Adding upstream version 9.0.0.

Signed-off-by: Daniel Baumann <daniel@debian.org>

40 files changed, 3347 insertions, 0 deletions

diff --git a/modules/util/color.go b/modules/util/color.go
new file mode 100644
index 0000000..9c520dc
--- /dev/null
+++ b/modules/util/color.go
@@ -0,0 +1,57 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+package util
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// Get color as RGB values in 0..255 range from the hex color string (with or without #)
+func HexToRBGColor(colorString string) (float64, float64, float64) {
+	hexString := colorString
+	if strings.HasPrefix(colorString, "#") {
+		hexString = colorString[1:]
+	}
+	// only support transfer of rgb, rgba, rrggbb and rrggbbaa
+	// if not in these formats, use default values 0, 0, 0
+	if len(hexString) != 3 && len(hexString) != 4 && len(hexString) != 6 && len(hexString) != 8 {
+		return 0, 0, 0
+	}
+	if len(hexString) == 3 || len(hexString) == 4 {
+		hexString = fmt.Sprintf("%c%c%c%c%c%c", hexString[0], hexString[0], hexString[1], hexString[1], hexString[2], hexString[2])
+	}
+	if len(hexString) == 8 {
+		hexString = hexString[0:6]
+	}
+	color, err := strconv.ParseUint(hexString, 16, 64)
+	if err != nil {
+		return 0, 0, 0
+	}
+	r := float64(uint8(0xFF & (uint32(color) >> 16)))
+	g := float64(uint8(0xFF & (uint32(color) >> 8)))
+	b := float64(uint8(0xFF & uint32(color)))
+	return r, g, b
+}
+
+// Returns relative luminance for a SRGB color - https://en.wikipedia.org/wiki/Relative_luminance
+// Keep this in sync with web_src/js/utils/color.js
+func GetRelativeLuminance(color string) float64 {
+	r, g, b := HexToRBGColor(color)
+	return (0.2126729*r + 0.7151522*g + 0.0721750*b) / 255
+}
+
+func UseLightText(backgroundColor string) bool {
+	return GetRelativeLuminance(backgroundColor) < 0.453
+}
+
+// Given a background color, returns a black or white foreground color that the highest
+// contrast ratio. In the future, the APCA contrast function, or CSS `contrast-color` will be better.
+// https://github.com/color-js/color.js/blob/eb7b53f7a13bb716ec8b28c7a56f052cd599acd9/src/contrast/APCA.js#L42
+func ContrastColor(backgroundColor string) string {
+	if UseLightText(backgroundColor) {
+		return "#fff"
+	}
+	return "#000"
+}
diff --git a/modules/util/color_test.go b/modules/util/color_test.go
new file mode 100644
index 0000000..abd5551
--- /dev/null
+++ b/modules/util/color_test.go
@@ -0,0 +1,63 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+package util
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_HexToRBGColor(t *testing.T) {
+	cases := []struct {
+		colorString string
+		expectedR   float64
+		expectedG   float64
+		expectedB   float64
+	}{
+		{"2b8685", 43, 134, 133},
+		{"1e1", 17, 238, 17},
+		{"#1e1", 17, 238, 17},
+		{"1e16", 17, 238, 17},
+		{"3bb6b3", 59, 182, 179},
+		{"#3bb6b399", 59, 182, 179},
+		{"#0", 0, 0, 0},
+		{"#00000", 0, 0, 0},
+		{"#1234567", 0, 0, 0},
+	}
+	for n, c := range cases {
+		r, g, b := HexToRBGColor(c.colorString)
+		assert.InDelta(t, c.expectedR, r, 0, "case %d: error R should match: expected %f, but get %f", n, c.expectedR, r)
+		assert.InDelta(t, c.expectedG, g, 0, "case %d: error G should match: expected %f, but get %f", n, c.expectedG, g)
+		assert.InDelta(t, c.expectedB, b, 0, "case %d: error B should match: expected %f, but get %f", n, c.expectedB, b)
+	}
+}
+
+func Test_UseLightText(t *testing.T) {
+	cases := []struct {
+		color    string
+		expected string
+	}{
+		{"#d73a4a", "#fff"},
+		{"#0075ca", "#fff"},
+		{"#cfd3d7", "#000"},
+		{"#a2eeef", "#000"},
+		{"#7057ff", "#fff"},
+		{"#008672", "#fff"},
+		{"#e4e669", "#000"},
+		{"#d876e3", "#000"},
+		{"#ffffff", "#000"},
+		{"#2b8684", "#fff"},
+		{"#2b8786", "#fff"},
+		{"#2c8786", "#000"},
+		{"#3bb6b3", "#000"},
+		{"#7c7268", "#fff"},
+		{"#7e716c", "#fff"},
+		{"#81706d", "#fff"},
+		{"#807070", "#fff"},
+		{"#84b6eb", "#000"},
+	}
+	for n, c := range cases {
+		assert.Equal(t, c.expected, ContrastColor(c.color), "case %d: error should match", n)
+	}
+}
diff --git a/modules/util/error.go b/modules/util/error.go
new file mode 100644
index 0000000..0f35971
--- /dev/null
+++ b/modules/util/error.go
@@ -0,0 +1,65 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"errors"
+	"fmt"
+)
+
+// Common Errors forming the base of our error system
+//
+// Many Errors returned by Gitea can be tested against these errors
+// using errors.Is.
+var (
+	ErrInvalidArgument  = errors.New("invalid argument")
+	ErrPermissionDenied = errors.New("permission denied")
+	ErrAlreadyExist     = errors.New("resource already exists")
+	ErrNotExist         = errors.New("resource does not exist")
+)
+
+// SilentWrap provides a simple wrapper for a wrapped error where the wrapped error message plays no part in the error message
+// Especially useful for "untyped" errors created with "errors.New(…)" that can be classified as 'invalid argument', 'permission denied', 'exists already', or 'does not exist'
+type SilentWrap struct {
+	Message string
+	Err     error
+}
+
+// Error returns the message
+func (w SilentWrap) Error() string {
+	return w.Message
+}
+
+// Unwrap returns the underlying error
+func (w SilentWrap) Unwrap() error {
+	return w.Err
+}
+
+// NewSilentWrapErrorf returns an error that formats as the given text but unwraps as the provided error
+func NewSilentWrapErrorf(unwrap error, message string, args ...any) error {
+	if len(args) == 0 {
+		return SilentWrap{Message: message, Err: unwrap}
+	}
+	return SilentWrap{Message: fmt.Sprintf(message, args...), Err: unwrap}
+}
+
+// NewInvalidArgumentErrorf returns an error that formats as the given text but unwraps as an ErrInvalidArgument
+func NewInvalidArgumentErrorf(message string, args ...any) error {
+	return NewSilentWrapErrorf(ErrInvalidArgument, message, args...)
+}
+
+// NewPermissionDeniedErrorf returns an error that formats as the given text but unwraps as an ErrPermissionDenied
+func NewPermissionDeniedErrorf(message string, args ...any) error {
+	return NewSilentWrapErrorf(ErrPermissionDenied, message, args...)
+}
+
+// NewAlreadyExistErrorf returns an error that formats as the given text but unwraps as an ErrAlreadyExist
+func NewAlreadyExistErrorf(message string, args ...any) error {
+	return NewSilentWrapErrorf(ErrAlreadyExist, message, args...)
+}
+
+// NewNotExistErrorf returns an error that formats as the given text but unwraps as an ErrNotExist
+func NewNotExistErrorf(message string, args ...any) error {
+	return NewSilentWrapErrorf(ErrNotExist, message, args...)
+}
diff --git a/modules/util/file_unix.go b/modules/util/file_unix.go
new file mode 100644
index 0000000..79a29c8
--- /dev/null
+++ b/modules/util/file_unix.go
@@ -0,0 +1,27 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+//go:build !windows
+
+package util
+
+import (
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+var defaultUmask int
+
+func init() {
+	// at the moment, the umask could only be gotten by calling unix.Umask(newUmask)
+	// use 0o077 as temp new umask to reduce the risks if this umask is used anywhere else before the correct umask is recovered
+	tempUmask := 0o077
+	defaultUmask = unix.Umask(tempUmask)
+	unix.Umask(defaultUmask)
+}
+
+func ApplyUmask(f string, newMode os.FileMode) error {
+	mod := newMode & ^os.FileMode(defaultUmask)
+	return os.Chmod(f, mod)
+}
diff --git a/modules/util/file_unix_test.go b/modules/util/file_unix_test.go
new file mode 100644
index 0000000..d60082a
--- /dev/null
+++ b/modules/util/file_unix_test.go
@@ -0,0 +1,36 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+//go:build !windows
+
+package util
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestApplyUmask(t *testing.T) {
+	f, err := os.CreateTemp(t.TempDir(), "test-filemode-")
+	require.NoError(t, err)
+
+	err = os.Chmod(f.Name(), 0o777)
+	require.NoError(t, err)
+	st, err := os.Stat(f.Name())
+	require.NoError(t, err)
+	assert.EqualValues(t, 0o777, st.Mode().Perm()&0o777)
+
+	oldDefaultUmask := defaultUmask
+	defaultUmask = 0o037
+	defer func() {
+		defaultUmask = oldDefaultUmask
+	}()
+	err = ApplyUmask(f.Name(), os.ModePerm)
+	require.NoError(t, err)
+	st, err = os.Stat(f.Name())
+	require.NoError(t, err)
+	assert.EqualValues(t, 0o740, st.Mode().Perm()&0o777)
+}
diff --git a/modules/util/file_windows.go b/modules/util/file_windows.go
new file mode 100644
index 0000000..77a33d3
--- /dev/null
+++ b/modules/util/file_windows.go
@@ -0,0 +1,15 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+//go:build windows
+
+package util
+
+import (
+	"os"
+)
+
+func ApplyUmask(f string, newMode os.FileMode) error {
+	// do nothing for Windows, because Windows doesn't use umask
+	return nil
+}
diff --git a/modules/util/filebuffer/file_backed_buffer.go b/modules/util/filebuffer/file_backed_buffer.go
new file mode 100644
index 0000000..739543e
--- /dev/null
+++ b/modules/util/filebuffer/file_backed_buffer.go
@@ -0,0 +1,156 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package filebuffer
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"math"
+	"os"
+)
+
+var (
+	// ErrInvalidMemorySize occurs if the memory size is not in a valid range
+	ErrInvalidMemorySize = errors.New("Memory size must be greater 0 and lower math.MaxInt32")
+	// ErrWriteAfterRead occurs if Write is called after a read operation
+	ErrWriteAfterRead = errors.New("Write is unsupported after a read operation")
+)
+
+type readAtSeeker interface {
+	io.ReadSeeker
+	io.ReaderAt
+}
+
+// FileBackedBuffer uses a memory buffer with a fixed size.
+// If more data is written a temporary file is used instead.
+// It implements io.ReadWriteCloser, io.ReadSeekCloser and io.ReaderAt
+type FileBackedBuffer struct {
+	maxMemorySize int64
+	size          int64
+	buffer        bytes.Buffer
+	file          *os.File
+	reader        readAtSeeker
+}
+
+// New creates a file backed buffer with a specific maximum memory size
+func New(maxMemorySize int) (*FileBackedBuffer, error) {
+	if maxMemorySize < 0 || maxMemorySize > math.MaxInt32 {
+		return nil, ErrInvalidMemorySize
+	}
+
+	return &FileBackedBuffer{
+		maxMemorySize: int64(maxMemorySize),
+	}, nil
+}
+
+// CreateFromReader creates a file backed buffer and copies the provided reader data into it.
+func CreateFromReader(r io.Reader, maxMemorySize int) (*FileBackedBuffer, error) {
+	b, err := New(maxMemorySize)
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = io.Copy(b, r)
+	if err != nil {
+		return nil, err
+	}
+
+	return b, nil
+}
+
+// Write implements io.Writer
+func (b *FileBackedBuffer) Write(p []byte) (int, error) {
+	if b.reader != nil {
+		return 0, ErrWriteAfterRead
+	}
+
+	var n int
+	var err error
+
+	if b.file != nil {
+		n, err = b.file.Write(p)
+	} else {
+		if b.size+int64(len(p)) > b.maxMemorySize {
+			b.file, err = os.CreateTemp("", "gitea-buffer-")
+			if err != nil {
+				return 0, err
+			}
+
+			_, err = io.Copy(b.file, &b.buffer)
+			if err != nil {
+				return 0, err
+			}
+
+			return b.Write(p)
+		}
+
+		n, err = b.buffer.Write(p)
+	}
+
+	if err != nil {
+		return n, err
+	}
+	b.size += int64(n)
+	return n, nil
+}
+
+// Size returns the byte size of the buffered data
+func (b *FileBackedBuffer) Size() int64 {
+	return b.size
+}
+
+func (b *FileBackedBuffer) switchToReader() error {
+	if b.reader != nil {
+		return nil
+	}
+
+	if b.file != nil {
+		if _, err := b.file.Seek(0, io.SeekStart); err != nil {
+			return err
+		}
+		b.reader = b.file
+	} else {
+		b.reader = bytes.NewReader(b.buffer.Bytes())
+	}
+	return nil
+}
+
+// Read implements io.Reader
+func (b *FileBackedBuffer) Read(p []byte) (int, error) {
+	if err := b.switchToReader(); err != nil {
+		return 0, err
+	}
+
+	return b.reader.Read(p)
+}
+
+// ReadAt implements io.ReaderAt
+func (b *FileBackedBuffer) ReadAt(p []byte, off int64) (int, error) {
+	if err := b.switchToReader(); err != nil {
+		return 0, err
+	}
+
+	return b.reader.ReadAt(p, off)
+}
+
+// Seek implements io.Seeker
+func (b *FileBackedBuffer) Seek(offset int64, whence int) (int64, error) {
+	if err := b.switchToReader(); err != nil {
+		return 0, err
+	}
+
+	return b.reader.Seek(offset, whence)
+}
+
+// Close implements io.Closer
+func (b *FileBackedBuffer) Close() error {
+	if b.file != nil {
+		err := b.file.Close()
+		os.Remove(b.file.Name())
+		b.file = nil
+		return err
+	}
+	return nil
+}
diff --git a/modules/util/filebuffer/file_backed_buffer_test.go b/modules/util/filebuffer/file_backed_buffer_test.go
new file mode 100644
index 0000000..c56c1c6
--- /dev/null
+++ b/modules/util/filebuffer/file_backed_buffer_test.go
@@ -0,0 +1,36 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package filebuffer
+
+import (
+	"io"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestFileBackedBuffer(t *testing.T) {
+	cases := []struct {
+		MaxMemorySize int
+		Data          string
+	}{
+		{5, "test"},
+		{5, "testtest"},
+	}
+
+	for _, c := range cases {
+		buf, err := CreateFromReader(strings.NewReader(c.Data), c.MaxMemorySize)
+		require.NoError(t, err)
+
+		assert.EqualValues(t, len(c.Data), buf.Size())
+
+		data, err := io.ReadAll(buf)
+		require.NoError(t, err)
+		assert.Equal(t, c.Data, string(data))
+
+		require.NoError(t, buf.Close())
+	}
+}
diff --git a/modules/util/io.go b/modules/util/io.go
new file mode 100644
index 0000000..1559b01
--- /dev/null
+++ b/modules/util/io.go
@@ -0,0 +1,78 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"bytes"
+	"errors"
+	"io"
+)
+
+// ReadAtMost reads at most len(buf) bytes from r into buf.
