miette/src/handlers/narratable.rs

419 lines
16 KiB
Rust

use std::fmt;
use unicode_width::{UnicodeWidthChar, UnicodeWidthStr};
use crate::diagnostic_chain::DiagnosticChain;
use crate::protocol::{Diagnostic, Severity};
use crate::{LabeledSpan, MietteError, ReportHandler, SourceCode, SourceSpan, SpanContents};
/**
[`ReportHandler`] that renders plain text and avoids extraneous graphics.
It's optimized for screen readers and braille users, but is also used in any
non-graphical environments, such as non-TTY output.
*/
#[derive(Debug, Clone)]
pub struct NarratableReportHandler {
context_lines: Option<usize>,
with_cause_chain: bool,
footer: Option<String>,
}
impl NarratableReportHandler {
/// Create a new [`NarratableReportHandler`]. There are no customization
/// options.
pub const fn new() -> Self {
Self {
footer: None,
context_lines: Some(1),
with_cause_chain: true,
}
}
/// Include the cause chain of the top-level error in the report, if
/// available.
pub const fn with_cause_chain(mut self) -> Self {
self.with_cause_chain = true;
self
}
/// Do not include the cause chain of the top-level error in the report.
pub const fn without_cause_chain(mut self) -> Self {
self.with_cause_chain = false;
self
}
/// Set the footer to be displayed at the end of the report.
pub fn with_footer(mut self, footer: String) -> Self {
self.footer = Some(footer);
self
}
/// Sets the number of lines of context to show around each error.
///
/// If `0`, then only the span content will be shown (equivalent to
/// `with_opt_context_lines(None)`).\
/// Use `with_opt_context_lines(Some(0))` if you want the whole line
/// containing the error without extra context.
pub fn with_context_lines(self, lines: usize) -> Self {
self.with_opt_context_lines((lines != 0).then_some(lines))
}
/// Sets the number of lines of context to show around each error.
///
/// `None` means only the span content (and possibly the content in between
/// multiple adjacent labels) will be shown.\
/// `Some(0)` will show the whole line containing the label.\
/// `Some(n)` will show the whole line plus n line before and after the label.
pub fn with_opt_context_lines(mut self, lines: Option<usize>) -> Self {
self.context_lines = lines;
self
}
}
impl Default for NarratableReportHandler {
fn default() -> Self {
Self::new()
}
}
impl NarratableReportHandler {
/// Render a [`Diagnostic`]. This function is mostly internal and meant to
/// be called by the toplevel [`ReportHandler`] handler, but is
/// made public to make it easier (possible) to test in isolation from
/// global state.
pub fn render_report(
&self,
f: &mut impl fmt::Write,
diagnostic: &(dyn Diagnostic),
) -> fmt::Result {
self.render_header(f, diagnostic)?;
if self.with_cause_chain {
self.render_causes(f, diagnostic)?;
}
let src = diagnostic.source_code();
self.render_snippets(f, diagnostic, src)?;
self.render_footer(f, diagnostic)?;
self.render_related(f, diagnostic, src)?;
if let Some(footer) = &self.footer {
writeln!(f, "{}", footer)?;
}
Ok(())
}
fn render_header(&self, f: &mut impl fmt::Write, diagnostic: &(dyn Diagnostic)) -> fmt::Result {
writeln!(f, "{}", diagnostic)?;
let severity = match diagnostic.severity() {
Some(Severity::Error) | None => "error",
Some(Severity::Warning) => "warning",
Some(Severity::Advice) => "advice",
};
writeln!(f, " Diagnostic severity: {}", severity)?;
Ok(())
}
fn render_causes(&self, f: &mut impl fmt::Write, diagnostic: &(dyn Diagnostic)) -> fmt::Result {
if let Some(cause_iter) = diagnostic
.diagnostic_source()
.map(DiagnosticChain::from_diagnostic)
.or_else(|| diagnostic.source().map(DiagnosticChain::from_stderror))
{
for error in cause_iter {
writeln!(f, " Caused by: {}", error)?;
