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|
//! VFS stands for Virtual File System.
//!
//! When doing analysis, we don't want to do any IO, we want to keep all source
//! code in memory. However, the actual source code is stored on disk, so you
//! need to get it into the memory in the first place somehow. VFS is the
//! component which does this.
//!
//! It is also responsible for watching the disk for changes, and for merging
//! editor state (modified, unsaved files) with disk state.
//! TODO: Some LSP clients support watching the disk, so this crate should
//! to support custom watcher events (related to https://github.com/rust-analyzer/rust-analyzer/issues/131)
//!
//! VFS is based on a concept of roots: a set of directories on the file system
//! which are watched for changes. Typically, there will be a root for each
//! Cargo package.
mod io;
mod watcher;
use std::{
cmp::Reverse,
ffi::OsStr,
fmt, fs, mem,
path::{Path, PathBuf},
sync::Arc,
thread,
};
use crossbeam_channel::Receiver;
use ra_arena::{impl_arena_id, Arena, RawId};
use relative_path::RelativePathBuf;
use rustc_hash::{FxHashMap, FxHashSet};
use thread_worker::WorkerHandle;
use walkdir::DirEntry;
pub use crate::io::TaskResult as VfsTask;
pub use crate::watcher::{Watcher, WatcherChange};
/// `RootFilter` is a predicate that checks if a file can belong to a root. If
/// several filters match a file (nested dirs), the most nested one wins.
struct RootFilter {
root: PathBuf,
file_filter: fn(&Path) -> bool,
}
impl RootFilter {
fn new(root: PathBuf) -> RootFilter {
RootFilter {
root,
file_filter: has_rs_extension,
}
}
/// Check if this root can contain `path`. NB: even if this returns
/// true, the `path` might actually be conained in some nested root.
fn can_contain(&self, path: &Path) -> Option<RelativePathBuf> {
if !(self.file_filter)(path) {
return None;
}
let path = path.strip_prefix(&self.root).ok()?;
RelativePathBuf::from_path(path).ok()
}
}
pub(crate) fn has_rs_extension(p: &Path) -> bool {
p.extension() == Some(OsStr::new("rs"))
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct VfsRoot(pub RawId);
impl_arena_id!(VfsRoot);
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct VfsFile(pub RawId);
impl_arena_id!(VfsFile);
struct VfsFileData {
root: VfsRoot,
path: RelativePathBuf,
is_overlayed: bool,
text: Arc<String>,
}
pub struct Vfs {
roots: Arena<VfsRoot, RootFilter>,
files: Arena<VfsFile, VfsFileData>,
root2files: FxHashMap<VfsRoot, FxHashSet<VfsFile>>,
pending_changes: Vec<VfsChange>,
worker: io::Worker,
worker_handle: WorkerHandle,
watcher: Watcher,
}
impl fmt::Debug for Vfs {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.write_str("Vfs { ... }")
}
}
impl Vfs {
pub fn new(mut roots: Vec<PathBuf>) -> (Vfs, Vec<VfsRoot>) {
let (worker, worker_handle) = io::start();
let watcher = Watcher::start(worker.inp.clone()).unwrap(); // TODO return Result?
let mut res = Vfs {
roots: Arena::default(),
files: Arena::default(),
root2files: FxHashMap::default(),
worker,
worker_handle,
watcher,
pending_changes: Vec::new(),
};
// A hack to make nesting work.
