gjson/gjson.go

1951 lines
42 KiB
Go

// Package gjson provides searching for json strings.
package gjson
import (
"reflect"
"strconv"
"unicode/utf16"
"unicode/utf8"
"unsafe"
"github.com/tidwall/match"
)
// Type is Result type
type Type int
const (
// Null is a null json value
Null Type = iota
// False is a json false boolean
False
// Number is json number
Number
// String is a json string
String
// True is a json true boolean
True
// JSON is a raw block of JSON
JSON
)
// String returns a string representation of the type.
func (t Type) String() string {
switch t {
default:
return ""
case Null:
return "Null"
case False:
return "False"
case Number:
return "Number"
case String:
return "String"
case True:
return "True"
case JSON:
return "JSON"
}
}
// Result represents a json value that is returned from Get().
type Result struct {
// Type is the json type
Type Type
// Raw is the raw json
Raw string
// Str is the json string
Str string
// Num is the json number
Num float64
// Index of raw value in original json, zero means index unknown
Index int
}
// String returns a string representation of the value.
func (t Result) String() string {
switch t.Type {
default:
return "null"
case False:
return "false"
case Number:
return strconv.FormatFloat(t.Num, 'f', -1, 64)
case String:
return t.Str
case JSON:
return t.Raw
case True:
return "true"
}
}
// Bool returns an boolean representation.
func (t Result) Bool() bool {
switch t.Type {
default:
return false
case True:
return true
case String:
return t.Str != "" && t.Str != "0"
case Number:
return t.Num != 0
}
}
// Int returns an integer representation.
func (t Result) Int() int64 {
switch t.Type {
default:
return 0
case True:
return 1
case String:
n, _ := strconv.ParseInt(t.Str, 10, 64)
return n
case Number:
return int64(t.Num)
}
}
// Uint returns an unsigned integer representation.
func (t Result) Uint() uint64 {
switch t.Type {
default:
return 0
case True:
return 1
case String:
n, _ := strconv.ParseUint(t.Str, 10, 64)
return n
case Number:
return uint64(t.Num)
}
}
// Float returns an float64 representation.
func (t Result) Float() float64 {
switch t.Type {
default:
return 0
case True:
return 1
case String:
n, _ := strconv.ParseFloat(t.Str, 64)
return n
case Number:
return t.Num
}
}
// Array returns back an array of values.
// If the result represents a non-existent value, then an empty array will be returned.
// If the result is not a JSON array, the return value will be an array containing one result.
func (t Result) Array() []Result {
if !t.Exists() {
return nil
}
if t.Type != JSON {
return []Result{t}
}
r := t.arrayOrMap('[', false)
return r.a
}
// ForEach iterates through values.
// If the result represents a non-existent value, then no values will be iterated.
// If the result is an Object, the iterator will pass the key and value of each item.
// If the result is an Array, the iterator will only pass the value of each item.
// If the result is not a JSON array or object, the iterator will pass back one value equal to the result.
func (t Result) ForEach(iterator func(key, value Result) bool) {
if !t.Exists() {
return
}
if t.Type != JSON {
iterator(Result{}, t)
return
}
json := t.Raw
var keys bool
var i int
var key, value Result
for ; i < len(json); i++ {
if json[i] == '{' {
i++
key.Type = String
keys = true
break
} else if json[i] == '[' {
i++
break
}
if json[i] > ' ' {
return
}
}
var str string
var vesc bool
var ok bool
for ; i < len(json); i++ {
if keys {
if json[i] != '"' {
continue
}
s := i
i, str, vesc, ok = parseString(json, i+1)
if !ok {
return
}
if vesc {
key.Str = unescape(str[1 : len(str)-1])
} else {
key.Str = str[1 : len(str)-1]
}
key.Raw = str
key.Index = s
}
for ; i < len(json); i++ {
if json[i] <= ' ' || json[i] == ',' || json[i] == ':' {
continue
}
break
}
s := i
i, value, ok = parseAny(json, i, true)
if !ok {
return
}
value.Index = s
if !iterator(key, value) {
return
}
}
}
// Map returns back an map of values. The result should be a JSON array.
func (t Result) Map() map[string]Result {
if t.Type != JSON {
return map[string]Result{}
}
r := t.arrayOrMap('{', false)
return r.o
}
// Get searches result for the specified path.
// The result should be a JSON array or object.
func (t Result) Get(path string) Result {
return Get(t.Raw, path)
}
type arrayOrMapResult struct {
a []Result
ai []interface{}
o map[string]Result
oi map[string]interface{}
vc byte
}
func (t Result) arrayOrMap(vc byte, valueize bool) (r arrayOrMapResult) {
var json = t.Raw
var i int
var value Result
var count int
var key Result
if vc == 0 {
for ; i < len(json); i++ {
if json[i] == '{' || json[i] == '[' {
r.vc = json[i]
i++
break
}
if json[i] > ' ' {
goto end
}
}
} else {
for ; i < len(json); i++ {
if json[i] == vc {
i++
break
}
if json[i] > ' ' {
goto end
}
}
r.vc = vc
}
if r.vc == '{' {
if valueize {
r.oi = make(map[string]interface{})
} else {
r.o = make(map[string]Result)
}
} else {
if valueize {
r.ai = make([]interface{}, 0)
} else {
r.a = make([]Result, 0)
}
}
for ; i < len(json); i++ {
if json[i] <= ' ' {
continue
}
// get next value
if json[i] == ']' || json[i] == '}' {
break
}
switch json[i] {
default:
if (json[i] >= '0' && json[i] <= '9') || json[i] == '-' {
value.Type = Number
value.Raw, value.Num = tonum(json[i:])
} else {
continue
}
case '{', '[':
value.Type = JSON
value.Raw = squash(json[i:])
case 'n':
value.Type = Null
value.Raw = tolit(json[i:])
case 't':
value.Type = True
value.Raw = tolit(json[i:])
case 'f':
value.Type = False
value.Raw = tolit(json[i:])
case '"':
value.Type = String
value.Raw, value.Str = tostr(json[i:])
}
i += len(value.Raw) - 1
if r.vc == '{' {
if count%2 == 0 {
key = value
} else {
if valueize {
r.oi[key.Str] = value.Value()
} else {
r.o[key.Str] = value
}
}
count++
} else {
if valueize {
r.ai = append(r.ai, value.Value())
} else {
r.a = append(r.a, value)
}
}
}
end:
return
}
// Parse parses the json and returns a result.
