Bootstrap geth Rust workspace

crates/geth-config/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "geth-config"
+version = "0.1.0"
+edition.workspace = true
+rust-version.workspace = true
+license.workspace = true
+
+[dependencies]
+directories.workspace = true
+serde.workspace = true
+thiserror.workspace = true

crates/geth-config/src/lib.rs

@@ -0,0 +1,81 @@
+use std::path::{Path, PathBuf};
+
+#[derive(Clone, Debug)]
+pub struct GethPaths {
+    home: PathBuf,
+}
+
+impl GethPaths {
+    pub fn resolve() -> Result<Self, ConfigError> {
+        if let Some(home) = std::env::var_os("GETH_HOME") {
+            return Ok(Self {
+                home: PathBuf::from(home),
+            });
+        }
+        let project_dirs = directories::ProjectDirs::from("local", "geth", "geth")
+            .ok_or(ConfigError::NoDataDirectory)?;
+        Ok(Self {
+            home: project_dirs.data_dir().to_path_buf(),
+        })
+    }
+
+    #[must_use]
+    pub fn from_home(home: impl Into<PathBuf>) -> Self {
+        Self { home: home.into() }
+    }
+
+    #[must_use]
+    pub fn home(&self) -> &Path {
+        &self.home
+    }
+
+    #[must_use]
+    pub fn config_file(&self) -> PathBuf {
+        self.home.join("config.toml")
+    }
+
+    #[must_use]
+    pub fn metadata_db(&self) -> PathBuf {
+        self.home.join("geth.sqlite")
+    }
+
+    #[must_use]
+    pub fn identity_dir(&self) -> PathBuf {
+        self.home.join("identity")
+    }
+
+    #[must_use]
+    pub fn agent_key(&self) -> PathBuf {
+        self.identity_dir().join("agent.ed25519")
+    }
+
+    #[must_use]
+    pub fn cas_dir(&self) -> PathBuf {
+        self.home.join("cas")
+    }
+
+    #[must_use]
+    pub fn run_dir(&self) -> PathBuf {
+        self.home.join("run")
+    }
+
+    #[must_use]
+    pub fn socket_path(&self) -> PathBuf {
+        self.run_dir().join("geth.sock")
+    }
+
+    pub fn ensure_base_dirs(&self) -> Result<(), ConfigError> {
+        std::fs::create_dir_all(self.identity_dir())?;
+        std::fs::create_dir_all(self.cas_dir().join("blobs"))?;
+        std::fs::create_dir_all(self.run_dir())?;
+        Ok(())
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum ConfigError {
+    #[error("could not determine OS data directory and GETH_HOME is unset")]
+    NoDataDirectory,
+    #[error("io error: {0}")]
+    Io(#[from] std::io::Error),
+}