4 files changed, 259 insertions, 0 deletions

diff --git a/crates/ra_vfs/Cargo.toml b/crates/ra_vfs/Cargo.toml
new file mode 100644
index 000000000..f8d49b3f5
--- /dev/null
+++ b/crates/ra_vfs/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+edition = "2018"
+name = "ra_vfs"
+version = "0.1.0"
+authors = ["Aleksey Kladov <[email protected]>"]
+
+[dependencies]
+walkdir = "2.2.7"
+relative-path = "0.4.0"
+rustc-hash = "1.0"
+crossbeam-channel = "0.2.4"
diff --git a/crates/ra_vfs/src/arena.rs b/crates/ra_vfs/src/arena.rs
new file mode 100644
index 000000000..d6fad753b
--- /dev/null
+++ b/crates/ra_vfs/src/arena.rs
@@ -0,0 +1,48 @@
+use std::{
+    hash::{Hash, Hasher},
+    marker::PhantomData,
+    ops::{Index, IndexMut},
+};
+
+#[derive(Clone, Debug)]
+pub(crate) struct Arena<ID: ArenaId, T> {
+    data: Vec<T>,
+    _ty: PhantomData<ID>,
+}
+
+pub(crate) trait ArenaId {
+    fn from_u32(id: u32) -> Self;
+    fn to_u32(self) -> u32;
+}
+
+impl<ID: ArenaId, T> Arena<ID, T> {
+    pub fn alloc(&mut self, value: T) -> ID {
+        let id = self.data.len() as u32;
+        self.data.push(value);
+        ID::from_u32(id)
+    }
+}
+
+impl<ID: ArenaId, T> Default for Arena<ID, T> {
+    fn default() -> Arena<ID, T> {
+        Arena {
+            data: Vec::new(),
+            _ty: PhantomData,
+        }
+    }
+}
+
+impl<ID: ArenaId, T> Index<ID> for Arena<ID, T> {
+    type Output = T;
+    fn index(&self, idx: ID) -> &T {
+        let idx = idx.to_u32() as usize;
+        &self.data[idx]
+    }
+}
+
+impl<ID: ArenaId, T> IndexMut<ID> for Arena<ID, T> {
+    fn index_mut(&mut self, idx: ID) -> &mut T {
+        let idx = idx.to_u32() as usize;
+        &mut self.data[idx]
+    }
+}
diff --git a/crates/ra_vfs/src/io.rs b/crates/ra_vfs/src/io.rs
new file mode 100644
index 000000000..f90fe0e84
--- /dev/null
+++ b/crates/ra_vfs/src/io.rs
@@ -0,0 +1,72 @@
+use std::{
+    fs,
+    path::{Path, PathBuf},
+    thread::JoinHandle,
+};
+
+use walkdir::WalkDir;
+use crossbeam_channel::{Sender, Receiver};
+
+pub(crate) fn start_io() -> (JoinHandle<(), Sender<()>, Receiver()>) {}
+
+// use crate::thread_watcher::{ThreadWatcher, Worker};
+
+// #[derive(Debug)]
+// pub struct FileEvent {
+//     pub path: PathBuf,
+//     pub kind: FileEventKind,
+// }
+
+// #[derive(Debug)]
+// pub enum FileEventKind {
+//     Add(String),
+// }
+
+// pub fn roots_loader() -> (Worker<PathBuf, (PathBuf, Vec<FileEvent>)>, ThreadWatcher) {
+//     Worker::<PathBuf, (PathBuf, Vec<FileEvent>)>::spawn(
+//         "roots loader",
+//         128,
+//         |input_receiver, output_sender| {
+//             input_receiver
+//                 .map(|path| {
+//                     log::debug!("loading {} ...", path.as_path().display());
+//                     let events = load_root(path.as_path());
+//                     log::debug!("... loaded {}", path.as_path().display());
+//                     (path, events)
+//                 })
+//                 .for_each(|it| output_sender.send(it))
+//         },
+//     )
+// }
+
+// fn load_root(path: &Path) -> Vec<FileEvent> {
+//     let mut res = Vec::new();
+//     for entry in WalkDir::new(path) {
+//         let entry = match entry {
+//             Ok(entry) => entry,
+//             Err(e) => {
+//                 log::warn!("watcher error: {}", e);
+//                 continue;
+//             }
+//         };
+//         if !entry.file_type().is_file() {
+//             continue;
+//         }
+//         let path = entry.path();
+//         if path.extension().and_then(|os| os.to_str()) != Some("rs") {
+//             continue;
+//         }
+//         let text = match fs::read_to_string(path) {
+//             Ok(text) => text,
+//             Err(e) => {
+//                 log::warn!("watcher error: {}", e);
+//                 continue;
+//             }
+//         };
+//         res.push(FileEvent {
+//             path: path.to_owned(),
+//             kind: FileEventKind::Add(text),
+//         })
+//     }
+//     res
+// }
diff --git a/crates/ra_vfs/src/lib.rs b/crates/ra_vfs/src/lib.rs
new file mode 100644
index 000000000..8f6abadb7
--- /dev/null
+++ b/crates/ra_vfs/src/lib.rs
@@ -0,0 +1,128 @@
+//! 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 also is responsible for watching the disk for changes, and for merging
+//! editor state (modified, unsaved files) with disk state.
