/
json_encode.go
358 lines (293 loc) · 7.33 KB
/
json_encode.go
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package types
import (
"encoding/json"
"fmt"
"io"
"reflect"
"sort"
"strconv"
"time"
"github.com/shopspring/decimal"
)
var isEscaped = [256]bool{}
var escapeSeq = [256][]byte{}
func init() {
isEscaped[uint8('\b')] = true
isEscaped[uint8('\f')] = true
isEscaped[uint8('\n')] = true
isEscaped[uint8('\r')] = true
isEscaped[uint8('\t')] = true
isEscaped[uint8('"')] = true
isEscaped[uint8('\\')] = true
escapeSeq[uint8('\b')] = []byte("\\b")
escapeSeq[uint8('\f')] = []byte("\\f")
escapeSeq[uint8('\n')] = []byte("\\n")
escapeSeq[uint8('\r')] = []byte("\\r")
escapeSeq[uint8('\t')] = []byte("\\t")
escapeSeq[uint8('"')] = []byte("\\\"")
escapeSeq[uint8('\\')] = []byte("\\\\")
decimal.MarshalJSONWithoutQuotes = true
}
type NoCopyBuilder struct {
buffers [][]byte
curr int
lastAlloc int64
totalSize int64
}
func NewNoCopyBuilder(initialAlloc int64) *NoCopyBuilder {
return &NoCopyBuilder{
buffers: [][]byte{make([]byte, 0, initialAlloc)},
lastAlloc: initialAlloc,
}
}
func (b *NoCopyBuilder) Write(p []byte) (int, error) {
currBuff := b.buffers[b.curr]
toWrite := len(p)
sourcePos := 0
destPos := len(currBuff)
space := cap(currBuff) - destPos
if space > 0 {
firstWrite := toWrite
if firstWrite > space {
firstWrite = space
}
currBuff = currBuff[:destPos+firstWrite]
n := copy(currBuff[destPos:], p[sourcePos:firstWrite])
b.buffers[b.curr] = currBuff
if n != firstWrite {
return -1, fmt.Errorf("failed to copy %d bytes to buffer", firstWrite)
}
toWrite -= firstWrite
sourcePos += firstWrite
}
if toWrite > 0 {
toAlloc := b.lastAlloc * 2
if toAlloc < int64(toWrite) {
toAlloc = int64(toWrite * 2)
}
newBuff := make([]byte, toWrite, toAlloc)
b.buffers = append(b.buffers, newBuff)
b.curr++
b.lastAlloc = toAlloc
n := copy(newBuff, p[sourcePos:])
if n != toWrite {
return -1, fmt.Errorf("failed to copy %d bytes to buffer", toWrite)
}
}
b.totalSize += int64(len(p))
return len(p), nil
}
func (b *NoCopyBuilder) Bytes() []byte {
if len(b.buffers) == 1 {
return b.buffers[0]
}
res := make([]byte, b.totalSize)
pos := 0
for _, buff := range b.buffers {
n := copy(res[pos:], buff)
if n != len(buff) {
panic(fmt.Errorf("failed to copy %d bytes to buffer", len(buff)))
}
pos += len(buff)
}
return res
}
func (b *NoCopyBuilder) String() string {
return string(b.Bytes())
}
func WriteStrings(wr io.Writer, strs ...string) (int, error) {
var totalN int
for _, str := range strs {
n, err := wr.Write([]byte(str))
if err != nil {
return totalN, err
}
totalN += n
}
return totalN, nil
}
// marshalToMySqlString is a helper function to marshal a JSONDocument to a string that is
// compatible with MySQL's JSON output, including spaces.