func Parse(json string) Result {
var value Result
for i := 0; i < len(json); i++ {
if json[i] == '{' || json[i] == '[' {
value.Type = JSON
value.Raw = json[i:] // just take the entire raw
break
}
if json[i] <= ' ' {
continue
}
switch json[i] {
default:
if (json[i] >= '0' && json[i] <= '9') || json[i] == '-' {
value.Type = Number
value.Raw, value.Num = tonum(json[i:])
} else {
return Result{}
}
case 'n':
value.Type = Null
value.Raw = tolit(json[i:])
case 't':
value.Type = True
value.Raw = tolit(json[i:])
case 'f':
value.Type = False
value.Raw = tolit(json[i:])
case '"':
value.Type = String
value.Raw, value.Str = tostr(json[i:])
}
break
}
return value
}
// ParseBytes parses the json and returns a result.
// If working with bytes, this method preferred over Parse(string(data))
func ParseBytes(json []byte) Result {
return Parse(string(json))
}
func squash(json string) string {
// expects that the lead character is a '[' or '{'
// squash the value, ignoring all nested arrays and objects.
// the first '[' or '{' has already been read
depth := 1
for i := 1; i < len(json); i++ {
if json[i] >= '"' && json[i] <= '}' {
switch json[i] {
case '"':
i++
s2 := i
for ; i < len(json); i++ {
if json[i] > '\\' {
continue
}
if json[i] == '"' {
// look for an escaped slash
if json[i-1] == '\\' {
n := 0
for j := i - 2; j > s2-1; j-- {
if json[j] != '\\' {
break
}
n++
}
if n%2 == 0 {
continue
}
}
break
}
}
case '{', '[':
depth++
case '}', ']':
depth--
if depth == 0 {
return json[:i+1]
}
}
}
}
return json
}
func tonum(json string) (raw string, num float64) {
for i := 1; i < len(json); i++ {
// less than dash might have valid characters
if json[i] <= '-' {
if json[i] <= ' ' || json[i] == ',' {
// break on whitespace and comma
raw = json[:i]
num, _ = strconv.ParseFloat(raw, 64)
return
}
// could be a '+' or '-'. let's assume so.
continue
}
if json[i] < ']' {
// probably a valid number
continue
}
if json[i] == 'e' || json[i] == 'E' {
// allow for exponential numbers
continue
}
// likely a ']' or '}'
raw = json[:i]
num, _ = strconv.ParseFloat(raw, 64)
return
}
raw = json
num, _ = strconv.ParseFloat(raw, 64)
return
}
func tolit(json string) (raw string) {
for i := 1; i < len(json); i++ {
if json[i] <= 'a' || json[i] >= 'z' {
return json[:i]
}
}
return json
}
func tostr(json string) (raw string, str string) {
// expects that the lead character is a '"'
for i := 1; i < len(json); i++ {
if json[i] > '\\' {
continue
}
if json[i] == '"' {
return json[:i+1], json[1:i]
}
if json[i] == '\\' {
i++
for ; i < len(json); i++ {
if json[i] > '\\' {
continue
}
if json[i] == '"' {
// look for an escaped slash
if json[i-1] == '\\' {
n := 0
for j := i - 2; j > 0; j-- {
if json[j] != '\\' {
break
}
n++
}
if n%2 == 0 {
continue
}
}
break
}
}
var ret string
if i+1 < len(json) {
ret = json[:i+1]
} else {
ret = json[:i]
}
return ret, unescape(json[1:i])
}
}
return json, json[1:]
}
// Exists returns true if value exists.
