/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at
https://mozilla.org/MPL/2.0/. */
//! Specified types for SVG Path.
use crate::parser::{Parse, ParserContext};
use crate::values::animated::{lists, Animate, Procedure};
use crate::values::distance::{ComputeSquaredDistance, SquaredDistance};
use crate::values::generics::basic_shape::GenericShapeCommand;
use crate::values::generics::basic_shape::{ArcSize, ArcSweep, ByTo, CoordinatePair};
use crate::values::CSSFloat;
use cssparser::Parser;
use std::fmt::{self, Write};
use std::iter::{Cloned, Peekable};
use std::ops;
use std::slice;
use style_traits::values::SequenceWriter;
use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
/// Whether to allow empty string in the parser.
#[derive(Clone, Debug, Eq, PartialEq)]
#[allow(missing_docs)]
pub enum AllowEmpty {
Yes,
No,
}
/// The SVG path data.
///
///
https://www.w3.org/TR/SVG11/paths.html#PathData
#[derive(
Clone,
Debug,
Deserialize,
MallocSizeOf,
PartialEq,
Serialize,
SpecifiedValueInfo,
ToAnimatedZero,
ToComputedValue,
ToResolvedValue,
ToShmem,
)]
#[repr(C)]
pub struct SVGPathData(
// TODO(emilio): Should probably measure this somehow only from the
// specified values.
#[ignore_malloc_size_of = "Arc"] pub crate::ArcSlice<PathCommand>,
);
impl SVGPathData {
/// Get the array of PathCommand.
#[inline]
pub fn commands(&self) -> &[PathCommand] {
&self.0
}
/// Create a normalized copy of this path by converting each relative
/// command to an absolute command.
pub fn normalize(&self, reduce: bool) -> Self {
let mut state = PathTraversalState {
subpath_start: CoordPair::new(0.0, 0.0),
pos: CoordPair::new(0.0, 0.0),
last_command: PathCommand::Close,
last_control: CoordPair::new(0.0, 0.0),
};
let iter = self.0.iter().map(|seg| seg.normalize(&mut state, reduce));
SVGPathData(crate::ArcSlice::from_iter(iter))
}
/// Parse this SVG path string with the argument that indicates whether we should allow the
/// empty string.
// We cannot use cssparser::Parser to parse a SVG path string because the spec wants to make
// the SVG path string as compact as possible. (i.e. The whitespaces may be dropped.)
// e.g. "M100 200L100 200" is a valid SVG path string. If we use tokenizer, the first ident
// is "M100", instead of "M", and this is not correct. Therefore, we use a Peekable
// str::Char iterator to check each character.
//
// css-shapes-1 says a path data string that does conform but defines an empty path is
// invalid and causes the entire path() to be invalid, so we use allow_empty to decide
// whether we should allow it.
//
https://drafts.csswg.org/css-shapes-1/#typedef-basic-shape
pub fn parse<'i, 't>(
input: &mut Parser<'i, 't>,
allow_empty: AllowEmpty,
) -> Result<Self, ParseError<'i>> {
let location = input.current_source_location();
let path_string = input.expect_string()?.as_ref();
let (path, ok) = Self::parse_bytes(path_string.as_bytes());
if !ok || (allow_empty == AllowEmpty::No && path.0.is_empty()) {
return Err(location.new_custom_error(StyleParseErrorKind::UnspecifiedError))
}
return Ok(path);
}
/// As above, but just parsing the raw byte stream.
///
/// Returns the (potentially empty or partial) path, and whether the parsing was ok or we found
/// an error. The API is a bit weird because some SVG callers require "parse until first error"
/// behavior.
pub fn parse_bytes(input: &[u8]) -> (Self, bool) {
// Parse the svg path string as multiple sub-paths.
let mut ok = true;
let mut path_parser = PathParser::new(input);
while skip_wsp(&mut path_parser.chars) {
if path_parser.parse_subpath().is_err() {
ok = false;
break;
}
}
let path = Self(crate::ArcSlice::from_iter(path_parser.path.into_iter()));
(path, ok)
}
/// Serializes to the path string, potentially including quotes.