func marshalToMySqlString(val interface{}) (string, error) {
b := NewNoCopyBuilder(1024)
err := writeMarshalledValue(b, val)
if err != nil {
return "", err
}
return b.String(), nil
}
func sortKeys[T any](m map[string]T) []string {
var keys []string
for k := range m {
keys = append(keys, k)
}
sort.Slice(keys, func(i, j int) bool {
if len(keys[i]) != len(keys[j]) {
return len(keys[i]) < len(keys[j])
}
return keys[i] < keys[j]
})
return keys
}
func writeMarshalledValue(writer io.Writer, val interface{}) error {
switch val := val.(type) {
case []interface{}:
writer.Write([]byte{'['})
for i, v := range val {
err := writeMarshalledValue(writer, v)
if err != nil {
return err
}
if i != len(val)-1 {
writer.Write([]byte{',', ' '})
}
}
writer.Write([]byte{']'})
return nil
case map[string]string:
keys := sortKeys(val)
writer.Write([]byte{'{'})
for i, k := range keys {
writer.Write([]byte{'"'})
writer.Write([]byte(k))
writer.Write([]byte(`": "`))
writer.Write([]byte(val[k]))
writer.Write([]byte{'"'})
if i != len(keys)-1 {
writer.Write([]byte{',', ' '})
}
}
writer.Write([]byte{'}'})
return nil
case map[string]interface{}:
keys := sortKeys(val)
writer.Write([]byte{'{'})
for i, k := range keys {
writer.Write([]byte{'"'})
writer.Write([]byte(k))
writer.Write([]byte(`": `))
err := writeMarshalledValue(writer, val[k])
if err != nil {
return err
}
if i != len(keys)-1 {
writer.Write([]byte{',', ' '})
}
}
writer.Write([]byte{'}'})
return nil
case string:
writer.Write([]byte{'"'})
// iterate over each rune in the string to escape any special characters
start := 0
for i, r := range val {
if r > '\\' {
continue
}
b := uint8(r)
if isEscaped[b] {
if start != i {
writer.Write([]byte(val[start:i]))
}
writer.Write(escapeSeq[b])
start = i + 1
}
}
if start != len(val) {
writer.Write([]byte(val[start:]))
}
writer.Write([]byte{'"'})
return nil
case float64:
// JSON doesn't distinguish between integers and floats, so we need to check if the float is an integer
if val == float64(int64(val)) {
_, err := writer.Write([]byte(strconv.FormatInt(int64(val), 10)))
return err
}
_, err := writer.Write([]byte(strconv.FormatFloat(val, 'f', -1, 64)))
return err
case float32:
// JSON doesn't distinguish between integers and floats, so we need to check if the float is an integer
if val == float32(int32(val)) {
_, err := writer.Write([]byte(strconv.FormatInt(int64(val), 10)))
return err
}
_, err := writer.Write([]byte(strconv.FormatFloat(float64(val), 'f', -1, 32)))
return err
case int64:
_, err := writer.Write([]byte(strconv.FormatInt(val, 10)))
return err
case int32:
_, err := writer.Write([]byte(strconv.FormatInt(int64(val), 10)))
return err
case int16:
_, err := writer.Write([]byte(strconv.FormatInt(int64(val), 10)))
return err
case int8:
_, err := writer.Write([]byte(strconv.FormatInt(int64(val), 10)))
return err
case int:
_, err := writer.Write([]byte(strconv.FormatInt(int64(val), 10)))
return err
case uint64:
_, err := writer.Write([]byte(strconv.FormatUint(val, 10)))
return err
case uint32:
_, err := writer.Write([]byte(strconv.FormatUint(uint64(val), 10)))
return err
case uint16:
_, err := writer.Write([]byte(strconv.FormatUint(uint64(val), 10)))
return err
case uint8:
_, err := writer.Write([]byte(strconv.FormatUint(uint64(val), 10)))
return err
case bool:
if val {
writer.Write([]byte("true"))
} else {
writer.Write([]byte("false"))
}
return nil
case nil:
writer.Write([]byte("null"))
return nil
case time.Time:
writer.Write([]byte{'"'})
writer.Write([]byte(val.Format(time.RFC3339)))
writer.Write([]byte{'"'})
return nil
case json.Marshaler:
decimal.MarshalJSONWithoutQuotes = true
bytes, err := val.MarshalJSON()
if err != nil {
return err
}
writer.Write(bytes)
return nil
default:
r := reflect.ValueOf(val)
switch r.Kind() {
case reflect.Slice, reflect.Array:
writer.Write([]byte{'['})
for i := 0; i < r.Len(); i++ {
err := writeMarshalledValue(writer, r.Index(i).Interface())
if err != nil {
return err
}
if i != r.Len()-1 {
writer.Write([]byte{',', ' '})
}
}
writer.Write([]byte{']'})
return nil
case reflect.Map:
interfMap := make(map[string]interface{})
for _, k := range r.MapKeys() {
interfMap[k.String()] = r.MapIndex(k).Interface()
}
return writeMarshalledValue(writer, interfMap)
default:
return fmt.Errorf("unsupported type: %T", val)
}
}
}