lego/vendor/github.com/BurntSushi/toml/parse.go
Ludovic Fernandez 62fea05e21
Automatic generation of documentation (#818)
* generate a detailed CLI help
* generate a documentation site
* new readme
2019-03-08 19:47:06 +01:00

592 lines
15 KiB
Go

package toml
import (
"fmt"
"strconv"
"strings"
"time"
"unicode"
"unicode/utf8"
)
type parser struct {
mapping map[string]interface{}
types map[string]tomlType
lx *lexer
// A list of keys in the order that they appear in the TOML data.
ordered []Key
// the full key for the current hash in scope
context Key
// the base key name for everything except hashes
currentKey string
// rough approximation of line number
approxLine int
// A map of 'key.group.names' to whether they were created implicitly.
implicits map[string]bool
}
type parseError string
func (pe parseError) Error() string {
return string(pe)
}
func parse(data string) (p *parser, err error) {
defer func() {
if r := recover(); r != nil {
var ok bool
if err, ok = r.(parseError); ok {
return
}
panic(r)
}
}()
p = &parser{
mapping: make(map[string]interface{}),
types: make(map[string]tomlType),
lx: lex(data),
ordered: make([]Key, 0),
implicits: make(map[string]bool),
}
for {
item := p.next()
if item.typ == itemEOF {
break
}
p.topLevel(item)
}
return p, nil
}
func (p *parser) panicf(format string, v ...interface{}) {
msg := fmt.Sprintf("Near line %d (last key parsed '%s'): %s",
p.approxLine, p.current(), fmt.Sprintf(format, v...))
panic(parseError(msg))
}
func (p *parser) next() item {
it := p.lx.nextItem()
if it.typ == itemError {
p.panicf("%s", it.val)
}
return it
}
func (p *parser) bug(format string, v ...interface{}) {
panic(fmt.Sprintf("BUG: "+format+"\n\n", v...))
}
func (p *parser) expect(typ itemType) item {
it := p.next()
p.assertEqual(typ, it.typ)
return it
}
func (p *parser) assertEqual(expected, got itemType) {
if expected != got {
p.bug("Expected '%s' but got '%s'.", expected, got)
}
}
func (p *parser) topLevel(item item) {
switch item.typ {
case itemCommentStart:
p.approxLine = item.line
p.expect(itemText)
case itemTableStart:
kg := p.next()
p.approxLine = kg.line
var key Key
for ; kg.typ != itemTableEnd && kg.typ != itemEOF; kg = p.next() {
key = append(key, p.keyString(kg))
}
p.assertEqual(itemTableEnd, kg.typ)
p.establishContext(key, false)
p.setType("", tomlHash)
p.ordered = append(p.ordered, key)
case itemArrayTableStart:
kg := p.next()
p.approxLine = kg.line
var key Key
for ; kg.typ != itemArrayTableEnd && kg.typ != itemEOF; kg = p.next() {
key = append(key, p.keyString(kg))
}
p.assertEqual(itemArrayTableEnd, kg.typ)
p.establishContext(key, true)
p.setType("", tomlArrayHash)
p.ordered = append(p.ordered, key)
case itemKeyStart:
kname := p.next()
p.approxLine = kname.line
p.currentKey = p.keyString(kname)
val, typ := p.value(p.next())
p.setValue(p.currentKey, val)
p.setType(p.currentKey, typ)
p.ordered = append(p.ordered, p.context.add(p.currentKey))
p.currentKey = ""
default:
p.bug("Unexpected type at top level: %s", item.typ)
}
}
// Gets a string for a key (or part of a key in a table name).
func (p *parser) keyString(it item) string {
switch it.typ {
case itemText:
return it.val
case itemString, itemMultilineString,
itemRawString, itemRawMultilineString:
s, _ := p.value(it)
return s.(string)
default:
p.bug("Unexpected key type: %s", it.typ)
panic("unreachable")
}
}
// value translates an expected value from the lexer into a Go value wrapped
// as an empty interface.