pub fn to_css<W>(&self, dest: &mut CssWriter<W>, quote: bool) -> fmt::Result
where
W: fmt::Write,
{
if quote {
dest.write_char('"')?;
}
let mut writer = SequenceWriter::new(dest, " ");
for command in self.commands() {
writer.write_item(|inner| command.to_css_for_svg(inner))?;
}
if quote {
dest.write_char('"')?;
}
Ok(())
}
}
impl ToCss for SVGPathData {
#[inline]
fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
where
W: fmt::Write,
{
self.to_css(dest, /* quote = */ true)
}
}
impl Parse for SVGPathData {
fn parse<'i, 't>(
_context: &ParserContext,
input: &mut Parser<'i, 't>,
) -> Result<Self, ParseError<'i>> {
// Note that the EBNF allows the path data string in the d property to be empty, so we
// don't reject empty SVG path data.
//
https://svgwg.org/svg2-draft/single-page.html#paths-PathDataBNF
SVGPathData::parse(input, AllowEmpty::Yes)
}
}
impl Animate for SVGPathData {
fn animate(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> {
if self.0.len() != other.0.len() {
return Err(());
}
// FIXME(emilio): This allocates three copies of the path, that's not
// great! Specially, once we're normalized once, we don't need to
// re-normalize again.
let left = self.normalize(false);
let right = other.normalize(false);
let items: Vec<_> = lists::by_computed_value::animate(&left.0, &right.0, procedure)?;
Ok(SVGPathData(crate::ArcSlice::from_iter(items.into_iter())))
}
}
impl ComputeSquaredDistance for SVGPathData {
fn compute_squared_distance(&self, other: &Self) -> Result<SquaredDistance, ()> {
if self.0.len() != other.0.len() {
return Err(());
}
let left = self.normalize(false);
let right = other.normalize(false);
lists::by_computed_value::squared_distance(&left.0, &right.0)
}
}
/// The SVG path command.
/// The fields of these commands are self-explanatory, so we skip the documents.
/// Note: the index of the control points, e.g. control1, control2, are mapping to the control
/// points of the Bézier curve in the spec.
///
///
https://www.w3.org/TR/SVG11/paths.html#PathData
pub type PathCommand = GenericShapeCommand<CSSFloat, CSSFloat>;
/// For internal SVGPath normalization.
#[allow(missing_docs)]
struct PathTraversalState {
subpath_start: CoordPair,
pos: CoordPair,
last_command: PathCommand,
last_control: CoordPair,
}
impl PathCommand {
/// Create a normalized copy of this PathCommand. Absolute commands will be copied as-is while
/// for relative commands an equivalent absolute command will be returned.
///
/// See discussion:
https://github.com/w3c/svgwg/issues/321
/// If reduce is true then the path will be restricted to
/// "M", "L", "C", "A" and "Z" commands.
fn normalize(&self, state: &mut PathTraversalState, reduce: bool) -> Self {
use crate::values::generics::basic_shape::GenericShapeCommand::*;
match *self {
Close => {
state.pos = state.subpath_start;
if reduce {
state.last_command = *self;
}
Close
},
Move { by_to, mut point } => {
if !by_to.is_abs() {
point += state.pos;
}
state.pos = point;
state.subpath_start = point;
if reduce {
state.last_command = *self;
}
Move {
by_to: ByTo::To,
point,
}
},
Line { by_to, mut point } => {
if !by_to.is_abs() {
point += state.pos;
}
state.pos = point;
if reduce {
state.last_command = *self;
}
Line {
by_to: ByTo::To,
point,
}
},
HLine { by_to, mut x } => {
if !by_to.is_abs() {
x += state.pos.x;
}
state.pos.x = x;
if reduce {
state.last_command = *self;
PathCommand::Line { by_to: ByTo::To, point: state.pos }
} else {
HLine { by_to: ByTo::To, x }
}
},
VLine { by_to, mut y } => {
if !by_to.is_abs() {
y += state.pos.y;
}
state.pos.y = y;
if reduce {
state.last_command = *self;
PathCommand::Line { by_to: ByTo::To, point: state.pos }
} else {
VLine { by_to: ByTo::To, y }
}
},
CubicCurve {
by_to,
mut point,
mut control1,
mut control2,
} => {
if !by_to.is_abs() {
point += state.pos;
control1 += state.pos;
control2 += state.pos;
}
state.pos = point;
if reduce {
state.last_command = *self;
state.last_control = control2;
}
CubicCurve {
by_to: ByTo::To,
point,
control1,
control2,
}
},
QuadCurve {
by_to,
mut point,
