src/tools/tidy/src/style.rs

   1 //! Tidy check to enforce various stylistic guidelines on the Rust codebase.
   2 //!
   3 //! Example checks are:
   4 //!
   5 //! * No lines over 100 characters.
   6 //! * No tabs.
   7 //! * No trailing whitespace.
   8 //! * No CR characters.
   9 //! * No `TODO` or `XXX` directives.
  10 //! * No unexplained ` ```ignore ` or ` ```rust,ignore ` doc tests.
  11 //!
  12 //! A number of these checks can be opted-out of with various directives like
  13 //! `// ignore-tidy-linelength`.
  14
  15 use std::fs::File;
  16 use std::io::prelude::*;
  17 use std::path::Path;
  18
  19 const COLS: usize = 100;
  20
  21 const UNEXPLAINED_IGNORE_DOCTEST_INFO: &str = r#"unexplained "```ignore" doctest; try one:
  22
  23 * make the test actually pass, by adding necessary imports and declarations, or
  24 * use "```text", if the code is not Rust code, or
  25 * use "```compile_fail,Ennnn", if the code is expected to fail at compile time, or
  26 * use "```should_panic", if the code is expected to fail at run time, or
  27 * use "```no_run", if the code should type-check but not necessary linkable/runnable, or
  28 * explain it like "```ignore (cannot-test-this-because-xxxx)", if the annotation cannot be avoided.
  29
  30 "#;
  31
  32 const LLVM_UNREACHABLE_INFO: &str = r"\
  33 C++ code used llvm_unreachable, which triggers undefined behavior
  34 when executed when assertions are disabled.
  35 Use llvm::report_fatal_error for increased robustness.";
  36
  37 /// Parser states for `line_is_url`.
  38 #[derive(PartialEq)]
  39 #[allow(non_camel_case_types)]
  40 enum LIUState {
  41     EXP_COMMENT_START,
  42     EXP_LINK_LABEL_OR_URL,
  43     EXP_URL,
  44     EXP_END,
  45 }
  46
  47 /// Returns `true` if `line` appears to be a line comment containing an URL,
  48 /// possibly with a Markdown link label in front, and nothing else.
  49 /// The Markdown link label, if present, may not contain whitespace.
  50 /// Lines of this form are allowed to be overlength, because Markdown
  51 /// offers no way to split a line in the middle of a URL, and the lengths
  52 /// of URLs to external references are beyond our control.
  53 fn line_is_url(line: &str) -> bool {
  54     use self::LIUState::*;
  55     let mut state: LIUState = EXP_COMMENT_START;
  56
  57     for tok in line.split_whitespace() {
  58         match (state, tok) {
  59             (EXP_COMMENT_START, "//") => state = EXP_LINK_LABEL_OR_URL,
  60             (EXP_COMMENT_START, "///") => state = EXP_LINK_LABEL_OR_URL,
  61             (EXP_COMMENT_START, "//!") => state = EXP_LINK_LABEL_OR_URL,
  62
  63             (EXP_LINK_LABEL_OR_URL, w)
  64                 if w.len() >= 4 && w.starts_with('[') && w.ends_with("]:")
  65                 => state = EXP_URL,
  66
  67             (EXP_LINK_LABEL_OR_URL, w)
  68                 if w.starts_with("http://") || w.starts_with("https://")
  69                 => state = EXP_END,
  70
  71             (EXP_URL, w)
  72                 if w.starts_with("http://") || w.starts_with("https://") || w.starts_with("../")
  73                 => state = EXP_END,
  74
  75             (_, _) => return false,
  76         }
  77     }
  78
  79     state == EXP_END
  80 }
  81
  82 /// Returns `true` if `line` is allowed to be longer than the normal limit.
  83 /// Currently there is only one exception, for long URLs, but more
  84 /// may be added in the future.
  85 fn long_line_is_ok(line: &str) -> bool {
  86     if line_is_url(line) {
  87         return true;
  88     }
  89
  90     false
  91 }
  92
  93 pub fn check(path: &Path, bad: &mut bool) {
  94     let mut contents = String::new();
  95     super::walk(path, &mut super::filter_dirs, &mut |file| {
  96         let filename = file.file_name().unwrap().to_string_lossy();
  97         let extensions = [".rs", ".py", ".js", ".sh", ".c", ".cpp", ".h"];
  98         if extensions.iter().all(|e| !filename.ends_with(e)) ||
  99            filename.starts_with(".#") {
 100             return
 101         }
 102
 103         contents.truncate(0);
 104         t!(t!(File::open(file), file).read_to_string(&mut contents));
 105
 106         if contents.is_empty() {
 107             tidy_error!(bad, "{}: empty file", file.display());
 108         }
 109
 110         let skip_cr = contents.contains("ignore-tidy-cr");
 111         let skip_tab = contents.contains("ignore-tidy-tab");
 112         let skip_length = contents.contains("ignore-tidy-linelength");
 113         let skip_end_whitespace = contents.contains("ignore-tidy-end-whitespace");
 114         let skip_copyright = contents.contains("ignore-tidy-copyright");
 115         let mut trailing_new_lines = 0;
 116         for (i, line) in contents.split('\n').enumerate() {
 117             let mut err = |msg: &str| {
 118                 tidy_error!(bad, "{}:{}: {}", file.display(), i + 1, msg);
 119             };
 120             if !skip_length && line.chars().count() > COLS
 121                 && !long_line_is_ok(line) {
 122                     err(&format!("line longer than {} chars", COLS));
 123             }
 124             if !skip_tab && line.contains('\t') {
 125                 err("tab character");
 126             }
 127             if !skip_end_whitespace && (line.ends_with(' ') || line.ends_with('\t')) {
 128                 err("trailing whitespace");
 129             }
 130             if !skip_cr && line.contains('\r') {
 131                 err("CR character");
 132             }
 133             if filename != "style.rs" {
 134                 if line.contains("TODO") {
 135                     err("TODO is deprecated; use FIXME")
 136                 }
 137                 if line.contains("//") && line.contains(" XXX") {
 138                     err("XXX is deprecated; use FIXME")
 139                 }
 140             }
 141             if !skip_copyright && (line.starts_with("// Copyright") ||
 142                                    line.starts_with("# Copyright") ||
 143                                    line.starts_with("Copyright"))
 144                                && (line.contains("Rust Developers") ||
 145                                    line.contains("Rust Project Developers")) {
 146                 err("copyright notices attributed to the Rust Project Developers are deprecated");
 147             }
 148             if line.ends_with("```ignore") || line.ends_with("```rust,ignore") {
 149                 err(UNEXPLAINED_IGNORE_DOCTEST_INFO);
 150             }
 151             if filename.ends_with(".cpp") && line.contains("llvm_unreachable") {
 152                 err(LLVM_UNREACHABLE_INFO);
 153             }
 154             if line.is_empty() {
 155                 trailing_new_lines += 1;
 156             } else {
 157                 trailing_new_lines = 0;
 158             }
 159         }
 160         match trailing_new_lines {
 161             0 => tidy_error!(bad, "{}: missing trailing newline", file.display()),
 162             1 | 2 => {}
 163             n => tidy_error!(bad, "{}: too many trailing newlines ({})", file.display(), n),
 164         };
 165     })
 166 }