drone-yaml/yaml/pretty/writer.go

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// Copyright the Drone Authors.
//
// 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.
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package pretty
import (
"bytes"
"fmt"
"sort"
"strconv"
"github.com/drone/drone-yaml/yaml"
)
// TODO rename WriteTag to WriteKey
// TODO rename WriteTagValue to WriteKeyValue
// ESCAPING:
//
// The string starts with a special character:
// One of !#%@&*`?|>{[ or -.
// The string starts or ends with whitespace characters.
// The string contains : or # character sequences.
// The string ends with a colon.
// The value looks like a number or boolean (123, 1.23, true, false, null) but should be a string.
// Implement state pooling. See:
// https://golang.org/src/fmt/print.go#L131
type writer interface {
// Indent appends padding to the buffer.
Indent()
// IndentIncrease inreases indentation.
IndentIncrease()
// IndentDecrese decreases indentation.
IndentDecrease()
// Write appends the contents of p to the buffer.
Write(p []byte) (n int, err error)
// WriteByte appends the contents of b to the buffer.
WriteByte(b byte) error
// WriteString appends the contents of s to the buffer.
WriteString(s string) (n int, err error)
// WriteTag appends the key to the buffer.
WriteTag(v interface{})
// WriteTag appends the keypair to the buffer.
WriteTagValue(k, v interface{})
}
//
// node writer
//
type baseWriter struct {
bytes.Buffer
depth int
}
func (w *baseWriter) Indent() {
for i := 0; i < w.depth; i++ {
w.WriteString(" ")
}
}
func (w *baseWriter) IndentIncrease() {
w.depth++
}
func (w *baseWriter) IndentDecrease() {
w.depth--
}
func (w *baseWriter) WriteTag(v interface{}) {
w.WriteByte('\n')
w.Indent()
writeValue(w, v)
w.WriteByte(':')
}
func (w *baseWriter) WriteTagValue(k, v interface{}) {
if isZero(v) {
return
}
w.WriteTag(k)
if isPrimative(v) {
w.WriteByte(' ')
writeValue(w, v)
} else if isSlice(v) {
w.WriteByte('\n')
w.Indent()
writeValue(w, v)
} else {
w.depth++
w.WriteByte('\n')
w.Indent()
writeValue(w, v)
w.depth--
}
}
//
// sequence writer
//
type indexWriter struct {
writer
index int
}
func (w *indexWriter) WriteTag(v interface{}) {
w.WriteByte('\n')
if w.index == 0 {
w.IndentDecrease()
w.Indent()
w.IndentIncrease()
w.WriteByte('-')
w.WriteByte(' ')
} else {
w.Indent()
}
writeValue(w, v)
w.WriteByte(':')
w.index++
}
func (w *indexWriter) WriteTagValue(k, v interface{}) {
if isZero(v) {
return
}
w.WriteTag(k)
if isPrimative(v) {
w.WriteByte(' ')
writeValue(w, v)
} else if isSlice(v) {
w.WriteByte('\n')
w.Indent()
writeValue(w, v)
} else {
w.IndentIncrease()
w.WriteByte('\n')
w.Indent()
writeValue(w, v)
w.IndentDecrease()
}
}
//
// helper functions
//
func writeBool(w writer, v bool) {
w.WriteString(
strconv.FormatBool(v),
)
}
func writeFloat(w writer, v float64) {
w.WriteString(
strconv.FormatFloat(v, 'g', -1, 64),
)
}
func writeInt(w writer, v int) {
w.WriteString(
strconv.Itoa(v),
)
}
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func writeInt64(w writer, v int64) {
w.WriteString(
strconv.FormatInt(v, 10),
)
}
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func writeEncode(w writer, v string) {
if len(v) == 0 {
w.WriteByte('"')
w.WriteByte('"')
return
}
for _, b := range v {
if isQuoted(b) {
fmt.Fprintf(w, "%q", v)
return
}
}
w.WriteString(v)
}
func writeValue(w writer, v interface{}) {
if v == nil {
w.WriteByte('~')
return
}
switch v := v.(type) {
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case bool, int, int64, float64, string:
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writeScalar(w, v)
case []interface{}:
writeSequence(w, v)
case []string:
writeSequenceStr(w, v)
case map[interface{}]interface{}:
writeMapping(w, v)
case map[string]string:
writeMappingStr(w, v)
case yaml.BytesSize:
writeValue(w, v.String())
}
}
func writeScalar(w writer, v interface{}) {
switch v := v.(type) {
case bool:
writeBool(w, v)
case int:
writeInt(w, v)
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case int64:
writeInt64(w, v)
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case float64:
writeFloat(w, v)
case string:
writeEncode(w, v)
}
}
func writeSequence(w writer, v []interface{}) {
if len(v) == 0 {
w.WriteByte('[')
w.WriteByte(']')
return
}
for i, v := range v {
if i != 0 {
w.WriteByte('\n')
w.Indent()
}
w.WriteByte('-')
w.WriteByte(' ')
w.IndentIncrease()
writeValue(w, v)
w.IndentDecrease()
}
}
func writeSequenceStr(w writer, v []string) {
if len(v) == 0 {
w.WriteByte('[')
w.WriteByte(']')
return
}
for i, v := range v {
if i != 0 {
w.WriteByte('\n')
w.Indent()
}
w.WriteByte('-')
w.WriteByte(' ')
writeEncode(w, v)
}
}
func writeMapping(w writer, v map[interface{}]interface{}) {
if len(v) == 0 {
w.WriteByte('{')
w.WriteByte('}')
return
}
var keys []string
for k := range v {
s := fmt.Sprint(k)
keys = append(keys, s)
}
sort.Strings(keys)
for i, k := range keys {
v := v[k]
if i != 0 {
w.WriteByte('\n')
w.Indent()
}
writeEncode(w, k)
w.WriteByte(':')
if v == nil || isPrimative(v) || isZero(v) {
w.WriteByte(' ')
writeValue(w, v)
} else {
slice := isSlice(v)
if !slice {
w.IndentIncrease()
}
w.WriteByte('\n')
w.Indent()
writeValue(w, v)
if !slice {
w.IndentDecrease()
}
}
}
}
func writeMappingStr(w writer, v map[string]string) {
if len(v) == 0 {
w.WriteByte('{')
w.WriteByte('}')
return
}
var keys []string
for k := range v {
keys = append(keys, k)
}
sort.Strings(keys)
for i, k := range keys {
v := v[k]
if i != 0 {
w.WriteByte('\n')
w.Indent()
}
writeEncode(w, k)
w.WriteByte(':')
w.WriteByte(' ')
writeEncode(w, v)
}
}