mut control1,
} => {
if !by_to.is_abs() {
point += state.pos;
control1 += state.pos;
}
if reduce {
let c1 = state.pos + 2. * (control1 - state.pos) / 3.;
let control2 = point + 2. * (control1 - point) / 3.;
state.pos = point;
state.last_command = *self;
state.last_control = control1;
CubicCurve {
by_to: ByTo::To,
point,
control1: c1,
control2,
}
} else {
state.pos = point;
QuadCurve {
by_to: ByTo::To,
point,
control1,
}
}
},
SmoothCubic {
by_to,
mut point,
mut control2,
} => {
if !by_to.is_abs() {
point += state.pos;
control2 += state.pos;
}
if reduce {
let control1 = match state.last_command {
PathCommand::CubicCurve { by_to: _, point: _, control1: _, control2: _ } | PathCommand::Smoo
thCubic { by_to: _, point: _, control2: _ } =>
state.pos + state.pos - state.last_control,
_ => state.pos
};
state.pos = point;
state.last_control = control2;
state.last_command = *self;
CubicCurve {
by_to: ByTo::To,
point,
control1,
control2,
}
} else {
state.pos = point;
SmoothCubic {
by_to: ByTo::To,
point,
control2,
}
}
},
SmoothQuad { by_to, mut point } => {
if !by_to.is_abs() {
point += state.pos;
}
if reduce {
let control = match state.last_command {
PathCommand::QuadCurve { by_to: _, point: _, control1: _ } | PathCommand::SmoothQuad { by_to: _, point: _ } =>
state.pos + state.pos - state.last_control,
_ => state.pos
};
let control1 = state.pos + 2. * (control - state.pos) / 3.;
let control2 = point + 2. * (control - point) / 3.;
state.pos = point;
state.last_command = *self;
state.last_control = control;
CubicCurve {
by_to: ByTo::To,
point,
control1,
control2,
}
} else {
state.pos = point;
SmoothQuad {
by_to: ByTo::To,
point,
}
}
},
Arc {
by_to,
mut point,
radii,
arc_sweep,
arc_size,
rotate,
} => {
if !by_to.is_abs() {
point += state.pos;
}
state.pos = point;
if reduce {
state.last_command = *self;
if radii.x == 0. && radii.y == 0. {
CubicCurve {
by_to: ByTo::To,
point: state.pos,
control1: point,
control2: point,
}
} else {
Arc {
by_to: ByTo::To,
point,
radii,
arc_sweep,
arc_size,
rotate,
}
}
} else {
Arc {
by_to: ByTo::To,
point,
radii,
arc_sweep,
arc_size,
rotate,
}
}
},
}
}
/// The serialization of the svg path.
fn to_css_for_svg<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
where
W: fmt::Write,
{
use crate::values::generics::basic_shape::GenericShapeCommand::*;
match *self {
Close => dest.write_char('Z'),
Move { by_to, point } => {
dest.write_char(if by_to.is_abs() { 'M' } else { 'm' })?;
dest.write_char(' ')?;
point.to_css(dest)
},
Line { by_to, point } => {
dest.write_char(if by_to.is_abs() { 'L' } else { 'l' })?;
dest.write_char(' ')?;
point.to_css(dest)
},
CubicCurve {
by_to,
point,
control1,
control2,
} => {
dest.write_char(if by_to.is_abs() { 'C' } else { 'c' })?;
dest.write_char(' ')?;
control1.to_css(dest)?;
dest.write_char(' ')?;
control2.to_css(dest)?;
dest.write_char(' ')?;
point.to_css(dest)
},
QuadCurve {
by_to,
point,
control1,
} => {
dest.write_char(if by_to.is_abs() { 'Q' } else { 'q' })?;
dest.write_char(' ')?;
control1.to_css(dest)?;
dest.write_char(' ')?;
point.to_css(dest)
},
Arc {
by_to,
point,
radii,
arc_sweep,
arc_size,
rotate,
} => {
dest.write_char(if by_to.is_abs() { 'A' } else { 'a' })?;
dest.write_char(' ')?;
radii.to_css(dest)?;
dest.write_char(' ')?;
rotate.to_css(dest)?;
dest.write_char(' ')?;
(arc_size as i32).to_css(dest)?;
dest.write_char(' ')?;
(arc_sweep as i32).to_css(dest)?;
dest.write_char(' ')?;
point.to_css(dest)
},
HLine { by_to, x } => {
dest.write_char(if by_to.is_abs() { 'H' } else { 'h' })?;
dest.write_char(' ')?;
x.to_css(dest)
},
VLine { by_to, y } => {
dest.write_char(if by_to.is_abs() { 'V' } else { 'v' })?;
dest.write_char(' ')?;
y.to_css(dest)
},
SmoothCubic {
by_to,
point,
control2,
} => {
dest.write_char(if by_to.is_abs() { 'S' } else { 's' })?;
dest.write_char(' ')?;
control2.to_css(dest)?;
dest.write_char(' ')?;
point.to_css(dest)
},
SmoothQuad { by_to, point } => {
dest.write_char(if by_to.is_abs() { 'T' } else { 't' })?;
dest.write_char(' ')?;
point.to_css(dest)
},
}
}
}
/// The path coord type.
