From 692bbdb3a8ec16753ba37b65bba2b1b09eb3dad7 Mon Sep 17 00:00:00 2001
From: Prabir Pradhan <prabirmsp@google.com>
Date: Fri, 24 Feb 2023 01:52:13 +0000
Subject: Get mouse cursor position from PointerController instead of WM

PointerController is the source of truth of the mouse cursor position.
When the VirtualDevice APIs queried the cursor position, we were
previously getting the position from WM. WM's values only update once
system_server's global monitor has processed the input event, which
leads us into a race condition.

Remove the race consition by querying the mouse cursor position directly
from PointerController.

Bug: 266687189
Test: atest VirtualMouseTest
Change-Id: Id0e0e20a0d547f969d3a27d43fdfdca34d0fa7c0
---
 libs/input/PointerController.cpp | 39 +++++++++++++++++++++++++++------------
 1 file changed, 27 insertions(+), 12 deletions(-)

(limited to 'libs/input/PointerController.cpp')

diff --git a/libs/input/PointerController.cpp b/libs/input/PointerController.cpp
index fedf58d7c6d0..e748c692743d 100644
--- a/libs/input/PointerController.cpp
+++ b/libs/input/PointerController.cpp
@@ -262,19 +262,34 @@ void PointerController::reloadPointerResources() {
 }
 
 void PointerController::setDisplayViewport(const DisplayViewport& viewport) {
-    std::scoped_lock lock(getLock());
+    struct PointerDisplayChangeArgs {
+        int32_t displayId;
+        float x, y;
+    };
+    std::optional<PointerDisplayChangeArgs> pointerDisplayChanged;
 
-    bool getAdditionalMouseResources = false;
-    if (mLocked.presentation == PointerController::Presentation::POINTER ||
-        mLocked.presentation == PointerController::Presentation::STYLUS_HOVER) {
-        getAdditionalMouseResources = true;
-    }
-    mCursorController.setDisplayViewport(viewport, getAdditionalMouseResources);
-    if (viewport.displayId != mLocked.pointerDisplayId) {
-        float xPos, yPos;
-        mCursorController.getPosition(&xPos, &yPos);
-        mContext.getPolicy()->onPointerDisplayIdChanged(viewport.displayId, xPos, yPos);
-        mLocked.pointerDisplayId = viewport.displayId;
+    { // acquire lock
+        std::scoped_lock lock(getLock());
+
+        bool getAdditionalMouseResources = false;
+        if (mLocked.presentation == PointerController::Presentation::POINTER ||
+            mLocked.presentation == PointerController::Presentation::STYLUS_HOVER) {
+            getAdditionalMouseResources = true;
+        }
+        mCursorController.setDisplayViewport(viewport, getAdditionalMouseResources);
+        if (viewport.displayId != mLocked.pointerDisplayId) {
+            float xPos, yPos;
+            mCursorController.getPosition(&xPos, &yPos);
+            mLocked.pointerDisplayId = viewport.displayId;
+            pointerDisplayChanged = {viewport.displayId, xPos, yPos};
+        }
+    } // release lock
+
+    if (pointerDisplayChanged) {
+        // Notify the policy without holding the pointer controller lock.
+        mContext.getPolicy()->onPointerDisplayIdChanged(pointerDisplayChanged->displayId,
+                                                        pointerDisplayChanged->x,
+                                                        pointerDisplayChanged->y);
     }
 }
 
-- 
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