1 files changed, 460 insertions, 0 deletions
diff --git a/docshell/base/BrowsingContextGroup.cpp b/docshell/base/BrowsingContextGroup.cpp
new file mode 100644
index 0000000000..cf3bd9504d
--- /dev/null
+++ b/docshell/base/BrowsingContextGroup.cpp
@@ -0,0 +1,460 @@
+/* -*- 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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/BrowsingContextGroup.h"
+
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/InputTaskManager.h"
+#include "mozilla/dom/BrowsingContextBinding.h"
+#include "mozilla/dom/BindingUtils.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/dom/DocGroup.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/ThrottledEventQueue.h"
+#include "nsFocusManager.h"
+
+namespace mozilla {
+namespace dom {
+
+static StaticRefPtr<BrowsingContextGroup> sChromeGroup;
+
+static StaticAutoPtr<
+    nsDataHashtable<nsUint64HashKey, RefPtr<BrowsingContextGroup>>>
+    sBrowsingContextGroups;
+
+already_AddRefed<BrowsingContextGroup> BrowsingContextGroup::GetOrCreate(
+    uint64_t aId) {
+  if (!sBrowsingContextGroups) {
+    sBrowsingContextGroups =
+        new nsDataHashtable<nsUint64HashKey, RefPtr<BrowsingContextGroup>>();
+    ClearOnShutdown(&sBrowsingContextGroups);
+  }
+
+  auto entry = sBrowsingContextGroups->LookupForAdd(aId);
+  RefPtr<BrowsingContextGroup> group =
+      entry.OrInsert([&] { return do_AddRef(new BrowsingContextGroup(aId)); });
+  return group.forget();
+}
+
+already_AddRefed<BrowsingContextGroup> BrowsingContextGroup::Create() {
+  return GetOrCreate(nsContentUtils::GenerateBrowsingContextId());
+}
+
+BrowsingContextGroup::BrowsingContextGroup(uint64_t aId) : mId(aId) {
+  mTimerEventQueue = ThrottledEventQueue::Create(
+      GetMainThreadSerialEventTarget(), "BrowsingContextGroup timer queue");
+
+  mWorkerEventQueue = ThrottledEventQueue::Create(
+      GetMainThreadSerialEventTarget(), "BrowsingContextGroup worker queue");
+}
+
+void BrowsingContextGroup::Register(nsISupports* aContext) {
+  MOZ_ASSERT(!mDestroyed);
+  MOZ_DIAGNOSTIC_ASSERT(aContext);
+  mContexts.PutEntry(aContext);
+}
+
+void BrowsingContextGroup::Unregister(nsISupports* aContext) {
+  MOZ_ASSERT(!mDestroyed);
+  MOZ_DIAGNOSTIC_ASSERT(aContext);
+  mContexts.RemoveEntry(aContext);
+
+  MaybeDestroy();
+}
+
+void BrowsingContextGroup::EnsureHostProcess(ContentParent* aProcess) {
+  MOZ_ASSERT(!mDestroyed);
+  MOZ_DIAGNOSTIC_ASSERT(this != sChromeGroup,
+                        "cannot have content host for chrome group");
+  MOZ_DIAGNOSTIC_ASSERT(aProcess->GetRemoteType() != PREALLOC_REMOTE_TYPE,
+                        "cannot use preallocated process as host");
+  MOZ_DIAGNOSTIC_ASSERT(!aProcess->GetRemoteType().IsEmpty(),
+                        "host process must have remote type");
+
+  if (!aProcess->IsDead()) {
+    auto entry = mHosts.LookupForAdd(aProcess->GetRemoteType());
+    if (entry) {
+      MOZ_DIAGNOSTIC_ASSERT(
+          entry.Data() == aProcess,
+          "There's already another host process for this remote type");
+      return;
+    }
+
+    // This process wasn't already marked as our host, so insert it, and begin
+    // subscribing, unless the process is still launching.
