1 files changed, 113 insertions, 0 deletions

diff --git a/crates/libanalysis/src/roots.rs b/crates/libanalysis/src/roots.rs
new file mode 100644
index 000000000..675bce54c
--- /dev/null
+++ b/crates/libanalysis/src/roots.rs
@@ -0,0 +1,113 @@
+use std::{
+    collections::HashMap,
+    time::Instant,
+    sync::Arc,
+    panic,
+};
+
+use once_cell::sync::OnceCell;
+use rayon::prelude::*;
+use libeditor::LineIndex;
+use libsyntax2::File;
+
+use {
+    FileId,
+    module_map::{ModuleMap, ChangeKind},
+    symbol_index::FileSymbols,
+};
+
+#[derive(Clone, Default, Debug)]
+pub(crate) struct SourceRoot {
+    file_map: HashMap<FileId, Arc<FileData>>,
+    module_map: ModuleMap,
+}
+
+impl SourceRoot {
+    pub fn update(&mut self, file_id: FileId, text: Option<String>) {
+        let change_kind = if self.file_map.remove(&file_id).is_some() {
+            if text.is_some() {
+                ChangeKind::Update
+            } else {
+                ChangeKind::Delete
+            }
+        } else {
+            ChangeKind::Insert
+        };
+        self.module_map.update_file(file_id, change_kind);
+        self.file_map.remove(&file_id);
+        if let Some(text) = text {
+            let file_data = FileData::new(text);
+            self.file_map.insert(file_id, Arc::new(file_data));
+        } else {
+            self.file_map.remove(&file_id);
+        }
+    }
+    pub fn module_map(&self) -> &ModuleMap {
+        &self.module_map
+    }
+    pub fn lines(&self, file_id: FileId) -> &LineIndex {
+        let data = self.data(file_id);
+        data.lines.get_or_init(|| LineIndex::new(&data.text))
+    }
+    pub fn syntax(&self, file_id: FileId) -> &File {
+        let data = self.data(file_id);
+        let text = &data.text;
+        let syntax = &data.syntax;
+        match panic::catch_unwind(panic::AssertUnwindSafe(|| syntax.get_or_init(|| File::parse(text)))) {
+            Ok(file) => file,
+            Err(err) => {
+                error!("Parser paniced on:\n------\n{}\n------\n", &data.text);
+                panic::resume_unwind(err)
+            }
+        }
+    }
+    pub(crate) fn symbols(&self) -> Vec<(FileId, &FileSymbols)> {
+        self.file_map
+            .iter()
+            .map(|(&file_id, data)| (file_id, data.symbols()))
+            .collect()
+    }
+    pub fn reindex(&self) {
+        let now = Instant::now();
+        self.file_map
+            .par_iter()
+            .for_each(|(_, data)| {
+                data.symbols();
+            });
+        info!("parallel indexing took {:?}", now.elapsed());
+
+    }
+    fn data(&self, file_id: FileId) -> &FileData {
+        match self.file_map.get(&file_id) {
+            Some(data) => data,
+            None => panic!("unknown file: {:?}", file_id),
+        }
+    }
+}
+
+#[derive(Debug)]
+struct FileData {
+    text: String,
+    lines: OnceCell<LineIndex>,
+    syntax: OnceCell<File>,
+    symbols: OnceCell<FileSymbols>,
+}
+
+impl FileData {
+    fn new(text: String) -> FileData {
+        FileData {
+            text,
+            symbols: OnceCell::new(),
+            syntax: OnceCell::new(),
+            lines: OnceCell::new(),
+        }
+    }
+    fn syntax_transient(&self) -> File {
+        self.syntax.get().map(|s| s.clone())
+            .unwrap_or_else(|| File::parse(&self.text))
+    }
+    fn symbols(&self) -> &FileSymbols {
+        let syntax = self.syntax_transient();
+        self.symbols.get_or_init(|| FileSymbols::new(&syntax))
+    }
+}