func (p *parser) value(it item) (interface{}, tomlType) {
switch it.typ {
case itemString:
return p.replaceEscapes(it.val), p.typeOfPrimitive(it)
case itemMultilineString:
trimmed := stripFirstNewline(stripEscapedWhitespace(it.val))
return p.replaceEscapes(trimmed), p.typeOfPrimitive(it)
case itemRawString:
return it.val, p.typeOfPrimitive(it)
case itemRawMultilineString:
return stripFirstNewline(it.val), p.typeOfPrimitive(it)
case itemBool:
switch it.val {
case "true":
return true, p.typeOfPrimitive(it)
case "false":
return false, p.typeOfPrimitive(it)
}
p.bug("Expected boolean value, but got '%s'.", it.val)
case itemInteger:
if !numUnderscoresOK(it.val) {
p.panicf("Invalid integer %q: underscores must be surrounded by digits",
it.val)
}
val := strings.Replace(it.val, "_", "", -1)
num, err := strconv.ParseInt(val, 10, 64)
if err != nil {
// Distinguish integer values. Normally, it'd be a bug if the lexer
// provides an invalid integer, but it's possible that the number is
// out of range of valid values (which the lexer cannot determine).
// So mark the former as a bug but the latter as a legitimate user
// error.
if e, ok := err.(*strconv.NumError); ok &&
e.Err == strconv.ErrRange {
p.panicf("Integer '%s' is out of the range of 64-bit "+
"signed integers.", it.val)
} else {
p.bug("Expected integer value, but got '%s'.", it.val)
}
}
return num, p.typeOfPrimitive(it)
case itemFloat:
parts := strings.FieldsFunc(it.val, func(r rune) bool {
switch r {
case '.', 'e', 'E':
return true
}
return false
})
for _, part := range parts {
if !numUnderscoresOK(part) {
p.panicf("Invalid float %q: underscores must be "+
"surrounded by digits", it.val)
}
}
if !numPeriodsOK(it.val) {
// As a special case, numbers like '123.' or '1.e2',
// which are valid as far as Go/strconv are concerned,
// must be rejected because TOML says that a fractional
// part consists of '.' followed by 1+ digits.
p.panicf("Invalid float %q: '.' must be followed "+
"by one or more digits", it.val)
}
val := strings.Replace(it.val, "_", "", -1)
num, err := strconv.ParseFloat(val, 64)
if err != nil {
if e, ok := err.(*strconv.NumError); ok &&
e.Err == strconv.ErrRange {
p.panicf("Float '%s' is out of the range of 64-bit "+
"IEEE-754 floating-point numbers.", it.val)
} else {
p.panicf("Invalid float value: %q", it.val)
}
}
return num, p.typeOfPrimitive(it)
case itemDatetime:
var t time.Time
var ok bool
var err error
for _, format := range []string{
"2006-01-02T15:04:05Z07:00",
"2006-01-02T15:04:05",
"2006-01-02",
} {
t, err = time.ParseInLocation(format, it.val, time.Local)
if err == nil {
ok = true
break
}
}
if !ok {
p.panicf("Invalid TOML Datetime: %q.", it.val)
}
return t, p.typeOfPrimitive(it)
case itemArray:
array := make([]interface{}, 0)
types := make([]tomlType, 0)
for it = p.next(); it.typ != itemArrayEnd; it = p.next() {
if it.typ == itemCommentStart {
p.expect(itemText)
continue
}
val, typ := p.value(it)
array = append(array, val)
types = append(types, typ)
}
return array, p.typeOfArray(types)
case itemInlineTableStart:
var (
hash = make(map[string]interface{})
outerContext = p.context
outerKey = p.currentKey
)
p.context = append(p.context, p.currentKey)
p.currentKey = ""
for it := p.next(); it.typ != itemInlineTableEnd; it = p.next() {
if it.typ != itemKeyStart {
p.bug("Expected key start but instead found %q, around line %d",
it.val, p.approxLine)
}
if it.typ == itemCommentStart {
p.expect(itemText)
continue
}
// retrieve key
k := p.next()
p.approxLine = k.line
kname := p.keyString(k)
// retrieve value
p.currentKey = kname
val, typ := p.value(p.next())
// make sure we keep metadata up to date
p.setType(kname, typ)
p.ordered = append(p.ordered, p.context.add(p.currentKey))
hash[kname] = val
}
p.context = outerContext
p.currentKey = outerKey
return hash, tomlHash
}
p.bug("Unexpected value type: %s", it.typ)
panic("unreachable")
}
// numUnderscoresOK checks whether each underscore in s is surrounded by
// characters that are not underscores.
