src/librustc_errors/annotate_snippet_emitter_writer.rs

   1 //! Emit diagnostics using the `annotate-snippets` library
   2 //!
   3 //! This is the equivalent of `./emitter.rs` but making use of the
   4 //! [`annotate-snippets`][annotate_snippets] library instead of building the output ourselves.
   5 //!
   6 //! [annotate_snippets]: https://docs.rs/crate/annotate-snippets/
   7
   8 use syntax_pos::{SourceFile, MultiSpan, Loc};
   9 use crate::{
  10     Level, CodeSuggestion, DiagnosticBuilder, Emitter,
  11     SourceMapperDyn, SubDiagnostic, DiagnosticId
  12 };
  13 use crate::emitter::FileWithAnnotatedLines;
  14 use rustc_data_structures::sync::Lrc;
  15 use crate::snippet::Line;
  16 use annotate_snippets::snippet::*;
  17 use annotate_snippets::display_list::DisplayList;
  18 use annotate_snippets::formatter::DisplayListFormatter;
  19
  20
  21 /// Generates diagnostics using annotate-snippet
  22 pub struct AnnotateSnippetEmitterWriter {
  23     source_map: Option<Lrc<SourceMapperDyn>>,
  24     /// If true, hides the longer explanation text
  25     short_message: bool,
  26     /// If true, will normalize line numbers with `LL` to prevent noise in UI test diffs.
  27     ui_testing: bool,
  28 }
  29
  30 impl Emitter for AnnotateSnippetEmitterWriter {
  31     /// The entry point for the diagnostics generation
  32     fn emit_diagnostic(&mut self, db: &DiagnosticBuilder<'_>) {
  33         let primary_span = db.span.clone();
  34         let children = db.children.clone();
  35         // FIXME(#59346): Collect suggestions (see emitter.rs)
  36         let suggestions: &[_] = &[];
  37
  38         // FIXME(#59346): Add `fix_multispans_in_std_macros` function from emitter.rs
  39
  40         self.emit_messages_default(&db.level,
  41                                    db.message(),
  42                                    &db.code,
  43                                    &primary_span,
  44                                    &children,
  45                                    &suggestions);
  46     }
  47
  48     fn should_show_explain(&self) -> bool {
  49         !self.short_message
  50     }
  51 }
  52
  53 /// Collects all the data needed to generate the data structures needed for the
  54 /// `annotate-snippets` library.
  55 struct DiagnosticConverter<'a> {
  56     source_map: Option<Lrc<SourceMapperDyn>>,
  57     level: Level,
  58     message: String,
  59     code: Option<DiagnosticId>,
  60     msp: MultiSpan,
  61     #[allow(dead_code)]
  62     children: &'a [SubDiagnostic],
  63     #[allow(dead_code)]
  64     suggestions: &'a [CodeSuggestion]
  65 }
  66
  67 impl<'a>  DiagnosticConverter<'a> {
  68     /// Turns rustc Diagnostic information into a `annotate_snippets::snippet::Snippet`.
  69     fn to_annotation_snippet(&self) -> Option<Snippet> {
  70         if let Some(source_map) = &self.source_map {
  71             // Make sure our primary file comes first
  72             let primary_lo = if let Some(ref primary_span) =
  73                 self.msp.primary_span().as_ref() {
  74                 source_map.lookup_char_pos(primary_span.lo())
  75             } else {
  76                 // FIXME(#59346): Not sure when this is the case and what
  77                 // should be done if it happens
  78                 return None
  79             };
  80             let annotated_files = FileWithAnnotatedLines::collect_annotations(
  81                 &self.msp,
  82                 &self.source_map
  83             );
  84             let slices = self.slices_for_files(annotated_files, primary_lo);
  85
  86             Some(Snippet {
  87                 title: Some(Annotation {
  88                     label: Some(self.message.to_string()),
  89                     id: self.code.clone().map(|c| {
  90                         match c {
  91                             DiagnosticId::Error(val) | DiagnosticId::Lint(val) => val
  92                         }
  93                     }),
  94                     annotation_type: Self::annotation_type_for_level(self.level),
  95                 }),
  96                 footer: vec![],
  97                 slices,
  98             })
  99         } else {
 100             // FIXME(#59346): Is it ok to return None if there's no source_map?
