VFS no longer stores all source files in memory

9 files changed, 130 insertions, 143 deletions

diff --git a/crates/load-cargo/src/lib.rs b/crates/load-cargo/src/lib.rs
index 556ed73a04c..ee0b9e6d504 100644
--- a/crates/load-cargo/src/lib.rs
+++ b/crates/load-cargo/src/lib.rs
@@ -331,9 +331,8 @@ fn load_crate_graph(
     }
     let changes = vfs.take_changes();
     for file in changes {
-        if file.exists() {
-            let contents = vfs.file_contents(file.file_id);
-            if let Ok(text) = std::str::from_utf8(contents) {
+        if let vfs::Change::Create(v) | vfs::Change::Modify(v) = file.change {
+            if let Ok(text) = std::str::from_utf8(&v) {
                 analysis_change.change_file(file.file_id, Some(text.into()))
             }
         }
diff --git a/crates/rust-analyzer/src/global_state.rs b/crates/rust-analyzer/src/global_state.rs
index f57a27305f0..da132f93968 100644
--- a/crates/rust-analyzer/src/global_state.rs
+++ b/crates/rust-analyzer/src/global_state.rs
@@ -3,7 +3,7 @@
 //!
 //! Each tick provides an immutable snapshot of the state as `WorldSnapshot`.
 
-use std::time::Instant;
+use std::{collections::hash_map::Entry, time::Instant};
 
 use crossbeam_channel::{unbounded, Receiver, Sender};
 use flycheck::FlycheckHandle;
@@ -21,7 +21,7 @@ use proc_macro_api::ProcMacroServer;
 use project_model::{CargoWorkspace, ProjectWorkspace, Target, WorkspaceBuildScripts};
 use rustc_hash::{FxHashMap, FxHashSet};
 use triomphe::Arc;
-use vfs::{AnchoredPathBuf, Vfs};
+use vfs::{AnchoredPathBuf, ChangedFile, Vfs};
 
 use crate::{
     config::{Config, ConfigError},
@@ -217,8 +217,8 @@ impl GlobalState {
     pub(crate) fn process_changes(&mut self) -> bool {
         let _p = profile::span("GlobalState::process_changes");
 
-        let mut file_changes = FxHashMap::default();
-        let (change, changed_files, workspace_structure_change) = {
+        let mut file_changes = FxHashMap::<_, (bool, ChangedFile)>::default();
+        let (change, modified_files, workspace_structure_change) = {
             let mut change = Change::new();
             let mut guard = self.vfs.write();
             let changed_files = guard.0.take_changes();
@@ -233,64 +233,63 @@ impl GlobalState {
             // id that is followed by a delete we actually skip observing the file text from the
             // earlier event, to avoid problems later on.
             for changed_file in changed_files {
-                use vfs::ChangeKind::*;
-
-                file_changes
-                    .entry(changed_file.file_id)
-                    .and_modify(|(change, just_created)| {
-                        // None -> Delete => keep
-                        // Create -> Delete => collapse
-                        //
-                        match (change, just_created, changed_file.change_kind) {
+                use vfs::Change::*;
+                match file_changes.entry(changed_file.file_id) {
+                    Entry::Occupied(mut o) => {
+                        let (just_created, change) = o.get_mut();
+                        match (&mut change.change, just_created, changed_file.change) {
                             // latter `Delete` wins
                             (change, _, Delete) => *change = Delete,
                             // merge `Create` with `Create` or `Modify`
-                            (Create, _, Create | Modify) => {}
+                            (Create(prev), _, Create(new) | Modify(new)) => *prev = new,
                             // collapse identical `Modify`es
-                            (Modify, _, Modify) => {}
+                            (Modify(prev), _, Modify(new)) => *prev = new,
                             // equivalent to `Modify`
-                            (change @ Delete, just_created, Create) => {
-                                *change = Modify;
+                            (change @ Delete, just_created, Create(new)) => {
+                                *change = Modify(new);
                                 *just_created = true;
                             }
                             // shouldn't occur, but collapse into `Create`
-                            (change @ Delete, just_created, Modify) => {
-                                *change = Create;
+                            (change @ Delete, just_created, Modify(new)) => {
+                                *change = Create(new);
                                 *just_created = true;
                             }
                             // shouldn't occur, but collapse into `Modify`
-                            (Modify, _, Create) => {}
+                            (Modify(prev), _, Create(new)) => *prev = new,
                         }
-                    })
-                    .or_insert((
-                        changed_file.change_kind,
-                        matches!(changed_file.change_kind, Create),
-                    ));
+                    }
+                    Entry::Vacant(v) => {
+                        _ = v.insert((matches!(&changed_file.change, Create(_)), changed_file))
+                    }
+                }
             }
 
