rust/src/missed_spans.rs
2015-09-26 13:58:12 +12:00

103 lines
4.1 KiB
Rust

// Copyright 2015 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.
use visitor::FmtVisitor;
use syntax::codemap::{self, BytePos};
impl<'a> FmtVisitor<'a> {
// TODO these format_missing methods are ugly. Refactor and add unit tests
// for the central whitespace stripping loop.
pub fn format_missing(&mut self, end: BytePos) {
self.format_missing_inner(end,
|this, last_snippet, _| this.buffer.push_str(last_snippet))
}
pub fn format_missing_with_indent(&mut self, end: BytePos) {
let config = self.config;
self.format_missing_inner(end,
|this, last_snippet, snippet| {
this.buffer.push_str(last_snippet.trim_right());
if last_snippet == snippet {
// No new lines in the snippet.
this.buffer.push_str("\n");
}
let indent = this.block_indent.to_string(config);
this.buffer.push_str(&indent);
})
}
fn format_missing_inner<F: Fn(&mut FmtVisitor, &str, &str)>(&mut self,
end: BytePos,
process_last_snippet: F) {
let start = self.last_pos;
debug!("format_missing_inner: {:?} to {:?}",
self.codemap.lookup_char_pos(start),
self.codemap.lookup_char_pos(end));
if start == end {
// Do nothing if this is the beginning of the file.
if start == self.codemap.lookup_char_pos(start).file.start_pos {
return;
}
process_last_snippet(self, "", "");
return;
}
assert!(start < end,
"Request to format inverted span: {:?} to {:?}",
self.codemap.lookup_char_pos(start),
self.codemap.lookup_char_pos(end));
self.last_pos = end;
let span = codemap::mk_sp(start, end);
let snippet = self.snippet(span);
self.write_snippet(&snippet, true, &process_last_snippet);
}
fn write_snippet<F: Fn(&mut FmtVisitor, &str, &str)>(&mut self,
snippet: &str,
last_snippet: bool,
process_last_snippet: F) {
// Trim whitespace from the right hand side of each line.
// Annoyingly, the library functions for splitting by lines etc. are not
// quite right, so we must do it ourselves.
let mut line_start = 0;
let mut last_wspace = None;
for (i, c) in snippet.char_indices() {
if c == '\n' {
if let Some(lw) = last_wspace {
self.buffer.push_str(&snippet[line_start..lw]);
self.buffer.push_str("\n");
} else {
self.buffer.push_str(&snippet[line_start..i+1]);
}
line_start = i + 1;
last_wspace = None;
} else {
if c.is_whitespace() {
if last_wspace.is_none() {
last_wspace = Some(i);
}
} else {
last_wspace = None;
}
}
}
if last_snippet {
process_last_snippet(self, &snippet[line_start..], snippet);
} else {
self.buffer.push_str(&snippet[line_start..]);
}
}
}