rust/src/source_map.rs
2018-08-23 17:14:19 -04:00

93 lines
3.2 KiB
Rust

// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! This module contains utilities that work with the `SourceMap` from `libsyntax`/`syntex_syntax`.
//! This includes extension traits and methods for looking up spans and line ranges for AST nodes.
use config::file_lines::LineRange;
use syntax::source_map::{BytePos, SourceMap, Span};
use visitor::SnippetProvider;
use comment::FindUncommented;
pub trait SpanUtils {
fn span_after(&self, original: Span, needle: &str) -> BytePos;
fn span_after_last(&self, original: Span, needle: &str) -> BytePos;
fn span_before(&self, original: Span, needle: &str) -> BytePos;
fn opt_span_after(&self, original: Span, needle: &str) -> Option<BytePos>;
fn opt_span_before(&self, original: Span, needle: &str) -> Option<BytePos>;
}
pub trait LineRangeUtils {
/// Returns the `LineRange` that corresponds to `span` in `self`.
///
/// # Panics
///
/// Panics if `span` crosses a file boundary, which shouldn't happen.
fn lookup_line_range(&self, span: Span) -> LineRange;
}
impl<'a> SpanUtils for SnippetProvider<'a> {
fn span_after(&self, original: Span, needle: &str) -> BytePos {
self.opt_span_after(original, needle).expect("bad span")
}
fn span_after_last(&self, original: Span, needle: &str) -> BytePos {
let snippet = self.span_to_snippet(original).unwrap();
let mut offset = 0;
while let Some(additional_offset) = snippet[offset..].find_uncommented(needle) {
offset += additional_offset + needle.len();
}
original.lo() + BytePos(offset as u32)
}
fn span_before(&self, original: Span, needle: &str) -> BytePos {
self.opt_span_before(original, needle).expect(&format!(
"bad span: {}: {}",
needle,
self.span_to_snippet(original).unwrap()
))
}
fn opt_span_after(&self, original: Span, needle: &str) -> Option<BytePos> {
self.opt_span_before(original, needle)
.map(|bytepos| bytepos + BytePos(needle.len() as u32))
}
fn opt_span_before(&self, original: Span, needle: &str) -> Option<BytePos> {
let snippet = self.span_to_snippet(original)?;
let offset = snippet.find_uncommented(needle)?;
Some(original.lo() + BytePos(offset as u32))
}
}
impl LineRangeUtils for SourceMap {
fn lookup_line_range(&self, span: Span) -> LineRange {
let lo = self.lookup_line(span.lo()).unwrap();
let hi = self.lookup_line(span.hi()).unwrap();
debug_assert_eq!(
lo.fm.name, hi.fm.name,
"span crossed file boundary: lo: {:?}, hi: {:?}",
lo, hi
);
// Line numbers start at 1
LineRange {
file: lo.fm.clone(),
lo: lo.line + 1,
hi: hi.line + 1,
}
}
}