roots.sort_by_key(|it| Reverse(it.as_os_str().len()));
for (i, path) in roots.iter().enumerate() {
let root = res.roots.alloc(RootFilter::new(path.clone()));
res.root2files.insert(root, Default::default());
let nested = roots[..i]
.iter()
.filter(|it| it.starts_with(path))
.map(|it| it.clone())
.collect::<Vec<_>>();
let filter = move |entry: &DirEntry| {
if entry.file_type().is_file() {
has_rs_extension(entry.path())
} else {
nested.iter().all(|it| it != entry.path())
}
};
let task = io::Task::AddRoot {
root,
path: path.clone(),
filter: Box::new(filter),
};
res.worker.inp.send(task).unwrap();
res.watcher.watch(path).unwrap();
}
let roots = res.roots.iter().map(|(id, _)| id).collect();
(res, roots)
}
pub fn root2path(&self, root: VfsRoot) -> PathBuf {
self.roots[root].root.clone()
}
pub fn path2file(&self, path: &Path) -> Option<VfsFile> {
if let Some((_root, _path, Some(file))) = self.find_root(path) {
return Some(file);
}
None
}
pub fn file2path(&self, file: VfsFile) -> PathBuf {
let rel_path = &self.files[file].path;
let root_path = &self.roots[self.files[file].root].root;
rel_path.to_path(root_path)
}
pub fn file_for_path(&self, path: &Path) -> Option<VfsFile> {
if let Some((_root, _path, Some(file))) = self.find_root(path) {
return Some(file);
}
None
}
pub fn load(&mut self, path: &Path) -> Option<VfsFile> {
if let Some((root, rel_path, file)) = self.find_root(path) {
return if let Some(file) = file {
Some(file)
} else {
let text = fs::read_to_string(path).unwrap_or_default();
let text = Arc::new(text);
let file = self.add_file(root, rel_path.clone(), Arc::clone(&text), false);
let change = VfsChange::AddFile {
file,
text,
root,
path: rel_path,
};
self.pending_changes.push(change);
Some(file)
};
}
None
}
pub fn task_receiver(&self) -> &Receiver<io::TaskResult> {
&self.worker.out
}
pub fn handle_task(&mut self, task: io::TaskResult) {
match task {
io::TaskResult::AddRoot(task) => {
let mut files = Vec::new();
// While we were scanning the root in the backgound, a file might have
// been open in the editor, so we need to account for that.
let exising = self.root2files[&task.root]
.iter()
.map(|&file| (self.files[file].path.clone(), file))
.collect::<FxHashMap<_, _>>();
for (path, text) in task.files {
if let Some(&file) = exising.get(&path) {
let text = Arc::clone(&self.files[file].text);
files.push((file, path, text));
continue;
}
let text = Arc::new(text);
let file = self.add_file(task.root, path.clone(), Arc::clone(&text), false);
files.push((file, path, text));
}
let change = VfsChange::AddRoot {
root: task.root,
files,
};
self.pending_changes.push(change);
}
io::TaskResult::HandleChange(change) => match &change {
watcher::WatcherChange::Create(path)
| watcher::WatcherChange::Remove(path)
| watcher::WatcherChange::Write(path) => {
if self.should_handle_change(&path) {
self.worker.inp.send(io::Task::LoadChange(change)).unwrap()
}
}
watcher::WatcherChange::Rescan => {
// TODO we should reload all files
}
},
io::TaskResult::LoadChange(None) => {}
io::TaskResult::LoadChange(Some(change)) => match change {
io::WatcherChangeData::Create { path, text }
| io::WatcherChangeData::Write { path, text } => {
if let Some((root, path, file)) = self.find_root(&path) {
if let Some(file) = file {
self.do_change_file(file, text, false);
} else {
self.do_add_file(root, path, text, false);
}
}
}
io::WatcherChangeData::Remove { path } => {
if let Some((root, path, file)) = self.find_root(&path) {
if let Some(file) = file {
self.do_remove_file(root, path, file, false);
}
}
}
},
}
}
fn should_handle_change(&self, path: &Path) -> bool {
if let Some((_root, _rel_path, file)) = self.find_root(&path) {
if let Some(file) = file {