pub type CoordPair = CoordinatePair<CSSFloat>;
impl ops::Add<CoordPair> for CoordPair {
type Output = CoordPair;
fn add(self, rhs: CoordPair) -> CoordPair {
Self {
x: self.x + rhs.x,
y: self.y + rhs.y,
}
}
}
impl ops::Sub<CoordPair> for CoordPair {
type Output = CoordPair;
fn sub(self, rhs: CoordPair) -> CoordPair {
Self {
x: self.x - rhs.x,
y: self.y - rhs.y,
}
}
}
impl ops::Mul<CSSFloat> for CoordPair {
type Output = CoordPair;
fn mul(self, f: CSSFloat) -> CoordPair {
Self {
x: self.x * f,
y: self.y * f,
}
}
}
impl ops::Mul<CoordPair> for CSSFloat {
type Output = CoordPair;
fn mul(self, rhs: CoordPair) -> CoordPair {
rhs * self
}
}
impl ops::Div<CSSFloat> for CoordPair {
type Output = CoordPair;
fn div(self, f: CSSFloat) -> CoordPair {
Self {
x: self.x / f,
y: self.y / f,
}
}
}
/// SVG Path parser.
struct PathParser<'a> {
chars: Peekable<Cloned<slice::Iter<'a, u8>>>,
path: Vec<PathCommand>,
}
macro_rules! parse_arguments {
(
$parser:ident,
$by_to:ident,
$enum:ident,
[ $para:ident => $func:ident $(, $other_para:ident => $other_func:ident)* ]
) => {
{
loop {
let $para = $func(&mut $parser.chars)?;
$(
skip_comma_wsp(&mut $parser.chars);
let $other_para = $other_func(&mut $parser.chars)?;
)*
$parser.path.push(
PathCommand::$enum { $by_to, $para $(, $other_para)* }
);
// End of string or the next character is a possible new command.
if !skip_wsp(&mut $parser.chars) ||
$parser.chars.peek().map_or(true, |c| c.is_ascii_alphabetic()) {
break;
}
skip_comma_wsp(&mut $parser.chars);
}
Ok(())
}
}
}
impl<'a> PathParser<'a> {
/// Return a PathParser.
#[inline]
fn new(bytes: &'a [u8]) -> Self {
PathParser {
chars: bytes.iter().cloned().peekable(),
path: Vec::new(),
}
}
/// Parse a sub-path.
fn parse_subpath(&mut self) -> Result<(), ()> {
// Handle "moveto" Command first. If there is no "moveto", this is not a valid sub-path
// (i.e. not a valid moveto-drawto-command-group).
self.parse_moveto()?;
// Handle other commands.
