Add keypress_delay_ms to workaround #179 (#191)

Close #179

README.md

@@ -295,6 +295,12 @@ keymap:
       CapsLock-l: Right
 ```
 
+### keypress_delay_ms
+
+Some applications have trouble understanding synthesized key events, especially on
+Wayland. `keypress_delay_ms` can be used to workaround the issue.
+See [#179](https://github.com/k0kubun/xremap/issues/179) for the detail.
+
 ## License
 
 `xremap` is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).

src/config/mod.rs

@@ -36,6 +36,8 @@ pub struct Config {
     pub default_mode: String,
     #[serde(deserialize_with = "deserialize_virtual_modifiers", default = "Vec::new")]
     pub virtual_modifiers: Vec<Key>,
+    #[serde(default)]
+    pub keypress_delay_ms: u64,
 
     // Internals
     #[serde(skip)]

src/event_handler.rs

@@ -17,7 +17,8 @@ use nix::sys::timerfd::{Expiration, TimerFd, TimerSetTimeFlags};
 use std::collections::{HashMap, HashSet};
 use std::error::Error;
 use std::process::{Command, Stdio};
-use std::time::Instant;
+use std::thread;
+use std::time::{Duration, Instant};
 
 pub struct EventHandler {
     // Device to emit events
@@ -47,10 +48,11 @@ pub struct EventHandler {
     mark_set: bool,
     // { escape_next_key: true }
     escape_next_key: bool,
+    keypress_delay: Duration,
 }
 
 impl EventHandler {
-    pub fn new(device: VirtualDevice, timer: TimerFd, mode: &str) -> EventHandler {
+    pub fn new(device: VirtualDevice, timer: TimerFd, mode: &str, keypress_delay: Duration) -> EventHandler {
         EventHandler {
             device,
             modifiers: HashSet::new(),
@@ -66,6 +68,7 @@ impl EventHandler {
             mode: mode.to_string(),
             mark_set: false,
             escape_next_key: false,
+            keypress_delay,
         }
     }
 
@@ -345,6 +348,8 @@ impl EventHandler {
         self.send_key(&key_press.key, PRESS)?;
         self.send_key(&key_press.key, RELEASE)?;
 
+        thread::sleep(self.keypress_delay);
+
         // Resurrect the original modifiers
         self.send_keys(&missing_modifiers, RELEASE)?;
         self.send_keys(&extra_modifiers, PRESS)?;

src/main.rs

@@ -16,6 +16,7 @@ use std::collections::HashMap;
 use std::io::stdout;
 use std::os::unix::io::{AsRawFd, RawFd};
 use std::path::{Path, PathBuf};
+use std::time::Duration;
 
 mod client;
 mod config;
@@ -110,7 +111,8 @@ fn main() -> anyhow::Result<()> {
     };
     let timer = TimerFd::new(ClockId::CLOCK_MONOTONIC, TimerFlags::empty())?;
     let timer_fd = timer.as_raw_fd();
-    let mut handler = EventHandler::new(output_device, timer, &config.default_mode);
+    let delay = Duration::from_millis(config.keypress_delay_ms);
+    let mut handler = EventHandler::new(output_device, timer, &config.default_mode, delay);
     let mut input_devices = match get_input_devices(&device_filter, &ignore_filter, mouse, watch_devices) {
         Ok(input_devices) => input_devices,
         Err(e) => bail!("Failed to prepare input devices: {}", e),