+// It returns the number of bytes copied. n is only less than len(buf) if r provides fewer bytes.
+// If EOF or ErrUnexpectedEOF occurs while reading, err will be nil.
+func ReadAtMost(r io.Reader, buf []byte) (n int, err error) {
+	n, err = io.ReadFull(r, buf)
+	if err == io.EOF || err == io.ErrUnexpectedEOF {
+		err = nil
+	}
+	return n, err
+}
+
+// ReadWithLimit reads at most "limit" bytes from r into buf.
+// If EOF or ErrUnexpectedEOF occurs while reading, err will be nil.
+func ReadWithLimit(r io.Reader, n int) (buf []byte, err error) {
+	return readWithLimit(r, 1024, n)
+}
+
+func readWithLimit(r io.Reader, batch, limit int) ([]byte, error) {
+	if limit <= batch {
+		buf := make([]byte, limit)
+		n, err := ReadAtMost(r, buf)
+		if err != nil {
+			return nil, err
+		}
+		return buf[:n], nil
+	}
+	res := bytes.NewBuffer(make([]byte, 0, batch))
+	bufFix := make([]byte, batch)
+	eof := false
+	for res.Len() < limit && !eof {
+		bufTmp := bufFix
+		if res.Len()+batch > limit {
+			bufTmp = bufFix[:limit-res.Len()]
+		}
+		n, err := io.ReadFull(r, bufTmp)
+		if err == io.EOF || err == io.ErrUnexpectedEOF {
+			eof = true
+		} else if err != nil {
+			return nil, err
+		}
+		if _, err = res.Write(bufTmp[:n]); err != nil {
+			return nil, err
+		}
+	}
+	return res.Bytes(), nil
+}
+
+// ErrNotEmpty is an error reported when there is a non-empty reader
+var ErrNotEmpty = errors.New("not-empty")
+
+// IsEmptyReader reads a reader and ensures it is empty
+func IsEmptyReader(r io.Reader) (err error) {
+	var buf [1]byte
+
+	for {
+		n, err := r.Read(buf[:])
+		if err != nil {
+			if err == io.EOF {
+				return nil
+			}
+			return err
+		}
+		if n > 0 {
+			return ErrNotEmpty
+		}
+	}
+}
diff --git a/modules/util/io_test.go b/modules/util/io_test.go
new file mode 100644
index 0000000..870e713
--- /dev/null
+++ b/modules/util/io_test.go
@@ -0,0 +1,67 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"bytes"
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type readerWithError struct {
+	buf *bytes.Buffer
+}
+
+func (r *readerWithError) Read(p []byte) (n int, err error) {
+	if r.buf.Len() < 2 {
+		return 0, errors.New("test error")
+	}
+	return r.buf.Read(p)
+}
+
+func TestReadWithLimit(t *testing.T) {
+	bs := []byte("0123456789abcdef")
+
+	// normal test
+	buf, err := readWithLimit(bytes.NewBuffer(bs), 5, 2)
+	require.NoError(t, err)
+	assert.Equal(t, []byte("01"), buf)
+
+	buf, err = readWithLimit(bytes.NewBuffer(bs), 5, 5)
+	require.NoError(t, err)
+	assert.Equal(t, []byte("01234"), buf)
+
+	buf, err = readWithLimit(bytes.NewBuffer(bs), 5, 6)
+	require.NoError(t, err)
+	assert.Equal(t, []byte("012345"), buf)
+
+	buf, err = readWithLimit(bytes.NewBuffer(bs), 5, len(bs))
+	require.NoError(t, err)
+	assert.Equal(t, []byte("0123456789abcdef"), buf)
+
+	buf, err = readWithLimit(bytes.NewBuffer(bs), 5, 100)
+	require.NoError(t, err)
+	assert.Equal(t, []byte("0123456789abcdef"), buf)
+
+	// test with error
+	buf, err = readWithLimit(&readerWithError{bytes.NewBuffer(bs)}, 5, 10)
+	require.NoError(t, err)
+	assert.Equal(t, []byte("0123456789"), buf)
+
+	buf, err = readWithLimit(&readerWithError{bytes.NewBuffer(bs)}, 5, 100)
+	require.ErrorContains(t, err, "test error")
+	assert.Empty(t, buf)
+
+	// test public function
+	buf, err = ReadWithLimit(bytes.NewBuffer(bs), 2)
+	require.NoError(t, err)
+	assert.Equal(t, []byte("01"), buf)
+
+	buf, err = ReadWithLimit(bytes.NewBuffer(bs), 9999999)
+	require.NoError(t, err)
+	assert.Equal(t, []byte("0123456789abcdef"), buf)
+}
diff --git a/modules/util/keypair.go b/modules/util/keypair.go
new file mode 100644
index 0000000..07f27bd
--- /dev/null
+++ b/modules/util/keypair.go
@@ -0,0 +1,57 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/pem"
+)
+
+// GenerateKeyPair generates a public and private keypair
+func GenerateKeyPair(bits int) (string, string, error) {
+	priv, _ := rsa.GenerateKey(rand.Reader, bits)
+	privPem := pemBlockForPriv(priv)
+	pubPem, err := pemBlockForPub(&priv.PublicKey)
+	if err != nil {
+		return "", "", err
+	}
+	return privPem, pubPem, nil
+}
+
+func pemBlockForPriv(priv *rsa.PrivateKey) string {
+	privBytes := pem.EncodeToMemory(&pem.Block{
+		Type:  "RSA PRIVATE KEY",
+		Bytes: x509.MarshalPKCS1PrivateKey(priv),
+	})
+	return string(privBytes)
+}
+
+func pemBlockForPub(pub *rsa.PublicKey) (string, error) {
+	pubASN1, err := x509.MarshalPKIXPublicKey(pub)
+	if err != nil {
+		return "", err
+	}
+	pubBytes := pem.EncodeToMemory(&pem.Block{
+		Type:  "PUBLIC KEY",
+		Bytes: pubASN1,
+	})
+	return string(pubBytes), nil
+}
+
+// CreatePublicKeyFingerprint creates a fingerprint of the given key.
+// The fingerprint is the sha256 sum of the PKIX structure of the key.
+func CreatePublicKeyFingerprint(key crypto.PublicKey) ([]byte, error) {
+	bytes, err := x509.MarshalPKIXPublicKey(key)
+	if err != nil {
+		return nil, err
+	}
+
+	checksum := sha256.Sum256(bytes)
+
+	return checksum[:], nil
+}
diff --git a/modules/util/keypair_test.go b/modules/util/keypair_test.go
new file mode 100644
index 0000000..ec9bca7
--- /dev/null
+++ b/modules/util/keypair_test.go
@@ -0,0 +1,62 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/pem"
+	"regexp"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestKeygen(t *testing.T) {
+	priv, pub, err := GenerateKeyPair(2048)
+	require.NoError(t, err)
+
+	assert.NotEmpty(t, priv)
+	assert.NotEmpty(t, pub)
+
+	assert.Regexp(t, regexp.MustCompile("^-----BEGIN RSA PRIVATE KEY-----.*"), priv)
+	assert.Regexp(t, regexp.MustCompile("^-----BEGIN PUBLIC KEY-----.*"), pub)
+}
+
+func TestSignUsingKeys(t *testing.T) {
+	priv, pub, err := GenerateKeyPair(2048)
+	require.NoError(t, err)
+
+	privPem, _ := pem.Decode([]byte(priv))
+	if privPem == nil || privPem.Type != "RSA PRIVATE KEY" {
+		t.Fatal("key is wrong type")
+	}
+
+	privParsed, err := x509.ParsePKCS1PrivateKey(privPem.Bytes)
+	require.NoError(t, err)
+
+	pubPem, _ := pem.Decode([]byte(pub))
+	if pubPem == nil || pubPem.Type != "PUBLIC KEY" {
+		t.Fatal("key failed to decode")
+	}
+
+	pubParsed, err := x509.ParsePKIXPublicKey(pubPem.Bytes)
+	require.NoError(t, err)
+
+	// Sign
+	msg := "activity pub is great!"
+	h := sha256.New()
+	h.Write([]byte(msg))
+	d := h.Sum(nil)
+	sig, err := rsa.SignPKCS1v15(rand.Reader, privParsed, crypto.SHA256, d)
+	require.NoError(t, err)
+
+	// Verify
+	err = rsa.VerifyPKCS1v15(pubParsed.(*rsa.PublicKey), crypto.SHA256, d, sig)
+	require.NoError(t, err)
+}
diff --git a/modules/util/legacy.go b/modules/util/legacy.go
new file mode 100644
index 0000000..2d4de01
--- /dev/null
+++ b/modules/util/legacy.go
@@ -0,0 +1,38 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"io"
+	"os"
+)
+
+// CopyFile copies file from source to target path.
+func CopyFile(src, dest string) error {
+	si, err := os.Lstat(src)
+	if err != nil {
+		return err
+	}
+
+	sr, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer sr.Close()
+
+	dw, err := os.Create(dest)
+	if err != nil {
+		return err
+	}
+	defer dw.Close()
+
+	if _, err = io.Copy(dw, sr); err != nil {
+		return err
+	}
+
+	if err = os.Chtimes(dest, si.ModTime(), si.ModTime()); err != nil {
+		return err
+	}
+	return os.Chmod(dest, si.Mode())
+}
diff --git a/modules/util/legacy_test.go b/modules/util/legacy_test.go
new file mode 100644
index 0000000..62c2f8a
--- /dev/null
+++ b/modules/util/legacy_test.go
@@ -0,0 +1,38 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"fmt"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCopyFile(t *testing.T) {
+	testContent := []byte("hello")
+
+	tmpDir := os.TempDir()
+	now := time.Now()
+	srcFile := fmt.Sprintf("%s/copy-test-%d-src.txt", tmpDir, now.UnixMicro())
+	dstFile := fmt.Sprintf("%s/copy-test-%d-dst.txt", tmpDir, now.UnixMicro())
+
+	_ = os.Remove(srcFile)
+	_ = os.Remove(dstFile)
+	defer func() {
+		_ = os.Remove(srcFile)
+		_ = os.Remove(dstFile)
+	}()
+
+	err := os.WriteFile(srcFile, testContent, 0o777)
+	require.NoError(t, err)
+	err = CopyFile(srcFile, dstFile)
+	require.NoError(t, err)
+	dstContent, err := os.ReadFile(dstFile)
+	require.NoError(t, err)
+	assert.Equal(t, testContent, dstContent)
+}
diff --git a/modules/util/pack.go b/modules/util/pack.go
new file mode 100644
index 0000000..7fc074a
--- /dev/null
+++ b/modules/util/pack.go
@@ -0,0 +1,33 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"bytes"
+	"encoding/gob"
+)
+
+// PackData uses gob to encode the given data in sequence
+func PackData(data ...any) ([]byte, error) {
+	var buf bytes.Buffer
+	enc := gob.NewEncoder(&buf)
+	for _, datum := range data {
+		if err := enc.Encode(datum); err != nil {
+			return nil, err
+		}
+	}
+	return buf.Bytes(), nil
+}
+
+// UnpackData uses gob to decode the given data in sequence
+func UnpackData(buf []byte, data ...any) error {
+	r := bytes.NewReader(buf)
+	enc := gob.NewDecoder(r)
+	for _, datum := range data {
+		if err := enc.Decode(datum); err != nil {
+			return err
+		}
+	}
+	return nil
+}
diff --git a/modules/util/pack_test.go b/modules/util/pack_test.go
new file mode 100644
index 0000000..42ada89
--- /dev/null
+++ b/modules/util/pack_test.go
@@ -0,0 +1,28 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPackAndUnpackData(t *testing.T) {
+	s := "string"
+	i := int64(4)
+	f := float32(4.1)
+
+	var s2 string
+	var i2 int64
+	var f2 float32
+
+	data, err := PackData(s, i, f)
+	require.NoError(t, err)
+
+	require.NoError(t, UnpackData(data, &s2, &i2, &f2))
+	require.NoError(t, UnpackData(data, &s2))
+	require.Error(t, UnpackData(data, &i2))
+	require.Error(t, UnpackData(data, &s2, &f2))
+}
diff --git a/modules/util/paginate.go b/modules/util/paginate.go
new file mode 100644
index 0000000..87f31b7
--- /dev/null
+++ b/modules/util/paginate.go
@@ -0,0 +1,33 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import "reflect"
+
+// PaginateSlice cut a slice as per pagination options
+// if page = 0 it do not paginate
+func PaginateSlice(list any, page, pageSize int) any {
+	if page <= 0 || pageSize <= 0 {
+		return list
+	}
+	if reflect.TypeOf(list).Kind() != reflect.Slice {
+		return list
+	}
+
+	listValue := reflect.ValueOf(list)
+
+	page--
+
+	if page*pageSize >= listValue.Len() {
+		return listValue.Slice(listValue.Len(), listValue.Len()).Interface()
+	}
+
+	listValue = listValue.Slice(page*pageSize, listValue.Len())
+
+	if listValue.Len() > pageSize {
+		return listValue.Slice(0, pageSize).Interface()
+	}
+
+	return listValue.Interface()
+}
diff --git a/modules/util/paginate_test.go b/modules/util/paginate_test.go
new file mode 100644
index 0000000..6e69dd1
--- /dev/null
+++ b/modules/util/paginate_test.go
@@ -0,0 +1,46 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPaginateSlice(t *testing.T) {
+	stringSlice := []string{"a", "b", "c", "d", "e"}
+	result, ok := PaginateSlice(stringSlice, 1, 2).([]string)
+	assert.True(t, ok)
+	assert.EqualValues(t, []string{"a", "b"}, result)
+
+	result, ok = PaginateSlice(stringSlice, 100, 2).([]string)
+	assert.True(t, ok)
+	assert.EqualValues(t, []string{}, result)
+
+	result, ok = PaginateSlice(stringSlice, 3, 2).([]string)
+	assert.True(t, ok)
+	assert.EqualValues(t, []string{"e"}, result)
+
+	result, ok = PaginateSlice(stringSlice, 1, 0).([]string)
+	assert.True(t, ok)
+	assert.EqualValues(t, []string{"a", "b", "c", "d", "e"}, result)
+
+	result, ok = PaginateSlice(stringSlice, 1, -1).([]string)
+	assert.True(t, ok)
+	assert.EqualValues(t, []string{"a", "b", "c", "d", "e"}, result)
+
+	type Test struct {
+		Val int
+	}
+
+	testVar := []*Test{{Val: 2}, {Val: 3}, {Val: 4}}
+	testVar, ok = PaginateSlice(testVar, 1, 50).([]*Test)
+	assert.True(t, ok)
+	assert.EqualValues(t, []*Test{{Val: 2}, {Val: 3}, {Val: 4}}, testVar)
+
+	testVar, ok = PaginateSlice(testVar, 2, 2).([]*Test)
+	assert.True(t, ok)
+	assert.EqualValues(t, []*Test{{Val: 4}}, testVar)
+}
diff --git a/modules/util/path.go b/modules/util/path.go
new file mode 100644
index 0000000..185e7cf
--- /dev/null
+++ b/modules/util/path.go
@@ -0,0 +1,322 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"errors"
+	"fmt"
+	"net/url"
+	"os"
+	"path"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"strings"
+)
+
+// PathJoinRel joins the path elements into a single path, each element is cleaned by path.Clean separately.
