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 F: Fn(u32) -> String
  90 {
  91     match term::stdout() {
  92         Some(_) if isatty() => print_diff_fancy(diff, get_section_title, term::stdout().unwrap()),
  93         _ => print_diff_basic(diff, get_section_title),
  94     }
  95
  96     // isatty shamelessly adapted from cargo.
  97     #[cfg(unix)]
  98     fn isatty() -> bool {
  99         extern crate libc;
 100
 101         unsafe { libc::isatty(libc::STDOUT_FILENO) != 0 }
 102     }
 103     #[cfg(windows)]
 104     fn isatty() -> bool {
 105         extern crate kernel32;
 106         extern crate winapi;
 107
 108         unsafe {
 109             let handle = kernel32::GetStdHandle(winapi::winbase::STD_OUTPUT_HANDLE);
 110             let mut out = 0;
 111             kernel32::GetConsoleMode(handle, &mut out) != 0
 112         }
 113     }
 114 }
 115
 116 fn print_diff_fancy<F>(diff: Vec<Mismatch>,
 117                        get_section_title: F,
 118                        mut t: Box<term::Terminal<Output = io::Stdout>>)
 119     where F: Fn(u32) -> String
 120 {
 121     for mismatch in diff {
 122         let title = get_section_title(mismatch.line_number);
 123         writeln!(t, "{}", title).unwrap();
 124
 125         for line in mismatch.lines {
 126             match line {
 127                 DiffLine::Context(ref str) => {
 128                     t.reset().unwrap();
 129                     writeln!(t, " {}⏎", str).unwrap();
 130                 }
 131                 DiffLine::Expected(ref str) => {
 132                     t.fg(term::color::GREEN).unwrap();
 133                     writeln!(t, "+{}⏎", str).unwrap();
 134                 }
 135                 DiffLine::Resulting(ref str) => {
 136                     t.fg(term::color::RED).unwrap();
 137                     writeln!(t, "-{}⏎", str).unwrap();
 138                 }
 139             }
 140         }
 141         t.reset().unwrap();
 142     }
 143 }
 144
 145 pub fn print_diff_basic<F>(diff: Vec<Mismatch>, get_section_title: F)
 146     where F: Fn(u32) -> String
 147 {
 148     for mismatch in diff {
 149         let title = get_section_title(mismatch.line_number);
 150         println!("{}", title);
 151
 152         for line in mismatch.lines {
 153             match line {
 154                 DiffLine::Context(ref str) => {
 155                     println!(" {}⏎", str);
 156                 }
 157                 DiffLine::Expected(ref str) => {
 158                     println!("+{}⏎", str);
 159                 }
 160                 DiffLine::Resulting(ref str) => {
 161                     println!("-{}⏎", str);
 162                 }
 163             }
 164         }
 165     }
 166 }