compiler/rustc_errors/src/snippet.rs

   1 // Code for annotating snippets.
   2
   3 use crate::Level;
   4
   5 #[derive(Clone, Debug, PartialOrd, Ord, PartialEq, Eq)]
   6 pub struct Line {
   7     pub line_index: usize,
   8     pub annotations: Vec<Annotation>,
   9 }
  10
  11 #[derive(Clone, Debug, PartialOrd, Ord, PartialEq, Eq)]
  12 pub struct MultilineAnnotation {
  13     pub depth: usize,
  14     pub line_start: usize,
  15     pub line_end: usize,
  16     pub start_col: usize,
  17     pub end_col: usize,
  18     pub is_primary: bool,
  19     pub label: Option<String>,
  20     pub overlaps_exactly: bool,
  21 }
  22
  23 impl MultilineAnnotation {
  24     pub fn increase_depth(&mut self) {
  25         self.depth += 1;
  26     }
  27
  28     /// Compare two `MultilineAnnotation`s considering only the `Span` they cover.
  29     pub fn same_span(&self, other: &MultilineAnnotation) -> bool {
  30         self.line_start == other.line_start
  31             && self.line_end == other.line_end
  32             && self.start_col == other.start_col
  33             && self.end_col == other.end_col
  34     }
  35
  36     pub fn as_start(&self) -> Annotation {
  37         Annotation {
  38             start_col: self.start_col,
  39             end_col: self.start_col + 1,
  40             is_primary: self.is_primary,
  41             label: None,
  42             annotation_type: AnnotationType::MultilineStart(self.depth),
  43         }
  44     }
  45
  46     pub fn as_end(&self) -> Annotation {
  47         Annotation {
  48             start_col: self.end_col.saturating_sub(1),
  49             end_col: self.end_col,
  50             is_primary: self.is_primary,
  51             label: self.label.clone(),
  52             annotation_type: AnnotationType::MultilineEnd(self.depth),
  53         }
  54     }
  55
  56     pub fn as_line(&self) -> Annotation {
  57         Annotation {
  58             start_col: 0,
  59             end_col: 0,
  60             is_primary: self.is_primary,
  61             label: None,
  62             annotation_type: AnnotationType::MultilineLine(self.depth),
  63         }
  64     }
  65 }
  66
  67 #[derive(Clone, Debug, PartialOrd, Ord, PartialEq, Eq)]
  68 pub enum AnnotationType {
  69     /// Annotation under a single line of code
  70     Singleline,
  71
  72     /// Annotation enclosing the first and last character of a multiline span
  73     Multiline(MultilineAnnotation),
  74
  75     // The Multiline type above is replaced with the following three in order
  76     // to reuse the current label drawing code.
  77     //
  78     // Each of these corresponds to one part of the following diagram:
  79     //
  80     //     x |   foo(1 + bar(x,
  81     //       |  _________^              < MultilineStart
  82     //     x | |             y),        < MultilineLine
  83     //       | |______________^ label   < MultilineEnd
  84     //     x |       z);
  85     /// Annotation marking the first character of a fully shown multiline span
  86     MultilineStart(usize),
  87     /// Annotation marking the last character of a fully shown multiline span
  88     MultilineEnd(usize),
  89     /// Line at the left enclosing the lines of a fully shown multiline span
  90     // Just a placeholder for the drawing algorithm, to know that it shouldn't skip the first 4
  91     // and last 2 lines of code. The actual line is drawn in `emit_message_default` and not in
  92     // `draw_multiline_line`.
  93     MultilineLine(usize),
  94 }
  95
  96 #[derive(Clone, Debug, PartialOrd, Ord, PartialEq, Eq)]
  97 pub struct Annotation {
  98     /// Start column, 0-based indexing -- counting *characters*, not
  99     /// utf-8 bytes. Note that it is important that this field goes
 100     /// first, so that when we sort, we sort orderings by start
 101     /// column.
 102     pub start_col: usize,
 103
 104     /// End column within the line (exclusive)
 105     pub end_col: usize,
 106
 107     /// Is this annotation derived from primary span
 108     pub is_primary: bool,
 109
 110     /// Optional label to display adjacent to the annotation.
 111     pub label: Option<String>,
 112
 113     /// Is this a single line, multiline or multiline span minimized down to a
 114     /// smaller span.
 115     pub annotation_type: AnnotationType,
 116 }
 117
 118 impl Annotation {
 119     /// Whether this annotation is a vertical line placeholder.
 120     pub fn is_line(&self) -> bool {
 121         matches!(self.annotation_type, AnnotationType::MultilineLine(_))
 122     }
 123
 124     pub fn is_multiline(&self) -> bool {
 125         matches!(self.annotation_type,
 126             AnnotationType::Multiline(_)
 127             | AnnotationType::MultilineStart(_)
 128             | AnnotationType::MultilineLine(_)
 129             | AnnotationType::MultilineEnd(_))
 130     }
 131
 132     pub fn len(&self) -> usize {
 133         // Account for usize underflows
 134         if self.end_col > self.start_col {
 135             self.end_col - self.start_col
 136         } else {
 137             self.start_col - self.end_col
 138         }
 139     }
 140
 141     pub fn has_label(&self) -> bool {
 142         if let Some(ref label) = self.label {
 143             // Consider labels with no text as effectively not being there
 144             // to avoid weird output with unnecessary vertical lines, like:
 145             //
 146             //     X | fn foo(x: u32) {
 147             //       | -------^------
 148             //       | |      |
 149             //       | |
 150             //       |
 151             //
 152             // Note that this would be the complete output users would see.
 153             !label.is_empty()
 154         } else {
 155             false
 156         }
 157     }
 158
 159     pub fn takes_space(&self) -> bool {
 160         // Multiline annotations always have to keep vertical space.
 161         match self.annotation_type {
 162             AnnotationType::MultilineStart(_) | AnnotationType::MultilineEnd(_) => true,
 163             _ => false,
 164         }
 165     }
 166 }
 167
 168 #[derive(Debug)]
 169 pub struct StyledString {
 170     pub text: String,
 171     pub style: Style,
 172 }
 173
 174 #[derive(Copy, Clone, Debug, PartialEq, Hash, Encodable, Decodable)]
 175 pub enum Style {
 176     MainHeaderMsg,
 177     HeaderMsg,
 178     LineAndColumn,
 179     LineNumber,
 180     Quotation,
 181     UnderlinePrimary,
 182     UnderlineSecondary,
 183     LabelPrimary,
 184     LabelSecondary,
 185     NoStyle,
 186     Level(Level),
 187     Highlight,
 188 }