//
// if gjson.Get(json, "name.last").Exists(){
// println("value exists")
// }
func (t Result) Exists() bool {
return t.Type != Null || len(t.Raw) != 0
}
// Value returns one of these types:
//
// bool, for JSON booleans
// float64, for JSON numbers
// Number, for JSON numbers
// string, for JSON string literals
// nil, for JSON null
//
func (t Result) Value() interface{} {
if t.Type == String {
return t.Str
}
switch t.Type {
default:
return nil
case False:
return false
case Number:
return t.Num
case JSON:
r := t.arrayOrMap(0, true)
if r.vc == '{' {
return r.oi
} else if r.vc == '[' {
return r.ai
}
return nil
case True:
return true
}
}
func parseString(json string, i int) (int, string, bool, bool) {
var s = i
for ; i < len(json); i++ {
if json[i] > '\\' {
continue
}
if json[i] == '"' {
return i + 1, json[s-1 : i+1], false, true
}
if json[i] == '\\' {
i++
for ; i < len(json); i++ {
if json[i] > '\\' {
continue
}
if json[i] == '"' {
// look for an escaped slash
if json[i-1] == '\\' {
n := 0
for j := i - 2; j > 0; j-- {
if json[j] != '\\' {
break
}
n++
}
if n%2 == 0 {
continue
}
}
return i + 1, json[s-1 : i+1], true, true
}
}
break
}
}
return i, json[s-1:], false, false
}
func parseNumber(json string, i int) (int, string) {
var s = i
i++
for ; i < len(json); i++ {
if json[i] <= ' ' || json[i] == ',' || json[i] == ']' || json[i] == '}' {
return i, json[s:i]
}
}
return i, json[s:]
}
func parseLiteral(json string, i int) (int, string) {
var s = i
i++
for ; i < len(json); i++ {
if json[i] < 'a' || json[i] > 'z' {
return i, json[s:i]
}
}
return i, json[s:]
}
type arrayPathResult struct {
part string
path string
more bool
alogok bool
arrch bool
alogkey string
query struct {
on bool
path string
op string
value string
all bool
}
}
func parseArrayPath(path string) (r arrayPathResult) {
for i := 0; i < len(path); i++ {
if path[i] == '.' {
r.part = path[:i]
r.path = path[i+1:]
r.more = true
return
}
if path[i] == '#' {
r.arrch = true
if i == 0 && len(path) > 1 {
if path[1] == '.' {
r.alogok = true
r.alogkey = path[2:]
r.path = path[:1]
} else if path[1] == '[' {
r.query.on = true
// query
i += 2
// whitespace
for ; i < len(path); i++ {
if path[i] > ' ' {
break
}
}
s := i
for ; i < len(path); i++ {
if path[i] <= ' ' ||
path[i] == '!' ||
path[i] == '=' ||
path[i] == '<' ||
path[i] == '>' ||
path[i] == '%' ||
path[i] == ']' {
break
}
}
r.query.path = path[s:i]
// whitespace
for ; i < len(path); i++ {
if path[i] > ' ' {
break
}
}
if i < len(path) {
s = i
if path[i] == '!' {
if i < len(path)-1 && path[i+1] == '=' {
i++
}
} else if path[i] == '<' || path[i] == '>' {
if i < len(path)-1 && path[i+1] == '=' {
i++
}
} else if path[i] == '=' {
if i < len(path)-1 && path[i+1] == '=' {
s++
i++
}
}
i++
r.query.op = path[s:i]
// whitespace
for ; i < len(path); i++ {
if path[i] > ' ' {
break
}
}
s = i
for ; i < len(path); i++ {
if path[i] == '"' {
i++
s2 := i
for ; i < len(path); i++ {
if path[i] > '\\' {
continue
}
if path[i] == '"' {
// look for an escaped slash
if path[i-1] == '\\' {
n := 0
for j := i - 2; j > s2-1; j-- {
if path[j] != '\\' {
break
}
n++
}
if n%2 == 0 {
continue
}
}
break
}
}
} else if path[i] == ']' {
if i+1 < len(path) && path[i+1] == '#' {
r.query.all = true
}
break
}
}
if i > len(path) {
i = len(path)
}
v := path[s:i]
for len(v) > 0 && v[len(v)-1] <= ' ' {
v = v[:len(v)-1]
}
r.query.value = v
}
}
}
continue
}
}
r.part = path
r.path = ""
return
}
type objectPathResult struct {
part string
path string
wild bool
more bool
}
func parseObjectPath(path string) (r objectPathResult) {
for i := 0; i < len(path); i++ {
if path[i] == '.' {
r.part = path[:i]
r.path = path[i+1:]
r.more = true
return
}
if path[i] == '*' || path[i] == '?' {
r.wild = true
continue
}
if path[i] == '\\' {
// go into escape mode. this is a slower path that
// strips off the escape character from the part.
epart := []byte(path[:i])
i++
if i < len(path) {
epart = append(epart, path[i])
i++
for ; i < len(path); i++ {
if path[i] == '\\' {
i++
if i < len(path) {
epart = append(epart, path[i])
}
continue
} else if path[i] == '.' {
r.part = string(epart)
r.path = path[i+1:]
r.more = true
return
} else if path[i] == '*' || path[i] == '?' {
r.wild = true
}
epart = append(epart, path[i])
}
}
// append the last part
r.part = string(epart)
return
}
}
r.part = path
return
}
func parseSquash(json string, i int) (int, string) {
// expects that the lead character is a '[' or '{'
// squash the value, ignoring all nested arrays and objects.
