From 701dfd5694e7795612e8fa1606e5ac15674b0c03 Mon Sep 17 00:00:00 2001
From: Geoffrey McRae <geoff@hostfission.com>
Date: Sat, 16 Jan 2021 21:17:35 +1100
Subject: [PATCH] [client] mouse: do not grab the pointer if the platform has
 no warp

Platforms such as Wayland have no abillity to warp the cursor, as such
can not operate in an always relative mode. This property allows
platforms to report the lack of warp support and prevent LG from
grabbing the pointer.
---
 client/include/interface/displayserver.h | 20 ++++++++++++++++++--
 client/src/main.c                        | 11 +++++++++--
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/client/include/interface/displayserver.h b/client/include/interface/displayserver.h
index 7146cc7d..62ae68f1 100644
--- a/client/include/interface/displayserver.h
+++ b/client/include/interface/displayserver.h
@@ -38,7 +38,19 @@ LG_ClipboardData;
 
 typedef enum LG_DSProperty
 {
-  LG_DS_MAX_MULTISAMPLE // data type is `int`
+  /**
+   * returns the maximum number of samples supported
+   * if not implemented LG assumes no multisample support
+   * return data type: int
+   */
+  LG_DS_MAX_MULTISAMPLE,
+
+  /**
+   * returns if the platform is warp capable
+   * if not implemented LG assumes that the platform is warp capable
+   * return data type: bool
+   */
+  LG_DS_WARP_SUPPORT,
 }
 LG_DSProperty;
 
@@ -64,7 +76,11 @@ struct LG_DisplayServerOps
   /* final free */
   void (*free)();
 
-  /* return a system specific property, returns false if unsupported or failure */
+  /*
+   * return a system specific property, returns false if unsupported or failure
+   * if the platform does not support/implement the requested property the value
+   * of `ret` must not be altered.
+   */
   bool (*getProp)(LG_DSProperty prop, void * ret);
 
   /* event filter, return true if the event has been handled */
diff --git a/client/src/main.c b/client/src/main.c
index 300a88e5..43f68d17 100644
--- a/client/src/main.c
+++ b/client/src/main.c
@@ -915,6 +915,11 @@ static void setCursorInView(bool enable)
   if (enable && !g_state.focused)
     return;
 
+  /* if the display server does not support warp, then we can not operate in
+   * always relative mode and we should not grab the pointer */
+  bool warpSupport = true;
+  app_getProp(LG_DS_WARP_SUPPORT, &warpSupport);
+
   g_cursor.inView = enable;
   g_cursor.draw   = params.alwaysShowCursor ? true : enable;
   g_cursor.redraw = true;
@@ -926,14 +931,16 @@ static void setCursorInView(bool enable)
     if (params.hideMouse)
       SDL_ShowCursor(SDL_DISABLE);
 
-    g_state.ds->grabPointer();
+    if (warpSupport)
+      g_state.ds->grabPointer();
   }
   else
   {
     if (params.hideMouse)
       SDL_ShowCursor(SDL_ENABLE);
 
-    g_state.ds->ungrabPointer();
+    if (warpSupport)
+      g_state.ds->ungrabPointer();
   }
 }