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.go

@@ -0,0 +1,214 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package swift
+
+import (
+	"archive/zip"
+	"fmt"
+	"io"
+	"path"
+	"regexp"
+	"strings"
+
+	"code.gitea.io/gitea/modules/json"
+	"code.gitea.io/gitea/modules/util"
+	"code.gitea.io/gitea/modules/validation"
+
+	"github.com/hashicorp/go-version"
+)
+
+var (
+	ErrMissingManifestFile    = util.NewInvalidArgumentErrorf("Package.swift file is missing")
+	ErrManifestFileTooLarge   = util.NewInvalidArgumentErrorf("Package.swift file is too large")
+	ErrInvalidManifestVersion = util.NewInvalidArgumentErrorf("manifest version is invalid")
+
+	manifestPattern     = regexp.MustCompile(`\APackage(?:@swift-(\d+(?:\.\d+)?(?:\.\d+)?))?\.swift\z`)
+	toolsVersionPattern = regexp.MustCompile(`\A// swift-tools-version:(\d+(?:\.\d+)?(?:\.\d+)?)`)
+)
+
+const (
+	maxManifestFileSize = 128 * 1024
+
+	PropertyScope         = "swift.scope"
+	PropertyName          = "swift.name"
+	PropertyRepositoryURL = "swift.repository_url"
+)
+
+// Package represents a Swift package
+type Package struct {
+	RepositoryURLs []string
+	Metadata       *Metadata
+}
+
+// Metadata represents the metadata of a Swift package
+type Metadata struct {
+	Description   string               `json:"description,omitempty"`
+	Keywords      []string             `json:"keywords,omitempty"`
+	RepositoryURL string               `json:"repository_url,omitempty"`
+	License       string               `json:"license,omitempty"`
+	Author        Person               `json:"author,omitempty"`
+	Manifests     map[string]*Manifest `json:"manifests,omitempty"`
+}
+
+// Manifest represents a Package.swift file
+type Manifest struct {
+	Content      string `json:"content"`
+	ToolsVersion string `json:"tools_version,omitempty"`
+}
+
+// https://schema.org/SoftwareSourceCode
+type SoftwareSourceCode struct {
+	Context             []string            `json:"@context"`
+	Type                string              `json:"@type"`
+	Name                string              `json:"name"`
+	Version             string              `json:"version"`
+	Description         string              `json:"description,omitempty"`
+	Keywords            []string            `json:"keywords,omitempty"`
+	CodeRepository      string              `json:"codeRepository,omitempty"`
+	License             string              `json:"license,omitempty"`
+	Author              Person              `json:"author"`
+	ProgrammingLanguage ProgrammingLanguage `json:"programmingLanguage"`
+	RepositoryURLs      []string            `json:"repositoryURLs,omitempty"`
+}
+
+// https://schema.org/ProgrammingLanguage
+type ProgrammingLanguage struct {
+	Type string `json:"@type"`
+	Name string `json:"name"`
+	URL  string `json:"url"`
+}
+
+// https://schema.org/Person
+type Person struct {
+	Type       string `json:"@type,omitempty"`
+	GivenName  string `json:"givenName,omitempty"`
+	MiddleName string `json:"middleName,omitempty"`
+	FamilyName string `json:"familyName,omitempty"`
+}
+
+func (p Person) String() string {
+	var sb strings.Builder
+	if p.GivenName != "" {
+		sb.WriteString(p.GivenName)
+	}
+	if p.MiddleName != "" {
+		if sb.Len() > 0 {
+			sb.WriteRune(' ')
+		}
+		sb.WriteString(p.MiddleName)
+	}
+	if p.FamilyName != "" {
+		if sb.Len() > 0 {
+			sb.WriteRune(' ')
+		}
+		sb.WriteString(p.FamilyName)
+	}
+	return sb.String()
+}
+
+// ParsePackage parses the Swift package upload
+func ParsePackage(sr io.ReaderAt, size int64, mr io.Reader) (*Package, error) {
+	zr, err := zip.NewReader(sr, size)
+	if err != nil {
+		return nil, err
+	}
+
+	p := &Package{
+		Metadata: &Metadata{
+			Manifests: make(map[string]*Manifest),
+		},
+	}
+
+	for _, file := range zr.File {
+		manifestMatch := manifestPattern.FindStringSubmatch(path.Base(file.Name))
+		if len(manifestMatch) == 0 {
+			continue
+		}
+
+		if file.UncompressedSize64 > maxManifestFileSize {
+			return nil, ErrManifestFileTooLarge
+		}
+
+		f, err := zr.Open(file.Name)
+		if err != nil {
+			return nil, err
+		}
+
+		content, err := io.ReadAll(f)
+
+		if err := f.Close(); err != nil {
+			return nil, err
+		}
+
+		if err != nil {
+			return nil, err
+		}
+
+		swiftVersion := ""
+		if len(manifestMatch) == 2 && manifestMatch[1] != "" {
+			v, err := version.NewSemver(manifestMatch[1])
+			if err != nil {
+				return nil, ErrInvalidManifestVersion
+			}
+			swiftVersion = TrimmedVersionString(v)
+		}
+
+		manifest := &Manifest{
+			Content: string(content),
+		}
+
+		toolsMatch := toolsVersionPattern.FindStringSubmatch(manifest.Content)
+		if len(toolsMatch) == 2 {
+			v, err := version.NewSemver(toolsMatch[1])
+			if err != nil {
+				return nil, ErrInvalidManifestVersion
+			}
+
+			manifest.ToolsVersion = TrimmedVersionString(v)
+		}
+
+		p.Metadata.Manifests[swiftVersion] = manifest
+	}
+
+	if _, found := p.Metadata.Manifests[""]; !found {
+		return nil, ErrMissingManifestFile
+	}
+
+	if mr != nil {
+		var ssc *SoftwareSourceCode
+		if err := json.NewDecoder(mr).Decode(&ssc); err != nil {
+			return nil, err
+		}
+
+		p.Metadata.Description = ssc.Description
+		p.Metadata.Keywords = ssc.Keywords
+		p.Metadata.License = ssc.License
+		p.Metadata.Author = Person{
+			GivenName:  ssc.Author.GivenName,
+			MiddleName: ssc.Author.MiddleName,
+			FamilyName: ssc.Author.FamilyName,
+		}
+
+		p.Metadata.RepositoryURL = ssc.CodeRepository
+		if !validation.IsValidURL(p.Metadata.RepositoryURL) {
+			p.Metadata.RepositoryURL = ""
+		}
+
+		p.RepositoryURLs = ssc.RepositoryURLs
+	}
+
+	return p, nil
+}
+
+// TrimmedVersionString returns the version string without the patch segment if it is zero
+func TrimmedVersionString(v *version.Version) string {
+	segments := v.Segments64()
+
+	var b strings.Builder
+	fmt.Fprintf(&b, "%d.%d", segments[0], segments[1])
+	if segments[2] != 0 {
+		fmt.Fprintf(&b, ".%d", segments[2])
+	}
+	return b.String()
+}