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::collections::BTreeMap;
  12 use std::env;
  13
  14 use ast;
  15 use ast::{Ident, Name};
  16 use codemap;
  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::{keywords, 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 /// Error information type.
  34 pub struct ErrorInfo {
  35     pub description: Option<Name>,
  36     pub use_site: Option<Span>
  37 }
  38
  39 /// Mapping from error codes to metadata.
  40 pub type ErrorMap = BTreeMap<Name, ErrorInfo>;
  41
  42 pub fn expand_diagnostic_used<'cx>(ecx: &'cx mut ExtCtxt,
  43                                    span: Span,
  44                                    token_tree: &[TokenTree])
  45                                    -> Box<MacResult+'cx> {
  46     let code = match (token_tree.len(), token_tree.get(0)) {
  47         (1, Some(&TokenTree::Token(_, token::Ident(code, _)))) => code,
  48         _ => unreachable!()
  49     };
  50
  51     ecx.parse_sess.registered_diagnostics.with_lock(|diagnostics| {
  52         match diagnostics.get_mut(&code.name) {
  53             // Previously used errors.
  54             Some(&mut ErrorInfo { description: _, use_site: Some(previous_span) }) => {
  55                 ecx.struct_span_warn(span, &format!(
  56                     "diagnostic code {} already used", code
  57                 )).span_note(previous_span, "previous invocation")
  58                   .emit();
  59             }
  60             // Newly used errors.
  61             Some(ref mut info) => {
  62                 info.use_site = Some(span);
  63             }
  64             // Unregistered errors.
  65             None => {
  66                 ecx.span_err(span, &format!(
  67                     "used diagnostic code {} not registered", code
  68                 ));
  69             }
  70         }
  71     });
  72     MacEager::expr(ecx.expr_tuple(span, Vec::new()))
  73 }
  74
  75 pub fn expand_register_diagnostic<'cx>(ecx: &'cx mut ExtCtxt,
  76                                        span: Span,
  77                                        token_tree: &[TokenTree])
  78                                        -> Box<MacResult+'cx> {
  79     let (code, description) = match (
  80         token_tree.len(),
  81         token_tree.get(0),
  82         token_tree.get(1),
  83         token_tree.get(2)
  84     ) {
  85         (1, Some(&TokenTree::Token(_, token::Ident(ref code, _))), None, None) => {
  86             (code, None)
  87         },
  88         (3, Some(&TokenTree::Token(_, token::Ident(ref code, _))),
  89             Some(&TokenTree::Token(_, token::Comma)),
  90             Some(&TokenTree::Token(_, token::Literal(token::StrRaw(description, _), None)))) => {
  91             (code, Some(description))
  92         }
  93         _ => unreachable!()
  94     };
  95
  96     // Check that the description starts and ends with a newline and doesn't
  97     // overflow the maximum line width.
  98     description.map(|raw_msg| {
  99         let msg = raw_msg.as_str();
 100         if !msg.starts_with("\n") || !msg.ends_with("\n") {
 101             ecx.span_err(span, &format!(
 102                 "description for error code {} doesn't start and end with a newline",
 103                 code
 104             ));
 105         }
 106
 107         // URLs can be unavoidably longer than the line limit, so we allow them.
 108         // Allowed format is: `[name]: https://www.rust-lang.org/`
 109         let is_url = |l: &str| l.starts_with("[") && l.contains("]:") && l.contains("http");
 110
 111         if msg.lines().any(|line| line.len() > MAX_DESCRIPTION_WIDTH && !is_url(line)) {
 112             ecx.span_err(span, &format!(
 113                 "description for error code {} contains a line longer than {} characters.\n\
 114                  if you're inserting a long URL use the footnote style to bypass this check.",
 115                 code, MAX_DESCRIPTION_WIDTH
 116             ));
 117         }
 118     });
 119     // Add the error to the map.