loop {
skip_wsp(&mut self.chars);
if self.chars.peek().map_or(true, |&m| m == b'M' || m == b'm') {
break;
}
let command = self.chars.next().unwrap();
let by_to = if command.is_ascii_uppercase() {
ByTo::To
} else {
ByTo::By
};
skip_wsp(&mut self.chars);
match command {
b'Z' | b'z' => self.parse_closepath(),
b'L' | b'l' => self.parse_lineto(by_to),
b'H' | b'h' => self.parse_h_lineto(by_to),
b'V' | b'v' => self.parse_v_lineto(by_to),
b'C' | b'c' => self.parse_curveto(by_to),
b'S' | b's' => self.parse_smooth_curveto(by_to),
b'Q' | b'q' => self.parse_quadratic_bezier_curveto(by_to),
b'T' | b't' => self.parse_smooth_quadratic_bezier_curveto(by_to),
b'A' | b'a' => self.parse_elliptical_arc(by_to),
_ => return Err(()),
}?;
}
Ok(())
}
/// Parse "moveto" command.
fn parse_moveto(&mut self) -> Result<(), ()> {
let command = match self.chars.next() {
Some(c) if c == b'M' || c == b'm' => c,
_ => return Err(()),
};
skip_wsp(&mut self.chars);
let point = parse_coord(&mut self.chars)?;
let by_to = if command == b'M' { ByTo::To } else { ByTo::By };
self.path.push(PathCommand::Move { by_to, point });
// End of string or the next character is a possible new command.
if !skip_wsp(&mut self.chars) || self.chars.peek().map_or(true, |c| c.is_ascii_alphabetic())
{
return Ok(());
}
skip_comma_wsp(&mut self.chars);
// If a moveto is followed by multiple pairs of coordinates, the subsequent
// pairs are treated as implicit lineto commands.
self.parse_lineto(by_to)
}
/// Parse "closepath" command.
fn parse_closepath(&mut self) -> Result<(), ()> {
self.path.push(PathCommand::Close);
Ok(())
}
/// Parse "lineto" command.
fn parse_lineto(&mut self, by_to: ByTo) -> Result<(), ()> {
parse_arguments!(self, by_to, Line, [ point => parse_coord ])
}
/// Parse horizontal "lineto" command.
fn parse_h_lineto(&mut self, by_to: ByTo) -> Result<(), ()> {
parse_arguments!(self, by_to, HLine, [ x => parse_number ])
}
/// Parse vertical "lineto" command.
fn parse_v_lineto(&mut self, by_to: ByTo) -> Result<(), ()> {
parse_arguments!(self, by_to, VLine, [ y => parse_number ])
}
/// Parse cubic Bézier curve command.
fn parse_curveto(&mut self, by_to: ByTo) -> Result<(), ()> {
parse_arguments!(self, by_to, CubicCurve, [
control1 => parse_coord, control2 => parse_coord, point => parse_coord
])
}
/// Parse smooth "curveto" command.
fn parse_smooth_curveto(&mut self, by_to: ByTo) -> Result<(), ()> {
parse_arguments!(self, by_to, SmoothCubic, [
control2 => parse_coord, point => parse_coord
])
}
/// Parse quadratic Bézier curve command.
fn parse_quadratic_bezier_curveto(&mut self, by_to: ByTo) -> Result<(), ()> {
parse_arguments!(self, by_to, QuadCurve, [
control1 => parse_coord, point => parse_coord
])
}
/// Parse smooth quadratic Bézier curveto command.
fn parse_smooth_quadratic_bezier_curveto(&mut self, by_to: ByTo) -> Result<(), ()> {
parse_arguments!(self, by_to, SmoothQuad, [ point => parse_coord ])
}
/// Parse elliptical arc curve command.
fn parse_elliptical_arc(&mut self, by_to: ByTo) -> Result<(), ()> {
// Parse a flag whose value is '0' or '1'; otherwise, return Err(()).
let parse_arc_size = |iter: &mut Peekable<Cloned<slice::Iter<u8>>>| match iter.next() {
Some(c) if c == b'1' => Ok(ArcSize::Large),
Some(c) if c == b'0' => Ok(ArcSize::Small),
_ => Err(()),
};
let parse_arc_sweep = |iter: &mut Peekable<Cloned<slice::Iter<u8>>>| match iter.next() {
Some(c) if c == b'1' => Ok(ArcSweep::Cw),
Some(c) if c == b'0' => Ok(ArcSweep::Ccw),
_ => Err(()),
};
parse_arguments!(self, by_to, Arc, [
radii => parse_coord,
rotate => parse_number,
arc_size => parse_arc_size,
arc_sweep => parse_arc_sweep,
point => parse_coord
])
}
}
/// Parse a pair of numbers into CoordPair.