func numUnderscoresOK(s string) bool {
accept := false
for _, r := range s {
if r == '_' {
if !accept {
return false
}
accept = false
continue
}
accept = true
}
return accept
}
// numPeriodsOK checks whether every period in s is followed by a digit.
func numPeriodsOK(s string) bool {
period := false
for _, r := range s {
if period && !isDigit(r) {
return false
}
period = r == '.'
}
return !period
}
// establishContext sets the current context of the parser,
// where the context is either a hash or an array of hashes. Which one is
// set depends on the value of the `array` parameter.
//
// Establishing the context also makes sure that the key isn't a duplicate, and
// will create implicit hashes automatically.
func (p *parser) establishContext(key Key, array bool) {
var ok bool
// Always start at the top level and drill down for our context.
hashContext := p.mapping
keyContext := make(Key, 0)
// We only need implicit hashes for key[0:-1]
for _, k := range key[0 : len(key)-1] {
_, ok = hashContext[k]
keyContext = append(keyContext, k)
// No key? Make an implicit hash and move on.
if !ok {
p.addImplicit(keyContext)
hashContext[k] = make(map[string]interface{})
}
// If the hash context is actually an array of tables, then set
// the hash context to the last element in that array.
//
// Otherwise, it better be a table, since this MUST be a key group (by
// virtue of it not being the last element in a key).
switch t := hashContext[k].(type) {
case []map[string]interface{}:
hashContext = t[len(t)-1]
case map[string]interface{}:
hashContext = t
default:
p.panicf("Key '%s' was already created as a hash.", keyContext)
}
}
p.context = keyContext
if array {
// If this is the first element for this array, then allocate a new
// list of tables for it.
k := key[len(key)-1]
if _, ok := hashContext[k]; !ok {
hashContext[k] = make([]map[string]interface{}, 0, 5)
}
// Add a new table. But make sure the key hasn't already been used
// for something else.
if hash, ok := hashContext[k].([]map[string]interface{}); ok {
hashContext[k] = append(hash, make(map[string]interface{}))
} else {
p.panicf("Key '%s' was already created and cannot be used as "+
"an array.", keyContext)
}
} else {
p.setValue(key[len(key)-1], make(map[string]interface{}))
}
p.context = append(p.context, key[len(key)-1])
}
// setValue sets the given key to the given value in the current context.
// It will make sure that the key hasn't already been defined, account for
// implicit key groups.
func (p *parser) setValue(key string, value interface{}) {
var tmpHash interface{}
var ok bool
hash := p.mapping
keyContext := make(Key, 0)
for _, k := range p.context {
keyContext = append(keyContext, k)
if tmpHash, ok = hash[k]; !ok {
p.bug("Context for key '%s' has not been established.", keyContext)
}
switch t := tmpHash.(type) {
case []map[string]interface{}:
// The context is a table of hashes. Pick the most recent table
// defined as the current hash.
hash = t[len(t)-1]
case map[string]interface{}:
hash = t
default:
p.bug("Expected hash to have type 'map[string]interface{}', but "+
"it has '%T' instead.", tmpHash)
}
}
keyContext = append(keyContext, key)
if _, ok := hash[key]; ok {
// Typically, if the given key has already been set, then we have
// to raise an error since duplicate keys are disallowed. However,
// it's possible that a key was previously defined implicitly. In this
// case, it is allowed to be redefined concretely. (See the
// `tests/valid/implicit-and-explicit-after.toml` test in `toml-test`.)
//
// But we have to make sure to stop marking it as an implicit. (So that
// another redefinition provokes an error.)