             let changed_files: Vec<_> = file_changes
                 .into_iter()
-                .filter(|(_, (change_kind, just_created))| {
-                    !matches!((change_kind, just_created), (vfs::ChangeKind::Delete, true))
+                .filter(|(_, (just_created, change))| {
+                    !(*just_created && matches!(change.change, vfs::Change::Delete))
                 })
-                .map(|(file_id, (change_kind, _))| vfs::ChangedFile { file_id, change_kind })
+                .map(|(file_id, (_, change))| vfs::ChangedFile { file_id, ..change })
                 .collect();
 
             let mut workspace_structure_change = None;
             // A file was added or deleted
             let mut has_structure_changes = false;
             let mut bytes = vec![];
-            for file in &changed_files {
+            let mut modified_files = vec![];
+            for file in changed_files {
                 let vfs_path = &vfs.file_path(file.file_id);
                 if let Some(path) = vfs_path.as_path() {
                     let path = path.to_path_buf();
-                    if reload::should_refresh_for_change(&path, file.change_kind) {
+                    if reload::should_refresh_for_change(&path, file.kind()) {
                         workspace_structure_change = Some((path.clone(), false));
                     }
                     if file.is_created_or_deleted() {
                         has_structure_changes = true;
                         workspace_structure_change =
                             Some((path, self.crate_graph_file_dependencies.contains(vfs_path)));
+                    } else {
+                        modified_files.push(file.file_id);
                     }
                 }
 
@@ -299,10 +298,8 @@ impl GlobalState {
                     self.diagnostics.clear_native_for(file.file_id);
                 }
 
-                let text = if file.exists() {
-                    let bytes = vfs.file_contents(file.file_id).to_vec();
-
-                    String::from_utf8(bytes).ok().and_then(|text| {
+                let text = if let vfs::Change::Create(v) | vfs::Change::Modify(v) = file.change {
+                    String::from_utf8(v).ok().and_then(|text| {
                         // FIXME: Consider doing normalization in the `vfs` instead? That allows
                         // getting rid of some locking
                         let (text, line_endings) = LineEndings::normalize(text);
@@ -327,11 +324,10 @@ impl GlobalState {
                 let roots = self.source_root_config.partition(vfs);
                 change.set_roots(roots);
             }
-            (change, changed_files, workspace_structure_change)
+            (change, modified_files, workspace_structure_change)
         };
 
         self.analysis_host.apply_change(change);
-
         {
             let raw_database = self.analysis_host.raw_database();
             // FIXME: ideally we should only trigger a workspace fetch for non-library changes
@@ -343,13 +339,12 @@ impl GlobalState {
                     force_crate_graph_reload,
                 );
             }
-            self.proc_macro_changed =
-                changed_files.iter().filter(|file| !file.is_created_or_deleted()).any(|file| {
-                    let crates = raw_database.relevant_crates(file.file_id);
-                    let crate_graph = raw_database.crate_graph();
+            self.proc_macro_changed = modified_files.into_iter().any(|file_id| {
+                let crates = raw_database.relevant_crates(file_id);
+                let crate_graph = raw_database.crate_graph();
 
