Store pointers per-device

Previously, input dispatcher assumed that a single input device is
active. However, we are trying to add multi-device support.

In this CL, store the pointers inside touched windows on a per-device
basis. This CL should not cause any behaviour changes. We expect there
to be a single device active at a time still.

Bug: 211379801
Bug: 281806933
Test: m inputflinger_tests && $ANDROID_HOST_OUT/nativetest64/inputflinger_tests/inputflinger_tests
Change-Id: I73fc4adcf306bb49e153f3daeed68753e0632c86
Signed-off-by: Siarhei Vishniakou <svv@google.com>
diff --git a/include/input/PrintTools.h b/include/input/PrintTools.h
index 0ca6fa3..0e3fbb1 100644
--- a/include/input/PrintTools.h
+++ b/include/input/PrintTools.h
@@ -27,6 +27,9 @@
 
 template <size_t N>
 std::string bitsetToString(const std::bitset<N>& bitset) {
+    if (bitset.none()) {
+        return "<none>";
+    }
     return bitset.to_string();
 }
 
diff --git a/services/inputflinger/dispatcher/InputDispatcher.cpp b/services/inputflinger/dispatcher/InputDispatcher.cpp
index 6f2464b..d91fe4c 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.cpp
+++ b/services/inputflinger/dispatcher/InputDispatcher.cpp
@@ -654,7 +654,6 @@
             TouchedWindow touchedWindow;
             touchedWindow.windowHandle = oldWindow;
             touchedWindow.targetFlags = InputTarget::Flags::DISPATCH_AS_HOVER_EXIT;
-            touchedWindow.pointerIds.set(pointerId);
             out.push_back(touchedWindow);
         }
     }
@@ -673,7 +672,7 @@
             }
             touchedWindow.targetFlags = InputTarget::Flags::DISPATCH_AS_IS;
         }
-        touchedWindow.pointerIds.set(pointerId);
+        touchedWindow.addHoveringPointer(entry.deviceId, pointerId);
         if (canReceiveForegroundTouches(*newWindow->getInfo())) {
             touchedWindow.targetFlags |= InputTarget::Flags::FOREGROUND;
         }
@@ -2195,8 +2194,8 @@
 /**
  * In general, touch should be always split between windows. Some exceptions:
  * 1. Don't split touch is if we have an active pointer down, and a new pointer is going down that's
- * from the same device, *and* the window that's receiving the current pointer does not support
- * split touch.
+ *    from the same device, *and* the window that's receiving the current pointer does not support
+ *    split touch.
  * 2. Don't split mouse events
  */
 bool InputDispatcher::shouldSplitTouch(const TouchState& touchState,
@@ -2221,7 +2220,8 @@
 
         // Eventually, touchedWindow will contain the deviceId of each pointer that's currently
         // being sent there. For now, use deviceId from touch state.
-        if (entry.deviceId == touchState.deviceId && touchedWindow.pointerIds.any()) {
+        if (entry.deviceId == touchState.deviceId &&
+            touchedWindow.hasTouchingPointers(entry.deviceId)) {
             return false;
         }
     }
@@ -2404,7 +2404,7 @@
             // still add a window to the touch state. We should avoid doing that, but some of the
             // later checks ("at least one foreground window") rely on this in order to dispatch
             // the event properly, so that needs to be updated, possibly by looking at InputTargets.
-            tempTouchState.addOrUpdateWindow(windowHandle, targetFlags, pointerIds,
+            tempTouchState.addOrUpdateWindow(windowHandle, targetFlags, entry.deviceId, pointerIds,
                                              isDownOrPointerDown
                                                      ? std::make_optional(entry.eventTime)
                                                      : std::nullopt);
@@ -2428,8 +2428,8 @@
                         if (isSplit) {
                             wallpaperFlags |= InputTarget::Flags::SPLIT;
                         }
-                        tempTouchState.addOrUpdateWindow(wallpaper, wallpaperFlags, pointerIds,
-                                                         entry.eventTime);
+                        tempTouchState.addOrUpdateWindow(wallpaper, wallpaperFlags, entry.deviceId,
+                                                         pointerIds, entry.eventTime);
                     }
                 }
             }
@@ -2440,12 +2440,12 @@
         // which is a specific behaviour that we want.
         const int32_t pointerId = entry.pointerProperties[pointerIndex].id;
         for (TouchedWindow& touchedWindow : tempTouchState.windows) {
-            if (touchedWindow.pointerIds.test(pointerId) &&
-                touchedWindow.pilferedPointerIds.count() > 0) {
+            if (touchedWindow.hasTouchingPointer(entry.deviceId, pointerId) &&
+                touchedWindow.hasPilferingPointers(entry.deviceId)) {
                 // This window is already pilfering some pointers, and this new pointer is also
                 // going to it. Therefore, take over this pointer and don't give it to anyone
                 // else.
-                touchedWindow.pilferedPointerIds.set(pointerId);
+                touchedWindow.addPilferingPointer(entry.deviceId, pointerId);
             }
         }
 
@@ -2517,7 +2517,7 @@
                         tempTouchState.getTouchedWindow(oldTouchedWindowHandle);
                 addWindowTargetLocked(oldTouchedWindowHandle,
                                       InputTarget::Flags::DISPATCH_AS_SLIPPERY_EXIT, pointerIds,
-                                      touchedWindow.firstDownTimeInTarget, targets);
+                                      touchedWindow.getDownTimeInTarget(entry.deviceId), targets);
 
                 // Make a slippery entrance into the new window.
                 if (newTouchedWindowHandle->getInfo()->supportsSplitTouch()) {
@@ -2538,13 +2538,14 @@
                     targetFlags |= InputTarget::Flags::WINDOW_IS_PARTIALLY_OBSCURED;
                 }
 
