1 files changed, 172 insertions, 0 deletions

diff --git a/crates/ra_project_model/src/cargo_workspace.rs b/crates/ra_project_model/src/cargo_workspace.rs
new file mode 100644
index 000000000..8adf463a6
--- /dev/null
+++ b/crates/ra_project_model/src/cargo_workspace.rs
@@ -0,0 +1,172 @@
+use std::path::{Path, PathBuf};
+
+use cargo_metadata::{MetadataCommand, CargoOpt};
+use ra_arena::{Arena, RawId, impl_arena_id};
+use rustc_hash::FxHashMap;
+use failure::format_err;
+
+use crate::Result;
+
+/// `CargoWorkspace` represents the logical structure of, well, a Cargo
+/// workspace. It pretty closely mirrors `cargo metadata` output.
+///
+/// Note that internally, rust analyzer uses a different structure:
+/// `CrateGraph`. `CrateGraph` is lower-level: it knows only about the crates,
+/// while this knows about `Pacakges` & `Targets`: purely cargo-related
+/// concepts.
+#[derive(Debug, Clone)]
+pub struct CargoWorkspace {
+    packages: Arena<Package, PackageData>,
+    targets: Arena<Target, TargetData>,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct Package(RawId);
+impl_arena_id!(Package);
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct Target(RawId);
+impl_arena_id!(Target);
+
+#[derive(Debug, Clone)]
+struct PackageData {
+    name: String,
+    manifest: PathBuf,
+    targets: Vec<Target>,
+    is_member: bool,
+    dependencies: Vec<PackageDependency>,
+}
+
+#[derive(Debug, Clone)]
+pub struct PackageDependency {
+    pub pkg: Package,
+    pub name: String,
+}
+
+#[derive(Debug, Clone)]
+struct TargetData {
+    pkg: Package,
+    name: String,
+    root: PathBuf,
+    kind: TargetKind,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum TargetKind {
+    Bin,
+    Lib,
+    Example,
+    Test,
+    Bench,
+    Other,
+}
+
+impl TargetKind {
+    fn new(kinds: &[String]) -> TargetKind {
+        for kind in kinds {
+            return match kind.as_str() {
+                "bin" => TargetKind::Bin,
+                "test" => TargetKind::Test,
+                "bench" => TargetKind::Bench,
+                "example" => TargetKind::Example,
+                _ if kind.contains("lib") => TargetKind::Lib,
+                _ => continue,
+            };
+        }
+        TargetKind::Other
+    }
+}
+
+impl Package {
+    pub fn name(self, ws: &CargoWorkspace) -> &str {
+        ws.packages[self].name.as_str()
+    }
+    pub fn root(self, ws: &CargoWorkspace) -> &Path {
+        ws.packages[self].manifest.parent().unwrap()
+    }
+    pub fn targets<'a>(self, ws: &'a CargoWorkspace) -> impl Iterator<Item = Target> + 'a {
+        ws.packages[self].targets.iter().cloned()
+    }
+    #[allow(unused)]
+    pub fn is_member(self, ws: &CargoWorkspace) -> bool {
+        ws.packages[self].is_member
+    }
+    pub fn dependencies<'a>(
+        self,
+        ws: &'a CargoWorkspace,
+    ) -> impl Iterator<Item = &'a PackageDependency> + 'a {
+        ws.packages[self].dependencies.iter()
+    }
+}
+
+impl Target {
+    pub fn package(self, ws: &CargoWorkspace) -> Package {
+        ws.targets[self].pkg
+    }
+    pub fn name(self, ws: &CargoWorkspace) -> &str {
+        ws.targets[self].name.as_str()
+    }
+    pub fn root(self, ws: &CargoWorkspace) -> &Path {
+        ws.targets[self].root.as_path()
+    }
+    pub fn kind(self, ws: &CargoWorkspace) -> TargetKind {
+        ws.targets[self].kind
+    }
+}
+
+impl CargoWorkspace {
+    pub fn from_cargo_metadata(cargo_toml: &Path) -> Result<CargoWorkspace> {
+        let mut meta = MetadataCommand::new();
+        meta.manifest_path(cargo_toml).features(CargoOpt::AllFeatures);
+        if let Some(parent) = cargo_toml.parent() {
+            meta.current_dir(parent);
+        }
+        let meta = meta.exec().map_err(|e| format_err!("cargo metadata failed: {}", e))?;
+        let mut pkg_by_id = FxHashMap::default();
+        let mut packages = Arena::default();
+        let mut targets = Arena::default();
+
+        let ws_members = &meta.workspace_members;
+
+        for meta_pkg in meta.packages {
+            let is_member = ws_members.contains(&meta_pkg.id);
+            let pkg = packages.alloc(PackageData {
+                name: meta_pkg.name.into(),
+                manifest: meta_pkg.manifest_path.clone(),
+                targets: Vec::new(),
+                is_member,
+                dependencies: Vec::new(),
+            });
+            let pkg_data = &mut packages[pkg];
+            pkg_by_id.insert(meta_pkg.id.clone(), pkg);
+            for meta_tgt in meta_pkg.targets {
+                let tgt = targets.alloc(TargetData {
+                    pkg,
+                    name: meta_tgt.name.into(),
+                    root: meta_tgt.src_path.clone(),
+                    kind: TargetKind::new(meta_tgt.kind.as_slice()),
+                });
+                pkg_data.targets.push(tgt);
+            }
+        }
+        let resolve = meta.resolve.expect("metadata executed with deps");
+        for node in resolve.nodes {
+            let source = pkg_by_id[&node.id];
+            for dep_node in node.deps {
+                let dep =
+                    PackageDependency { name: dep_node.name.into(), pkg: pkg_by_id[&dep_node.pkg] };
+                packages[source].dependencies.push(dep);
+            }
+        }
+
+        Ok(CargoWorkspace { packages, targets })
+    }
+
+    pub fn packages<'a>(&'a self) -> impl Iterator<Item = Package> + 'a {
+        self.packages.iter().map(|(id, _pkg)| id)
+    }
+
+    pub fn target_by_root(&self, root: &Path) -> Option<Target> {
+        self.packages().filter_map(|pkg| pkg.targets(self).find(|it| it.root(self) == root)).next()
+    }
+}