Merge pull request #65383 from sigma/pr/update-toml

Godeps/Godeps.json

@@ -2490,8 +2490,8 @@
 		},
 		{
 			"ImportPath": "github.com/pelletier/go-toml",
-			"Comment": "v1.0.1",
-			"Rev": "16398bac157da96aa88f98a2df640c7f32af1da2"
+			"Comment": "v1.2.0",
+			"Rev": "c01d1270ff3e442a8a57cddc1c92dc1138598194"
 		},
 		{
 			"ImportPath": "github.com/peterbourgon/diskv",

vendor/github.com/pelletier/go-toml/.gitignore

 test_program/test_program_bin
+fuzz/

vendor/github.com/pelletier/go-toml/.travis.yml

 sudo: false
 language: go
 go:
-  - 1.7.6
-  - 1.8.3
-  - 1.9
+  - 1.8.x
+  - 1.9.x
+  - 1.10.x
   - tip
 matrix:
   allow_failures:

vendor/github.com/pelletier/go-toml/README.md

@@ -57,9 +57,9 @@ type Config struct {
 }
 
 doc := []byte(`
-[postgres]
-user = "pelletier"
-password = "mypassword"`)
+[Postgres]
+User = "pelletier"
+Password = "mypassword"`)
 
 config := Config{}
 toml.Unmarshal(doc, &config)
@@ -114,6 +114,18 @@ You have to make sure two kind of tests run:
 
 You can run both of them using `./test.sh`.
 
+### Fuzzing
+
+The script `./fuzz.sh` is available to
+run [go-fuzz](https://github.com/dvyukov/go-fuzz) on go-toml.
+
+## Versioning
+
+Go-toml follows [Semantic Versioning](http://semver.org/). The supported version
+of [TOML](https://github.com/toml-lang/toml) is indicated at the beginning of
+this document. The last two major versions of Go are supported
+(see [Go Release Policy](https://golang.org/doc/devel/release.html#policy)).
+
 ## License
 
 The MIT License (MIT). Read [LICENSE](LICENSE).

vendor/github.com/pelletier/go-toml/doc.go

@@ -17,7 +17,7 @@
 // JSONPath-like queries
 //
 // The package github.com/pelletier/go-toml/query implements a system
-// similar to JSONPath to quickly retrive elements of a TOML document using a
+// similar to JSONPath to quickly retrieve elements of a TOML document using a
 // single expression. See the package documentation for more information.
 //
 package toml

vendor/github.com/pelletier/go-toml/fuzz.go

+// +build gofuzz
+
+package toml
+
+func Fuzz(data []byte) int {
+	tree, err := LoadBytes(data)
+	if err != nil {
+		if tree != nil {
+			panic("tree must be nil if there is an error")
+		}
+		return 0
+	}
+
+	str, err := tree.ToTomlString()
+	if err != nil {
+		if str != "" {
+			panic(`str must be "" if there is an error`)
+		}
+		panic(err)
+	}
+
+	tree, err = Load(str)
+	if err != nil {
+		if tree != nil {
+			panic("tree must be nil if there is an error")
+		}
+		return 0
+	}
+
+	return 1
+}

vendor/github.com/pelletier/go-toml/fuzz.sh

+#! /bin/sh
+set -eu
+
+go get github.com/dvyukov/go-fuzz/go-fuzz
+go get github.com/dvyukov/go-fuzz/go-fuzz-build
+
+if [ ! -e toml-fuzz.zip ]; then
+    go-fuzz-build github.com/pelletier/go-toml
+fi
+
+rm -fr fuzz
+mkdir -p fuzz/corpus
+cp *.toml fuzz/corpus
+
+go-fuzz -bin=toml-fuzz.zip -workdir=fuzz

vendor/github.com/pelletier/go-toml/keysparsing.go

@@ -9,12 +9,14 @@ import (
 	"unicode"
 )
 
