Initial Commit

internal/index/dnf.go

@@ -0,0 +1,154 @@
+/*
+ * distrohop - A utility for correlating and identifying equivalent software
+ * packages across different Linux distributions
+ *
+ * Copyright (C) 2025 Elara Ivy <elara@elara.ws>
+ *
+ * This file is part of distrohop.
+ *
+ * distrohop is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * distrohop is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with distrohop.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package index
+
+import (
+	"bufio"
+	"context"
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"github.com/mholt/archives"
+	"go.elara.ws/distrohop/internal/tags"
+)
+
+type repomd struct {
+	Locations []location `xml:"data>location"`
+}
+
+type location struct {
+	Href string `xml:"href,attr"`
+}
+
+func (r repomd) getGzipFile() string {
+	for _, loc := range r.Locations {
+		if strings.HasSuffix(loc.Href, "filelists.xml.gz") {
+			return loc.Href
+		}
+	}
+	return "<unknown>"
+}
+
+type DNF struct{}
+
+func (DNF) Name() string {
+	return "dnf"
+}
+
+func (DNF) IndexURL(baseURL, version, repo, arch string) ([]string, error) {
+	u, err := url.ParseRequestURI(baseURL)
+	if err != nil {
+		return nil, err
+	}
+	repomdPath := fmt.Sprintf("/pub/fedora/linux/releases/%s/%s/%s/os/repodata/repomd.xml", version, repo, arch)
+	u.Path = repomdPath
+
+	res, err := http.Get(u.String())
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+
+	var data repomd
+	err = xml.NewDecoder(res.Body).Decode(&data)
+	if err != nil {
+		return nil, err
+	}
+
+	gzipFile := data.getGzipFile()
+	if gzipFile == "" {
+		return nil, errors.New("no gzip file found in repomd.xml")
+	}
+
+	u.Path = fmt.Sprintf("/pub/fedora/linux/releases/%s/%s/%s/os/%s", version, repo, arch, gzipFile)
+	return []string{u.String()}, nil
+}
+
+func (DNF) ReadPkgData(r io.Reader, out chan Record) {
+	ctx := context.Background()
+	format, r, err := archives.Identify(ctx, "", r)
+	if err != nil {
+		out <- Record{Error: err}
+		return
+	}
+
+	decomp, ok := format.(archives.Decompressor)
+	if !ok {
+		out <- Record{Error: errors.New("downloaded index is not a valid compressed file")}
+		return
+	}
+
+	dr, err := decomp.OpenReader(r)
+	if err != nil {
+		out <- Record{Error: err}
+		return
+	}
+	defer dr.Close()
+
+	br := bufio.NewReader(dr)
+	var currentPkg string
+
+	for {
+		line, err := br.ReadString('\n')
+		if errors.Is(err, io.EOF) {
+			close(out)
+			break
+		} else if err != nil {
+			out <- Record{Error: err}
+			return
+		}
+		line = strings.TrimSpace(line)
+
+		switch {
+		case strings.HasPrefix(line, "<file"):
+			// Skip directories and symlinks
+			if strings.HasPrefix(line[5:], `type="dir"`) || line[5] == 'l' {
+				continue
+			}
+
+			start := strings.IndexByte(line, '>') + 1
+			end := strings.LastIndexByte(line, '<')
+			fpath := line[start:end]
+
+			if strings.Contains(fpath, ".build-id") {
+				continue
+			}
+
+			out <- Record{
+				Name: currentPkg,
+				Tags: tags.Generate(fpath),
+			}
+		case strings.HasPrefix(line, "<package"):
+			start := strings.LastIndex(line, `name="`) + 6
+			end := start + strings.IndexByte(line[start:], '"')
+			currentPkg = line[start:end]
+		default:
+			continue
+		}
+	}
+}