--- /dev/null
+//! Utility types to support cancellation.
+//!
+//! In a typical IDE use-case, requests and modification happen concurrently, as
+//! in the following scenario:
+//!
+//! * user types a character,
+//! * a syntax highlighting process is started
+//! * user types next character, while syntax highlighting *is still in
+//! progress*.
+//!
+//! In this situation, we want to react to modification as quckly as possible.
+//! At the same time, in-progress results are not very interesting, because they
+//! are invalidated by the edit anyway. So, we first cancel all in-flight
+//! requests, and then apply modification knowing that it won't intrfere with
+//! any background processing (this bit is handled by salsa, see
+//! `BaseDatabase::check_canceled` method).
+
+use std::{
+ cmp,
+ hash::{Hash, Hasher},
+ sync::Arc,
+};
+
+use backtrace::Backtrace;
+use parking_lot::Mutex;
+
+/// An "error" signifing that the operation was canceled.
+#[derive(Clone)]
+pub struct Canceled {
+ backtrace: Arc<Mutex<Backtrace>>,
+}
+
+pub type Cancelable<T> = Result<T, Canceled>;
+
+impl Canceled {
+ pub(crate) fn new() -> Canceled {
+ let bt = Backtrace::new_unresolved();
+ Canceled {
+ backtrace: Arc::new(Mutex::new(bt)),
+ }
+ }
+}
+
+impl std::fmt::Display for Canceled {
+ fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+ fmt.write_str("canceled")
+ }
+}
+
+impl std::fmt::Debug for Canceled {
+ fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+ let mut bt = self.backtrace.lock();
+ let bt: &mut Backtrace = &mut *bt;
+ bt.resolve();
+ write!(fmt, "canceled at:\n{:?}", bt)
+ }
+}
+
+impl std::error::Error for Canceled {}
+
+impl PartialEq for Canceled {
+ fn eq(&self, _: &Canceled) -> bool {
+ true
+ }
+}
+
+impl Eq for Canceled {}
+
+impl Hash for Canceled {
+ fn hash<H: Hasher>(&self, hasher: &mut H) {
+ ().hash(hasher)
+ }
+}
+
+impl cmp::Ord for Canceled {
+ fn cmp(&self, _: &Canceled) -> cmp::Ordering {
+ cmp::Ordering::Equal
+ }
+}
+
+impl cmp::PartialOrd for Canceled {
+ fn partial_cmp(&self, other: &Canceled) -> Option<cmp::Ordering> {
+ Some(self.cmp(other))
+ }
+}
//! ra_db defines basic database traits. Concrete DB is defined by ra_analysis.
+mod cancelation;
mod syntax_ptr;
mod input;
mod loc2id;
pub mod mock;
use std::sync::Arc;
+
use ra_editor::LineIndex;
use ra_syntax::{TextUnit, SourceFileNode};
-#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
-pub struct Canceled;
-
-pub type Cancelable<T> = Result<T, Canceled>;
-
-impl std::fmt::Display for Canceled {
- fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
- fmt.write_str("canceled")
- }
-}
-
-impl std::error::Error for Canceled {}
-
pub use crate::{
+ cancelation::{Canceled, Cancelable},
syntax_ptr::LocalSyntaxPtr,
input::{
FilesDatabase, FileId, CrateId, SourceRoot, SourceRootId, CrateGraph,
pub trait BaseDatabase: salsa::Database {
fn check_canceled(&self) -> Cancelable<()> {
if self.salsa_runtime().is_current_revision_canceled() {
- Err(Canceled)
+ Err(Canceled::new())
} else {
Ok(())
}
projects / rust.git / commitdiff