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-rw-r--r--crates/ra_hir_expand/src/diagnostics.rs85
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diff --git a/crates/ra_hir_expand/src/diagnostics.rs b/crates/ra_hir_expand/src/diagnostics.rs
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1//! Semantic errors and warnings.
2//!
3//! The `Diagnostic` trait defines a trait object which can represent any
4//! diagnostic.
5//!
6//! `DiagnosticSink` struct is used as an emitter for diagnostic. When creating
7//! a `DiagnosticSink`, you supply a callback which can react to a `dyn
8//! Diagnostic` or to any concrete diagnostic (downcasting is sued internally).
9//!
10//! Because diagnostics store file offsets, it's a bad idea to store them
11//! directly in salsa. For this reason, every hir subsytem defines it's own
12//! strongly-typed closed set of diagnostics which use hir ids internally, are
13//! stored in salsa and do *not* implement the `Diagnostic` trait. Instead, a
14//! subsystem provides a separate, non-query-based API which can walk all stored
15//! values and transform them into instances of `Diagnostic`.
16
17use std::{any::Any, fmt};
18
19use ra_syntax::{SyntaxNode, SyntaxNodePtr, TextRange};
20
21use crate::{db::AstDatabase, Source};
22
23pub trait Diagnostic: Any + Send + Sync + fmt::Debug + 'static {
24 fn message(&self) -> String;
25 fn source(&self) -> Source<SyntaxNodePtr>;
26 fn highlight_range(&self) -> TextRange {
27 self.source().ast.range()
28 }
29 fn as_any(&self) -> &(dyn Any + Send + 'static);
30}
31
32pub trait AstDiagnostic {
33 type AST;
34 fn ast(&self, db: &impl AstDatabase) -> Self::AST;
35}
36
37impl dyn Diagnostic {
38 pub fn syntax_node(&self, db: &impl AstDatabase) -> SyntaxNode {
39 let node = db.parse_or_expand(self.source().file_id).unwrap();
40 self.source().ast.to_node(&node)
41 }
42
43 pub fn downcast_ref<D: Diagnostic>(&self) -> Option<&D> {
44 self.as_any().downcast_ref()
45 }
46}
47
48pub struct DiagnosticSink<'a> {
49 callbacks: Vec<Box<dyn FnMut(&dyn Diagnostic) -> Result<(), ()> + 'a>>,
50 default_callback: Box<dyn FnMut(&dyn Diagnostic) + 'a>,
51}
52
53impl<'a> DiagnosticSink<'a> {
54 /// FIXME: split `new` and `on` into a separate builder type
55 pub fn new(cb: impl FnMut(&dyn Diagnostic) + 'a) -> DiagnosticSink<'a> {
56 DiagnosticSink { callbacks: Vec::new(), default_callback: Box::new(cb) }
57 }
58
59 pub fn on<D: Diagnostic, F: FnMut(&D) + 'a>(mut self, mut cb: F) -> DiagnosticSink<'a> {
60 let cb = move |diag: &dyn Diagnostic| match diag.downcast_ref::<D>() {
61 Some(d) => {
62 cb(d);
63 Ok(())
64 }
65 None => Err(()),
66 };
67 self.callbacks.push(Box::new(cb));
68 self
69 }
70
71 pub fn push(&mut self, d: impl Diagnostic) {
72 let d: &dyn Diagnostic = &d;
73 self._push(d);
74 }
75
76 fn _push(&mut self, d: &dyn Diagnostic) {
77 for cb in self.callbacks.iter_mut() {
78 match cb(d) {
79 Ok(()) => return,
80 Err(()) => (),
81 }
82 }
83 (self.default_callback)(d)
84 }
85}