Drop daemonizing logic

Run in foreground, which is what service managers expect. Usages like
running `exec swww` in sway's config continue to work fine. User session
start-up scripts can simply run `swww &`.

Fixes: #182

src/cli.rs

@@ -172,13 +172,6 @@ pub enum Swww {
     /// Exits if there is already a daemon running. We check that by seeing if
     /// $XDG_RUNTIME_DIR/swww.socket exists.
     Init {
-        ///Don't fork the daemon. This will keep it running in the current terminal.
-        ///
-        ///The only advantage of this would be seeing the logging real time. Note that for release
-        ///builds we only log info, warnings and errors, so you won't be seeing much (ideally).
-        #[clap(long)]
-        no_daemon: bool,
-
         ///Don't load the cache *during initialization* (it still loads on monitor (re)connection)
         ///
         ///If want to always pass an image for `swww` to load, this option can help make the

src/main.rs

@@ -1,5 +1,9 @@
 use clap::Parser;
-use std::{path::PathBuf, process::Stdio, time::Duration};
+use std::{
+    os::unix::{net::UnixStream, process::CommandExt},
+    path::PathBuf,
+    time::Duration,
+};
 
 use utils::{
     cache,
@@ -14,10 +18,7 @@ use cli::{ResizeStrategy, Swww};
 
 fn main() -> Result<(), String> {
     let swww = Swww::parse();
-    if let Swww::Init {
-        no_daemon, format, ..
-    } = &swww
-    {
+    if let Swww::Init { .. } = &swww {
         eprintln!(
             "DEPRECATION WARNING: `swww init` IS DEPRECATED. Call `swww-daemon` directly instead"
         );
@@ -49,10 +50,7 @@ fn main() -> Result<(), String> {
                 }
             }
         }
-        spawn_daemon(*no_daemon, format)?;
-        if *no_daemon {
-            return Ok(());
-        }
+        return Err(spawn_daemon());
     }
 
     if let Swww::ClearCache = &swww {
@@ -282,30 +280,11 @@ fn split_cmdline_outputs(outputs: &str) -> Box<[String]> {
         .collect()
 }
 
-fn spawn_daemon(no_daemon: bool, format: &Option<cli::PixelFormat>) -> Result<(), String> {
+/// Only returns if `exec` fails.
+fn spawn_daemon() -> String {
     let mut cmd = std::process::Command::new("swww-daemon");
-
-    if let Some(format) = format {
-        cmd.arg("--format");
-        cmd.arg(match format {
-            cli::PixelFormat::Xrgb => "xrgb",
-            cli::PixelFormat::Xbgr => "xbgr",
-            cli::PixelFormat::Rgb => "rgb",
-            cli::PixelFormat::Bgr => "bgr",
-        });
-    }
-
-    if no_daemon {
-        match cmd.status() {
-            Ok(_) => Ok(()),
-            Err(e) => Err(format!("error spawning swww-daemon: {e}")),
-        }
-    } else {
-        match cmd.stdout(Stdio::null()).stderr(Stdio::null()).spawn() {
-            Ok(_) => Ok(()),
-            Err(e) => Err(format!("error spawning swww-daemon: {e}")),
-        }
-    }
+    let err = cmd.exec();
+    format!("failed to exec into swww-daemon: {err}")
 }
 
 fn is_daemon_running() -> Result<bool, String> {