-                tempTouchState.addOrUpdateWindow(newTouchedWindowHandle, targetFlags, pointerIds,
-                                                 entry.eventTime);
+                tempTouchState.addOrUpdateWindow(newTouchedWindowHandle, targetFlags,
+                                                 entry.deviceId, pointerIds, entry.eventTime);
 
                 // Check if the wallpaper window should deliver the corresponding event.
                 slipWallpaperTouch(targetFlags, oldTouchedWindowHandle, newTouchedWindowHandle,
-                                   tempTouchState, pointerId, targets);
-                tempTouchState.removeTouchedPointerFromWindow(pointerId, oldTouchedWindowHandle);
+                                   tempTouchState, entry.deviceId, pointerId, targets);
+                tempTouchState.removeTouchingPointerFromWindow(entry.deviceId, pointerId,
+                                                               oldTouchedWindowHandle);
             }
         }
 
@@ -2558,7 +2559,8 @@
                 if (mDragState && mDragState->dragWindow == touchedWindow.windowHandle) {
                     continue;
                 }
-                touchedWindow.pointerIds.set(entry.pointerProperties[pointerIndex].id);
+                touchedWindow.addTouchingPointer(entry.deviceId,
+                                                 entry.pointerProperties[pointerIndex].id);
             }
         }
     }
@@ -2570,7 +2572,7 @@
         for (const TouchedWindow& touchedWindow : hoveringWindows) {
             std::optional<InputTarget> target =
                     createInputTargetLocked(touchedWindow.windowHandle, touchedWindow.targetFlags,
-                                            touchedWindow.firstDownTimeInTarget);
+                                            touchedWindow.getDownTimeInTarget(entry.deviceId));
             if (!target) {
                 continue;
             }
@@ -2627,15 +2629,16 @@
 
     // Output targets from the touch state.
     for (const TouchedWindow& touchedWindow : tempTouchState.windows) {
-        if (touchedWindow.pointerIds.none() && !touchedWindow.hasHoveringPointers(entry.deviceId)) {
+        if (!touchedWindow.hasTouchingPointers(entry.deviceId) &&
+            !touchedWindow.hasHoveringPointers(entry.deviceId)) {
             // Windows with hovering pointers are getting persisted inside TouchState.
             // Do not send this event to those windows.
             continue;
         }
 
         addWindowTargetLocked(touchedWindow.windowHandle, touchedWindow.targetFlags,
-                              touchedWindow.pointerIds, touchedWindow.firstDownTimeInTarget,
-                              targets);
+                              touchedWindow.getTouchingPointers(entry.deviceId),
+                              touchedWindow.getDownTimeInTarget(entry.deviceId), targets);
     }
 
     // During targeted injection, only allow owned targets to receive events
@@ -2694,7 +2697,7 @@
         }
     } else if (maskedAction == AMOTION_EVENT_ACTION_UP) {
         // Pointer went up.
-        tempTouchState.removeTouchedPointer(entry.pointerProperties[0].id);
+        tempTouchState.removeTouchingPointer(entry.deviceId, entry.pointerProperties[0].id);
     } else if (maskedAction == AMOTION_EVENT_ACTION_CANCEL) {
         // All pointers up or canceled.
         tempTouchState.reset();
@@ -2711,8 +2714,8 @@
 
         for (size_t i = 0; i < tempTouchState.windows.size();) {
             TouchedWindow& touchedWindow = tempTouchState.windows[i];
-            touchedWindow.pointerIds.reset(pointerId);
-            if (touchedWindow.pointerIds.none()) {
+            touchedWindow.removeTouchingPointer(entry.deviceId, pointerId);
+            if (!touchedWindow.hasTouchingPointers(entry.deviceId)) {
                 tempTouchState.windows.erase(tempTouchState.windows.begin() + i);
                 continue;
             }
@@ -5451,14 +5454,22 @@
 
         // Find the target touch state and touched window by fromToken.
         auto [state, touchedWindow, displayId] = findTouchStateWindowAndDisplayLocked(fromToken);
+
         if (state == nullptr || touchedWindow == nullptr) {
-            ALOGD("Focus transfer failed because from window is not being touched.");
+            ALOGD("Touch transfer failed because from window is not being touched.");
             return false;
         }
+        std::set<int32_t> deviceIds = touchedWindow->getTouchingDeviceIds();
+        if (deviceIds.size() != 1) {
+            LOG(DEBUG) << "Can't transfer touch. Currently touching devices: " << dumpSet(deviceIds)
+                       << " for window: " << touchedWindow->dump();
+            return false;
+        }
+        const int32_t deviceId = *deviceIds.begin();
 
         sp<WindowInfoHandle> toWindowHandle = getWindowHandleLocked(toToken, displayId);
         if (toWindowHandle == nullptr) {
-            ALOGW("Cannot transfer focus because to window not found.");
+            ALOGW("Cannot transfer touch because to window not found.");
             return false;
         }
 
@@ -5470,7 +5481,7 @@
 
         // Erase old window.
         ftl::Flags<InputTarget::Flags> oldTargetFlags = touchedWindow->targetFlags;
-        std::bitset<MAX_POINTER_ID + 1> pointerIds = touchedWindow->pointerIds;
+        std::bitset<MAX_POINTER_ID + 1> pointerIds = touchedWindow->getTouchingPointers(deviceId);
         sp<WindowInfoHandle> fromWindowHandle = touchedWindow->windowHandle;
         state->removeWindowByToken(fromToken);
 
