src/libsyntax/diagnostics/plugin.rs

   1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use std::cell::RefCell;
  12 use std::collections::BTreeMap;
  13 use std::env;
  14
  15 use ast;
  16 use ast::{Ident, Name, TokenTree};
  17 use codemap::Span;
  18 use ext::base::{ExtCtxt, MacEager, MacResult};
  19 use ext::build::AstBuilder;
  20 use parse::token;
  21 use ptr::P;
  22 use util::small_vector::SmallVector;
  23
  24 use diagnostics::metadata::output_metadata;
  25
  26 // Maximum width of any line in an extended error description (inclusive).
  27 const MAX_DESCRIPTION_WIDTH: usize = 80;
  28
  29 thread_local! {
  30     static REGISTERED_DIAGNOSTICS: RefCell<ErrorMap> = {
  31         RefCell::new(BTreeMap::new())
  32     }
  33 }
  34
  35 /// Error information type.
  36 pub struct ErrorInfo {
  37     pub description: Option<Name>,
  38     pub use_site: Option<Span>
  39 }
  40
  41 /// Mapping from error codes to metadata.
  42 pub type ErrorMap = BTreeMap<Name, ErrorInfo>;
  43
  44 fn with_registered_diagnostics<T, F>(f: F) -> T where
  45     F: FnOnce(&mut ErrorMap) -> T,
  46 {
  47     REGISTERED_DIAGNOSTICS.with(move |slot| {
  48         f(&mut *slot.borrow_mut())
  49     })
  50 }
  51
  52 pub fn expand_diagnostic_used<'cx>(ecx: &'cx mut ExtCtxt,
  53                                    span: Span,
  54                                    token_tree: &[TokenTree])
  55                                    -> Box<MacResult+'cx> {
  56     let code = match (token_tree.len(), token_tree.get(0)) {
  57         (1, Some(&ast::TtToken(_, token::Ident(code, _)))) => code,
  58         _ => unreachable!()
  59     };
  60
  61     with_registered_diagnostics(|diagnostics| {
  62         match diagnostics.get_mut(&code.name) {
  63             // Previously used errors.
  64             Some(&mut ErrorInfo { description: _, use_site: Some(previous_span) }) => {
  65                 ecx.span_warn(span, &format!(
  66                     "diagnostic code {} already used", code
  67                 ));
  68                 ecx.span_note(previous_span, "previous invocation");
  69             }
  70             // Newly used errors.
  71             Some(ref mut info) => {
  72                 info.use_site = Some(span);
  73             }
  74             // Unregistered errors.
  75             None => {
  76                 ecx.span_err(span, &format!(
  77                     "used diagnostic code {} not registered", code
  78                 ));
  79             }
  80         }
  81     });
  82     MacEager::expr(ecx.expr_tuple(span, Vec::new()))
  83 }
  84
  85 pub fn expand_register_diagnostic<'cx>(ecx: &'cx mut ExtCtxt,
  86                                        span: Span,
  87                                        token_tree: &[TokenTree])
  88                                        -> Box<MacResult+'cx> {
  89     let (code, description) = match (
  90         token_tree.len(),
  91         token_tree.get(0),
  92         token_tree.get(1),
  93         token_tree.get(2)
  94     ) {
  95         (1, Some(&ast::TtToken(_, token::Ident(ref code, _))), None, None) => {
  96             (code, None)
  97         },
  98         (3, Some(&ast::TtToken(_, token::Ident(ref code, _))),
  99             Some(&ast::TtToken(_, token::Comma)),
 100             Some(&ast::TtToken(_, token::Literal(token::StrRaw(description, _), None)))) => {
 101             (code, Some(description))
 102         }
 103         _ => unreachable!()
 104     };
 105
 106     // Check that the description starts and ends with a newline and doesn't
 107     // overflow the maximum line width.
 108     description.map(|raw_msg| {
 109         let msg = raw_msg.as_str();
 110         if !msg.starts_with("\n") || !msg.ends_with("\n") {
 111             ecx.span_err(span, &format!(
 112                 "description for error code {} doesn't start and end with a newline",
 113                 code
 114             ));
 115         }
 116
 117         // URLs can be unavoidably longer than the line limit, so we allow them.
