Initial Commit

internal/index/apt.go

@@ -0,0 +1,114 @@
+/*
+ * 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"
+	"errors"
+	"io"
+	"net/url"
+	"strings"
+
+	"github.com/mholt/archives"
+	"go.elara.ws/distrohop/internal/tags"
+)
+
+type APT struct{}
+
+func (APT) Name() string {
+	return "apt"
+}
+
+func (APT) IndexURL(baseURL, version, repo, arch string) ([]string, error) {
+	indexURL, err := url.JoinPath(baseURL, "dists", version, repo, "Contents-"+arch+".gz")
+	if err != nil {
+		return nil, err
+	}
+	// Before Debian Wheezy, the path to Contents indices didn't include $COMP/repo, so we need to try
+	// both the new and old URL formats. Ubuntu also still uses the pre-Debian-Wheezy convention.
+	deprecatedURL, err := url.JoinPath(baseURL, "dists", version, "Contents-"+arch+".gz")
+	if err != nil {
+		return nil, err
+	}
+	return []string{indexURL, deprecatedURL}, nil
+}
+
+func (APT) 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)
+	for {
+		line, err := br.ReadString('\n')
+		if errors.Is(err, io.EOF) {
+			close(out)
+			break
+		} else if err != nil {
+			out <- Record{Error: err}
+			return
+		}
+
+		lastSpaceIdx := strings.LastIndexByte(line, ' ')
+		if lastSpaceIdx == -1 {
+			continue
+		}
+
+		fpath := "/" + strings.TrimSpace(line[:lastSpaceIdx])
+		names := strings.Split(strings.TrimSpace(line[lastSpaceIdx+1:]), ",")
+		for _, name := range names {
+			slashIdx := strings.LastIndexByte(name, '/')
+			if slashIdx != -1 {
+				name = name[slashIdx+1:]
+			}
+
+			if strings.Contains(fpath, "changelog.Debian") ||
+				strings.Contains(fpath, "README.Debian") ||
+				strings.Contains(fpath, "NEWS.Debian.gz") {
+				continue
+			}
+
+			out <- Record{
+				Name: name,
+				Tags: tags.Generate(fpath),
+			}
+		}
+	}
+}