From 86bdd71fec865937604f82a9cf428c8f329907a6 Mon Sep 17 00:00:00 2001
From: Prabir Pradhan <prabirmsp@google.com>
Date: Fri, 6 Aug 2021 13:42:56 +0000
Subject: [PATCH] Use sequence numbers to synchronize enabling Pointer Capture
 (2/2)

InputReader only processes configuration change from its main thread.
This means that if there is more than one Pointer Capture change
request when the thread is busy or sleeping, it will only process the
latest one. To ensure requests to enable Pointer Capture are synchronized
with Dispatcher, we must use sequence numbers.

Requests to enable Pointer Capture have a sequence number. Requests to
disable Pointer Capture do not have a value.

Bug: 195312888
Test: atest inputflinger_tests
Test: manual with GeforceNow app, see bug.
Merged-In: I52eb7493012d476664de45d2913ceefa23466a7c
Change-Id: I52eb7493012d476664de45d2913ceefa23466a7c
---
 ...droid_server_input_InputManagerService.cpp | 21 ++++++++++---------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/services/core/jni/com_android_server_input_InputManagerService.cpp b/services/core/jni/com_android_server_input_InputManagerService.cpp
index a94ad4ad7ef22..bb9740b60f782 100644
--- a/services/core/jni/com_android_server_input_InputManagerService.cpp
+++ b/services/core/jni/com_android_server_input_InputManagerService.cpp
@@ -337,7 +337,7 @@ public:
     void pokeUserActivity(nsecs_t eventTime, int32_t eventType, int32_t displayId) override;
     bool checkInjectEventsPermissionNonReentrant(int32_t injectorPid, int32_t injectorUid) override;
     void onPointerDownOutsideFocus(const sp<IBinder>& touchedToken) override;
-    void setPointerCapture(bool enabled) override;
+    void setPointerCapture(const PointerCaptureRequest& request) override;
     void notifyDropWindow(const sp<IBinder>& token, float x, float y) override;
 
     /* --- PointerControllerPolicyInterface implementation --- */
@@ -372,8 +372,8 @@ private:
         // Show touches feature enable/disable.
         bool showTouches;
 
-        // Pointer capture feature enable/disable.
-        bool pointerCapture;
+        // The latest request to enable or disable Pointer Capture.
+        PointerCaptureRequest pointerCaptureRequest;
 
         // Sprite controller singleton, created on first use.
         sp<SpriteController> spriteController;
@@ -417,7 +417,6 @@ NativeInputManager::NativeInputManager(jobject contextObj,
         mLocked.pointerSpeed = 0;
         mLocked.pointerGesturesEnabled = true;
         mLocked.showTouches = false;
-        mLocked.pointerCapture = false;
         mLocked.pointerDisplayId = ADISPLAY_ID_DEFAULT;
     }
     mInteractive = true;
@@ -446,7 +445,9 @@ void NativeInputManager::dump(std::string& dump) {
         dump += StringPrintf(INDENT "Pointer Gestures Enabled: %s\n",
                 toString(mLocked.pointerGesturesEnabled));
         dump += StringPrintf(INDENT "Show Touches: %s\n", toString(mLocked.showTouches));
-        dump += StringPrintf(INDENT "Pointer Capture Enabled: %s\n", toString(mLocked.pointerCapture));
+        dump += StringPrintf(INDENT "Pointer Capture: %s, seq=%" PRIu32 "\n",
+                             mLocked.pointerCaptureRequest.enable ? "Enabled" : "Disabled",
+                             mLocked.pointerCaptureRequest.seq);
     }
     dump += "\n";
 
@@ -634,7 +635,7 @@ void NativeInputManager::getReaderConfiguration(InputReaderConfiguration* outCon
 
         outConfig->showTouches = mLocked.showTouches;
 
-        outConfig->pointerCapture = mLocked.pointerCapture;
+        outConfig->pointerCaptureRequest = mLocked.pointerCaptureRequest;
 
         outConfig->setDisplayViewports(mLocked.viewports);
 
@@ -1383,16 +1384,16 @@ void NativeInputManager::onPointerDownOutsideFocus(const sp<IBinder>& touchedTok
     checkAndClearExceptionFromCallback(env, "onPointerDownOutsideFocus");
 }
 
-void NativeInputManager::setPointerCapture(bool enabled) {
+void NativeInputManager::setPointerCapture(const PointerCaptureRequest& request) {
     { // acquire lock
         AutoMutex _l(mLock);
 
-        if (mLocked.pointerCapture == enabled) {
+        if (mLocked.pointerCaptureRequest == request) {
             return;
         }
 
-        ALOGV("%s pointer capture.", enabled ? "Enabling" : "Disabling");
-        mLocked.pointerCapture = enabled;
+        ALOGV("%s pointer capture.", request.enable ? "Enabling" : "Disabling");
+        mLocked.pointerCaptureRequest = request;
     } // release lock
 
     mInputManager->getReader()->requestRefreshConfiguration(