//! Zed-specific post-processing of [`merman`]-produced SVGs.//!//! Each submodule is a specific pass that tweaks the SVG event iterator in a particular way.//!//! We always produce and consume [`Event`]s with a short lifetime.//! [`Event<'a>`] is backed internally by a [`Cow<'a, [u8]>`](std::borrow::Cow),//! so we don't have lifetime issues when we need to mutate the text in an//! [`Event`], but also don't force allocating a new [`String`] each time.//!//! Many modules contain internal structs that implement [`Iterator`] to make//! reasoning about lifetimes simpler, but these are private implementation//! details.mod accent_colors;mod element_fixup;mod inject_css;mod strip_foreignobject;pub(crate) mod util;use anyhow::{Context as _, Result};use quick_xml::Reader;use quick_xml::events::Event;use crate::MermaidTheme;pub(super) fn postprocess(svg: &str, theme: &MermaidTheme) -> Result<String> { // merman 0.6 already applies the generic resvg-safe cleanup before this point. // The remaining passes are Zed-specific theme and accent adjustments. let svg_id = extract_svg_id(svg); let mut reader = Reader::from_str(svg); reader.config_mut().check_end_names = false; let events = ReaderIter::new(reader); // merman's resvg-safe pipeline already removes foreignObject elements and // replaces their labels with native <text> fallback groups. This pass keeps // those fallback labels, but drops any that merely duplicate a native // <text> (e.g. user journey renders some labels both ways). let events = strip_foreignobject::process(events, svg); let events = element_fixup::process(events, theme); let events = accent_colors::process(events, theme); let events = inject_css::process(events, theme, &svg_id); let mut writer = quick_xml::Writer::new(Vec::with_capacity(svg.len())); for event in events { writer.write_event(event?)?; } String::from_utf8(writer.into_inner()).context("SVG output is not valid UTF-8")}fn extract_svg_id(svg: &str) -> String { let mut reader = Reader::from_str(svg); reader.config_mut().check_end_names = false; for event in ReaderIter::new(reader) { let Ok(Event::Start(e) | Event::Empty(e)) = event else { continue; }; if e.name().as_ref() == b"svg" { return e .try_get_attribute("id") .ok() .flatten() .and_then(|a| a.unescape_value().ok()) .map(|v| v.into_owned()) .unwrap_or_default(); } } String::new()}struct ReaderIter<'a> { reader: Reader<&'a [u8]>, done: bool,}impl<'a> ReaderIter<'a> { fn new(reader: Reader<&'a [u8]>) -> Self { Self { reader, done: false, } }}impl<'a> Iterator for ReaderIter<'a> { type Item = Result<Event<'a>>; fn next(&mut self) -> Option<Self::Item> { if self.done { return None; } match self.reader.read_event() { Ok(Event::Eof) => { self.done = true; None } Ok(event) => Some(Ok(event)), Err(e) => { self.done = true; Some(Err(e.into())) } } }}
//! Zed-specific post-processing of [`merman`]-produced SVGs.
//!
//! Each submodule is a specific pass that tweaks the SVG event iterator in a particular way.
//!
//! We always produce and consume [`Event`]s with a short lifetime.
//! [`Event<'a>`] is backed internally by a [`Cow<'a, [u8]>`](std::borrow::Cow),
//! so we don't have lifetime issues when we need to mutate the text in an
//! [`Event`], but also don't force allocating a new [`String`] each time.
//!
//! Many modules contain internal structs that implement [`Iterator`] to make
//! reasoning about lifetimes simpler, but these are private implementation
//! details.
mod accent_colors;
mod element_fixup;
mod inject_css;
mod strip_foreignobject;
pub(crate) mod util;
use anyhow::{Context as _, Result};
use quick_xml::Reader;
use quick_xml::events::Event;
use crate::MermaidTheme;
pub(super) fn postprocess(svg: &str, theme: &MermaidTheme) -> Result<String> {
// merman 0.6 already applies the generic resvg-safe cleanup before this point.
// The remaining passes are Zed-specific theme and accent adjustments.
let svg_id = extract_svg_id(svg);
let mut reader = Reader::from_str(svg);
reader.config_mut().check_end_names = false;
let events = ReaderIter::new(reader);
// merman's resvg-safe pipeline already removes foreignObject elements and
// replaces their labels with native <text> fallback groups. This pass keeps
// those fallback labels, but drops any that merely duplicate a native
// <text> (e.g. user journey renders some labels both ways).
let events = strip_foreignobject::process(events, svg);
let events = element_fixup::process(events, theme);
let events = accent_colors::process(events, theme);
let events = inject_css::process(events, theme, &svg_id);
let mut writer = quick_xml::Writer::new(Vec::with_capacity(svg.len()));
for event in events {
writer.write_event(event?)?;
}
String::from_utf8(writer.into_inner()).context("SVG output is not valid UTF-8")
}
fn extract_svg_id(svg: &str) -> String {
let mut reader = Reader::from_str(svg);
reader.config_mut().check_end_names = false;
for event in ReaderIter::new(reader) {
let Ok(Event::Start(e) | Event::Empty(e)) = event else {
continue;
};
if e.name().as_ref() == b"svg" {
return e
.try_get_attribute("id")
.ok()
.flatten()
.and_then(|a| a.unescape_value().ok())
.map(|v| v.into_owned())
.unwrap_or_default();
}
}
String::new()
}
struct ReaderIter<'a> {
reader: Reader<&'a [u8]>,
done: bool,
}
impl<'a> ReaderIter<'a> {
fn new(reader: Reader<&'a [u8]>) -> Self {
Self {
reader,
done: false,
}
}
}
impl<'a> Iterator for ReaderIter<'a> {
type Item = Result<Event<'a>>;
fn next(&mut self) -> Option<Self::Item> {
if self.done {
return None;
}
match self.reader.read_event() {
Ok(Event::Eof) => {
self.done = true;
None
}
Ok(event) => Some(Ok(event)),
Err(e) => {
self.done = true;
Some(Err(e.into()))
}
}
}
}