tor-browser

LockManagerParent.cpp (5955B)

---

/* -*- 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 "LockManagerParent.h"

#include "LockRequestParent.h"
#include "mozilla/PrincipalHashKey.h"
#include "mozilla/RefPtr.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/dom/locks/PLockManager.h"
#include "mozilla/media/MediaUtils.h"
#include "nsIDUtils.h"
#include "nsTHashMap.h"

namespace mozilla::dom::locks {

static StaticAutoPtr<nsTHashMap<PrincipalHashKey, WeakPtr<ManagedLocks>>>
   sManagedLocksMap;

using IPCResult = mozilla::ipc::IPCResult;

LockManagerParent::LockManagerParent(NotNull<nsIPrincipal*> aPrincipal,
                                    const Maybe<nsID>& aClientId)
   : mPrincipal(aPrincipal) {
 if (aClientId.isSome()) {
   mClientId = NSID_TrimBracketsUTF16(aClientId.value());
 } else {
   mClientId = EmptyString();
 }

 if (!sManagedLocksMap) {
   sManagedLocksMap =
       new nsTHashMap<PrincipalHashKey, WeakPtr<ManagedLocks>>();
 } else {
   mManagedLocks = sManagedLocksMap->Get(aPrincipal);
 }

 if (!mManagedLocks) {
   mManagedLocks = new ManagedLocks();
   sManagedLocksMap->LookupOrInsert(aPrincipal, mManagedLocks);
 }
}

void LockManagerParent::ActorDestroy(ActorDestroyReason aWhy) {
 if (!mManagedLocks) {
   return;
 }

 nsTArray<nsString> affectedResourceNames;

 mManagedLocks->mHeldLocks.RemoveElementsBy(
     [this, &affectedResourceNames](const RefPtr<LockRequestParent>& request) {
       bool equals = request->Manager() == this;
       if (equals) {
         affectedResourceNames.AppendElement(request->Data().name());
       }
       return equals;
     });

 for (auto& queue : mManagedLocks->mQueueMap) {
   queue.GetModifiableData()->RemoveElementsBy(
       [this, &name = queue.GetKey(),
        &affectedResourceNames](const RefPtr<LockRequestParent>& request) {
         bool equals = request->Manager() == this;
         if (equals) {
           affectedResourceNames.AppendElement(name);
         }
         return equals;
       });
 }

 for (const nsString& name : affectedResourceNames) {
   if (auto queue = mManagedLocks->mQueueMap.Lookup(name)) {
     ProcessRequestQueue(queue.Data());
   }
 }

 mManagedLocks = nullptr;
 // We just decreased the refcount and potentially deleted it, so check whether
 // the weak pointer still points to anything and remove the entry if not.
 if (!sManagedLocksMap->Get(mPrincipal)) {
   sManagedLocksMap->Remove(mPrincipal);
 }
}

void LockManagerParent::ProcessRequestQueue(
   nsTArray<RefPtr<LockRequestParent>>& aQueue) {
 while (aQueue.Length()) {
   RefPtr<LockRequestParent> first = aQueue[0];
   if (!IsGrantableRequest(first->Data())) {
     break;
   }
   aQueue.RemoveElementAt(0);
   mManagedLocks->mHeldLocks.AppendElement(first);
   (void)NS_WARN_IF(!first->SendResolve(first->Data().lockMode(), true));
 }
}

bool LockManagerParent::IsGrantableRequest(const IPCLockRequest& aRequest) {
 for (const auto& held : mManagedLocks->mHeldLocks) {
   if (held->Data().name() == aRequest.name()) {
     if (aRequest.lockMode() == LockMode::Exclusive) {
       return false;
     }
     MOZ_ASSERT(aRequest.lockMode() == LockMode::Shared);
     if (held->Data().lockMode() == LockMode::Exclusive) {
       return false;
     }
   }
 }
 return true;
}

IPCResult LockManagerParent::RecvQuery(QueryResolver&& aResolver) {
 LockManagerSnapshot snapshot;
 snapshot.mHeld.Construct();
 snapshot.mPending.Construct();
 for (const auto& queueMapEntry : mManagedLocks->mQueueMap) {
   for (const RefPtr<LockRequestParent>& request : queueMapEntry.GetData()) {
     LockInfo info;
     info.mMode.Construct(request->Data().lockMode());
     info.mName.Construct(request->Data().name());
     info.mClientId.Construct(
         static_cast<LockManagerParent*>(request->Manager())->mClientId);
     if (!snapshot.mPending.Value().AppendElement(info, mozilla::fallible)) {
       return IPC_FAIL(this, "Out of memory");
     };
   }
 }
 for (const RefPtr<LockRequestParent>& request : mManagedLocks->mHeldLocks) {
   LockInfo info;
   info.mMode.Construct(request->Data().lockMode());
   info.mName.Construct(request->Data().name());
   info.mClientId.Construct(
       static_cast<LockManagerParent*>(request->Manager())->mClientId);
   if (!snapshot.mHeld.Value().AppendElement(info, mozilla::fallible)) {
     return IPC_FAIL(this, "Out of memory");
   };
 }
 aResolver(snapshot);
 return IPC_OK();
};

already_AddRefed<PLockRequestParent> LockManagerParent::AllocPLockRequestParent(
   const IPCLockRequest& aRequest) {
 return MakeAndAddRef<LockRequestParent>(aRequest);
}

IPCResult LockManagerParent::RecvPLockRequestConstructor(
   PLockRequestParent* aActor, const IPCLockRequest& aRequest) {
 RefPtr<LockRequestParent> actor = static_cast<LockRequestParent*>(aActor);
 nsTArray<RefPtr<LockRequestParent>>& queue =
     mManagedLocks->mQueueMap.LookupOrInsert(aRequest.name());
 if (aRequest.steal()) {
   mManagedLocks->mHeldLocks.RemoveElementsBy(
       [&aRequest](const RefPtr<LockRequestParent>& aHeld) {
         if (aHeld->Data().name() == aRequest.name()) {
           (void)NS_WARN_IF(!PLockRequestParent::Send__delete__(aHeld, true));
           return true;
         }
         return false;
       });
   queue.InsertElementAt(0, actor);
 } else if (aRequest.ifAvailable() &&
            (!queue.IsEmpty() || !IsGrantableRequest(actor->Data()))) {
   (void)NS_WARN_IF(!aActor->SendResolve(aRequest.lockMode(), false));
   return IPC_OK();
 } else {
   queue.AppendElement(actor);
 }
 ProcessRequestQueue(queue);
 return IPC_OK();
}

}  // namespace mozilla::dom::locks