compiler/rustc_save_analysis/src/span_utils.rs

   1 use crate::generated_code;
   2 use rustc_data_structures::sync::Lrc;
   3 use rustc_lexer::{tokenize, TokenKind};
   4 use rustc_session::Session;
   5 use rustc_span::*;
   6
   7 #[derive(Clone)]
   8 pub struct SpanUtils<'a> {
   9     pub sess: &'a Session,
  10 }
  11
  12 impl<'a> SpanUtils<'a> {
  13     pub fn new(sess: &'a Session) -> SpanUtils<'a> {
  14         SpanUtils { sess }
  15     }
  16
  17     pub fn make_filename_string(&self, file: &SourceFile) -> String {
  18         match &file.name {
  19             FileName::Real(RealFileName::LocalPath(path)) => {
  20                 if path.is_absolute() {
  21                     self.sess.source_map().path_mapping().map_prefix(path).0.display().to_string()
  22                 } else {
  23                     self.sess
  24                         .opts
  25                         .working_dir
  26                         .remapped_path_if_available()
  27                         .join(&path)
  28                         .display()
  29                         .to_string()
  30                 }
  31             }
  32             filename => filename.prefer_remapped().to_string(),
  33         }
  34     }
  35
  36     pub fn snippet(&self, span: Span) -> String {
  37         match self.sess.source_map().span_to_snippet(span) {
  38             Ok(s) => s,
  39             Err(_) => String::new(),
  40         }
  41     }
  42
  43     /// Finds the span of `*` token withing the larger `span`.
  44     pub fn sub_span_of_star(&self, mut span: Span) -> Option<Span> {
  45         let begin = self.sess.source_map().lookup_byte_offset(span.lo());
  46         let end = self.sess.source_map().lookup_byte_offset(span.hi());
  47         // Make the range zero-length if the span is invalid.
  48         if begin.sf.start_pos != end.sf.start_pos {
  49             span = span.shrink_to_lo();
  50         }
  51
  52         let sf = Lrc::clone(&begin.sf);
  53
  54         self.sess.source_map().ensure_source_file_source_present(Lrc::clone(&sf));
  55         let src =
  56             sf.src.clone().or_else(|| sf.external_src.borrow().get_source().map(Lrc::clone))?;
  57         let to_index = |pos: BytePos| -> usize { (pos - sf.start_pos).0 as usize };
  58         let text = &src[to_index(span.lo())..to_index(span.hi())];
  59         let start_pos = {
  60             let mut pos = 0;
  61             tokenize(text)
  62                 .map(|token| {
  63                     let start = pos;
  64                     pos += token.len;
  65                     (start, token)
  66                 })
  67                 .find(|(_pos, token)| token.kind == TokenKind::Star)?
  68                 .0
  69         };
  70         let lo = span.lo() + BytePos(start_pos as u32);
  71         let hi = lo + BytePos(1);
  72         Some(span.with_lo(lo).with_hi(hi))
  73     }
  74
  75     /// Return true if the span is generated code, and
  76     /// it is not a subspan of the root callsite.
  77     ///
  78     /// Used to filter out spans of minimal value,
  79     /// such as references to macro internal variables.
  80     pub fn filter_generated(&self, span: Span) -> bool {
  81         if generated_code(span) {
  82             return true;
  83         }
  84
  85         //If the span comes from a fake source_file, filter it.
  86         !self.sess.source_map().lookup_char_pos(span.lo()).file.is_real_file()
  87     }
  88 }
  89
  90 macro_rules! filter {
  91     ($util: expr, $parent: expr) => {
  92         if $util.filter_generated($parent) {
  93             return None;
  94         }
  95     };
  96 }