@@ -5481,7 +5492,8 @@
         if (canReceiveForegroundTouches(*toWindowHandle->getInfo())) {
             newTargetFlags |= InputTarget::Flags::FOREGROUND;
         }
-        state->addOrUpdateWindow(toWindowHandle, newTargetFlags, pointerIds, downTimeInTarget);
+        state->addOrUpdateWindow(toWindowHandle, newTargetFlags, deviceId, pointerIds,
+                                 downTimeInTarget);
 
         // Store the dragging window.
         if (isDragDrop) {
@@ -5500,16 +5512,15 @@
         std::shared_ptr<Connection> toConnection = getConnectionLocked(toToken);
         if (fromConnection != nullptr && toConnection != nullptr) {
             fromConnection->inputState.mergePointerStateTo(toConnection->inputState);
-            CancelationOptions
-                    options(CancelationOptions::Mode::CANCEL_POINTER_EVENTS,
-                            "transferring touch focus from this window to another window");
+            CancelationOptions options(CancelationOptions::Mode::CANCEL_POINTER_EVENTS,
+                                       "transferring touch from this window to another window");
             synthesizeCancelationEventsForConnectionLocked(fromConnection, options);
             synthesizePointerDownEventsForConnectionLocked(downTimeInTarget, toConnection,
                                                            newTargetFlags);
 
             // Check if the wallpaper window should deliver the corresponding event.
             transferWallpaperTouch(oldTargetFlags, newTargetFlags, fromWindowHandle, toWindowHandle,
-                                   *state, pointerIds);
+                                   *state, deviceId, pointerIds);
         }
     } // release lock
 
@@ -5993,20 +6004,28 @@
     }
 
     auto [statePtr, windowPtr, displayId] = findTouchStateWindowAndDisplayLocked(token);
-    if (statePtr == nullptr || windowPtr == nullptr || windowPtr->pointerIds.none()) {
+    if (statePtr == nullptr || windowPtr == nullptr) {
         ALOGW("Attempted to pilfer points from a channel without any on-going pointer streams."
               " Ignoring.");
         return BAD_VALUE;
     }
+    std::set<int32_t> deviceIds = windowPtr->getTouchingDeviceIds();
+    if (deviceIds.size() != 1) {
+        LOG(WARNING) << "Can't pilfer. Currently touching devices: " << dumpSet(deviceIds)
+                     << " in window: " << windowPtr->dump();
+        return BAD_VALUE;
+    }
+    const int32_t deviceId = *deviceIds.begin();
 
     TouchState& state = *statePtr;
     TouchedWindow& window = *windowPtr;
     // Send cancel events to all the input channels we're stealing from.
     CancelationOptions options(CancelationOptions::Mode::CANCEL_POINTER_EVENTS,
                                "input channel stole pointer stream");
-    options.deviceId = state.deviceId;
+    options.deviceId = deviceId;
     options.displayId = displayId;
-    options.pointerIds = window.pointerIds;
+    std::bitset<MAX_POINTER_ID + 1> pointerIds = window.getTouchingPointers(deviceId);
+    options.pointerIds = pointerIds;
     std::string canceledWindows;
     for (const TouchedWindow& w : state.windows) {
         const std::shared_ptr<InputChannel> channel =
@@ -6023,9 +6042,9 @@
 
     // Prevent the gesture from being sent to any other windows.
     // This only blocks relevant pointers to be sent to other windows
-    window.pilferedPointerIds |= window.pointerIds;
+    window.addPilferingPointers(deviceId, pointerIds);
 
-    state.cancelPointersForWindowsExcept(window.pointerIds, token);
+    state.cancelPointersForWindowsExcept(deviceId, pointerIds, token);
     return OK;
 }
 
@@ -6812,7 +6831,7 @@
 void InputDispatcher::slipWallpaperTouch(ftl::Flags<InputTarget::Flags> targetFlags,
                                          const sp<WindowInfoHandle>& oldWindowHandle,
                                          const sp<WindowInfoHandle>& newWindowHandle,
-                                         TouchState& state, int32_t pointerId,
+                                         TouchState& state, int32_t deviceId, int32_t pointerId,
                                          std::vector<InputTarget>& targets) const {
     std::bitset<MAX_POINTER_ID + 1> pointerIds;
     pointerIds.set(pointerId);
@@ -6834,8 +6853,8 @@
         addWindowTargetLocked(oldWallpaper,
                               oldTouchedWindow.targetFlags |
                                       InputTarget::Flags::DISPATCH_AS_SLIPPERY_EXIT,
-                              pointerIds, oldTouchedWindow.firstDownTimeInTarget, targets);
-        state.removeTouchedPointerFromWindow(pointerId, oldWallpaper);
+                              pointerIds, oldTouchedWindow.getDownTimeInTarget(deviceId), targets);
+        state.removeTouchingPointerFromWindow(deviceId, pointerId, oldWallpaper);
     }
 
     if (newWallpaper != nullptr) {
@@ -6843,7 +6862,7 @@
                                 InputTarget::Flags::DISPATCH_AS_SLIPPERY_ENTER |
                                         InputTarget::Flags::WINDOW_IS_OBSCURED |
                                         InputTarget::Flags::WINDOW_IS_PARTIALLY_OBSCURED,
-                                pointerIds);
+                                deviceId, pointerIds);
     }
 }
 
