Decouple project loading from project discovery a bit

3 files changed, 163 insertions, 128 deletions

diff --git a/crates/ra_project_model/src/lib.rs b/crates/ra_project_model/src/lib.rs
index 0ab64a1e0..df4be94dc 100644
--- a/crates/ra_project_model/src/lib.rs
+++ b/crates/ra_project_model/src/lib.rs
@@ -77,31 +77,131 @@ impl PackageRoot {
     }
 }
 
-impl ProjectWorkspace {
-    pub fn discover(path: &Path, cargo_features: &CargoConfig) -> Result<ProjectWorkspace> {
-        ProjectWorkspace::discover_with_sysroot(path, true, cargo_features)
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum ProjectRoot {
+    ProjectJson(PathBuf),
+    CargoToml(PathBuf),
+}
+
+impl ProjectRoot {
+    pub fn from_manifest_file(path: PathBuf) -> Result<ProjectRoot> {
+        if path.ends_with("rust-project.json") {
+            return Ok(ProjectRoot::ProjectJson(path));
+        }
+        if path.ends_with("Cargo.toml") {
+            return Ok(ProjectRoot::CargoToml(path));
+        }
+        bail!("project root must point to Cargo.toml or rust-project.json: {}", path.display())
     }
 
-    pub fn discover_with_sysroot(
-        path: &Path,
-        with_sysroot: bool,
+    pub fn discover(path: &Path) -> Result<ProjectRoot, CargoTomlNotFoundError> {
+        if let Some(project_json) = find_rust_project_json(path) {
+            return Ok(ProjectRoot::ProjectJson(project_json));
+        }
+        return find_cargo_toml(path).map(ProjectRoot::CargoToml);
+
+        fn find_rust_project_json(path: &Path) -> Option<PathBuf> {
+            if path.ends_with("rust-project.json") {
+                return Some(path.to_path_buf());
+            }
+
+            let mut curr = Some(path);
+            while let Some(path) = curr {
+                let candidate = path.join("rust-project.json");
+                if candidate.exists() {
+                    return Some(candidate);
+                }
+                curr = path.parent();
+            }
+
+            None
+        }
+
+        fn find_cargo_toml(path: &Path) -> Result<PathBuf, CargoTomlNotFoundError> {
+            if path.ends_with("Cargo.toml") {
+                return Ok(path.to_path_buf());
+            }
+
+            if let Some(p) = find_cargo_toml_in_parent_dir(path) {
+                return Ok(p);
+            }
+
+            let entities = match read_dir(path) {
+                Ok(entities) => entities,
+                Err(e) => {
+                    return Err(CargoTomlNotFoundError {
+                        searched_at: path.to_path_buf(),
+                        reason: format!("file system error: {}", e),
+                    }
+                    .into());
+                }
+            };
+
+            let mut valid_canditates = find_cargo_toml_in_child_dir(entities);
+            return match valid_canditates.len() {
+                1 => Ok(valid_canditates.remove(0)),
+                0 => Err(CargoTomlNotFoundError {
+                    searched_at: path.to_path_buf(),
+                    reason: "no Cargo.toml file found".to_string(),
+                }
+                .into()),
+                _ => Err(CargoTomlNotFoundError {
+                    searched_at: path.to_path_buf(),
+                    reason: format!(
+                        "multiple equally valid Cargo.toml files found: {:?}",
+                        valid_canditates
+                    ),
+                }
+                .into()),
+            };
+        }
+
+        fn find_cargo_toml_in_parent_dir(path: &Path) -> Option<PathBuf> {
+            let mut curr = Some(path);
+            while let Some(path) = curr {
+                let candidate = path.join("Cargo.toml");
+                if candidate.exists() {
+                    return Some(candidate);
+                }
+                curr = path.parent();
+            }
+
+            None
+        }
+
+        fn find_cargo_toml_in_child_dir(entities: ReadDir) -> Vec<PathBuf> {
+            // Only one level down to avoid cycles the easy way and stop a runaway scan with large projects
+            let mut valid_canditates = vec![];
+            for entity in entities.filter_map(Result::ok) {
+                let candidate = entity.path().join("Cargo.toml");
+                if candidate.exists() {
+                    valid_canditates.push(candidate)
+                }
+            }
+            valid_canditates
+        }
+    }
+}
+
+impl ProjectWorkspace {
+    pub fn load(
+        root: ProjectRoot,
         cargo_features: &CargoConfig,
+        with_sysroot: bool,
     ) -> Result<ProjectWorkspace> {
-        match find_rust_project_json(path) {
-            Some(json_path) => {
-                let file = File::open(&json_path)
-                    .with_context(|| format!("Failed to open json file {}", json_path.display()))?;
+        let res = match root {
+            ProjectRoot::ProjectJson(project_json) => {
+                let file = File::open(&project_json).with_context(|| {
+                    format!("Failed to open json file {}", project_json.display())
+                })?;
                 let reader = BufReader::new(file);
-                Ok(ProjectWorkspace::Json {
+                ProjectWorkspace::Json {
                     project: from_reader(reader).with_context(|| {
-                        format!("Failed to deserialize json file {}", json_path.display())
+                        format!("Failed to deserialize json file {}", project_json.display())
                     })?,
-                })
+                }
             }
-            None => {
-                let cargo_toml = find_cargo_toml(path).with_context(|| {
-                    format!("Failed to find Cargo.toml for path {}", path.display())
-                })?;
+            ProjectRoot::CargoToml(cargo_toml) => {
                 let cargo = CargoWorkspace::from_cargo_metadata(&cargo_toml, cargo_features)
                     .with_context(|| {
                         format!(
@@ -119,9 +219,11 @@ impl ProjectWorkspace {
                 } else {
                     Sysroot::default()
                 };
-                Ok(ProjectWorkspace::Cargo { cargo, sysroot })
+                ProjectWorkspace::Cargo { cargo, sysroot }
             }
-        }
+        };
+
+        Ok(res)
     }
 