+// Convert the bare key group string to an array.
+// The input supports double quotation to allow "." inside the key name,
+// but escape sequences are not supported. Lexers must unescape them beforehand.
 func parseKey(key string) ([]string, error) {
 	groups := []string{}
 	var buffer bytes.Buffer
 	inQuotes := false
 	wasInQuotes := false
-	escapeNext := false
 	ignoreSpace := true
 	expectDot := false
 
@@ -25,15 +27,7 @@ func parseKey(key string) ([]string, error) {
 			}
 			ignoreSpace = false
 		}
-		if escapeNext {
-			buffer.WriteRune(char)
-			escapeNext = false
-			continue
-		}
 		switch char {
-		case '\\':
-			escapeNext = true
-			continue
 		case '"':
 			if inQuotes {
 				groups = append(groups, buffer.String())
@@ -77,9 +71,6 @@ func parseKey(key string) ([]string, error) {
 	if inQuotes {
 		return nil, errors.New("mismatched quotes")
 	}
-	if escapeNext {
-		return nil, errors.New("unfinished escape sequence")
-	}
 	if buffer.Len() > 0 {
 		groups = append(groups, buffer.String())
 	}

vendor/github.com/pelletier/go-toml/lexer.go

@@ -204,6 +204,14 @@ func (l *tomlLexer) lexRvalue() tomlLexStateFn {
 			return l.lexFalse
 		}
 
+		if l.follow("inf") {
+			return l.lexInf
+		}
+
+		if l.follow("nan") {
+			return l.lexNan
+		}
+
 		if isSpace(next) {
 			l.skip()
 			continue
@@ -265,6 +273,18 @@ func (l *tomlLexer) lexFalse() tomlLexStateFn {
 	return l.lexRvalue
 }
 
+func (l *tomlLexer) lexInf() tomlLexStateFn {
+	l.fastForward(3)
+	l.emit(tokenInf)
+	return l.lexRvalue
+}
+
+func (l *tomlLexer) lexNan() tomlLexStateFn {
+	l.fastForward(3)
+	l.emit(tokenNan)
+	return l.lexRvalue
+}
+
 func (l *tomlLexer) lexEqual() tomlLexStateFn {
 	l.next()
 	l.emit(tokenEqual)
@@ -277,6 +297,8 @@ func (l *tomlLexer) lexComma() tomlLexStateFn {
 	return l.lexRvalue
 }
 
+// Parse the key and emits its value without escape sequences.
+// bare keys, basic string keys and literal string keys are supported.
 func (l *tomlLexer) lexKey() tomlLexStateFn {
 	growingString := ""
 
@@ -287,7 +309,16 @@ func (l *tomlLexer) lexKey() tomlLexStateFn {
 			if err != nil {
 				return l.errorf(err.Error())
 			}
-			growingString += `"` + str + `"`
+			growingString += str
+			l.next()
+			continue
+		} else if r == '\'' {
+			l.next()
+			str, err := l.lexLiteralStringAsString(`'`, false)
+			if err != nil {
+				return l.errorf(err.Error())
+			}
+			growingString += str
 			l.next()
 			continue
 		} else if r == '\n' {
@@ -527,6 +558,7 @@ func (l *tomlLexer) lexTableKey() tomlLexStateFn {
 	return l.lexInsideTableKey
 }
 
+// Parse the key till "]]", but only bare keys are supported
 func (l *tomlLexer) lexInsideTableArrayKey() tomlLexStateFn {
 	for r := l.peek(); r != eof; r = l.peek() {
 		switch r {
@@ -550,6 +582,7 @@ func (l *tomlLexer) lexInsideTableArrayKey() tomlLexStateFn {
 	return l.errorf("unclosed table array key")
 }
 
+// Parse the key till "]" but only bare keys are supported
 func (l *tomlLexer) lexInsideTableKey() tomlLexStateFn {
 	for r := l.peek(); r != eof; r = l.peek() {
 		switch r {
@@ -575,11 +608,77 @@ func (l *tomlLexer) lexRightBracket() tomlLexStateFn {
 	return l.lexRvalue
 }
 
