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.lines.push(DiffLine::Context(line.to_owned()));
  46                 }
  47
  48                 mismatch.lines.push(DiffLine::Resulting(str.to_owned()));
  49                 lines_since_mismatch = 0;
  50             }
  51             diff::Result::Right(str) => {
  52                 if lines_since_mismatch >= context_size {
  53                     results.push(mismatch);
  54                     mismatch = Mismatch::new(line_number - context_queue.len() as u32);
  55                 }
  56
  57                 while let Some(line) = context_queue.pop_front() {
  58                     mismatch.lines.push(DiffLine::Context(line.to_owned()));
  59                 }
  60
  61                 mismatch.lines.push(DiffLine::Expected(str.to_owned()));
  62                 line_number += 1;
  63                 lines_since_mismatch = 0;
  64             }
  65             diff::Result::Both(str, _) => {
  66                 if context_queue.len() >= context_size {
  67                     let _ = context_queue.pop_front();
  68                 }
  69
  70                 if lines_since_mismatch < context_size {
  71                     mismatch.lines.push(DiffLine::Context(str.to_owned()));
  72                 } else {
  73                     context_queue.push_back(str);
  74                 }
  75
  76                 line_number += 1;
  77                 lines_since_mismatch += 1;
  78             }
  79         }
  80     }
  81
  82     results.push(mismatch);
  83     results.remove(0);
  84
  85     results
  86 }
  87
  88 pub fn print_diff<F>(diff: Vec<Mismatch>, get_section_title: F)
  89 where
  90     F: Fn(u32) -> String,
  91 {
  92     match term::stdout() {
  93         Some(ref t) if isatty() && t.supports_color() => {
  94             print_diff_fancy(diff, get_section_title, term::stdout().unwrap())
  95         }
  96         _ => print_diff_basic(diff, get_section_title),
  97     }
  98
  99     // isatty shamelessly adapted from cargo.
 100     #[cfg(unix)]
 101     fn isatty() -> bool {
 102         extern crate libc;
 103
 104         unsafe { libc::isatty(libc::STDOUT_FILENO) != 0 }
 105     }
 106     #[cfg(windows)]
 107     fn isatty() -> bool {
 108         extern crate kernel32;
 109         extern crate winapi;
 110
 111         unsafe {
 112             let handle = kernel32::GetStdHandle(winapi::winbase::STD_OUTPUT_HANDLE);
 113             let mut out = 0;
 114             kernel32::GetConsoleMode(handle, &mut out) != 0
 115         }
 116     }
 117 }
 118
 119 fn print_diff_fancy<F>(
 120     diff: Vec<Mismatch>,
 121     get_section_title: F,
 122     mut t: Box<term::Terminal<Output = io::Stdout>>,
 123 ) where
 124     F: Fn(u32) -> String,
 125 {
 126     for mismatch in diff {
 127         let title = get_section_title(mismatch.line_number);
 128         writeln!(t, "{}", title).unwrap();
 129
 130         for line in mismatch.lines {
 131             match line {
 132                 DiffLine::Context(ref str) => {
 133                     t.reset().unwrap();
 134                     writeln!(t, " {}⏎", str).unwrap();
 135                 }
 136                 DiffLine::Expected(ref str) => {
 137                     t.fg(term::color::GREEN).unwrap();
 138                     writeln!(t, "+{}⏎", str).unwrap();
 139                 }
 140                 DiffLine::Resulting(ref str) => {
 141                     t.fg(term::color::RED).unwrap();
 142                     writeln!(t, "-{}⏎", str).unwrap();
 143                 }
 144             }
 145         }
 146         t.reset().unwrap();
 147     }
 148 }
 149
 150 pub fn print_diff_basic<F>(diff: Vec<Mismatch>, get_section_title: F)
 151 where
 152     F: Fn(u32) -> String,
 153 {
 154     for mismatch in diff {
 155         let title = get_section_title(mismatch.line_number);
 156         println!("{}", title);
 157
 158         for line in mismatch.lines {
 159             match line {
 160                 DiffLine::Context(ref str) => {
 161                     println!(" {}⏎", str);
 162                 }
 163                 DiffLine::Expected(ref str) => {
 164                     println!("+{}⏎", str);
 165                 }
 166                 DiffLine::Resulting(ref str) => {
 167                     println!("-{}⏎", str);
 168                 }
 169             }
 170         }
 171     }
 172 }