313 lines
11 KiB
Rust
313 lines
11 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use std::borrow::Cow;
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use std::iter::repeat;
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use syntax::codemap::{BytePos, FileName, Pos, Span};
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use codemap::LineRangeUtils;
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use comment::{rewrite_comment, CodeCharKind, CommentCodeSlices};
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use config::WriteMode;
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use shape::{Indent, Shape};
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use utils::{count_newlines, last_line_width, mk_sp};
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use visitor::FmtVisitor;
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struct SnippetStatus {
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/// An offset to the current line from the beginnig of the original snippet.
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line_start: usize,
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/// A length of trailing whitespaces on the current line.
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last_wspace: Option<usize>,
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/// The current line number.
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cur_line: usize,
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}
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impl SnippetStatus {
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fn new(cur_line: usize) -> Self {
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SnippetStatus {
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line_start: 0,
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last_wspace: None,
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cur_line,
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}
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}
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}
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impl<'a> FmtVisitor<'a> {
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fn output_at_start(&self) -> bool {
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self.buffer.is_empty()
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}
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// TODO these format_missing methods are ugly. Refactor and add unit tests
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// for the central whitespace stripping loop.
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pub fn format_missing(&mut self, end: BytePos) {
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self.format_missing_inner(end, |this, last_snippet, _| this.push_str(last_snippet))
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}
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pub fn format_missing_with_indent(&mut self, end: BytePos) {
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let config = self.config;
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self.format_missing_inner(end, |this, last_snippet, snippet| {
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this.push_str(last_snippet.trim_right());
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if last_snippet == snippet && !this.output_at_start() {
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// No new lines in the snippet.
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this.push_str("\n");
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}
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let indent = this.block_indent.to_string(config);
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this.push_str(&indent);
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})
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}
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pub fn format_missing_no_indent(&mut self, end: BytePos) {
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self.format_missing_inner(end, |this, last_snippet, _| {
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this.push_str(last_snippet.trim_right());
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})
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}
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fn format_missing_inner<F: Fn(&mut FmtVisitor, &str, &str)>(
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&mut self,
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end: BytePos,
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process_last_snippet: F,
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) {
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let start = self.last_pos;
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if start == end {
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// Do nothing if this is the beginning of the file.
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if !self.output_at_start() {
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process_last_snippet(self, "", "");
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}
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return;
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}
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assert!(
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start < end,
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"Request to format inverted span: {:?} to {:?}",
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self.codemap.lookup_char_pos(start),
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self.codemap.lookup_char_pos(end)
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);
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self.last_pos = end;
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let span = mk_sp(start, end);
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let snippet = self.snippet(span);
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if snippet.trim().is_empty() && !out_of_file_lines_range!(self, span) {
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// Keep vertical spaces within range.
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self.push_vertical_spaces(count_newlines(snippet));
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process_last_snippet(self, "", snippet);
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} else {
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self.write_snippet(span, &process_last_snippet);
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}
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}
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fn push_vertical_spaces(&mut self, mut newline_count: usize) {
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// The buffer already has a trailing newline.
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let offset = if self.buffer.ends_with('\n') { 0 } else { 1 };
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let newline_upper_bound = self.config.blank_lines_upper_bound() + offset;
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let newline_lower_bound = self.config.blank_lines_lower_bound() + offset;
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if newline_count > newline_upper_bound {
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newline_count = newline_upper_bound;
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} else if newline_count < newline_lower_bound {
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newline_count = newline_lower_bound;
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}
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let blank_lines: String = repeat('\n').take(newline_count).collect();
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self.push_str(&blank_lines);
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}
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fn write_snippet<F>(&mut self, span: Span, process_last_snippet: F)
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where
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F: Fn(&mut FmtVisitor, &str, &str),
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{
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// Get a snippet from the file start to the span's hi without allocating.
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// We need it to determine what precedes the current comment. If the comment
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// follows code on the same line, we won't touch it.
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let big_span_lo = self.codemap.lookup_char_pos(span.lo()).file.start_pos;
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let local_begin = self.codemap.lookup_byte_offset(big_span_lo);
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let local_end = self.codemap.lookup_byte_offset(span.hi());
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let start_index = local_begin.pos.to_usize();
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let end_index = local_end.pos.to_usize();
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let big_snippet = &local_begin.fm.src.as_ref().unwrap()[start_index..end_index];
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let big_diff = (span.lo() - big_span_lo).to_usize();
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let snippet = self.snippet(span);
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debug!("write_snippet `{}`", snippet);
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self.write_snippet_inner(big_snippet, big_diff, snippet, span, process_last_snippet);
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}
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fn write_snippet_inner<F>(
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&mut self,
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big_snippet: &str,
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big_diff: usize,
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old_snippet: &str,
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span: Span,
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process_last_snippet: F,
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) where
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F: Fn(&mut FmtVisitor, &str, &str),
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{
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// Trim whitespace from the right hand side of each line.
