Switch to a plugin system

src/app.rs

@@ -1,4 +1,4 @@
-use color_eyre::eyre::Result;
+use color_eyre::eyre::{Result, WrapErr};
 use crossterm::event::KeyEvent;
 use ratatui::prelude::Rect;
 use serde::{Deserialize, Serialize};
@@ -6,6 +6,7 @@ use tokio::sync::mpsc;
 
 use crate::{
   action::Action,
+  commands::RataCommands,
   components::{fps::FpsCounter, home::Home, Component},
   config::Config,
   mode::Mode,
@@ -14,6 +15,7 @@ use crate::{
 
 pub struct App {
   pub config: Config,
+  pub commands: RataCommands,
   pub tick_rate: f64,
   pub frame_rate: f64,
   pub components: Vec<Box<dyn Component>>,
@@ -29,16 +31,19 @@ impl App {
     let fps = FpsCounter::default();
     let config = Config::new()?;
     let mode = Mode::Home;
-    Ok(Self {
+    let mut app = Self {
       tick_rate,
       frame_rate,
       components: vec![Box::new(home), Box::new(fps)],
       should_quit: false,
       should_suspend: false,
       config,
+      commands: RataCommands::new(),
       mode,
       last_tick_key_events: Vec::new(),
-    })
+    };
+    crate::plugins::load_all(&mut app).context("Could not load plugins")?;
+    Ok(app)
   }
 
   pub async fn run(&mut self) -> Result<()> {
@@ -73,7 +78,7 @@ impl App {
             if let Some(keymap) = self.config.keybindings.get(&self.mode) {
               if let Some(command_line) = keymap.get(&vec![key]) {
                 log::info!("Got command: {command_line}");
-                crate::commands::run_command(command_line, &action_tx)?;
+                crate::commands::run_command(command_line, &self, &action_tx)?;
               } else {
                 // If the key was not handled as a single key action,
                 // then consider it for multi-key combinations.
@@ -82,7 +87,7 @@ impl App {
                 // Check for multi-key combinations
                 if let Some(command_line) = keymap.get(&self.last_tick_key_events) {
                   log::info!("Got command: {command_line}");
-                  crate::commands::run_command(command_line, &action_tx)?;
+                  crate::commands::run_command(command_line, &self, &action_tx)?;
                 }
               }
             };

src/commands/mod.rs

@@ -14,21 +14,35 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+use std::collections::HashMap;
+
 use clap::{ArgMatches, Command, Parser};
 use color_eyre::eyre::{anyhow, bail, Result, WrapErr};
 use tokio::sync::mpsc;
 
 use crate::action::Action;
 
-pub type CommandHandler = fn(&str, &str, &mpsc::UnboundedSender<Action>) -> Result<()>;
+pub type CommandHandler = Box<dyn Fn(&str, &str, &mpsc::UnboundedSender<Action>) -> Result<()>>;
 
-pub struct RataCommand {
-  pub name: &'static str,
-  pub help: &'static str,
-  pub handler: CommandHandler,
+pub trait RataCommand {
+  fn name(&self) -> String;
+  fn help(&self) -> String;
+  fn handler(&self) -> CommandHandler;
 }
 
-inventory::collect!(RataCommand);
+pub struct RataCommands(pub HashMap<String, Box<dyn RataCommand>>);
+
+impl RataCommands {
+  pub fn new() -> RataCommands {
+    RataCommands(HashMap::new())
+  }
+
+  pub fn register(&mut self, command: Box<dyn RataCommand>) {
+    if let Some(previous_command) = self.0.insert(command.name(), command) {
+      log::info!("Overriding existing command {}", previous_command.name());
+    }
+  }
+}
 
 /*
 pub fn parser() -> Command {
@@ -45,7 +59,11 @@ pub fn parser() -> Command {
   )
 }*/
 
-pub fn run_command(command_line: &str, action_tx: &mpsc::UnboundedSender<Action>) -> Result<()> {
+pub fn run_command(
+  command_line: &str,
+  app: &crate::App,
+  action_tx: &mpsc::UnboundedSender<Action>,
+) -> Result<()> {
   if command_line.bytes().nth(0) != Some(b'/') {
     bail!("Not a command: {}", command_line);
   }
@@ -55,45 +73,8 @@ pub fn run_command(command_line: &str, action_tx: &mpsc::UnboundedSender<Action>
     None => (&command_line[1..], ""),
   };
 