+    entry.OrInsert([&] { return do_AddRef(aProcess); });
+  }
+
+  aProcess->AddBrowsingContextGroup(this);
+}
+
+void BrowsingContextGroup::RemoveHostProcess(ContentParent* aProcess) {
+  MOZ_DIAGNOSTIC_ASSERT(aProcess);
+  MOZ_DIAGNOSTIC_ASSERT(aProcess->GetRemoteType() != PREALLOC_REMOTE_TYPE);
+  auto entry = mHosts.Lookup(aProcess->GetRemoteType());
+  if (entry && entry.Data() == aProcess) {
+    entry.Remove();
+  }
+}
+
+static void CollectContextInitializers(
+    Span<RefPtr<BrowsingContext>> aContexts,
+    nsTArray<SyncedContextInitializer>& aInits) {
+  // The order that we record these initializers is important, as it will keep
+  // the order that children are attached to their parent in the newly connected
+  // content process consistent.
+  for (auto& context : aContexts) {
+    aInits.AppendElement(context->GetIPCInitializer());
+    for (auto& window : context->GetWindowContexts()) {
+      aInits.AppendElement(window->GetIPCInitializer());
+      CollectContextInitializers(window->Children(), aInits);
+    }
+  }
+}
+
+void BrowsingContextGroup::Subscribe(ContentParent* aProcess) {
+  MOZ_ASSERT(!mDestroyed);
+  MOZ_DIAGNOSTIC_ASSERT(aProcess && !aProcess->IsLaunching());
+  MOZ_DIAGNOSTIC_ASSERT(aProcess->GetRemoteType() != PREALLOC_REMOTE_TYPE);
+
+  // Check if we're already subscribed to this process.
+  if (!mSubscribers.EnsureInserted(aProcess)) {
+    return;
+  }
+
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  // If the process is already marked as dead, we won't be the host, but may
+  // still need to subscribe to the process due to creating a popup while
+  // shutting down.
+  if (!aProcess->IsDead()) {
+    auto hostEntry = mHosts.Lookup(aProcess->GetRemoteType());
+    MOZ_DIAGNOSTIC_ASSERT(hostEntry && hostEntry.Data() == aProcess,
+                          "Cannot subscribe a non-host process");
+  }
+#endif
+
+  // FIXME: This won't send non-discarded children of discarded BCs, but those
+  // BCs will be in the process of being destroyed anyway.
+  // FIXME: Prevent that situation from occuring.
+  nsTArray<SyncedContextInitializer> inits(mContexts.Count());
+  CollectContextInitializers(mToplevels, inits);
+
+  // Send all of our contexts to the target content process.
+  Unused << aProcess->SendRegisterBrowsingContextGroup(Id(), inits);
+
+  // If the focused or active BrowsingContexts belong in this group, tell the
+  // newly subscribed process.