+// It only returns the following values (like path.Join), any redundant part (empty, relative dots, slashes) is removed.
+// It's caller's duty to make every element not bypass its own directly level, to avoid security issues.
+//
+//	empty => ``
+//	`` => ``
+//	`..` => `.`
+//	`dir` => `dir`
+//	`/dir/` => `dir`
+//	`foo\..\bar` => `foo\..\bar`
+//	{`foo`, ``, `bar`} => `foo/bar`
+//	{`foo`, `..`, `bar`} => `foo/bar`
+func PathJoinRel(elem ...string) string {
+	elems := make([]string, len(elem))
+	for i, e := range elem {
+		if e == "" {
+			continue
+		}
+		elems[i] = path.Clean("/" + e)
+	}
+	p := path.Join(elems...)
+	if p == "" {
+		return ""
+	} else if p == "/" {
+		return "."
+	}
+	return p[1:]
+}
+
+// PathJoinRelX joins the path elements into a single path like PathJoinRel,
+// and convert all backslashes to slashes. (X means "extended", also means the combination of `\` and `/`).
+// It's caller's duty to make every element not bypass its own directly level, to avoid security issues.
+// It returns similar results as PathJoinRel except:
+//
+//	`foo\..\bar` => `bar`  (because it's processed as `foo/../bar`)
+//
+// All backslashes are handled as slashes, the result only contains slashes.
+func PathJoinRelX(elem ...string) string {
+	elems := make([]string, len(elem))
+	for i, e := range elem {
+		if e == "" {
+			continue
+		}
+		elems[i] = path.Clean("/" + strings.ReplaceAll(e, "\\", "/"))
+	}
+	return PathJoinRel(elems...)
+}
+
+const pathSeparator = string(os.PathSeparator)
+
+// FilePathJoinAbs joins the path elements into a single file path, each element is cleaned by filepath.Clean separately.
+// All slashes/backslashes are converted to path separators before cleaning, the result only contains path separators.
+// The first element must be an absolute path, caller should prepare the base path.
+// It's caller's duty to make every element not bypass its own directly level, to avoid security issues.
+// Like PathJoinRel, any redundant part (empty, relative dots, slashes) is removed.
+//
+//	{`/foo`, ``, `bar`} => `/foo/bar`
+//	{`/foo`, `..`, `bar`} => `/foo/bar`
+func FilePathJoinAbs(base string, sub ...string) string {
+	elems := make([]string, 1, len(sub)+1)
+
+	// POSIX filesystem can have `\` in file names. Windows: `\` and `/` are both used for path separators
+	// to keep the behavior consistent, we do not allow `\` in file names, replace all `\` with `/`
+	if isOSWindows() {
+		elems[0] = filepath.Clean(base)
+	} else {
+		elems[0] = filepath.Clean(strings.ReplaceAll(base, "\\", pathSeparator))
+	}
+	if !filepath.IsAbs(elems[0]) {
+		// This shouldn't happen. If there is really necessary to pass in relative path, return the full path with filepath.Abs() instead
+		panic(fmt.Sprintf("FilePathJoinAbs: %q (for path %v) is not absolute, do not guess a relative path based on current working directory", elems[0], elems))
+	}
+	for _, s := range sub {
+		if s == "" {
+			continue
+		}
+		if isOSWindows() {
+			elems = append(elems, filepath.Clean(pathSeparator+s))
+		} else {
+			elems = append(elems, filepath.Clean(pathSeparator+strings.ReplaceAll(s, "\\", pathSeparator)))
+		}
+	}
+	// the elems[0] must be an absolute path, just join them together
+	return filepath.Join(elems...)
+}
+
+// IsDir returns true if given path is a directory,
+// or returns false when it's a file or does not exist.
+func IsDir(dir string) (bool, error) {
+	f, err := os.Stat(dir)
+	if err == nil {
+		return f.IsDir(), nil
+	}
+	if os.IsNotExist(err) {
+		return false, nil
+	}
+	return false, err
+}
+
+// IsFile returns true if given path is a file,
+// or returns false when it's a directory or does not exist.
+func IsFile(filePath string) (bool, error) {
+	f, err := os.Stat(filePath)
+	if err == nil {
+		return !f.IsDir(), nil
+	}
+	if os.IsNotExist(err) {
+		return false, nil
+	}
+	return false, err
+}
+
+// IsExist checks whether a file or directory exists.
+// It returns false when the file or directory does not exist.
+func IsExist(path string) (bool, error) {
+	_, err := os.Stat(path)
+	if err == nil || os.IsExist(err) {
+		return true, nil
+	}
+	if os.IsNotExist(err) {
+		return false, nil
+	}
+	return false, err
+}
+
+func statDir(dirPath, recPath string, includeDir, isDirOnly, followSymlinks bool) ([]string, error) {
+	dir, err := os.Open(dirPath)
+	if err != nil {
+		return nil, err
+	}
+	defer dir.Close()
+
+	fis, err := dir.Readdir(0)
+	if err != nil {
+		return nil, err
+	}
+
+	statList := make([]string, 0)
+	for _, fi := range fis {
+		if CommonSkip(fi.Name()) {
+			continue
+		}
+
+		relPath := path.Join(recPath, fi.Name())
+		curPath := path.Join(dirPath, fi.Name())
+		if fi.IsDir() {
+			if includeDir {
+				statList = append(statList, relPath+"/")
+			}
+			s, err := statDir(curPath, relPath, includeDir, isDirOnly, followSymlinks)
+			if err != nil {
+				return nil, err
+			}
+			statList = append(statList, s...)
+		} else if !isDirOnly {
+			statList = append(statList, relPath)
+		} else if followSymlinks && fi.Mode()&os.ModeSymlink != 0 {
+			link, err := os.Readlink(curPath)
+			if err != nil {
+				return nil, err
+			}
+
+			isDir, err := IsDir(link)
+			if err != nil {
+				return nil, err
+			}
+			if isDir {
+				if includeDir {
+					statList = append(statList, relPath+"/")
+				}
+				s, err := statDir(curPath, relPath, includeDir, isDirOnly, followSymlinks)
+				if err != nil {
+					return nil, err
+				}
+				statList = append(statList, s...)
+			}
+		}
+	}
+	return statList, nil
+}
+
+// StatDir gathers information of given directory by depth-first.
+// It returns slice of file list and includes subdirectories if enabled;
+// it returns error and nil slice when error occurs in underlying functions,
+// or given path is not a directory or does not exist.
+//
+// Slice does not include given path itself.
+// If subdirectories is enabled, they will have suffix '/'.
+func StatDir(rootPath string, includeDir ...bool) ([]string, error) {
+	if isDir, err := IsDir(rootPath); err != nil {
+		return nil, err
+	} else if !isDir {
+		return nil, errors.New("not a directory or does not exist: " + rootPath)
+	}
+
+	isIncludeDir := false
+	if len(includeDir) != 0 {
+		isIncludeDir = includeDir[0]
+	}
+	return statDir(rootPath, "", isIncludeDir, false, false)
+}
+
+func isOSWindows() bool {
+	return runtime.GOOS == "windows"
+}
+
+var driveLetterRegexp = regexp.MustCompile("/[A-Za-z]:/")
+
+// FileURLToPath extracts the path information from a file://... url.
+// It returns an error only if the URL is not a file URL.
+func FileURLToPath(u *url.URL) (string, error) {
+	if u.Scheme != "file" {
+		return "", errors.New("URL scheme is not 'file': " + u.String())
+	}
+
+	path := u.Path
+
+	if !isOSWindows() {
+		return path, nil
+	}
+
+	// If it looks like there's a Windows drive letter at the beginning, strip off the leading slash.
+	if driveLetterRegexp.MatchString(path) {
+		return path[1:], nil
+	}
+	return path, nil
+}
+
+// HomeDir returns path of '~'(in Linux) on Windows,
+// it returns error when the variable does not exist.
+func HomeDir() (home string, err error) {
+	// TODO: some users run Gitea with mismatched uid  and "HOME=xxx" (they set HOME=xxx by environment manually)
+	// TODO: when running gitea as a sub command inside git, the HOME directory is not the user's home directory
+	// so at the moment we can not use `user.Current().HomeDir`
+	if isOSWindows() {
+		home = os.Getenv("USERPROFILE")
+		if home == "" {
+			home = os.Getenv("HOMEDRIVE") + os.Getenv("HOMEPATH")
+		}
+	} else {
+		home = os.Getenv("HOME")
+	}
+
+	if home == "" {
+		return "", errors.New("cannot get home directory")
+	}
+
+	return home, nil
+}
+
+// CommonSkip will check a provided name to see if it represents file or directory that should not be watched
+func CommonSkip(name string) bool {
+	if name == "" {
+		return true
+	}
+
+	switch name[0] {
+	case '.':
+		return true
+	case 't', 'T':
+		return name[1:] == "humbs.db"
+	case 'd', 'D':
+		return name[1:] == "esktop.ini"
+	}
+
+	return false
+}
+
+// IsReadmeFileName reports whether name looks like a README file
+// based on its name.
+func IsReadmeFileName(name string) bool {
+	name = strings.ToLower(name)
+	if len(name) < 6 {
+		return false
+	} else if len(name) == 6 {
+		return name == "readme"
+	}
+	return name[:7] == "readme."
+}
+
+// IsReadmeFileExtension reports whether name looks like a README file
+// based on its name. It will look through the provided extensions and check if the file matches
+// one of the extensions and provide the index in the extension list.
+// If the filename is `readme.` with an unmatched extension it will match with the index equaling
+// the length of the provided extension list.
+// Note that the '.' should be provided in ext, e.g ".md"
+func IsReadmeFileExtension(name string, ext ...string) (int, bool) {
+	name = strings.ToLower(name)
+	if len(name) < 6 || name[:6] != "readme" {
+		return 0, false
+	}
+
+	for i, extension := range ext {
+		extension = strings.ToLower(extension)
+		if name[6:] == extension {
+			return i, true
+		}
+	}
+
+	if name[6] == '.' {
+		return len(ext), true
+	}
+
+	return 0, false
+}
diff --git a/modules/util/path_test.go b/modules/util/path_test.go
new file mode 100644
index 0000000..3699f05
--- /dev/null
+++ b/modules/util/path_test.go
@@ -0,0 +1,213 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"net/url"
+	"runtime"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestFileURLToPath(t *testing.T) {
+	cases := []struct {
+		url      string
+		expected string
+		haserror bool
+		windows  bool
+	}{
+		// case 0
+		{
+			url:      "",
+			haserror: true,
+		},
+		// case 1
+		{
+			url:      "http://test.io",
+			haserror: true,
+		},
+		// case 2
+		{
+			url:      "file:///path",
+			expected: "/path",
+		},
+		// case 3
+		{
+			url:      "file:///C:/path",
+			expected: "C:/path",
+			windows:  true,
+		},
+	}
+
+	for n, c := range cases {
+		if c.windows && runtime.GOOS != "windows" {
+			continue
+		}
+		u, _ := url.Parse(c.url)
+		p, err := FileURLToPath(u)
+		if c.haserror {
+			require.Error(t, err, "case %d: should return error", n)
+		} else {
+			require.NoError(t, err, "case %d: should not return error", n)
+			assert.Equal(t, c.expected, p, "case %d: should be equal", n)
+		}
+	}
+}
+
+func TestMisc_IsReadmeFileName(t *testing.T) {
+	trueTestCases := []string{
+		"readme",
+		"README",
+		"readME.mdown",
+		"README.md",
+		"readme.i18n.md",
+	}
+	falseTestCases := []string{
+		"test.md",
+		"wow.MARKDOWN",
+		"LOL.mDoWn",
+		"test",
+		"abcdefg",
+		"abcdefghijklmnopqrstuvwxyz",
+		"test.md.test",
+		"readmf",
+	}
+
+	for _, testCase := range trueTestCases {
+		assert.True(t, IsReadmeFileName(testCase))
+	}
+	for _, testCase := range falseTestCases {
+		assert.False(t, IsReadmeFileName(testCase))
+	}
+
+	type extensionTestcase struct {
+		name     string
+		expected bool
+		idx      int
+	}
+
+	exts := []string{".md", ".txt", ""}
+	testCasesExtensions := []extensionTestcase{
+		{
+			name:     "readme",
+			expected: true,
+			idx:      2,
+		},
+		{
+			name:     "readme.md",
+			expected: true,
+			idx:      0,
+		},
+		{
+			name:     "README.md",
+			expected: true,
+			idx:      0,
+		},
+		{
+			name:     "ReAdMe.Md",
+			expected: true,
+			idx:      0,
+		},
+		{
+			name:     "readme.txt",
+			expected: true,
+			idx:      1,
+		},
+		{
+			name:     "readme.doc",
+			expected: true,
+			idx:      3,
+		},
+		{
+			name: "readmee.md",
+		},
+		{
+			name:     "readme..",
+			expected: true,
+			idx:      3,
+		},
+	}
+
+	for _, testCase := range testCasesExtensions {
+		idx, ok := IsReadmeFileExtension(testCase.name, exts...)
