src/rustfmt_diff.rs

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