1 files changed, 102 insertions, 0 deletions

diff --git a/crates/ra_vfs/src/roots.rs b/crates/ra_vfs/src/roots.rs
new file mode 100644
index 000000000..564e12239
--- /dev/null
+++ b/crates/ra_vfs/src/roots.rs
@@ -0,0 +1,102 @@
+use std::{
+    sync::Arc,
+    path::{Path, PathBuf},
+};
+
+use relative_path::RelativePathBuf;
+use ra_arena::{impl_arena_id, Arena, RawId};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct VfsRoot(pub RawId);
+impl_arena_id!(VfsRoot);
+
+/// Describes the contents of a single source root.
+///
+/// `RootConfig` can be thought of as a glob pattern like `src/**.rs` which
+/// specifies the source root or as a function which takes a `PathBuf` and
+/// returns `true` iff path belongs to the source root
+pub(crate) struct RootConfig {
+    pub(crate) root: PathBuf,
+    // result of `root.canonicalize()` if that differs from `root`; `None` otherwise.
+    canonical_root: Option<PathBuf>,
+    excluded_dirs: Vec<PathBuf>,
+}
+
+pub(crate) struct Roots {
+    roots: Arena<VfsRoot, Arc<RootConfig>>,
+}
+
+impl std::ops::Deref for Roots {
+    type Target = Arena<VfsRoot, Arc<RootConfig>>;
+    fn deref(&self) -> &Self::Target {
+        &self.roots
+    }
+}
+
+impl RootConfig {
+    fn new(root: PathBuf, excluded_dirs: Vec<PathBuf>) -> RootConfig {
+        let mut canonical_root = root.canonicalize().ok();
+        if Some(&root) == canonical_root.as_ref() {
+            canonical_root = None;
+        }
+        RootConfig { root, canonical_root, excluded_dirs }
+    }
+    /// Checks if root contains a path and returns a root-relative path.
+    pub(crate) fn contains(&self, path: &Path) -> Option<RelativePathBuf> {
+        // First, check excluded dirs
+        if self.excluded_dirs.iter().any(|it| path.starts_with(it)) {
+            return None;
+        }
+        let rel_path = path
+            .strip_prefix(&self.root)
+            .or_else(|err_payload| {
+                self.canonical_root
+                    .as_ref()
+                    .map_or(Err(err_payload), |canonical_root| path.strip_prefix(canonical_root))
+            })
+            .ok()?;
+        let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+
+        // Ignore some common directories.
+        //
+        // FIXME: don't hard-code, specify at source-root creation time using
+        // gitignore
+        for (i, c) in rel_path.components().enumerate() {
+            if let relative_path::Component::Normal(c) = c {
+                if (i == 0 && c == "target") || c == ".git" || c == "node_modules" {
+                    return None;
+                }
+            }
+        }
+
+        if path.is_file() && rel_path.extension() != Some("rs") {
+            return None;
+        }
+
+        Some(rel_path)
+    }
+}
+
+impl Roots {
+    pub(crate) fn new(mut paths: Vec<PathBuf>) -> Roots {
+        let mut roots = Arena::default();
+        // A hack to make nesting work.
+        paths.sort_by_key(|it| std::cmp::Reverse(it.as_os_str().len()));
+        paths.dedup();
+        for (i, path) in paths.iter().enumerate() {
+            let nested_roots = paths[..i]
+                .iter()
+                .filter(|it| it.starts_with(path))
+                .map(|it| it.clone())
+                .collect::<Vec<_>>();
+
+            let config = Arc::new(RootConfig::new(path.clone(), nested_roots));
+
+            roots.alloc(config.clone());
+        }
+        Roots { roots }
+    }
+    pub(crate) fn find(&self, path: &Path) -> Option<(VfsRoot, RelativePathBuf)> {
+        self.roots.iter().find_map(|(root, data)| data.contains(path).map(|it| (root, it)))
+    }
+}