-                    crates.iter().any(|&krate| crate_graph[krate].is_proc_macro)
-                });
+                crates.iter().any(|&krate| crate_graph[krate].is_proc_macro)
+            });
         }
 
         true
@@ -494,10 +489,6 @@ impl GlobalStateSnapshot {
         })
     }
 
-    pub(crate) fn vfs_memory_usage(&self) -> usize {
-        self.vfs_read().memory_usage()
-    }
-
     pub(crate) fn file_exists(&self, file_id: FileId) -> bool {
         self.vfs.read().0.exists(file_id)
     }
diff --git a/crates/rust-analyzer/src/handlers/notification.rs b/crates/rust-analyzer/src/handlers/notification.rs
index 7e6219991b6..c0d35498c66 100644
--- a/crates/rust-analyzer/src/handlers/notification.rs
+++ b/crates/rust-analyzer/src/handlers/notification.rs
@@ -59,7 +59,13 @@ pub(crate) fn handle_did_open_text_document(
     if let Ok(path) = from_proto::vfs_path(&params.text_document.uri) {
         let already_exists = state
             .mem_docs
-            .insert(path.clone(), DocumentData::new(params.text_document.version))
+            .insert(
+                path.clone(),
+                DocumentData::new(
+                    params.text_document.version,
+                    params.text_document.text.clone().into_bytes(),
+                ),
+            )
             .is_err();
         if already_exists {
             tracing::error!("duplicate DidOpenTextDocument: {}", path);
@@ -76,11 +82,12 @@ pub(crate) fn handle_did_change_text_document(
     let _p = profile::span("handle_did_change_text_document");
 
     if let Ok(path) = from_proto::vfs_path(&params.text_document.uri) {
-        match state.mem_docs.get_mut(&path) {
+        let data = match state.mem_docs.get_mut(&path) {
             Some(doc) => {
                 // The version passed in DidChangeTextDocument is the version after all edits are applied
                 // so we should apply it before the vfs is notified.
                 doc.version = params.text_document.version;
+                &mut doc.data
             }
             None => {
                 tracing::error!("unexpected DidChangeTextDocument: {}", path);
@@ -88,16 +95,14 @@ pub(crate) fn handle_did_change_text_document(
             }
         };
 
-        let text = apply_document_changes(
+        let new_contents = apply_document_changes(
             state.config.position_encoding(),
-            || {
-                let vfs = &state.vfs.read().0;
-                let file_id = vfs.file_id(&path).unwrap();
-                std::str::from_utf8(vfs.file_contents(file_id)).unwrap().into()
-            },
+            std::str::from_utf8(data).unwrap(),
             params.content_changes,
-        );
-        state.vfs.write().0.set_file_contents(path, Some(text.into_bytes()));
+        )
+        .into_bytes();
+        *data = new_contents.clone();
+        state.vfs.write().0.set_file_contents(path, Some(new_contents));
     }
     Ok(())
 }
diff --git a/crates/rust-analyzer/src/handlers/request.rs b/crates/rust-analyzer/src/handlers/request.rs
index 13544558c50..22c7e9b0503 100644
--- a/crates/rust-analyzer/src/handlers/request.rs
+++ b/crates/rust-analyzer/src/handlers/request.rs
@@ -103,7 +103,6 @@ pub(crate) fn handle_analyzer_status(
                 .collect::<Vec<&AbsPath>>()
         );
     }
-    format_to!(buf, "\nVfs memory usage: {}\n", profile::Bytes::new(snap.vfs_memory_usage() as _));
     buf.push_str("\nAnalysis:\n");
     buf.push_str(
         &snap
diff --git a/crates/rust-analyzer/src/lsp/utils.rs b/crates/rust-analyzer/src/lsp/utils.rs
index a4417e4d4a1..fa5ea5b57db 100644
--- a/crates/rust-analyzer/src/lsp/utils.rs
+++ b/crates/rust-analyzer/src/lsp/utils.rs
@@ -168,7 +168,7 @@ impl GlobalState {
 
