2 files changed, 144 insertions, 0 deletions

diff --git a/crates/libanalysis/Cargo.toml b/crates/libanalysis/Cargo.toml
new file mode 100644
index 000000000..c773f4211
--- /dev/null
+++ b/crates/libanalysis/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "libanalysis"
+version = "0.1.0"
+authors = ["Aleksey Kladov <[email protected]>"]
+
+[dependencies]
+log = "0.4.2"
+failure = "0.1.2"
+parking_lot = "0.6.3"
+once_cell = "0.1.4"
+libsyntax2 = { path = "../libsyntax2" }
+libeditor = { path = "../libeditor" }
diff --git a/crates/libanalysis/src/lib.rs b/crates/libanalysis/src/lib.rs
new file mode 100644
index 000000000..6a946a0b0
--- /dev/null
+++ b/crates/libanalysis/src/lib.rs
@@ -0,0 +1,132 @@
+extern crate failure;
+extern crate parking_lot;
+#[macro_use]
+extern crate log;
+extern crate once_cell;
+extern crate libsyntax2;
+extern crate libeditor;
+
+use once_cell::sync::OnceCell;
+
+use std::{
+    fs,
+    sync::Arc,
+    collections::hash_map::HashMap,
+    path::{PathBuf, Path},
+};
+use parking_lot::RwLock;
+use libsyntax2::ast;
+use libeditor::LineIndex;
+
+pub type Result<T> = ::std::result::Result<T, ::failure::Error>;
+
+pub struct WorldState {
+    data: Arc<WorldData>
+}
+
+pub struct World {
+    data: Arc<WorldData>,
+}
+
+impl WorldState {
+    pub fn new() -> WorldState {
+        WorldState {
+            data: Arc::new(WorldData::default())
+        }
+    }
+
+    pub fn snapshot(&self) -> World {
+        World { data: self.data.clone() }
+    }
+
+    pub fn change_overlay(&mut self, path: PathBuf, text: Option<String>) {
+        let data = self.data_mut();
+        data.file_map.get_mut().remove(&path);
+        if let Some(text) = text {
+            data.mem_map.insert(path, Arc::new(text));
+        } else {
+            data.mem_map.remove(&path);
+        }
+    }
+
+    fn data_mut(&mut self) -> &mut WorldData {
+        if Arc::get_mut(&mut self.data).is_none() {
+            let file_map = self.data.file_map.read().clone();
+            self.data = Arc::new(WorldData {
+                mem_map: self.data.mem_map.clone(),
+                file_map: RwLock::new(file_map),
+            });
+        }
+        Arc::get_mut(&mut self.data).unwrap()
+    }
+}
+
+
+impl World {
+    pub fn file_syntax(&self, path: &Path) -> Result<ast::File> {
+        let data = self.file_data(path)?;
+        let syntax = data.syntax
+            .get_or_init(|| {
+                trace!("parsing: {}", path.display());
+                ast::File::parse(self.file_text(path, &data))
+            }).clone();
+        Ok(syntax)
+    }
+
+    pub fn file_line_index(&self, path: &Path) -> Result<LineIndex> {
+        let data = self.file_data(path)?;
+        let index = data.lines
+            .get_or_init(|| {
+                trace!("calc line index: {}", path.display());
+                LineIndex::new(self.file_text(path, &data))
+            });
+        Ok(index.clone())
+    }
+
+    fn file_text<'a>(&'a self, path: &Path, file_data: &'a FileData) -> &'a str {
+        match file_data.text.as_ref() {
+            Some(text) => text.as_str(),
+            None => self.data.mem_map[path].as_str()
+        }
+    }
+
+    fn file_data(&self, path: &Path) -> Result<Arc<FileData>> {
+        {
+            let guard = self.data.file_map.read();
+            if let Some(data) = guard.get(path) {
+                return Ok(data.clone());
+            }
+        }
+
+        let text = if self.data.mem_map.contains_key(path) {
+            None
+        } else {
+            trace!("loading file from disk: {}", path.display());
+            Some(fs::read_to_string(path)?)
+        };
+        let res = {
+            let mut guard = self.data.file_map.write();
+            guard.entry(path.to_owned())
+                .or_insert_with(|| Arc::new(FileData {
+                    text,
+                    syntax: OnceCell::new(),
+                    lines: OnceCell::new(),
+                }))
+                .clone()
+        };
+        Ok(res)
+    }
+}
+
+
+#[derive(Default)]
+struct WorldData {
+    mem_map: HashMap<PathBuf, Arc<String>>,
+    file_map: RwLock<HashMap<PathBuf, Arc<FileData>>>,
+}
+
+struct FileData {
+    text: Option<String>,
+    syntax: OnceCell<ast::File>,
+    lines: OnceCell<LineIndex>,
+}