+type validRuneFn func(r rune) bool
+
+func isValidHexRune(r rune) bool {
+	return r >= 'a' && r <= 'f' ||
+		r >= 'A' && r <= 'F' ||
+		r >= '0' && r <= '9' ||
+		r == '_'
+}
+
+func isValidOctalRune(r rune) bool {
+	return r >= '0' && r <= '7' || r == '_'
+}
+
+func isValidBinaryRune(r rune) bool {
+	return r == '0' || r == '1' || r == '_'
+}
+
 func (l *tomlLexer) lexNumber() tomlLexStateFn {
 	r := l.peek()
+
+	if r == '0' {
+		follow := l.peekString(2)
+		if len(follow) == 2 {
+			var isValidRune validRuneFn
+			switch follow[1] {
+			case 'x':
+				isValidRune = isValidHexRune
+			case 'o':
+				isValidRune = isValidOctalRune
+			case 'b':
+				isValidRune = isValidBinaryRune
+			default:
+				if follow[1] >= 'a' && follow[1] <= 'z' || follow[1] >= 'A' && follow[1] <= 'Z' {
+					return l.errorf("unknown number base: %s. possible options are x (hex) o (octal) b (binary)", string(follow[1]))
+				}
+			}
+
+			if isValidRune != nil {
+				l.next()
+				l.next()
+				digitSeen := false
+				for {
+					next := l.peek()
+					if !isValidRune(next) {
+						break
+					}
+					digitSeen = true
+					l.next()
+				}
+
+				if !digitSeen {
+					return l.errorf("number needs at least one digit")
+				}
+
+				l.emit(tokenInteger)
+
+				return l.lexRvalue
+			}
+		}
+	}
+
 	if r == '+' || r == '-' {
 		l.next()
+		if l.follow("inf") {
+			return l.lexInf
+		}
+		if l.follow("nan") {
+			return l.lexNan
+		}
 	}
+
 	pointSeen := false
 	expSeen := false
 	digitSeen := false

vendor/github.com/pelletier/go-toml/parser.go

@@ -5,6 +5,7 @@ package toml
 import (
 	"errors"
 	"fmt"
+	"math"
 	"reflect"
 	"regexp"
 	"strconv"
@@ -185,10 +186,7 @@ func (p *tomlParser) parseAssign() tomlParserStateFn {
 	}
 
 	// assign value to the found table
-	keyVals, err := parseKey(key.val)
-	if err != nil {
-		p.raiseError(key, "%s", err)
-	}
+	keyVals := []string{key.val}
 	if len(keyVals) != 1 {
 		p.raiseError(key, "Invalid key")
 	}
@@ -205,20 +203,32 @@ func (p *tomlParser) parseAssign() tomlParserStateFn {
 	case *Tree, []*Tree:
 		toInsert = value
 	default:
-		toInsert = &tomlValue{value, key.Position}
+		toInsert = &tomlValue{value: value, position: key.Position}
 	}
 	targetNode.values[keyVal] = toInsert
 	return p.parseStart
 }
 
 var numberUnderscoreInvalidRegexp *regexp.Regexp
+var hexNumberUnderscoreInvalidRegexp *regexp.Regexp
 
-func cleanupNumberToken(value string) (string, error) {
+func numberContainsInvalidUnderscore(value string) error {
 	if numberUnderscoreInvalidRegexp.MatchString(value) {
-		return "", errors.New("invalid use of _ in number")
+		return errors.New("invalid use of _ in number")
+	}
+	return nil
+}
+
+func hexNumberContainsInvalidUnderscore(value string) error {
+	if hexNumberUnderscoreInvalidRegexp.MatchString(value) {
+		return errors.New("invalid use of _ in hex number")
 	}
+	return nil
+}
+
+func cleanupNumberToken(value string) string {
 	cleanedVal := strings.Replace(value, "_", "", -1)
-	return cleanedVal, nil
+	return cleanedVal
 }
 