 pub(crate) fn apply_document_changes(
     encoding: PositionEncoding,
-    file_contents: impl FnOnce() -> String,
+    file_contents: &str,
     mut content_changes: Vec<lsp_types::TextDocumentContentChangeEvent>,
 ) -> String {
     // If at least one of the changes is a full document change, use the last
@@ -179,7 +179,7 @@ pub(crate) fn apply_document_changes(
                 let text = mem::take(&mut content_changes[idx].text);
                 (text, &content_changes[idx + 1..])
             }
-            None => (file_contents(), &content_changes[..]),
+            None => (file_contents.to_owned(), &content_changes[..]),
         };
     if content_changes.is_empty() {
         return text;
@@ -276,11 +276,11 @@ mod tests {
         }
 
         let encoding = PositionEncoding::Wide(WideEncoding::Utf16);
-        let text = apply_document_changes(encoding, || String::new(), vec![]);
+        let text = apply_document_changes(encoding, "", vec![]);
         assert_eq!(text, "");
         let text = apply_document_changes(
             encoding,
-            || text,
+            &text,
             vec![TextDocumentContentChangeEvent {
                 range: None,
                 range_length: None,
@@ -288,49 +288,46 @@ mod tests {
             }],
         );
         assert_eq!(text, "the");
-        let text = apply_document_changes(encoding, || text, c![0, 3; 0, 3 => " quick"]);
+        let text = apply_document_changes(encoding, &text, c![0, 3; 0, 3 => " quick"]);
         assert_eq!(text, "the quick");
         let text =
-            apply_document_changes(encoding, || text, c![0, 0; 0, 4 => "", 0, 5; 0, 5 => " foxes"]);
+            apply_document_changes(encoding, &text, c![0, 0; 0, 4 => "", 0, 5; 0, 5 => " foxes"]);
         assert_eq!(text, "quick foxes");
-        let text = apply_document_changes(encoding, || text, c![0, 11; 0, 11 => "\ndream"]);
+        let text = apply_document_changes(encoding, &text, c![0, 11; 0, 11 => "\ndream"]);
         assert_eq!(text, "quick foxes\ndream");
-        let text = apply_document_changes(encoding, || text, c![1, 0; 1, 0 => "have "]);
+        let text = apply_document_changes(encoding, &text, c![1, 0; 1, 0 => "have "]);
         assert_eq!(text, "quick foxes\nhave dream");
         let text = apply_document_changes(
             encoding,
-            || text,
+            &text,
             c![0, 0; 0, 0 => "the ", 1, 4; 1, 4 => " quiet", 1, 16; 1, 16 => "s\n"],
         );
         assert_eq!(text, "the quick foxes\nhave quiet dreams\n");
-        let text = apply_document_changes(
-            encoding,
-            || text,
-            c![0, 15; 0, 15 => "\n", 2, 17; 2, 17 => "\n"],
-        );
+        let text =
+            apply_document_changes(encoding, &text, c![0, 15; 0, 15 => "\n", 2, 17; 2, 17 => "\n"]);
         assert_eq!(text, "the quick foxes\n\nhave quiet dreams\n\n");
         let text = apply_document_changes(
             encoding,
-            || text,
+            &text,
             c![1, 0; 1, 0 => "DREAM", 2, 0; 2, 0 => "they ", 3, 0; 3, 0 => "DON'T THEY?"],
         );
         assert_eq!(text, "the quick foxes\nDREAM\nthey have quiet dreams\nDON'T THEY?\n");
         let text =
-            apply_document_changes(encoding, || text, c![0, 10; 1, 5 => "", 2, 0; 2, 12 => ""]);
+            apply_document_changes(encoding, &text, c![0, 10; 1, 5 => "", 2, 0; 2, 12 => ""]);
         assert_eq!(text, "the quick \nthey have quiet dreams\n");
 
