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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "mozilla/layers/APZUpdater.h"
#include "APZCTreeManager.h"
#include "AsyncPanZoomController.h"
#include "base/task.h"
#include "mozilla/ClearOnShutdown.h"
#include "mozilla/layers/APZThreadUtils.h"
#include "mozilla/layers/CompositorThread.h"
#include "mozilla/layers/SynchronousTask.h"
#include "mozilla/layers/WebRenderScrollDataWrapper.h"
#include "mozilla/webrender/WebRenderAPI.h"
namespace mozilla {
namespace layers {
StaticMutex APZUpdater::sWindowIdLock;
StaticAutoPtr<std::unordered_map<uint64_t, APZUpdater*>>
APZUpdater::sWindowIdMap;
APZUpdater::APZUpdater(const RefPtr<APZCTreeManager>& aApz,
bool aConnectedToWebRender)
: mApz(aApz),
mDestroyed(false),
mConnectedToWebRender(aConnectedToWebRender),
mThreadIdLock("APZUpdater::ThreadIdLock"),
mQueueLock("APZUpdater::QueueLock") {
MOZ_ASSERT(aApz);
mApz->SetUpdater(this);
}
APZUpdater::~APZUpdater() {
mApz->SetUpdater(nullptr);
StaticMutexAutoLock lock(sWindowIdLock);
if (mWindowId) {
MOZ_ASSERT(sWindowIdMap);
// Ensure that ClearTree was called and the task got run
MOZ_ASSERT(sWindowIdMap->find(wr::AsUint64(*mWindowId)) ==
sWindowIdMap->end());
}
}
bool APZUpdater::HasTreeManager(const RefPtr<APZCTreeManager>& aApz) {
return aApz.get() == mApz.get();
}
void APZUpdater::SetWebRenderWindowId(const wr::WindowId& aWindowId) {
StaticMutexAutoLock lock(sWindowIdLock);
MOZ_ASSERT(!mWindowId);
mWindowId = Some(aWindowId);
if (!sWindowIdMap) {
sWindowIdMap = new std::unordered_map<uint64_t, APZUpdater*>();
NS_DispatchToMainThread(NS_NewRunnableFunction(
"APZUpdater::ClearOnShutdown", [] { ClearOnShutdown(&sWindowIdMap); }));
}
(*sWindowIdMap)[wr::AsUint64(aWindowId)] = this;
}
/*static*/
void APZUpdater::SetUpdaterThread(const wr::WrWindowId& aWindowId) {
if (RefPtr<APZUpdater> updater = GetUpdater(aWindowId)) {
MutexAutoLock lock(updater->mThreadIdLock);
updater->mUpdaterThreadId = Some(PlatformThread::CurrentId());
}
}
// Takes a conditional lock!
/*static*/
void APZUpdater::PrepareForSceneSwap(const wr::WrWindowId& aWindowId)
MOZ_NO_THREAD_SAFETY_ANALYSIS {
if (RefPtr<APZUpdater> updater = GetUpdater(aWindowId)) {
updater->mApz->LockTree();
}
}
// Assumes we took a conditional lock!
/*static*/
void APZUpdater::CompleteSceneSwap(const wr::WrWindowId& aWindowId,
const wr::WrPipelineInfo& aInfo) {
RefPtr<APZUpdater> updater = GetUpdater(aWindowId);
if (!updater) {
// This should only happen in cases where PrepareForSceneSwap also got a
// null updater. No updater-thread tasks get run between PrepareForSceneSwap
// and this function, so there is no opportunity for the updater mapping
// to have gotten removed from sWindowIdMap in between the two calls.
return;
}
updater->mApz->mTreeLock.AssertCurrentThreadIn();
for (const auto& removedPipeline : aInfo.removed_pipelines) {
LayersId layersId = wr::AsLayersId(removedPipeline.pipeline_id);
updater->mEpochData.erase(layersId);
}
// Reset the built info for all pipelines, then put it back for the ones
// that got built in this scene swap.
for (auto& i : updater->mEpochData) {
i.second.mBuilt = Nothing();
}
for (const auto& epoch : aInfo.epochs) {
LayersId layersId = wr::AsLayersId(epoch.pipeline_id);
updater->mEpochData[layersId].mBuilt = Some(epoch.epoch);
}
// Run any tasks that got unblocked, then unlock the tree. The order is
// important because we want to run all the tasks up to and including the
// UpdateHitTestingTree calls corresponding to the built epochs, and we
// want to run those before we release the lock (i.e. atomically with the
// scene swap). This ensures that any hit-tests always encounter a consistent
// state between the APZ tree and the built scene in WR.