     /// Returns the roots for the current `ProjectWorkspace`
@@ -469,87 +571,6 @@ impl ProjectWorkspace {
     }
 }
 
-fn find_rust_project_json(path: &Path) -> Option<PathBuf> {
-    if path.ends_with("rust-project.json") {
-        return Some(path.to_path_buf());
-    }
-
-    let mut curr = Some(path);
-    while let Some(path) = curr {
-        let candidate = path.join("rust-project.json");
-        if candidate.exists() {
-            return Some(candidate);
-        }
-        curr = path.parent();
-    }
-
-    None
-}
-
-fn find_cargo_toml_in_parent_dir(path: &Path) -> Option<PathBuf> {
-    let mut curr = Some(path);
-    while let Some(path) = curr {
-        let candidate = path.join("Cargo.toml");
-        if candidate.exists() {
-            return Some(candidate);
-        }
-        curr = path.parent();
-    }
-
-    None
-}
-
-fn find_cargo_toml_in_child_dir(entities: ReadDir) -> Vec<PathBuf> {
-    // Only one level down to avoid cycles the easy way and stop a runaway scan with large projects
-    let mut valid_canditates = vec![];
-    for entity in entities.filter_map(Result::ok) {
-        let candidate = entity.path().join("Cargo.toml");
-        if candidate.exists() {
-            valid_canditates.push(candidate)
-        }
-    }
-    valid_canditates
-}
-
-fn find_cargo_toml(path: &Path) -> Result<PathBuf> {
-    if path.ends_with("Cargo.toml") {
-        return Ok(path.to_path_buf());
-    }
-
-    if let Some(p) = find_cargo_toml_in_parent_dir(path) {
-        return Ok(p);
-    }
-
-    let entities = match read_dir(path) {
-        Ok(entities) => entities,
-        Err(e) => {
-            return Err(CargoTomlNotFoundError {
-                searched_at: path.to_path_buf(),
-                reason: format!("file system error: {}", e),
-            }
-            .into());
-        }
-    };
-
-    let mut valid_canditates = find_cargo_toml_in_child_dir(entities);
-    match valid_canditates.len() {
-        1 => Ok(valid_canditates.remove(0)),
-        0 => Err(CargoTomlNotFoundError {
-            searched_at: path.to_path_buf(),
-            reason: "no Cargo.toml file found".to_string(),
-        }
-        .into()),
-        _ => Err(CargoTomlNotFoundError {
-            searched_at: path.to_path_buf(),
-            reason: format!(
-                "multiple equally valid Cargo.toml files found: {:?}",
-                valid_canditates
-            ),
-        }
-        .into()),
-    }
-}
-
 pub fn get_rustc_cfg_options() -> CfgOptions {
     let mut cfg_options = CfgOptions::default();
 
