feat(css/parser): comments supporting

crates/swc_css_codegen/src/comments.rs

@@ -0,0 +1,100 @@
+use swc_common::comments::CommentKind;
+
+use super::*;
+
+macro_rules! write_comments {
+ ($e:expr, $prefix_space:expr, $cmts:expr) => {{
+ let cmts = match $cmts {
+ Some(v) => v,
+ None => return Ok(()),
+ };
+
+ for cmt in cmts.iter() {
+ match cmt.kind {
+ CommentKind::Line => {
+ if $prefix_space {
+ $e.wr.write_comment(" ")?;
+ }
+
+ srcmap!($e, cmt, true);
+
+ $e.wr.write_comment("//")?;
+ $e.wr.write_comment(&cmt.text)?;
+
+ srcmap!($e, cmt, false);
+
+ $e.wr.write_newline()?;
+ }
+ CommentKind::Block => {
+ if $prefix_space {
+ $e.wr.write_comment(" ")?;
+ }
+
+ srcmap!($e, cmt, true);
+
+ $e.wr.write_comment("/*")?;
+ $e.wr.write_comment(&cmt.text)?;
+
+ {
+ let hi = cmt.span_hi();
+
+ if !hi.is_dummy() && hi.0 > 2 {
+ $e.wr.add_srcmap(hi - swc_common::BytePos(2))?;
+ }
+ }
+
+ $e.wr.write_comment("*/")?;
+ $e.wr.write_space()?;
+ }
+ }
+ }
+
+ return Ok(());
+ }};
+}
+
+impl<'a, W: CssWriter> CodeGenerator<'a, W> {
+ pub(super) fn emit_trailing_comments_of_pos(
+ &mut self,
+ pos: BytePos,
+ prefix_space: bool,
+ _is_hi: bool,
+ ) -> Result {
+ if pos.is_dummy() {
+ return Ok(());
+ }
+
+ let comments = match self.comments {
+ Some(ref comments) => comments,
+ None => return Ok(()),
+ };
+
+ let cmts = comments.take_trailing(pos);
+
+ write_comments!(self, prefix_space, &cmts)
+ }
+
+ pub(super) fn emit_leading_comments(&mut self, mut pos: BytePos, is_hi: bool) -> Result {
+ if pos.is_dummy() {
+ return Ok(());
+ }
+
+ let comments = match self.comments {
+ Some(ref comments) => comments,
+ None => return Ok(()),
+ };
+
+ if is_hi {
+ pos = pos - BytePos(1)
+ }
+
+ write_comments!(self, false, comments.take_leading(pos))
+ }
+
+ #[inline(always)]
+ pub(super) fn emit_leading_comments_of_span(&mut self, span: Span, is_hi: bool) -> Result {
+ let pos = if is_hi { span.hi } else { span.lo };
+
+ self.emit_leading_comments(pos, is_hi)
+ }
+}

crates/swc_css_codegen/src/ctx.rs

@@ -2,15 +2,14 @@ use std::ops::{Deref, DerefMut};
 
 use crate::{writer::CssWriter, CodeGenerator};
 
-impl<W> CodeGenerator<W>
-where
- W: CssWriter,
-{
+impl<'a, W: CssWriter> CodeGenerator<'a, W> {
  /// Original context is restored when returned guard is dropped.
  #[inline]
- pub(super) fn with_ctx(&mut self, ctx: Ctx) -> WithCtx<W> {
+ pub(super) fn with_ctx(&mut self, ctx: Ctx) -> WithCtx<'a, '_, W> {
  let orig_ctx = self.ctx;
+
  self.ctx = ctx;
+
  WithCtx {
  orig_ctx,
  inner: self,
@@ -21,25 +20,25 @@ where
 #[derive(Debug, Default, Clone, Copy)]
 pub(crate) struct Ctx {}
 
-pub(super) struct WithCtx<'w, I: 'w + CssWriter> {
- inner: &'w mut CodeGenerator<I>,
+pub(super) struct WithCtx<'a, 'w, I: 'w + CssWriter> {
+ inner: &'w mut CodeGenerator<'a, I>,
  orig_ctx: Ctx,
 }
 
-impl<'w, I: CssWriter> Deref for WithCtx<'w, I> {
- type Target = CodeGenerator<I>;
+impl<'a, 'w, I: CssWriter> Deref for WithCtx<'a, 'w, I> {
+ type Target = CodeGenerator<'a, I>;
 
- fn deref(&self) -> &CodeGenerator<I> {
+ fn deref(&self) -> &CodeGenerator<'a, I> {
  self.inner
  }
 }
-impl<'w, I: CssWriter> DerefMut for WithCtx<'w, I> {
- fn deref_mut(&mut self) -> &mut CodeGenerator<I> {
+impl<'a, 'w, I: CssWriter> DerefMut for WithCtx<'a, 'w, I> {
+ fn deref_mut(&mut self) -> &mut CodeGenerator<'a, I> {
  self.inner
  }
 }
 
