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