 func (p *tomlParser) parseRvalue() interface{} {
@@ -234,21 +244,57 @@ func (p *tomlParser) parseRvalue() interface{} {
 		return true
 	case tokenFalse:
 		return false
+	case tokenInf:
+		if tok.val[0] == '-' {
+			return math.Inf(-1)
+		}
+		return math.Inf(1)
+	case tokenNan:
+		return math.NaN()
 	case tokenInteger:
-		cleanedVal, err := cleanupNumberToken(tok.val)
-		if err != nil {
-			p.raiseError(tok, "%s", err)
+		cleanedVal := cleanupNumberToken(tok.val)
+		var err error
+		var val int64
+		if len(cleanedVal) >= 3 && cleanedVal[0] == '0' {
+			switch cleanedVal[1] {
+			case 'x':
+				err = hexNumberContainsInvalidUnderscore(tok.val)
+				if err != nil {
+					p.raiseError(tok, "%s", err)
+				}
+				val, err = strconv.ParseInt(cleanedVal[2:], 16, 64)
+			case 'o':
+				err = numberContainsInvalidUnderscore(tok.val)
+				if err != nil {
+					p.raiseError(tok, "%s", err)
+				}
+				val, err = strconv.ParseInt(cleanedVal[2:], 8, 64)
+			case 'b':
+				err = numberContainsInvalidUnderscore(tok.val)
+				if err != nil {
+					p.raiseError(tok, "%s", err)
+				}
+				val, err = strconv.ParseInt(cleanedVal[2:], 2, 64)
+			default:
+				panic("invalid base") // the lexer should catch this first
+			}
+		} else {
+			err = numberContainsInvalidUnderscore(tok.val)
+			if err != nil {
+				p.raiseError(tok, "%s", err)
+			}
+			val, err = strconv.ParseInt(cleanedVal, 10, 64)
 		}
-		val, err := strconv.ParseInt(cleanedVal, 10, 64)
 		if err != nil {
 			p.raiseError(tok, "%s", err)
 		}
 		return val
 	case tokenFloat:
-		cleanedVal, err := cleanupNumberToken(tok.val)
+		err := numberContainsInvalidUnderscore(tok.val)
 		if err != nil {
 			p.raiseError(tok, "%s", err)
 		}
+		cleanedVal := cleanupNumberToken(tok.val)
 		val, err := strconv.ParseFloat(cleanedVal, 64)
 		if err != nil {
 			p.raiseError(tok, "%s", err)
@@ -309,7 +355,7 @@ Loop:
 			}
 			p.getToken()
 		default:
-			p.raiseError(follow, "unexpected token type in inline table: %s", follow.typ.String())
+			p.raiseError(follow, "unexpected token type in inline table: %s", follow.String())
 		}
 		previous = follow
 	}
@@ -379,5 +425,6 @@ func parseToml(flow []token) *Tree {
 }
 
 func init() {
-	numberUnderscoreInvalidRegexp = regexp.MustCompile(`([^\d]_|_[^\d]|_$|^_)`)
+	numberUnderscoreInvalidRegexp = regexp.MustCompile(`([^\d]_|_[^\d])|_$|^_`)
+	hexNumberUnderscoreInvalidRegexp = regexp.MustCompile(`(^0x_)|([^\da-f]_|_[^\da-f])|_$|^_`)
 }

vendor/github.com/pelletier/go-toml/test.sh

 #!/bin/bash
 # fail out of the script if anything here fails
 set -e
+set -o pipefail
 
 # set the path to the present working directory
 export GOPATH=`pwd`
@@ -22,9 +23,6 @@ function git_clone() {
 # Remove potential previous runs
 rm -rf src test_program_bin toml-test
 