+//!
+//! VFS is based on a concept of roots: a set of directories on the file system
+//! whihc are watched for changes. Typically, there will be a root for each
+//! Cargo package.
+mod arena;
+mod io;
+
+use std::{
+    cmp::Reverse,
+    path::{Path, PathBuf},
+    ffi::OsStr,
+    sync::Arc,
+};
+
+use relative_path::RelativePathBuf;
+use crate::arena::{ArenaId, Arena};
+
+/// `RootFilter` is a predicate that checks if a file can belong to a root
+struct RootFilter {
+    root: PathBuf,
+    file_filter: fn(&Path) -> bool,
+}
+
+impl RootFilter {
+    fn new(root: PathBuf) -> RootFilter {
+        RootFilter {
+            root,
+            file_filter: rs_extension_filter,
+        }
+    }
+    fn can_contain(&self, path: &Path) -> bool {
+        (self.file_filter)(path) && path.starts_with(&self.root)
+    }
+}
+
+fn rs_extension_filter(p: &Path) -> bool {
+    p.extension() == Some(OsStr::new("rs"))
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
+pub struct VfsRoot(u32);
+
+impl ArenaId for VfsRoot {
+    fn from_u32(idx: u32) -> VfsRoot {
+        VfsRoot(idx)
+    }
+    fn to_u32(self) -> u32 {
+        self.0
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
+pub struct VfsFile(u32);
+
+impl ArenaId for VfsFile {
+    fn from_u32(idx: u32) -> VfsFile {
+        VfsFile(idx)
+    }
+    fn to_u32(self) -> u32 {
+        self.0
+    }
+}
+
+struct VfsFileData {
+    root: VfsRoot,
+    path: RelativePathBuf,
+    text: Arc<String>,
+}
+
+#[derive(Default)]
+struct Vfs {
+    roots: Arena<VfsRoot, RootFilter>,
+    files: Arena<VfsFile, VfsFileData>,
+    // pending_changes: Vec<PendingChange>,
+}
+
+impl Vfs {
+    pub fn new(mut roots: Vec<PathBuf>) -> Vfs {
+        let mut res = Vfs::default();
+
+        roots.sort_by_key(|it| Reverse(it.as_os_str().len()));
+
+        for path in roots {
+            res.roots.alloc(RootFilter::new(path));
+        }
+        res
+    }
+
+    pub fn add_file_overlay(&mut self, path: &Path, content: String) {}
+
+    pub fn change_file_overlay(&mut self, path: &Path, new_content: String) {}
+
+    pub fn remove_file_overlay(&mut self, path: &Path) {}
+
+    pub fn commit_changes(&mut self) -> Vec<VfsChange> {
+        unimplemented!()
+    }
+}
+
+#[derive(Debug, Clone)]
+pub enum VfsChange {
+    AddRoot {
+        root: VfsRoot,
+        files: Vec<(VfsFile, RelativePathBuf, Arc<String>)>,
+    },
+    AddFile {
+        file: VfsFile,
+        root: VfsRoot,
+        path: RelativePathBuf,
+        text: Arc<String>,
+    },
+    RemoveFile {
+        file: VfsFile,
+    },
+    ChangeFile {
+        file: VfsFile,
+        text: Arc<String>,
+    },
+}