 101             None
 102         }
 103     }
 104
 105     fn slices_for_files(
 106         &self,
 107         annotated_files: Vec<FileWithAnnotatedLines>,
 108         primary_lo: Loc
 109     ) -> Vec<Slice> {
 110         // FIXME(#59346): Provide a test case where `annotated_files` is > 1
 111         annotated_files.iter().flat_map(|annotated_file| {
 112             annotated_file.lines.iter().map(|line| {
 113                 let line_source = Self::source_string(annotated_file.file.clone(), &line);
 114                 Slice {
 115                     source: line_source,
 116                     line_start: line.line_index,
 117                     origin: Some(primary_lo.file.name.to_string()),
 118                     // FIXME(#59346): Not really sure when `fold` should be true or false
 119                     fold: false,
 120                     annotations: line.annotations.iter().map(|a| {
 121                         self.annotation_to_source_annotation(a.clone())
 122                     }).collect(),
 123                 }
 124             }).collect::<Vec<Slice>>()
 125         }).collect::<Vec<Slice>>()
 126     }
 127
 128     /// Turns a `crate::snippet::Annotation` into a `SourceAnnotation`
 129     fn annotation_to_source_annotation(
 130         &self,
 131         annotation: crate::snippet::Annotation
 132     ) -> SourceAnnotation {
 133         SourceAnnotation {
 134             range: (annotation.start_col, annotation.end_col),
 135             label: annotation.label.unwrap_or("".to_string()),
 136             annotation_type: Self::annotation_type_for_level(self.level)
 137         }
 138     }
 139
 140     /// Provides the source string for the given `line` of `file`
 141     fn source_string(
 142         file: Lrc<SourceFile>,
 143         line: &Line
 144     ) -> String {
 145         file.get_line(line.line_index - 1).map(|a| a.to_string()).unwrap_or(String::new())
 146     }
 147
 148     /// Maps `Diagnostic::Level` to `snippet::AnnotationType`
 149     fn annotation_type_for_level(level: Level) -> AnnotationType {
 150         match level {
 151             Level::Bug | Level::Fatal | Level::PhaseFatal | Level::Error => AnnotationType::Error,
 152             Level::Warning => AnnotationType::Warning,
 153             Level::Note => AnnotationType::Note,
 154             Level::Help => AnnotationType::Help,
 155             // FIXME(#59346): Not sure how to map these two levels
 156             Level::Cancelled | Level::FailureNote => AnnotationType::Error
 157         }
 158     }
 159 }
 160
 161 impl AnnotateSnippetEmitterWriter {
 162     pub fn new(
 163         source_map: Option<Lrc<SourceMapperDyn>>,
 164         short_message: bool
 165     ) -> Self {
 166         Self {
 167             source_map,
 168             short_message,
 169             ui_testing: false,
 170         }
 171     }
 172
 173     /// Allows to modify `Self` to enable or disable the `ui_testing` flag.
 174     ///
 175     /// If this is set to true, line numbers will be normalized as `LL` in the output.
 176     pub fn ui_testing(mut self, ui_testing: bool) -> Self {
 177         self.ui_testing = ui_testing;
 178         self
 179     }
 180
 181     fn emit_messages_default(
 182         &mut self,
 183         level: &Level,
 184         message: String,
 185         code: &Option<DiagnosticId>,
 186         msp: &MultiSpan,
 187         children: &[SubDiagnostic],
 188         suggestions: &[CodeSuggestion]
 189     ) {
 190         let converter = DiagnosticConverter {
 191             source_map: self.source_map.clone(),
 192             level: level.clone(),
 193             message,
 194             code: code.clone(),
 195             msp: msp.clone(),
 196             children,
 197             suggestions
 198         };
 199         if let Some(snippet) = converter.to_annotation_snippet() {
 200             let dl = DisplayList::from(snippet);
 201             let dlf = DisplayListFormatter::new(true, self.ui_testing);
 202             // FIXME(#59346): Figure out if we can _always_ print to stderr or not.
 203             // `emitter.rs` has the `Destination` enum that lists various possible output
 204             // destinations.
 205             eprintln!("{}", dlf.format(&dl));
 206         };
 207     }
 208 }