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};
  17 use syntax_pos::Span;
  18 use ext::base::{ExtCtxt, MacEager, MacResult};
  19 use ext::build::AstBuilder;
  20 use parse::token;
  21 use ptr::P;
  22 use symbol::Symbol;
  23 use tokenstream::{TokenTree};
  24 use util::small_vector::SmallVector;
  25
  26 use diagnostics::metadata::output_metadata;
  27
  28 pub use errors::*;
  29
  30 // Maximum width of any line in an extended error description (inclusive).
  31 const MAX_DESCRIPTION_WIDTH: usize = 80;
  32
  33 thread_local! {
  34     static REGISTERED_DIAGNOSTICS: RefCell<ErrorMap> = {
  35         RefCell::new(BTreeMap::new())
  36     }
  37 }
  38
  39 /// Error information type.
  40 pub struct ErrorInfo {
  41     pub description: Option<Name>,
  42     pub use_site: Option<Span>
  43 }
  44
  45 /// Mapping from error codes to metadata.
  46 pub type ErrorMap = BTreeMap<Name, ErrorInfo>;
  47
  48 fn with_registered_diagnostics<T, F>(f: F) -> T where
  49     F: FnOnce(&mut ErrorMap) -> T,
  50 {
  51     REGISTERED_DIAGNOSTICS.with(move |slot| {
  52         f(&mut *slot.borrow_mut())
  53     })
  54 }
  55
  56 pub fn expand_diagnostic_used<'cx>(ecx: &'cx mut ExtCtxt,
  57                                    span: Span,
  58                                    token_tree: &[TokenTree])
  59                                    -> Box<MacResult+'cx> {
  60     let code = match (token_tree.len(), token_tree.get(0)) {
  61         (1, Some(&TokenTree::Token(_, token::Ident(code)))) => code,
  62         _ => unreachable!()
  63     };
  64
  65     with_registered_diagnostics(|diagnostics| {
  66         match diagnostics.get_mut(&code.name) {
  67             // Previously used errors.
  68             Some(&mut ErrorInfo { description: _, use_site: Some(previous_span) }) => {
  69                 ecx.struct_span_warn(span, &format!(
  70                     "diagnostic code {} already used", code
  71                 )).span_note(previous_span, "previous invocation")
  72                   .emit();
  73             }
  74             // Newly used errors.
  75             Some(ref mut info) => {
  76                 info.use_site = Some(span);
  77             }
  78             // Unregistered errors.
  79             None => {
  80                 ecx.span_err(span, &format!(
  81                     "used diagnostic code {} not registered", code
  82                 ));
  83             }
  84         }
  85     });
  86     MacEager::expr(ecx.expr_tuple(span, Vec::new()))
  87 }
  88
  89 pub fn expand_register_diagnostic<'cx>(ecx: &'cx mut ExtCtxt,
  90                                        span: Span,
  91                                        token_tree: &[TokenTree])
  92                                        -> Box<MacResult+'cx> {
  93     let (code, description) = match (
  94         token_tree.len(),
  95         token_tree.get(0),
  96         token_tree.get(1),
  97         token_tree.get(2)
  98     ) {
  99         (1, Some(&TokenTree::Token(_, token::Ident(ref code))), None, None) => {
 100             (code, None)
 101         },
 102         (3, Some(&TokenTree::Token(_, token::Ident(ref code))),
 103             Some(&TokenTree::Token(_, token::Comma)),
 104             Some(&TokenTree::Token(_, token::Literal(token::StrRaw(description, _), None)))) => {
 105             (code, Some(description))
 106         }
 107         _ => unreachable!()
 108     };
 109
 110     // Check that the description starts and ends with a newline and doesn't
 111     // overflow the maximum line width.
 112     description.map(|raw_msg| {
 113         let msg = raw_msg.as_str();
 114         if !msg.starts_with("\n") || !msg.ends_with("\n") {
 115             ecx.span_err(span, &format!(
 116                 "description for error code {} doesn't start and end with a newline",
 117                 code
 118             ));
 119         }
 120
 121         // URLs can be unavoidably longer than the line limit, so we allow them.