-# Run go vet
-go vet ./...
-
 go get github.com/pelletier/go-buffruneio
 go get github.com/davecgh/go-spew/spew
 go get gopkg.in/yaml.v2

vendor/github.com/pelletier/go-toml/token.go

@@ -23,6 +23,8 @@ const (
 	tokenTrue
 	tokenFalse
 	tokenFloat
+	tokenInf
+	tokenNan
 	tokenEqual
 	tokenLeftBracket
 	tokenRightBracket
@@ -55,6 +57,8 @@ var tokenTypeNames = []string{
 	"True",
 	"False",
 	"Float",
+	"Inf",
+	"NaN",
 	"=",
 	"[",
 	"]",

vendor/github.com/pelletier/go-toml/toml.go

@@ -11,14 +11,19 @@ import (
 )
 
 type tomlValue struct {
-	value    interface{} // string, int64, uint64, float64, bool, time.Time, [] of any of this list
-	position Position
+	value     interface{} // string, int64, uint64, float64, bool, time.Time, [] of any of this list
+	comment   string
+	commented bool
+	multiline bool
+	position  Position
 }
 
 // Tree is the result of the parsing of a TOML file.
 type Tree struct {
-	values   map[string]interface{} // string -> *tomlValue, *Tree, []*Tree
-	position Position
+	values    map[string]interface{} // string -> *tomlValue, *Tree, []*Tree
+	comment   string
+	commented bool
+	position  Position
 }
 
 func newTree() *Tree {
@@ -67,18 +72,15 @@ func (t *Tree) Keys() []string {
 }
 
 // Get the value at key in the Tree.
-// Key is a dot-separated path (e.g. a.b.c).
+// Key is a dot-separated path (e.g. a.b.c) without single/double quoted strings.
+// If you need to retrieve non-bare keys, use GetPath.
 // Returns nil if the path does not exist in the tree.
 // If keys is of length zero, the current tree is returned.
 func (t *Tree) Get(key string) interface{} {
 	if key == "" {
 		return t
 	}
-	comps, err := parseKey(key)
-	if err != nil {
-		return nil
-	}
-	return t.GetPath(comps)
+	return t.GetPath(strings.Split(key, "."))
 }
 
 // GetPath returns the element in the tree indicated by 'keys'.
@@ -174,17 +176,86 @@ func (t *Tree) GetDefault(key string, def interface{}) interface{} {
 	return val
 }
 
+// SetOptions arguments are supplied to the SetWithOptions and SetPathWithOptions functions to modify marshalling behaviour.
+// The default values within the struct are valid default options.
+type SetOptions struct {
+	Comment   string
+	Commented bool
+	Multiline bool
+}
+
+// SetWithOptions is the same as Set, but allows you to provide formatting
+// instructions to the key, that will be used by Marshal().
+func (t *Tree) SetWithOptions(key string, opts SetOptions, value interface{}) {
+	t.SetPathWithOptions(strings.Split(key, "."), opts, value)
+}
+
+// SetPathWithOptions is the same as SetPath, but allows you to provide
+// formatting instructions to the key, that will be reused by Marshal().
+func (t *Tree) SetPathWithOptions(keys []string, opts SetOptions, value interface{}) {
+	subtree := t
+	for _, intermediateKey := range keys[:len(keys)-1] {
+		nextTree, exists := subtree.values[intermediateKey]
+		if !exists {
+			nextTree = newTree()
+			subtree.values[intermediateKey] = nextTree // add new element here
+		}
+		switch node := nextTree.(type) {
+		case *Tree:
+			subtree = node
+		case []*Tree:
+			// go to most recent element
+			if len(node) == 0 {
+				// create element if it does not exist
+				subtree.values[intermediateKey] = append(node, newTree())
+			}
+			subtree = node[len(node)-1]
+		}
+	}
+
+	var toInsert interface{}
+
+	switch value.(type) {
+	case *Tree:
+		tt := value.(*Tree)
+		tt.comment = opts.Comment
+		toInsert = value
+	case []*Tree:
+		toInsert = value
+	case *tomlValue:
+		tt := value.(*tomlValue)
+		tt.comment = opts.Comment
+		toInsert = tt
+	default:
+		toInsert = &tomlValue{value: value, comment: opts.Comment, commented: opts.Commented, multiline: opts.Multiline}
+	}
+
+	subtree.values[keys[len(keys)-1]] = toInsert
+}
+
 // Set an element in the tree.
 // Key is a dot-separated path (e.g. a.b.c).
 // Creates all necessary intermediate trees, if needed.
 func (t *Tree) Set(key string, value interface{}) {
-	t.SetPath(strings.Split(key, "."), value)
+	t.SetWithComment(key, "", false, value)
+}
+
+// SetWithComment is the same as Set, but allows you to provide comment
+// information to the key, that will be reused by Marshal().
+func (t *Tree) SetWithComment(key string, comment string, commented bool, value interface{}) {
+	t.SetPathWithComment(strings.Split(key, "."), comment, commented, value)
 }
 