@@ -6851,7 +6870,7 @@
                                              ftl::Flags<InputTarget::Flags> newTargetFlags,
                                              const sp<WindowInfoHandle> fromWindowHandle,
                                              const sp<WindowInfoHandle> toWindowHandle,
-                                             TouchState& state,
+                                             TouchState& state, int32_t deviceId,
                                              std::bitset<MAX_POINTER_ID + 1> pointerIds) {
     const bool oldHasWallpaper = oldTargetFlags.test(InputTarget::Flags::FOREGROUND) &&
             fromWindowHandle->getInfo()->inputConfig.test(
@@ -6881,7 +6900,8 @@
                 oldTargetFlags & (InputTarget::Flags::SPLIT | InputTarget::Flags::DISPATCH_AS_IS);
         wallpaperFlags |= InputTarget::Flags::WINDOW_IS_OBSCURED |
                 InputTarget::Flags::WINDOW_IS_PARTIALLY_OBSCURED;
-        state.addOrUpdateWindow(newWallpaper, wallpaperFlags, pointerIds, downTimeInTarget);
+        state.addOrUpdateWindow(newWallpaper, wallpaperFlags, deviceId, pointerIds,
+                                downTimeInTarget);
         std::shared_ptr<Connection> wallpaperConnection =
                 getConnectionLocked(newWallpaper->getToken());
         if (wallpaperConnection != nullptr) {
diff --git a/services/inputflinger/dispatcher/InputDispatcher.h b/services/inputflinger/dispatcher/InputDispatcher.h
index cdce492..37f569e 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.h
+++ b/services/inputflinger/dispatcher/InputDispatcher.h
@@ -711,14 +711,14 @@
     void slipWallpaperTouch(ftl::Flags<InputTarget::Flags> targetFlags,
                             const sp<android::gui::WindowInfoHandle>& oldWindowHandle,
                             const sp<android::gui::WindowInfoHandle>& newWindowHandle,
-                            TouchState& state, int32_t pointerId,
+                            TouchState& state, int32_t deviceId, int32_t pointerId,
                             std::vector<InputTarget>& targets) const REQUIRES(mLock);
     void transferWallpaperTouch(ftl::Flags<InputTarget::Flags> oldTargetFlags,
                                 ftl::Flags<InputTarget::Flags> newTargetFlags,
                                 const sp<android::gui::WindowInfoHandle> fromWindowHandle,
                                 const sp<android::gui::WindowInfoHandle> toWindowHandle,
-                                TouchState& state, std::bitset<MAX_POINTER_ID + 1> pointerIds)
-            REQUIRES(mLock);
+                                TouchState& state, int32_t deviceId,
+                                std::bitset<MAX_POINTER_ID + 1> pointerIds) REQUIRES(mLock);
 
     sp<android::gui::WindowInfoHandle> findWallpaperWindowBelow(
             const sp<android::gui::WindowInfoHandle>& windowHandle) const REQUIRES(mLock);
diff --git a/services/inputflinger/dispatcher/TouchState.cpp b/services/inputflinger/dispatcher/TouchState.cpp
index 0a61d48..ef188c7 100644
--- a/services/inputflinger/dispatcher/TouchState.cpp
+++ b/services/inputflinger/dispatcher/TouchState.cpp
@@ -31,18 +31,19 @@
     *this = TouchState();
 }
 
-void TouchState::removeTouchedPointer(int32_t pointerId) {
+void TouchState::removeTouchingPointer(int32_t removedDeviceId, int32_t pointerId) {
     for (TouchedWindow& touchedWindow : windows) {
-        touchedWindow.removeTouchingPointer(pointerId);
+        touchedWindow.removeTouchingPointer(removedDeviceId, pointerId);
     }
     clearWindowsWithoutPointers();
 }
 
-void TouchState::removeTouchedPointerFromWindow(
-        int32_t pointerId, const sp<android::gui::WindowInfoHandle>& windowHandle) {
+void TouchState::removeTouchingPointerFromWindow(
+        int32_t removedDeviceId, int32_t pointerId,
+        const sp<android::gui::WindowInfoHandle>& windowHandle) {
     for (TouchedWindow& touchedWindow : windows) {
         if (touchedWindow.windowHandle == windowHandle) {
-            touchedWindow.removeTouchingPointer(pointerId);
+            touchedWindow.removeTouchingPointer(removedDeviceId, pointerId);
             clearWindowsWithoutPointers();
             return;
         }
@@ -58,13 +59,14 @@
 
 void TouchState::clearWindowsWithoutPointers() {
     std::erase_if(windows, [](const TouchedWindow& w) {
-        return w.pointerIds.none() && !w.hasHoveringPointers();
+        return !w.hasTouchingPointers() && !w.hasHoveringPointers();
     });
 }
 
 void TouchState::addOrUpdateWindow(const sp<WindowInfoHandle>& windowHandle,
                                    ftl::Flags<InputTarget::Flags> targetFlags,
-                                   std::bitset<MAX_POINTER_ID + 1> pointerIds,
+                                   int32_t addedDeviceId,
+                                   std::bitset<MAX_POINTER_ID + 1> touchingPointerIds,
                                    std::optional<nsecs_t> firstDownTimeInTarget) {
     for (TouchedWindow& touchedWindow : windows) {
         // We do not compare windows by token here because two windows that share the same token
@@ -75,11 +77,11 @@
                 touchedWindow.targetFlags.clear(InputTarget::Flags::DISPATCH_AS_IS);
             }
             // For cases like hover enter/exit or DISPATCH_AS_OUTSIDE a touch window might not have
-            // downTime set initially. Need to update existing window when an pointer is down for
-            // the window.
-            touchedWindow.pointerIds |= pointerIds;
-            if (!touchedWindow.firstDownTimeInTarget.has_value()) {
-                touchedWindow.firstDownTimeInTarget = firstDownTimeInTarget;
+            // downTime set initially. Need to update existing window when a pointer is down for the
+            // window.
+            touchedWindow.addTouchingPointers(addedDeviceId, touchingPointerIds);
+            if (firstDownTimeInTarget) {
+                touchedWindow.trySetDownTimeInTarget(addedDeviceId, *firstDownTimeInTarget);
             }
             return;
         }
@@ -87,8 +89,10 @@
     TouchedWindow touchedWindow;
     touchedWindow.windowHandle = windowHandle;
     touchedWindow.targetFlags = targetFlags;
-    touchedWindow.pointerIds = pointerIds;
-    touchedWindow.firstDownTimeInTarget = firstDownTimeInTarget;
+    touchedWindow.addTouchingPointers(addedDeviceId, touchingPointerIds);
+    if (firstDownTimeInTarget) {
+        touchedWindow.trySetDownTimeInTarget(addedDeviceId, *firstDownTimeInTarget);
+    }
     windows.push_back(touchedWindow);
 }
 