// the first '[' or '{' has already been read
s := i
i++
depth := 1
for ; i < len(json); i++ {
if json[i] >= '"' && json[i] <= '}' {
switch json[i] {
case '"':
i++
s2 := i
for ; i < len(json); i++ {
if json[i] > '\\' {
continue
}
if json[i] == '"' {
// look for an escaped slash
if json[i-1] == '\\' {
n := 0
for j := i - 2; j > s2-1; j-- {
if json[j] != '\\' {
break
}
n++
}
if n%2 == 0 {
continue
}
}
break
}
}
case '{', '[':
depth++
case '}', ']':
depth--
if depth == 0 {
i++
return i, json[s:i]
}
}
}
}
return i, json[s:]
}
func parseObject(c *parseContext, i int, path string) (int, bool) {
var pmatch, kesc, vesc, ok, hit bool
var key, val string
rp := parseObjectPath(path)
for i < len(c.json) {
for ; i < len(c.json); i++ {
if c.json[i] == '"' {
// parse_key_string
// this is slightly different from getting s string value
// because we don't need the outer quotes.
i++
var s = i
for ; i < len(c.json); i++ {
if c.json[i] > '\\' {
continue
}
if c.json[i] == '"' {
i, key, kesc, ok = i+1, c.json[s:i], false, true
goto parse_key_string_done
}
if c.json[i] == '\\' {
i++
for ; i < len(c.json); i++ {
if c.json[i] > '\\' {
continue
}
if c.json[i] == '"' {
// look for an escaped slash
if c.json[i-1] == '\\' {
n := 0
for j := i - 2; j > 0; j-- {
if c.json[j] != '\\' {
break
}
n++
}
if n%2 == 0 {
continue
}
}
i, key, kesc, ok = i+1, c.json[s:i], true, true
goto parse_key_string_done
}
}
break
}
}
i, key, kesc, ok = i, c.json[s:], false, false
parse_key_string_done:
break
}
if c.json[i] == '}' {
return i + 1, false
}
}
if !ok {
return i, false
}
if rp.wild {
if kesc {
pmatch = match.Match(unescape(key), rp.part)
} else {
pmatch = match.Match(key, rp.part)
}
} else {
if kesc {
pmatch = rp.part == unescape(key)
} else {
pmatch = rp.part == key
}
}
hit = pmatch && !rp.more
for ; i < len(c.json); i++ {
switch c.json[i] {
default:
continue
case '"':
i++
i, val, vesc, ok = parseString(c.json, i)
if !ok {
return i, false
}
if hit {
if vesc {
c.value.Str = unescape(val[1 : len(val)-1])
} else {
c.value.Str = val[1 : len(val)-1]
}
c.value.Raw = val
c.value.Type = String
return i, true
}
case '{':
if pmatch && !hit {
i, hit = parseObject(c, i+1, rp.path)
if hit {
return i, true
}
} else {
i, val = parseSquash(c.json, i)
if hit {
c.value.Raw = val
c.value.Type = JSON
return i, true
}
}
case '[':
if pmatch && !hit {
i, hit = parseArray(c, i+1, rp.path)
if hit {
return i, true
}
} else {
i, val = parseSquash(c.json, i)
if hit {
c.value.Raw = val
c.value.Type = JSON
return i, true
}
}
case '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
i, val = parseNumber(c.json, i)
if hit {
c.value.Raw = val
c.value.Type = Number
c.value.Num, _ = strconv.ParseFloat(val, 64)
return i, true
}
case 't', 'f', 'n':
vc := c.json[i]
i, val = parseLiteral(c.json, i)
if hit {
c.value.Raw = val
switch vc {
case 't':
c.value.Type = True
case 'f':
c.value.Type = False
}
return i, true
}
}
break
}
}
return i, false
}
func queryMatches(rp *arrayPathResult, value Result) bool {
rpv := rp.query.value
if len(rpv) > 2 && rpv[0] == '"' && rpv[len(rpv)-1] == '"' {
rpv = rpv[1 : len(rpv)-1]
}
switch value.Type {
case String:
switch rp.query.op {
case "=":
return value.Str == rpv
case "!=":
return value.Str != rpv
case "<":
return value.Str < rpv
case "<=":
return value.Str <= rpv
case ">":
return value.Str > rpv
case ">=":
return value.Str >= rpv
case "%":
return match.Match(value.Str, rpv)
}
case Number:
rpvn, _ := strconv.ParseFloat(rpv, 64)
switch rp.query.op {
case "=":
return value.Num == rpvn
case "!=":
return value.Num == rpvn
case "<":
return value.Num < rpvn
case "<=":
return value.Num <= rpvn
case ">":
return value.Num > rpvn
case ">=":
return value.Num >= rpvn
}
case True:
switch rp.query.op {
case "=":
return rpv == "true"
case "!=":
return rpv != "true"
case ">":
return rpv == "false"
case ">=":
return true
}
case False:
switch rp.query.op {
case "=":
return rpv == "false"
case "!=":
return rpv != "false"
case "<":
return rpv == "true"
case "<=":
return true
}
}
return false
}
func parseArray(c *parseContext, i int, path string) (int, bool) {
var pmatch, vesc, ok, hit bool
var val string
var h int
var alog []int
var partidx int
var multires []byte
rp := parseArrayPath(path)
if !rp.arrch {
n, err := strconv.ParseUint(rp.part, 10, 64)
if err != nil {
partidx = -1
} else {
partidx = int(n)
}
}
for i < len(c.json) {
if !rp.arrch {
pmatch = partidx == h
hit = pmatch && !rp.more
}
h++
if rp.alogok {
alog = append(alog, i)
}
for ; i < len(c.json); i++ {
switch c.json[i] {
default:
continue
case '"':
i++
i, val, vesc, ok = parseString(c.json, i)
if !ok {
return i, false
}
if hit {
if rp.alogok {
break
}
if vesc {
c.value.Str = unescape(val[1 : len(val)-1])
} else {
c.value.Str = val[1 : len(val)-1]
}
c.value.Raw = val
c.value.Type = String
return i, true
}
case '{':
if pmatch && !hit {
i, hit = parseObject(c, i+1, rp.path)
if hit {
if rp.alogok {
break
}
return i, true
}
} else {
i, val = parseSquash(c.json, i)
if rp.query.on {
res := Get(val, rp.query.path)
if queryMatches(&rp, res) {
if rp.more {
res = Get(val, rp.path)
} else {
res = Result{Raw: val, Type: JSON}
}
if rp.query.all {
if len(multires) == 0 {
multires = append(multires, '[')
} else {
multires = append(multires, ',')
}
multires = append(multires, res.Raw...)