+		assert.Equal(t, testCase.expected, ok)
+		assert.Equal(t, testCase.idx, idx)
+	}
+}
+
+func TestCleanPath(t *testing.T) {
+	cases := []struct {
+		elems    []string
+		expected string
+	}{
+		{[]string{}, ``},
+		{[]string{``}, ``},
+		{[]string{`..`}, `.`},
+		{[]string{`a`}, `a`},
+		{[]string{`/a/`}, `a`},
+		{[]string{`../a/`, `../b`, `c/..`, `d`}, `a/b/d`},
+		{[]string{`a\..\b`}, `a\..\b`},
+		{[]string{`a`, ``, `b`}, `a/b`},
+		{[]string{`a`, `..`, `b`}, `a/b`},
+		{[]string{`lfs`, `repo/..`, `user/../path`}, `lfs/path`},
+	}
+	for _, c := range cases {
+		assert.Equal(t, c.expected, PathJoinRel(c.elems...), "case: %v", c.elems)
+	}
+
+	cases = []struct {
+		elems    []string
+		expected string
+	}{
+		{[]string{}, ``},
+		{[]string{``}, ``},
+		{[]string{`..`}, `.`},
+		{[]string{`a`}, `a`},
+		{[]string{`/a/`}, `a`},
+		{[]string{`../a/`, `../b`, `c/..`, `d`}, `a/b/d`},
+		{[]string{`a\..\b`}, `b`},
+		{[]string{`a`, ``, `b`}, `a/b`},
+		{[]string{`a`, `..`, `b`}, `a/b`},
+		{[]string{`lfs`, `repo/..`, `user/../path`}, `lfs/path`},
+	}
+	for _, c := range cases {
+		assert.Equal(t, c.expected, PathJoinRelX(c.elems...), "case: %v", c.elems)
+	}
+
+	// for POSIX only, but the result is similar on Windows, because the first element must be an absolute path
+	if isOSWindows() {
+		cases = []struct {
+			elems    []string
+			expected string
+		}{
+			{[]string{`C:\..`}, `C:\`},
+			{[]string{`C:\a`}, `C:\a`},
+			{[]string{`C:\a/`}, `C:\a`},
+			{[]string{`C:\..\a\`, `../b`, `c\..`, `d`}, `C:\a\b\d`},
+			{[]string{`C:\a/..\b`}, `C:\b`},
+			{[]string{`C:\a`, ``, `b`}, `C:\a\b`},
+			{[]string{`C:\a`, `..`, `b`}, `C:\a\b`},
+			{[]string{`C:\lfs`, `repo/..`, `user/../path`}, `C:\lfs\path`},
+		}
+	} else {
+		cases = []struct {
+			elems    []string
+			expected string
+		}{
+			{[]string{`/..`}, `/`},
+			{[]string{`/a`}, `/a`},
+			{[]string{`/a/`}, `/a`},
+			{[]string{`/../a/`, `../b`, `c/..`, `d`}, `/a/b/d`},
+			{[]string{`/a\..\b`}, `/b`},
+			{[]string{`/a`, ``, `b`}, `/a/b`},
+			{[]string{`/a`, `..`, `b`}, `/a/b`},
+			{[]string{`/lfs`, `repo/..`, `user/../path`}, `/lfs/path`},
+		}
+	}
+	for _, c := range cases {
+		assert.Equal(t, c.expected, FilePathJoinAbs(c.elems[0], c.elems[1:]...), "case: %v", c.elems)
+	}
+}
diff --git a/modules/util/remove.go b/modules/util/remove.go
new file mode 100644
index 0000000..d1e38fa
--- /dev/null
+++ b/modules/util/remove.go
@@ -0,0 +1,104 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"os"
+	"runtime"
+	"syscall"
+	"time"
+)
+
+const windowsSharingViolationError syscall.Errno = 32
+
+// Remove removes the named file or (empty) directory with at most 5 attempts.
+func Remove(name string) error {
+	var err error
+	for i := 0; i < 5; i++ {
+		err = os.Remove(name)
+		if err == nil {
+			break
+		}
+		unwrapped := err.(*os.PathError).Err
+		if unwrapped == syscall.EBUSY || unwrapped == syscall.ENOTEMPTY || unwrapped == syscall.EPERM || unwrapped == syscall.EMFILE || unwrapped == syscall.ENFILE {
+			// try again
+			<-time.After(100 * time.Millisecond)
+			continue
+		}
+
+		if unwrapped == windowsSharingViolationError && runtime.GOOS == "windows" {
+			// try again
+			<-time.After(100 * time.Millisecond)
+			continue
+		}
+
+		if unwrapped == syscall.ENOENT {
+			// it's already gone
+			return nil
+		}
+	}
+	return err
+}
+
+// RemoveAll removes the named file or (empty) directory with at most 5 attempts.
+func RemoveAll(name string) error {
+	var err error
+	for i := 0; i < 5; i++ {
+		err = os.RemoveAll(name)
+		if err == nil {
+			break
+		}
+		unwrapped := err.(*os.PathError).Err
+		if unwrapped == syscall.EBUSY || unwrapped == syscall.ENOTEMPTY || unwrapped == syscall.EPERM || unwrapped == syscall.EMFILE || unwrapped == syscall.ENFILE {
+			// try again
+			<-time.After(100 * time.Millisecond)
+			continue
+		}
+
+		if unwrapped == windowsSharingViolationError && runtime.GOOS == "windows" {
+			// try again
+			<-time.After(100 * time.Millisecond)
+			continue
+		}
+
+		if unwrapped == syscall.ENOENT {
+			// it's already gone
+			return nil
+		}
+	}
+	return err
+}
+
+// Rename renames (moves) oldpath to newpath with at most 5 attempts.
+func Rename(oldpath, newpath string) error {
+	var err error
+	for i := 0; i < 5; i++ {
+		err = os.Rename(oldpath, newpath)
+		if err == nil {
+			break
+		}
+		unwrapped := err.(*os.LinkError).Err
+		if unwrapped == syscall.EBUSY || unwrapped == syscall.ENOTEMPTY || unwrapped == syscall.EPERM || unwrapped == syscall.EMFILE || unwrapped == syscall.ENFILE {
+			// try again
+			<-time.After(100 * time.Millisecond)
+			continue
+		}
+
+		if unwrapped == windowsSharingViolationError && runtime.GOOS == "windows" {
+			// try again
+			<-time.After(100 * time.Millisecond)
+			continue
+		}
+
+		if i == 0 && os.IsNotExist(err) {
+			return err
+		}
+
+		if unwrapped == syscall.ENOENT {
+			// it's already gone
+			return nil
+		}
+	}
+	return err
+}
diff --git a/modules/util/rotatingfilewriter/writer.go b/modules/util/rotatingfilewriter/writer.go
new file mode 100644
index 0000000..c595f49
--- /dev/null
+++ b/modules/util/rotatingfilewriter/writer.go
@@ -0,0 +1,246 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package rotatingfilewriter
+
+import (
+	"bufio"
+	"compress/gzip"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+
+	"code.gitea.io/gitea/modules/graceful/releasereopen"
+	"code.gitea.io/gitea/modules/util"
+)
+
+type Options struct {
+	Rotate           bool
+	MaximumSize      int64
+	RotateDaily      bool
+	KeepDays         int
+	Compress         bool
+	CompressionLevel int
+}
+
+type RotatingFileWriter struct {
+	mu sync.Mutex
+	fd *os.File
+
+	currentSize int64
+	openDate    int
+
+	options Options
+
+	cancelReleaseReopen func()
+}
+
+var ErrorPrintf func(format string, args ...any)
+
+// errorf tries to print error messages. Since this writer could be used by a logger system, this is the last chance to show the error in some cases
+func errorf(format string, args ...any) {
+	if ErrorPrintf != nil {
+		ErrorPrintf("rotatingfilewriter: "+format+"\n", args...)
+	}
+}
+
+// Open creates a new rotating file writer.
+// Notice: if a file is opened by two rotators, there will be conflicts when rotating.
+// In the future, there should be "rotating file manager"
+func Open(filename string, options *Options) (*RotatingFileWriter, error) {
+	if options == nil {
+		options = &Options{}
+	}
+
+	rfw := &RotatingFileWriter{
+		options: *options,
+	}
+
+	if err := rfw.open(filename); err != nil {
+		return nil, err
+	}
+
+	rfw.cancelReleaseReopen = releasereopen.GetManager().Register(rfw)
+	return rfw, nil
+}
+
+func (rfw *RotatingFileWriter) Write(b []byte) (int, error) {
+	if rfw.options.Rotate && ((rfw.options.MaximumSize > 0 && rfw.currentSize >= rfw.options.MaximumSize) || (rfw.options.RotateDaily && time.Now().Day() != rfw.openDate)) {
+		if err := rfw.DoRotate(); err != nil {
+			// if this writer is used by a logger system, it's the logger system's responsibility to handle/show the error
+			return 0, err
+		}
+	}
+
+	n, err := rfw.fd.Write(b)
+	if err == nil {
+		rfw.currentSize += int64(n)
+	}
+	return n, err
+}
+
+func (rfw *RotatingFileWriter) Flush() error {
+	return rfw.fd.Sync()
+}
+
+func (rfw *RotatingFileWriter) Close() error {
+	rfw.mu.Lock()
+	if rfw.cancelReleaseReopen != nil {
+		rfw.cancelReleaseReopen()
+		rfw.cancelReleaseReopen = nil
+	}
+	rfw.mu.Unlock()
+	return rfw.fd.Close()
+}
+
+func (rfw *RotatingFileWriter) open(filename string) error {
+	fd, err := os.OpenFile(filename, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0o660)
+	if err != nil {
+		return err
+	}
+
+	rfw.fd = fd
+
+	finfo, err := fd.Stat()
+	if err != nil {
+		return err
+	}
+	rfw.currentSize = finfo.Size()
+	rfw.openDate = finfo.ModTime().Day()
+
+	return nil
+}
+
+func (rfw *RotatingFileWriter) ReleaseReopen() error {
+	return errors.Join(
+		rfw.fd.Close(),
+		rfw.open(rfw.fd.Name()),
+	)
+}
+
+// DoRotate the log file creating a backup like xx.2013-01-01.2
+func (rfw *RotatingFileWriter) DoRotate() error {
+	if !rfw.options.Rotate {
+		return nil
+	}
+
+	rfw.mu.Lock()
+	defer rfw.mu.Unlock()
+
+	prefix := fmt.Sprintf("%s.%s.", rfw.fd.Name(), time.Now().Format("2006-01-02"))
+
+	var err error
+	fname := ""
+	for i := 1; err == nil && i <= 999; i++ {
+		fname = prefix + fmt.Sprintf("%03d", i)
+		_, err = os.Lstat(fname)
+		if rfw.options.Compress && err != nil {
+			_, err = os.Lstat(fname + ".gz")
+		}
+	}
+	// return error if the last file checked still existed
+	if err == nil {
+		return fmt.Errorf("cannot find free file to rename %s", rfw.fd.Name())
+	}
+
+	fd := rfw.fd
+	if err := fd.Close(); err != nil { // close file before rename
+		return err
+	}
+
+	if err := util.Rename(fd.Name(), fname); err != nil {
+		return err
+	}
+
+	if rfw.options.Compress {
+		go func() {
+			err := compressOldFile(fname, rfw.options.CompressionLevel)
+			if err != nil {
+				errorf("DoRotate: %v", err)
+			}
+		}()
+	}
+
+	if err := rfw.open(fd.Name()); err != nil {
+		return err
+	}
+
+	go deleteOldFiles(
+		filepath.Dir(fd.Name()),
+		filepath.Base(fd.Name()),
+		time.Now().AddDate(0, 0, -rfw.options.KeepDays),
+	)
+
+	return nil
+}
+
+func compressOldFile(fname string, compressionLevel int) error {
+	reader, err := os.Open(fname)
+	if err != nil {
+		return fmt.Errorf("compressOldFile: failed to open existing file %s: %w", fname, err)
+	}
+	defer reader.Close()
+
+	buffer := bufio.NewReader(reader)
+	fnameGz := fname + ".gz"
+	fw, err := os.OpenFile(fnameGz, os.O_WRONLY|os.O_CREATE, 0o660)
+	if err != nil {
+		return fmt.Errorf("compressOldFile: failed to open new file %s: %w", fnameGz, err)
+	}
+	defer fw.Close()
+
+	zw, err := gzip.NewWriterLevel(fw, compressionLevel)
+	if err != nil {
+		return fmt.Errorf("compressOldFile: failed to create gzip writer: %w", err)
+	}
+	defer zw.Close()
+
+	_, err = buffer.WriteTo(zw)
+	if err != nil {
+		_ = zw.Close()
+		_ = fw.Close()
+		_ = util.Remove(fname + ".gz")
+		return fmt.Errorf("compressOldFile: failed to write to gz file: %w", err)
+	}
+	_ = reader.Close()
+
+	err = util.Remove(fname)
+	if err != nil {
+		return fmt.Errorf("compressOldFile: failed to delete old file: %w", err)
+	}
+	return nil
+}
+
+func deleteOldFiles(dir, prefix string, removeBefore time.Time) {
+	err := filepath.WalkDir(dir, func(path string, d os.DirEntry, err error) (returnErr error) {
+		defer func() {
+			if r := recover(); r != nil {
+				returnErr = fmt.Errorf("unable to delete old file '%s', error: %+v", path, r)
+			}
+		}()
+
+		if err != nil {
+			return err
+		}
+		if d.IsDir() {
+			return nil
+		}
+		info, err := d.Info()
+		if err != nil {
+			return err
+		}
+		if info.ModTime().Before(removeBefore) {
+			if strings.HasPrefix(filepath.Base(path), prefix) {
+				return util.Remove(path)
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		errorf("deleteOldFiles: failed to delete old file: %v", err)
+	}
+}
diff --git a/modules/util/rotatingfilewriter/writer_test.go b/modules/util/rotatingfilewriter/writer_test.go
new file mode 100644
index 0000000..5b3b351
--- /dev/null
+++ b/modules/util/rotatingfilewriter/writer_test.go
@@ -0,0 +1,49 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package rotatingfilewriter
+
+import (
+	"compress/gzip"
+	"io"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCompressOldFile(t *testing.T) {
+	tmpDir := t.TempDir()
+	fname := filepath.Join(tmpDir, "test")
+	nonGzip := filepath.Join(tmpDir, "test-nonGzip")
+
+	f, err := os.OpenFile(fname, os.O_CREATE|os.O_WRONLY, 0o660)