+  if (nsFocusManager* fm = nsFocusManager::GetFocusManager()) {
+    BrowsingContext* focused = fm->GetFocusedBrowsingContextInChrome();
+    if (focused && focused->Group() != this) {
+      focused = nullptr;
+    }
+    BrowsingContext* active = fm->GetActiveBrowsingContextInChrome();
+    if (active && active->Group() != this) {
+      active = nullptr;
+    }
+
+    if (focused || active) {
+      Unused << aProcess->SendSetupFocusedAndActive(focused, active);
+    }
+  }
+}
+
+void BrowsingContextGroup::Unsubscribe(ContentParent* aProcess) {
+  MOZ_DIAGNOSTIC_ASSERT(aProcess);
+  MOZ_DIAGNOSTIC_ASSERT(aProcess->GetRemoteType() != PREALLOC_REMOTE_TYPE);
+  mSubscribers.RemoveEntry(aProcess);
+  aProcess->RemoveBrowsingContextGroup(this);
+
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  auto hostEntry = mHosts.Lookup(aProcess->GetRemoteType());
+  MOZ_DIAGNOSTIC_ASSERT(!hostEntry || hostEntry.Data() != aProcess,
+                        "Unsubscribing existing host entry");
+#endif
+}
+
+ContentParent* BrowsingContextGroup::GetHostProcess(
+    const nsACString& aRemoteType) {
+  return mHosts.GetWeak(aRemoteType);
+}
+
+void BrowsingContextGroup::UpdateToplevelsSuspendedIfNeeded() {
+  if (!StaticPrefs::dom_suspend_inactive_enabled()) {
+    return;
+  }
+
+  mToplevelsSuspended = ShouldSuspendAllTopLevelContexts();
+  for (const auto& context : mToplevels) {
+    nsPIDOMWindowOuter* outer = context->GetDOMWindow();
+    if (!outer) {
+      continue;
+    }
+    nsCOMPtr<nsPIDOMWindowInner> inner = outer->GetCurrentInnerWindow();
+    if (!inner) {
+      continue;
+    }
+    if (mToplevelsSuspended && !inner->GetWasSuspendedByGroup()) {
+      inner->Suspend();
+      inner->SetWasSuspendedByGroup(true);
+    } else if (!mToplevelsSuspended && inner->GetWasSuspendedByGroup()) {
+      inner->Resume();
+      inner->SetWasSuspendedByGroup(false);
+    }
+  }
+}
+
+bool BrowsingContextGroup::ShouldSuspendAllTopLevelContexts() const {
+  for (const auto& context : mToplevels) {
+    if (!context->InactiveForSuspend()) {
+      return false;
+    }
+  }
+  return true;
+}
+
+BrowsingContextGroup::~BrowsingContextGroup() { Destroy(); }
+
+void BrowsingContextGroup::Destroy() {
+#ifdef DEBUG
+  if (mDestroyed) {
+    MOZ_ASSERT(mHosts.Count() == 0);
+    MOZ_ASSERT(mSubscribers.Count() == 0);
+    MOZ_ASSERT_IF(sBrowsingContextGroups,
+                  sBrowsingContextGroups->Get(Id()) != this);
+  }
+  mDestroyed = true;
+#endif
+
+  // Make sure to call `RemoveBrowsingContextGroup` for every entry in both
+  // `mHosts` and `mSubscribers`. This will visit most entries twice, but
+  // `RemoveBrowsingContextGroup` is safe to call multiple times.
+  for (auto& entry : mHosts) {
+    entry.GetData()->RemoveBrowsingContextGroup(this);
+  }
+  for (auto& entry : mSubscribers) {
+    entry.GetKey()->RemoveBrowsingContextGroup(this);
+  }
+  mHosts.Clear();
+  mSubscribers.Clear();
+
+  if (sBrowsingContextGroups) {
+    sBrowsingContextGroups->Remove(Id());
+  }
+}
+
+void BrowsingContextGroup::AddKeepAlive() {
+  MOZ_ASSERT(!mDestroyed);
+  mKeepAliveCount++;
+}
+
+void BrowsingContextGroup::RemoveKeepAlive() {
+  MOZ_ASSERT(!mDestroyed);
+  MOZ_DIAGNOSTIC_ASSERT(mKeepAliveCount > 0);
+  mKeepAliveCount--;
+
+  MaybeDestroy();
+}
+
+void BrowsingContextGroup::MaybeDestroy() {
+  if (mContexts.IsEmpty() && mKeepAliveCount == 0 && this != sChromeGroup) {
+    // There are no synced contexts still referencing this group. We can clear
+    // all subscribers, and destroy ourselves.
+    Destroy();
+
+    // We may have been deleted here as the ContentChild/Parent may
+    // have held the last references to `this`.
+    // Do not access any members at this point.
