[fix] restore remote cursors on Windows without a physical mouse

2026-10-21 03:40:40 +08:00 · 2026-09-16 22:20:36 +08:00
parent 1d9242515a
commit d9116200fe
13 changed files with 323 additions and 48 deletions
@@ -0,0 +1,77 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-09-16
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _CURSOR_PRESENTATION_H_
+#define _CURSOR_PRESENTATION_H_
+
+#include <remote_action.h>
+
+#include <cstdint>
+#include <optional>
+
+namespace crossdesk {
+
+// All times use one monotonic millisecond clock. The owning session's cursor
+// mutex protects this policy from the transport and UI threads.
+class CursorPresentation {
+ public:
+  static constexpr uint64_t kStateTimeoutMs = 1500;  // Three 500ms heartbeats.
+  static constexpr uint64_t kInputActivityMs = 1500;
+
+  void Observe(const CursorState& state, uint64_t now) {
+    if (state.render_mode == CursorRenderMode::unknown) {
+      // Repeated unavailable samples must not extend the recovery deadline.
+      if (!sample_unavailable_) stale_at_ = now + kStateTimeoutMs;
+      sample_unavailable_ = true;
+      return;
+    }
+    sample_unavailable_ = false;
+    stale_at_ = now + kStateTimeoutMs;
+    const bool separate =
+        state.render_mode == CursorRenderMode::separate ||
+        (state.render_mode == CursorRenderMode::legacy && state.visible);
+    // Old senders cannot distinguish embedded from hidden. Only explicit
+    // metadata from a new sender can establish the no-device compatibility
+    // case.
+    no_device_ = state.render_mode == CursorRenderMode::hidden &&
+                 state.hidden_reason == CursorHiddenReason::no_pointing_device;
+    held_shape_ = separate ? state.shape : RemoteCursorShape::none;
+    if (held_shape_ != RemoteCursorShape::none) {
+      last_visible_shape_ = held_shape_;
+    }
+    if (!no_device_) fallback_engaged_ = false;
+  }
+
+  void NoteInput(uint64_t now) { last_input_ = now; }
+
+  RemoteCursorShape Resolve(uint64_t now) {
+    if (!stale_at_) return RemoteCursorShape::default_cursor;
+
+    const bool recent_input =
+        last_input_ && now - *last_input_ < kInputActivityMs;
+    const bool can_recover =
+        now >= *stale_at_ || (!sample_unavailable_ && no_device_);
+    if (can_recover && recent_input) {
+      fallback_engaged_ = true;
+    }
+    // Once needed, retain the locator while idle until a good non-compatibility
+    // sample arrives. Otherwise it would blink off whenever input pauses.
+    return fallback_engaged_ ? last_visible_shape_ : held_shape_;
+  }
+
+ private:
+  bool sample_unavailable_ = false;
+  bool no_device_ = false;
+  bool fallback_engaged_ = false;
+  std::optional<uint64_t> stale_at_;
+  std::optional<uint64_t> last_input_;
+  RemoteCursorShape held_shape_ = RemoteCursorShape::default_cursor;
+  RemoteCursorShape last_visible_shape_ = RemoteCursorShape::default_cursor;
+};
+
+}  // namespace crossdesk
+
+#endif