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// Annoyingly, the library functions for splitting by lines etc. are not
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// quite right, so we must do it ourselves.
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let char_pos = self.codemap.lookup_char_pos(span.lo());
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let file_name = &char_pos.file.name;
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let mut status = SnippetStatus::new(char_pos.line);
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let snippet = &*match self.config.write_mode() {
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WriteMode::Coverage => replace_chars(old_snippet),
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_ => Cow::from(old_snippet),
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};
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for (kind, offset, subslice) in CommentCodeSlices::new(snippet) {
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debug!("{:?}: {:?}", kind, subslice);
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let newline_count = count_newlines(subslice);
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let within_file_lines_range = self.config.file_lines().intersects_range(
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file_name,
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status.cur_line,
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status.cur_line + newline_count,
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);
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if CodeCharKind::Comment == kind && within_file_lines_range {
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// 1: comment.
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self.process_comment(
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&mut status,
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snippet,
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&big_snippet[..(offset + big_diff)],
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offset,
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subslice,
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);
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} else if subslice.trim().is_empty() && newline_count > 0 && within_file_lines_range {
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// 2: blank lines.
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self.push_vertical_spaces(newline_count);
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status.cur_line += newline_count;
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status.line_start = offset + newline_count;
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} else {
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// 3: code which we failed to format or which is not within file-lines range.
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self.process_missing_code(&mut status, snippet, subslice, offset, file_name);
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}
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}
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process_last_snippet(self, &snippet[status.line_start..], snippet);
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}
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fn process_comment(
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&mut self,
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status: &mut SnippetStatus,
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snippet: &str,
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big_snippet: &str,
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offset: usize,
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subslice: &str,
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) {
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let last_char = big_snippet
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.chars()
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.rev()
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.skip_while(|rev_c| [' ', '\t'].contains(rev_c))
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.next();
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let fix_indent = last_char.map_or(true, |rev_c| ['{', '\n'].contains(&rev_c));
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let comment_indent = if fix_indent {
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if let Some('{') = last_char {
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self.push_str("\n");
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}
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let indent_str = self.block_indent.to_string(self.config);
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self.push_str(&indent_str);
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self.block_indent
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} else {
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self.push_str(" ");
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Indent::from_width(self.config, last_line_width(&self.buffer))
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};
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let comment_width = ::std::cmp::min(
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self.config.comment_width(),
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self.config.max_width() - self.block_indent.width(),
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);
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let comment_shape = Shape::legacy(comment_width, comment_indent);
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let comment_str = rewrite_comment(subslice, false, comment_shape, self.config)
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.unwrap_or_else(|| String::from(subslice));
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self.push_str(&comment_str);
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status.last_wspace = None;
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status.line_start = offset + subslice.len();
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if let Some('/') = subslice.chars().nth(1) {
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// check that there are no contained block comments
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if !subslice
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.split('\n')
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.map(|s| s.trim_left())
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.any(|s| s.len() >= 2 && &s[0..2] == "/*")
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{
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// Add a newline after line comments
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self.push_str("\n");
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}
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} else if status.line_start <= snippet.len() {
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// For other comments add a newline if there isn't one at the end already
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match snippet[status.line_start..].chars().next() {
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Some('\n') | Some('\r') => (),
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_ => self.push_str("\n"),
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}
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}
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status.cur_line += count_newlines(subslice);
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}
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fn process_missing_code(
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&mut self,
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status: &mut SnippetStatus,
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snippet: &str,
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subslice: &str,
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offset: usize,
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file_name: &FileName,
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) {
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for (mut i, c) in subslice.char_indices() {
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i += offset;
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if c == '\n' {
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let skip_this_line = !self.config
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.file_lines()
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.contains_line(file_name, status.cur_line);
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if skip_this_line {
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status.last_wspace = None;
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}
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if let Some(lw) = status.last_wspace {
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self.push_str(&snippet[status.line_start..lw]);
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self.push_str("\n");
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status.last_wspace = None;
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} else {
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self.push_str(&snippet[status.line_start..i + 1]);
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}
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status.cur_line += 1;
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status.line_start = i + 1;
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} else if c.is_whitespace() && status.last_wspace.is_none() {
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status.last_wspace = Some(i);
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} else if c == ';' && status.last_wspace.is_some() {
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status.line_start = i;
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status.last_wspace = None;
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} else {
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status.last_wspace = None;
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}
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}
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let remaining = snippet[status.line_start..subslice.len() + offset].trim();
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if !remaining.is_empty() {
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self.push_str(remaining);
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status.line_start = subslice.len() + offset;
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}
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}
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}
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fn replace_chars(string: &str) -> Cow<str> {
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Cow::from(
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string
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.chars()
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.map(|ch| if ch.is_whitespace() { ch } else { 'X' })
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.collect::<String>(),
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)
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}
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