+  }
+}
+
+nsISupports* BrowsingContextGroup::GetParentObject() const {
+  return xpc::NativeGlobal(xpc::PrivilegedJunkScope());
+}
+
+JSObject* BrowsingContextGroup::WrapObject(JSContext* aCx,
+                                           JS::Handle<JSObject*> aGivenProto) {
+  return BrowsingContextGroup_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+nsresult BrowsingContextGroup::QueuePostMessageEvent(
+    already_AddRefed<nsIRunnable>&& aRunnable) {
+  if (StaticPrefs::dom_separate_event_queue_for_post_message_enabled()) {
+    if (!mPostMessageEventQueue) {
+      nsCOMPtr<nsISerialEventTarget> target = GetMainThreadSerialEventTarget();
+      mPostMessageEventQueue = ThrottledEventQueue::Create(
+          target, "PostMessage Queue",
+          nsIRunnablePriority::PRIORITY_DEFERRED_TIMERS);
+      nsresult rv = mPostMessageEventQueue->SetIsPaused(false);
+      MOZ_ALWAYS_SUCCEEDS(rv);
+    }
+
+    // Ensure the queue is enabled
+    if (mPostMessageEventQueue->IsPaused()) {
+      nsresult rv = mPostMessageEventQueue->SetIsPaused(false);
+      MOZ_ALWAYS_SUCCEEDS(rv);
+    }
+
+    if (mPostMessageEventQueue) {
+      mPostMessageEventQueue->Dispatch(std::move(aRunnable),
+                                       NS_DISPATCH_NORMAL);
+      return NS_OK;
+    }
+  }
+  return NS_ERROR_FAILURE;
+}
+
+void BrowsingContextGroup::FlushPostMessageEvents() {
+  if (StaticPrefs::dom_separate_event_queue_for_post_message_enabled()) {
+    if (mPostMessageEventQueue) {
+      nsresult rv = mPostMessageEventQueue->SetIsPaused(true);
+      MOZ_ALWAYS_SUCCEEDS(rv);
+      nsCOMPtr<nsIRunnable> event;
+      while ((event = mPostMessageEventQueue->GetEvent())) {
+        NS_DispatchToMainThread(event.forget());
+      }
+    }
+  }
+}
+
+bool BrowsingContextGroup::HasActiveBC() {
+  for (auto& topLevelBC : Toplevels()) {
+    if (topLevelBC->IsActive()) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void BrowsingContextGroup::IncInputEventSuspensionLevel() {
+  MOZ_ASSERT(StaticPrefs::dom_input_events_canSuspendInBCG_enabled());
+  if (!mHasIncreasedInputTaskManagerSuspensionLevel && HasActiveBC()) {
+    IncInputTaskManagerSuspensionLevel();
+  }
+  ++mInputEventSuspensionLevel;
+}
+
+void BrowsingContextGroup::DecInputEventSuspensionLevel() {
+  MOZ_ASSERT(StaticPrefs::dom_input_events_canSuspendInBCG_enabled());
+  --mInputEventSuspensionLevel;
+  if (!mInputEventSuspensionLevel &&
+      mHasIncreasedInputTaskManagerSuspensionLevel) {
+    DecInputTaskManagerSuspensionLevel();
+  }
+}
+
+void BrowsingContextGroup::DecInputTaskManagerSuspensionLevel() {
+  MOZ_ASSERT(StaticPrefs::dom_input_events_canSuspendInBCG_enabled());
+  MOZ_ASSERT(mHasIncreasedInputTaskManagerSuspensionLevel);
+
+  InputTaskManager::Get()->DecSuspensionLevel();
+  mHasIncreasedInputTaskManagerSuspensionLevel = false;
+}
+
+void BrowsingContextGroup::IncInputTaskManagerSuspensionLevel() {
+  MOZ_ASSERT(StaticPrefs::dom_input_events_canSuspendInBCG_enabled());
+  MOZ_ASSERT(!mHasIncreasedInputTaskManagerSuspensionLevel);
+  MOZ_ASSERT(HasActiveBC());
+