//
// While we could add additional information to the queued tasks to figure
// out the minimal set of tasks we want to run here, it's easier and harmless
// to just run all the queued and now-unblocked tasks inside the lock.
//
// Note that the ProcessQueue here might remove the window id -> APZUpdater
// mapping from sWindowIdMap, but we still unlock the tree successfully to
// leave things in a good state.
updater->ProcessQueue();
updater->mApz->UnlockTree();
}
/*static*/
void APZUpdater::ProcessPendingTasks(const wr::WrWindowId& aWindowId) {
if (RefPtr<APZUpdater> updater = GetUpdater(aWindowId)) {
updater->ProcessQueue();
}
}
void APZUpdater::ClearTree(LayersId aRootLayersId) {
MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
RefPtr<APZUpdater> self = this;
RunOnUpdaterThread(aRootLayersId,
NS_NewRunnableFunction("APZUpdater::ClearTree", [=]() {
self->mApz->ClearTree();
self->mDestroyed = true;
// Once ClearTree is called on the APZCTreeManager, we
// are in a shutdown phase. After this point it's ok if
// WebRender cannot get a hold of the updater via the
// window id, and it's a good point to remove the mapping
// and avoid leaving a dangling pointer to this object.
StaticMutexAutoLock lock(sWindowIdLock);
if (self->mWindowId) {
MOZ_ASSERT(sWindowIdMap);
sWindowIdMap->erase(wr::AsUint64(*(self->mWindowId)));
}
}));
}
void APZUpdater::UpdateFocusState(LayersId aRootLayerTreeId,
LayersId aOriginatingLayersId,
const FocusTarget& aFocusTarget) {
MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
RunOnUpdaterThread(aOriginatingLayersId,
NewRunnableMethod<LayersId, LayersId, FocusTarget>(
"APZUpdater::UpdateFocusState", mApz,
&APZCTreeManager::UpdateFocusState, aRootLayerTreeId,
aOriginatingLayersId, aFocusTarget));
}
void APZUpdater::UpdateScrollDataAndTreeState(
LayersId aRootLayerTreeId, LayersId aOriginatingLayersId,
const wr::Epoch& aEpoch, WebRenderScrollData&& aScrollData) {
MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
RefPtr<APZUpdater> self = this;
// Insert an epoch requirement update into the queue, so that
// tasks inserted into the queue after this point only get executed
// once the epoch requirement is satisfied. In particular, the
// UpdateHitTestingTree call below needs to wait until the epoch requirement
// is satisfied, which is why it is a separate task in the queue.
RunOnUpdaterThread(
aOriginatingLayersId,
NS_NewRunnableFunction("APZUpdater::UpdateEpochRequirement", [=]() {
if (aRootLayerTreeId == aOriginatingLayersId) {
self->mEpochData[aOriginatingLayersId].mIsRoot = true;
}
self->mEpochData[aOriginatingLayersId].mRequired = aEpoch;
}));
RunOnUpdaterThread(
aOriginatingLayersId,
NS_NewRunnableFunction(
"APZUpdater::UpdateHitTestingTree",
[=, aScrollData = std::move(aScrollData)]() mutable {
auto isFirstPaint = aScrollData.IsFirstPaint();
auto paintSequenceNumber = aScrollData.GetPaintSequenceNumber();
auto previous = self->mScrollData.find(aOriginatingLayersId);
// If there's the previous scroll data which hasn't yet been
// processed, we need to merge the previous scroll position updates
// into the latest one.
if (previous != self->mScrollData.end()) {
WebRenderScrollData& previousData = previous->second;
if (previousData.GetWasUpdateSkipped()) {
MOZ_ASSERT(previousData.IsFirstPaint());
aScrollData.PrependUpdates(previousData);
}
}
self->mScrollData[aOriginatingLayersId] = std::move(aScrollData);
auto root = self->mScrollData.find(aRootLayerTreeId);
if (root == self->mScrollData.end()) {
return;
}
if ((self->mApz->UpdateHitTestingTree(
WebRenderScrollDataWrapper(*self, &(root->second)),
isFirstPaint, aOriginatingLayersId, paintSequenceNumber) ==
APZCTreeManager::OriginatingLayersIdUpdated::No) &&
isFirstPaint) {
// If the given |aOriginatingLayersId| data wasn't used for
// updating, it's likly that the parent process hasn't yet
// received the LayersId as "ReferentId", thus we need to process
// it in a subsequent update where we got the "ReferentId".