} else {
c.value = res
return i, true
}
}
} else if hit {
if rp.alogok {
break
}
c.value.Raw = val
c.value.Type = JSON
return i, true
}
}
case '[':
if pmatch && !hit {
i, hit = parseArray(c, i+1, rp.path)
if hit {
if rp.alogok {
break
}
return i, true
}
} else {
i, val = parseSquash(c.json, i)
if hit {
if rp.alogok {
break
}
c.value.Raw = val
c.value.Type = JSON
return i, true
}
}
case '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
i, val = parseNumber(c.json, i)
if hit {
if rp.alogok {
break
}
c.value.Raw = val
c.value.Type = Number
c.value.Num, _ = strconv.ParseFloat(val, 64)
return i, true
}
case 't', 'f', 'n':
vc := c.json[i]
i, val = parseLiteral(c.json, i)
if hit {
if rp.alogok {
break
}
c.value.Raw = val
switch vc {
case 't':
c.value.Type = True
case 'f':
c.value.Type = False
}
return i, true
}
case ']':
if rp.arrch && rp.part == "#" {
if rp.alogok {
var jsons = make([]byte, 0, 64)
jsons = append(jsons, '[')
for j, k := 0, 0; j < len(alog); j++ {
res := Get(c.json[alog[j]:], rp.alogkey)
if res.Exists() {
if k > 0 {
jsons = append(jsons, ',')
}
jsons = append(jsons, []byte(res.Raw)...)
k++
}
}
jsons = append(jsons, ']')
c.value.Type = JSON
c.value.Raw = string(jsons)
return i + 1, true
} else {
if rp.alogok {
break
}
c.value.Raw = val
c.value.Type = Number
c.value.Num = float64(h - 1)
c.calcd = true
return i + 1, true
}
}
if len(multires) > 0 && !c.value.Exists() {
c.value = Result{
Raw: string(append(multires, ']')),
Type: JSON,
}
}
return i + 1, false
}
break
}
}
return i, false
}
type parseContext struct {
json string
value Result
calcd bool
}
// Get searches json for the specified path.
// A path is in dot syntax, such as "name.last" or "age".
// This function expects that the json is well-formed, and does not validate.
// Invalid json will not panic, but it may return back unexpected results.
// When the value is found it's returned immediately.
//
// A path is a series of keys searated by a dot.
// A key may contain special wildcard characters '*' and '?'.
// To access an array value use the index as the key.
// To get the number of elements in an array or to access a child path, use the '#' character.
// The dot and wildcard character can be escaped with '\'.
//
// {
// "name": {"first": "Tom", "last": "Anderson"},
// "age":37,
// "children": ["Sara","Alex","Jack"],
// "friends": [
// {"first": "James", "last": "Murphy"},
// {"first": "Roger", "last": "Craig"}
// ]
// }
// "name.last" >> "Anderson"
// "age" >> 37
// "children" >> ["Sara","Alex","Jack"]
// "children.#" >> 3
// "children.1" >> "Alex"
// "child*.2" >> "Jack"
// "c?ildren.0" >> "Sara"
// "friends.#.first" >> ["James","Roger"]
//
func Get(json, path string) Result {
var i int
var c = &parseContext{json: json}
for ; i < len(c.json); i++ {
if c.json[i] == '{' {
i++
parseObject(c, i, path)
break
}
if c.json[i] == '[' {
i++
parseArray(c, i, path)
break
}
}
if len(c.value.Raw) > 0 && !c.calcd {
jhdr := *(*reflect.StringHeader)(unsafe.Pointer(&json))
rhdr := *(*reflect.StringHeader)(unsafe.Pointer(&(c.value.Raw)))
c.value.Index = int(rhdr.Data - jhdr.Data)
if c.value.Index < 0 || c.value.Index >= len(json) {
c.value.Index = 0
}
}
return c.value
}
func fromBytesGet(result Result) Result {
// safely get the string headers
rawhi := *(*reflect.StringHeader)(unsafe.Pointer(&result.Raw))
strhi := *(*reflect.StringHeader)(unsafe.Pointer(&result.Str))
// create byte slice headers
rawh := reflect.SliceHeader{Data: rawhi.Data, Len: rawhi.Len}
strh := reflect.SliceHeader{Data: strhi.Data, Len: strhi.Len}
if strh.Data == 0 {
// str is nil
if rawh.Data == 0 {
// raw is nil
result.Raw = ""
} else {
// raw has data, safely copy the slice header to a string
result.Raw = string(*(*[]byte)(unsafe.Pointer(&rawh)))
}
result.Str = ""
} else if rawh.Data == 0 {
// raw is nil
result.Raw = ""
// str has data, safely copy the slice header to a string
result.Str = string(*(*[]byte)(unsafe.Pointer(&strh)))
} else if strh.Data >= rawh.Data &&
int(strh.Data)+strh.Len <= int(rawh.Data)+rawh.Len {
// Str is a substring of Raw.
start := int(strh.Data - rawh.Data)
// safely copy the raw slice header
result.Raw = string(*(*[]byte)(unsafe.Pointer(&rawh)))
// substring the raw
result.Str = result.Raw[start : start+strh.Len]
} else {
// safely copy both the raw and str slice headers to strings
result.Raw = string(*(*[]byte)(unsafe.Pointer(&rawh)))
result.Str = string(*(*[]byte)(unsafe.Pointer(&strh)))
}
return result
}
// GetBytes searches json for the specified path.
