2 files changed, 116 insertions, 0 deletions

diff --git a/libanalysis/Cargo.toml b/libanalysis/Cargo.toml
new file mode 100644
index 000000000..bde5043e8
--- /dev/null
+++ b/libanalysis/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "libanalysis"
+version = "0.1.0"
+authors = ["Aleksey Kladov <[email protected]>"]
+
+[dependencies]
+failure = "0.1.2"
+parking_lot = "0.6.3"
+libsyntax2 = { path = "../" }
diff --git a/libanalysis/src/lib.rs b/libanalysis/src/lib.rs
new file mode 100644
index 000000000..07e7d567d
--- /dev/null
+++ b/libanalysis/src/lib.rs
@@ -0,0 +1,107 @@
+extern crate failure;
+extern crate libsyntax2;
+extern crate parking_lot;
+
+use std::{
+    fs,
+    sync::Arc,
+    collections::hash_map::HashMap,
+    path::{PathBuf, Path},
+};
+use parking_lot::RwLock;
+use libsyntax2::ast;
+
+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);
+        data.fs_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 fs_map = self.data.fs_map.read().clone();
+            let file_map = self.data.file_map.read().clone();
+            self.data = Arc::new(WorldData {
+                mem_map: self.data.mem_map.clone(),
+                fs_map: RwLock::new(fs_map),
+                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 guard = self.data.file_map.read();
+            if let Some(file) = guard.get(path) {
+                return Ok(file.clone());
+            }
+        }
+
+        let file = self.with_file_text(path, ast::File::parse)?;
+        let mut guard = self.data.file_map.write();
+        let file = guard.entry(path.to_owned())
+            .or_insert(file)
+            .clone();
+        Ok(file)
+    }
+
+    fn with_file_text<F: FnOnce(&str) -> R, R>(&self, path: &Path, f: F) -> Result<R> {
+        if let Some(text) = self.data.mem_map.get(path) {
+            return Ok(f(&*text));
+        }
+
+        {
+            let guard = self.data.fs_map.read();
+            if let Some(text) = guard.get(path) {
+                return Ok(f(&*text));
+            }
+        }
+
+        let text = fs::read_to_string(path)?;
+        {
+            let mut guard = self.data.fs_map.write();
+            guard.entry(path.to_owned())
+                .or_insert_with(|| Arc::new(text));
+        }
+        let guard = self.data.fs_map.read();
+        Ok(f(&guard[path]))
+    }
+}
+
+
+#[derive(Default)]
+struct WorldData {
+    mem_map: HashMap<PathBuf, Arc<String>>,
+    fs_map: RwLock<HashMap<PathBuf, Arc<String>>>,
+    file_map: RwLock<HashMap<PathBuf, ast::File>>,
+}