1 files changed, 113 insertions, 0 deletions
diff --git a/modules/repository/license.go b/modules/repository/license.go
new file mode 100644
index 00000000..6ac3547e
--- /dev/null
+++ b/modules/repository/license.go
@@ -0,0 +1,113 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package repository
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"regexp"
+	"strings"
+
+	"code.gitea.io/gitea/modules/options"
+)
+
+type LicenseValues struct {
+	Owner string
+	Email string
+	Repo  string
+	Year  string
+}
+
+func GetLicense(name string, values *LicenseValues) ([]byte, error) {
+	data, err := options.License(name)
+	if err != nil {
+		return nil, fmt.Errorf("GetRepoInitFile[%s]: %w", name, err)
+	}
+	return fillLicensePlaceholder(name, values, data), nil
+}
+
+func fillLicensePlaceholder(name string, values *LicenseValues, origin []byte) []byte {
+	placeholder := getLicensePlaceholder(name)
+
+	scanner := bufio.NewScanner(bytes.NewReader(origin))
+	output := bytes.NewBuffer(nil)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if placeholder.MatchLine == nil || placeholder.MatchLine.MatchString(line) {
+			for _, v := range placeholder.Owner {
+				line = strings.ReplaceAll(line, v, values.Owner)
+			}
+			for _, v := range placeholder.Email {
+				line = strings.ReplaceAll(line, v, values.Email)
+			}
+			for _, v := range placeholder.Repo {
+				line = strings.ReplaceAll(line, v, values.Repo)
+			}
+			for _, v := range placeholder.Year {
+				line = strings.ReplaceAll(line, v, values.Year)
+			}
+		}
+		output.WriteString(line + "\n")
+	}
+
+	return output.Bytes()
+}
+
+type licensePlaceholder struct {
+	Owner     []string
+	Email     []string
+	Repo      []string
+	Year      []string
+	MatchLine *regexp.Regexp
+}
+
+func getLicensePlaceholder(name string) *licensePlaceholder {
+	// Some universal placeholders.
+	// If you want to add a new one, make sure you have check it by `grep -r 'NEW_WORD' options/license` and all of them are placeholders.
+	ret := &licensePlaceholder{
+		Owner: []string{
+			"<name of author>",
+			"<owner>",
+			"[NAME]",
+			"[name of copyright owner]",
+			"[name of copyright holder]",
+			"<COPYRIGHT HOLDERS>",
+			"<copyright holders>",
+			"<AUTHOR>",
+			"<author's name or designee>",
+			"[one or more legally recognised persons or entities offering the Work under the terms and conditions of this Licence]",
+		},
+		Email: []string{
+			"[EMAIL]",
+		},
+		Repo: []string{
+			"<program>",
+			"<one line to give the program's name and a brief idea of what it does.>",
+		},
+		Year: []string{
+			"<year>",
+			"[YEAR]",
+			"{YEAR}",
+			"[yyyy]",
+			"[Year]",
+			"[year]",
+		},
+	}
+
+	// Some special placeholders for specific licenses.
+	// It's unsafe to apply them to all licenses.
+	switch name {
+	case "0BSD":
+		return &licensePlaceholder{
+			Owner:     []string{"AUTHOR"},
+			Email:     []string{"EMAIL"},
+			Year:      []string{"YEAR"},
+			MatchLine: regexp.MustCompile(`Copyright \(C\) YEAR by AUTHOR EMAIL`), // there is another AUTHOR in the file, but it's not a placeholder
+		}
+
+		// Other special placeholders can be added here.
+	}
+	return ret
+}