feat: add mpv sidecar IPC and Tauri commands

Persistent BufReader + request_id matching for correct event handling. Audio-file passed during loadfile for frame-accurate sync. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-04-16 18:46:01 +02:00
parent b12758c53c
commit 2036c49b52
3 changed files with 237 additions and 6 deletions
@@ -0,0 +1,56 @@
+use tauri::State;
+use std::sync::Mutex;
+use crate::mpv::Mpv;
+
+pub struct MpvState(pub Mutex<Mpv>);
+
+#[tauri::command]
+pub fn mpv_start(state: State<MpvState>) -> Result<(), String> {
+    state.0.lock().unwrap().start()
+}
+
+#[tauri::command]
+pub fn mpv_stop(state: State<MpvState>) -> Result<(), String> {
+    state.0.lock().unwrap().stop();
+    Ok(())
+}
+
+#[tauri::command]
+pub fn mpv_load(state: State<MpvState>, video_url: String, audio_url: String) -> Result<(), String> {
+    state.0.lock().unwrap().load_file(&video_url, &audio_url)
+}
+
+#[tauri::command]
+pub fn mpv_seek(state: State<MpvState>, time: f64) -> Result<(), String> {
+    state.0.lock().unwrap().seek(time)
+}
+
+#[tauri::command]
+pub fn mpv_pause(state: State<MpvState>) -> Result<(), String> {
+    state.0.lock().unwrap().pause()
+}
+
+#[tauri::command]
+pub fn mpv_resume(state: State<MpvState>) -> Result<(), String> {
+    state.0.lock().unwrap().resume()
+}
+
+#[tauri::command]
+pub fn mpv_set_loop(state: State<MpvState>, a: f64, b: f64) -> Result<(), String> {
+    state.0.lock().unwrap().set_loop(a, b)
+}
+
+#[tauri::command]
+pub fn mpv_clear_loop(state: State<MpvState>) -> Result<(), String> {
+    state.0.lock().unwrap().clear_loop()
+}
+
+#[tauri::command]
+pub fn mpv_time_pos(state: State<MpvState>) -> Result<f64, String> {
+    state.0.lock().unwrap().time_pos()
+}
+
+#[tauri::command]
+pub fn mpv_duration(state: State<MpvState>) -> Result<f64, String> {
+    state.0.lock().unwrap().get_duration()
+}
@@ -1,14 +1,27 @@
-// Learn more about Tauri commands at https://tauri.app/develop/calling-rust/
-#[tauri::command]
-fn greet(name: &str) -> String {
-    format!("Hello, {}! You've been greeted from Rust!", name)
-}
+mod mpv;
+mod commands;
+
+use commands::MpvState;
+use mpv::Mpv;
+use std::sync::Mutex;

 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
    tauri::Builder::default()
        .plugin(tauri_plugin_opener::init())
-        .invoke_handler(tauri::generate_handler![greet])
+        .manage(MpvState(Mutex::new(Mpv::new())))
+        .invoke_handler(tauri::generate_handler![
+            commands::mpv_start,
+            commands::mpv_stop,
+            commands::mpv_load,
+            commands::mpv_seek,
+            commands::mpv_pause,
+            commands::mpv_resume,
+            commands::mpv_set_loop,
+            commands::mpv_clear_loop,
+            commands::mpv_time_pos,
+            commands::mpv_duration,
+        ])
        .run(tauri::generate_context!())
        .expect("error while running tauri application");
 }
@@ -0,0 +1,162 @@
+use std::io::{BufRead, BufReader, Write};
+use std::os::unix::net::UnixStream;
+use std::process::{Child, Command};
+use std::sync::atomic::{AtomicU64, Ordering};
+use serde_json::{json, Value};
+
+pub struct Mpv {
+    process: Option<Child>,
+    writer: Option<UnixStream>,
+    reader: Option<BufReader<UnixStream>>,
+    socket_path: String,
+    next_id: AtomicU64,
+}
+
+impl Mpv {
+    pub fn new() -> Self {
+        let socket_path = format!("/tmp/8cut-mpv-{}", std::process::id());
+        Mpv {
+            process: None,
+            writer: None,
+            reader: None,
+            socket_path,
+            next_id: AtomicU64::new(1),
+        }
+    }
+
+    pub fn start(&mut self) -> Result<(), String> {
+        self.stop();
+
+        let child = Command::new("mpv")
+            .args([
+                "--idle=yes",
+                "--force-window=no",
+                "--vo=null",
+                "--keep-open=yes",
+                &format!("--input-ipc-server={}", self.socket_path),
+            ])
+            .spawn()
+            .map_err(|e| format!("Failed to start mpv: {e}"))?;
+
+        self.process = Some(child);
+
+        // Wait for socket
+        for _ in 0..50 {
+            std::thread::sleep(std::time::Duration::from_millis(100));
+            if let Ok(stream) = UnixStream::connect(&self.socket_path) {
+                stream.set_nonblocking(false).ok();
+                let reader_stream = stream.try_clone().map_err(|e| e.to_string())?;
+                self.writer = Some(stream);
+                self.reader = Some(BufReader::new(reader_stream));
+                return Ok(());
+            }
+        }
+        Err("Timeout waiting for mpv IPC socket".into())
+    }
+
+    pub fn stop(&mut self) {
+        if let Some(ref mut child) = self.process {
+            child.kill().ok();
+            child.wait().ok();
+        }
+        self.process = None;
+        self.writer = None;
+        self.reader = None;
+        std::fs::remove_file(&self.socket_path).ok();
+    }
+
+    /// Send a command and wait for the matching response (by request_id).
