v/vlib/x/json2/encoder.v

524 lines
14 KiB
V

// Copyright (c) 2019-2024 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module json2
import time
// Encoder encodes the an `Any` type into JSON representation.
// It provides parameters in order to change the end result.
pub struct Encoder {
newline u8
newline_spaces_count int
escape_unicode bool = true
}
// byte array versions of the most common tokens/chars to avoid reallocations
const null_in_bytes = 'null'
const true_in_string = 'true'
const false_in_string = 'false'
const zero_rune = `0`
const comma_rune = `,`
const colon_rune = `:`
const unicode_escape_chars = [`\\`, `u`]!
const quote_rune = `"`
const escaped_chars = [(r'\b'), (r'\f'), (r'\n'), (r'\r'), (r'\t')]!
const curly_open_rune = `{`
const curly_close_rune = `}`
// encode is a generic function that encodes a type into a JSON string.
pub fn encode[T](val T) string {
$if T is $array {
return encode_array(val)
} $else {
mut buf := []u8{}
defer {
unsafe { buf.free() }
}
encoder := Encoder{}
encoder.encode_value(val, mut buf) or {
println(err)
encoder.encode_value[string]('null', mut buf) or {}
}
return buf.bytestr()
}
}
// encode_array is a generic function that encodes a array into a JSON string.
fn encode_array[T](val []T) string {
mut buf := []u8{}
defer {
unsafe { buf.free() }
}
encoder := Encoder{}
encoder.encode_array(val, 1, mut buf) or {
println(err)
encoder.encode_value[string]('null', mut buf) or {}
}
return buf.bytestr()
}
// encode_pretty ...
pub fn encode_pretty[T](typed_data T) string {
encoded := encode(typed_data)
raw_decoded := raw_decode(encoded) or { 0 }
return raw_decoded.prettify_json_str()
}
// encode_value encodes a value to the specific buffer.
pub fn (e &Encoder) encode_value[T](val T, mut buf []u8) ! {
e.encode_value_with_level[T](val, 1, mut buf)!
}
fn (e &Encoder) encode_newline(level int, mut buf []u8) ! {
if e.newline != 0 {
buf << e.newline
for j := 0; j < level * e.newline_spaces_count; j++ {
buf << ` `
}
}
}
fn (e &Encoder) encode_map[T](value T, level int, mut buf []u8) ! {
buf << json2.curly_open_rune
mut idx := 0
for k, v in value {
e.encode_newline(level, mut buf)!
// e.encode_string(k.str(), mut buf)!
e.encode_string(k, mut buf)!
buf << json2.colon_rune
if e.newline != 0 {
buf << ` `
}
// workaround to avoid `cannot convert 'struct x__json2__Any' to 'struct string'`
$if v is $sumtype {
$for variant_value in v.variants {
if v is variant_value {
e.encode_value_with_level(v, level + 1, mut buf)!
}
}
} $else {
e.encode_value_with_level(v, level + 1, mut buf)!
}
if idx < value.len - 1 {
buf << json2.comma_rune
}
idx++
}
// e.encode_newline(level, mut buf)!
e.encode_newline(level - 1, mut buf)!
buf << json2.curly_close_rune
}
fn (e &Encoder) encode_value_with_level[T](val T, level int, mut buf []u8) ! {
$if val is $option {
workaround := val
if workaround != none {
e.encode_value_with_level(val, level, mut buf)!
}
} $else $if T is string {
e.encode_string(val, mut buf)!
} $else $if T is $sumtype {
$for v in val.variants {
if val is v {
e.encode_value_with_level(val, level, mut buf)!
}
}
} $else $if T is $alias {
// TODO
} $else $if T is time.Time {
str_value := val.format_rfc3339()
buf << json2.quote_rune
unsafe { buf.push_many(str_value.str, str_value.len) }
buf << json2.quote_rune
} $else $if T is $map {
e.encode_map(val, level, mut buf)!
} $else $if T is $array {
e.encode_array(val, level, mut buf)!
} $else $if T is Encodable {
str_value := val.json_str()
unsafe { buf.push_many(str_value.str, str_value.len) }
} $else $if T is Null {
unsafe { buf.push_many(json2.null_in_bytes.str, json2.null_in_bytes.len) }
} $else $if T is $struct {
e.encode_struct(val, level, mut buf)!
