Add Swift package registry (#22404)

This PR adds a [Swift](https://www.swift.org/) package registry.


![grafik](https://user-images.githubusercontent.com/1666336/211842523-07521cbd-8fb6-400f-820c-ee8048b05ae8.png)

modules/packages/swift/metadata_test.go

@@ -0,0 +1,144 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package swift
+
+import (
+	"archive/zip"
+	"bytes"
+	"strings"
+	"testing"
+
+	"github.com/hashicorp/go-version"
+	"github.com/stretchr/testify/assert"
+)
+
+const (
+	packageName          = "gitea"
+	packageVersion       = "1.0.1"
+	packageDescription   = "Package Description"
+	packageRepositoryURL = "https://gitea.io/gitea/gitea"
+	packageAuthor        = "KN4CK3R"
+	packageLicense       = "MIT"
+)
+
+func TestParsePackage(t *testing.T) {
+	createArchive := func(files map[string][]byte) *bytes.Reader {
+		var buf bytes.Buffer
+		zw := zip.NewWriter(&buf)
+		for filename, content := range files {
+			w, _ := zw.Create(filename)
+			w.Write(content)
+		}
+		zw.Close()
+		return bytes.NewReader(buf.Bytes())
+	}
+
+	t.Run("MissingManifestFile", func(t *testing.T) {
+		data := createArchive(map[string][]byte{"dummy.txt": {}})
+
+		p, err := ParsePackage(data, data.Size(), nil)
+		assert.Nil(t, p)
+		assert.ErrorIs(t, err, ErrMissingManifestFile)
+	})
+
+	t.Run("ManifestFileTooLarge", func(t *testing.T) {
+		data := createArchive(map[string][]byte{
+			"Package.swift": make([]byte, maxManifestFileSize+1),
+		})
+
+		p, err := ParsePackage(data, data.Size(), nil)
+		assert.Nil(t, p)
+		assert.ErrorIs(t, err, ErrManifestFileTooLarge)
+	})
+
+	t.Run("WithoutMetadata", func(t *testing.T) {
+		content1 := "// swift-tools-version:5.7\n//\n//  Package.swift"
+		content2 := "// swift-tools-version:5.6\n//\n//  Package@swift-5.6.swift"
+
+		data := createArchive(map[string][]byte{
+			"Package.swift":           []byte(content1),
+			"Package@swift-5.5.swift": []byte(content2),
+		})
+
+		p, err := ParsePackage(data, data.Size(), nil)
+		assert.NotNil(t, p)
+		assert.NoError(t, err)
+
+		assert.NotNil(t, p.Metadata)
+		assert.Empty(t, p.RepositoryURLs)
+		assert.Len(t, p.Metadata.Manifests, 2)
+		m := p.Metadata.Manifests[""]
+		assert.Equal(t, "5.7", m.ToolsVersion)
+		assert.Equal(t, content1, m.Content)
+		m = p.Metadata.Manifests["5.5"]
+		assert.Equal(t, "5.6", m.ToolsVersion)
+		assert.Equal(t, content2, m.Content)
+	})
+
+	t.Run("WithMetadata", func(t *testing.T) {
+		data := createArchive(map[string][]byte{
+			"Package.swift": []byte("// swift-tools-version:5.7\n//\n//  Package.swift"),
+		})
+
+		p, err := ParsePackage(
+			data,
+			data.Size(),
+			strings.NewReader(`{"name":"`+packageName+`","version":"`+packageVersion+`","description":"`+packageDescription+`","keywords":["swift","package"],"license":"`+packageLicense+`","codeRepository":"`+packageRepositoryURL+`","author":{"givenName":"`+packageAuthor+`"},"repositoryURLs":["`+packageRepositoryURL+`"]}`),
+		)
+		assert.NotNil(t, p)
+		assert.NoError(t, err)
+
+		assert.NotNil(t, p.Metadata)
+		assert.Len(t, p.Metadata.Manifests, 1)
+		m := p.Metadata.Manifests[""]
+		assert.Equal(t, "5.7", m.ToolsVersion)
+
+		assert.Equal(t, packageDescription, p.Metadata.Description)
+		assert.ElementsMatch(t, []string{"swift", "package"}, p.Metadata.Keywords)
+		assert.Equal(t, packageLicense, p.Metadata.License)
+		assert.Equal(t, packageAuthor, p.Metadata.Author.GivenName)
+		assert.Equal(t, packageRepositoryURL, p.Metadata.RepositoryURL)
+		assert.ElementsMatch(t, []string{packageRepositoryURL}, p.RepositoryURLs)
+	})
+}
+
+func TestTrimmedVersionString(t *testing.T) {
+	cases := []struct {
+		Version  *version.Version
+		Expected string
+	}{
+		{
+			Version:  version.Must(version.NewVersion("1")),
+			Expected: "1.0",
+		},
+		{
+			Version:  version.Must(version.NewVersion("1.0")),
+			Expected: "1.0",
+		},
+		{
+			Version:  version.Must(version.NewVersion("1.0.0")),
+			Expected: "1.0",
+		},
+		{
+			Version:  version.Must(version.NewVersion("1.0.1")),
+			Expected: "1.0.1",
+		},
+		{
+			Version:  version.Must(version.NewVersion("1.0+meta")),
+			Expected: "1.0",
+		},
+		{
+			Version:  version.Must(version.NewVersion("1.0.0+meta")),
+			Expected: "1.0",
+		},
+		{
+			Version:  version.Must(version.NewVersion("1.0.1+meta")),
+			Expected: "1.0.1",
+		},
+	}
+
+	for _, c := range cases {
+		assert.Equal(t, c.Expected, TrimmedVersionString(c.Version))
+	}
+}