//
// Note that since it has already been defined (as a hash), we don't
// want to overwrite it. So our business is done.
if p.isImplicit(keyContext) {
p.removeImplicit(keyContext)
return
}
// Otherwise, we have a concrete key trying to override a previous
// key, which is *always* wrong.
p.panicf("Key '%s' has already been defined.", keyContext)
}
hash[key] = value
}
// setType sets the type of a particular value at a given key.
// It should be called immediately AFTER setValue.
//
// Note that if `key` is empty, then the type given will be applied to the
// current context (which is either a table or an array of tables).
func (p *parser) setType(key string, typ tomlType) {
keyContext := make(Key, 0, len(p.context)+1)
for _, k := range p.context {
keyContext = append(keyContext, k)
}
if len(key) > 0 { // allow type setting for hashes
keyContext = append(keyContext, key)
}
p.types[keyContext.String()] = typ
}
// addImplicit sets the given Key as having been created implicitly.
func (p *parser) addImplicit(key Key) {
p.implicits[key.String()] = true
}
// removeImplicit stops tagging the given key as having been implicitly
// created.
func (p *parser) removeImplicit(key Key) {
p.implicits[key.String()] = false
}
// isImplicit returns true if the key group pointed to by the key was created
// implicitly.
func (p *parser) isImplicit(key Key) bool {
return p.implicits[key.String()]
}
// current returns the full key name of the current context.
func (p *parser) current() string {
if len(p.currentKey) == 0 {
return p.context.String()
}
if len(p.context) == 0 {
return p.currentKey
}
return fmt.Sprintf("%s.%s", p.context, p.currentKey)
}
func stripFirstNewline(s string) string {
if len(s) == 0 || s[0] != '\n' {
return s
}
return s[1:]
}
func stripEscapedWhitespace(s string) string {
esc := strings.Split(s, "\\\n")
if len(esc) > 1 {
for i := 1; i < len(esc); i++ {
esc[i] = strings.TrimLeftFunc(esc[i], unicode.IsSpace)
}
}
return strings.Join(esc, "")
}
func (p *parser) replaceEscapes(str string) string {
var replaced []rune
s := []byte(str)
r := 0
for r < len(s) {
if s[r] != '\\' {
c, size := utf8.DecodeRune(s[r:])
r += size
replaced = append(replaced, c)
continue
}
r += 1
if r >= len(s) {
p.bug("Escape sequence at end of string.")
return ""
}
switch s[r] {
default:
p.bug("Expected valid escape code after \\, but got %q.", s[r])
return ""
case 'b':
replaced = append(replaced, rune(0x0008))
r += 1
case 't':
replaced = append(replaced, rune(0x0009))
r += 1
case 'n':
replaced = append(replaced, rune(0x000A))
r += 1
case 'f':
replaced = append(replaced, rune(0x000C))
r += 1
case 'r':
replaced = append(replaced, rune(0x000D))
r += 1
case '"':
replaced = append(replaced, rune(0x0022))
r += 1
case '\\':
replaced = append(replaced, rune(0x005C))
r += 1
case 'u':
// At this point, we know we have a Unicode escape of the form
// `uXXXX` at [r, r+5). (Because the lexer guarantees this
// for us.)
escaped := p.asciiEscapeToUnicode(s[r+1 : r+5])
replaced = append(replaced, escaped)
r += 5
case 'U':
// At this point, we know we have a Unicode escape of the form
// `uXXXX` at [r, r+9). (Because the lexer guarantees this
// for us.)
escaped := p.asciiEscapeToUnicode(s[r+1 : r+9])
replaced = append(replaced, escaped)
r += 9
}
}
return string(replaced)
}
func (p *parser) asciiEscapeToUnicode(bs []byte) rune {
s := string(bs)
hex, err := strconv.ParseUint(strings.ToLower(s), 16, 32)
if err != nil {
p.bug("Could not parse '%s' as a hexadecimal number, but the "+
"lexer claims it's OK: %s", s, err)
}
if !utf8.ValidRune(rune(hex)) {
p.panicf("Escaped character '\\u%s' is not valid UTF-8.", s)
}
return rune(hex)
}
func isStringType(ty itemType) bool {
return ty == itemString || ty == itemMultilineString ||
ty == itemRawString || ty == itemRawMultilineString
}