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//! Processing of the `xml:space` attribute.
use itertools::Itertools;
pub struct NormalizeDefault {
pub has_element_before: bool,
pub has_element_after: bool,
}
pub enum XmlSpaceNormalize {
Default(NormalizeDefault),
Preserve,
}
/// Implements `xml:space` handling per the SVG spec
///
/// Normalizes a string as it comes out of the XML parser's handler
/// for character data according to the SVG rules in
/// <https://www.w3.org/TR/SVG/text.html#WhiteSpace>
pub fn xml_space_normalize(mode: XmlSpaceNormalize, s: &str) -> String {
match mode {
XmlSpaceNormalize::Default(d) => normalize_default(d, s),
XmlSpaceNormalize::Preserve => normalize_preserve(s),
}
}
// From https://www.w3.org/TR/SVG/text.html#WhiteSpace
//
// When xml:space="default", the SVG user agent will do the following
// using a copy of the original character data content. First, it will
// remove all newline characters. Then it will convert all tab
// characters into space characters. Then, it will strip off all
// leading and trailing space characters. Then, all contiguous space
// characters will be consolidated.
fn normalize_default(elements: NormalizeDefault, mut s: &str) -> String {
if !elements.has_element_before {
s = s.trim_start();
}
if !elements.has_element_after {
s = s.trim_end();
}
s.chars()
.filter(|ch| *ch != '\n')
.map(|ch| match ch {
'\t' => ' ',
c => c,
})
.coalesce(|current, next| match (current, next) {
(' ', ' ') => Ok(' '),
(_, _) => Err((current, next)),
})
.collect::<String>()
}
// From https://www.w3.org/TR/SVG/text.html#WhiteSpace
//
// When xml:space="preserve", the SVG user agent will do the following
// using a copy of the original character data content. It will
// convert all newline and tab characters into space characters. Then,
// it will draw all space characters, including leading, trailing and
// multiple contiguous space characters. Thus, when drawn with
// xml:space="preserve", the string "a b" (three spaces between "a"
// and "b") will produce a larger separation between "a" and "b" than
// "a b" (one space between "a" and "b").
fn normalize_preserve(s: &str) -> String {
s.chars()
.map(|ch| match ch {
'\n' | '\t' => ' ',
c => c,
})
.collect()
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn xml_space_default() {
assert_eq!(
xml_space_normalize(
XmlSpaceNormalize::Default(NormalizeDefault {
has_element_before: false,
has_element_after: false,
}),
"\n WS example\n indented lines\n "
),
"WS example indented lines"
);
assert_eq!(
xml_space_normalize(
XmlSpaceNormalize::Default(NormalizeDefault {
has_element_before: false,
has_element_after: false,
}),
"\n \t \tWS \t\t\texample\n \t indented lines\t\t \n "
),
"WS example indented lines"
);
assert_eq!(
xml_space_normalize(
XmlSpaceNormalize::Default(NormalizeDefault {
has_element_before: false,
has_element_after: false,
}),
"\n \t \tWS \t\t\texample\n \t duplicate letters\t\t \n "
),
"WS example duplicate letters"
);
assert_eq!(
xml_space_normalize(
XmlSpaceNormalize::Default(NormalizeDefault {
has_element_before: false,
has_element_after: false,
}),
"\nWS example\nnon-indented lines\n "
),
"WS examplenon-indented lines"
);
assert_eq!(
xml_space_normalize(
XmlSpaceNormalize::Default(NormalizeDefault {
has_element_before: false,
has_element_after: false,
}),
"\nWS example\tnon-indented lines\n "
),
"WS example non-indented lines"
);
}
#[test]
fn xml_space_default_with_elements() {
assert_eq!(
xml_space_normalize(
XmlSpaceNormalize::Default(NormalizeDefault {
has_element_before: true,
has_element_after: false,
}),
" foo \n\t bar "
),
" foo bar"
);
assert_eq!(
xml_space_normalize(
XmlSpaceNormalize::Default(NormalizeDefault {
has_element_before: false,
has_element_after: true,
}),
" foo \nbar "
),
"foo bar "
);
}
#[test]
fn xml_space_preserve() {
assert_eq!(
xml_space_normalize(
XmlSpaceNormalize::Preserve,
"\n WS example\n indented lines\n "
),
" WS example indented lines "
);
assert_eq!(
xml_space_normalize(
XmlSpaceNormalize::Preserve,
"\n \t \tWS \t\t\texample\n \t indented lines\t\t \n "
),
" WS example indented lines "
);
assert_eq!(
xml_space_normalize(
XmlSpaceNormalize::Preserve,
"\n \t \tWS \t\t\texample\n \t duplicate letters\t\t \n "
),
" WS example duplicate letters "
);
}
}