rust/src/source_map.rs
2020-03-26 21:25:34 -05:00

83 lines
2.9 KiB
Rust

//! 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 rustc_span::{BytePos, Span};
use crate::comment::FindUncommented;
use crate::config::file_lines::LineRange;
use crate::visitor::SnippetProvider;
pub(crate) 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 span_before_last(&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(crate) 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 SpanUtils for SnippetProvider {
fn span_after(&self, original: Span, needle: &str) -> BytePos {
self.opt_span_after(original, needle).unwrap_or_else(|| {
panic!(
"bad span: `{}`: `{}`",
needle,
self.span_to_snippet(original).unwrap()
)
})
}
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).unwrap_or_else(|| {
panic!(
"bad span: `{}`: `{}`",
needle,
self.span_to_snippet(original).unwrap()
)
})
}
fn span_before_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 - 1)
}
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))
}
}