1 files changed, 132 insertions, 0 deletions

diff --git a/crates/ra_lsp_server/src/project_model/sysroot.rs b/crates/ra_lsp_server/src/project_model/sysroot.rs
new file mode 100644
index 000000000..1dbab57f8
--- /dev/null
+++ b/crates/ra_lsp_server/src/project_model/sysroot.rs
@@ -0,0 +1,132 @@
+use std::{
+    path::{Path, PathBuf},
+    process::Command,
+};
+
+use ra_syntax::SmolStr;
+use ra_arena::{Arena, RawId, impl_arena_id};
+
+use crate::Result;
+
+#[derive(Debug, Clone)]
+pub struct Sysroot {
+    crates: Arena<SysrootCrate, SysrootCrateData>,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct SysrootCrate(RawId);
+impl_arena_id!(SysrootCrate);
+
+#[derive(Debug, Clone)]
+struct SysrootCrateData {
+    name: SmolStr,
+    root: PathBuf,
+    deps: Vec<SysrootCrate>,
+}
+
+impl Sysroot {
+    pub(crate) fn std(&self) -> Option<SysrootCrate> {
+        self.by_name("std")
+    }
+
+    pub(crate) fn crates<'a>(&'a self) -> impl Iterator<Item = SysrootCrate> + 'a {
+        self.crates.iter().map(|(id, _data)| id)
+    }
+
+    pub(super) fn discover(cargo_toml: &Path) -> Result<Sysroot> {
+        let rustc_output = Command::new("rustc")
+            .current_dir(cargo_toml.parent().unwrap())
+            .args(&["--print", "sysroot"])
+            .output()?;
+        if !rustc_output.status.success() {
+            failure::bail!("failed to locate sysroot")
+        }
+        let stdout = String::from_utf8(rustc_output.stdout)?;
+        let sysroot_path = Path::new(stdout.trim());
+        let src = sysroot_path.join("lib/rustlib/src/rust/src");
+
+        let mut sysroot = Sysroot {
+            crates: Arena::default(),
+        };
+        for name in SYSROOT_CRATES.trim().lines() {
+            let root = src.join(format!("lib{}", name)).join("lib.rs");
+            if root.exists() {
+                sysroot.crates.alloc(SysrootCrateData {
+                    name: name.into(),
+                    root,
+                    deps: Vec::new(),
+                });
+            }
+        }
+        if let Some(std) = sysroot.std() {
+            for dep in STD_DEPS.trim().lines() {
+                if let Some(dep) = sysroot.by_name(dep) {
+                    sysroot.crates[std].deps.push(dep)
+                }
+            }
+        }
+        Ok(sysroot)
+    }
+
+    fn by_name(&self, name: &str) -> Option<SysrootCrate> {
+        self.crates
+            .iter()
+            .find(|(_id, data)| data.name == name)
+            .map(|(id, _data)| id)
+    }
+}
+
+impl SysrootCrate {
+    pub(crate) fn name(self, sysroot: &Sysroot) -> &SmolStr {
+        &sysroot.crates[self].name
+    }
+    pub(crate) fn root(self, sysroot: &Sysroot) -> &Path {
+        sysroot.crates[self].root.as_path()
+    }
+    pub(crate) fn root_dir(self, sysroot: &Sysroot) -> &Path {
+        self.root(sysroot).parent().unwrap()
+    }
+    pub(crate) fn deps<'a>(self, sysroot: &'a Sysroot) -> impl Iterator<Item = SysrootCrate> + 'a {
+        sysroot.crates[self].deps.iter().map(|&it| it)
+    }
+}
+
+const SYSROOT_CRATES: &str = "
+std
+core
+alloc
+collections
+libc
+panic_unwind
+proc_macro
+rustc_unicode
+std_unicode
+test
+alloc_jemalloc
+alloc_system
+compiler_builtins
+getopts
+panic_unwind
+panic_abort
+rand
+term
+unwind
+build_helper
+rustc_asan
+rustc_lsan
+rustc_msan
+rustc_tsan
+syntax";
+
+const STD_DEPS: &str = "
+alloc_jemalloc
+alloc_system
+panic_abort
+rand
+compiler_builtins
+unwind
+rustc_asan
+rustc_lsan
+rustc_msan
+rustc_tsan
+build_helper";