Add Arch package registry (#32692)

Close #25037
Close #31037

This PR adds a Arch package registry usable with pacman.

![grafik](https://github.com/user-attachments/assets/81cdb0c2-02f9-4733-bee2-e48af6b45224)

Rewrite of #25396 and #31037. You can follow [this
tutorial](https://wiki.archlinux.org/title/Creating_packages) to build a
package for testing.

Docs PR: https://gitea.com/gitea/docs/pulls/111

Co-authored-by: [d1nch8g@ion.lc](mailto:d1nch8g@ion.lc)
Co-authored-by: @ExplodingDragon

---------

Co-authored-by: dancheg97 <dancheg97@fmnx.su>
Co-authored-by: dragon <ExplodingFKL@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/packages/arch/metadata_test.go

@@ -0,0 +1,157 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package arch
+
+import (
+	"archive/tar"
+	"bytes"
+	"compress/gzip"
+	"io"
+	"testing"
+
+	"github.com/klauspost/compress/zstd"
+	"github.com/stretchr/testify/assert"
+	"github.com/ulikunitz/xz"
+)
+
+const (
+	packageName        = "gitea"
+	packageVersion     = "1.0.1"
+	packageDescription = "Package Description"
+	packageProjectURL  = "https://gitea.com"
+	packagePackager    = "KN4CK3R <packager@gitea.com>"
+)
+
+func createPKGINFOContent(name, version string) []byte {
+	return []byte(`pkgname = ` + name + `
+pkgbase = ` + name + `
+pkgver = ` + version + `
+pkgdesc = ` + packageDescription + `
+url = ` + packageProjectURL + `
+# comment
+group=group
+builddate = 1678834800
+size = 123456
+arch = x86_64
+license = MIT
+packager = ` + packagePackager + `
+depend = common
+xdata = value
+depend = gitea
+provides = common
+provides = gitea
+optdepend = hex
+checkdepend = common
+makedepend = cmake
+backup = usr/bin/paket1`)
+}
+
+func TestParsePackage(t *testing.T) {
+	createPackage := func(compression string, files map[string][]byte) io.Reader {
+		var buf bytes.Buffer
+		var cw io.WriteCloser
+		switch compression {
+		case "zst":
+			cw, _ = zstd.NewWriter(&buf)
+		case "xz":
+			cw, _ = xz.NewWriter(&buf)
+		case "gz":
+			cw = gzip.NewWriter(&buf)
+		}
+		tw := tar.NewWriter(cw)
+
+		for name, content := range files {
+			hdr := &tar.Header{
+				Name: name,
+				Mode: 0o600,
+				Size: int64(len(content)),
+			}
+			tw.WriteHeader(hdr)
+			tw.Write(content)
+		}
+
+		tw.Close()
+		cw.Close()
+
+		return &buf
+	}
+
+	for _, c := range []string{"gz", "xz", "zst"} {
+		t.Run(c, func(t *testing.T) {
+			t.Run("MissingPKGINFOFile", func(t *testing.T) {
+				data := createPackage(c, map[string][]byte{"dummy.txt": {}})
+
+				pp, err := ParsePackage(data)
+				assert.Nil(t, pp)
+				assert.ErrorIs(t, err, ErrMissingPKGINFOFile)
+			})
+
+			t.Run("InvalidPKGINFOFile", func(t *testing.T) {
+				data := createPackage(c, map[string][]byte{".PKGINFO": {}})
+
+				pp, err := ParsePackage(data)
+				assert.Nil(t, pp)
+				assert.ErrorIs(t, err, ErrInvalidName)
+			})
+
+			t.Run("Valid", func(t *testing.T) {
+				data := createPackage(c, map[string][]byte{
+					".PKGINFO":        createPKGINFOContent(packageName, packageVersion),
+					"/test/dummy.txt": {},
+				})
+
+				p, err := ParsePackage(data)
+				assert.NoError(t, err)
+				assert.NotNil(t, p)
+
+				assert.ElementsMatch(t, []string{"/test/dummy.txt"}, p.FileMetadata.Files)
+			})
+		})
+	}
+}
+
+func TestParsePackageInfo(t *testing.T) {
+	t.Run("InvalidName", func(t *testing.T) {
+		data := createPKGINFOContent("", packageVersion)
+
+		p, err := ParsePackageInfo(bytes.NewReader(data))
+		assert.Nil(t, p)
+		assert.ErrorIs(t, err, ErrInvalidName)
+	})
+
+	t.Run("InvalidVersion", func(t *testing.T) {
+		data := createPKGINFOContent(packageName, "")
+
+		p, err := ParsePackageInfo(bytes.NewReader(data))
+		assert.Nil(t, p)
+		assert.ErrorIs(t, err, ErrInvalidVersion)
+	})
+
+	t.Run("Valid", func(t *testing.T) {
+		data := createPKGINFOContent(packageName, packageVersion)
+
+		p, err := ParsePackageInfo(bytes.NewReader(data))
+		assert.NoError(t, err)
+		assert.NotNil(t, p)
+
+		assert.Equal(t, packageName, p.Name)
+		assert.Equal(t, packageName, p.FileMetadata.Base)
+		assert.Equal(t, packageVersion, p.Version)
+		assert.Equal(t, packageDescription, p.VersionMetadata.Description)
+		assert.Equal(t, packagePackager, p.FileMetadata.Packager)
+		assert.Equal(t, packageProjectURL, p.VersionMetadata.ProjectURL)
+		assert.ElementsMatch(t, []string{"MIT"}, p.VersionMetadata.Licenses)
+		assert.EqualValues(t, 1678834800, p.FileMetadata.BuildDate)
+		assert.EqualValues(t, 123456, p.FileMetadata.InstalledSize)
+		assert.Equal(t, "x86_64", p.FileMetadata.Architecture)
+		assert.ElementsMatch(t, []string{"value"}, p.FileMetadata.XData)
+		assert.ElementsMatch(t, []string{"group"}, p.FileMetadata.Groups)
+		assert.ElementsMatch(t, []string{"common", "gitea"}, p.FileMetadata.Provides)
+		assert.ElementsMatch(t, []string{"common", "gitea"}, p.FileMetadata.Depends)
+		assert.ElementsMatch(t, []string{"hex"}, p.FileMetadata.OptDepends)
+		assert.ElementsMatch(t, []string{"common"}, p.FileMetadata.CheckDepends)
+		assert.ElementsMatch(t, []string{"cmake"}, p.FileMetadata.MakeDepends)
+		assert.ElementsMatch(t, []string{"usr/bin/paket1"}, p.FileMetadata.Backup)
+	})
+}