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forgejo/modules/base/tool.go
wxiaoguang 5b89670a31
Use a general Eval function for expressions in templates. (#23927)
One of the proposals in #23328

This PR introduces a simple expression calculator
(templates/eval/eval.go), it can do basic expression calculations.

Many untested template helper functions like `Mul` `Add` can be replaced
by this new approach.

Then these `Add` / `Mul` / `percentage` / `Subtract` / `DiffStatsWidth`
could all use this `Eval`.

And it provides enhancements for Golang templates, and improves
readability.

Some examples:

----

* Before: `{{Add (Mul $glyph.Row 12) 12}}`
* After: `{{Eval $glyph.Row "*" 12 "+" 12}}`

----

* Before: `{{if lt (Add $i 1) (len $.Topics)}}`
* After: `{{if Eval $i "+" 1 "<" (len $.Topics)}}`

## FAQ

### Why not use an existing expression package?

We need a highly customized expression engine:

* do the calculation on the fly, without pre-compiling
* deal with int/int64/float64 types, to make the result could be used in
Golang template.
* make the syntax could be used in the Golang template directly
* do not introduce too much complex or strange syntax, we just need a
simple calculator.
* it needs to strictly follow Golang template's behavior, for example,
Golang template treats all non-zero values as truth, but many 3rd
packages don't do so.

### What's the benefit?

* Developers don't need to add more `Add`/`Mul`/`Sub`-like functions,
they were getting more and more.
Now, only one `Eval` is enough for all cases.
* The new code reads better than old `{{Add (Mul $glyph.Row 12) 12}}`,
the old one isn't familiar to most procedural programming developers
(eg, the Golang expression syntax).
* The `Eval` is fully covered by tests, many old `Add`/`Mul`-like
functions were never tested.

### The performance?

It doesn't use `reflect`, it doesn't need to parse or compile when used
in Golang template, the performance is as fast as native Go template.

### Is it too complex? Could it be unstable?

The expression calculator program is a common homework for computer
science students, and it's widely used as a teaching and practicing
purpose for developers. The algorithm is pretty well-known.