}
}
Ok(())
}
fn render_footer(&self, f: &mut impl fmt::Write, diagnostic: &(dyn Diagnostic)) -> fmt::Result {
if let Some(help) = diagnostic.help() {
writeln!(f, "diagnostic help: {}", help)?;
}
if let Some(code) = diagnostic.code() {
writeln!(f, "diagnostic code: {}", code)?;
}
if let Some(url) = diagnostic.url() {
writeln!(f, "For more details, see:\n{}", url)?;
}
Ok(())
}
fn render_related(
&self,
f: &mut impl fmt::Write,
diagnostic: &(dyn Diagnostic),
parent_src: Option<&dyn SourceCode>,
) -> fmt::Result {
if let Some(related) = diagnostic.related() {
writeln!(f)?;
for rel in related {
match rel.severity() {
Some(Severity::Error) | None => write!(f, "Error: ")?,
Some(Severity::Warning) => write!(f, "Warning: ")?,
Some(Severity::Advice) => write!(f, "Advice: ")?,
};
self.render_header(f, rel)?;
writeln!(f)?;
self.render_causes(f, rel)?;
let src = rel.source_code().or(parent_src);
self.render_snippets(f, rel, src)?;
self.render_footer(f, rel)?;
self.render_related(f, rel, src)?;
}
}
Ok(())
}
fn render_snippets(
&self,
f: &mut impl fmt::Write,
diagnostic: &(dyn Diagnostic),
source_code: Option<&dyn SourceCode>,
) -> fmt::Result {
if let Some(source) = source_code {
if let Some(labels) = diagnostic.labels() {
let mut labels = labels.collect::<Vec<_>>();
labels.sort_unstable_by_key(|l| l.inner().offset());
if !labels.is_empty() {
let contents = labels
.iter()
.map(|label| {
source.read_span(label.inner(), self.context_lines, self.context_lines)
})
.collect::<Result<Vec<Box<dyn SpanContents<'_>>>, MietteError>>()
.map_err(|_| fmt::Error)?;
let mut contexts = Vec::new();
for (right, right_conts) in labels.iter().cloned().zip(contents.iter()) {
if contexts.is_empty() {
contexts.push((right, right_conts));
} else {
let (left, left_conts) = contexts.last().unwrap().clone();
let left_end = left.offset() + left.len();
let right_end = right.offset() + right.len();
if left_conts.line() + left_conts.line_count() >= right_conts.line() {
// The snippets will overlap, so we create one Big Chunky Boi
let new_span = LabeledSpan::new(
left.label().map(String::from),
left.offset(),
if right_end >= left_end {
// Right end goes past left end
right_end - left.offset()
} else {
// right is contained inside left
left.len()
},
);
if source
.read_span(
new_span.inner(),
self.context_lines,
self.context_lines,
)
.is_ok()
{
contexts.pop();
contexts.push((
new_span, // We'll throw this away later
left_conts,
));
} else {
contexts.push((right, right_conts));
}
} else {
contexts.push((right, right_conts));
}
}
}
for (ctx, _) in contexts {
self.render_context(f, source, &ctx, &labels[..])?;
}
}
}
}
Ok(())
}
fn render_context(
&self,
f: &mut impl fmt::Write,
source: &dyn SourceCode,
context: &LabeledSpan,
labels: &[LabeledSpan],
) -> fmt::Result {
let (contents, lines) = self.get_lines(source, context.inner())?;
write!(f, "Begin snippet")?;
if let Some(filename) = contents.name() {
write!(f, " for {}", filename,)?;
}
writeln!(
f,
" starting at line {}, column {}",
contents.line() + 1,
contents.column() + 1
)?;
writeln!(f)?;
for line in &lines {
writeln!(f, "snippet line {}: {}", line.line_number, line.text)?;
let relevant = labels
.iter()
.filter_map(|l| line.span_attach(l.inner()).map(|a| (a, l)));
for (attach, label) in relevant {
match attach {
SpanAttach::Contained { col_start, col_end } if col_start == col_end => {
write!(
f,
" label at line {}, column {}",
line.line_number, col_start,
)?;
}
SpanAttach::Contained { col_start, col_end } => {
write!(
f,
" label at line {}, columns {} to {}",
line.line_number, col_start, col_end,
)?;
}
SpanAttach::Starts { col_start } => {
write!(
f,
" label starting at line {}, column {}",
