config: add documentation

jay-config/src/exec.rs

@@ -0,0 +1,50 @@
+//! Tools for spawning programs.
+
+use std::collections::HashMap;
+
+/// Sets an environment variable.
+///
+/// This does not affect the compositor itself but only programs spawned by the compositor.
+pub fn set_env(key: &str, val: &str) {
+    get!().set_env(key, val);
+}
+
+/// A command to be spawned.
+pub struct Command {
+    pub(crate) prog: String,
+    pub(crate) args: Vec<String>,
+    pub(crate) env: HashMap<String, String>,
+}
+
+impl Command {
+    /// Creates a new command to be spawned.
+    ///
+    /// `prog` should be the path to the program being spawned. If `prog` does not contain
+    /// a `/`, then it will be searched in `PATH` similar to how a shell would do it.
+    ///
+    /// The first argument passed to `prog`, `argv[0]`, is `prog` itself.
+    pub fn new(prog: &str) -> Self {
+        Self {
+            prog: prog.to_string(),
+            args: vec![],
+            env: Default::default(),
+        }
+    }
+
+    /// Adds an argument to be passed to the command.
+    pub fn arg(&mut self, arg: &str) -> &mut Self {
+        self.args.push(arg.to_string());
+        self
+    }
+
+    /// Sets an environment variable for this command only.
+    pub fn env(&mut self, key: &str, val: &str) -> &mut Self {
+        self.env.insert(key.to_string(), val.to_string());
+        self
+    }
+
+    /// Executes the command.
+    pub fn spawn(&self) {
+        get!().spawn(self);
+    }
+}