// If working with bytes, this method preferred over Get(string(data), path)
func GetBytes(json []byte, path string) Result {
var result Result
if json != nil {
// unsafe cast to string
result = Get(*(*string)(unsafe.Pointer(&json)), path)
result = fromBytesGet(result)
}
return result
}
// runeit returns the rune from the the \uXXXX
func runeit(json string) rune {
n, _ := strconv.ParseUint(json[:4], 16, 64)
return rune(n)
}
// unescape unescapes a string
func unescape(json string) string { //, error) {
var str = make([]byte, 0, len(json))
for i := 0; i < len(json); i++ {
switch {
default:
str = append(str, json[i])
case json[i] < ' ':
return string(str)
case json[i] == '\\':
i++
if i >= len(json) {
return string(str)
}
switch json[i] {
default:
return string(str)
case '\\':
str = append(str, '\\')
case '/':
str = append(str, '/')
case 'b':
str = append(str, '\b')
case 'f':
str = append(str, '\f')
case 'n':
str = append(str, '\n')
case 'r':
str = append(str, '\r')
case 't':
str = append(str, '\t')
case '"':
str = append(str, '"')
case 'u':
if i+5 > len(json) {
return string(str)
}
r := runeit(json[i+1:])
i += 5
if utf16.IsSurrogate(r) {
// need another code
if len(json) >= 6 && json[i] == '\\' && json[i+1] == 'u' {
// we expect it to be correct so just consume it
r = utf16.DecodeRune(r, runeit(json[i+2:]))
i += 6
}
}
// provide enough space to encode the largest utf8 possible
str = append(str, 0, 0, 0, 0, 0, 0, 0, 0)
n := utf8.EncodeRune(str[len(str)-8:], r)
str = str[:len(str)-8+n]
i-- // backtrack index by one
}
}
}
return string(str)
}
// Less return true if a token is less than another token.
// The caseSensitive paramater is used when the tokens are Strings.
// The order when comparing two different type is:
//
// Null < False < Number < String < True < JSON
//
func (t Result) Less(token Result, caseSensitive bool) bool {
if t.Type < token.Type {
return true
}
if t.Type > token.Type {
return false
}
if t.Type == String {
if caseSensitive {
return t.Str < token.Str
}
return stringLessInsensitive(t.Str, token.Str)
}
if t.Type == Number {
return t.Num < token.Num
}
return t.Raw < token.Raw
}
func stringLessInsensitive(a, b string) bool {
for i := 0; i < len(a) && i < len(b); i++ {
if a[i] >= 'A' && a[i] <= 'Z' {
if b[i] >= 'A' && b[i] <= 'Z' {
// both are uppercase, do nothing
if a[i] < b[i] {
return true
} else if a[i] > b[i] {
return false
}
} else {
// a is uppercase, convert a to lowercase
if a[i]+32 < b[i] {
return true
} else if a[i]+32 > b[i] {
return false
}
}
} else if b[i] >= 'A' && b[i] <= 'Z' {
// b is uppercase, convert b to lowercase
if a[i] < b[i]+32 {
return true
} else if a[i] > b[i]+32 {
return false
}
} else {
// neither are uppercase
if a[i] < b[i] {
return true
} else if a[i] > b[i] {
return false
}
}
}
return len(a) < len(b)
}
// parseAny parses the next value from a json string.
// A Result is returned when the hit param is set.
// The return values are (i int, res Result, ok bool)
func parseAny(json string, i int, hit bool) (int, Result, bool) {
var res Result
var val string
for ; i < len(json); i++ {
if json[i] == '{' || json[i] == '[' {
i, val = parseSquash(json, i)
if hit {
res.Raw = val
res.Type = JSON
}
return i, res, true
}
if json[i] <= ' ' {
continue
}
switch json[i] {
case '"':
i++
var vesc bool
var ok bool
i, val, vesc, ok = parseString(json, i)
if !ok {
return i, res, false
}
if hit {
res.Type = String
res.Raw = val
if vesc {
res.Str = unescape(val[1 : len(val)-1])
} else {
res.Str = val[1 : len(val)-1]
}
}
return i, res, true
case '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
i, val = parseNumber(json, i)
if hit {
res.Raw = val
res.Type = Number
res.Num, _ = strconv.ParseFloat(val, 64)
}
return i, res, true
case 't', 'f', 'n':
vc := json[i]
i, val = parseLiteral(json, i)
if hit {
res.Raw = val
switch vc {
case 't':
res.Type = True
case 'f':
res.Type = False
}
return i, res, true
}
}
}
return i, res, false
}
var ( // used for testing
testWatchForFallback bool
testLastWasFallback bool
)
// areSimplePaths returns true if all the paths are simple enough
// to parse quickly for GetMany(). Allows alpha-numeric, dots,
// underscores, and the dollar sign. It does not allow non-alnum,
// escape characters, or keys which start with a numbers.