} $else $if T is $enum {
str_int := int(val).str()
unsafe { buf.push_many(str_int.str, str_int.len) }
} $else $if T is $int || T is $float || T is bool {
str_int := val.str()
unsafe { buf.push_many(str_int.str, str_int.len) }
} $else {
return error('cannot encode value with ${typeof(val).name} type')
}
}
fn (e &Encoder) encode_struct[U](val U, level int, mut buf []u8) ! {
buf << json2.curly_open_rune
mut i := 0
mut fields_len := 0
$for field in U.fields {
$if field.is_option {
if val.$(field.name) != none {
fields_len++
}
} $else {
fields_len++
}
}
$for field in U.fields {
mut ignore_field := false
mut skip_field := false
value := val.$(field.name)
is_nil := val.$(field.name).str() == '&nil'
mut json_name := ''
for attr in field.attrs {
if attr.contains('json: ') {
json_name = attr.replace('json: ', '')
if json_name == '-' {
ignore_field = true
skip_field = true
}
break
}
}
if skip_field {
i++
fields_len--
} else {
$if value is $option {
workaround := val.$(field.name)
if workaround != none { // smartcast
e.encode_newline(level, mut buf)!
if json_name != '' {
e.encode_string(json_name, mut buf)!
} else {
e.encode_string(field.name, mut buf)!
}
buf << json2.colon_rune
if e.newline != 0 {
buf << ` `
}
e.encode_value_with_level(value, level, mut buf)!
} else {
ignore_field = true
}
} $else {
is_none := val.$(field.name).str() == 'unknown sum type value' // assert json.encode(StructType[SumTypes]{}) == '{}'
if !is_none && !is_nil {
e.encode_newline(level, mut buf)!
if json_name != '' {
e.encode_string(json_name, mut buf)!
} else {
e.encode_string(field.name, mut buf)!
}
buf << json2.colon_rune
if e.newline != 0 {
buf << ` `
}
}
$if field.indirections != 0 {
if val.$(field.name) != unsafe { nil } {
$if field.indirections == 1 {
e.encode_value_with_level(*val.$(field.name), level + 1, mut
buf)!
}
$if field.indirections == 2 {
e.encode_value_with_level(**val.$(field.name), level + 1, mut
buf)!
}
$if field.indirections == 3 {
e.encode_value_with_level(***val.$(field.name), level + 1, mut
buf)!
}
}
} $else $if field.typ is string {
e.encode_string(val.$(field.name).str(), mut buf)!
} $else $if field.typ is time.Time {
str_value := val.$(field.name).format_rfc3339()
buf << json2.quote_rune
unsafe { buf.push_many(str_value.str, str_value.len) }
buf << json2.quote_rune
} $else $if field.typ is bool {
if value {
unsafe { buf.push_many(json2.true_in_string.str, json2.true_in_string.len) }
} else {
unsafe { buf.push_many(json2.false_in_string.str, json2.false_in_string.len) }
}
} $else $if field.typ in [$float, $int] {
str_value := val.$(field.name).str()
unsafe { buf.push_many(str_value.str, str_value.len) }
} $else $if field.is_array {
// TODO - replace for `field.typ is $array`
e.encode_array(value, level + 1, mut buf)!
} $else $if field.typ is $array {
// e.encode_array(value, level + 1, mut buf)! // FIXME - error: could not infer generic type `U` in call to `encode_array`
} $else $if field.typ is $struct {
e.encode_struct(value, level + 1, mut buf)!
} $else $if field.is_map {
e.encode_map(value, level + 1, mut buf)!
} $else $if field.is_enum {
// TODO - replace for `field.typ is $enum`
// str_value := int(val.$(field.name)).str()
// unsafe { buf.push_many(str_value.str, str_value.len) }
e.encode_value_with_level(val.$(field.name), level + 1, mut buf)!
} $else $if field.typ is $enum {
} $else $if field.typ is $sumtype {
field_value := val.$(field.name)
if field_value.str() != 'unknown sum type value' {
$for v in field_value.variants {
if field_value is v {
e.encode_value_with_level(field_value, level, mut buf)!
}
}
}
} $else $if field.typ is $alias {
$if field.unaliased_typ is string {
e.encode_string(val.$(field.name).str(), mut buf)!
} $else $if field.unaliased_typ is time.Time {
parsed_time := time.parse(val.$(field.name).str()) or { time.Time{} }
e.encode_string(parsed_time.format_rfc3339(), mut buf)!
} $else $if field.unaliased_typ is bool {
if val.$(field.name).str() == json2.true_in_string {
unsafe { buf.push_many(json2.true_in_string.str, json2.true_in_string.len) }
} else {
unsafe { buf.push_many(json2.false_in_string.str, json2.false_in_string.len) }
}
} $else $if field.unaliased_typ in [$float, $int] {
str_value := val.$(field.name).str()
unsafe { buf.push_many(str_value.str, str_value.len) }
} $else $if field.unaliased_typ is $array {
// TODO
} $else $if field.unaliased_typ is $struct {
e.encode_struct(value, level + 1, mut buf)!
} $else $if field.unaliased_typ is $enum {
// TODO
} $else $if field.unaliased_typ is $sumtype {
// TODO
} $else {
return error('the alias ${typeof(val).name} cannot be encoded')
}
} $else {
return error('type ${typeof(val).name} cannot be array encoded')
}
}
}
if i < fields_len - 1 && !ignore_field {
if !is_nil {
buf << json2.comma_rune
}
}
if !ignore_field {
i++
}
}
e.encode_newline(level - 1, mut buf)!
buf << json2.curly_close_rune
// b.measure('encode_struct')
}
fn (e &Encoder) encode_array[U](val []U, level int, mut buf []u8) ! {
buf << `[`
for i in 0 .. val.len {
e.encode_newline(level, mut buf)!
