Use sequence numbers to synchronize enabling Pointer Capture (1/2)
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.
Change-Id: I6ae9c5498dc2f783b4c7211fa3665d42e29d2919
diff --git a/services/inputflinger/dispatcher/InputDispatcher.cpp b/services/inputflinger/dispatcher/InputDispatcher.cpp
index 59cb419..e097773 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.cpp
+++ b/services/inputflinger/dispatcher/InputDispatcher.cpp
@@ -559,7 +559,6 @@
mInTouchMode(true),
mMaximumObscuringOpacityForTouch(1.0f),
mFocusedDisplayId(ADISPLAY_ID_DEFAULT),
- mFocusedWindowRequestedPointerCapture(false),
mWindowTokenWithPointerCapture(nullptr),
mLatencyAggregator(),
mLatencyTracker(&mLatencyAggregator),
@@ -1331,36 +1330,51 @@
void InputDispatcher::dispatchPointerCaptureChangedLocked(
nsecs_t currentTime, const std::shared_ptr<PointerCaptureChangedEntry>& entry,
DropReason& dropReason) {
+ dropReason = DropReason::NOT_DROPPED;
+
const bool haveWindowWithPointerCapture = mWindowTokenWithPointerCapture != nullptr;
- if (entry->pointerCaptureEnabled && haveWindowWithPointerCapture) {
- LOG_ALWAYS_FATAL("Pointer Capture has already been enabled for the window.");
- }
- if (!entry->pointerCaptureEnabled && !haveWindowWithPointerCapture) {
- // Pointer capture was already forcefully disabled because of focus change.
- dropReason = DropReason::NOT_DROPPED;
- return;
- }
-
- // Set drop reason for early returns
- dropReason = DropReason::NO_POINTER_CAPTURE;
-
sp<IBinder> token;
- if (entry->pointerCaptureEnabled) {
- // Enable Pointer Capture
- if (!mFocusedWindowRequestedPointerCapture) {
+
+ if (entry->pointerCaptureRequest.enable) {
+ // Enable Pointer Capture.
+ if (haveWindowWithPointerCapture &&
+ (entry->pointerCaptureRequest == mCurrentPointerCaptureRequest)) {
+ LOG_ALWAYS_FATAL("This request to enable Pointer Capture has already been dispatched "
+ "to the window.");
+ }
+ if (!mCurrentPointerCaptureRequest.enable) {
// This can happen if a window requests capture and immediately releases capture.
ALOGW("No window requested Pointer Capture.");
+ dropReason = DropReason::NO_POINTER_CAPTURE;
return;
}
+ if (entry->pointerCaptureRequest.seq != mCurrentPointerCaptureRequest.seq) {
+ ALOGI("Skipping dispatch of Pointer Capture being enabled: sequence number mismatch.");
+ return;
+ }
+
token = mFocusResolver.getFocusedWindowToken(mFocusedDisplayId);
LOG_ALWAYS_FATAL_IF(!token, "Cannot find focused window for Pointer Capture.");
mWindowTokenWithPointerCapture = token;
} else {
- // Disable Pointer Capture
+ // Disable Pointer Capture.
+ // We do not check if the sequence number matches for requests to disable Pointer Capture
+ // for two reasons:
+ // 1. Pointer Capture can be disabled by a focus change, which means we can get two entries
+ // to disable capture with the same sequence number: one generated by
+ // disablePointerCaptureForcedLocked() and another as an acknowledgement of Pointer
+ // Capture being disabled in InputReader.
+ // 2. We respect any request to disable Pointer Capture generated by InputReader, since the
+ // actual Pointer Capture state that affects events being generated by input devices is
+ // in InputReader.
+ if (!haveWindowWithPointerCapture) {
+ // Pointer capture was already forcefully disabled because of focus change.
