//! Context for a diagnostic.
use crate::diagnostic::Span;
use alloc::{
string::{String, ToString},
vec::Vec,
};
#[derive(Debug, Clone)]
/// Context for a diagnostic.
pub struct Context {
/// The context for the diagnostic, sequential lines of the source where the last string is the
/// relevant line for the diagnostic. Each line is at most 100 characters wide
pub context: Vec<String>,
/// The span of the context relevant to the diagnostic.
pub span: Span,
/// The label for the span.
pub label: Option<String>,
/// How indented into the context the span starts.
pub span_indent: usize,
}
impl Context {
/// Create the context for a diagnostic from a span and the source file.
pub fn new(source: &str, span: Span) -> Self {
const MAX_LENGTH: usize = 100;
let context_end = span.column.saturating_sub(1) + span.length.min(MAX_LENGTH);
let context_start = span.column.saturating_sub(1);
let span_start = context_start
.saturating_sub(MAX_LENGTH.saturating_sub(context_end.saturating_sub(context_start)));
let span_end = span_start + MAX_LENGTH;
let mut context = Vec::with_capacity(3);
let lines: Vec<&str> = source.lines().collect();
for i in (1..4).rev() {
if let Some(index) = span.line.checked_sub(i)
&& let Some(line) = lines.get(index)
{
let line_context = line
.get(span_start..span_end.min(line.len()))
.unwrap_or_default();
context.push(line_context.to_string());
}
}
let span_indent = context_start.saturating_sub(span_start);
Self {
context,
span,
label: None,
span_indent,
}
}
/// Sets the label of the context.
pub fn label<S: ToString>(mut self, label: S) -> Self {
self.label = Some(label.to_string());
self
}
}
#[cfg(test)]
mod test {
use alloc::{string::String, vec, vec::Vec};
use crate::diagnostic::{Context, Span};
const SOURCE: &str = r#"use alloc::boxed::Box;
use core::{error::Error, fmt};
use ts_ansi::style::{BOLD, DEFAULT, RED, RESET};
/// An error report, displays the error stack of some error.
pub struct Report<'e> {
/// The error for this report.
pub source: Box<dyn Error + 'e>,
}
impl<'e> Report<'e> {
/// Create a new error report.
pub fn new<E: Error + 'e>(source: E) -> Self {
Self {
source: Box::new(source),
}
}
}
impl Error for Report<'static> {
fn source(&self) -> Option<&(dyn Error + 'static)> {
Some(self.source.as_ref())
}
}
impl fmt::Debug for Report<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{self}")
}
}
impl fmt::Display for Report<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut current_error = Some(self.source.as_ref());
let mut count = 1;
while let Some(error) = current_error {
writeln!(f, " {BOLD}{RED}{count}{DEFAULT}.{RESET} {error}")?;
count += 1;
current_error = error.source();
}
Ok(())
}
}"#;
const MINIFIED_SOURCE: &str = r#"async function Ui(n){return location.href=n,await mu()}function mu(){let n=t=>{setTimeout(()=>n(t),400)};return new Promise(n)}var br=class{element;contents;action;constructor(t,e){this.element=ht(`${t}/error`,HTMLElement),this.contents=ht(`${t}/error/content`,HTMLElement),this.action=e}clearError(){this.element.classList.add("collapse"),this.element.ariaHidden="true",this.contents.textContent=""}addError(t){if(this.contents.textContent===""){this.element.classList.remove("collapse"),this.element.ariaHidden="false",this.contents.textContent=`Could not ${this.action}: ${t}`;return}this.contents.textContent+=`, ${t}`}setSomethingWentWrong(){this.element.classList.remove("collapse"),this.element.ariaHidden="false",this.contents.textContent=`Something went wrong while trying to ${this.action}. Try again later.`}},Nr=class{input;error;constructor(t,e){this.input=ht(`${t}${e}/input`,HTMLInputElement),this.error=ht(`${t}${e}/error`,HTMLElement),this.input.addEventListener("input",()=>{this.input.setCustomValidity("")})}getValue(){return this.input.type==="checkbox"?this.input.checked?"checked":"unchecked":this.input.value}setLock(t){this.input.disabled=t}clearError(){this.input.setCustomValidity(""),this.error.classList.add("hidden"),this.error.ariaHidden="true",this.error.textContent="!"}addError(t){if(this.error.textContent==="!"){this.input.setCustomValidity(t),this.error.classList.remove("hidden"),this.error.ariaHidden="false",this.error.textContent=`Invalid value: ${t}`;return}this.error.textContent+=`, ${t}`,this.input.setCustomValidity(this.error.textContent??"Invalid value")}},ge=class{form;formError;submitButton;inputs;constructor(t,e,r){this.form=ht(t,HTMLFormElement),this.formError=new br(t,r),this.submitButton=ht(`${t}/submit`,HTMLButtonElement);let o=new Map;for(let i of e)o.set(i,new Nr(t,i));this.inputs=o}clearErrors(){this.formError.clearError();for(let t of this.inputs.values())t.clearError()}setLock(t){this.submitButton.disabled=t;for(let e of this.inputs.values())e.setLock(t)}setInputErrors(t){if(!t||t.length===0){this.formError.addError("an unknown field is invalid");return}for(let e of t){let r=this.inputs.get(e.pointer)??null;r?r.addError(e.detail):this.formError.addError(`field ${e.pointer} ${e.detail}`)}}getValues(){let t=new Map;for(let[e,r]of this.inputs)t.set(e,r.getValue());return t}};"#;
#[test]
fn handles_context() {
let span = Span::default().line(7).column(12).length(6);
let context = Context::new(SOURCE, span);
assert_eq!(
vec![
r#""#,
r#"/// An error report, displays the error stack of some error."#,
r#"pub struct Report<'e> {"#
],
context.context
);
let span = Span::default().line(36);
let context = Context::new(SOURCE, span);
assert_eq!(
vec![
r#" while let Some(error) = current_error {"#,
r#" writeln!(f, " {BOLD}{RED}{count}{DEFAULT}.{RESET} {error}")?;"#,
r#""#
],
context.context
);
let span = Span::default().line(999);
let context = Context::new(SOURCE, span);
assert_eq!(Vec::<String>::new(), context.context);
let span = Span::default().line(35).column(999).length(999);
let context = Context::new(SOURCE, span);
assert_eq!(vec![r#""#, r#""#, r#""#], context.context);
let span = Span::default().line(1).column(200).length(50);
let context = Context::new(MINIFIED_SOURCE, span);
assert_eq!(
vec![
r#"ontents;action;constructor(t,e){this.element=ht(`${t}/error`,HTMLElement),this.contents=ht(`${t}/err"#
],
context.context
);
}
}