diff --git a/crates/rust-analyzer/src/cli/load_cargo.rs b/crates/rust-analyzer/src/cli/load_cargo.rs
index 43062ea10..f3f266ee4 100644
--- a/crates/rust-analyzer/src/cli/load_cargo.rs
+++ b/crates/rust-analyzer/src/cli/load_cargo.rs
@@ -8,7 +8,7 @@ use crossbeam_channel::{unbounded, Receiver};
 use ra_db::{ExternSourceId, FileId, SourceRootId};
 use ra_ide::{AnalysisChange, AnalysisHost};
 use ra_project_model::{
-    get_rustc_cfg_options, CargoConfig, PackageRoot, ProcMacroClient, ProjectWorkspace,
+    get_rustc_cfg_options, CargoConfig, PackageRoot, ProcMacroClient, ProjectRoot, ProjectWorkspace,
 };
 use ra_vfs::{RootEntry, Vfs, VfsChange, VfsTask, Watch};
 use rustc_hash::{FxHashMap, FxHashSet};
@@ -27,9 +27,11 @@ pub(crate) fn load_cargo(
     load_out_dirs_from_check: bool,
 ) -> Result<(AnalysisHost, FxHashMap<SourceRootId, PackageRoot>)> {
     let root = std::env::current_dir()?.join(root);
-    let ws = ProjectWorkspace::discover(
-        root.as_ref(),
+    let root = ProjectRoot::discover(&root)?;
+    let ws = ProjectWorkspace::load(
+        root,
         &CargoConfig { load_out_dirs_from_check, ..Default::default() },
+        true,
     )?;
 
     let mut extern_dirs = FxHashSet::default();
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index 8d1429196..9c345601c 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -88,37 +88,49 @@ pub fn main_loop(ws_roots: Vec<PathBuf>, config: Config, connection: Connection)
 
     let mut loop_state = LoopState::default();
     let mut world_state = {
-        // FIXME: support dynamic workspace loading.
         let workspaces = {
-            let mut loaded_workspaces = Vec::new();
-            for ws_root in &ws_roots {
-                let workspace = ra_project_model::ProjectWorkspace::discover_with_sysroot(
-                    ws_root.as_path(),
-                    config.with_sysroot,
-                    &config.cargo,
-                );
-                match workspace {
-                    Ok(workspace) => loaded_workspaces.push(workspace),
-                    Err(e) => {
-                        log::error!("loading workspace failed: {:?}", e);
-
-                        if let Some(ra_project_model::CargoTomlNotFoundError { .. }) =
-                            e.downcast_ref()
-                        {
-                            if !config.notifications.cargo_toml_not_found {
-                                continue;
-                            }
+            // FIXME: support dynamic workspace loading.
+            let mut visited = FxHashSet::default();
+            let project_roots = ws_roots
+                .iter()
+                .map(|it| ra_project_model::ProjectRoot::discover(it))
+                .filter_map(|dir| {
+                    dir.map_err(|cargo_toml_not_found| {
+                        log::error!("discovering workspace failed: {:?}", cargo_toml_not_found);
+
+                        if config.notifications.cargo_toml_not_found {
+                            show_message(
+                                req::MessageType::Error,
+                                format!(
+                                    "rust-analyzer failed to discover workspace: {:?}",
+                                    cargo_toml_not_found
+                                ),
+                                &connection.sender,
+                            );
                         }
-
+                    })
+                    .ok()
+                })
+                .filter(|it| visited.insert(it.clone()));
+
+            project_roots
+                .filter_map(|root| {
+                    ra_project_model::ProjectWorkspace::load(
+                        root,
+                        &config.cargo,
+                        config.with_sysroot,
+                    )
+                    .map_err(|err| {
+                        log::error!("failed to load workspace: {:#}", err);
                         show_message(
                             req::MessageType::Error,
-                            format!("rust-analyzer failed to load workspace: {:?}", e),
+                            format!("rust-analyzer failed to load workspace: {:#}", err),
                             &connection.sender,
                         );
-                    }
-                }
-            }
-            loaded_workspaces
+                    })
+                    .ok()
+                })
+                .collect::<Vec<_>>()
         };
 
         let globs = config