Merge #671

671: Makre VFS slightly less super obscure r=vemoo a=matklad

I've decided to better understand what we do in VFS, and this turns out to be really hard. Jugling threads and channels is one of the most unfortunately arcane bits of rust...

I had some success though by flattenning the structure so that all channel & thread creation routines are on one screen. 

r? @vemoo 

Co-authored-by: Aleksey Kladov <[email protected]>

1 files changed, 66 insertions, 80 deletions

diff --git a/crates/ra_vfs/src/lib.rs b/crates/ra_vfs/src/lib.rs
index 70a13f765..71a3f807d 100644
--- a/crates/ra_vfs/src/lib.rs
+++ b/crates/ra_vfs/src/lib.rs
@@ -18,94 +18,78 @@ mod io;
 use std::{
     cmp::Reverse,
     fmt, fs, mem,
-    ops::{Deref, DerefMut},
     path::{Path, PathBuf},
     sync::Arc,
     thread,
 };
 
 use crossbeam_channel::Receiver;
-use ra_arena::{impl_arena_id, Arena, RawId};
+use ra_arena::{impl_arena_id, Arena, RawId, map::ArenaMap};
 use relative_path::{Component, RelativePath, RelativePathBuf};
 use rustc_hash::{FxHashMap, FxHashSet};
-use walkdir::DirEntry;
 
 pub use crate::io::TaskResult as VfsTask;
 use io::{TaskResult, Worker};
 
-/// `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.
-pub(crate) struct RootFilter {
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct VfsRoot(pub RawId);
+impl_arena_id!(VfsRoot);
+
+/// Describes the contents of a single source root.
+///
+/// `RootConfig` can be thought of as a glob pattern like `src/**.rs` whihc
+/// specifes the source root or as a function whihc takes a `PathBuf` and
+/// returns `true` iff path belongs to the source root
+pub(crate) struct RootConfig {
     root: PathBuf,
-    filter: fn(&Path, &RelativePath) -> bool,
     excluded_dirs: Vec<PathBuf>,
 }
 
-impl RootFilter {
-    fn new(root: PathBuf, excluded_dirs: Vec<PathBuf>) -> RootFilter {
-        RootFilter {
+pub(crate) struct Roots {
+    roots: Arena<VfsRoot, Arc<RootConfig>>,
+}
+
+impl std::ops::Deref for Roots {
+    type Target = Arena<VfsRoot, Arc<RootConfig>>;
+    fn deref(&self) -> &Self::Target {
+        &self.roots
+    }
+}
+
+impl RootConfig {
+    fn new(root: PathBuf, excluded_dirs: Vec<PathBuf>) -> RootConfig {
+        RootConfig {
             root,
-            filter: default_filter,
             excluded_dirs,
         }
     }
-    /// Check if this root can contain `path`. NB: even if this returns
-    /// true, the `path` might actually be conained in some nested root.
-    pub(crate) fn can_contain(&self, path: &Path) -> Option<RelativePathBuf> {
-        let rel_path = path.strip_prefix(&self.root).ok()?;
-        let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
-        if !(self.filter)(path, rel_path.as_relative_path()) {
+    /// Cheks if root contains a path and returns a root-relative path.
+    pub(crate) fn contains(&self, path: &Path) -> Option<RelativePathBuf> {
+        // First, check excluded dirs
+        if self.excluded_dirs.iter().any(|it| path.starts_with(it)) {
             return None;
         }
-        Some(rel_path)
-    }
-
-    pub(crate) fn entry_filter<'a>(&'a self) -> impl FnMut(&DirEntry) -> bool + 'a {
-        move |entry: &DirEntry| {
-            if entry.file_type().is_dir() && self.excluded_dirs.iter().any(|it| it == entry.path())
-            {
-                // do not walk nested roots
-                false
-            } else {
-                self.can_contain(entry.path()).is_some()
-            }
-        }
-    }
-}
+        let rel_path = path.strip_prefix(&self.root).ok()?;
+        let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
 
