.Name) != "desc" {
+			continue
+		}
+		if !slices.Contains(pkgs, filepath.Dir(hdr.Name)) {
+			continue
+		}
+		pkgName, pkgFile, err := parseDesc(db)
+		if err != nil {
+			slog.Warn("failed to parse desc file", "pkg", hdr.Name, "err", err)
+			continue
+		}
+
+		pkgMap[pkgName] = pkgFile
+	}
+
+	return pkgMap, nil
+}
+
+func (r *RepoSync) cachedPkgs(repo string) ([]string, error) {
+	repoPath := filepath.Join(repo, repoArch)
+	f, err := r.root.Open(repoPath)
+	if err != nil {
+		return nil, err
+	}
+	files, err := f.ReadDir(-1)
+	if err != nil {
+		return nil, err
+	}
+	var pkgs []string
+	for _, f := range files {
+		pkg := strings.TrimSuffix(f.Name(), pkgSuffix)
+		pkgs = append(pkgs, pkg)
+	}
+
+	return pkgs, nil
+}
+
+func (r *RepoSync) openDb(repo string) (*tar.Reader, *os.File, *gzip.Reader, error) {
+
+	repoPath := filepath.Join(repo, repoArch)
+	path := filepath.Join(repoPath, repo+dbSuffix)
+	f, err := r.root.Open(path)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	gr, err := gzip.NewReader(f)
+	if err != nil {
+		f.Close()
+		return nil, nil, nil, err
+	}
+	tr := tar.NewReader(gr)
+
+	return tr, f, gr, nil
+}
+
+func parseDesc(f io.Reader) (pkgname, filename string, err error) {
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		switch scanner.Text() {
+		case "%NAME%":
+			scanner.Scan()
+			pkgname = scanner.Text()
+		case "%FILENAME%":
+			scanner.Scan()
+			filename = scanner.Text()
+		}
+		if pkgname != "" && filename != "" {
+			break
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return "", "", err
+	}
+	if pkgname == "" || filename == "" {
+		return "", "", fmt.Errorf("incomplete or corrupt desc")
+	}
+
+	return pkgname, filename, nil
+}