 // SetPath sets an element in the tree.
 // Keys is an array of path elements (e.g. {"a","b","c"}).
 // Creates all necessary intermediate trees, if needed.
 func (t *Tree) SetPath(keys []string, value interface{}) {
+	t.SetPathWithComment(keys, "", false, value)
+}
+
+// SetPathWithComment is the same as SetPath, but allows you to provide comment
+// information to the key, that will be reused by Marshal().
+func (t *Tree) SetPathWithComment(keys []string, comment string, commented bool, value interface{}) {
 	subtree := t
 	for _, intermediateKey := range keys[:len(keys)-1] {
 		nextTree, exists := subtree.values[intermediateKey]
@@ -209,13 +280,17 @@ func (t *Tree) SetPath(keys []string, value interface{}) {
 
 	switch value.(type) {
 	case *Tree:
+		tt := value.(*Tree)
+		tt.comment = comment
 		toInsert = value
 	case []*Tree:
 		toInsert = value
 	case *tomlValue:
-		toInsert = value
+		tt := value.(*tomlValue)
+		tt.comment = comment
+		toInsert = tt
 	default:
-		toInsert = &tomlValue{value: value}
+		toInsert = &tomlValue{value: value, comment: comment, commented: commented}
 	}
 
 	subtree.values[keys[len(keys)-1]] = toInsert

vendor/github.com/pelletier/go-toml/tomltree_create.go

@@ -104,7 +104,7 @@ func sliceToTree(object interface{}) (interface{}, error) {
 		}
 		arrayValue = reflect.Append(arrayValue, reflect.ValueOf(simpleValue))
 	}
-	return &tomlValue{arrayValue.Interface(), Position{}}, nil
+	return &tomlValue{value: arrayValue.Interface(), position: Position{}}, nil
 }
 
 func toTree(object interface{}) (interface{}, error) {
@@ -127,7 +127,7 @@ func toTree(object interface{}) (interface{}, error) {
 			}
 			values[key.String()] = newValue
 		}
-		return &Tree{values, Position{}}, nil
+		return &Tree{values: values, position: Position{}}, nil
 	}
 
 	if value.Kind() == reflect.Array || value.Kind() == reflect.Slice {
@@ -138,5 +138,5 @@ func toTree(object interface{}) (interface{}, error) {
 	if err != nil {
 		return nil, err
 	}
-	return &tomlValue{simpleValue, Position{}}, nil
+	return &tomlValue{value: simpleValue, position: Position{}}, nil
 }

vendor/github.com/pelletier/go-toml/tomltree_write.go

@@ -12,7 +12,41 @@ import (
 	"time"
 )
 
-// encodes a string to a TOML-compliant string value
+// Encodes a string to a TOML-compliant multi-line string value
+// This function is a clone of the existing encodeTomlString function, except that whitespace characters
+// are preserved. Quotation marks and backslashes are also not escaped.
+func encodeMultilineTomlString(value string) string {
+	var b bytes.Buffer
+
+	for _, rr := range value {
+		switch rr {
+		case '\b':
+			b.WriteString(`\b`)
+		case '\t':
+			b.WriteString("\t")
+		case '\n':
+			b.WriteString("\n")
+		case '\f':
+			b.WriteString(`\f`)
+		case '\r':
+			b.WriteString("\r")
+		case '"':
+			b.WriteString(`"`)
+		case '\\':
+			b.WriteString(`\`)
+		default:
+			intRr := uint16(rr)
+			if intRr < 0x001F {
+				b.WriteString(fmt.Sprintf("\\u%0.4X", intRr))
+			} else {
+				b.WriteRune(rr)
+			}
+		}
+	}
+	return b.String()
+}
+
+// Encodes a string to a TOML-compliant string value
 func encodeTomlString(value string) string {
 	var b bytes.Buffer
 
