status-go/vendor/github.com/russolsen/transit/emitter.go

153 lines
3.4 KiB
Go

// Copyright 2016 Russ Olsen. All Rights Reserved.
//
// This code is a Go port of the Java version created and maintained by Cognitect, therefore:
//
// Copyright 2014 Cognitect. All Rights Reserved.
//
// Licensed under the Apache 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://www.apache.org/licenses/LICENSE-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 transit
import (
"encoding/json"
"fmt"
"io"
"strings"
)
type DataEmitter interface {
Emit(s string) error
EmitString(s string, cacheable bool) error
EmitTag(s string) error
EmitInt(i int64, asKey bool) error
EmitFloat(f float64, asKey bool) error
EmitNil(asKey bool) error
EmitBool(bool, asKey bool) error
EmitStartArray() error
EmitArraySeparator() error
EmitEndArray() error
EmitStartMap() error
EmitMapSeparator() error
EmitKeySeparator() error
EmitEndMap() error
}
type JsonEmitter struct {
writer io.Writer
cache Cache
}
func NewJsonEmitter(w io.Writer, cache Cache) *JsonEmitter {
return &JsonEmitter{writer: w, cache: cache}
}
// Emit the string unaltered and without quotes. This is the lowest level emitter.
func (je JsonEmitter) Emit(s string) error {
_, err := je.writer.Write([]byte(s))
return err
}
// EmitBase emits the basic value supplied, encoding it as JSON.
func (je JsonEmitter) EmitBase(x interface{}) error {
bytes, err := json.Marshal(x)
if err == nil {
_, err = je.writer.Write(bytes)
}
return err
}
// EmitsTag emits a transit #tag. The string supplied should not include the '#'.
func (je JsonEmitter) EmitTag(s string) error {
return je.EmitString("~#"+s, true)
}
func (je JsonEmitter) EmitString(s string, cacheable bool) error {
if je.cache.IsCacheable(s, cacheable) {
s = je.cache.Write(s)
}
return je.EmitBase(s)
}
const MaxJsonInt = 1<<53 - 1
func (je JsonEmitter) EmitInt(i int64, asKey bool) error {
if asKey || (i > MaxJsonInt) {
return je.EmitString(fmt.Sprintf("~i%d", i), asKey)
}
return je.EmitBase(i)
}
func (je JsonEmitter) EmitNil(asKey bool) error {
if asKey {
return je.EmitString("~_", false)
} else {
return je.EmitBase(nil)
}
}
func (je JsonEmitter) EmitFloat(f float64, asKey bool) error {
if asKey {
return je.EmitString(fmt.Sprintf("~d%g", f), asKey)
} else {
s := fmt.Sprintf("%g", f)
if !strings.ContainsAny(s, ".eE") {
s = s + ".0" // Horible hack!
}
return je.Emit(s)
}
}
func (je JsonEmitter) EmitStartArray() error {
return je.Emit("[")
}
func (je JsonEmitter) EmitEndArray() error {
return je.Emit("]")
}
func (je JsonEmitter) EmitArraySeparator() error {
return je.Emit(",")
}
func (je JsonEmitter) EmitStartMap() error {
return je.Emit("{")
}
func (je JsonEmitter) EmitEndMap() error {
return je.Emit("}")
}
func (je JsonEmitter) EmitMapSeparator() error {
return je.Emit(",")
}
func (je JsonEmitter) EmitKeySeparator() error {
return je.Emit(":")
}
func (je JsonEmitter) EmitBool(x bool, asKey bool) error {
if asKey {
if x {
return je.EmitString("~?t", false)
} else {
return je.EmitString("~?f", false)
}
} else {
return je.EmitBase(x)
}
}