@@ -130,12 +134,12 @@
     }
 }
 
-void TouchState::cancelPointersForWindowsExcept(std::bitset<MAX_POINTER_ID + 1> pointerIds,
+void TouchState::cancelPointersForWindowsExcept(int32_t touchedDeviceId,
+                                                std::bitset<MAX_POINTER_ID + 1> pointerIds,
                                                 const sp<IBinder>& token) {
-    if (pointerIds.none()) return;
-    std::for_each(windows.begin(), windows.end(), [&pointerIds, &token](TouchedWindow& w) {
+    std::for_each(windows.begin(), windows.end(), [&](TouchedWindow& w) {
         if (w.windowHandle->getToken() != token) {
-            w.pointerIds &= ~pointerIds;
+            w.removeTouchingPointers(touchedDeviceId, pointerIds);
         }
     });
     clearWindowsWithoutPointers();
@@ -149,24 +153,29 @@
  */
 void TouchState::cancelPointersForNonPilferingWindows() {
     // First, find all pointers that are being pilfered, across all windows
-    std::bitset<MAX_POINTER_ID + 1> allPilferedPointerIds;
-    std::for_each(windows.begin(), windows.end(), [&allPilferedPointerIds](const TouchedWindow& w) {
-        allPilferedPointerIds |= w.pilferedPointerIds;
-    });
+    std::map<int32_t /*deviceId*/, std::bitset<MAX_POINTER_ID + 1>> allPilferedPointerIdsByDevice;
+    for (const TouchedWindow& w : windows) {
+        for (const auto& [iterDeviceId, pilferedPointerIds] : w.getPilferingPointers()) {
+            allPilferedPointerIdsByDevice[iterDeviceId] |= pilferedPointerIds;
+        }
+    };
 
     // Optimization: most of the time, pilfering does not occur
-    if (allPilferedPointerIds.none()) return;
+    if (allPilferedPointerIdsByDevice.empty()) return;
 
     // Now, remove all pointers from every window that's being pilfered by other windows.
     // For example, if window A is pilfering pointer 1 (only), and window B is pilfering pointer 2
     // (only), the remove pointer 2 from window A and pointer 1 from window B. Usually, the set of
     // pilfered pointers will be disjoint across all windows, but there's no reason to cause that
     // limitation here.
-    std::for_each(windows.begin(), windows.end(), [&allPilferedPointerIds](TouchedWindow& w) {
-        std::bitset<MAX_POINTER_ID + 1> pilferedByOtherWindows =
-                w.pilferedPointerIds ^ allPilferedPointerIds;
-        w.pointerIds &= ~pilferedByOtherWindows;
-    });
+    for (const auto& [iterDeviceId, allPilferedPointerIds] : allPilferedPointerIdsByDevice) {
+        std::for_each(windows.begin(), windows.end(), [&](TouchedWindow& w) {
+            std::bitset<MAX_POINTER_ID + 1> pilferedByOtherWindows =
+                    w.getPilferingPointers(iterDeviceId) ^ allPilferedPointerIds;
+            // Remove all pointers pilfered by other windows
+            w.removeTouchingPointers(iterDeviceId, pilferedByOtherWindows);
+        });
+    }
     clearWindowsWithoutPointers();
 }
 
@@ -216,7 +225,7 @@
 
 bool TouchState::isDown() const {
     return std::any_of(windows.begin(), windows.end(),
-                       [](const TouchedWindow& window) { return window.pointerIds.any(); });
+                       [](const TouchedWindow& window) { return window.hasTouchingPointers(); });
 }
 
 bool TouchState::hasHoveringPointers() const {
@@ -245,12 +254,9 @@
 void TouchState::removeAllPointersForDevice(int32_t removedDeviceId) {
     for (TouchedWindow& window : windows) {
         window.removeAllHoveringPointersForDevice(removedDeviceId);
+        window.removeAllTouchingPointersForDevice(removedDeviceId);
     }
-    if (deviceId == removedDeviceId) {
-        for (TouchedWindow& window : windows) {
-            window.removeAllTouchingPointers();
-        }
-    }
+
     clearWindowsWithoutPointers();
 }
 
diff --git a/services/inputflinger/dispatcher/TouchState.h b/services/inputflinger/dispatcher/TouchState.h
index 15b840f..a2a9f75 100644
--- a/services/inputflinger/dispatcher/TouchState.h
+++ b/services/inputflinger/dispatcher/TouchState.h
@@ -43,24 +43,25 @@
     void reset();
     void clearWindowsWithoutPointers();
 