if self.files[file].is_overlayed {
// file is overlayed
return false;
}
}
true
} else {
// file doesn't belong to any root
false
}
}
fn do_add_file(
&mut self,
root: VfsRoot,
path: RelativePathBuf,
text: String,
is_overlay: bool,
) -> Option<VfsFile> {
let text = Arc::new(text);
let file = self.add_file(root, path.clone(), text.clone(), is_overlay);
self.pending_changes.push(VfsChange::AddFile {
file,
root,
path,
text,
});
Some(file)
}
fn do_change_file(&mut self, file: VfsFile, text: String, is_overlay: bool) {
if !is_overlay && self.files[file].is_overlayed {
return;
}
let text = Arc::new(text);
self.change_file(file, text.clone(), is_overlay);
self.pending_changes
.push(VfsChange::ChangeFile { file, text });
}
fn do_remove_file(
&mut self,
root: VfsRoot,
path: RelativePathBuf,
file: VfsFile,
is_overlay: bool,
) {
if !is_overlay && self.files[file].is_overlayed {
return;
}
self.remove_file(file);
self.pending_changes
.push(VfsChange::RemoveFile { root, path, file });
}
pub fn add_file_overlay(&mut self, path: &Path, text: String) -> Option<VfsFile> {
if let Some((root, rel_path, file)) = self.find_root(path) {
if let Some(file) = file {
self.do_change_file(file, text, true);
Some(file)
} else {
self.do_add_file(root, rel_path, text, true)
}
} else {
None
}
}
pub fn change_file_overlay(&mut self, path: &Path, new_text: String) {
if let Some((_root, _path, file)) = self.find_root(path) {
let file = file.expect("can't change a file which wasn't added");
self.do_change_file(file, new_text, true);
}
}
pub fn remove_file_overlay(&mut self, path: &Path) -> Option<VfsFile> {
if let Some((root, path, file)) = self.find_root(path) {
let file = file.expect("can't remove a file which wasn't added");
let full_path = path.to_path(&self.roots[root].root);
if let Ok(text) = fs::read_to_string(&full_path) {
self.do_change_file(file, text, true);
} else {
self.do_remove_file(root, path, file, true);
}
Some(file)
} else {
None
}
}
pub fn commit_changes(&mut self) -> Vec<VfsChange> {
mem::replace(&mut self.pending_changes, Vec::new())
}
/// Sutdown the VFS and terminate the background watching thread.
pub fn shutdown(self) -> thread::Result<()> {
let _ = self.watcher.shutdown();
let _ = self.worker.shutdown();
self.worker_handle.shutdown()
}
fn add_file(
&mut self,
root: VfsRoot,
path: RelativePathBuf,
text: Arc<String>,
is_overlayed: bool,
) -> VfsFile {
let data = VfsFileData {
root,
path,
text,
is_overlayed,
};
let file = self.files.alloc(data);
self.root2files.get_mut(&root).unwrap().insert(file);
file
}
fn change_file(&mut self, file: VfsFile, new_text: Arc<String>, is_overlayed: bool) {
let mut file_data = &mut self.files[file];
file_data.text = new_text;
file_data.is_overlayed = is_overlayed;
}
fn remove_file(&mut self, file: VfsFile) {
//FIXME: use arena with removal
self.files[file].text = Default::default();
self.files[file].path = Default::default();
let root = self.files[file].root;
let removed = self.root2files.get_mut(&root).unwrap().remove(&file);
assert!(removed);
}
fn find_root(&self, path: &Path) -> Option<(VfsRoot, RelativePathBuf, Option<VfsFile>)> {
let (root, path) = self
.roots
.iter()
.find_map(|(root, data)| data.can_contain(path).map(|it| (root, it)))?;
let file = self.root2files[&root]
.iter()
.map(|&it| it)
.find(|&file| self.files[file].path == path);
Some((root, path, file))
}
}
#[derive(Debug, Clone)]
pub enum VfsChange {
AddRoot {
root: VfsRoot,
files: Vec<(VfsFile, RelativePathBuf, Arc<String>)>,
},
AddFile {
root: VfsRoot,
file: VfsFile,
path: RelativePathBuf,
text: Arc<String>,
},
RemoveFile {
root: VfsRoot,
file: VfsFile,
path: RelativePathBuf,
},
ChangeFile {
file: VfsFile,
text: Arc<String>,
},
}
|