+    /// Skips over asynchronous mpv events while waiting.
+    fn send_and_recv(&mut self, cmd: Value) -> Result<Value, String> {
+        let id = self.next_id.fetch_add(1, Ordering::Relaxed);
+        let writer = self.writer.as_mut().ok_or("mpv not running")?;
+        let reader = self.reader.as_mut().ok_or("mpv not running")?;
+
+        let mut msg_val = cmd;
+        msg_val["request_id"] = json!(id);
+        let mut msg = serde_json::to_string(&msg_val).unwrap();
+        msg.push('\n');
+        writer.write_all(msg.as_bytes()).map_err(|e| e.to_string())?;
+
+        // Read lines until we find the response matching our request_id
+        let mut line = String::new();
+        loop {
+            line.clear();
+            reader.read_line(&mut line).map_err(|e| e.to_string())?;
+            let parsed: Value = serde_json::from_str(&line).map_err(|e| e.to_string())?;
+            // mpv events have "event" key, responses have "request_id"
+            if parsed.get("request_id").and_then(|v| v.as_u64()) == Some(id) {
+                return Ok(parsed);
+            }
+            // Otherwise it's an async event — skip it
+        }
+    }
+
+    pub fn command(&mut self, args: &[&str]) -> Result<(), String> {
+        let resp = self.send_and_recv(json!({ "command": args }))?;
+        if resp.get("error").and_then(|e| e.as_str()) != Some("success") {
+            return Err(format!("mpv error: {}", resp.get("error").unwrap_or(&Value::Null)));
+        }
+        Ok(())
+    }
+
+    pub fn set_property(&mut self, name: &str, value: Value) -> Result<(), String> {
+        let resp = self.send_and_recv(json!({ "command": ["set_property", name, value] }))?;
+        if resp.get("error").and_then(|e| e.as_str()) != Some("success") {
+            return Err(format!("mpv error: {}", resp.get("error").unwrap_or(&Value::Null)));
+        }
+        Ok(())
+    }
+
+    pub fn get_property(&mut self, name: &str) -> Result<Value, String> {
+        let resp = self.send_and_recv(json!({ "command": ["get_property", name] }))?;
+        if resp.get("error").and_then(|e| e.as_str()) != Some("success") {
+            return Err(format!("mpv error: {}", resp.get("error").unwrap_or(&Value::Null)));
+        }
+        Ok(resp.get("data").cloned().unwrap_or(Value::Null))
+    }
+
+    pub fn load_file(&mut self, video_url: &str, audio_url: &str) -> Result<(), String> {
+        // Pass audio-file option during load so both streams sync from the start
+        let options = format!("audio-file={}", audio_url);
+        self.command(&["loadfile", video_url, "replace", &options])
+    }
+
+    pub fn seek(&mut self, time: f64) -> Result<(), String> {
+        self.command(&["seek", &time.to_string(), "absolute"])
+    }
+
+    pub fn pause(&mut self) -> Result<(), String> {
+        self.set_property("pause", json!(true))
+    }
+
+    pub fn resume(&mut self) -> Result<(), String> {
+        self.set_property("pause", json!(false))
+    }
+
+    pub fn set_loop(&mut self, a: f64, b: f64) -> Result<(), String> {
+        self.set_property("ab-loop-a", json!(a))?;
+        self.set_property("ab-loop-b", json!(b))
+    }
+
+    pub fn clear_loop(&mut self) -> Result<(), String> {
+        self.set_property("ab-loop-a", json!("no"))?;
+        self.set_property("ab-loop-b", json!("no"))
+    }
+
+    pub fn time_pos(&mut self) -> Result<f64, String> {
+        let val = self.get_property("time-pos")?;
+        val.as_f64().ok_or("time-pos not a number".into())
+    }
+
+    pub fn get_duration(&mut self) -> Result<f64, String> {
+        let val = self.get_property("duration")?;
+        val.as_f64().ok_or("duration not a number".into())
+    }
+}
+
+impl Drop for Mpv {
+    fn drop(&mut self) {
+        self.stop();
+    }
+}