-    void removeTouchedPointer(int32_t pointerId);
-    void removeTouchedPointerFromWindow(int32_t pointerId,
-                                        const sp<android::gui::WindowInfoHandle>& windowHandle);
+    void removeTouchingPointer(int32_t deviceId, int32_t pointerId);
+    void removeTouchingPointerFromWindow(int32_t deviceId, int32_t pointerId,
+                                         const sp<android::gui::WindowInfoHandle>& windowHandle);
     void addOrUpdateWindow(const sp<android::gui::WindowInfoHandle>& windowHandle,
-                           ftl::Flags<InputTarget::Flags> targetFlags,
-                           std::bitset<MAX_POINTER_ID + 1> pointerIds,
+                           ftl::Flags<InputTarget::Flags> targetFlags, int32_t deviceId,
+                           std::bitset<MAX_POINTER_ID + 1> touchingPointerIds,
                            std::optional<nsecs_t> firstDownTimeInTarget = std::nullopt);
     void addHoveringPointerToWindow(const sp<android::gui::WindowInfoHandle>& windowHandle,
                                     int32_t deviceId, int32_t hoveringPointerId);
     void removeHoveringPointer(int32_t deviceId, int32_t hoveringPointerId);
     void clearHoveringPointers();
 
-    void removeAllPointersForDevice(int32_t removedDeviceId);
+    void removeAllPointersForDevice(int32_t deviceId);
     void removeWindowByToken(const sp<IBinder>& token);
     void filterNonAsIsTouchWindows();
 
     // Cancel pointers for current set of windows except the window with particular binder token.
-    void cancelPointersForWindowsExcept(std::bitset<MAX_POINTER_ID + 1> pointerIds,
+    void cancelPointersForWindowsExcept(int32_t deviceId,
+                                        std::bitset<MAX_POINTER_ID + 1> pointerIds,
                                         const sp<IBinder>& token);
     // Cancel pointers for current set of non-pilfering windows i.e. windows with isPilferingWindow
     // set to false.
diff --git a/services/inputflinger/dispatcher/TouchedWindow.cpp b/services/inputflinger/dispatcher/TouchedWindow.cpp
index d55d657..6ab97f8 100644
--- a/services/inputflinger/dispatcher/TouchedWindow.cpp
+++ b/services/inputflinger/dispatcher/TouchedWindow.cpp
@@ -16,6 +16,7 @@
 
 #include "TouchedWindow.h"
 
+#include <android-base/logging.h>
 #include <android-base/stringprintf.h>
 #include <input/PrintTools.h>
 
@@ -26,67 +27,228 @@
 namespace inputdispatcher {
 
 bool TouchedWindow::hasHoveringPointers() const {
-    return !mHoveringPointerIdsByDevice.empty();
+    for (const auto& [_, state] : mDeviceStates) {
+        if (state.hoveringPointerIds.any()) {
+            return true;
+        }
+    }
+    return false;
 }
 
 bool TouchedWindow::hasHoveringPointers(int32_t deviceId) const {
-    return mHoveringPointerIdsByDevice.find(deviceId) != mHoveringPointerIdsByDevice.end();
+    const auto stateIt = mDeviceStates.find(deviceId);
+    if (stateIt == mDeviceStates.end()) {
+        return false;
+    }
+    const DeviceState& state = stateIt->second;
+
+    return state.hoveringPointerIds.any();
 }
 
 void TouchedWindow::clearHoveringPointers() {
-    mHoveringPointerIdsByDevice.clear();
+    for (auto& [_, state] : mDeviceStates) {
+        state.hoveringPointerIds.reset();
+    }
+
+    std::erase_if(mDeviceStates, [](const auto& pair) { return !pair.second.hasPointers(); });
 }
 
 bool TouchedWindow::hasHoveringPointer(int32_t deviceId, int32_t pointerId) const {
-    auto it = mHoveringPointerIdsByDevice.find(deviceId);
-    if (it == mHoveringPointerIdsByDevice.end()) {
+    const auto stateIt = mDeviceStates.find(deviceId);
+    if (stateIt == mDeviceStates.end()) {
         return false;
     }
-    return it->second.test(pointerId);
+    const DeviceState& state = stateIt->second;
+
+    return state.hoveringPointerIds.test(pointerId);
 }
 
 void TouchedWindow::addHoveringPointer(int32_t deviceId, int32_t pointerId) {
-    const auto [it, _] = mHoveringPointerIdsByDevice.insert({deviceId, {}});
-    it->second.set(pointerId);
+    mDeviceStates[deviceId].hoveringPointerIds.set(pointerId);
 }
 
-void TouchedWindow::removeTouchingPointer(int32_t pointerId) {
-    pointerIds.reset(pointerId);
-    pilferedPointerIds.reset(pointerId);
-    if (pointerIds.none()) {
-        firstDownTimeInTarget.reset();
+void TouchedWindow::addTouchingPointer(int32_t deviceId, int32_t pointerId) {
+    mDeviceStates[deviceId].touchingPointerIds.set(pointerId);
+}
+
+void TouchedWindow::addTouchingPointers(int32_t deviceId,
+                                        std::bitset<MAX_POINTER_ID + 1> pointers) {
+    mDeviceStates[deviceId].touchingPointerIds |= pointers;
+}
+
+bool TouchedWindow::hasTouchingPointers() const {
+    for (const auto& [_, state] : mDeviceStates) {
+        if (state.touchingPointerIds.any()) {
+            return true;
+        }
+    }
+    return false;
+}
+
+bool TouchedWindow::hasTouchingPointers(int32_t deviceId) const {
+    return getTouchingPointers(deviceId).any();
+}
+
+bool TouchedWindow::hasTouchingPointer(int32_t deviceId, int32_t pointerId) const {
+    return getTouchingPointers(deviceId).test(pointerId);
+}
+
+std::bitset<MAX_POINTER_ID + 1> TouchedWindow::getTouchingPointers(int32_t deviceId) const {
+    const auto stateIt = mDeviceStates.find(deviceId);
+    if (stateIt == mDeviceStates.end()) {
+        return {};
+    }
+    const DeviceState& state = stateIt->second;
+
+    return state.touchingPointerIds;
+}
+
+void TouchedWindow::removeTouchingPointer(int32_t deviceId, int32_t pointerId) {
+    std::bitset<MAX_POINTER_ID + 1> pointerIds;
+    pointerIds.set(pointerId, true);
+
+    removeTouchingPointers(deviceId, pointerIds);
+}
+
+void TouchedWindow::removeTouchingPointers(int32_t deviceId,
+                                           std::bitset<MAX_POINTER_ID + 1> pointers) {
+    const auto stateIt = mDeviceStates.find(deviceId);
+    if (stateIt == mDeviceStates.end()) {
+        return;
+    }
+    DeviceState& state = stateIt->second;
+
+    state.touchingPointerIds &= ~pointers;
+    state.pilferingPointerIds &= ~pointers;
+
+    if (!state.hasPointers()) {
+        mDeviceStates.erase(stateIt);
     }
 }
 