// For example:
// "name.last" == OK
// "user.id0" == OK
// "user.ID" == OK
// "user.first_name" == OK
// "user.firstName" == OK
// "user.0item" == BAD
// "user.#id" == BAD
// "user\.name" == BAD
func areSimplePaths(paths []string) bool {
for _, path := range paths {
var fi int // first key index, for keys with numeric prefix
for i := 0; i < len(path); i++ {
if path[i] >= 'a' && path[i] <= 'z' {
// a-z is likely to be the highest frequency charater.
continue
}
if path[i] == '.' {
fi = i + 1
continue
}
if path[i] >= 'A' && path[i] <= 'Z' {
continue
}
if path[i] == '_' || path[i] == '$' {
continue
}
if i > fi && path[i] >= '0' && path[i] <= '9' {
continue
}
return false
}
}
return true
}
// GetMany searches json for the multiple paths.
// The return value is a Result array where the number of items
// will be equal to the number of input paths.
func GetMany(json string, paths ...string) []Result {
if len(paths) < 4 {
if testWatchForFallback {
testLastWasFallback = false
}
switch len(paths) {
case 0:
// return nil when no paths are specified.
return nil
case 1:
return []Result{Get(json, paths[0])}
case 2:
return []Result{Get(json, paths[0]), Get(json, paths[1])}
case 3:
return []Result{Get(json, paths[0]), Get(json, paths[1]), Get(json, paths[2])}
}
}
var results []Result
var ok bool
var i int
if len(paths) > 512 {
// we can only support up to 512 paths. Is that too many?
goto fallback
}
if !areSimplePaths(paths) {
// If there is even one path that is not considered "simple" then
// we need to use the fallback method.
goto fallback
}
// locate the object token.
for ; i < len(json); i++ {
if json[i] == '{' {
i++
break
}
if json[i] <= ' ' {
continue
}
goto fallback
}
// use the call function table.
if len(paths) <= 8 {
results, ok = getMany8(json, i, paths)
} else if len(paths) <= 16 {
results, ok = getMany16(json, i, paths)
} else if len(paths) <= 32 {
results, ok = getMany32(json, i, paths)
} else if len(paths) <= 64 {
results, ok = getMany64(json, i, paths)
} else if len(paths) <= 128 {
results, ok = getMany128(json, i, paths)
} else if len(paths) <= 256 {
results, ok = getMany256(json, i, paths)
} else if len(paths) <= 512 {
results, ok = getMany512(json, i, paths)
}
if !ok {
// there was some fault while parsing. we should try the
// fallback method. This could result in performance
// degregation in some cases.
goto fallback
}
if testWatchForFallback {
testLastWasFallback = false
}
return results
fallback:
results = results[:0]
for i := 0; i < len(paths); i++ {
results = append(results, Get(json, paths[i]))
}
if testWatchForFallback {
testLastWasFallback = true
}
return results
}
// GetManyBytes searches json for the specified path.
// If working with bytes, this method preferred over
// GetMany(string(data), paths...)
func GetManyBytes(json []byte, paths ...string) []Result {
if json == nil {
return GetMany("", paths...)
}
results := GetMany(*(*string)(unsafe.Pointer(&json)), paths...)
for i := range results {
results[i] = fromBytesGet(results[i])
}
return results
}
// parseGetMany parses a json object for keys that match against the callers
// paths. It's a best-effort attempt and quickly locating and assigning the
// values to the []Result array. If there are failures such as bad json, or
// invalid input paths, or too much recursion, the function will exit with a
// return value of 'false'.
func parseGetMany(
json string, i int,
level uint, kplen int,
paths []string, completed []bool, matches []uint64, results []Result,
) (int, bool) {
if level > 62 {
// The recursion level is limited because the matches []uint64
// array cannot handle more the 64-bits.
return i, false
}
// At this point the last character read was a '{'.
// Read all object keys and try to match against the paths.
var key string
var val string
var vesc, ok bool
next_key:
for ; i < len(json); i++ {
if json[i] == '"' {
// read the key
i, val, vesc, ok = parseString(json, i+1)
if !ok {
return i, false
}
if vesc {
// the value is escaped
key = unescape(val[1 : len(val)-1])
} else {
// just a plain old ascii key
key = val[1 : len(val)-1]
}
var hasMatch bool
var parsedVal bool
var valOrgIndex int
var valPathIndex int
for j := 0; j < len(key); j++ {
if key[j] == '.' {
// we need to look for keys with dot and ignore them.
if i, _, ok = parseAny(json, i, false); !ok {
return i, false
}
continue next_key
}
}
var usedPaths int
// loop through paths and look for matches
for j := 0; j < len(paths); j++ {
if completed[j] {
usedPaths++
// ignore completed paths
continue
}
if level > 0 && (matches[j]>>(level-1))&1 == 0 {
// ignore unmatched paths
usedPaths++
continue
}
// try to match the key to the path
// this is spaghetti code but the idea is to minimize
// calls and variable assignments when comparing the
// key to paths
if len(paths[j])-kplen >= len(key) {
i, k := kplen, 0
for ; k < len(key); k, i = k+1, i+1 {
if key[k] != paths[j][i] {
// no match
goto nomatch
}
}
if i < len(paths[j]) {
if paths[j][i] == '.' {
// matched, but there are still more keys in path
goto match_not_atend
}
}
if len(paths[j]) <= len(key) || kplen != 0 {
// matched and at the end of the path
goto match_atend
}
}
// no match, jump to the nomatch label
goto nomatch
match_atend:
// found a match
// at the end of the path. we must take the value.
usedPaths++
if !parsedVal {
// the value has not been parsed yet. let's do so.
valOrgIndex = i // keep track of the current position.
i, results[j], ok = parseAny(json, i, true)
if !ok {
return i, false
}
parsedVal = true
valPathIndex = j
} else {
results[j] = results[valPathIndex]
}
// mark as complete
completed[j] = true
// jump over the match_not_atend label
goto nomatch
match_not_atend:
// found a match
// still in the middle of the path.
usedPaths++
// mark the path as matched
matches[j] |= 1 << level
if !hasMatch {
hasMatch = true
}
nomatch: // noop label
}
if !parsedVal {
if hasMatch {
// we found a match and the value has not been parsed yet.