//
// NOTE: We restrict the above previous scroll data prepending to
// the first paint case, otherwise the cumulative scroll data may
// be exploded if we have never received the "ReferenceId".
self->mScrollData[aOriginatingLayersId].SetWasUpdateSkipped();
}
}));
}
void APZUpdater::UpdateScrollOffsets(LayersId aRootLayerTreeId,
LayersId aOriginatingLayersId,
ScrollUpdatesMap&& aUpdates,
uint32_t aPaintSequenceNumber) {
MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
RefPtr<APZUpdater> self = this;
RunOnUpdaterThread(
aOriginatingLayersId,
NS_NewRunnableFunction(
"APZUpdater::UpdateScrollOffsets",
[=, updates = std::move(aUpdates)]() mutable {
self->mScrollData[aOriginatingLayersId].ApplyUpdates(
std::move(updates), aPaintSequenceNumber);
auto root = self->mScrollData.find(aRootLayerTreeId);
if (root == self->mScrollData.end()) {
return;
}
self->mApz->UpdateHitTestingTree(
WebRenderScrollDataWrapper(*self, &(root->second)),
/*isFirstPaint*/ false, aOriginatingLayersId,
aPaintSequenceNumber);
}));
}
void APZUpdater::NotifyLayerTreeAdopted(LayersId aLayersId,
const RefPtr<APZUpdater>& aOldUpdater) {
MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
RunOnUpdaterThread(aLayersId,
NewRunnableMethod<LayersId, RefPtr<APZCTreeManager>>(
"APZUpdater::NotifyLayerTreeAdopted", mApz,
&APZCTreeManager::NotifyLayerTreeAdopted, aLayersId,
aOldUpdater ? aOldUpdater->mApz : nullptr));
}
void APZUpdater::NotifyLayerTreeRemoved(LayersId aLayersId) {
MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
RefPtr<APZUpdater> self = this;
RunOnUpdaterThread(
aLayersId,
NS_NewRunnableFunction("APZUpdater::NotifyLayerTreeRemoved", [=]() {
self->mEpochData.erase(aLayersId);
self->mScrollData.erase(aLayersId);
self->mApz->NotifyLayerTreeRemoved(aLayersId);
}));
}
bool APZUpdater::GetAPZTestData(LayersId aLayersId, APZTestData* aOutData) {
MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
RefPtr<APZCTreeManager> apz = mApz;
bool ret = false;
SynchronousTask waiter("APZUpdater::GetAPZTestData");
RunOnUpdaterThread(
aLayersId, NS_NewRunnableFunction("APZUpdater::GetAPZTestData", [&]() {
AutoCompleteTask notifier(&waiter);
ret = apz->GetAPZTestData(aLayersId, aOutData);
}));
// Wait until the task posted above has run and populated aOutData and ret
waiter.Wait();
return ret;
}
void APZUpdater::SetTestAsyncScrollOffset(
LayersId aLayersId, const ScrollableLayerGuid::ViewID& aScrollId,
const CSSPoint& aOffset) {
MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
RefPtr<APZCTreeManager> apz = mApz;
RunOnUpdaterThread(
aLayersId,
NS_NewRunnableFunction("APZUpdater::SetTestAsyncScrollOffset", [=]() {
RefPtr<AsyncPanZoomController> apzc =
apz->GetTargetAPZC(aLayersId, aScrollId);
if (apzc) {
apzc->SetTestAsyncScrollOffset(aOffset);
} else {
NS_WARNING("Unable to find APZC in SetTestAsyncScrollOffset");
}
}));
}
void APZUpdater::SetTestAsyncZoom(LayersId aLayersId,
const ScrollableLayerGuid::ViewID& aScrollId,
const LayerToParentLayerScale& aZoom) {
MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
RefPtr<APZCTreeManager> apz = mApz;
RunOnUpdaterThread(
aLayersId, NS_NewRunnableFunction("APZUpdater::SetTestAsyncZoom", [=]() {
RefPtr<AsyncPanZoomController> apzc =
apz->GetTargetAPZC(aLayersId, aScrollId);
if (apzc) {
apzc->SetTestAsyncZoom(aZoom);
} else {
NS_WARNING("Unable to find APZC in SetTestAsyncZoom");
}
}));
}
const WebRenderScrollData* APZUpdater::GetScrollData(LayersId aLayersId) const {
AssertOnUpdaterThread();
auto it = mScrollData.find(aLayersId);
return (it == mScrollData.end() ? nullptr : &(it->second));
}
void APZUpdater::AssertOnUpdaterThread() const {
if (APZThreadUtils::GetThreadAssertionsEnabled()) {
MOZ_ASSERT(IsUpdaterThread());
}
}
void APZUpdater::RunOnUpdaterThread(LayersId aLayersId,
already_AddRefed<Runnable> aTask) {
RefPtr<Runnable> task = aTask;
// In the scenario where IsConnectedToWebRender() is true, this function
// might get called early (before mUpdaterThreadId is set). In that case
// IsUpdaterThread() will return false and we'll queue the task onto
// mUpdaterQueue. This is fine; the task is still guaranteed to run (barring
// catastrophic failure) because the WakeSceneBuilder call will still trigger
// the callback to run tasks.
