rust/crates/ra_db/src/lib.rs
2019-06-12 13:25:30 +03:00

108 lines
3.5 KiB
Rust

//! ra_db defines basic database traits. The concrete DB is defined by ra_ide_api.
mod cancellation;
mod input;
use std::{panic, sync::Arc};
use ra_syntax::{TextUnit, TextRange, SourceFile, Parse};
use relative_path::RelativePathBuf;
use ra_prof::profile;
pub use ::salsa as salsa;
pub use crate::{
cancellation::Canceled,
input::{
FileId, CrateId, SourceRoot, SourceRootId, CrateGraph, Dependency, Edition,
},
};
pub trait CheckCanceled {
/// Aborts current query if there are pending changes.
///
/// rust-analyzer needs to be able to answer semantic questions about the
/// code while the code is being modified. A common problem is that a
/// long-running query is being calculated when a new change arrives.
///
/// We can't just apply the change immediately: this will cause the pending
/// query to see inconsistent state (it will observe an absence of
/// repeatable read). So what we do is we **cancel** all pending queries
/// before applying the change.
///
/// We implement cancellation by panicking with a special value and catching
/// it on the API boundary. Salsa explicitly supports this use-case.
fn check_canceled(&self);
fn catch_canceled<F, T>(&self, f: F) -> Result<T, Canceled>
where
Self: Sized,
F: FnOnce(&Self) -> T + panic::UnwindSafe,
{
let this = panic::AssertUnwindSafe(self);
panic::catch_unwind(|| f(*this)).map_err(|err| match err.downcast::<Canceled>() {
Ok(canceled) => *canceled,
Err(payload) => panic::resume_unwind(payload),
})
}
}
impl<T: salsa::Database> CheckCanceled for T {
fn check_canceled(&self) {
if self.salsa_runtime().is_current_revision_canceled() {
Canceled::throw()
}
}
}
#[derive(Clone, Copy, Debug)]
pub struct FilePosition {
pub file_id: FileId,
pub offset: TextUnit,
}
#[derive(Clone, Copy, Debug)]
pub struct FileRange {
pub file_id: FileId,
pub range: TextRange,
}
pub const DEFAULT_LRU_CAP: usize = 128;
/// Database which stores all significant input facts: source code and project
/// model. Everything else in rust-analyzer is derived from these queries.
#[salsa::query_group(SourceDatabaseStorage)]
pub trait SourceDatabase: CheckCanceled + std::fmt::Debug {
/// Text of the file.
#[salsa::input]
fn file_text(&self, file_id: FileId) -> Arc<String>;
// Parses the file into the syntax tree.
#[salsa::invoke(parse_query)]
fn parse(&self, file_id: FileId) -> Parse;
/// Path to a file, relative to the root of its source root.
#[salsa::input]
fn file_relative_path(&self, file_id: FileId) -> RelativePathBuf;
/// Source root of the file.
#[salsa::input]
fn file_source_root(&self, file_id: FileId) -> SourceRootId;
/// Contents of the source root.
#[salsa::input]
fn source_root(&self, id: SourceRootId) -> Arc<SourceRoot>;
fn source_root_crates(&self, id: SourceRootId) -> Arc<Vec<CrateId>>;
/// The crate graph.
#[salsa::input]
fn crate_graph(&self) -> Arc<CrateGraph>;
}
fn source_root_crates(db: &impl SourceDatabase, id: SourceRootId) -> Arc<Vec<CrateId>> {
let root = db.source_root(id);
let graph = db.crate_graph();
let res =
root.files.values().filter_map(|&it| graph.crate_id_for_crate_root(it)).collect::<Vec<_>>();
Arc::new(res)
}
fn parse_query(db: &impl SourceDatabase, file_id: FileId) -> Parse {
let _p = profile("parse_query");
let text = db.file_text(file_id);
SourceFile::parse(&*text)
}