Adjust relative paths to the sysroot rather than rustup's home

Author: Xanewok

rls/src/actions/hover.rs

@@ -504,43 +504,6 @@ fn create_tooltip(
     tooltip
 }
 
-/// Skips `skip_components` from the `path` if the path starts with `prefix`.
-/// Returns the original path if there is no match.
-///
-/// # Examples
-///
-/// ```ignore
-/// # use std::path::Path;
-///
-/// let base_path = Path::new(".rustup/toolchains/nightly-x86_64-pc-windows-msvc/lib/rustlib/src/rust/src/liballoc/string.rs");
-/// let tidy_path = skip_path_components(base_path, ".rustup", 7);
-/// assert_eq!(tidy_path, Some(PathBuf::from("liballoc/string.rs")));
-///
-/// let base_path = Path::new("/home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/smallvec-0.6.2/lib.rs");
-/// let tidy_path = skip_path_components(base_path, "/home/user/.cargo", 3);
-/// assert_eq!(tidy_path, Some(PathBuf::from("smallvec-0.6.2/lib.rs")));
-///
-/// let base_path = Path::new("/home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/smallvec-0.6.2/lib.rs");
-/// let tidy_path = skip_path_components(base_path, ".cargo", 3);
-/// assert_eq!(tidy_path, None);
-///
-/// let base_path = Path::new("some/unknown/path/lib.rs");
-/// let tidy_path = skip_path_components(base_path, ".rustup", 4);
-/// assert_eq!(tidy_path, None);
-/// ```
-fn skip_path_components<P: AsRef<Path>>(
-    path: &Path,
-    prefix: P,
-    skip_components: usize,
-) -> Option<PathBuf> {
-    path.strip_prefix(prefix).ok().map(|stripped| {
-        stripped.components().skip(skip_components).fold(PathBuf::new(), |mut comps, comp| {
-            comps.push(comp);
-            comps
-        })
-    })
-}
-
 /// Collapses parent directory references inside of paths.
 ///
 /// # Example
@@ -613,20 +576,22 @@ fn racer_match_to_def(ctx: &InitActionContext, m: &racer::Match) -> Option<Def>
         use std::env;
 
         let home = home::home_dir().unwrap_or_default();
-        let rustup_home =
-            env::var("RUSTUP_HOME").map(PathBuf::from).unwrap_or_else(|_| home.join(".rustup"));
         let cargo_home =
             env::var("CARGO_HOME").map(PathBuf::from).unwrap_or_else(|_| home.join(".cargo"));
+        let cargo_registry_src = cargo_home.join("registry").join("src").join("github.com-1ecc6299db9ec823");
+        let rust_src_path = racer::get_rust_src_path().ok();
 
         let contextstr = m.contextstr.replacen("\\\\?\\", "", 1);
         let contextstr_path = PathBuf::from(&contextstr);
         let contextstr_path = collapse_parents(contextstr_path);
 
+
         // Tidy up the module path.
-        // Skips `toolchains/$TOOLCHAIN/lib/rustlib/src/rust/src`.
-        skip_path_components(&contextstr_path, rustup_home, 7)
-            // Skips `/registry/src/github.com-1ecc6299db9ec823/`.
-            .or_else(|| skip_path_components(&contextstr_path, cargo_home, 3))
+        // Try to display the path relative to libstd src root if possible.
+        rust_src_path
+            .and_then(|path| contextstr_path.strip_prefix(path).ok().map(ToOwned::to_owned))
+            // Make the path relative to the package root cached in Cargo registry
+            .or_else(|| contextstr_path.strip_prefix(cargo_registry_src).ok().map(ToOwned::to_owned))
             // Make the path relative to the root of the project, if possible.
             .or_else(|| {
                 contextstr_path.strip_prefix(&ctx.current_project).ok().map(ToOwned::to_owned)