-void TouchedWindow::removeAllTouchingPointers() {
-    pointerIds.reset();
+std::set<int32_t> TouchedWindow::getTouchingDeviceIds() const {
+    std::set<int32_t> deviceIds;
+    for (const auto& [deviceId, _] : mDeviceStates) {
+        deviceIds.insert(deviceId);
+    }
+    return deviceIds;
+}
+
+bool TouchedWindow::hasPilferingPointers(int32_t deviceId) const {
+    const auto stateIt = mDeviceStates.find(deviceId);
+    if (stateIt == mDeviceStates.end()) {
+        return false;
+    }
+    const DeviceState& state = stateIt->second;
+
+    return state.pilferingPointerIds.any();
+}
+
+void TouchedWindow::addPilferingPointers(int32_t deviceId,
+                                         std::bitset<MAX_POINTER_ID + 1> pointerIds) {
+    mDeviceStates[deviceId].pilferingPointerIds |= pointerIds;
+}
+
+void TouchedWindow::addPilferingPointer(int32_t deviceId, int32_t pointerId) {
+    mDeviceStates[deviceId].pilferingPointerIds.set(pointerId);
+}
+
+std::bitset<MAX_POINTER_ID + 1> TouchedWindow::getPilferingPointers(int32_t deviceId) const {
+    const auto stateIt = mDeviceStates.find(deviceId);
+    if (stateIt == mDeviceStates.end()) {
+        return {};
+    }
+    const DeviceState& state = stateIt->second;
+
+    return state.pilferingPointerIds;
+}
+
+std::map<int32_t, std::bitset<MAX_POINTER_ID + 1>> TouchedWindow::getPilferingPointers() const {
+    std::map<int32_t, std::bitset<MAX_POINTER_ID + 1>> out;
+    for (const auto& [deviceId, state] : mDeviceStates) {
+        out.emplace(deviceId, state.pilferingPointerIds);
+    }
+    return out;
+}
+
+std::optional<nsecs_t> TouchedWindow::getDownTimeInTarget(int32_t deviceId) const {
+    const auto stateIt = mDeviceStates.find(deviceId);
+    if (stateIt == mDeviceStates.end()) {
+        return {};
+    }
+    const DeviceState& state = stateIt->second;
+    return state.downTimeInTarget;
+}
+
+void TouchedWindow::trySetDownTimeInTarget(int32_t deviceId, nsecs_t downTime) {
+    auto [stateIt, _] = mDeviceStates.try_emplace(deviceId);
+    DeviceState& state = stateIt->second;
+
+    if (!state.downTimeInTarget) {
+        state.downTimeInTarget = downTime;
+    }
+}
+
+void TouchedWindow::removeAllTouchingPointersForDevice(int32_t deviceId) {
+    const auto stateIt = mDeviceStates.find(deviceId);
+    if (stateIt == mDeviceStates.end()) {
+        return;
+    }
+    DeviceState& state = stateIt->second;
+
+    state.touchingPointerIds.reset();
+    state.pilferingPointerIds.reset();
+    state.downTimeInTarget.reset();
+
+    if (!state.hasPointers()) {
+        mDeviceStates.erase(stateIt);
+    }
 }
 
 void TouchedWindow::removeHoveringPointer(int32_t deviceId, int32_t pointerId) {
-    const auto it = mHoveringPointerIdsByDevice.find(deviceId);
-    if (it == mHoveringPointerIdsByDevice.end()) {
+    const auto stateIt = mDeviceStates.find(deviceId);
+    if (stateIt == mDeviceStates.end()) {
         return;
     }
-    it->second.set(pointerId, false);
+    DeviceState& state = stateIt->second;
 
-    if (it->second.none()) {
-        mHoveringPointerIdsByDevice.erase(deviceId);
+    state.hoveringPointerIds.set(pointerId, false);
+
+    if (!state.hasPointers()) {
+        mDeviceStates.erase(stateIt);
     }
 }
 
 void TouchedWindow::removeAllHoveringPointersForDevice(int32_t deviceId) {
-    mHoveringPointerIdsByDevice.erase(deviceId);
+    const auto stateIt = mDeviceStates.find(deviceId);
+    if (stateIt == mDeviceStates.end()) {
+        return;
+    }
+    DeviceState& state = stateIt->second;
+
+    state.hoveringPointerIds.reset();
+
+    if (!state.hasPointers()) {
+        mDeviceStates.erase(stateIt);
+    }
+}
+
+std::string TouchedWindow::deviceStateToString(const TouchedWindow::DeviceState& state) {
+    return StringPrintf("[touchingPointerIds=%s, "
+                        "downTimeInTarget=%s, hoveringPointerIds=%s, pilferingPointerIds=%s]",
+                        bitsetToString(state.touchingPointerIds).c_str(),
+                        toString(state.downTimeInTarget).c_str(),
+                        bitsetToString(state.hoveringPointerIds).c_str(),
+                        bitsetToString(state.pilferingPointerIds).c_str());
 }
 
