rust/src/header.rs
2024-03-12 21:36:52 -06:00

102 lines
3 KiB
Rust

//! headers are sets of consecutive keywords and tokens, such as
//! `pub const unsafe fn foo` and `pub(crate) unsafe trait Bar`.
//!
//! This module contains general logic for formatting such headers,
//! where they are always placed on a single line except when there
//! are comments between parts of the header.
use std::borrow::Cow;
use rustc_ast as ast;
use rustc_span::symbol::Ident;
use rustc_span::Span;
use crate::comment::combine_strs_with_missing_comments;
use crate::rewrite::RewriteContext;
use crate::shape::Shape;
use crate::utils::rewrite_ident;
pub(crate) fn format_header(
context: &RewriteContext<'_>,
shape: Shape,
parts: Vec<HeaderPart>,
) -> String {
debug!(?parts, "format_header");
let shape = shape.infinite_width();
// Empty `HeaderPart`s are ignored.
let mut parts = parts.into_iter().filter(|x| !x.snippet.is_empty());
let Some(part) = parts.next() else {
return String::new();
};
let mut result = part.snippet.into_owned();
let mut span = part.span;
for part in parts {
debug!(?result, "before combine");
result = combine_strs_with_missing_comments(
context,
&result,
&part.snippet,
span.between(part.span),
shape,
true,
)
.unwrap_or_else(|| format!("{} {}", &result, part.snippet));
debug!(?result);
span = part.span;
}
result
}
#[derive(Debug)]
pub(crate) struct HeaderPart {
/// snippet of this part without surrounding space
snippet: Cow<'static, str>,
span: Span,
}
impl HeaderPart {
pub(crate) fn new(snippet: impl Into<Cow<'static, str>>, span: Span) -> Self {
Self {
snippet: snippet.into(),
span,
}
}
pub(crate) fn ident(context: &RewriteContext<'_>, ident: Ident) -> Self {
Self {
snippet: rewrite_ident(context, ident).to_owned().into(),
span: ident.span,
}
}
pub(crate) fn visibility(context: &RewriteContext<'_>, vis: &ast::Visibility) -> Self {
let snippet = match vis.kind {
ast::VisibilityKind::Public => Cow::from("pub"),
ast::VisibilityKind::Inherited => Cow::from(""),
ast::VisibilityKind::Restricted { ref path, .. } => {
let ast::Path { ref segments, .. } = **path;
let mut segments_iter =
segments.iter().map(|seg| rewrite_ident(context, seg.ident));
if path.is_global() {
segments_iter
.next()
.expect("Non-global path in pub(restricted)?");
}
let is_keyword = |s: &str| s == "crate" || s == "self" || s == "super";
let path = segments_iter.collect::<Vec<_>>().join("::");
let in_str = if is_keyword(&path) { "" } else { "in " };
Cow::from(format!("pub({}{})", in_str, path))
}
};
HeaderPart {
snippet,
span: vis.span,
}
}
}