         let text = String::from("❤️");
-        let text = apply_document_changes(encoding, || text, c![0, 0; 0, 0 => "a"]);
+        let text = apply_document_changes(encoding, &text, c![0, 0; 0, 0 => "a"]);
         assert_eq!(text, "a❤️");
 
         let text = String::from("a\nb");
         let text =
-            apply_document_changes(encoding, || text, c![0, 1; 1, 0 => "\nțc", 0, 1; 1, 1 => "d"]);
+            apply_document_changes(encoding, &text, c![0, 1; 1, 0 => "\nțc", 0, 1; 1, 1 => "d"]);
         assert_eq!(text, "adcb");
 
         let text = String::from("a\nb");
         let text =
-            apply_document_changes(encoding, || text, c![0, 1; 1, 0 => "ț\nc", 0, 2; 0, 2 => "c"]);
+            apply_document_changes(encoding, &text, c![0, 1; 1, 0 => "ț\nc", 0, 2; 0, 2 => "c"]);
         assert_eq!(text, "ațc\ncb");
     }
 
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index cdf41c955d2..356c332f90d 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -576,6 +576,8 @@ impl GlobalState {
                 let vfs = &mut self.vfs.write().0;
                 for (path, contents) in files {
                     let path = VfsPath::from(path);
+                    // if the file is in mem docs, it's managed by the client via notifications
+                    // so only set it if its not in there
                     if !self.mem_docs.contains(&path) {
                         vfs.set_file_contents(path, contents);
                     }
diff --git a/crates/rust-analyzer/src/mem_docs.rs b/crates/rust-analyzer/src/mem_docs.rs
index 45a1dab9772..6a93a0ebb4c 100644
--- a/crates/rust-analyzer/src/mem_docs.rs
+++ b/crates/rust-analyzer/src/mem_docs.rs
@@ -62,10 +62,11 @@ impl MemDocs {
 #[derive(Debug, Clone)]
 pub(crate) struct DocumentData {
     pub(crate) version: i32,
+    pub(crate) data: Vec<u8>,
 }
 
 impl DocumentData {
-    pub(crate) fn new(version: i32) -> Self {
-        DocumentData { version }
+    pub(crate) fn new(version: i32, data: Vec<u8>) -> Self {
+        DocumentData { version, data }
     }
 }
diff --git a/crates/rust-analyzer/src/reload.rs b/crates/rust-analyzer/src/reload.rs
index 91dc6c2e4b4..8e3fa7fa4da 100644
--- a/crates/rust-analyzer/src/reload.rs
+++ b/crates/rust-analyzer/src/reload.rs
@@ -503,10 +503,9 @@ impl GlobalState {
                 match vfs.file_id(&vfs_path) {
                     Some(file_id) => Some(file_id),
                     None => {
-                        if !self.mem_docs.contains(&vfs_path) {
-                            let contents = loader.handle.load_sync(path);
-                            vfs.set_file_contents(vfs_path.clone(), contents);
-                        }
+                        // FIXME: Consider not loading this here?
+                        let contents = loader.handle.load_sync(path);
+                        vfs.set_file_contents(vfs_path.clone(), contents);
                         vfs.file_id(&vfs_path)
                     }
                 }
diff --git a/crates/vfs/src/lib.rs b/crates/vfs/src/lib.rs
index ef5b10ee9db..34a85818eb8 100644
--- a/crates/vfs/src/lib.rs
+++ b/crates/vfs/src/lib.rs
@@ -1,8 +1,8 @@
 //! # Virtual File System
 //!
-//! VFS stores all files read by rust-analyzer. Reading file contents from VFS
-//! always returns the same contents, unless VFS was explicitly modified with
-//! [`set_file_contents`]. All changes to VFS are logged, and can be retrieved via
+//! VFS records all file changes pushed to it via [`set_file_contents`].
+//! As such it only ever stores changes, not the actual content of a file at any given moment.
+//! All file changes are logged, and can be retrieved via
 //! [`take_changes`] method. The pack of changes is then pushed to `salsa` and
 //! triggers incremental recomputation.
 //!
@@ -84,40 +84,65 @@ impl FileId {
 /// safe because `FileId` is a newtype of `u32`
 impl nohash_hasher::IsEnabled for FileId {}
 