-impl<'w, I: CssWriter> Drop for WithCtx<'w, I> {
+impl<'a, 'w, I: CssWriter> Drop for WithCtx<'a, 'w, I> {
  fn drop(&mut self) {
  self.inner.ctx = self.orig_ctx;
  }

crates/swc_css_codegen/src/lib.rs

@@ -5,7 +5,7 @@ pub use std::fmt::Result;
 use std::str::from_utf8;
 
 use serde::{Deserialize, Serialize};
-use swc_common::{BytePos, Span, Spanned, DUMMY_SP};
+use swc_common::{comments::Comments, BytePos, Span, Spanned, DUMMY_SP};
 use swc_css_ast::*;
 use swc_css_codegen_macros::emitter;
 use writer::CssWriter;
@@ -15,6 +15,7 @@ use self::{ctx::Ctx, list::ListFormat};
 
 #[macro_use]
 mod macros;
+mod comments;
 mod ctx;
 mod emit;
 mod list;
@@ -27,30 +28,32 @@ pub struct CodegenConfig {
  pub minify: bool,
 }
 
-#[derive(Debug)]
-pub struct CodeGenerator<W>
+pub struct CodeGenerator<'a, W>
 where
  W: CssWriter,
 {
  wr: W,
+ comments: Option<&'a dyn Comments>,
  config: CodegenConfig,
  ctx: Ctx,
 }
 
-impl<W> CodeGenerator<W>
+impl<'a, W> CodeGenerator<'a, W>
 where
  W: CssWriter,
 {
- pub fn new(wr: W, config: CodegenConfig) -> Self {
+ pub fn new(wr: W, comments: Option<&'a dyn Comments>, config: CodegenConfig) -> Self {
  CodeGenerator {
  wr,
  config,
+ comments,
  ctx: Default::default(),
  }
  }
 
  #[emitter]
  fn emit_stylesheet(&mut self, n: &Stylesheet) -> Result {
+ self.emit_leading_comments_of_span(n.span(), false)?;
  self.emit_list(
  &n.rules,
  if self.config.minify {
@@ -59,6 +62,7 @@ where
  ListFormat::NotDelimited | ListFormat::MultiLine
  },
  )?;
+ self.emit_trailing_comments_of_pos(n.span().hi, true, true)?;
  }
 
  #[emitter]

crates/swc_css_codegen/src/macros.rs

@@ -92,3 +92,21 @@ macro_rules! hi_span_offset {
  }
  }};
 }
+
+///
+/// - `srcmap!(true)` for start (span.lo)
+/// - `srcmap!(false)` for end (span.hi)
+macro_rules! srcmap {
+ ($emitter:expr, $n:expr, true) => {{
+ let lo = $n.span_lo();
+ if !lo.is_dummy() {
+ $emitter.wr.add_srcmap(lo)?;
+ }
+ }};
+ ($emitter:expr, $n:expr, false) => {
+ let hi = $n.span_hi();
+ if !hi.is_dummy() {
+ $emitter.wr.add_srcmap(hi)?;
+ }
+ };
+}

crates/swc_css_codegen/src/writer/basic.rs

@@ -229,6 +229,34 @@ where
  Ok(())
  }
 
+ fn write_comment(&mut self, s: &str) -> Result {
+ self.write(None, s)?;
+
+ {
+ let line_start_of_s = compute_line_starts(s);
+
+ if line_start_of_s.len() > 1 {
+ self.line = self.line + line_start_of_s.len() - 1;
+
+ let last_line_byte_index = line_start_of_s.last().cloned().unwrap_or(0);
+
+ self.col = s[last_line_byte_index..].chars().count();
+ }
+ }
+
+ Ok(())
+ }
+
+ fn add_srcmap(&mut self, pos: BytePos) -> Result {
+ if self.line_start {
+ self.pending_srcmap = Some(pos);
+ } else {
+ self.srcmap(pos);
+ }
+
+ Ok(())
+ }
+
  fn increase_indent(&mut self) {
  self.indent_level += 1;
  }

crates/swc_css_codegen/src/writer/mod.rs

@@ -1,7 +1,7 @@
 use std::fmt::Result;
 
 use auto_impl::auto_impl;
-use swc_common::Span;
+use swc_common::{BytePos, Span};
 
 pub mod basic;
 
@@ -15,6 +15,10 @@ pub trait CssWriter {
 
  fn write_str(&mut self, span: Span, s: &str) -> Result;
 
+ fn write_comment(&mut self, s: &str) -> Result;
+
+ fn add_srcmap(&mut self, pos: BytePos) -> Result;
+
  fn increase_indent(&mut self);
 
  fn decrease_indent(&mut self);