feat(managers): npm adapter

Cargo.toml

@@ -4,8 +4,14 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+serde = { version = "1.0.229", features = ["derive"] }
+serde_json = "1.0.154"
 slint = { version = "1", features = ["unstable-winit-030"] }
 thiserror = "2"
+which = "8.0.6"
 
 [build-dependencies]
 slint-build = "1"
+
+[dev-dependencies]
+tempfile = "3.27.0"

src/managers/manifest.rs

@@ -0,0 +1,109 @@
+use std::collections::BTreeMap;
+use std::fs;
+use std::path::Path;
+
+use serde::Deserialize;
+use serde::de::IgnoredAny;
+
+/// The parts of a Node `package.json` Libee cares about. Shared by npm, pnpm and Yarn.
+#[derive(Debug, Default, Deserialize)]
+pub struct Manifest {
+    pub description: Option<String>,
+    #[serde(default, deserialize_with = "homepage")]
+    pub homepage: Option<String>,
+    #[serde(default)]
+    bin: Option<Bin>,
+    #[serde(default)]
+    dependencies: BTreeMap<String, String>,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(untagged)]
+enum Bin {
+    Named(BTreeMap<String, String>),
+    Single(IgnoredAny),
+}
+
+/// Some manifests put an object or a list here instead of a URL; ignore those.
+fn homepage<'de, D: serde::Deserializer<'de>>(deserializer: D) -> Result<Option<String>, D::Error> {
+    Ok(match serde_json::Value::deserialize(deserializer)? {
+        serde_json::Value::String(url) => Some(url),
+        _ => None,
+    })
+}
+
+impl Manifest {
+    /// A missing or broken manifest must not abort the whole scan.
+    pub fn read(package_dir: &Path) -> Option<Self> {
+        let content = fs::read_to_string(package_dir.join("package.json")).ok()?;
+        serde_json::from_str(&content).ok()
+    }
+
+    pub fn binaries(&self, package_name: &str) -> Vec<String> {
+        match &self.bin {
+            Some(Bin::Named(bins)) => bins.keys().cloned().collect(),
+            Some(Bin::Single(_)) => {
+                let unscoped = package_name.rsplit('/').next().unwrap_or(package_name);
+                vec![unscoped.to_owned()]
+            }
+            None => Vec::new(),
+        }
+    }
+
+    pub fn dependencies(&self) -> Vec<String> {
+        self.dependencies.keys().cloned().collect()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::fs;
+
+    use super::Manifest;
+
+    fn manifest(json: &str) -> Manifest {
+        let dir = tempfile::tempdir().unwrap();
+        fs::write(dir.path().join("package.json"), json).unwrap();
+        Manifest::read(dir.path()).unwrap()
+    }
+
+    #[test]
+    fn reads_named_binaries_and_dependencies() {
+        let manifest = manifest(
+            r#"{ "description": "TypeScript compiler", "homepage": "https://www.typescriptlang.org",
+                 "bin": { "tsc": "bin/tsc", "tsserver": "bin/tsserver" },
+                 "dependencies": { "semver": "^7.0.0" } }"#,
+        );
+
+        assert_eq!(manifest.description.as_deref(), Some("TypeScript compiler"));
+        assert_eq!(
+            manifest.homepage.as_deref(),
+            Some("https://www.typescriptlang.org")
+        );
+        assert_eq!(manifest.binaries("typescript"), ["tsc", "tsserver"]);
+        assert_eq!(manifest.dependencies(), ["semver"]);
+    }
+
+    #[test]
+    fn single_binary_is_named_after_the_unscoped_package() {
+        let manifest = manifest(r#"{ "bin": "./cli.js" }"#);
+
+        assert_eq!(manifest.binaries("@angular/cli"), ["cli"]);
+    }
+
+    #[test]
+    fn ignores_non_string_homepage() {
+        let manifest = manifest(r#"{ "homepage": { "url": "x" } }"#);
+
+        assert!(manifest.homepage.is_none());
+    }
+
+    #[test]
+    fn missing_or_invalid_manifest_is_none() {
+        let dir = tempfile::tempdir().unwrap();
+        assert!(Manifest::read(dir.path()).is_none());
+
+        fs::write(dir.path().join("package.json"), "{ not json").unwrap();
+        assert!(Manifest::read(dir.path()).is_none());
+    }
+}

src/managers/mod.rs

@@ -1,7 +1,10 @@
 mod adapter;
 mod error;
+mod manifest;
+mod npm;
 mod runner;
 
 pub use adapter::{Capabilities, PackageManager};
 pub use error::ManagerError;
+pub use npm::Npm;
 pub use runner::{CommandOutput, CommandRunner, SystemRunner};