 122         // Allowed format is: `[name]: https://www.rust-lang.org/`
 123         let is_url = |l: &str| l.starts_with("[") && l.contains("]:") && l.contains("http");
 124
 125         if msg.lines().any(|line| line.len() > MAX_DESCRIPTION_WIDTH && !is_url(line)) {
 126             ecx.span_err(span, &format!(
 127                 "description for error code {} contains a line longer than {} characters.\n\
 128                  if you're inserting a long URL use the footnote style to bypass this check.",
 129                 code, MAX_DESCRIPTION_WIDTH
 130             ));
 131         }
 132     });
 133     // Add the error to the map.
 134     with_registered_diagnostics(|diagnostics| {
 135         let info = ErrorInfo {
 136             description: description,
 137             use_site: None
 138         };
 139         if diagnostics.insert(code.name, info).is_some() {
 140             ecx.span_err(span, &format!(
 141                 "diagnostic code {} already registered", code
 142             ));
 143         }
 144     });
 145     let sym = Ident::with_empty_ctxt(Symbol::gensym(&format!(
 146         "__register_diagnostic_{}", code
 147     )));
 148     MacEager::items(SmallVector::many(vec![
 149         ecx.item_mod(
 150             span,
 151             span,
 152             sym,
 153             Vec::new(),
 154             Vec::new()
 155         )
 156     ]))
 157 }
 158
 159 pub fn expand_build_diagnostic_array<'cx>(ecx: &'cx mut ExtCtxt,
 160                                           span: Span,
 161                                           token_tree: &[TokenTree])
 162                                           -> Box<MacResult+'cx> {
 163     assert_eq!(token_tree.len(), 3);
 164     let (crate_name, name) = match (&token_tree[0], &token_tree[2]) {
 165         (
 166             // Crate name.
 167             &TokenTree::Token(_, token::Ident(ref crate_name)),
 168             // DIAGNOSTICS ident.
 169             &TokenTree::Token(_, token::Ident(ref name))
 170         ) => (*&crate_name, name),
 171         _ => unreachable!()
 172     };
 173
 174     // Output error metadata to `tmp/extended-errors/<target arch>/<crate name>.json`
 175     if let Ok(target_triple) = env::var("CFG_COMPILER_HOST_TRIPLE") {
 176         with_registered_diagnostics(|diagnostics| {
 177             if let Err(e) = output_metadata(ecx,
 178                                             &target_triple,
 179                                             &crate_name.name.as_str(),
 180                                             diagnostics) {
 181                 ecx.span_bug(span, &format!(
 182                     "error writing metadata for triple `{}` and crate `{}`, error: {}, \
 183                      cause: {:?}",
 184                     target_triple, crate_name, e.description(), e.cause()
 185                 ));
 186             }
 187         });
 188     } else {
 189         ecx.span_err(span, &format!(
 190             "failed to write metadata for crate `{}` because $CFG_COMPILER_HOST_TRIPLE is not set",
 191             crate_name));
 192     }
 193
 194     // Construct the output expression.
 195     let (count, expr) =
 196         with_registered_diagnostics(|diagnostics| {
 197             let descriptions: Vec<P<ast::Expr>> =
 198                 diagnostics.iter().filter_map(|(&code, info)| {
 199                     info.description.map(|description| {
 200                         ecx.expr_tuple(span, vec![
 201                             ecx.expr_str(span, code),
 202                             ecx.expr_str(span, description)
 203                         ])
 204                     })
 205                 }).collect();
 206             (descriptions.len(), ecx.expr_vec(span, descriptions))
 207         });
 208
 209     let static_ = ecx.lifetime(span, ecx.name_of("'static"));
 210     let ty_str = ecx.ty_rptr(
 211         span,
 212         ecx.ty_ident(span, ecx.ident_of("str")),
 213         Some(static_),
 214         ast::Mutability::Immutable,
 215     );
 216
 217     let ty = ecx.ty(
 218         span,
 219         ast::TyKind::Array(
 220             ecx.ty(
 221                 span,
 222                 ast::TyKind::Tup(vec![ty_str.clone(), ty_str])
 223             ),
 224             ecx.expr_usize(span, count),
 225         ),
 226     );
 227
 228     MacEager::items(SmallVector::many(vec![
 229         P(ast::Item {
 230             ident: *name,
 231             attrs: Vec::new(),
 232             id: ast::DUMMY_NODE_ID,
 233             node: ast::ItemKind::Const(
 234                 ty,
 235                 expr,
 236             ),
 237             vis: ast::Visibility::Public,
 238             span: span,
 239         })
 240     ]))
 241 }