fn parse_coord(iter: &mut Peekable<Cloned<slice::Iter<u8>>>) -> Result<CoordPair, ()> {
let x = parse_number(iter)?;
skip_comma_wsp(iter);
let y = parse_number(iter)?;
Ok(CoordPair::new(x, y))
}
/// This is a special version which parses the number for SVG Path. e.g. "M 0.6.5" should be parsed
/// as MoveTo with a coordinate of ("0.6", ".5"), instead of treating 0.6.5 as a non-valid floating
/// point number. In other words, the logic here is similar with that of
/// tokenizer::consume_numeric, which also consumes the number as many as possible, but here the
/// input is a Peekable and we only accept an integer of a floating point number.
///
/// The "number" syntax in https://www.w3.org/TR/SVG/paths.html#PathDataBNF
fn parse_number(iter: &mut Peekable<Cloned<slice::Iter<u8>>>) -> Result<CSSFloat, ()> {
// 1. Check optional sign.
let sign = if iter
.peek()
.map_or(false, |&sign| sign == b'+' || sign == b'-')
{
if iter.next().unwrap() == b'-' {
-1.
} else {
1.
}
} else {
1.
};
// 2. Check integer part.
let mut integral_part: f64 = 0.;
let got_dot = if !iter.peek().map_or(false, |&n| n == b'.') {
// If the first digit in integer part is neither a dot nor a digit, this is not a number.
if iter.peek().map_or(true, |n| !n.is_ascii_digit()) {
return Err(());
}
while iter.peek().map_or(false, |n| n.is_ascii_digit()) {
integral_part = integral_part * 10. + (iter.next().unwrap() - b'0') as f64;
}
iter.peek().map_or(false, |&n| n == b'.')
} else {
true
};
// 3. Check fractional part.
let mut fractional_part: f64 = 0.;
if got_dot {
// Consume '.'.
iter.next();
// If the first digit in fractional part is not a digit, this is not a number.
if iter.peek().map_or(true, |n| !n.is_ascii_digit()) {
return Err(());
}
let mut factor = 0.1;
while iter.peek().map_or(false, |n| n.is_ascii_digit()) {
fractional_part += (iter.next().unwrap() - b'0') as f64 * factor;
factor *= 0.1;
}
}
let mut value = sign * (integral_part + fractional_part);
// 4. Check exp part. The segment name of SVG Path doesn't include 'E' or 'e', so it's ok to
// treat the numbers after 'E' or 'e' are in the exponential part.
if iter.peek().map_or(false, |&exp| exp == b'E' || exp == b'e') {
// Consume 'E' or 'e'.
iter.next();
let exp_sign = if iter
.peek()
.map_or(false, |&sign| sign == b'+' || sign == b'-')
{
if iter.next().unwrap() == b'-' {
-1.
} else {
1.
}
} else {
1.
};
let mut exp: f64 = 0.;
while iter.peek().map_or(false, |n| n.is_ascii_digit()) {
exp = exp * 10. + (iter.next().unwrap() - b'0') as f64;
}
value *= f64::powf(10., exp * exp_sign);
}
if value.is_finite() {
Ok(value.min(f32::MAX as f64).max(f32::MIN as f64) as CSSFloat)
} else {
Err(())
}
}
/// Skip all svg whitespaces, and return true if |iter| hasn't finished.
#[inline]
fn skip_wsp(iter: &mut Peekable<Cloned<slice::Iter<u8>>>) -> bool {
// Note: SVG 1.1 defines the whitespaces as \u{9}, \u{20}, \u{A}, \u{D}.
// However, SVG 2 has one extra whitespace: \u{C}.
// Therefore, we follow the newest spec for the definition of whitespace,
// i.e. \u{9}, \u{20}, \u{A}, \u{C}, \u{D}.
while iter.peek().map_or(false, |c| c.is_ascii_whitespace()) {
iter.next();
}
iter.peek().is_some()
}
/// Skip all svg whitespaces and one comma, and return true if |iter| hasn't finished.
#[inline]
fn skip_comma_wsp(iter: &mut Peekable<Cloned<slice::Iter<u8>>>) -> bool {
if !skip_wsp(iter) {
return false;
}
if *iter.peek().unwrap() != b',' {
return true;
}
iter.next();
skip_wsp(iter)
}
