input: support explicit modes (timeout, sticky) for drag-lock

Cargo.toml

@@ -73,7 +73,7 @@ fastrand = "2.4.1"
 futures-util = { version = "0.3.32", default-features = false, features = ["std", "io"] }
 git-version = "0.3.9"
 glam = "0.32.1"
-input = { version = "0.10.0", features = ["libinput_1_21"] }
+input = { version = "0.10.0", features = ["libinput_1_27"] }
 keyframe = { version = "1.1.1", default-features = false }
 libc = "0.2.185"
 libdisplay-info = "0.3.0"

docs/wiki/Configuration:-Input.md

@@ -32,7 +32,8 @@ input {
         // dwt
         // dwtp
         // drag false
-        // drag-lock
+        // drag-lock           // timeout mode
+        // drag-lock "sticky"  // sticky mode
         natural-scroll
         // accel-speed 0.2
         // accel-profile "flat"
@@ -247,7 +248,10 @@ Settings specific to `touchpad`s:
 - `dwt`: disable-when-typing.
 - `dwtp`: disable-when-trackpointing.
 - `drag`: <sup>Since: 25.05</sup> can be `true` or `false`, controls if tap-and-drag is enabled.
-- `drag-lock`: <sup>Since: 25.02</sup> if set, lifting the finger off for a short time while dragging will not drop the dragged item. See the [libinput documentation](https://wayland.freedesktop.org/libinput/doc/latest/tapping.html#tap-and-drag).
+- `drag-lock`: <sup>Since: 25.02, explicit modes next release</sup> controls drag lock behavior. Can be set as a flag (`drag-lock`), or with an explicit mode (`drag-lock "timeout"` or `drag-lock "sticky"`).
+  - `"timeout"` (default when set as a flag): lifting the finger off for a short time while dragging will not drop the dragged item.
+  - `"sticky"`: the drag continues until you tap again to release.
+  - See the [libinput documentation](https://wayland.freedesktop.org/libinput/doc/latest/tapping.html#tap-and-drag).
 - `tap-button-map`: can be `left-right-middle` or `left-middle-right`, controls which button corresponds to a two-finger tap and a three-finger tap.
 - `click-method`: can be `button-areas` or `clickfinger`, changes the [click method](https://wayland.freedesktop.org/libinput/doc/latest/clickpad-softbuttons.html).
 - `disabled-on-external-mouse`: do not send events while external pointer device is plugged in.

niri-config/src/input.rs

@@ -195,8 +195,8 @@ pub struct Touchpad {
     pub dwtp: bool,
     #[knuffel(child, unwrap(argument))]
     pub drag: Option<bool>,
-    #[knuffel(child)]
-    pub drag_lock: bool,
+    #[knuffel(child, unwrap(argument, str, default))]
+    pub drag_lock: Option<DragLock>,
     #[knuffel(child)]
     pub natural_scroll: bool,
     #[knuffel(child, unwrap(argument, str))]
@@ -291,6 +291,26 @@ pub struct Trackball {
     pub middle_emulation: bool,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub enum DragLock {
+    #[default]
+    Timeout,
+    Sticky,
+}
+
+impl FromStr for DragLock {
+    type Err = miette::Error;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "timeout" => Ok(DragLock::Timeout),
+            "sticky" => Ok(DragLock::Sticky),
+            _ => Err(miette!(
+                r#"invalid drag-lock value, expected \"timeout\" or \"sticky\""#
+            )),
+        }
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum ClickMethod {
     Clickfinger,

niri-config/src/lib.rs

@@ -856,7 +856,7 @@ mod tests {
                 window-open { off; }
 
                 window-close {
-                    curve "cubic-bezier" 0.05 0.7 0.1 1  
+                    curve "cubic-bezier" 0.05 0.7 0.1 1
                 }
 
                 recent-windows-close {
@@ -993,7 +993,7 @@ mod tests {
                     drag: Some(
                         true,
                     ),
-                    drag_lock: false,
+                    drag_lock: None,
                     natural_scroll: false,
                     click_method: Some(
                         Clickfinger,

resources/default-config.kdl

@@ -34,7 +34,8 @@ input {
         // dwt
         // dwtp
         // drag false
-        // drag-lock
+        // drag-lock           // timeout mode
+        // drag-lock "sticky"  // sticky mode
         natural-scroll
         // accel-speed 0.2
         // accel-profile "flat"

src/input/mod.rs

@@ -4686,10 +4686,10 @@ pub fn apply_libinput_settings(config: &niri_config::Input, device: &mut input::
         let _ = device.config_tap_set_enabled(c.tap);
         let _ = device.config_dwt_set_enabled(c.dwt);
         let _ = device.config_dwtp_set_enabled(c.dwtp);
-        let _ = device.config_tap_set_drag_lock_enabled(if c.drag_lock {
-            input::DragLockState::EnabledTimeout
-        } else {
-            input::DragLockState::Disabled
+        let _ = device.config_tap_set_drag_lock_enabled(match c.drag_lock {
+            Some(niri_config::input::DragLock::Timeout) => input::DragLockState::EnabledTimeout,
+            Some(niri_config::input::DragLock::Sticky) => input::DragLockState::EnabledSticky,
+            None => input::DragLockState::Disabled,
         });
         let _ = device.config_scroll_set_natural_scroll_enabled(c.natural_scroll);
         let _ = device.config_accel_set_speed(c.accel_speed.0);