src/rustfmt_diff.rs

   1 use std::collections::VecDeque;
   2 use diff;
   3 use term;
   4 use std::io;
   5
   6 #[derive(Debug, PartialEq)]
   7 pub enum DiffLine {
   8     Context(String),
   9     Expected(String),
  10     Resulting(String),
  11 }
  12
  13 #[derive(Debug, PartialEq)]
  14 pub struct Mismatch {
  15     pub line_number: u32,
  16     pub lines: Vec<DiffLine>,
  17 }
  18
  19 impl Mismatch {
  20     fn new(line_number: u32) -> Mismatch {
  21         Mismatch {
  22             line_number: line_number,
  23             lines: Vec::new(),
  24         }
  25     }
  26 }
  27
  28 // Produces a diff between the expected output and actual output of rustfmt.
  29 pub fn make_diff(expected: &str, actual: &str, context_size: usize) -> Vec<Mismatch> {
  30     let mut line_number = 1;
  31     let mut context_queue: VecDeque<&str> = VecDeque::with_capacity(context_size);
  32     let mut lines_since_mismatch = context_size + 1;
  33     let mut results = Vec::new();
  34     let mut mismatch = Mismatch::new(0);
  35
  36     for result in diff::lines(expected, actual) {
  37         match result {
  38             diff::Result::Left(str) => {
  39                 if lines_since_mismatch >= context_size {
  40                     results.push(mismatch);
  41                     mismatch = Mismatch::new(line_number - context_queue.len() as u32);
  42                 }
  43
  44                 while let Some(line) = context_queue.pop_front() {
  45                     mismatch
  46                         .lines
  47                         .push(DiffLine::Context(line.to_owned()));
  48                 }
  49
  50                 mismatch
  51                     .lines
  52                     .push(DiffLine::Resulting(str.to_owned()));
  53                 lines_since_mismatch = 0;
  54             }
  55             diff::Result::Right(str) => {
  56                 if lines_since_mismatch >= context_size {
  57                     results.push(mismatch);
  58                     mismatch = Mismatch::new(line_number - context_queue.len() as u32);
  59                 }
  60
  61                 while let Some(line) = context_queue.pop_front() {
  62                     mismatch
  63                         .lines
  64                         .push(DiffLine::Context(line.to_owned()));
  65                 }
  66
  67                 mismatch
  68                     .lines
  69                     .push(DiffLine::Expected(str.to_owned()));
  70                 line_number += 1;
  71                 lines_since_mismatch = 0;
  72             }
  73             diff::Result::Both(str, _) => {
  74                 if context_queue.len() >= context_size {
  75                     let _ = context_queue.pop_front();
  76                 }
  77
  78                 if lines_since_mismatch < context_size {
  79                     mismatch
  80                         .lines
  81                         .push(DiffLine::Context(str.to_owned()));
  82                 } else {
  83                     context_queue.push_back(str);
  84                 }
  85
  86                 line_number += 1;
  87                 lines_since_mismatch += 1;
  88             }
  89         }
  90     }
  91
  92     results.push(mismatch);
  93     results.remove(0);
  94
  95     results
  96 }
  97
  98 pub fn print_diff<F>(diff: Vec<Mismatch>, get_section_title: F)
  99     where F: Fn(u32) -> String
 100 {
 101     match term::stdout() {
 102         Some(ref t) if isatty() && t.supports_color() => {
 103             print_diff_fancy(diff, get_section_title, term::stdout().unwrap())
 104         }
 105         _ => print_diff_basic(diff, get_section_title),
 106     }
 107
 108     // isatty shamelessly adapted from cargo.
 109     #[cfg(unix)]
 110     fn isatty() -> bool {
 111         extern crate libc;
 112
 113         unsafe { libc::isatty(libc::STDOUT_FILENO) != 0 }
 114     }
 115     #[cfg(windows)]
 116     fn isatty() -> bool {
 117         extern crate kernel32;
 118         extern crate winapi;
 119
 120         unsafe {
 121             let handle = kernel32::GetStdHandle(winapi::winbase::STD_OUTPUT_HANDLE);
 122             let mut out = 0;
 123             kernel32::GetConsoleMode(handle, &mut out) != 0
 124         }
 125     }
 126 }
 127
 128 fn print_diff_fancy<F>(diff: Vec<Mismatch>,
 129                        get_section_title: F,
 130                        mut t: Box<term::Terminal<Output = io::Stdout>>)
 131     where F: Fn(u32) -> String
 132 {
 133     for mismatch in diff {
 134         let title = get_section_title(mismatch.line_number);
 135         writeln!(t, "{}", title).unwrap();
 136
 137         for line in mismatch.lines {
 138             match line {
 139                 DiffLine::Context(ref str) => {
 140                     t.reset().unwrap();
 141                     writeln!(t, " {}⏎", str).unwrap();
 142                 }
 143                 DiffLine::Expected(ref str) => {
 144                     t.fg(term::color::GREEN).unwrap();
 145                     writeln!(t, "+{}⏎", str).unwrap();
 146                 }
 147                 DiffLine::Resulting(ref str) => {
 148                     t.fg(term::color::RED).unwrap();
 149                     writeln!(t, "-{}⏎", str).unwrap();
 150                 }
 151             }
 152         }
 153         t.reset().unwrap();
 154     }
 155 }
 156
 157 pub fn print_diff_basic<F>(diff: Vec<Mismatch>, get_section_title: F)
 158     where F: Fn(u32) -> String
 159 {
 160     for mismatch in diff {
 161         let title = get_section_title(mismatch.line_number);
 162         println!("{}", title);
 163
 164         for line in mismatch.lines {
 165             match line {
 166                 DiffLine::Context(ref str) => {
 167                     println!(" {}⏎", str);
 168                 }
 169                 DiffLine::Expected(ref str) => {
 170                     println!("+{}⏎", str);
 171                 }
 172                 DiffLine::Resulting(ref str) => {
 173                     println!("-{}⏎", str);
 174                 }
 175             }
 176         }
 177     }
 178 }