+	require.NoError(t, err)
+	ng, err := os.OpenFile(nonGzip, os.O_CREATE|os.O_WRONLY, 0o660)
+	require.NoError(t, err)
+
+	for i := 0; i < 999; i++ {
+		f.WriteString("This is a test file\n")
+		ng.WriteString("This is a test file\n")
+	}
+	f.Close()
+	ng.Close()
+
+	err = compressOldFile(fname, gzip.DefaultCompression)
+	require.NoError(t, err)
+
+	_, err = os.Lstat(fname + ".gz")
+	require.NoError(t, err)
+
+	f, err = os.Open(fname + ".gz")
+	require.NoError(t, err)
+	zr, err := gzip.NewReader(f)
+	require.NoError(t, err)
+	data, err := io.ReadAll(zr)
+	require.NoError(t, err)
+	original, err := os.ReadFile(nonGzip)
+	require.NoError(t, err)
+	assert.Equal(t, original, data)
+}
diff --git a/modules/util/sanitize.go b/modules/util/sanitize.go
new file mode 100644
index 0000000..0dd8b34
--- /dev/null
+++ b/modules/util/sanitize.go
@@ -0,0 +1,72 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"bytes"
+	"unicode"
+)
+
+type sanitizedError struct {
+	err error
+}
+
+func (err sanitizedError) Error() string {
+	return SanitizeCredentialURLs(err.err.Error())
+}
+
+func (err sanitizedError) Unwrap() error {
+	return err.err
+}
+
+// SanitizeErrorCredentialURLs wraps the error and make sure the returned error message doesn't contain sensitive credentials in URLs
+func SanitizeErrorCredentialURLs(err error) error {
+	return sanitizedError{err: err}
+}
+
+const userPlaceholder = "sanitized-credential"
+
+var schemeSep = []byte("://")
+
+// SanitizeCredentialURLs remove all credentials in URLs (starting with "scheme://") for the input string: "https://user:pass@domain.com" => "https://sanitized-credential@domain.com"
+func SanitizeCredentialURLs(s string) string {
+	bs := UnsafeStringToBytes(s)
+	schemeSepPos := bytes.Index(bs, schemeSep)
+	if schemeSepPos == -1 || bytes.IndexByte(bs[schemeSepPos:], '@') == -1 {
+		return s // fast return if there is no URL scheme or no userinfo
+	}
+	out := make([]byte, 0, len(bs)+len(userPlaceholder))
+	for schemeSepPos != -1 {
+		schemeSepPos += 3         // skip the "://"
+		sepAtPos := -1            // the possible '@' position: "https://foo@[^here]host"
+		sepEndPos := schemeSepPos // the possible end position: "The https://host[^here] in log for test"
+	sepLoop:
+		for ; sepEndPos < len(bs); sepEndPos++ {
+			c := bs[sepEndPos]
+			if ('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z') || ('0' <= c && c <= '9') {
+				continue
+			}
+			switch c {
+			case '@':
+				sepAtPos = sepEndPos
+			case '-', '.', '_', '~', '!', '$', '&', '\'', '(', ')', '*', '+', ',', ';', '=', ':', '%':
+				continue // due to RFC 3986, userinfo can contain - . _ ~ ! $ & ' ( ) * + , ; = : and any percent-encoded chars
+			default:
+				break sepLoop // if it is an invalid char for URL (eg: space, '/', and others), stop the loop
+			}
+		}
+		// if there is '@', and the string is like "s://u@h", then hide the "u" part
+		if sepAtPos != -1 && (schemeSepPos >= 4 && unicode.IsLetter(rune(bs[schemeSepPos-4]))) && sepAtPos-schemeSepPos > 0 && sepEndPos-sepAtPos > 0 {
+			out = append(out, bs[:schemeSepPos]...)
+			out = append(out, userPlaceholder...)
+			out = append(out, bs[sepAtPos:sepEndPos]...)
+		} else {
+			out = append(out, bs[:sepEndPos]...)
+		}
+		bs = bs[sepEndPos:]
+		schemeSepPos = bytes.Index(bs, schemeSep)
+	}
+	out = append(out, bs...)
+	return UnsafeBytesToString(out)
+}
diff --git a/modules/util/sanitize_test.go b/modules/util/sanitize_test.go
new file mode 100644
index 0000000..0bcfd45
--- /dev/null
+++ b/modules/util/sanitize_test.go
@@ -0,0 +1,74 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSanitizeErrorCredentialURLs(t *testing.T) {
+	err := errors.New("error with https://a@b.com")
+	se := SanitizeErrorCredentialURLs(err)
+	assert.Equal(t, "error with https://"+userPlaceholder+"@b.com", se.Error())
+}
+
+func TestSanitizeCredentialURLs(t *testing.T) {
+	cases := []struct {
+		input    string
+		expected string
+	}{
+		{
+			"https://github.com/go-gitea/test_repo.git",
+			"https://github.com/go-gitea/test_repo.git",
+		},
+		{
+			"https://mytoken@github.com/go-gitea/test_repo.git",
+			"https://" + userPlaceholder + "@github.com/go-gitea/test_repo.git",
+		},
+		{
+			"https://user:password@github.com/go-gitea/test_repo.git",
+			"https://" + userPlaceholder + "@github.com/go-gitea/test_repo.git",
+		},
+		{
+			"ftp://x@",
+			"ftp://" + userPlaceholder + "@",
+		},
+		{
+			"ftp://x/@",
+			"ftp://x/@",
+		},
+		{
+			"ftp://u@x/@", // test multiple @ chars
+			"ftp://" + userPlaceholder + "@x/@",
+		},
+		{
+			"😊ftp://u@x😊", // test unicode
+			"😊ftp://" + userPlaceholder + "@x😊",
+		},
+		{
+			"://@",
+			"://@",
+		},
+		{
+			"//u:p@h", // do not process URLs without explicit scheme, they are not treated as "valid" URLs because there is no scheme context in string
+			"//u:p@h",
+		},
+		{
+			"s://u@h", // the minimal pattern to be sanitized
+			"s://" + userPlaceholder + "@h",
+		},
+		{
+			"URLs in log https://u:b@h and https://u:b@h:80/, with https://h.com and u@h.com",
+			"URLs in log https://" + userPlaceholder + "@h and https://" + userPlaceholder + "@h:80/, with https://h.com and u@h.com",
+		},
+	}
+
+	for n, c := range cases {
+		result := SanitizeCredentialURLs(c.input)
+		assert.Equal(t, c.expected, result, "case %d: error should match", n)
+	}
+}
diff --git a/modules/util/sec_to_time.go b/modules/util/sec_to_time.go
new file mode 100644
index 0000000..ad0fb1a
--- /dev/null
+++ b/modules/util/sec_to_time.go
@@ -0,0 +1,81 @@
+// Copyright 2022 Gitea. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"fmt"
+	"strings"
+)
+
+// SecToTime converts an amount of seconds to a human-readable string. E.g.
+// 66s			-> 1 minute 6 seconds
+// 52410s		-> 14 hours 33 minutes
+// 563418		-> 6 days 12 hours
+// 1563418		-> 2 weeks 4 days
+// 3937125s     -> 1 month 2 weeks
+// 45677465s	-> 1 year 6 months
+func SecToTime(durationVal any) string {
+	duration, _ := ToInt64(durationVal)
+
+	formattedTime := ""
+
+	// The following four variables are calculated by taking
+	// into account the previously calculated variables, this avoids
+	// pitfalls when using remainders. As that could lead to incorrect
+	// results when the calculated number equals the quotient number.
+	remainingDays := duration / (60 * 60 * 24)
+	years := remainingDays / 365
+	remainingDays -= years * 365
+	months := remainingDays * 12 / 365
+	remainingDays -= months * 365 / 12
+	weeks := remainingDays / 7
+	remainingDays -= weeks * 7
+	days := remainingDays
+
+	// The following three variables are calculated without depending
+	// on the previous calculated variables.
+	hours := (duration / 3600) % 24
+	minutes := (duration / 60) % 60
+	seconds := duration % 60
+
+	// Extract only the relevant information of the time
+	// If the time is greater than a year, it makes no sense to display seconds.
+	switch {
+	case years > 0:
+		formattedTime = formatTime(years, "year", formattedTime)
+		formattedTime = formatTime(months, "month", formattedTime)
+	case months > 0:
+		formattedTime = formatTime(months, "month", formattedTime)
+		formattedTime = formatTime(weeks, "week", formattedTime)
+	case weeks > 0:
+		formattedTime = formatTime(weeks, "week", formattedTime)
+		formattedTime = formatTime(days, "day", formattedTime)
+	case days > 0:
+		formattedTime = formatTime(days, "day", formattedTime)
+		formattedTime = formatTime(hours, "hour", formattedTime)
+	case hours > 0:
+		formattedTime = formatTime(hours, "hour", formattedTime)
+		formattedTime = formatTime(minutes, "minute", formattedTime)
+	default:
+		formattedTime = formatTime(minutes, "minute", formattedTime)
+		formattedTime = formatTime(seconds, "second", formattedTime)
+	}
+
+	// The formatTime() function always appends a space at the end. This will be trimmed
+	return strings.TrimRight(formattedTime, " ")
+}
+
+// formatTime appends the given value to the existing forammattedTime. E.g:
+// formattedTime = "1 year"
+// input: value = 3, name = "month"
+// output will be "1 year 3 months "
+func formatTime(value int64, name, formattedTime string) string {
+	if value == 1 {
+		formattedTime = fmt.Sprintf("%s1 %s ", formattedTime, name)
+	} else if value > 1 {
+		formattedTime = fmt.Sprintf("%s%d %ss ", formattedTime, value, name)
+	}
+
+	return formattedTime
+}
diff --git a/modules/util/sec_to_time_test.go b/modules/util/sec_to_time_test.go
new file mode 100644
index 0000000..4d1213a
--- /dev/null
+++ b/modules/util/sec_to_time_test.go
@@ -0,0 +1,30 @@
+// Copyright 2022 Gitea. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSecToTime(t *testing.T) {
+	second := int64(1)
+	minute := 60 * second
+	hour := 60 * minute
+	day := 24 * hour
+	year := 365 * day
+
+	assert.Equal(t, "1 minute 6 seconds", SecToTime(minute+6*second))
+	assert.Equal(t, "1 hour", SecToTime(hour))
+	assert.Equal(t, "1 hour", SecToTime(hour+second))
+	assert.Equal(t, "14 hours 33 minutes", SecToTime(14*hour+33*minute+30*second))
+	assert.Equal(t, "6 days 12 hours", SecToTime(6*day+12*hour+30*minute+18*second))
+	assert.Equal(t, "2 weeks 4 days", SecToTime((2*7+4)*day+2*hour+16*minute+58*second))
+	assert.Equal(t, "4 weeks", SecToTime(4*7*day))
+	assert.Equal(t, "4 weeks 1 day", SecToTime((4*7+1)*day))
+	assert.Equal(t, "1 month 2 weeks", SecToTime((6*7+3)*day+13*hour+38*minute+45*second))
+	assert.Equal(t, "11 months", SecToTime(year-25*day))
+	assert.Equal(t, "1 year 5 months", SecToTime(year+163*day+10*hour+11*minute+5*second))
+}
diff --git a/modules/util/shellquote.go b/modules/util/shellquote.go
new file mode 100644
index 0000000..434dc42
--- /dev/null
+++ b/modules/util/shellquote.go
@@ -0,0 +1,101 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import "strings"
+
+// Bash has the definition of a metacharacter:
+// * A character that, when unquoted, separates words.
+//   A metacharacter is one of: " \t\n|&;()<>"
+//
+// The following characters also have addition special meaning when unescaped:
+// * ‘${[*?!"'`\’
+//
+// Double Quotes preserve the literal value of all characters with then quotes
+// excepting: ‘$’, ‘`’, ‘\’, and, when history expansion is enabled, ‘!’.
+// The backslash retains its special meaning only when followed by one of the
+// following characters: ‘$’, ‘`’, ‘"’, ‘\’, or newline.
+// Backslashes preceding characters without a special meaning are left
+// unmodified. A double quote may be quoted within double quotes by preceding
+// it with a backslash. If enabled, history expansion will be performed unless
+// an ‘!’ appearing in double quotes is escaped using a backslash. The
+// backslash preceding the ‘!’ is not removed.
+//
+// -> This means that `!\n` cannot be safely expressed in `"`.
+//
+// Looking at the man page for Dash and ash the situation is similar.
+//
+// Now zsh requires that ‘}’, and ‘]’ are also enclosed in doublequotes or escaped
+//
+// Single quotes escape everything except a ‘'’
+//
+// There's one other gotcha - ‘~’ at the start of a string needs to be expanded
+// because people always expect that - of course if there is a special character before '/'
+// this is not going to work
+
+const (
+	tildePrefix      = '~'
+	needsEscape      = " \t\n|&;()<>${}[]*?!\"'`\\"
+	needsSingleQuote = "!\n"
+)
+
+var (
+	doubleQuoteEscaper   = strings.NewReplacer(`$`, `\$`, "`", "\\`", `"`, `\"`, `\`, `\\`)
+	singleQuoteEscaper   = strings.NewReplacer(`'`, `'\''`)
+	singleQuoteCoalescer = strings.NewReplacer(`''\'`, `\'`, `\'''`, `\'`)
+)
+
+// ShellEscape will escape the provided string.
