dom/locks/LockManagerParent.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "LockManagerParent.h"
   8 #include "LockRequestParent.h"
   9
  10 #include "mozilla/PrincipalHashKey.h"
  11 #include "mozilla/RefPtr.h"
  12 #include "mozilla/StaticPtr.h"
  13 #include "mozilla/dom/locks/PLockManager.h"
  14 #include "mozilla/media/MediaUtils.h"
  15 #include "nsIDUtils.h"
  16 #include "nsTHashMap.h"
  17
  18 namespace mozilla::dom::locks {
  19
  20 static StaticAutoPtr<nsTHashMap<PrincipalHashKey, WeakPtr<ManagedLocks>>>
  21     sManagedLocksMap;
  22
  23 using IPCResult = mozilla::ipc::IPCResult;
  24
  25 LockManagerParent::LockManagerParent(NotNull<nsIPrincipal*> aPrincipal,
  26                                      const nsID& aClientId)
  27     : mClientId(NSID_TrimBracketsUTF16(aClientId)), mPrincipal(aPrincipal) {
  28   if (!sManagedLocksMap) {
  29     sManagedLocksMap =
  30         new nsTHashMap<PrincipalHashKey, WeakPtr<ManagedLocks>>();
  31   } else {
  32     mManagedLocks = sManagedLocksMap->Get(aPrincipal);
  33   }
  34
  35   if (!mManagedLocks) {
  36     mManagedLocks = new ManagedLocks();
  37     sManagedLocksMap->LookupOrInsert(aPrincipal, mManagedLocks);
  38   }
  39 }
  40
  41 void LockManagerParent::ActorDestroy(ActorDestroyReason aWhy) {
  42   if (!mManagedLocks) {
  43     return;
  44   }
  45
  46   nsTArray<nsString> affectedResourceNames;
  47
  48   mManagedLocks->mHeldLocks.RemoveElementsBy(
  49       [this, &affectedResourceNames](const RefPtr<LockRequestParent>& request) {
  50         bool equals = request->Manager() == this;
  51         if (equals) {
  52           affectedResourceNames.AppendElement(request->Data().name());
  53         }
  54         return equals;
  55       });
  56
  57   for (auto& queue : mManagedLocks->mQueueMap) {
  58     queue.GetModifiableData()->RemoveElementsBy(
  59         [this, &name = queue.GetKey(),
  60          &affectedResourceNames](const RefPtr<LockRequestParent>& request) {
  61           bool equals = request->Manager() == this;
  62           if (equals) {
  63             affectedResourceNames.AppendElement(name);
  64           }
  65           return equals;
  66         });
  67   }
  68
  69   for (const nsString& name : affectedResourceNames) {
  70     if (auto queue = mManagedLocks->mQueueMap.Lookup(name)) {
  71       ProcessRequestQueue(queue.Data());
  72     }
  73   }
  74
  75   mManagedLocks = nullptr;
  76   // We just decreased the refcount and potentially deleted it, so check whether
  77   // the weak pointer still points to anything and remove the entry if not.
  78   if (!sManagedLocksMap->Get(mPrincipal)) {
  79     sManagedLocksMap->Remove(mPrincipal);
  80   }
  81 }
  82
  83 void LockManagerParent::ProcessRequestQueue(
  84     nsTArray<RefPtr<LockRequestParent>>& aQueue) {
  85   while (aQueue.Length()) {
  86     RefPtr<LockRequestParent> first = aQueue[0];
  87     if (!IsGrantableRequest(first->Data())) {
  88       break;
  89     }
  90     aQueue.RemoveElementAt(0);
  91     mManagedLocks->mHeldLocks.AppendElement(first);
  92     Unused << NS_WARN_IF(!first->SendResolve(first->Data().lockMode(), true));
  93   }
  94 }
  95
  96 bool LockManagerParent::IsGrantableRequest(const IPCLockRequest& aRequest) {
  97   for (const auto& held : mManagedLocks->mHeldLocks) {
  98     if (held->Data().name() == aRequest.name()) {
  99       if (aRequest.lockMode() == LockMode::Exclusive) {
 100         return false;
 101       }
 102       MOZ_ASSERT(aRequest.lockMode() == LockMode::Shared);
 103       if (held->Data().lockMode() == LockMode::Exclusive) {
 104         return false;
 105       }
 106     }
 107   }
 108   return true;
 109 }
 110
 111 IPCResult LockManagerParent::RecvQuery(QueryResolver&& aResolver) {
 112   LockManagerSnapshot snapshot;
 113   snapshot.mHeld.Construct();
 114   snapshot.mPending.Construct();
 115   for (const auto& queueMapEntry : mManagedLocks->mQueueMap) {
 116     for (const RefPtr<LockRequestParent>& request : queueMapEntry.GetData()) {
 117       LockInfo info;
 118       info.mMode.Construct(request->Data().lockMode());
 119       info.mName.Construct(request->Data().name());
 120       info.mClientId.Construct(
 121           static_cast<LockManagerParent*>(request->Manager())->mClientId);
 122       if (!snapshot.mPending.Value().AppendElement(info, mozilla::fallible)) {
 123         return IPC_FAIL(this, "Out of memory");
 124       };
 125     }
 126   }
 127   for (const RefPtr<LockRequestParent>& request : mManagedLocks->mHeldLocks) {
 128     LockInfo info;
 129     info.mMode.Construct(request->Data().lockMode());
 130     info.mName.Construct(request->Data().name());
 131     info.mClientId.Construct(
 132         static_cast<LockManagerParent*>(request->Manager())->mClientId);
 133     if (!snapshot.mHeld.Value().AppendElement(info, mozilla::fallible)) {
 134       return IPC_FAIL(this, "Out of memory");
 135     };
 136   }
 137   aResolver(snapshot);
 138   return IPC_OK();
 139 };
 140
 141 already_AddRefed<PLockRequestParent> LockManagerParent::AllocPLockRequestParent(
 142     const IPCLockRequest& aRequest) {
 143   return MakeAndAddRef<LockRequestParent>(aRequest);
 144 }
 145
 146 IPCResult LockManagerParent::RecvPLockRequestConstructor(
 147     PLockRequestParent* aActor, const IPCLockRequest& aRequest) {
 148   RefPtr<LockRequestParent> actor = static_cast<LockRequestParent*>(aActor);
 149   nsTArray<RefPtr<LockRequestParent>>& queue =
 150       mManagedLocks->mQueueMap.LookupOrInsert(aRequest.name());
 151   if (aRequest.steal()) {
 152     mManagedLocks->mHeldLocks.RemoveElementsBy(
 153         [&aRequest](const RefPtr<LockRequestParent>& aHeld) {
 154           if (aHeld->Data().name() == aRequest.name()) {
 155             Unused << NS_WARN_IF(
 156                 !PLockRequestParent::Send__delete__(aHeld, true));
 157             return true;
 158           }
 159           return false;
 160         });
 161     queue.InsertElementAt(0, actor);
 162   } else if (aRequest.ifAvailable() &&
 163              (!queue.IsEmpty() || !IsGrantableRequest(actor->Data()))) {
 164     Unused << NS_WARN_IF(!aActor->SendResolve(aRequest.lockMode(), false));
 165     return IPC_OK();
 166   } else {
 167     queue.AppendElement(actor);
 168   }
 169   ProcessRequestQueue(queue);
 170   return IPC_OK();
 171 }
 172
 173 }  // namespace mozilla::dom::locks