+  InputTaskManager::Get()->IncSuspensionLevel();
+  mHasIncreasedInputTaskManagerSuspensionLevel = true;
+}
+
+void BrowsingContextGroup::UpdateInputTaskManagerIfNeeded(bool aIsActive) {
+  MOZ_ASSERT(StaticPrefs::dom_input_events_canSuspendInBCG_enabled());
+  if (!aIsActive) {
+    if (mHasIncreasedInputTaskManagerSuspensionLevel) {
+      MOZ_ASSERT(mInputEventSuspensionLevel > 0);
+      if (!HasActiveBC()) {
+        DecInputTaskManagerSuspensionLevel();
+      }
+    }
+  } else {
+    if (mInputEventSuspensionLevel &&
+        !mHasIncreasedInputTaskManagerSuspensionLevel) {
+      IncInputTaskManagerSuspensionLevel();
+    }
+  }
+}
+
+/* static */
+BrowsingContextGroup* BrowsingContextGroup::GetChromeGroup() {
+  MOZ_DIAGNOSTIC_ASSERT(XRE_IsParentProcess());
+  if (!sChromeGroup && XRE_IsParentProcess()) {
+    sChromeGroup = BrowsingContextGroup::Create();
+    ClearOnShutdown(&sChromeGroup);
+  }
+
+  return sChromeGroup;
+}
+
+void BrowsingContextGroup::GetDocGroups(nsTArray<DocGroup*>& aDocGroups) {
+  MOZ_ASSERT(NS_IsMainThread());
+  for (auto iter = mDocGroups.ConstIter(); !iter.Done(); iter.Next()) {
+    aDocGroups.AppendElement(iter.Data());
+  }
+}
+
+already_AddRefed<DocGroup> BrowsingContextGroup::AddDocument(
+    const nsACString& aKey, Document* aDocument) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  RefPtr<DocGroup>& docGroup = mDocGroups.GetOrInsert(aKey);
+  if (!docGroup) {
+    docGroup = DocGroup::Create(this, aKey);
+  }
+
+  docGroup->AddDocument(aDocument);
+  return do_AddRef(docGroup);
+}
+
+void BrowsingContextGroup::RemoveDocument(const nsACString& aKey,
+                                          Document* aDocument) {
+  MOZ_ASSERT(NS_IsMainThread());
+  RefPtr<DocGroup> docGroup = aDocument->GetDocGroup();
+  // Removing the last document in DocGroup might decrement the
+  // DocGroup BrowsingContextGroup's refcount to 0.
+  RefPtr<BrowsingContextGroup> kungFuDeathGrip(this);
+  docGroup->RemoveDocument(aDocument);
+
+  if (docGroup->IsEmpty()) {
+    mDocGroups.Remove(aKey);
+  }
+}
+
+already_AddRefed<BrowsingContextGroup> BrowsingContextGroup::Select(
+    WindowContext* aParent, BrowsingContext* aOpener) {
+  if (aParent) {
+    return do_AddRef(aParent->Group());
+  }
+  if (aOpener) {
+    return do_AddRef(aOpener->Group());
+  }
+  return Create();
+}
+
+void BrowsingContextGroup::GetAllGroups(
+    nsTArray<RefPtr<BrowsingContextGroup>>& aGroups) {
+  aGroups.Clear();
+  if (!sBrowsingContextGroups) {
+    return;
+  }
+
+  aGroups.SetCapacity(sBrowsingContextGroups->Count());
+  for (auto& group : *sBrowsingContextGroups) {
+    aGroups.AppendElement(group.GetData());
+  }
+}
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(BrowsingContextGroup, mContexts,
+                                      mToplevels, mHosts, mSubscribers,
+                                      mTimerEventQueue, mWorkerEventQueue)
+
+NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(BrowsingContextGroup, AddRef)
+NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(BrowsingContextGroup, Release)
+
+}  // namespace dom
+}  // namespace mozilla