-/// Storage for all files read by rust-analyzer.
+/// Storage for all file changes and the file id to path mapping.
 ///
 /// For more information see the [crate-level](crate) documentation.
 #[derive(Default)]
 pub struct Vfs {
     interner: PathInterner,
-    data: Vec<Option<Vec<u8>>>,
+    data: Vec<FileState>,
     changes: Vec<ChangedFile>,
 }
 
+#[derive(Copy, PartialEq, PartialOrd, Clone)]
+pub enum FileState {
+    Exists,
+    Deleted,
+}
+
 /// Changed file in the [`Vfs`].
 #[derive(Debug)]
 pub struct ChangedFile {
     /// Id of the changed file
     pub file_id: FileId,
     /// Kind of change
-    pub change_kind: ChangeKind,
+    pub change: Change,
 }
 
 impl ChangedFile {
     /// Returns `true` if the change is not [`Delete`](ChangeKind::Delete).
     pub fn exists(&self) -> bool {
-        self.change_kind != ChangeKind::Delete
+        !matches!(self.change, Change::Delete)
     }
 
     /// Returns `true` if the change is [`Create`](ChangeKind::Create) or
-    /// [`Delete`](ChangeKind::Delete).
+    /// [`Delete`](Change::Delete).
     pub fn is_created_or_deleted(&self) -> bool {
-        matches!(self.change_kind, ChangeKind::Create | ChangeKind::Delete)
+        matches!(self.change, Change::Create(_) | Change::Delete)
     }
+
+    pub fn kind(&self) -> ChangeKind {
+        match self.change {
+            Change::Create(_) => ChangeKind::Create,
+            Change::Modify(_) => ChangeKind::Modify,
+            Change::Delete => ChangeKind::Delete,
+        }
+    }
+}
+
+/// Kind of [file change](ChangedFile).
+#[derive(Eq, PartialEq, Debug)]
+pub enum Change {
+    /// The file was (re-)created
+    Create(Vec<u8>),
+    /// The file was modified
+    Modify(Vec<u8>),
+    /// The file was deleted
+    Delete,
 }
 
 /// Kind of [file change](ChangedFile).
-#[derive(Eq, PartialEq, Copy, Clone, Debug)]
+#[derive(Eq, PartialEq, Debug)]
 pub enum ChangeKind {
     /// The file was (re-)created
     Create,
@@ -130,7 +155,7 @@ pub enum ChangeKind {
 impl Vfs {
     /// Id of the given path if it exists in the `Vfs` and is not deleted.
     pub fn file_id(&self, path: &VfsPath) -> Option<FileId> {
-        self.interner.get(path).filter(|&it| self.get(it).is_some())
+        self.interner.get(path).filter(|&it| matches!(self.get(it), FileState::Exists))
     }
 
     /// File path corresponding to the given `file_id`.
@@ -142,28 +167,13 @@ impl Vfs {
         self.interner.lookup(file_id).clone()
     }
 
