avoid parsing Cargo.toml

• forwards compatability hazard per MaulingMonkey/cargo-vs#5
• metadata has everything we need on modern cargo
• minor regression on e.g. cargo 1.47.0: might not generate docs/homepage links

Author: MaulingMonkey

src/metadata.rs

@@ -16,33 +16,26 @@ pub(crate) type PackageId = String;
 /// `{ ... }`
 #[derive(Deserialize, Debug)]
 pub(crate) struct Root {
-    #[serde(rename="workspace_root")]
-    pub workspace: WorkspaceRoot,
+    pub workspace_root: PathBuf,
     pub packages: Vec<PackageRef>,
     pub workspace_members: HashSet<PackageId>,
-    // metadata
+    pub metadata: Option<Metadata>,
     // ...
 }
 
-/// cargo metadata<br>
-/// `{ "workspace_root": "..." }`
-#[derive(Debug)]
-pub(crate) struct WorkspaceRoot {
-    pub dir:    PathBuf,
-    pub toml:   Option<WorkspaceToml>,
-}
-
 /// cargo metadata<br>
 /// `{ "packages": [ ... ] }`
 #[derive(Deserialize, Debug)]
 pub(crate) struct PackageRef {
-    #[serde(rename="manifest_path")]
-    pub manifest:   ManifestRef,
-    pub id:         PackageId,
-    pub name:       String,
-    pub version:    String,
-    pub targets:    Vec<PackageTarget>,
-    // metadata
+    pub manifest_path:  PathBuf,
+    pub id:             PackageId,
+    pub name:           String,
+    pub version:        String,
+    pub repository:     Option<Url>, // present in cargo +1.47.0 metadata
+    pub documentation:  Option<Url>, // MISSING in cargo +1.47.0 metadata, might lead to fewer tasks.json links in older cargo
+    pub homepage:       Option<Url>, // MISSING in cargo +1.47.0 metadata, might lead to fewer tasks.json links in older cargo
+    pub targets:        Vec<PackageTarget>,
+    pub metadata:       Option<Metadata>,
     // ...
 }
 
@@ -59,55 +52,10 @@ pub(crate) struct PackageTarget {
     //pub test:           bool,
 }
 
-
-
 /// cargo metadata<br>
-/// `{ "packages": [ { "manifest_path": "..." } ] }`
-#[derive(Debug)]
-pub(crate) struct ManifestRef {
-    pub path:   PathBuf,
-    pub toml:   Manifest,
-}
-
-
-
-/// Cargo.toml<br>
-/// (root - might contains `[workspace]`)
-#[derive(Deserialize, Debug)]
-pub(crate) struct WorkspaceToml {
-    #[serde(default)]
-    pub metadata: Metadata,
-}
-
-/// Cargo.toml<br>
-/// (root - expected to contain `[package]`)
-#[derive(Deserialize, Debug)]
-pub(crate) struct Manifest {
-    pub package: Package,
-    #[serde(default)]
-    pub metadata: Metadata,
-    // ...
-}
-
-
-/// Cargo.toml<br>
-/// `[package]`
+/// `{ "packages": [ { "metadata": {...} } ] }` or<br>
+/// `{ "metadata": {...} }` (workspace)
 #[derive(Deserialize, Debug)]
-pub(crate) struct Package {
-    pub name:           String,
-    pub version:        String,
-    pub repository:     Option<Url>,
-    pub documentation:  Option<Url>,
-    pub homepage:       Option<Url>,
-    #[serde(default)]
-    pub metadata:       Metadata,
-    // ...
-}
-
-/// Cargo.toml<br>
-/// `[package.metadata]` or<br>
-/// `[workspace.metadata]`
-#[derive(Deserialize, Debug, Default)]
 pub(crate) struct Metadata {
     pub local_install: Option<de::IgnoredAny>,
     #[serde(rename="cargo-vsc")] #[serde(default)] pub cargo_vsc: MetadataCargoVsc,
@@ -140,33 +88,3 @@ impl Root {
         serde_json::from_str(&stdout).map_err(|err| io::Error::new(io::ErrorKind::InvalidData, err))
     }
 }
-
-impl<'de> Deserialize<'de> for WorkspaceRoot {
-    fn deserialize<D: Deserializer<'de>>(d: D) -> Result<Self, D::Error> {
-        let dir = PathBuf::deserialize(d)?;
-        let file = dir.join("Cargo.toml");
-        let text = match std::fs::read_to_string(&file) {
-            Ok(text) => text,
-            Err(err) if err.kind() == io::ErrorKind::NotFound => return Ok(Self { dir, toml: None }),
-            Err(err) => return Err(de::Error::custom(&format!("unable to read {}: {}", file.display(), err))),
-        };
-        Ok(Self {
-            toml: Some(toml::from_str(&text).map_err(|err| de::Error::custom(&format!("unable to parse {}: {}", file.display(), err)))?),
-            dir,
-        })
-    }
-}
-
-impl<'de> Deserialize<'de> for ManifestRef {
-    fn deserialize<D: Deserializer<'de>>(d: D) -> Result<Self, D::Error> {
-        let path = PathBuf::deserialize(d)?;
-        let text = match std::fs::read_to_string(&path) {
-            Ok(text) => text,
-            Err(err) => return Err(de::Error::custom(&format!("unable to read {}: {}", path.display(), err))),
-        };
-        Ok(Self {
-            toml: toml::from_str(&text).map_err(|err| de::Error::custom(&format!("unable to parse {}: {}", path.display(), err)))?,
-            path,
-        })
-    }
-}