+// We can't just use go-shellquote here because our preferences for escaping differ from those in that we want:
+//
+// * If the string doesn't require any escaping just leave it as it is.
+// * If the string requires any escaping prefer double quote escaping
+// * If we have ! or newlines then we need to use single quote escaping
+func ShellEscape(toEscape string) string {
+	if len(toEscape) == 0 {
+		return toEscape
+	}
+
+	start := 0
+
+	if toEscape[0] == tildePrefix {
+		// We're in the forcibly non-escaped section...
+		idx := strings.IndexRune(toEscape, '/')
+		if idx < 0 {
+			idx = len(toEscape)
+		} else {
+			idx++
+		}
+		if !strings.ContainsAny(toEscape[:idx], needsEscape) {
+			// We'll assume that they intend ~ expansion to occur
+			start = idx
+		}
+	}
+
+	// Now for simplicity we'll look at the rest of the string
+	if !strings.ContainsAny(toEscape[start:], needsEscape) {
+		return toEscape
+	}
+
+	// OK we have to do some escaping
+	sb := &strings.Builder{}
+	_, _ = sb.WriteString(toEscape[:start])
+
+	// Do we have any characters which absolutely need to be within single quotes - that is simply ! or \n?
+	if strings.ContainsAny(toEscape[start:], needsSingleQuote) {
+		// We need to single quote escape.
+		sb2 := &strings.Builder{}
+		_, _ = sb2.WriteRune('\'')
+		_, _ = singleQuoteEscaper.WriteString(sb2, toEscape[start:])
+		_, _ = sb2.WriteRune('\'')
+		_, _ = singleQuoteCoalescer.WriteString(sb, sb2.String())
+		return sb.String()
+	}
+
+	// OK we can just use " just escape the things that need escaping
+	_, _ = sb.WriteRune('"')
+	_, _ = doubleQuoteEscaper.WriteString(sb, toEscape[start:])
+	_, _ = sb.WriteRune('"')
+	return sb.String()
+}
diff --git a/modules/util/shellquote_test.go b/modules/util/shellquote_test.go
new file mode 100644
index 0000000..969998c
--- /dev/null
+++ b/modules/util/shellquote_test.go
@@ -0,0 +1,91 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import "testing"
+
+func TestShellEscape(t *testing.T) {
+	tests := []struct {
+		name     string
+		toEscape string
+		want     string
+	}{
+		{
+			"Simplest case - nothing to escape",
+			"a/b/c/d",
+			"a/b/c/d",
+		}, {
+			"Prefixed tilde - with normal stuff - should not escape",
+			"~/src/go/gitea/gitea",
+			"~/src/go/gitea/gitea",
+		}, {
+			"Typical windows path with spaces - should get doublequote escaped",
+			`C:\Program Files\Gitea v1.13 - I like lots of spaces\gitea`,
+			`"C:\\Program Files\\Gitea v1.13 - I like lots of spaces\\gitea"`,
+		}, {
+			"Forward-slashed windows path with spaces - should get doublequote escaped",
+			"C:/Program Files/Gitea v1.13 - I like lots of spaces/gitea",
+			`"C:/Program Files/Gitea v1.13 - I like lots of spaces/gitea"`,
+		}, {
+			"Prefixed tilde - but then a space filled path",
+			"~git/Gitea v1.13/gitea",
+			`~git/"Gitea v1.13/gitea"`,
+		}, {
+			"Bangs are unfortunately not predictable so need to be singlequoted",
+			"C:/Program Files/Gitea!/gitea",
+			`'C:/Program Files/Gitea!/gitea'`,
+		}, {
+			"Newlines are just irritating",
+			"/home/git/Gitea\n\nWHY-WOULD-YOU-DO-THIS\n\nGitea/gitea",
+			"'/home/git/Gitea\n\nWHY-WOULD-YOU-DO-THIS\n\nGitea/gitea'",
+		}, {
+			"Similarly we should nicely handle multiple single quotes if we have to single-quote",
+			"'!''!'''!''!'!'",
+			`\''!'\'\''!'\'\'\''!'\'\''!'\''!'\'`,
+		}, {
+			"Double quote < ...",
+			"~/<gitea",
+			"~/\"<gitea\"",
+		}, {
+			"Double quote > ...",
+			"~/gitea>",
+			"~/\"gitea>\"",
+		}, {
+			"Double quote and escape $ ...",
+			"~/$gitea",
+			"~/\"\\$gitea\"",
+		}, {
+			"Double quote {...",
+			"~/{gitea",
+			"~/\"{gitea\"",
+		}, {
+			"Double quote }...",
+			"~/gitea}",
+			"~/\"gitea}\"",
+		}, {
+			"Double quote ()...",
+			"~/(gitea)",
+			"~/\"(gitea)\"",
+		}, {
+			"Double quote and escape `...",
+			"~/gitea`",
+			"~/\"gitea\\`\"",
+		}, {
+			"Double quotes can handle a number of things without having to escape them but not everything ...",
+			"~/<gitea> ${gitea} `gitea` [gitea] (gitea) \"gitea\" \\gitea\\ 'gitea'",
+			"~/\"<gitea> \\${gitea} \\`gitea\\` [gitea] (gitea) \\\"gitea\\\" \\\\gitea\\\\ 'gitea'\"",
+		}, {
+			"Single quotes don't need to escape except for '...",
+			"~/<gitea> ${gitea} `gitea` (gitea) !gitea! \"gitea\" \\gitea\\ 'gitea'",
+			"~/'<gitea> ${gitea} `gitea` (gitea) !gitea! \"gitea\" \\gitea\\ '\\''gitea'\\'",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := ShellEscape(tt.toEscape); got != tt.want {
+				t.Errorf("ShellEscape(%q):\nGot:    %s\nWanted: %s", tt.toEscape, got, tt.want)
+			}
+		})
+	}
+}
diff --git a/modules/util/slice.go b/modules/util/slice.go
new file mode 100644
index 0000000..9c878c2
--- /dev/null
+++ b/modules/util/slice.go
@@ -0,0 +1,73 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"cmp"
+	"slices"
+	"strings"
+)
+
+// SliceContainsString sequential searches if string exists in slice.
+func SliceContainsString(slice []string, target string, insensitive ...bool) bool {
+	if len(insensitive) != 0 && insensitive[0] {
+		target = strings.ToLower(target)
+		return slices.ContainsFunc(slice, func(t string) bool { return strings.ToLower(t) == target })
+	}
+
+	return slices.Contains(slice, target)
+}
+
+// SliceSortedEqual returns true if the two slices will be equal when they get sorted.
+// It doesn't require that the slices have been sorted, and it doesn't sort them either.
+func SliceSortedEqual[T comparable](s1, s2 []T) bool {
+	if len(s1) != len(s2) {
+		return false
+	}
+
+	counts := make(map[T]int, len(s1))
+	for _, v := range s1 {
+		counts[v]++
+	}
+	for _, v := range s2 {
+		counts[v]--
+	}
+
+	for _, v := range counts {
+		if v != 0 {
+			return false
+		}
+	}
+	return true
+}
+
+// SliceRemoveAll removes all the target elements from the slice.
+func SliceRemoveAll[T comparable](slice []T, target T) []T {
+	return slices.DeleteFunc(slice, func(t T) bool { return t == target })
+}
+
+// Sorted returns the sorted slice
+// Note: The parameter is sorted inline.
+func Sorted[S ~[]E, E cmp.Ordered](values S) S {
+	slices.Sort(values)
+	return values
+}
+
+// TODO: Replace with "maps.Values" once available, current it only in golang.org/x/exp/maps but not in standard library
+func ValuesOfMap[K comparable, V any](m map[K]V) []V {
+	values := make([]V, 0, len(m))
+	for _, v := range m {
+		values = append(values, v)
+	}
+	return values
+}
+
+// TODO: Replace with "maps.Keys" once available, current it only in golang.org/x/exp/maps but not in standard library
+func KeysOfMap[K comparable, V any](m map[K]V) []K {
+	keys := make([]K, 0, len(m))
+	for k := range m {
+		keys = append(keys, k)
+	}
+	return keys
+}
diff --git a/modules/util/slice_test.go b/modules/util/slice_test.go
new file mode 100644
index 0000000..a910f5e
--- /dev/null
+++ b/modules/util/slice_test.go
@@ -0,0 +1,55 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSliceContainsString(t *testing.T) {
+	assert.True(t, SliceContainsString([]string{"c", "b", "a", "b"}, "a"))
+	assert.True(t, SliceContainsString([]string{"c", "b", "a", "b"}, "b"))
+	assert.True(t, SliceContainsString([]string{"c", "b", "a", "b"}, "A", true))
+	assert.True(t, SliceContainsString([]string{"C", "B", "A", "B"}, "a", true))
+
+	assert.False(t, SliceContainsString([]string{"c", "b", "a", "b"}, "z"))
+	assert.False(t, SliceContainsString([]string{"c", "b", "a", "b"}, "A"))
+	assert.False(t, SliceContainsString([]string{}, "a"))
+	assert.False(t, SliceContainsString(nil, "a"))
+}
+
+func TestSliceSortedEqual(t *testing.T) {
+	assert.True(t, SliceSortedEqual([]int{2, 0, 2, 3}, []int{2, 0, 2, 3}))
+	assert.True(t, SliceSortedEqual([]int{3, 0, 2, 2}, []int{2, 0, 2, 3}))
+	assert.True(t, SliceSortedEqual([]int{}, []int{}))
+	assert.True(t, SliceSortedEqual([]int(nil), nil))
+	assert.True(t, SliceSortedEqual([]int(nil), []int{}))
+	assert.True(t, SliceSortedEqual([]int{}, []int{}))
+
+	assert.True(t, SliceSortedEqual([]string{"2", "0", "2", "3"}, []string{"2", "0", "2", "3"}))
+	assert.True(t, SliceSortedEqual([]float64{2, 0, 2, 3}, []float64{2, 0, 2, 3}))
+	assert.True(t, SliceSortedEqual([]bool{false, true, false}, []bool{false, true, false}))
+
+	assert.False(t, SliceSortedEqual([]int{2, 0, 2}, []int{2, 0, 2, 3}))
+	assert.False(t, SliceSortedEqual([]int{}, []int{2, 0, 2, 3}))
+	assert.False(t, SliceSortedEqual(nil, []int{2, 0, 2, 3}))
+	assert.False(t, SliceSortedEqual([]int{2, 0, 2, 4}, []int{2, 0, 2, 3}))
+	assert.False(t, SliceSortedEqual([]int{2, 0, 0, 3}, []int{2, 0, 2, 3}))
+}
+
+func TestSliceRemoveAll(t *testing.T) {
+	assert.ElementsMatch(t, []int{2, 2, 3}, SliceRemoveAll([]int{2, 0, 2, 3}, 0))
+	assert.ElementsMatch(t, []int{0, 3}, SliceRemoveAll([]int{2, 0, 2, 3}, 2))
+	assert.Empty(t, SliceRemoveAll([]int{0, 0, 0, 0}, 0))
+	assert.ElementsMatch(t, []int{2, 0, 2, 3}, SliceRemoveAll([]int{2, 0, 2, 3}, 4))
+	assert.Empty(t, SliceRemoveAll([]int{}, 0))
+	assert.ElementsMatch(t, []int(nil), SliceRemoveAll([]int(nil), 0))
+	assert.Empty(t, SliceRemoveAll([]int{}, 0))
+
+	assert.ElementsMatch(t, []string{"2", "2", "3"}, SliceRemoveAll([]string{"2", "0", "2", "3"}, "0"))
+	assert.ElementsMatch(t, []float64{2, 2, 3}, SliceRemoveAll([]float64{2, 0, 2, 3}, 0))
+	assert.ElementsMatch(t, []bool{false, false}, SliceRemoveAll([]bool{false, true, false}, true))
+}
diff --git a/modules/util/string.go b/modules/util/string.go
new file mode 100644
index 0000000..cf50f59
--- /dev/null
+++ b/modules/util/string.go
@@ -0,0 +1,97 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import "unsafe"
+
+func isSnakeCaseUpper(c byte) bool {
+	return 'A' <= c && c <= 'Z'
+}
+
+func isSnakeCaseLowerOrNumber(c byte) bool {
+	return 'a' <= c && c <= 'z' || '0' <= c && c <= '9'
+}
+
+// ToSnakeCase convert the input string to snake_case format.
+//
+// Some samples.
+//
+//	"FirstName"  => "first_name"
+//	"HTTPServer" => "http_server"
+//	"NoHTTPS"    => "no_https"
+//	"GO_PATH"    => "go_path"
+//	"GO PATH"    => "go_path"      // space is converted to underscore.
+//	"GO-PATH"    => "go_path"      // hyphen is converted to underscore.
+func ToSnakeCase(input string) string {
+	if len(input) == 0 {
+		return ""
+	}
+
+	var res []byte
+	if len(input) == 1 {
+		c := input[0]
+		if isSnakeCaseUpper(c) {
+			res = []byte{c + 'a' - 'A'}
+		} else if isSnakeCaseLowerOrNumber(c) {
+			res = []byte{c}
+		} else {
+			res = []byte{'_'}
+		}
+	} else {
+		res = make([]byte, 0, len(input)*4/3)
+		pos := 0
+		needSep := false
+		for pos < len(input) {
+			c := input[pos]
+			if c >= 0x80 {
+				res = append(res, c)
+				pos++
+				continue
+			}
+			isUpper := isSnakeCaseUpper(c)
+			if isUpper || isSnakeCaseLowerOrNumber(c) {
+				end := pos + 1
+				if isUpper {
+					// skip the following upper letters
+					for end < len(input) && isSnakeCaseUpper(input[end]) {
+						end++
+					}
+					if end-pos > 1 && end < len(input) && isSnakeCaseLowerOrNumber(input[end]) {
+						end--
+					}
+				}
+				// skip the following lower or number letters
+				for end < len(input) && (isSnakeCaseLowerOrNumber(input[end]) || input[end] >= 0x80) {
+					end++
+				}
+				if needSep {
+					res = append(res, '_')
+				}
+				res = append(res, input[pos:end]...)