-    /// File content corresponding to the given `file_id`.
-    ///
-    /// # Panics
-    ///
-    /// Panics if the id is not present in the `Vfs`, or if the corresponding file is
-    /// deleted.
-    pub fn file_contents(&self, file_id: FileId) -> &[u8] {
-        self.get(file_id).as_deref().unwrap()
-    }
-
-    /// Returns the overall memory usage for the stored files.
-    pub fn memory_usage(&self) -> usize {
-        self.data.iter().flatten().map(|d| d.capacity()).sum()
-    }
-
     /// Returns an iterator over the stored ids and their corresponding paths.
     ///
     /// This will skip deleted files.
     pub fn iter(&self) -> impl Iterator<Item = (FileId, &VfsPath)> + '_ {
         (0..self.data.len())
             .map(|it| FileId(it as u32))
-            .filter(move |&file_id| self.get(file_id).is_some())
+            .filter(move |&file_id| matches!(self.get(file_id), FileState::Exists))
             .map(move |file_id| {
                 let path = self.interner.lookup(file_id);
                 (file_id, path)
@@ -176,28 +186,21 @@ impl Vfs {
     ///
     /// If the path does not currently exists in the `Vfs`, allocates a new
     /// [`FileId`] for it.
-    pub fn set_file_contents(&mut self, path: VfsPath, mut contents: Option<Vec<u8>>) -> bool {
+    pub fn set_file_contents(&mut self, path: VfsPath, contents: Option<Vec<u8>>) -> bool {
         let file_id = self.alloc_file_id(path);
-        let change_kind = match (self.get(file_id), &contents) {
-            (None, None) => return false,
-            (Some(old), Some(new)) if old == new => return false,
-            (None, Some(_)) => ChangeKind::Create,
-            (Some(_), None) => ChangeKind::Delete,
-            (Some(_), Some(_)) => ChangeKind::Modify,
+        let change_kind = match (self.get(file_id), contents) {
+            (FileState::Deleted, None) => return false,
+            (FileState::Deleted, Some(v)) => Change::Create(v),
+            (FileState::Exists, None) => Change::Delete,
+            (FileState::Exists, Some(v)) => Change::Modify(v),
         };
-        if let Some(contents) = &mut contents {
-            contents.shrink_to_fit();
-        }
-        *self.get_mut(file_id) = contents;
-        self.changes.push(ChangedFile { file_id, change_kind });
+        let changed_file = ChangedFile { file_id, change: change_kind };
+        self.data[file_id.0 as usize] =
+            if changed_file.exists() { FileState::Exists } else { FileState::Deleted };
+        self.changes.push(changed_file);
         true
     }
 
-    /// Returns `true` if the `Vfs` contains [changes](ChangedFile).
-    pub fn has_changes(&self) -> bool {
-        !self.changes.is_empty()
-    }
-
     /// Drain and returns all the changes in the `Vfs`.
     pub fn take_changes(&mut self) -> Vec<ChangedFile> {
         mem::take(&mut self.changes)
@@ -205,7 +208,7 @@ impl Vfs {
 
     /// Provides a panic-less way to verify file_id validity.
     pub fn exists(&self, file_id: FileId) -> bool {
-        self.get(file_id).is_some()
+        matches!(self.get(file_id), FileState::Exists)
     }
 
     /// Returns the id associated with `path`
@@ -219,26 +222,17 @@ impl Vfs {
         let file_id = self.interner.intern(path);
         let idx = file_id.0 as usize;
         let len = self.data.len().max(idx + 1);
-        self.data.resize_with(len, || None);
+        self.data.resize(len, FileState::Deleted);
         file_id
     }
 
-    /// Returns the content associated with the given `file_id`.
-    ///
-    /// # Panics
-    ///
-    /// Panics if no file is associated to that id.
-    fn get(&self, file_id: FileId) -> &Option<Vec<u8>> {
-        &self.data[file_id.0 as usize]
-    }
-
-    /// Mutably returns the content associated with the given `file_id`.
+    /// Returns the status of the file associated with the given `file_id`.
     ///
     /// # Panics
     ///
     /// Panics if no file is associated to that id.
-    fn get_mut(&mut self, file_id: FileId) -> &mut Option<Vec<u8>> {
-        &mut self.data[file_id.0 as usize]
+    fn get(&self, file_id: FileId) -> FileState {
+        self.data[file_id.0 as usize]
     }
 }