Run detached and reload config liveHEADmain

1 files changed, 84 insertions, 14 deletions

diff --git a/src/config.rs b/src/config.rs
index 4e41069..d354839 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1,11 +1,15 @@
 use crate::color::Color;
 use crate::protocol::{zwlr_layer_shell_v1, zwlr_layer_surface_v1};
 use anyhow::{Context, Result};
+use inotify::{Inotify, WatchMask};
 use pangocairo::pango::FontDescription;
 use serde::{Deserialize, de};
 use std::collections::HashMap;
+use std::ffi::OsString;
 use std::fs::read_to_string;
+use std::io;
 use std::ops::Deref;
+use std::os::fd::{AsRawFd, RawFd};
 use std::path::{Path, PathBuf};
 use std::{env, fmt};
 
@@ -114,27 +118,21 @@ impl Default for Config {
 
 impl Config {
     pub fn new(path: Option<&Path>) -> Result<Self> {
-        let buf;
-
-        let path = match path {
-            Some(path) => Some(path),
-            None => {
-                buf = config_path();
-                buf.as_deref()
-            }
-        };
-
-        Ok(match path {
+        match Self::path(path) {
             Some(config_path) => {
                 let config = read_to_string(config_path).context("Failed to read configuration")?;
-                toml::from_str(&config).context("Failed to deserialize configuration")?
+                toml::from_str(&config).context("Failed to deserialize configuration")
             }
             None => {
                 eprintln!("Could not find the configuration path");
                 eprintln!("Using default configuration");
-                Self::default()
+                Ok(Self::default())
             }
-        })
+        }
+    }
+
+    pub fn path(path: Option<&Path>) -> Option<PathBuf> {
+        path.map(Path::to_path_buf).or_else(config_path)
     }
 
     pub fn output_enabled(&self, output: &str) -> bool {
@@ -145,6 +143,47 @@ impl Config {
     }
 }
 
+pub struct ConfigWatcher {
+    inotify: Inotify,
+    buffer: Vec<u8>,
+    filename: OsString,
+}
+
+impl ConfigWatcher {
+    pub fn new(path: &Path) -> io::Result<Self> {
+        let directory = path
+            .parent()
+            .filter(|parent| !parent.as_os_str().is_empty())
+            .unwrap_or_else(|| Path::new("."));
+        let filename = path
+            .file_name()
+            .ok_or_else(|| io::Error::new(io::ErrorKind::InvalidInput, "invalid config path"))?
+            .to_os_string();
+        let inotify = Inotify::init()?;
+        inotify.watches().add(
+            directory,
+            WatchMask::CLOSE_WRITE | WatchMask::CREATE | WatchMask::MOVED_TO,
+        )?;
+        Ok(Self {
+            inotify,
+            buffer: vec![0; 4096],
+            filename,
+        })
+    }
+
+    pub fn fd(&self) -> RawFd {
+        self.inotify.as_raw_fd()
+    }
+
+    pub fn changed(&mut self) -> io::Result<bool> {
+        let mut changed = false;
+        for event in self.inotify.read_events(&mut self.buffer)? {
+            changed |= event.name.is_some_and(|name| name == self.filename);
+        }
+        Ok(changed)
+    }
+}
+
 fn config_dir() -> Option<PathBuf> {
     env::var_os("XDG_CONFIG_HOME")
         .map(PathBuf::from)
@@ -296,3 +335,34 @@ impl<'de> de::Deserialize<'de> for Font {
         deserializer.deserialize_str(FontVisitor)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::ConfigWatcher;
+    use std::fs;
+    use std::time::{SystemTime, UNIX_EPOCH};
+
+    #[test]
+    fn watcher_detects_overwrite_and_atomic_replacement() {
+        let unique = SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .unwrap()
+            .as_nanos();
+        let directory =
+            std::env::temp_dir().join(format!("i3bar-mango-{unique}-{}", std::process::id()));
+        let config_path = directory.join("config.toml");
+        let replacement_path = directory.join("config.toml.new");
+        fs::create_dir(&directory).unwrap();
+        fs::write(&config_path, "height = 24").unwrap();
+
+        let mut watcher = ConfigWatcher::new(&config_path).unwrap();
+        fs::write(&config_path, "height = 25").unwrap();
+        assert!(watcher.changed().unwrap());
+
+        fs::write(&replacement_path, "height = 26").unwrap();
+        fs::rename(&replacement_path, &config_path).unwrap();
+        assert!(watcher.changed().unwrap());
+
+        fs::remove_dir_all(directory).unwrap();
+    }
+}