+				pos = end
+				needSep = true
+			} else {
+				res = append(res, '_')
+				pos++
+				needSep = false
+			}
+		}
+		for i := 0; i < len(res); i++ {
+			if isSnakeCaseUpper(res[i]) {
+				res[i] += 'a' - 'A'
+			}
+		}
+	}
+	return UnsafeBytesToString(res)
+}
+
+// UnsafeBytesToString uses Go's unsafe package to convert a byte slice to a string.
+func UnsafeBytesToString(b []byte) string {
+	return unsafe.String(unsafe.SliceData(b), len(b))
+}
+
+// UnsafeStringToBytes uses Go's unsafe package to convert a string to a byte slice.
+func UnsafeStringToBytes(s string) []byte {
+	return unsafe.Slice(unsafe.StringData(s), len(s))
+}
diff --git a/modules/util/string_test.go b/modules/util/string_test.go
new file mode 100644
index 0000000..0a4a8bb
--- /dev/null
+++ b/modules/util/string_test.go
@@ -0,0 +1,47 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestToSnakeCase(t *testing.T) {
+	cases := map[string]string{
+		// all old cases from the legacy package
+		"HTTPServer":         "http_server",
+		"_camelCase":         "_camel_case",
+		"NoHTTPS":            "no_https",
+		"Wi_thF":             "wi_th_f",
+		"_AnotherTES_TCaseP": "_another_tes_t_case_p",
+		"ALL":                "all",
+		"_HELLO_WORLD_":      "_hello_world_",
+		"HELLO_WORLD":        "hello_world",
+		"HELLO____WORLD":     "hello____world",
+		"TW":                 "tw",
+		"_C":                 "_c",
+
+		"  sentence case  ": "__sentence_case__",
+		" Mixed-hyphen case _and SENTENCE_case and UPPER-case": "_mixed_hyphen_case__and_sentence_case_and_upper_case",
+
+		// new cases
+		" ":        "_",
+		"A":        "a",
+		"A0":       "a0",
+		"a0":       "a0",
+		"Aa0":      "aa0",
+		"啊":        "啊",
+		"A啊":       "a啊",
+		"Aa啊b":     "aa啊b",
+		"A啊B":      "a啊_b",
+		"Aa啊B":     "aa啊_b",
+		"TheCase2": "the_case2",
+		"ObjIDs":   "obj_i_ds", // the strange database column name which already exists
+	}
+	for input, expected := range cases {
+		assert.Equal(t, expected, ToSnakeCase(input))
+	}
+}
diff --git a/modules/util/timer.go b/modules/util/timer.go
new file mode 100644
index 0000000..f9a7950
--- /dev/null
+++ b/modules/util/timer.go
@@ -0,0 +1,36 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"sync"
+	"time"
+)
+
+func Debounce(d time.Duration) func(f func()) {
+	type debouncer struct {
+		mu sync.Mutex
+		t  *time.Timer
+	}
+	db := &debouncer{}
+
+	return func(f func()) {
+		db.mu.Lock()
+		defer db.mu.Unlock()
+
+		if db.t != nil {
+			db.t.Stop()
+		}
+		var trigger *time.Timer
+		trigger = time.AfterFunc(d, func() {
+			db.mu.Lock()
+			defer db.mu.Unlock()
+			if trigger == db.t {
+				f()
+				db.t = nil
+			}
+		})
+		db.t = trigger
+	}
+}
diff --git a/modules/util/timer_test.go b/modules/util/timer_test.go
new file mode 100644
index 0000000..602800c
--- /dev/null
+++ b/modules/util/timer_test.go
@@ -0,0 +1,30 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDebounce(t *testing.T) {
+	var c int64
+	d := Debounce(50 * time.Millisecond)
+	d(func() { atomic.AddInt64(&c, 1) })
+	assert.EqualValues(t, 0, atomic.LoadInt64(&c))
+	d(func() { atomic.AddInt64(&c, 1) })
+	d(func() { atomic.AddInt64(&c, 1) })
+	time.Sleep(100 * time.Millisecond)
+	assert.EqualValues(t, 1, atomic.LoadInt64(&c))
+	d(func() { atomic.AddInt64(&c, 1) })
+	assert.EqualValues(t, 1, atomic.LoadInt64(&c))
+	d(func() { atomic.AddInt64(&c, 1) })
+	d(func() { atomic.AddInt64(&c, 1) })
+	d(func() { atomic.AddInt64(&c, 1) })
+	time.Sleep(100 * time.Millisecond)
+	assert.EqualValues(t, 2, atomic.LoadInt64(&c))
+}
diff --git a/modules/util/truncate.go b/modules/util/truncate.go
new file mode 100644
index 0000000..77b116e
--- /dev/null
+++ b/modules/util/truncate.go
@@ -0,0 +1,54 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"strings"
+	"unicode/utf8"
+)
+
+// in UTF8 "…" is 3 bytes so doesn't really gain us anything...
+const (
+	utf8Ellipsis  = "…"
+	asciiEllipsis = "..."
+)
+
+// SplitStringAtByteN splits a string at byte n accounting for rune boundaries. (Combining characters are not accounted for.)
+func SplitStringAtByteN(input string, n int) (left, right string) {
+	if len(input) <= n {
+		return input, ""
+	}
+
+	if !utf8.ValidString(input) {
+		if n-3 < 0 {
+			return input, ""
+		}
+		return input[:n-3] + asciiEllipsis, asciiEllipsis + input[n-3:]
+	}
+
+	end := 0
+	for end <= n-3 {
+		_, size := utf8.DecodeRuneInString(input[end:])
+		if end+size > n-3 {
+			break
+		}
+		end += size
+	}
+
+	return input[:end] + utf8Ellipsis, utf8Ellipsis + input[end:]
+}
+
+// SplitTrimSpace splits the string at given separator and trims leading and trailing space
+func SplitTrimSpace(input, sep string) []string {
+	// replace CRLF with LF
+	input = strings.ReplaceAll(input, "\r\n", "\n")
+
+	var stringList []string
+	for _, s := range strings.Split(input, sep) {
+		// trim leading and trailing space
+		stringList = append(stringList, strings.TrimSpace(s))
+	}
+
+	return stringList
+}
diff --git a/modules/util/truncate_test.go b/modules/util/truncate_test.go
new file mode 100644
index 0000000..dfe1230
--- /dev/null
+++ b/modules/util/truncate_test.go
@@ -0,0 +1,46 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSplitString(t *testing.T) {
+	type testCase struct {
+		input    string
+		n        int
+		leftSub  string
+		ellipsis string
+	}
+
+	test := func(tc []*testCase, f func(input string, n int) (left, right string)) {
+		for _, c := range tc {
+			l, r := f(c.input, c.n)
+			if c.ellipsis != "" {
+				assert.Equal(t, c.leftSub+c.ellipsis, l, "test split %q at %d, expected leftSub: %q", c.input, c.n, c.leftSub)
+				assert.Equal(t, c.ellipsis+c.input[len(c.leftSub):], r, "test split %s at %d, expected rightSub: %q", c.input, c.n, c.input[len(c.leftSub):])
+			} else {
+				assert.Equal(t, c.leftSub, l, "test split %q at %d, expected leftSub: %q", c.input, c.n, c.leftSub)
+				assert.Empty(t, r, "test split %q at %d, expected rightSub: %q", c.input, c.n, "")
+			}
+		}
+	}
+
+	tc := []*testCase{
+		{"abc123xyz", 0, "", utf8Ellipsis},
+		{"abc123xyz", 1, "", utf8Ellipsis},
+		{"abc123xyz", 4, "a", utf8Ellipsis},
+		{"啊bc123xyz", 4, "", utf8Ellipsis},
+		{"啊bc123xyz", 6, "啊", utf8Ellipsis},
+		{"啊bc", 5, "啊bc", ""},
+		{"啊bc", 6, "啊bc", ""},
+		{"abc\xef\x03\xfe", 3, "", asciiEllipsis},
+		{"abc\xef\x03\xfe", 4, "a", asciiEllipsis},
+		{"\xef\x03", 1, "\xef\x03", ""},
+	}
+	test(tc, SplitStringAtByteN)
+}
diff --git a/modules/util/url.go b/modules/util/url.go
new file mode 100644
index 0000000..6237033
--- /dev/null
+++ b/modules/util/url.go
@@ -0,0 +1,50 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"net/url"
+	"path"
+	"strings"
+)
+
+// PathEscapeSegments escapes segments of a path while not escaping forward slash
+func PathEscapeSegments(path string) string {
+	slice := strings.Split(path, "/")
+	for index := range slice {
+		slice[index] = url.PathEscape(slice[index])
+	}
+	escapedPath := strings.Join(slice, "/")
+	return escapedPath
+}
+
+// URLJoin joins url components, like path.Join, but preserving contents
+func URLJoin(base string, elems ...string) string {
+	if !strings.HasSuffix(base, "/") {
+		base += "/"
+	}
+	baseURL, err := url.Parse(base)
+	if err != nil {
+		return ""
+	}
+	joinedPath := path.Join(elems...)
+	argURL, err := url.Parse(joinedPath)
+	if err != nil {
+		return ""
+	}
+	joinedURL := baseURL.ResolveReference(argURL).String()
+	if !baseURL.IsAbs() && !strings.HasPrefix(base, "/") {
+		return joinedURL[1:] // Removing leading '/' if needed
+	}
+	return joinedURL
+}
+
+func SanitizeURL(s string) (string, error) {
+	u, err := url.Parse(s)
+	if err != nil {
+		return "", err
+	}
+	u.User = nil
+	return u.String(), nil
+}
diff --git a/modules/util/util.go b/modules/util/util.go
new file mode 100644
index 0000000..dcd7cf4
--- /dev/null
+++ b/modules/util/util.go
@@ -0,0 +1,264 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"bytes"
+	"crypto/ed25519"
+	"crypto/rand"
+	"encoding/pem"
+	"fmt"
+	"math/big"
+	"strconv"
+	"strings"
+
+	"code.gitea.io/gitea/modules/optional"
+
+	"golang.org/x/crypto/ssh"
+	"golang.org/x/text/cases"
+	"golang.org/x/text/language"
+)
+
+// OptionalBoolParse get the corresponding optional.Option[bool] of a string using strconv.ParseBool
+func OptionalBoolParse(s string) optional.Option[bool] {
+	v, e := strconv.ParseBool(s)
+	if e != nil {
+		return optional.None[bool]()
+	}
+	return optional.Some(v)
+}
+
+// IsEmptyString checks if the provided string is empty
+func IsEmptyString(s string) bool {
+	return len(strings.TrimSpace(s)) == 0
+}
+
+// NormalizeEOL will convert Windows (CRLF) and Mac (CR) EOLs to UNIX (LF)
+func NormalizeEOL(input []byte) []byte {
+	var right, left, pos int
+	if right = bytes.IndexByte(input, '\r'); right == -1 {
+		return input
+	}
+	length := len(input)
+	tmp := make([]byte, length)
+
+	// We know that left < length because otherwise right would be -1 from IndexByte.
+	copy(tmp[pos:pos+right], input[left:left+right])
+	pos += right
+	tmp[pos] = '\n'
+	left += right + 1
+	pos++
+
+	for left < length {
+		if input[left] == '\n' {
+			left++
+		}
+
+		right = bytes.IndexByte(input[left:], '\r')
+		if right == -1 {
+			copy(tmp[pos:], input[left:])
+			pos += length - left
+			break
+		}
+		copy(tmp[pos:pos+right], input[left:left+right])
+		pos += right
+		tmp[pos] = '\n'
+		left += right + 1
+		pos++
+	}
+	return tmp[:pos]
+}
+
+// CryptoRandomInt returns a crypto random integer between 0 and limit, inclusive
+func CryptoRandomInt(limit int64) (int64, error) {
+	rInt, err := rand.Int(rand.Reader, big.NewInt(limit))
+	if err != nil {
+		return 0, err
+	}
+	return rInt.Int64(), nil
+}
+
+const alphanumericalChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+
+// CryptoRandomString generates a crypto random alphanumerical string, each byte is generated by [0,61] range
+func CryptoRandomString(length int64) (string, error) {
+	buf := make([]byte, length)
+	limit := int64(len(alphanumericalChars))
+	for i := range buf {
+		num, err := CryptoRandomInt(limit)
+		if err != nil {
+			return "", err
+		}
+		buf[i] = alphanumericalChars[num]
+	}
+	return string(buf), nil
+}
+
+// CryptoRandomBytes generates `length` crypto bytes
+// This differs from CryptoRandomString, as each byte in CryptoRandomString is generated by [0,61] range
+// This function generates totally random bytes, each byte is generated by [0,255] range
+func CryptoRandomBytes(length int64) ([]byte, error) {
+	buf := make([]byte, length)
+	_, err := rand.Read(buf)
+	return buf, err
+}
+
+// ToUpperASCII returns s with all ASCII letters mapped to their upper case.
+func ToUpperASCII(s string) string {
+	b := []byte(s)
+	for i, c := range b {
+		if 'a' <= c && c <= 'z' {
+			b[i] -= 'a' - 'A'
+		}
+	}
+	return string(b)
+}
+
+// ToTitleCase returns s with all english words capitalized
+func ToTitleCase(s string) string {
+	// `cases.Title` is not thread-safe, do not use global shared variable for it
+	return cases.Title(language.English).String(s)
+}
+
+// ToTitleCaseNoLower returns s with all english words capitalized without lower-casing
+func ToTitleCaseNoLower(s string) string {
+	// `cases.Title` is not thread-safe, do not use global shared variable for it
+	return cases.Title(language.English, cases.NoLower).String(s)
+}
+
+// ToInt64 transform a given int into int64.