 std::string TouchedWindow::dump() const {
     std::string out;
-    std::string hoveringPointers =
-            dumpMap(mHoveringPointerIdsByDevice, constToString, bitsetToString);
-    out += StringPrintf("name='%s', pointerIds=%s, targetFlags=%s, firstDownTimeInTarget=%s, "
-                        "mHoveringPointerIdsByDevice=%s, pilferedPointerIds=%s\n",
-                        windowHandle->getName().c_str(), bitsetToString(pointerIds).c_str(),
-                        targetFlags.string().c_str(), toString(firstDownTimeInTarget).c_str(),
-                        hoveringPointers.c_str(), bitsetToString(pilferedPointerIds).c_str());
+    std::string deviceStates =
+            dumpMap(mDeviceStates, constToString, TouchedWindow::deviceStateToString);
+    out += StringPrintf("name='%s', targetFlags=%s, mDeviceStates=%s\n",
+                        windowHandle->getName().c_str(), targetFlags.string().c_str(),
+                        deviceStates.c_str());
     return out;
 }
 
diff --git a/services/inputflinger/dispatcher/TouchedWindow.h b/services/inputflinger/dispatcher/TouchedWindow.h
index 43e7169..e50ede5 100644
--- a/services/inputflinger/dispatcher/TouchedWindow.h
+++ b/services/inputflinger/dispatcher/TouchedWindow.h
@@ -20,6 +20,7 @@
 #include <input/Input.h>
 #include <utils/BitSet.h>
 #include <bitset>
+#include <set>
 #include "InputTarget.h"
 
 namespace android {
@@ -30,28 +31,62 @@
 struct TouchedWindow {
     sp<gui::WindowInfoHandle> windowHandle;
     ftl::Flags<InputTarget::Flags> targetFlags;
-    std::bitset<MAX_POINTER_ID + 1> pointerIds;
-    // The pointer ids of the pointers that this window is currently pilfering
-    std::bitset<MAX_POINTER_ID + 1> pilferedPointerIds;
-    // Time at which the first action down occurred on this window.
-    // NOTE: This is not initialized in case of HOVER entry/exit and DISPATCH_AS_OUTSIDE scenario.
-    std::optional<nsecs_t> firstDownTimeInTarget;
 
+    // Hovering
     bool hasHoveringPointers() const;
     bool hasHoveringPointers(int32_t deviceId) const;
-
     bool hasHoveringPointer(int32_t deviceId, int32_t pointerId) const;
     void addHoveringPointer(int32_t deviceId, int32_t pointerId);
     void removeHoveringPointer(int32_t deviceId, int32_t pointerId);
-    void removeTouchingPointer(int32_t pointerId);
 
-    void removeAllTouchingPointers();
+    // Touching
+    bool hasTouchingPointer(int32_t deviceId, int32_t pointerId) const;
+    bool hasTouchingPointers() const;
+    bool hasTouchingPointers(int32_t deviceId) const;
+    std::bitset<MAX_POINTER_ID + 1> getTouchingPointers(int32_t deviceId) const;
+    void addTouchingPointer(int32_t deviceId, int32_t pointerId);
+    void addTouchingPointers(int32_t deviceId, std::bitset<MAX_POINTER_ID + 1> pointers);
+    void removeTouchingPointer(int32_t deviceId, int32_t pointerId);
+    void removeTouchingPointers(int32_t deviceId, std::bitset<MAX_POINTER_ID + 1> pointers);
+    /**
+     * Get the currently active touching device id. If there isn't exactly 1 touching device, return
+     * nullopt.
+     */
+    std::set<int32_t> getTouchingDeviceIds() const;
+
+    // Pilfering pointers
+    bool hasPilferingPointers(int32_t deviceId) const;
+    void addPilferingPointers(int32_t deviceId, std::bitset<MAX_POINTER_ID + 1> pointerIds);
+    void addPilferingPointer(int32_t deviceId, int32_t pointerId);
+    std::bitset<MAX_POINTER_ID + 1> getPilferingPointers(int32_t deviceId) const;
+    std::map<int32_t, std::bitset<MAX_POINTER_ID + 1>> getPilferingPointers() const;
+
+    // Down time
+    std::optional<nsecs_t> getDownTimeInTarget(int32_t deviceId) const;
+    void trySetDownTimeInTarget(int32_t deviceId, nsecs_t downTime);
+
+    void removeAllTouchingPointersForDevice(int32_t deviceId);
     void removeAllHoveringPointersForDevice(int32_t deviceId);
     void clearHoveringPointers();
     std::string dump() const;
 
 private:
-    std::map<int32_t /*deviceId*/, std::bitset<MAX_POINTER_ID + 1>> mHoveringPointerIdsByDevice;
+    struct DeviceState {
+        std::bitset<MAX_POINTER_ID + 1> touchingPointerIds;
+        // The pointer ids of the pointers that this window is currently pilfering, by device
+        std::bitset<MAX_POINTER_ID + 1> pilferingPointerIds;
+        // Time at which the first action down occurred on this window, for each device
+        // NOTE: This is not initialized in case of HOVER entry/exit and DISPATCH_AS_OUTSIDE
+        // scenario.
+        std::optional<nsecs_t> downTimeInTarget;
+        std::bitset<MAX_POINTER_ID + 1> hoveringPointerIds;
+
+        bool hasPointers() const { return touchingPointerIds.any() || hoveringPointerIds.any(); };
+    };
+
+    std::map<int32_t /*deviceId*/, DeviceState> mDeviceStates;
+
+    static std::string deviceStateToString(const TouchedWindow::DeviceState& state);
 };
 
 } // namespace inputdispatcher