+ dropReason = DropReason::NOT_DROPPED;
+ return;
+ }
token = mWindowTokenWithPointerCapture;
mWindowTokenWithPointerCapture = nullptr;
- if (mFocusedWindowRequestedPointerCapture) {
- mFocusedWindowRequestedPointerCapture = false;
+ if (mCurrentPointerCaptureRequest.enable) {
setPointerCaptureLocked(false);
}
}
@@ -1369,8 +1383,7 @@
if (channel == nullptr) {
// Window has gone away, clean up Pointer Capture state.
mWindowTokenWithPointerCapture = nullptr;
- if (mFocusedWindowRequestedPointerCapture) {
- mFocusedWindowRequestedPointerCapture = false;
+ if (mCurrentPointerCaptureRequest.enable) {
setPointerCaptureLocked(false);
}
return;
@@ -3183,7 +3196,7 @@
static_cast<const PointerCaptureChangedEntry&>(eventEntry);
status = connection->inputPublisher
.publishCaptureEvent(dispatchEntry->seq, captureEntry.id,
- captureEntry.pointerCaptureEnabled);
+ captureEntry.pointerCaptureRequest.enable);
break;
}
@@ -3999,14 +4012,14 @@
void InputDispatcher::notifyPointerCaptureChanged(const NotifyPointerCaptureChangedArgs* args) {
if (DEBUG_INBOUND_EVENT_DETAILS) {
ALOGD("notifyPointerCaptureChanged - eventTime=%" PRId64 ", enabled=%s", args->eventTime,
- args->enabled ? "true" : "false");
+ args->request.enable ? "true" : "false");
}
bool needWake;
{ // acquire lock
std::scoped_lock _l(mLock);
auto entry = std::make_unique<PointerCaptureChangedEntry>(args->id, args->eventTime,
- args->enabled);
+ args->request);
needWake = enqueueInboundEventLocked(std::move(entry));
} // release lock
@@ -4944,8 +4957,8 @@
std::string InputDispatcher::dumpPointerCaptureStateLocked() {
std::string dump;
- dump += StringPrintf(INDENT "FocusedWindowRequestedPointerCapture: %s\n",
- toString(mFocusedWindowRequestedPointerCapture));
+ dump += StringPrintf(INDENT "Pointer Capture Requested: %s\n",
+ toString(mCurrentPointerCaptureRequest.enable));
std::string windowName = "None";
if (mWindowTokenWithPointerCapture) {
@@ -4954,7 +4967,7 @@
windowName = captureWindowHandle ? captureWindowHandle->getName().c_str()
: "token has capture without window";
}
- dump += StringPrintf(INDENT "CurrentWindowWithPointerCapture: %s\n", windowName.c_str());
+ dump += StringPrintf(INDENT "Current Window with Pointer Capture: %s\n", windowName.c_str());
return dump;
}
@@ -5420,14 +5433,13 @@
return;
}
- if (enabled == mFocusedWindowRequestedPointerCapture) {
+ if (enabled == mCurrentPointerCaptureRequest.enable) {
ALOGW("Ignoring request to %s Pointer Capture: "
"window has %s requested pointer capture.",
enabled ? "enable" : "disable", enabled ? "already" : "not");
return;
}
- mFocusedWindowRequestedPointerCapture = enabled;
setPointerCaptureLocked(enabled);
} // release lock
@@ -6048,14 +6060,13 @@
}
void InputDispatcher::disablePointerCaptureForcedLocked() {
- if (!mFocusedWindowRequestedPointerCapture && !mWindowTokenWithPointerCapture) {
+ if (!mCurrentPointerCaptureRequest.enable && !mWindowTokenWithPointerCapture) {
return;
}
ALOGD_IF(DEBUG_FOCUS, "Disabling Pointer Capture because the window lost focus.");
- if (mFocusedWindowRequestedPointerCapture) {
- mFocusedWindowRequestedPointerCapture = false;
+ if (mCurrentPointerCaptureRequest.enable) {
setPointerCaptureLocked(false);
}
@@ -6072,14 +6083,16 @@
}
auto entry = std::make_unique<PointerCaptureChangedEntry>(mIdGenerator.nextId(), now(),
- false /* hasCapture */);
+ mCurrentPointerCaptureRequest);
mInboundQueue.push_front(std::move(entry));
}
-void InputDispatcher::setPointerCaptureLocked(bool enabled) {
- auto command = [this, enabled]() REQUIRES(mLock) {
+void InputDispatcher::setPointerCaptureLocked(bool enable) {
+ mCurrentPointerCaptureRequest.enable = enable;
+ mCurrentPointerCaptureRequest.seq++;
+ auto command = [this, request = mCurrentPointerCaptureRequest]() REQUIRES(mLock) {
scoped_unlock unlock(mLock);
- mPolicy->setPointerCapture(enabled);
+ mPolicy->setPointerCapture(request);
};
postCommandLocked(std::move(command));
}