+func ToInt64(number any) (int64, error) {
+	var value int64
+	switch v := number.(type) {
+	case int:
+		value = int64(v)
+	case int8:
+		value = int64(v)
+	case int16:
+		value = int64(v)
+	case int32:
+		value = int64(v)
+	case int64:
+		value = v
+
+	case uint:
+		value = int64(v)
+	case uint8:
+		value = int64(v)
+	case uint16:
+		value = int64(v)
+	case uint32:
+		value = int64(v)
+	case uint64:
+		value = int64(v)
+
+	case float32:
+		value = int64(v)
+	case float64:
+		value = int64(v)
+
+	case string:
+		var err error
+		if value, err = strconv.ParseInt(v, 10, 64); err != nil {
+			return 0, err
+		}
+	default:
+		return 0, fmt.Errorf("unable to convert %v to int64", number)
+	}
+	return value, nil
+}
+
+// ToFloat64 transform a given int into float64.
+func ToFloat64(number any) (float64, error) {
+	var value float64
+	switch v := number.(type) {
+	case int:
+		value = float64(v)
+	case int8:
+		value = float64(v)
+	case int16:
+		value = float64(v)
+	case int32:
+		value = float64(v)
+	case int64:
+		value = float64(v)
+
+	case uint:
+		value = float64(v)
+	case uint8:
+		value = float64(v)
+	case uint16:
+		value = float64(v)
+	case uint32:
+		value = float64(v)
+	case uint64:
+		value = float64(v)
+
+	case float32:
+		value = float64(v)
+	case float64:
+		value = v
+
+	case string:
+		var err error
+		if value, err = strconv.ParseFloat(v, 64); err != nil {
+			return 0, err
+		}
+	default:
+		return 0, fmt.Errorf("unable to convert %v to float64", number)
+	}
+	return value, nil
+}
+
+// ToPointer returns the pointer of a copy of any given value
+func ToPointer[T any](val T) *T {
+	return &val
+}
+
+// Iif is an "inline-if", it returns "trueVal" if "condition" is true, otherwise "falseVal"
+func Iif[T any](condition bool, trueVal, falseVal T) T {
+	if condition {
+		return trueVal
+	}
+	return falseVal
+}
+
+// IfZero returns "def" if "v" is a zero value, otherwise "v"
+func IfZero[T comparable](v, def T) T {
+	var zero T
+	if v == zero {
+		return def
+	}
+	return v
+}
+
+func ReserveLineBreakForTextarea(input string) string {
+	// Since the content is from a form which is a textarea, the line endings are \r\n.
+	// It's a standard behavior of HTML.
+	// But we want to store them as \n like what GitHub does.
+	// And users are unlikely to really need to keep the \r.
+	// Other than this, we should respect the original content, even leading or trailing spaces.
+	return strings.ReplaceAll(input, "\r\n", "\n")
+}
+
+// GenerateSSHKeypair generates a ed25519 SSH-compatible keypair.
+func GenerateSSHKeypair() (publicKey, privateKey []byte, err error) {
+	public, private, err := ed25519.GenerateKey(nil)
+	if err != nil {
+		return nil, nil, fmt.Errorf("ed25519.GenerateKey: %w", err)
+	}
+
+	privPEM, err := ssh.MarshalPrivateKey(private, "")
+	if err != nil {
+		return nil, nil, fmt.Errorf("ssh.MarshalPrivateKey: %w", err)
+	}
+
+	sshPublicKey, err := ssh.NewPublicKey(public)
+	if err != nil {
+		return nil, nil, fmt.Errorf("ssh.NewPublicKey: %w", err)
+	}
+
+	return ssh.MarshalAuthorizedKey(sshPublicKey), pem.EncodeToMemory(privPEM), nil
+}
diff --git a/modules/util/util_test.go b/modules/util/util_test.go
new file mode 100644
index 0000000..549b53f
--- /dev/null
+++ b/modules/util/util_test.go
@@ -0,0 +1,277 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util_test
+
+import (
+	"bytes"
+	"crypto/rand"
+	"regexp"
+	"strings"
+	"testing"
+
+	"code.gitea.io/gitea/modules/optional"
+	"code.gitea.io/gitea/modules/test"
+	"code.gitea.io/gitea/modules/util"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestURLJoin(t *testing.T) {
+	type test struct {
+		Expected string
+		Base     string
+		Elements []string
+	}
+	newTest := func(expected, base string, elements ...string) test {
+		return test{Expected: expected, Base: base, Elements: elements}
+	}
+	for _, test := range []test{
+		newTest("https://try.gitea.io/a/b/c",
+			"https://try.gitea.io", "a/b", "c"),
+		newTest("https://try.gitea.io/a/b/c",
+			"https://try.gitea.io/", "/a/b/", "/c/"),
+		newTest("https://try.gitea.io/a/c",
+			"https://try.gitea.io/", "/a/./b/", "../c/"),
+		newTest("a/b/c",
+			"a", "b/c/"),
+		newTest("a/b/d",
+			"a/", "b/c/", "/../d/"),
+		newTest("https://try.gitea.io/a/b/c#d",
+			"https://try.gitea.io", "a/b", "c#d"),
+		newTest("/a/b/d",
+			"/a/", "b/c/", "/../d/"),
+		newTest("/a/b/c",
+			"/a", "b/c/"),
+		newTest("/a/b/c#hash",
+			"/a", "b/c#hash"),
+	} {
+		assert.Equal(t, test.Expected, util.URLJoin(test.Base, test.Elements...))
+	}
+}
+
+func TestIsEmptyString(t *testing.T) {
+	cases := []struct {
+		s        string
+		expected bool
+	}{
+		{"", true},
+		{" ", true},
+		{"   ", true},
+		{"  a", false},
+	}
+
+	for _, v := range cases {
+		assert.Equal(t, v.expected, util.IsEmptyString(v.s))
+	}
+}
+
+func Test_NormalizeEOL(t *testing.T) {
+	data1 := []string{
+		"",
+		"This text starts with empty lines",
+		"another",
+		"",
+		"",
+		"",
+		"Some other empty lines in the middle",
+		"more.",
+		"And more.",
+		"Ends with empty lines too.",
+		"",
+		"",
+		"",
+	}
+
+	data2 := []string{
+		"This text does not start with empty lines",
+		"another",
+		"",
+		"",
+		"",
+		"Some other empty lines in the middle",
+		"more.",
+		"And more.",
+		"Ends without EOLtoo.",
+	}
+
+	buildEOLData := func(data []string, eol string) []byte {
+		return []byte(strings.Join(data, eol))
+	}
+
+	dos := buildEOLData(data1, "\r\n")
+	unix := buildEOLData(data1, "\n")
+	mac := buildEOLData(data1, "\r")
+
+	assert.Equal(t, unix, util.NormalizeEOL(dos))
+	assert.Equal(t, unix, util.NormalizeEOL(mac))
+	assert.Equal(t, unix, util.NormalizeEOL(unix))
+
+	dos = buildEOLData(data2, "\r\n")
+	unix = buildEOLData(data2, "\n")
+	mac = buildEOLData(data2, "\r")
+
+	assert.Equal(t, unix, util.NormalizeEOL(dos))
+	assert.Equal(t, unix, util.NormalizeEOL(mac))
+	assert.Equal(t, unix, util.NormalizeEOL(unix))
+
+	assert.Equal(t, []byte("one liner"), util.NormalizeEOL([]byte("one liner")))
+	assert.Equal(t, []byte("\n"), util.NormalizeEOL([]byte("\n")))
+	assert.Equal(t, []byte("\ntwo liner"), util.NormalizeEOL([]byte("\ntwo liner")))
+	assert.Equal(t, []byte("two liner\n"), util.NormalizeEOL([]byte("two liner\n")))
+	assert.Equal(t, []byte{}, util.NormalizeEOL([]byte{}))
+
+	assert.Equal(t, []byte("mix\nand\nmatch\n."), util.NormalizeEOL([]byte("mix\r\nand\rmatch\n.")))
+}
+
+func Test_RandomInt(t *testing.T) {
+	randInt, err := util.CryptoRandomInt(255)
+	assert.GreaterOrEqual(t, randInt, int64(0))
+	assert.LessOrEqual(t, randInt, int64(255))
+	require.NoError(t, err)
+}
+
+func Test_RandomString(t *testing.T) {
+	str1, err := util.CryptoRandomString(32)
+	require.NoError(t, err)
+	matches, err := regexp.MatchString(`^[a-zA-Z0-9]{32}$`, str1)
+	require.NoError(t, err)
+	assert.True(t, matches)
+
+	str2, err := util.CryptoRandomString(32)
+	require.NoError(t, err)
+	matches, err = regexp.MatchString(`^[a-zA-Z0-9]{32}$`, str1)
+	require.NoError(t, err)
+	assert.True(t, matches)
+
+	assert.NotEqual(t, str1, str2)
+
+	str3, err := util.CryptoRandomString(256)
+	require.NoError(t, err)
+	matches, err = regexp.MatchString(`^[a-zA-Z0-9]{256}$`, str3)
+	require.NoError(t, err)
+	assert.True(t, matches)
+
+	str4, err := util.CryptoRandomString(256)
+	require.NoError(t, err)
+	matches, err = regexp.MatchString(`^[a-zA-Z0-9]{256}$`, str4)
+	require.NoError(t, err)
+	assert.True(t, matches)
+
+	assert.NotEqual(t, str3, str4)
+}
+
+func Test_RandomBytes(t *testing.T) {
+	bytes1, err := util.CryptoRandomBytes(32)
+	require.NoError(t, err)
+
+	bytes2, err := util.CryptoRandomBytes(32)
+	require.NoError(t, err)
+
+	assert.NotEqual(t, bytes1, bytes2)
+
+	bytes3, err := util.CryptoRandomBytes(256)
+	require.NoError(t, err)
+
+	bytes4, err := util.CryptoRandomBytes(256)
+	require.NoError(t, err)
+
+	assert.NotEqual(t, bytes3, bytes4)
+}
+
+func TestOptionalBoolParse(t *testing.T) {
+	assert.Equal(t, optional.None[bool](), util.OptionalBoolParse(""))
+	assert.Equal(t, optional.None[bool](), util.OptionalBoolParse("x"))
+
+	assert.Equal(t, optional.Some(false), util.OptionalBoolParse("0"))
+	assert.Equal(t, optional.Some(false), util.OptionalBoolParse("f"))
+	assert.Equal(t, optional.Some(false), util.OptionalBoolParse("False"))
+
+	assert.Equal(t, optional.Some(true), util.OptionalBoolParse("1"))
+	assert.Equal(t, optional.Some(true), util.OptionalBoolParse("t"))
+	assert.Equal(t, optional.Some(true), util.OptionalBoolParse("True"))
+}
+
+// Test case for any function which accepts and returns a single string.
+type StringTest struct {
+	in, out string
+}
+
+var upperTests = []StringTest{
+	{"", ""},
+	{"ONLYUPPER", "ONLYUPPER"},
+	{"abc", "ABC"},
+	{"AbC123", "ABC123"},
+	{"azAZ09_", "AZAZ09_"},
+	{"longStrinGwitHmixofsmaLLandcAps", "LONGSTRINGWITHMIXOFSMALLANDCAPS"},
+	{"long\u0250string\u0250with\u0250nonascii\u2C6Fchars", "LONG\u0250STRING\u0250WITH\u0250NONASCII\u2C6FCHARS"},
+	{"\u0250\u0250\u0250\u0250\u0250", "\u0250\u0250\u0250\u0250\u0250"},
+	{"a\u0080\U0010FFFF", "A\u0080\U0010FFFF"},
+	{"lél", "LéL"},
+}
+
+func TestToUpperASCII(t *testing.T) {
+	for _, tc := range upperTests {
+		assert.Equal(t, util.ToUpperASCII(tc.in), tc.out)
+	}
+}
+
+func BenchmarkToUpper(b *testing.B) {
+	for _, tc := range upperTests {
+		b.Run(tc.in, func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				util.ToUpperASCII(tc.in)
+			}
+		})
+	}
+}
+
+func TestToTitleCase(t *testing.T) {
+	assert.Equal(t, `Foo Bar Baz`, util.ToTitleCase(`foo bar baz`))
+	assert.Equal(t, `Foo Bar Baz`, util.ToTitleCase(`FOO BAR BAZ`))
+}
+
+func TestToPointer(t *testing.T) {
+	assert.Equal(t, "abc", *util.ToPointer("abc"))
+	assert.Equal(t, 123, *util.ToPointer(123))
+	abc := "abc"
+	assert.NotSame(t, &abc, util.ToPointer(abc))
+	val123 := 123
+	assert.NotSame(t, &val123, util.ToPointer(val123))
+}
+
+func TestReserveLineBreakForTextarea(t *testing.T) {
+	assert.Equal(t, "test\ndata", util.ReserveLineBreakForTextarea("test\r\ndata"))
+	assert.Equal(t, "test\ndata\n", util.ReserveLineBreakForTextarea("test\r\ndata\r\n"))
+}
+
+const (
+	testPublicKey  = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIAOhB7/zzhC+HXDdGOdLwJln5NYwm6UNXx3chmQSVTG4\n"
+	testPrivateKey = `-----BEGIN OPENSSH PRIVATE KEY-----
+b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtz
+c2gtZWQyNTUxOQAAACADoQe/884Qvh1w3RjnS8CZZ+TWMJulDV8d3IZkElUxuAAA
+AIggISIjICEiIwAAAAtzc2gtZWQyNTUxOQAAACADoQe/884Qvh1w3RjnS8CZZ+TW
+MJulDV8d3IZkElUxuAAAAEAAAQIDBAUGBwgJCgsMDQ4PEBESExQVFhcYGRobHB0e
+HwOhB7/zzhC+HXDdGOdLwJln5NYwm6UNXx3chmQSVTG4AAAAAAECAwQF
+-----END OPENSSH PRIVATE KEY-----` + "\n"
+)
+
+func TestGeneratingEd25519Keypair(t *testing.T) {
+	defer test.MockProtect(&rand.Reader)()
+
+	// Only 32 bytes needs to be provided to generate a ed25519 keypair.
+	// And another 32 bytes are required, which is included as random value
+	// in the OpenSSH format.
+	b := make([]byte, 64)
+	for i := 0; i < 64; i++ {
+		b[i] = byte(i)
+	}
+	rand.Reader = bytes.NewReader(b)
+
+	publicKey, privateKey, err := util.GenerateSSHKeypair()
+	require.NoError(t, err)
+	assert.EqualValues(t, testPublicKey, string(publicKey))
+	assert.EqualValues(t, testPrivateKey, string(privateKey))
+}