hugo/helpers/general.go
bep 420c9e4d3d Add writable context to Node
The variable scope in the Go templates makes it hard, if possible at all, to write templates with counter variables or similar state.

This commit fixes that by adding a writable context to Node, backed by a map: Scratch.

This context has three methods, Get, Set and Add. The Add is tailored for counter variables, but can be used for any built-in numeric values or strings.
2015-01-31 22:01:30 +01:00

243 lines
5.9 KiB
Go

// Copyright © 2014 Steve Francia <spf@spf13.com>.
//
// Licensed under the Simple Public License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://opensource.org/licenses/Simple-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package helpers
import (
"bytes"
"crypto/md5"
"encoding/hex"
"errors"
"fmt"
"io"
"net"
"path/filepath"
"reflect"
"strings"
bp "github.com/spf13/hugo/bufferpool"
)
// Filepath separator defined by os.Separator.
const FilePathSeparator = string(filepath.Separator)
func FindAvailablePort() (*net.TCPAddr, error) {
l, err := net.Listen("tcp", ":0")
if err == nil {
defer l.Close()
addr := l.Addr()
if a, ok := addr.(*net.TCPAddr); ok {
return a, nil
}
return nil, fmt.Errorf("Unable to obtain a valid tcp port. %v", addr)
}
return nil, err
}
// InStringArray checks if a string is an element of a slice of strings
// and returns a boolean value.
func InStringArray(arr []string, el string) bool {
for _, v := range arr {
if v == el {
return true
}
}
return false
}
// GuessType attempts to guess the type of file from a given string.
func GuessType(in string) string {
switch strings.ToLower(in) {
case "md", "markdown", "mdown":
return "markdown"
case "rst":
return "rst"
case "html", "htm":
return "html"
}
return "unknown"
}
// ReaderToBytes takes an io.Reader argument, reads from it
// and returns bytes.
func ReaderToBytes(lines io.Reader) []byte {
b := bp.GetBuffer()
defer bp.PutBuffer(b)
b.ReadFrom(lines)
bc := make([]byte, b.Len(), b.Len())
copy(bc, b.Bytes())
return bc
}
// ReaderToString is the same as ReaderToBytes, but returns a string.
func ReaderToString(lines io.Reader) string {
b := bp.GetBuffer()
defer bp.PutBuffer(b)
b.ReadFrom(lines)
return b.String()
}
// StringToReader does the opposite of ReaderToString.
func StringToReader(in string) io.Reader {
return strings.NewReader(in)
}
// BytesToReader does the opposite of ReaderToBytes.
func BytesToReader(in []byte) io.Reader {
return bytes.NewReader(in)
}
// SliceToLower goes through the source slice and lowers all values.
func SliceToLower(s []string) []string {
if s == nil {
return nil
}
l := make([]string, len(s))
for i, v := range s {
l[i] = strings.ToLower(v)
}
return l
}
// Md5String takes a string and returns its MD5 hash.
func Md5String(f string) string {
h := md5.New()
h.Write([]byte(f))
return hex.EncodeToString(h.Sum([]byte{}))
}
// DoArithmetic performs arithmetic operations (+,-,*,/) using reflection to
// determine the type of the two terms.
func DoArithmetic(a, b interface{}, op rune) (interface{}, error) {
av := reflect.ValueOf(a)
bv := reflect.ValueOf(b)
var ai, bi int64
var af, bf float64
var au, bu uint64
switch av.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
ai = av.Int()
switch bv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
bi = bv.Int()
case reflect.Float32, reflect.Float64:
af = float64(ai) // may overflow
ai = 0
bf = bv.Float()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
bu = bv.Uint()
if ai >= 0 {
au = uint64(ai)
ai = 0
} else {
bi = int64(bu) // may overflow
bu = 0
}
default:
return nil, errors.New("Can't apply the operator to the values")
}
case reflect.Float32, reflect.Float64:
af = av.Float()
switch bv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
bf = float64(bv.Int()) // may overflow
case reflect.Float32, reflect.Float64:
bf = bv.Float()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
bf = float64(bv.Uint()) // may overflow
default:
return nil, errors.New("Can't apply the operator to the values")
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
au = av.Uint()
switch bv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
bi = bv.Int()
if bi >= 0 {
bu = uint64(bi)
bi = 0
} else {
ai = int64(au) // may overflow
au = 0
}
case reflect.Float32, reflect.Float64:
af = float64(au) // may overflow
au = 0
bf = bv.Float()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
bu = bv.Uint()
default:
return nil, errors.New("Can't apply the operator to the values")
}
case reflect.String:
as := av.String()
if bv.Kind() == reflect.String && op == '+' {
bs := bv.String()
return as + bs, nil
} else {
return nil, errors.New("Can't apply the operator to the values")
}
default:
return nil, errors.New("Can't apply the operator to the values")
}
switch op {
case '+':
if ai != 0 || bi != 0 {
return ai + bi, nil
} else if af != 0 || bf != 0 {
return af + bf, nil
} else if au != 0 || bu != 0 {
return au + bu, nil
} else {
return 0, nil
}
case '-':
if ai != 0 || bi != 0 {
return ai - bi, nil
} else if af != 0 || bf != 0 {
return af - bf, nil
} else if au != 0 || bu != 0 {
return au - bu, nil
} else {
return 0, nil
}
case '*':
if ai != 0 || bi != 0 {
return ai * bi, nil
} else if af != 0 || bf != 0 {
return af * bf, nil
} else if au != 0 || bu != 0 {
return au * bu, nil
} else {
return 0, nil
}
case '/':
if bi != 0 {
return ai / bi, nil
} else if bf != 0 {
return af / bf, nil
} else if bu != 0 {
return au / bu, nil
} else {
return nil, errors.New("Can't divide the value by 0")
}
default:
return nil, errors.New("There is no such an operation")
}
}