1 files changed, 50 insertions, 1 deletions

diff --git a/crates/vfs/src/vfs_path.rs b/crates/vfs/src/vfs_path.rs
index de5dc0bf3..0a8a86c62 100644
--- a/crates/vfs/src/vfs_path.rs
+++ b/crates/vfs/src/vfs_path.rs
@@ -9,9 +9,17 @@ use paths::{AbsPath, AbsPathBuf};
 pub struct VfsPath(VfsPathRepr);
 
 impl VfsPath {
+    /// Creates an "in-memory" path from `/`-separates string.
+    /// This is most useful for testing, to avoid windows/linux differences
+    pub fn new_virtual_path(path: String) -> VfsPath {
+        assert!(path.starts_with('/'));
+        VfsPath(VfsPathRepr::VirtualPath(VirtualPath(path)))
+    }
+
     pub fn as_path(&self) -> Option<&AbsPath> {
         match &self.0 {
             VfsPathRepr::PathBuf(it) => Some(it.as_path()),
+            VfsPathRepr::VirtualPath(_) => None,
         }
     }
     pub fn join(&self, path: &str) -> VfsPath {
@@ -20,11 +28,24 @@ impl VfsPath {
                 let res = it.join(path).normalize();
                 VfsPath(VfsPathRepr::PathBuf(res))
             }
+            VfsPathRepr::VirtualPath(it) => {
+                let res = it.join(path);
+                VfsPath(VfsPathRepr::VirtualPath(res))
+            }
         }
     }
     pub fn pop(&mut self) -> bool {
         match &mut self.0 {
             VfsPathRepr::PathBuf(it) => it.pop(),
+            VfsPathRepr::VirtualPath(it) => it.pop(),
+        }
+    }
+    pub fn starts_with(&self, other: &VfsPath) -> bool {
+        match (&self.0, &other.0) {
+            (VfsPathRepr::PathBuf(lhs), VfsPathRepr::PathBuf(rhs)) => lhs.starts_with(rhs),
+            (VfsPathRepr::PathBuf(_), _) => false,
+            (VfsPathRepr::VirtualPath(lhs), VfsPathRepr::VirtualPath(rhs)) => lhs.starts_with(rhs),
+            (VfsPathRepr::VirtualPath(_), _) => false,
         }
     }
 }
@@ -32,11 +53,12 @@ impl VfsPath {
 #[derive(Debug, Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]
 enum VfsPathRepr {
     PathBuf(AbsPathBuf),
+    VirtualPath(VirtualPath),
 }
 
 impl From<AbsPathBuf> for VfsPath {
     fn from(v: AbsPathBuf) -> Self {
-        VfsPath(VfsPathRepr::PathBuf(v))
+        VfsPath(VfsPathRepr::PathBuf(v.normalize()))
     }
 }
 
@@ -44,6 +66,33 @@ impl fmt::Display for VfsPath {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match &self.0 {
             VfsPathRepr::PathBuf(it) => fmt::Display::fmt(&it.display(), f),
+            VfsPathRepr::VirtualPath(VirtualPath(it)) => fmt::Display::fmt(it, f),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]
+struct VirtualPath(String);
+
+impl VirtualPath {
+    fn starts_with(&self, other: &VirtualPath) -> bool {
+        self.0.starts_with(&other.0)
+    }
+    fn pop(&mut self) -> bool {
+        let pos = match self.0.rfind('/') {
+            Some(pos) => pos,
+            None => return false,
+        };
+        self.0 = self.0[..pos].to_string();
+        true
+    }
+    fn join(&self, mut path: &str) -> VirtualPath {
+        let mut res = self.clone();
+        while path.starts_with("../") {
+            assert!(res.pop());
+            path = &path["../".len()..]
         }
+        res.0 = format!("{}/{}", res.0, path);
+        res
     }
 }