 120     ecx.parse_sess.registered_diagnostics.with_lock(|diagnostics| {
 121         let info = ErrorInfo {
 122             description,
 123             use_site: None
 124         };
 125         if diagnostics.insert(code.name, info).is_some() {
 126             ecx.span_err(span, &format!(
 127                 "diagnostic code {} already registered", code
 128             ));
 129         }
 130     });
 131     let sym = Ident::with_empty_ctxt(Symbol::gensym(&format!(
 132         "__register_diagnostic_{}", code
 133     )));
 134     MacEager::items(SmallVector::many(vec![
 135         ecx.item_mod(
 136             span,
 137             span,
 138             sym,
 139             Vec::new(),
 140             Vec::new()
 141         )
 142     ]))
 143 }
 144
 145 pub fn expand_build_diagnostic_array<'cx>(ecx: &'cx mut ExtCtxt,
 146                                           span: Span,
 147                                           token_tree: &[TokenTree])
 148                                           -> Box<MacResult+'cx> {
 149     assert_eq!(token_tree.len(), 3);
 150     let (crate_name, name) = match (&token_tree[0], &token_tree[2]) {
 151         (
 152             // Crate name.
 153             &TokenTree::Token(_, token::Ident(ref crate_name, _)),
 154             // DIAGNOSTICS ident.
 155             &TokenTree::Token(_, token::Ident(ref name, _))
 156         ) => (*&crate_name, name),
 157         _ => unreachable!()
 158     };
 159
 160     // Output error metadata to `tmp/extended-errors/<target arch>/<crate name>.json`
 161     if let Ok(target_triple) = env::var("CFG_COMPILER_HOST_TRIPLE") {
 162         ecx.parse_sess.registered_diagnostics.with_lock(|diagnostics| {
 163             if let Err(e) = output_metadata(ecx,
 164                                             &target_triple,
 165                                             &crate_name.as_str(),
 166                                             diagnostics) {
 167                 ecx.span_bug(span, &format!(
 168                     "error writing metadata for triple `{}` and crate `{}`, error: {}, \
 169                      cause: {:?}",
 170                     target_triple, crate_name, e.description(), e.cause()
 171                 ));
 172             }
 173         });
 174     } else {
 175         ecx.span_err(span, &format!(
 176             "failed to write metadata for crate `{}` because $CFG_COMPILER_HOST_TRIPLE is not set",
 177             crate_name));
 178     }
 179
 180     // Construct the output expression.
 181     let (count, expr) =
 182         ecx.parse_sess.registered_diagnostics.with_lock(|diagnostics| {
 183             let descriptions: Vec<P<ast::Expr>> =
 184                 diagnostics.iter().filter_map(|(&code, info)| {
 185                     info.description.map(|description| {
 186                         ecx.expr_tuple(span, vec![
 187                             ecx.expr_str(span, code),
 188                             ecx.expr_str(span, description)
 189                         ])
 190                     })
 191                 }).collect();
 192             (descriptions.len(), ecx.expr_vec(span, descriptions))
 193         });
 194
 195     let static_ = ecx.lifetime(span, keywords::StaticLifetime.ident());
 196     let ty_str = ecx.ty_rptr(
 197         span,
 198         ecx.ty_ident(span, ecx.ident_of("str")),
 199         Some(static_),
 200         ast::Mutability::Immutable,
 201     );
 202
 203     let ty = ecx.ty(
 204         span,
 205         ast::TyKind::Array(
 206             ecx.ty(
 207                 span,
 208                 ast::TyKind::Tup(vec![ty_str.clone(), ty_str])
 209             ),
 210             ast::AnonConst {
 211                 id: ast::DUMMY_NODE_ID,
 212                 value: ecx.expr_usize(span, count),
 213             },
 214         ),
 215     );
 216
 217     MacEager::items(SmallVector::many(vec![
 218         P(ast::Item {
 219             ident: *name,
 220             attrs: Vec::new(),
 221             id: ast::DUMMY_NODE_ID,
 222             node: ast::ItemKind::Const(
 223                 ty,
 224                 expr,
 225             ),
 226             vis: codemap::respan(span.shrink_to_lo(), ast::VisibilityKind::Public),
 227             span,
 228             tokens: None,
 229         })
 230     ]))
 231 }