$if U is string || U is bool || U is $int || U is $float {
e.encode_value_with_level(val[i], level + 1, mut buf)!
} $else $if U is $array {
e.encode_array(val[i], level + 1, mut buf)!
} $else $if U is $struct {
e.encode_struct(val[i], level + 1, mut buf)!
} $else $if U is $sumtype {
e.encode_value_with_level(val[i], level + 1, mut buf)!
} $else $if U is $enum {
// TODO test
e.encode_value_with_level(val[i], level + 1, mut buf)!
} $else {
return error('type ${typeof(val).name} cannot be array encoded')
}
if i < val.len - 1 {
buf << json2.comma_rune
}
}
e.encode_newline(level - 1, mut buf)!
buf << `]`
}
// str returns the JSON string representation of the `map[string]Any` type.
pub fn (f map[string]Any) str() string {
return Any(f).json_str()
}
// str returns the JSON string representation of the `[]Any` type.
pub fn (f []Any) str() string {
return Any(f).json_str()
}
// str returns the string representation of the `Any` type. Use the `json_str` method
// if you want to use the escaped str() version of the `Any` type.
pub fn (f Any) str() string {
if f is string {
return f
} else {
return f.json_str()
}
}
// json_str returns the JSON string representation of the `Any` type.
@[manualfree]
pub fn (f Any) json_str() string {
return encode(f)
}
// prettify_json_str returns the pretty-formatted JSON string representation of the `Any` type.
@[manualfree]
pub fn (f Any) prettify_json_str() string {
mut buf := []u8{}
defer {
unsafe { buf.free() }
}
mut enc := Encoder{
newline: `\n`
newline_spaces_count: 2
}
enc.encode_value(f, mut buf) or {}
return buf.bytestr()
}
// CharLengthIterator is an iterator that generates a char
// length value of every iteration based on the given text.
// (e.g.: "t✔" => [t => 1, ✔ => 2])
struct CharLengthIterator {
text string
mut:
idx int
}
fn (mut iter CharLengthIterator) next() ?int {
if iter.idx >= iter.text.len {
return none
}
defer {
iter.idx++
}
mut len := 1
c := iter.text[iter.idx]
if (c & (1 << 7)) != 0 {
for t := u8(1 << 6); (c & t) != 0; t >>= 1 {
len++
iter.idx++
}
}
return len
}
// TODO - Need refactor. Is so slow. The longer the string, the lower the performance.
// encode_string returns the JSON spec-compliant version of the string.
@[manualfree]
fn (e &Encoder) encode_string(s string, mut buf []u8) ! {
mut char_lens := CharLengthIterator{
text: s
}
mut i := 0
buf << json2.quote_rune
for char_len in char_lens {
chr := s[i]
if (char_len == 1 && chr < 0x20) || chr == `\\` || chr == `"` || chr == `/` {
handle_special_char(e, mut buf, chr)
} else {
if char_len == 1 {
buf << chr
} else {
handle_multi_byte_char(e, mut buf, s[i..i + char_len])
}
}
i += char_len
}
buf << json2.quote_rune
}
fn handle_special_char(e &Encoder, mut buf []u8, chr u8) {
if chr in important_escapable_chars {
for j := 0; j < important_escapable_chars.len; j++ {
if chr == important_escapable_chars[j] {
unsafe { buf.push_many(json2.escaped_chars[j].str, json2.escaped_chars[j].len) }
break
}
}
} else if chr == `"` || chr == `/` || chr == `\\` {
buf << `\\`
buf << chr
} else {
for r in json2.unicode_escape_chars {
buf << r
}
buf << json2.zero_rune // \u0
buf << json2.zero_rune // \u00
hex_code := chr.hex()
unsafe { buf.push_many(hex_code.str, hex_code.len) }
}
}
fn handle_multi_byte_char(e &Encoder, mut buf []u8, slice string) {
hex_code := slice.utf32_code().hex() // slow
if !e.escape_unicode || hex_code.len < 4 {
unsafe { buf.push_many(slice.str, slice.len) }
} else if hex_code.len == 4 {
// Handle unicode endpoint
for r in json2.unicode_escape_chars {
buf << r
}
unsafe { buf.push_many(hex_code.str, hex_code.len) }
} else {
// TODO: still figuring out what
// to do with more than 4 chars
// According to https://www.json.org/json-en.html however, any codepoint is valid inside a string,
// so just passing it along should hopefully also work.
unsafe { buf.push_many(slice.str, slice.len) }
}
unsafe {
slice.free()
hex_code.free()
}
}