src/run.rs

@@ -22,7 +22,7 @@ pub fn run() {
 }
 
 fn create_vscode_dir(meta: &metadata::Root) -> io::Result<PathBuf> {
-    let vscode = meta.workspace.dir.join(".vscode");
+    let vscode = meta.workspace_root.join(".vscode");
     match std::fs::create_dir(&vscode) {
         Ok(()) => {
             std::fs::write(vscode.join(".gitignore"), "*").map_err(|err| io::Error::new(err.kind(), format!("unable to create .gitignore: {}", err)))?; // XXX: remap err for more context?
@@ -171,10 +171,10 @@ fn create_vscode_tasks_json(Context { meta, vscode, .. }: &Context) -> io::Resul
     let path = vscode.join("tasks.json");
     let mut o = create_json(&path)?;
 
-    let has_any_local_install = meta.workspace.toml.as_ref().map_or(false, |ws| ws.metadata.local_install.is_some());
+    let has_any_local_install = meta.metadata.as_ref().and_then(|m| m.local_install).is_some();
     // TODO: also install for packages: meta.packages.iter().any(|p| meta.workspace_members.contains(&p.id) && p.manifest.toml.metadata.local_install.is_some());
 
-    let simple = meta.workspace.toml.as_ref().and_then(|ws| ws.metadata.cargo_vsc.simple).unwrap_or(true);
+    let simple = meta.metadata.as_ref().and_then(|m| m.cargo_vsc.simple).unwrap_or(true);
 
     writeln!(o, "{{")?;
     writeln!(o, "    \"version\":          \"2.0.0\",")?;
@@ -322,13 +322,13 @@ fn create_vscode_tasks_json(Context { meta, vscode, .. }: &Context) -> io::Resul
             }
         }
 
-        if let Some(repository) = package.manifest.toml.package.repository.as_ref() {
+        if let Some(repository) = package.repository.as_ref() {
             write_open_link(&mut o, &format!("open repository ({})", package.name), &repository, "")?;
         }
-        if let Some(documentation) = package.manifest.toml.package.documentation.as_ref() {
+        if let Some(documentation) = package.documentation.as_ref() {
             write_open_link(&mut o, &format!("open documentation ({})", package.name), &documentation, "")?;
         }
-        if let Some(homepage) = package.manifest.toml.package.homepage.as_ref() {
+        if let Some(homepage) = package.homepage.as_ref() {
             write_open_link(&mut o, &format!("open homepage ({})", package.name), &homepage, "")?;
         }
     }