internal: prepare to track changes to mem_docs

crates/rust-analyzer/src/mem_docs.rs

@@ -0,0 +1,56 @@
+//! In-memory document information.
+
+use rustc_hash::FxHashMap;
+use vfs::VfsPath;
+
+/// Holds the set of in-memory documents.
+///
+/// For these document, there true contents is maintained by the client. It
+/// might be different from what's on disk.
+#[derive(Default, Clone)]
+pub(crate) struct MemDocs {
+    mem_docs: FxHashMap<VfsPath, DocumentData>,
+}
+
+impl MemDocs {
+    pub(crate) fn contains(&self, path: &VfsPath) -> bool {
+        self.mem_docs.contains_key(path)
+    }
+    pub(crate) fn insert(&mut self, path: VfsPath, data: DocumentData) -> Result<(), ()> {
+        match self.mem_docs.insert(path, data) {
+            Some(_) => Err(()),
+            None => Ok(()),
+        }
+    }
+    pub(crate) fn remove(&mut self, path: &VfsPath) -> Result<(), ()> {
+        match self.mem_docs.remove(path) {
+            Some(_) => Ok(()),
+            None => Err(()),
+        }
+    }
+    pub(crate) fn get(&self, path: &VfsPath) -> Option<&DocumentData> {
+        self.mem_docs.get(path)
+    }
+    pub(crate) fn get_mut(&mut self, path: &VfsPath) -> Option<&mut DocumentData> {
+        self.mem_docs.get_mut(path)
+    }
+
+    pub(crate) fn iter(&self) -> impl Iterator<Item = &VfsPath> {
+        self.mem_docs.keys()
+    }
+}
+
+/// Information about a document that the Language Client
+/// knows about.
+/// Its lifetime is driven by the textDocument/didOpen and textDocument/didClose
+/// client notifications.
+#[derive(Debug, Clone)]
+pub(crate) struct DocumentData {
+    pub(crate) version: i32,
+}
+
+impl DocumentData {
+    pub(crate) fn new(version: i32) -> Self {
+        DocumentData { version }
+    }
+}