Add package.json discovery

crates/dinopkg-package-json/src/lib.rs

@@ -2,6 +2,8 @@ use std::collections::HashMap;
 
 use serde::{Deserialize, Serialize};
 
+mod util;
+
 #[derive(Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct PackageJson {
@@ -21,6 +23,18 @@ pub type Dependencies = HashMap<String, String>;
 pub enum Error {
     #[error("deserialization error: {0}")]
     Serde(#[from] serde_json::Error),
+
+    #[cfg(feature = "tokio")]
+    #[error("package.json not found")]
+    NotFound,
+
+    #[cfg(feature = "tokio")]
+    #[error("I/O error: {0}")]
+    Io(#[from] std::io::Error),
+
+    #[cfg(feature = "tokio")]
+    #[error("file is invalid utf-8")]
+    Utf8(#[from] std::string::FromUtf8Error),
 }
 
 impl PackageJson {
@@ -29,8 +43,12 @@ impl PackageJson {
     }
 
     #[cfg(feature = "tokio")]
-    pub async fn from_file() -> Result<Self, Error> {
-        let file = tokio::fs::read("package.json").await?;
+    pub async fn from_file(max_attempts: usize) -> Result<Self, Error> {
+        let path = util::find_package_json(max_attempts).await?;
+        let Some(path) = path else {
+            return Err(Error::NotFound);
+        };
+        let file = tokio::fs::read(path).await?;
         let file = String::from_utf8(file)?;
         Self::parse(&file)
     }

crates/dinopkg-package-json/src/util.rs

@@ -0,0 +1,21 @@
+use std::env;
+use std::path::PathBuf;
+
+use tokio::fs;
+
+use crate::Error;
+
+#[cfg(feature = "tokio")]
+pub async fn find_package_json(max_attempts: usize) -> Result<Option<PathBuf>, Error> {
+    let mut current_dir = env::current_dir()?;
+    for _ in 0..max_attempts {
+        let package_json_path = current_dir.join("package.json");
+        if fs::metadata(&package_json_path).await.is_ok() {
+            return Ok(Some(package_json_path));
+        }
+        if !current_dir.pop() {
+            break;
+        }
+    }
+    Ok(None)
+}