-pub(crate) fn default_filter(path: &Path, rel_path: &RelativePath) -> bool {
-    if path.is_dir() {
+        // Ignore some common directories.
+        //
+        // FIXME: don't hard-code, specify at source-root creation time using
+        // gitignore
         for (i, c) in rel_path.components().enumerate() {
             if let Component::Normal(c) = c {
-                // TODO hardcoded for now
                 if (i == 0 && c == "target") || c == ".git" || c == "node_modules" {
-                    return false;
+                    return None;
                 }
             }
         }
-        true
-    } else {
-        rel_path.extension() == Some("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>,
-}
+        if path.is_file() && rel_path.extension() != Some("rs") {
+            return None;
+        }
 
-pub(crate) struct Roots {
-    roots: Arena<VfsRoot, Arc<RootFilter>>,
+        Some(rel_path)
+    }
 }
 
 impl Roots {
@@ -120,59 +104,61 @@ impl Roots {
                 .map(|it| it.clone())
                 .collect::<Vec<_>>();
 
-            let root_filter = Arc::new(RootFilter::new(path.clone(), nested_roots));
+            let config = Arc::new(RootConfig::new(path.clone(), nested_roots));
 
-            roots.alloc(root_filter.clone());
+            roots.alloc(config.clone());
         }
         Roots { roots }
     }
     pub(crate) fn find(&self, path: &Path) -> Option<(VfsRoot, RelativePathBuf)> {
         self.roots
             .iter()
-            .find_map(|(root, data)| data.can_contain(path).map(|it| (root, it)))
+            .find_map(|(root, data)| data.contains(path).map(|it| (root, it)))
     }
 }
 
-impl Deref for Roots {
-    type Target = Arena<VfsRoot, Arc<RootFilter>>;
-    fn deref(&self) -> &Self::Target {
-        &self.roots
-    }
-}
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct VfsFile(pub RawId);
+impl_arena_id!(VfsFile);
 
-impl DerefMut for Roots {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        &mut self.roots
-    }
+struct VfsFileData {
+    root: VfsRoot,
+    path: RelativePathBuf,
+    is_overlayed: bool,
+    text: Arc<String>,
 }
 
 pub struct Vfs {
     roots: Arc<Roots>,
     files: Arena<VfsFile, VfsFileData>,
-    root2files: FxHashMap<VfsRoot, FxHashSet<VfsFile>>,
+    root2files: ArenaMap<VfsRoot, FxHashSet<VfsFile>>,
     pending_changes: Vec<VfsChange>,
     worker: Worker,
 }
 
 impl fmt::Debug for Vfs {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.write_str("Vfs { ... }")
+        f.debug_struct("Vfs")
+            .field("n_roots", &self.roots.len())
+            .field("n_files", &self.files.len())
+            .field("n_pending_changes", &self.pending_changes.len())
+            .finish()
     }
 }
 
 impl Vfs {
     pub fn new(roots: Vec<PathBuf>) -> (Vfs, Vec<VfsRoot>) {
         let roots = Arc::new(Roots::new(roots));
-        let worker = io::Worker::start(roots.clone());
-        let mut root2files = FxHashMap::default();
+        let worker = io::Worker::start(Arc::clone(&roots));
+        let mut root2files = ArenaMap::default();
 
-        for (root, filter) in roots.iter() {
+        for (root, config) in roots.iter() {
             root2files.insert(root, Default::default());
             worker
                 .sender()
                 .send(io::Task::AddRoot {
                     root,
-                    filter: filter.clone(),
+                    config: Arc::clone(config),
                 })
                 .unwrap();
         }
@@ -242,7 +228,7 @@ impl Vfs {
                 let mut cur_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[&root]
+                let exising = self.root2files[root]
                     .iter()
                     .map(|&file| (self.files[file].path.clone(), file))
                     .collect::<FxHashMap<_, _>>();
@@ -384,7 +370,7 @@ impl Vfs {
             is_overlayed,
         };
         let file = self.files.alloc(data);
-        self.root2files.get_mut(&root).unwrap().insert(file);
+        self.root2files.get_mut(root).unwrap().insert(file);
         file
     }
 
@@ -399,7 +385,7 @@ impl Vfs {
         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);
+        let removed = self.root2files.get_mut(root).unwrap().remove(&file);
         assert!(removed);
     }
 
@@ -410,7 +396,7 @@ impl Vfs {
     }
 
     fn find_file(&self, root: VfsRoot, path: &RelativePath) -> Option<VfsFile> {
-        self.root2files[&root]
+        self.root2files[root]
             .iter()
             .map(|&it| it)
             .find(|&file| self.files[file].path == path)