-  for command in inventory::iter::<RataCommand>() {
-    if command.name == command_name.to_ascii_lowercase() {
-      return (command.handler)(command_name, args, action_tx);
-    }
-  }
-
-  bail!("Unknown command /{}", command_name)
-}
-
-inventory::submit! {
-  RataCommand {
-    name: "quit",
-    help: "Exits the process",
-    handler: quit_handler,
+  match app.commands.0.get(&command_name.to_ascii_lowercase()) {
+    Some(command) => command.handler()(command_name, args, action_tx),
+    None => bail!("Unknown command /{}", command_name),
   }
 }
-
-fn quit_handler(_name: &str, _args: &str, action_tx: &mpsc::UnboundedSender<Action>) -> Result<()> {
-  action_tx
-    .send(Action::Quit)
-    .context("Could not queue quit action")?;
-  Ok(())
-}
-
-inventory::submit! {
-  RataCommand {
-    name: "suspend",
-    help: "Puts the process in the background",
-    handler: suspend_handler,
-  }
-}
-
-fn suspend_handler(
-  _name: &str,
-  _args: &str,
-  action_tx: &mpsc::UnboundedSender<Action>,
-) -> Result<()> {
-  action_tx
-    .send(Action::Suspend)
-    .context("Could not queue suspend action")?;
-  Ok(())
-}

src/main.rs

@@ -9,6 +9,7 @@ pub mod commands;
 pub mod components;
 pub mod config;
 pub mod mode;
+pub mod plugins;
 pub mod tui;
 pub mod utils;
 

src/plugins/core.rs

@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2023  Valentin Lorentz
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+use color_eyre::eyre::{Result, WrapErr};
+use tokio::sync::mpsc;
+
+use crate::action::Action;
+use crate::commands::{CommandHandler, RataCommand};
+use crate::plugins::{Plugin, PluginGetter, PrePlugin};
+
+inventory::submit! {
+  PluginGetter(get_core)
+}
+
+fn get_core() -> Result<Box<dyn PrePlugin>> {
+  Ok(Box::new(Core {}))
+}
+
+struct Core {}
+
+impl PrePlugin for Core {
+  fn name(&self) -> String {
+    "core".to_owned()
+  }
+
+  fn help(&self) -> String {
+    "core utilities".to_owned()
+  }
+
+  fn load(self: Box<Self>, app: &mut crate::App) -> Result<Box<dyn Plugin>> {
+    app.commands.register(ActionCommand::new(
+      "quit",
+      "Exits the process",
+      Action::Quit,
+    ));
+    app.commands.register(ActionCommand::new(
+      "suspend",
+      "Puts the process in the background",
+      Action::Suspend,
+    ));
+    Ok(self)
+  }
+}
+
+impl Plugin for Core {}
+
+struct ActionCommand {
+  pub name: &'static str,
+  pub help: &'static str,
+  pub action: Action,
+}
+
+impl ActionCommand {
+  pub fn new(name: &'static str, help: &'static str, action: Action) -> Box<dyn RataCommand> {
+    Box::new(ActionCommand { name, help, action })
+  }
+}
+
+impl RataCommand for ActionCommand {
+  fn name(&self) -> String {
+    self.name.to_owned()
+  }
+  fn help(&self) -> String {
+    self.help.to_owned()
+  }
+  fn handler(&self) -> CommandHandler {
+    let action = self.action.clone();
+    Box::new(move |_name, _args, action_tx| {
+      action_tx
+        .send(action.clone())
+        .context("Could not queue quit action")
+    })
+  }
+}

src/plugins/mod.rs

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2023  Valentin Lorentz
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+use color_eyre::eyre::{Result, WrapErr};
+
+use crate::App;
+
+pub mod core;
+
+/// A [`Plugin`] that is not initialized yet
+pub trait PrePlugin {
+  fn name(&self) -> String;
+  fn help(&self) -> String;
+  fn load(self: Box<Self>, app: &mut App) -> Result<Box<dyn Plugin>>;
+}
+
+pub trait Plugin: PrePlugin {}
+
+pub struct PluginGetter(pub fn() -> Result<Box<dyn PrePlugin>>);
+
+inventory::collect!(PluginGetter);
+
+pub fn load_all(app: &mut App) -> Result<()> {
+  for plugin_getter in inventory::iter::<PluginGetter>() {
+    // TODO: skip failing plugins instead of stopping load altogether
+    let pre_plugin = (plugin_getter.0)().context("Could not get new plugin")?;
+    let name = pre_plugin.name();
+    pre_plugin
+      .load(app)
+      .with_context(|| format!("Could not load plugin {}", name))?;
+  }
+
+  Ok(())
+}