@@ -44,7 +78,16 @@ func encodeTomlString(value string) string {
 	return b.String()
 }
 
-func tomlValueStringRepresentation(v interface{}) (string, error) {
+func tomlValueStringRepresentation(v interface{}, indent string, arraysOneElementPerLine bool) (string, error) {
+	// this interface check is added to dereference the change made in the writeTo function.
+	// That change was made to allow this function to see formatting options.
+	tv, ok := v.(*tomlValue)
+	if ok {
+		v = tv.value
+	} else {
+		tv = &tomlValue{}
+	}
+
 	switch value := v.(type) {
 	case uint64:
 		return strconv.FormatUint(value, 10), nil
@@ -54,14 +97,17 @@ func tomlValueStringRepresentation(v interface{}) (string, error) {
 		// Ensure a round float does contain a decimal point. Otherwise feeding
 		// the output back to the parser would convert to an integer.
 		if math.Trunc(value) == value {
-			return strconv.FormatFloat(value, 'f', 1, 32), nil
+			return strings.ToLower(strconv.FormatFloat(value, 'f', 1, 32)), nil
 		}
-		return strconv.FormatFloat(value, 'f', -1, 32), nil
+		return strings.ToLower(strconv.FormatFloat(value, 'f', -1, 32)), nil
 	case string:
+		if tv.multiline {
+			return "\"\"\"\n" + encodeMultilineTomlString(value) + "\"\"\"", nil
+		}
 		return "\"" + encodeTomlString(value) + "\"", nil
 	case []byte:
 		b, _ := v.([]byte)
-		return tomlValueStringRepresentation(string(b))
+		return tomlValueStringRepresentation(string(b), indent, arraysOneElementPerLine)
 	case bool:
 		if value {
 			return "true", nil
@@ -76,21 +122,38 @@ func tomlValueStringRepresentation(v interface{}) (string, error) {
 	rv := reflect.ValueOf(v)
 
 	if rv.Kind() == reflect.Slice {
-		values := []string{}
+		var values []string
 		for i := 0; i < rv.Len(); i++ {
 			item := rv.Index(i).Interface()
-			itemRepr, err := tomlValueStringRepresentation(item)
+			itemRepr, err := tomlValueStringRepresentation(item, indent, arraysOneElementPerLine)
 			if err != nil {
 				return "", err
 			}
 			values = append(values, itemRepr)
 		}
+		if arraysOneElementPerLine && len(values) > 1 {
+			stringBuffer := bytes.Buffer{}
+			valueIndent := indent + `  ` // TODO: move that to a shared encoder state
+
+			stringBuffer.WriteString("[\n")
+
+			for _, value := range values {
+				stringBuffer.WriteString(valueIndent)
+				stringBuffer.WriteString(value)
+				stringBuffer.WriteString(`,`)
+				stringBuffer.WriteString("\n")
+			}
+
+			stringBuffer.WriteString(indent + "]")
+
+			return stringBuffer.String(), nil
+		}
 		return "[" + strings.Join(values, ",") + "]", nil
 	}
 	return "", fmt.Errorf("unsupported value type %T: %v", v, v)
 }
 
-func (t *Tree) writeTo(w io.Writer, indent, keyspace string, bytesCount int64) (int64, error) {
+func (t *Tree) writeTo(w io.Writer, indent, keyspace string, bytesCount int64, arraysOneElementPerLine bool) (int64, error) {
 	simpleValuesKeys := make([]string, 0)
 	complexValuesKeys := make([]string, 0)
 
@@ -113,12 +176,29 @@ func (t *Tree) writeTo(w io.Writer, indent, keyspace string, bytesCount int64) (
 			return bytesCount, fmt.Errorf("invalid value type at %s: %T", k, t.values[k])
 		}
 