 118         // Allowed format is: `[name]: https://www.rust-lang.org/`
 119         let is_url = |l: &str| l.starts_with('[') && l.contains("]:") && l.contains("http");
 120
 121         if msg.lines().any(|line| line.len() > MAX_DESCRIPTION_WIDTH && !is_url(line)) {
 122             ecx.span_err(span, &format!(
 123                 "description for error code {} contains a line longer than {} characters.\n\
 124                  if you're inserting a long URL use the footnote style to bypass this check.",
 125                 code, MAX_DESCRIPTION_WIDTH
 126             ));
 127         }
 128     });
 129     // Add the error to the map.
 130     with_registered_diagnostics(|diagnostics| {
 131         let info = ErrorInfo {
 132             description: description,
 133             use_site: None
 134         };
 135         if diagnostics.insert(code.name, info).is_some() {
 136             ecx.span_err(span, &format!(
 137                 "diagnostic code {} already registered", code
 138             ));
 139         }
 140     });
 141     let sym = Ident::new(token::gensym(&format!(
 142         "__register_diagnostic_{}", code
 143     )));
 144     MacEager::items(SmallVector::many(vec![
 145         ecx.item_mod(
 146             span,
 147             span,
 148             sym,
 149             Vec::new(),
 150             Vec::new()
 151         )
 152     ]))
 153 }
 154
 155 pub fn expand_build_diagnostic_array<'cx>(ecx: &'cx mut ExtCtxt,
 156                                           span: Span,
 157                                           token_tree: &[TokenTree])
 158                                           -> Box<MacResult+'cx> {
 159     assert_eq!(token_tree.len(), 3);
 160     let (crate_name, name) = match (&token_tree[0], &token_tree[2]) {
 161         (
 162             // Crate name.
 163             &ast::TtToken(_, token::Ident(ref crate_name, _)),
 164             // DIAGNOSTICS ident.
 165             &ast::TtToken(_, token::Ident(ref name, _))
 166         ) => (*&crate_name, name),
 167         _ => unreachable!()
 168     };
 169
 170     // Output error metadata to `tmp/extended-errors/<target arch>/<crate name>.json`
 171     let target_triple = env::var("CFG_COMPILER_HOST_TRIPLE")
 172         .ok().expect("unable to determine target arch from $CFG_COMPILER_HOST_TRIPLE");
 173
 174     with_registered_diagnostics(|diagnostics| {
 175         if let Err(e) = output_metadata(ecx,
 176                                         &target_triple,
 177                                         &crate_name.name.as_str(),
 178                                         &diagnostics) {
 179             ecx.span_bug(span, &format!(
 180                 "error writing metadata for triple `{}` and crate `{}`, error: {}, cause: {:?}",
 181                 target_triple, crate_name, e.description(), e.cause()
 182             ));
 183         }
 184     });
 185
 186     // Construct the output expression.
 187     let (count, expr) =
 188         with_registered_diagnostics(|diagnostics| {
 189             let descriptions: Vec<P<ast::Expr>> =
 190                 diagnostics.iter().filter_map(|(code, info)| {
 191                     info.description.map(|description| {
 192                         ecx.expr_tuple(span, vec![
 193                             ecx.expr_str(span, code.as_str()),
 194                             ecx.expr_str(span, description.as_str())
 195                         ])
 196                     })
 197                 }).collect();
 198             (descriptions.len(), ecx.expr_vec(span, descriptions))
 199         });
 200
 201     let static_ = ecx.lifetime(span, ecx.name_of("'static"));
 202     let ty_str = ecx.ty_rptr(
 203         span,
 204         ecx.ty_ident(span, ecx.ident_of("str")),
 205         Some(static_),
 206         ast::MutImmutable,
 207     );
 208
 209     let ty = ecx.ty(
 210         span,
 211         ast::TyFixedLengthVec(
 212             ecx.ty(
 213                 span,
 214                 ast::TyTup(vec![ty_str.clone(), ty_str])
 215             ),
 216             ecx.expr_usize(span, count),
 217         ),
 218     );
 219
 220     MacEager::items(SmallVector::many(vec![
 221         P(ast::Item {
 222             ident: name.clone(),
 223             attrs: Vec::new(),
 224             id: ast::DUMMY_NODE_ID,
 225             node: ast::ItemConst(
 226                 ty,
 227                 expr,
 228             ),
 229             vis: ast::Public,
 230             span: span,
 231         })
 232     ]))
 233 }