// let's find out if the next value type is an object.
for ; i < len(json); i++ {
if json[i] <= ' ' || json[i] == ':' {
continue
}
break
}
if i < len(json) {
if json[i] == '{' {
// it's an object. let's go deeper
i, ok = parseGetMany(json, i+1, level+1, kplen+len(key)+1, paths, completed, matches, results)
if !ok {
return i, false
}
} else {
// not an object. just parse and ignore.
if i, _, ok = parseAny(json, i, false); !ok {
return i, false
}
}
}
} else {
// Since there was no matches we can just parse the value and
// ignore the result.
if i, _, ok = parseAny(json, i, false); !ok {
return i, false
}
}
} else if hasMatch && len(results[valPathIndex].Raw) > 0 && results[valPathIndex].Raw[0] == '{' {
// The value was already parsed and the value type is an object.
// Rewind the json index and let's parse deeper.
i = valOrgIndex
for ; i < len(json); i++ {
if json[i] == '{' {
break
}
}
i, ok = parseGetMany(json, i+1, level+1, kplen+len(key)+1, paths, completed, matches, results)
if !ok {
return i, false
}
}
if usedPaths == len(paths) {
// all paths have been used, either completed or matched.
// we should stop parsing this object to save CPU cycles.
if level > 0 && i < len(json) {
i, _ = parseSquash(json, i)
}
return i, true
}
} else if json[i] == '}' {
// reached the end of the object. end it here.
return i + 1, true
}
}
return i, true
}
// Call table for GetMany. Using an isolated function allows for allocating
// arrays with know capacities on the stack, as opposed to dynamically
// allocating on the heap. This can provide a tremendous performance boost
// by avoiding the GC.
func getMany8(json string, i int, paths []string) ([]Result, bool) {
const max = 8
var completed = make([]bool, 0, max)
var matches = make([]uint64, 0, max)
var results = make([]Result, 0, max)
completed = completed[0:len(paths):max]
matches = matches[0:len(paths):max]
results = results[0:len(paths):max]
_, ok := parseGetMany(json, i, 0, 0, paths, completed, matches, results)
return results, ok
}
func getMany16(json string, i int, paths []string) ([]Result, bool) {
const max = 16
var completed = make([]bool, 0, max)
var matches = make([]uint64, 0, max)
var results = make([]Result, 0, max)
completed = completed[0:len(paths):max]
matches = matches[0:len(paths):max]
results = results[0:len(paths):max]
_, ok := parseGetMany(json, i, 0, 0, paths, completed, matches, results)
return results, ok
}
func getMany32(json string, i int, paths []string) ([]Result, bool) {
const max = 32
var completed = make([]bool, 0, max)
var matches = make([]uint64, 0, max)
var results = make([]Result, 0, max)
completed = completed[0:len(paths):max]
matches = matches[0:len(paths):max]
results = results[0:len(paths):max]
_, ok := parseGetMany(json, i, 0, 0, paths, completed, matches, results)
return results, ok
}
func getMany64(json string, i int, paths []string) ([]Result, bool) {
const max = 64
var completed = make([]bool, 0, max)
var matches = make([]uint64, 0, max)
var results = make([]Result, 0, max)
completed = completed[0:len(paths):max]
matches = matches[0:len(paths):max]
results = results[0:len(paths):max]
_, ok := parseGetMany(json, i, 0, 0, paths, completed, matches, results)
return results, ok
}
func getMany128(json string, i int, paths []string) ([]Result, bool) {
const max = 128
var completed = make([]bool, 0, max)
var matches = make([]uint64, 0, max)
var results = make([]Result, 0, max)
completed = completed[0:len(paths):max]
matches = matches[0:len(paths):max]
results = results[0:len(paths):max]
_, ok := parseGetMany(json, i, 0, 0, paths, completed, matches, results)
return results, ok
}
func getMany256(json string, i int, paths []string) ([]Result, bool) {
const max = 256
var completed = make([]bool, 0, max)
var matches = make([]uint64, 0, max)
var results = make([]Result, 0, max)
completed = completed[0:len(paths):max]
matches = matches[0:len(paths):max]
results = results[0:len(paths):max]
_, ok := parseGetMany(json, i, 0, 0, paths, completed, matches, results)
return results, ok
}
func getMany512(json string, i int, paths []string) ([]Result, bool) {
const max = 512
var completed = make([]bool, 0, max)
var matches = make([]uint64, 0, max)
var results = make([]Result, 0, max)
completed = completed[0:len(paths):max]
matches = matches[0:len(paths):max]
results = results[0:len(paths):max]
_, ok := parseGetMany(json, i, 0, 0, paths, completed, matches, results)
return results, ok
}