if (IsUpdaterThread()) {
// This function should only be called from the updater thread in test
// scenarios where we are not connected to WebRender. If it were called from
// the updater thread when we are connected to WebRender, running the task
// right away would be incorrect (we'd need to check that |aLayersId|
// isn't blocked, and if it is then enqueue the task instead).
MOZ_ASSERT(!IsConnectedToWebRender());
task->Run();
return;
}
if (IsConnectedToWebRender()) {
// If the updater thread is a WebRender thread, and we're not on it
// right now, save the task in the queue. We will run tasks from the queue
// during the callback from the updater thread, which we trigger by the
// call to WakeSceneBuilder.
bool sendWakeMessage = true;
{ // scope lock
MutexAutoLock lock(mQueueLock);
for (const auto& queuedTask : mUpdaterQueue) {
if (queuedTask.mLayersId == aLayersId) {
// If there's already a task in the queue with this layers id, then
// we must have previously sent a WakeSceneBuilder message (when
// adding the first task with this layers id to the queue). Either
// that hasn't been fully processed yet, or the layers id is blocked
// waiting for an epoch - in either case there's no point in sending
// another WakeSceneBuilder message.
sendWakeMessage = false;
break;
}
}
mUpdaterQueue.push_back(QueuedTask{aLayersId, task});
}
if (sendWakeMessage) {
RefPtr<wr::WebRenderAPI> api = mApz->GetWebRenderAPI();
if (api) {
api->WakeSceneBuilder();
} else {
// Not sure if this can happen, but it might be possible. If it does,
// the task is in the queue, but if we didn't get a WebRenderAPI it
// might never run, or it might run later if we manage to get a
// WebRenderAPI later. For now let's just emit a warning, this can
// probably be upgraded to an assert later.
NS_WARNING("Possibly dropping task posted to updater thread");
}
}
return;
}
if (CompositorThread()) {
CompositorThread()->Dispatch(task.forget());
} else {
// Could happen during startup
NS_WARNING("Dropping task posted to updater thread");
}
}
bool APZUpdater::IsUpdaterThread() const {
if (IsConnectedToWebRender()) {
// If the updater thread id isn't set yet then we cannot be running on the
// updater thread (because we will have the thread id before we run any
// C++ code on it, and this function is only ever invoked from C++ code),
// so return false in that scenario.