The behavior can be clearly defined, it is stable.
2023-04-07 21:25:49 +08:00

269 lines
6.7 KiB
Go

// Copyright 2014 The Gogs Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package base
import (
"crypto/md5"
"crypto/sha1"
"encoding/base64"
"encoding/hex"
"errors"
"fmt"
"os"
"path/filepath"
"runtime"
"strconv"
"strings"
"time"
"unicode"
"unicode/utf8"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"github.com/dustin/go-humanize"
"github.com/minio/sha256-simd"
)
// EncodeMD5 encodes string to md5 hex value.
func EncodeMD5(str string) string {
m := md5.New()
_, _ = m.Write([]byte(str))
return hex.EncodeToString(m.Sum(nil))
}
// EncodeSha1 string to sha1 hex value.
func EncodeSha1(str string) string {
h := sha1.New()
_, _ = h.Write([]byte(str))
return hex.EncodeToString(h.Sum(nil))
}
// EncodeSha256 string to sha256 hex value.
func EncodeSha256(str string) string {
h := sha256.New()
_, _ = h.Write([]byte(str))
return hex.EncodeToString(h.Sum(nil))
}
// ShortSha is basically just truncating.
// It is DEPRECATED and will be removed in the future.
func ShortSha(sha1 string) string {
return TruncateString(sha1, 10)
}
// BasicAuthDecode decode basic auth string
func BasicAuthDecode(encoded string) (string, string, error) {
s, err := base64.StdEncoding.DecodeString(encoded)
if err != nil {
return "", "", err
}
auth := strings.SplitN(string(s), ":", 2)
if len(auth) != 2 {
return "", "", errors.New("invalid basic authentication")
}
return auth[0], auth[1], nil
}
// BasicAuthEncode encode basic auth string
func BasicAuthEncode(username, password string) string {
return base64.StdEncoding.EncodeToString([]byte(username + ":" + password))
}
// VerifyTimeLimitCode verify time limit code
func VerifyTimeLimitCode(data string, minutes int, code string) bool {
if len(code) <= 18 {
return false
}
// split code
start := code[:12]
lives := code[12:18]
if d, err := strconv.ParseInt(lives, 10, 0); err == nil {
minutes = int(d)
}
// right active code
retCode := CreateTimeLimitCode(data, minutes, start)
if retCode == code && minutes > 0 {
// check time is expired or not
before, _ := time.ParseInLocation("200601021504", start, time.Local)
now := time.Now()
if before.Add(time.Minute*time.Duration(minutes)).Unix() > now.Unix() {
return true
}
}
return false
}
// TimeLimitCodeLength default value for time limit code
const TimeLimitCodeLength = 12 + 6 + 40
// CreateTimeLimitCode create a time limit code
// code format: 12 length date time string + 6 minutes string + 40 sha1 encoded string
func CreateTimeLimitCode(data string, minutes int, startInf interface{}) string {
format := "200601021504"
var start, end time.Time
var startStr, endStr string
if startInf == nil {
// Use now time create code
start = time.Now()
startStr = start.Format(format)
} else {
// use start string create code
startStr = startInf.(string)
start, _ = time.ParseInLocation(format, startStr, time.Local)
startStr = start.Format(format)
}
end = start.Add(time.Minute * time.Duration(minutes))
endStr = end.Format(format)
// create sha1 encode string
sh := sha1.New()
_, _ = sh.Write([]byte(fmt.Sprintf("%s%s%s%s%d", data, setting.SecretKey, startStr, endStr, minutes)))
encoded := hex.EncodeToString(sh.Sum(nil))
code := fmt.Sprintf("%s%06d%s", startStr, minutes, encoded)
return code
}
// FileSize calculates the file size and generate user-friendly string.
func FileSize(s int64) string {
return humanize.IBytes(uint64(s))
}
// EllipsisString returns a truncated short string,
// it appends '...' in the end of the length of string is too large.
func EllipsisString(str string, length int) string {
if length <= 3 {
return "..."
}
if utf8.RuneCountInString(str) <= length {
return str
}
return string([]rune(str)[:length-3]) + "..."
}
// TruncateString returns a truncated string with given limit,
// it returns input string if length is not reached limit.
func TruncateString(str string, limit int) string {
if utf8.RuneCountInString(str) < limit {
return str
}
return string([]rune(str)[:limit])
}
// StringsToInt64s converts a slice of string to a slice of int64.
func StringsToInt64s(strs []string) ([]int64, error) {
ints := make([]int64, len(strs))
for i := range strs {
n, err := strconv.ParseInt(strs[i], 10, 64)
if err != nil {
return ints, err
}
ints[i] = n
}
return ints, nil
}
// Int64sToStrings converts a slice of int64 to a slice of string.
func Int64sToStrings(ints []int64) []string {
strs := make([]string, len(ints))
for i := range ints {
strs[i] = strconv.FormatInt(ints[i], 10)
}
return strs
}
// Int64sContains returns if a int64 in a slice of int64
func Int64sContains(intsSlice []int64, a int64) bool {
for _, c := range intsSlice {
if c == a {
return true
}
}
return false
}
// IsLetter reports whether the rune is a letter (category L).
// https://github.com/golang/go/blob/c3b4918/src/go/scanner/scanner.go#L342
func IsLetter(ch rune) bool {
return 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z' || ch == '_' || ch >= 0x80 && unicode.IsLetter(ch)
}
// EntryIcon returns the octicon class for displaying files/directories
func EntryIcon(entry *git.TreeEntry) string {
switch {
case entry.IsLink():
te, err := entry.FollowLink()
if err != nil {
log.Debug(err.Error())
return "file-symlink-file"
}
if te.IsDir() {
return "file-submodule"
}
return "file-symlink-file"
case entry.IsDir():
return "file-directory-fill"
case entry.IsSubModule():
return "file-submodule"
}
return "file"
}
// SetupGiteaRoot Sets GITEA_ROOT if it is not already set and returns the value
func SetupGiteaRoot() string {
giteaRoot := os.Getenv("GITEA_ROOT")
if giteaRoot == "" {
_, filename, _, _ := runtime.Caller(0)
giteaRoot = strings.TrimSuffix(filename, "modules/base/tool.go")
wd, err := os.Getwd()
if err != nil {
rel, err := filepath.Rel(giteaRoot, wd)
if err != nil && strings.HasPrefix(filepath.ToSlash(rel), "../") {
giteaRoot = wd
}
}
if _, err := os.Stat(filepath.Join(giteaRoot, "gitea")); os.IsNotExist(err) {
giteaRoot = ""
} else if err := os.Setenv("GITEA_ROOT", giteaRoot); err != nil {
giteaRoot = ""
}
}
return giteaRoot
}
// FormatNumberSI format a number
func FormatNumberSI(data interface{}) string {
var num int64
if num1, ok := data.(int64); ok {
num = num1
} else if num1, ok := data.(int); ok {
num = int64(num1)
} else {
return ""
}
if num < 1000 {
return fmt.Sprintf("%d", num)
} else if num < 1000000 {
num2 := float32(num) / float32(1000.0)
return fmt.Sprintf("%.1fk", num2)
} else if num < 1000000000 {
num2 := float32(num) / float32(1000000.0)
return fmt.Sprintf("%.1fM", num2)
}
num2 := float32(num) / float32(1000000000.0)
return fmt.Sprintf("%.1fG", num2)
}