From b301c5b8fe23ce76fc52cde8272d1ea2827249b9 Mon Sep 17 00:00:00 2001
From: Jason Lee <huacnlee@gmail.com>
Date: Sun, 11 Aug 2024 21:12:29 +0800
Subject: [PATCH] Optimize and simplify the BlinkCursor. (#133)

---
 crates/ui/src/input/blink_cursor.rs | 53 +++++++++--------------------
 crates/ui/src/input/input.rs        |  2 +-
 crates/ui/src/input/otp_input.rs    |  2 +-
 3 files changed, 19 insertions(+), 38 deletions(-)

diff --git a/crates/ui/src/input/blink_cursor.rs b/crates/ui/src/input/blink_cursor.rs
index c1aaae35..3f8a3e6b 100644
--- a/crates/ui/src/input/blink_cursor.rs
+++ b/crates/ui/src/input/blink_cursor.rs
@@ -2,69 +2,57 @@ use std::time::Duration;
 
 use gpui::{ModelContext, Timer};
 
+static INTERVAL: Duration = Duration::from_millis(500);
+static PAUSE_DELAY: Duration = Duration::from_millis(300);
+
 /// To manage the Input cursor blinking.
 ///
 /// It will start blinking with a interval of 500ms.
 /// Every loop will notify the view to update the `visible`, and Input will observe this update to touch repaint.
 ///
 /// The input painter will check if this in visible state, then it will draw the cursor.
-pub struct BlinkCursor {
-    interval: Duration,
-    blink_epoch: usize,
+pub(crate) struct BlinkCursor {
     visible: bool,
     paused: bool,
-    started: bool,
+    epoch: usize,
 }
 
 impl BlinkCursor {
-    pub fn new(_cx: &mut ModelContext<Self>) -> Self {
+    pub fn new() -> Self {
         Self {
-            interval: Duration::from_millis(500),
             visible: false,
             paused: false,
-            started: false,
-            blink_epoch: 0,
+            epoch: 0,
         }
     }
 
     /// Start the blinking
     pub fn start(&mut self, cx: &mut ModelContext<Self>) {
-        if self.started {
-            return;
-        }
-
-        self.started = true;
-        self.blink(self.blink_epoch, cx);
+        self.blink(self.epoch, cx);
     }
 
     pub fn stop(&mut self, cx: &mut ModelContext<Self>) {
-        self.started = false;
+        self.epoch = 0;
         cx.notify();
     }
 
     fn next_epoch(&mut self) -> usize {
-        self.blink_epoch += 1;
-        self.blink_epoch
+        self.epoch += 1;
+        self.epoch
     }
 
     fn blink(&mut self, epoch: usize, cx: &mut ModelContext<Self>) {
-        if self.paused || !self.started {
-            return;
-        }
-
-        if epoch != self.blink_epoch {
+        if self.paused || epoch != self.epoch {
             return;
         }
 
         self.visible = !self.visible;
         cx.notify();
 
-        let epoch = self.next_epoch();
-
         // Schedule the next blink
-        let interval = self.interval;
+        let epoch = self.next_epoch();
         cx.spawn(|this, mut cx| async move {
-            Timer::after(interval).await;
+            Timer::after(INTERVAL).await;
             if let Some(this) = this.upgrade() {
                 this.update(&mut cx, |this, cx| this.blink(epoch, cx)).ok();
             }
@@ -74,28 +62,21 @@ impl BlinkCursor {
 
     pub fn visible(&self) -> bool {
         // Keep showing the cursor if paused
-        if self.paused {
-            return true;
-        }
-        self.visible
+        self.paused || self.visible
     }
 
     /// Pause the blinking, and delay 500ms to resume the blinking.
     pub fn pause(&mut self, cx: &mut ModelContext<Self>) {
         self.paused = true;
-        self.next_epoch();
         cx.notify();
 
-        let epoch = self.next_epoch();
         // delay 500ms to start the blinking
+        let epoch = self.next_epoch();
         cx.spawn(|this, mut cx| async move {
-            Timer::after(Duration::from_secs_f64(0.5)).await;
+            Timer::after(PAUSE_DELAY).await;
 
             if let Some(this) = this.upgrade() {
                 this.update(&mut cx, |this, cx| {
-                    if epoch != this.blink_epoch {
-                        return;
-                    }
                     this.paused = false;
                     this.blink(epoch, cx);
                 })
diff --git a/crates/ui/src/input/input.rs b/crates/ui/src/input/input.rs
index 6815fed7..4618fa87 100644
--- a/crates/ui/src/input/input.rs
+++ b/crates/ui/src/input/input.rs
@@ -137,7 +137,7 @@ impl EventEmitter<InputEvent> for TextInput {}
 impl TextInput {
     pub fn new(cx: &mut ViewContext<Self>) -> Self {
         let focus_handle = cx.focus_handle();
-        let blink_cursor = cx.new_model(|cx| BlinkCursor::new(cx));
+        let blink_cursor = cx.new_model(|_| BlinkCursor::new());
         let history = History::new();
         let input = Self {
             focus_handle: focus_handle.clone(),
diff --git a/crates/ui/src/input/otp_input.rs b/crates/ui/src/input/otp_input.rs
index 4222cddd..5b6b75bb 100644
--- a/crates/ui/src/input/otp_input.rs
+++ b/crates/ui/src/input/otp_input.rs
@@ -26,7 +26,7 @@ pub struct OtpInput {
 impl OtpInput {
     pub fn new(length: usize, cx: &mut ViewContext<Self>) -> Self {
         let focus_handle = cx.focus_handle();
-        let blink_cursor = cx.new_model(|cx| BlinkCursor::new(cx));
+        let blink_cursor = cx.new_model(|_| BlinkCursor::new());
         let input = Self {
             focus_handle: focus_handle.clone(),
             length,