src/rustfmt_diff.rs

   1 use std::collections::VecDeque;
   2 use diff;
   3 use term;
   4
   5 #[derive(Debug, PartialEq)]
   6 pub enum DiffLine {
   7     Context(String),
   8     Expected(String),
   9     Resulting(String),
  10 }
  11
  12 #[derive(Debug, PartialEq)]
  13 pub struct Mismatch {
  14     pub line_number: u32,
  15     pub lines: Vec<DiffLine>,
  16 }
  17
  18 impl Mismatch {
  19     fn new(line_number: u32) -> Mismatch {
  20         Mismatch {
  21             line_number: line_number,
  22             lines: Vec::new(),
  23         }
  24     }
  25 }
  26
  27 // Produces a diff between the expected output and actual output of rustfmt.
  28 pub fn make_diff(expected: &str, actual: &str, context_size: usize) -> Vec<Mismatch> {
  29     let mut line_number = 1;
  30     let mut context_queue: VecDeque<&str> = VecDeque::with_capacity(context_size);
  31     let mut lines_since_mismatch = context_size + 1;
  32     let mut results = Vec::new();
  33     let mut mismatch = Mismatch::new(0);
  34
  35     for result in diff::lines(expected, actual) {
  36         match result {
  37             diff::Result::Left(str) => {
  38                 if lines_since_mismatch >= context_size {
  39                     results.push(mismatch);
  40                     mismatch = Mismatch::new(line_number - context_queue.len() as u32);
  41                 }
  42
  43                 while let Some(line) = context_queue.pop_front() {
  44                     mismatch.lines.push(DiffLine::Context(line.to_owned()));
  45                 }
  46
  47                 mismatch.lines.push(DiffLine::Resulting(str.to_owned()));
  48                 lines_since_mismatch = 0;
  49             }
  50             diff::Result::Right(str) => {
  51                 if lines_since_mismatch >= context_size {
  52                     results.push(mismatch);
  53                     mismatch = Mismatch::new(line_number - context_queue.len() as u32);
  54                 }
  55
  56                 while let Some(line) = context_queue.pop_front() {
  57                     mismatch.lines.push(DiffLine::Context(line.to_owned()));
  58                 }
  59
  60                 mismatch.lines.push(DiffLine::Expected(str.to_owned()));
  61                 line_number += 1;
  62                 lines_since_mismatch = 0;
  63             }
  64             diff::Result::Both(str, _) => {
  65                 if context_queue.len() >= context_size {
  66                     let _ = context_queue.pop_front();
  67                 }
  68
  69                 if lines_since_mismatch < context_size {
  70                     mismatch.lines.push(DiffLine::Context(str.to_owned()));
  71                 } else {
  72                     context_queue.push_back(str);
  73                 }
  74
  75                 line_number += 1;
  76                 lines_since_mismatch += 1;
  77             }
  78         }
  79     }
  80
  81     results.push(mismatch);
  82     results.remove(0);
  83
  84     results
  85 }
  86
  87 pub fn print_diff<F>(diff: Vec<Mismatch>, get_section_title: F)
  88     where F: Fn(u32) -> String
  89 {
  90     let mut t = term::stdout().unwrap();
  91
  92     for mismatch in diff {
  93         let title = get_section_title(mismatch.line_number);
  94         writeln!(t, "{}", title).unwrap();
  95
  96         for line in mismatch.lines {
  97             match line {
  98                 DiffLine::Context(ref str) => {
  99                     t.reset().unwrap();
 100                     writeln!(t, " {}⏎", str).unwrap();
 101                 }
 102                 DiffLine::Expected(ref str) => {
 103                     t.fg(term::color::GREEN).unwrap();
 104                     writeln!(t, "+{}⏎", str).unwrap();
 105                 }
 106                 DiffLine::Resulting(ref str) => {
 107                     t.fg(term::color::RED).unwrap();
 108                     writeln!(t, "-{}⏎", str).unwrap();
 109                 }
 110             }
 111         }
 112         t.reset().unwrap();
 113     }
 114 }