line.line_number, col_start,
)?;
}
SpanAttach::Ends { col_end } => {
write!(
f,
" label ending at line {}, column {}",
line.line_number, col_end,
)?;
}
}
if let Some(label) = label.label() {
write!(f, ": {}", label)?;
}
writeln!(f)?;
}
}
Ok(())
}
fn get_lines<'a>(
&'a self,
source: &'a dyn SourceCode,
context_span: &'a SourceSpan,
) -> Result<(Box<dyn SpanContents<'a> + 'a>, Vec<Line>), fmt::Error> {
let context_data = source
.read_span(context_span, self.context_lines, self.context_lines)
.map_err(|_| fmt::Error)?;
let context = std::str::from_utf8(context_data.data()).expect("Bad utf8 detected");
let lines = context
.split_inclusive('\n')
.enumerate()
.map(|(line_number, line)| {
// SAFETY:
// - it is safe to use `offset_from` on slices of an array per Rus design (max array size)
// (https://doc.rust-lang.org/stable/reference/types/numeric.html#machine-dependent-integer-types)
// - since `line` is a slice of `context`, the offset cannot be negative either
let offset = unsafe { line.as_ptr().offset_from(context.as_ptr()) } as usize;
let length = line.len();
// Strip the newline chars
let line = line
.strip_suffix('\n')
.and_then(|line| line.strip_suffix('\r').or(Some(line)))
.unwrap_or(line);
// End of the "file" if the end of the line is also the end of
// the context and we removed some characters (newline)
let at_end_of_file = (offset + length == context.len()) && (length != line.len());
Line {
line_number: context_data.line() + line_number + 1,
offset: context_data.span().offset() + offset,
text: line.to_string(),
at_end_of_file,
}
})
.collect::<Vec<_>>();
Ok((context_data, lines))
}
}
impl ReportHandler for NarratableReportHandler {
fn debug(&self, diagnostic: &(dyn Diagnostic), f: &mut fmt::Formatter<'_>) -> fmt::Result {
if f.alternate() {
return fmt::Debug::fmt(diagnostic, f);
}
self.render_report(f, diagnostic)
}
}
/*
Support types
*/
struct Line {
line_number: usize,
offset: usize,
text: String,
at_end_of_file: bool,
}
enum SpanAttach {
Contained { col_start: usize, col_end: usize },
Starts { col_start: usize },
Ends { col_end: usize },
}
/// Returns column at offset, and nearest boundary if offset is in the middle of
/// the character
fn safe_get_column(text: &str, offset: usize, start: bool) -> usize {
let mut column = text.get(0..offset).map(|s| s.width()).unwrap_or_else(|| {
let mut column = 0;
for (idx, c) in text.char_indices() {
if offset <= idx {
break;
}
column += c.width().unwrap_or(0);
}
column
});
if start {
// Offset are zero-based, so plus one
column += 1;
} // On the other hand for end span, offset refers for the next column
// So we should do -1. column+1-1 == column
column
}
impl Line {
fn span_attach(&self, span: &SourceSpan) -> Option<SpanAttach> {
let span_end = span.offset() + span.len();
let line_end = self.offset + self.text.len();
let start_after = span.offset() >= self.offset;
let end_before = self.at_end_of_file || span_end <= line_end;
if start_after && end_before {
let col_start = safe_get_column(&self.text, span.offset() - self.offset, true);
let col_end = if span.is_empty() {
col_start
} else {
// span_end refers to the next character after token
// while col_end refers to the exact character, so -1
safe_get_column(&self.text, span_end - self.offset, false)
};
return Some(SpanAttach::Contained { col_start, col_end });
}
if start_after && span.offset() <= line_end {
let col_start = safe_get_column(&self.text, span.offset() - self.offset, true);
return Some(SpanAttach::Starts { col_start });
}
if end_before && span_end >= self.offset {
let col_end = safe_get_column(&self.text, span_end - self.offset, false);
return Some(SpanAttach::Ends { col_end });
}
None
}
}