MutexAutoLock lock(mThreadIdLock);
return mUpdaterThreadId && PlatformThread::CurrentId() == *mUpdaterThreadId;
}
return CompositorThreadHolder::IsInCompositorThread();
}
void APZUpdater::RunOnControllerThread(LayersId aLayersId,
already_AddRefed<Runnable> aTask) {
MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
RefPtr<Runnable> task = aTask;
RunOnUpdaterThread(
aLayersId,
NewRunnableFunction("APZUpdater::RunOnControllerThread",
&APZThreadUtils::RunOnControllerThread,
std::move(task), nsIThread::DISPATCH_NORMAL));
}
bool APZUpdater::IsConnectedToWebRender() const {
return mConnectedToWebRender;
}
/*static*/
already_AddRefed<APZUpdater> APZUpdater::GetUpdater(
const wr::WrWindowId& aWindowId) {
RefPtr<APZUpdater> updater;
StaticMutexAutoLock lock(sWindowIdLock);
if (sWindowIdMap) {
auto it = sWindowIdMap->find(wr::AsUint64(aWindowId));
if (it != sWindowIdMap->end()) {
updater = it->second;
}
}
return updater.forget();
}
void APZUpdater::ProcessQueue() {
MOZ_ASSERT(!mDestroyed);
{ // scope lock to check for emptiness
MutexAutoLock lock(mQueueLock);
if (mUpdaterQueue.empty()) {
return;
}
}
std::deque<QueuedTask> blockedTasks;
while (true) {
QueuedTask task;
{ // scope lock to extract a task
MutexAutoLock lock(mQueueLock);
if (mUpdaterQueue.empty()) {
// If we're done processing mUpdaterQueue, swap the tasks that are
// still blocked back in and finish
std::swap(mUpdaterQueue, blockedTasks);
break;
}
task = mUpdaterQueue.front();
mUpdaterQueue.pop_front();
}
// We check the task to see if it is blocked. Note that while this
// ProcessQueue function is executing, a particular layers id cannot go
// from blocked to unblocked, because only CompleteSceneSwap can unblock
// a layers id, and that also runs on the updater thread. If somehow
// a layers id gets unblocked while we're processing the queue, then it
// might result in tasks getting executed out of order.
auto it = mEpochData.find(task.mLayersId);
if (it != mEpochData.end() && it->second.IsBlocked()) {
// If this task is blocked, put it into the blockedTasks queue that
// we will replace mUpdaterQueue with
blockedTasks.push_back(task);
} else {
// Run and discard the task
task.mRunnable->Run();
}
}
if (mDestroyed) {
// If we get here, then we must have just run the ClearTree task for
// this updater. There might be tasks in the queue from content subtrees
// of this window that are blocked due to stale epochs. This can happen
// if the tasks were queued after the root pipeline was removed in
// WebRender, which prevents scene builds (and therefore prevents us
// comment 43 for some more context.
// To avoid leaking these tasks, we discard the contents of the queue.
// This happens during window shutdown so if we don't run the tasks it's
// not going to matter much.
MutexAutoLock lock(mQueueLock);
if (!mUpdaterQueue.empty()) {
mUpdaterQueue.clear();
}
}
}
void APZUpdater::MarkAsDetached(LayersId aLayersId) {
mApz->MarkAsDetached(aLayersId);
}
APZUpdater::EpochState::EpochState() : mRequired{0}, mIsRoot(false) {}
bool APZUpdater::EpochState::IsBlocked() const {
// The root is a special case because we basically assume it is "visible"
// even before it is built for the first time. This is because building the
// scene automatically makes it visible, and we need to make sure the APZ
// scroll data gets applied atomically with that happening.
//
// Layer subtrees on the other hand do not automatically become visible upon
// being built, because there must be a another layer tree update to change
// the visibility (i.e. an ancestor layer tree update that adds the necessary
// reflayer to complete the chain of reflayers).
//
// So in the case of non-visible subtrees, we know that no hit-test will
// actually end up hitting that subtree either before or after the scene swap,
// because the subtree will remain non-visible. That in turns means that we
// can apply the APZ scroll data for that subtree epoch before the scene is
// built, because it's not going to get used anyway. And that means we don't
// need to block the queue for non-visible subtrees. Which is a good thing,
// because in practice it seems like we often have non-visible subtrees sent
// to the compositor from content.
if (mIsRoot && !mBuilt) {
return true;
}
return mBuilt && (*mBuilt < mRequired);
}
} // namespace layers
} // namespace mozilla
// Rust callback implementations
void apz_register_updater(mozilla::wr::WrWindowId aWindowId) {
mozilla::layers::APZUpdater::SetUpdaterThread(aWindowId);
}
void apz_pre_scene_swap(mozilla::wr::WrWindowId aWindowId) {
mozilla::layers::APZUpdater::PrepareForSceneSwap(aWindowId);
}
void apz_post_scene_swap(mozilla::wr::WrWindowId aWindowId,
const mozilla::wr::WrPipelineInfo* aInfo) {
mozilla::layers::APZUpdater::CompleteSceneSwap(aWindowId, *aInfo);
}
void apz_run_updater(mozilla::wr::WrWindowId aWindowId) {
mozilla::layers::APZUpdater::ProcessPendingTasks(aWindowId);
}
void apz_deregister_updater(mozilla::wr::WrWindowId aWindowId) {
// Run anything that's still left.
mozilla::layers::APZUpdater::ProcessPendingTasks(aWindowId);
}