-		repr, err := tomlValueStringRepresentation(v.value)
+		repr, err := tomlValueStringRepresentation(v, indent, arraysOneElementPerLine)
 		if err != nil {
 			return bytesCount, err
 		}
 
-		writtenBytesCount, err := writeStrings(w, indent, k, " = ", repr, "\n")
+		if v.comment != "" {
+			comment := strings.Replace(v.comment, "\n", "\n"+indent+"#", -1)
+			start := "# "
+			if strings.HasPrefix(comment, "#") {
+				start = ""
+			}
+			writtenBytesCountComment, errc := writeStrings(w, "\n", indent, start, comment, "\n")
+			bytesCount += int64(writtenBytesCountComment)
+			if errc != nil {
+				return bytesCount, errc
+			}
+		}
+
+		var commented string
+		if v.commented {
+			commented = "# "
+		}
+		writtenBytesCount, err := writeStrings(w, indent, commented, k, " = ", repr, "\n")
 		bytesCount += int64(writtenBytesCount)
 		if err != nil {
 			return bytesCount, err
@@ -132,28 +212,48 @@ func (t *Tree) writeTo(w io.Writer, indent, keyspace string, bytesCount int64) (
 		if keyspace != "" {
 			combinedKey = keyspace + "." + combinedKey
 		}
+		var commented string
+		if t.commented {
+			commented = "# "
+		}
 
 		switch node := v.(type) {
 		// node has to be of those two types given how keys are sorted above
 		case *Tree:
-			writtenBytesCount, err := writeStrings(w, "\n", indent, "[", combinedKey, "]\n")
+			tv, ok := t.values[k].(*Tree)
+			if !ok {
+				return bytesCount, fmt.Errorf("invalid value type at %s: %T", k, t.values[k])
+			}
+			if tv.comment != "" {
+				comment := strings.Replace(tv.comment, "\n", "\n"+indent+"#", -1)
+				start := "# "
+				if strings.HasPrefix(comment, "#") {
+					start = ""
+				}
+				writtenBytesCountComment, errc := writeStrings(w, "\n", indent, start, comment)
+				bytesCount += int64(writtenBytesCountComment)
+				if errc != nil {
+					return bytesCount, errc
+				}
+			}
+			writtenBytesCount, err := writeStrings(w, "\n", indent, commented, "[", combinedKey, "]\n")
 			bytesCount += int64(writtenBytesCount)
 			if err != nil {
 				return bytesCount, err
 			}
-			bytesCount, err = node.writeTo(w, indent+"  ", combinedKey, bytesCount)
+			bytesCount, err = node.writeTo(w, indent+"  ", combinedKey, bytesCount, arraysOneElementPerLine)
 			if err != nil {
 				return bytesCount, err
 			}
 		case []*Tree:
 			for _, subTree := range node {
-				writtenBytesCount, err := writeStrings(w, "\n", indent, "[[", combinedKey, "]]\n")
+				writtenBytesCount, err := writeStrings(w, "\n", indent, commented, "[[", combinedKey, "]]\n")
 				bytesCount += int64(writtenBytesCount)
 				if err != nil {
 					return bytesCount, err
 				}
 
-				bytesCount, err = subTree.writeTo(w, indent+"  ", combinedKey, bytesCount)
+				bytesCount, err = subTree.writeTo(w, indent+"  ", combinedKey, bytesCount, arraysOneElementPerLine)
 				if err != nil {
 					return bytesCount, err
 				}
@@ -179,7 +279,7 @@ func writeStrings(w io.Writer, s ...string) (int, error) {
 // WriteTo encode the Tree as Toml and writes it to the writer w.
 // Returns the number of bytes written in case of success, or an error if anything happened.
 func (t *Tree) WriteTo(w io.Writer) (int64, error) {
-	return t.writeTo(w, "", "", 0)
+	return t.writeTo(w, "", "", 0, false)
 }
 
 // ToTomlString generates a human-readable representation of the current tree.