feat: config (#496)

* feat: default reth dirs

* docs: clarify txpool config docs

* feat: `serde` feature for `reth-consensus`

* feat: add missing hardforks

* feat: full chain specification

* feat: `DbPath` type

* feat: custom chain specs

* feat: `--debug.tip` option

* feat: basic stage config

* fix: resize db geometry

* refactor: don't commit in headers stage

* chore: remove headers dl timeout

* feat: loading of config

* refactor(config): `stage` -> `stages`

bin/reth/src/dirs.rs

@@ -0,0 +1,95 @@
+//! reth data directories.
+use crate::util::parse_path;
+use std::{
+    env::VarError,
+    fmt::{Debug, Display, Formatter},
+    path::{Path, PathBuf},
+    str::FromStr,
+};
+
+/// Returns the path to the reth data directory.
+///
+/// Refer to [dirs_next::data_dir] for cross-platform behavior.
+pub fn data_dir() -> Option<PathBuf> {
+    dirs_next::data_dir().map(|root| root.join("reth"))
+}
+
+/// Returns the path to the reth database.
+///
+/// Refer to [dirs_next::data_dir] for cross-platform behavior.
+pub fn database_path() -> Option<PathBuf> {
+    data_dir().map(|root| root.join("db"))
+}
+
+/// Returns the path to the reth configuration directory.
+///
+/// Refer to [dirs_next::config_dir] for cross-platform behavior.
+pub fn config_dir() -> Option<PathBuf> {
+    dirs_next::config_dir().map(|root| root.join("reth"))
+}
+
+/// A wrapper type that either parses a user-given path for the reth database or defaults to an
+/// OS-specific path.
+#[derive(Clone, Debug)]
+pub struct DbPath(PathBuf);
+
+impl Display for DbPath {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0.display())
+    }
+}
+
+impl Default for DbPath {
+    fn default() -> Self {
+        Self(database_path().expect("Could not determine default database path. Set one manually."))
+    }
+}
+
+impl FromStr for DbPath {
+    type Err = shellexpand::LookupError<VarError>;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(Self(parse_path(s)?))
+    }
+}
+
+impl AsRef<Path> for DbPath {
+    fn as_ref(&self) -> &Path {
+        self.0.as_path()
+    }
+}
+
+/// A wrapper type that either parses a user-given path for the reth config or defaults to an
+/// OS-specific path.
+#[derive(Clone, Debug)]
+pub struct ConfigPath(PathBuf);
+
+impl Display for ConfigPath {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0.display())
+    }
+}
+
+impl Default for ConfigPath {
+    fn default() -> Self {
+        Self(
+            config_dir()
+                .expect("Could not determine default database path. Set one manually.")
+                .join("reth.toml"),
+        )
+    }
+}
+
+impl FromStr for ConfigPath {
+    type Err = shellexpand::LookupError<VarError>;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(Self(parse_path(s)?))
+    }
+}
+
+impl AsRef<Path> for ConfigPath {
+    fn as_ref(&self) -> &Path {
+        self.0.as_path()
+    }
+}