Locate data dir on Linux and Windows

gdn/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "gdn"
+version = { workspace = true }
+edition = { workspace = true }
+
+[dependencies]
+directories.workspace = true
+
+[lints]
+workspace = true

gdn/src/lib.rs

@@ -0,0 +1,7 @@
+mod paths;
+
+pub use crate::paths::Paths;
+
+pub const PROPER_NAME: &str = "GedächtNAS";
+pub const TECHNICAL_NAME: &str = "gedaechtnas";
+pub const ABBREVIATED_NAME: &str = "gdn";

gdn/src/paths.rs

@@ -0,0 +1,27 @@
+use std::path::PathBuf;
+
+use directories::ProjectDirs;
+
+pub struct Paths(ProjectDirs);
+
+impl Paths {
+    pub fn on_linux() -> Option<Self> {
+        ProjectDirs::from("de", "plugh", crate::TECHNICAL_NAME).map(Self)
+    }
+
+    pub fn on_windows() -> Option<Self> {
+        ProjectDirs::from("de", "plugh", crate::PROPER_NAME).map(Self)
+    }
+
+    pub fn state_file(&self) -> PathBuf {
+        self.0.data_local_dir().join("state.json")
+    }
+
+    pub fn repos_dir(&self) -> PathBuf {
+        self.0.data_local_dir().join("repos")
+    }
+
+    pub fn repo_dir(&self, name: &str) -> PathBuf {
+        self.repos_dir().join(format!("{name}.git"))
+    }
+}