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Diffstat (limited to 'dom/cache/Context.cpp')
| -rw-r--r-- | dom/cache/Context.cpp | 1076 |
1 files changed, 1076 insertions, 0 deletions
diff --git a/dom/cache/Context.cpp b/dom/cache/Context.cpp new file mode 100644 index 0000000000..15fd9cb79a --- /dev/null +++ b/dom/cache/Context.cpp @@ -0,0 +1,1076 @@ +/* -*- 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/cache/Context.h" + +#include "CacheCommon.h" + +#include "mozilla/AutoRestore.h" +#include "mozilla/dom/SafeRefPtr.h" +#include "mozilla/dom/cache/Action.h" +#include "mozilla/dom/cache/FileUtils.h" +#include "mozilla/dom/cache/Manager.h" +#include "mozilla/dom/cache/ManagerId.h" +#include "mozilla/dom/quota/Assertions.h" +#include "mozilla/dom/quota/DirectoryLock.h" +#include "mozilla/dom/quota/QuotaManager.h" +#include "mozilla/dom/quota/ResultExtensions.h" +#include "mozilla/ipc/PBackgroundSharedTypes.h" +#include "mozIStorageConnection.h" +#include "nsIPrincipal.h" +#include "nsIRunnable.h" +#include "nsIThread.h" +#include "nsThreadUtils.h" + +namespace { + +using mozilla::dom::cache::Action; +using mozilla::dom::cache::CacheDirectoryMetadata; + +class NullAction final : public Action { + public: + NullAction() = default; + + virtual void RunOnTarget(mozilla::SafeRefPtr<Resolver> aResolver, + const mozilla::Maybe<CacheDirectoryMetadata>&, + Data*) override { + // Resolve success immediately. This Action does no actual work. + MOZ_DIAGNOSTIC_ASSERT(aResolver); + aResolver->Resolve(NS_OK); + } +}; + +} // namespace + +namespace mozilla::dom::cache { + +using mozilla::dom::quota::AssertIsOnIOThread; +using mozilla::dom::quota::DirectoryLock; +using mozilla::dom::quota::OpenDirectoryListener; +using mozilla::dom::quota::PERSISTENCE_TYPE_DEFAULT; +using mozilla::dom::quota::PersistenceType; +using mozilla::dom::quota::QuotaManager; + +class Context::Data final : public Action::Data { + public: + explicit Data(nsISerialEventTarget* aTarget) : mTarget(aTarget) { + MOZ_DIAGNOSTIC_ASSERT(mTarget); + } + + virtual mozIStorageConnection* GetConnection() const override { + MOZ_ASSERT(mTarget->IsOnCurrentThread()); + return mConnection; + } + + virtual void SetConnection(mozIStorageConnection* aConn) override { + MOZ_ASSERT(mTarget->IsOnCurrentThread()); + MOZ_DIAGNOSTIC_ASSERT(!mConnection); + mConnection = aConn; + MOZ_DIAGNOSTIC_ASSERT(mConnection); + } + + private: + ~Data() { + // We could proxy release our data here, but instead just assert. The + // Context code should guarantee that we are destroyed on the target + // thread once the connection is initialized. If we're not, then + // QuotaManager might race and try to clear the origin out from under us. + MOZ_ASSERT_IF(mConnection, mTarget->IsOnCurrentThread()); + } + + nsCOMPtr<nsISerialEventTarget> mTarget; + nsCOMPtr<mozIStorageConnection> mConnection; + + // Threadsafe counting because we're created on the PBackground thread + // and destroyed on the target IO thread. + NS_INLINE_DECL_THREADSAFE_REFCOUNTING(Context::Data) +}; + +// Executed to perform the complicated dance of steps necessary to initialize +// the QuotaManager. This must be performed for each origin before any disk +// IO occurrs. +class Context::QuotaInitRunnable final : public nsIRunnable, + public OpenDirectoryListener { + public: + QuotaInitRunnable(SafeRefPtr<Context> aContext, SafeRefPtr<Manager> aManager, + Data* aData, nsISerialEventTarget* aTarget, + SafeRefPtr<Action> aInitAction) + : mContext(std::move(aContext)), + mThreadsafeHandle(mContext->CreateThreadsafeHandle()), + mManager(std::move(aManager)), + mData(aData), + mTarget(aTarget), + mInitAction(std::move(aInitAction)), + mInitiatingEventTarget(GetCurrentSerialEventTarget()), + mResult(NS_OK), + mState(STATE_INIT), + mCanceled(false) { + MOZ_DIAGNOSTIC_ASSERT(mContext); + MOZ_DIAGNOSTIC_ASSERT(mManager); + MOZ_DIAGNOSTIC_ASSERT(mData); + MOZ_DIAGNOSTIC_ASSERT(mTarget); + MOZ_DIAGNOSTIC_ASSERT(mInitiatingEventTarget); + MOZ_DIAGNOSTIC_ASSERT(mInitAction); + } + + Maybe<DirectoryLock&> MaybeDirectoryLockRef() const { + NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable); + + return ToMaybeRef(mDirectoryLock.get()); + } + + nsresult Dispatch() { + NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable); + MOZ_DIAGNOSTIC_ASSERT(mState == STATE_INIT); + + mState = STATE_GET_INFO; + nsresult rv = NS_DispatchToMainThread(this, nsIThread::DISPATCH_NORMAL); + if (NS_WARN_IF(NS_FAILED(rv))) { + mState = STATE_COMPLETE; + Clear(); + } + return rv; + } + + void Cancel() { + NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable); + MOZ_DIAGNOSTIC_ASSERT(!mCanceled); + mCanceled = true; + mInitAction->CancelOnInitiatingThread(); + } + + // OpenDirectoryListener methods + virtual void DirectoryLockAcquired(DirectoryLock* aLock) override; + + virtual void DirectoryLockFailed() override; + + private: + class SyncResolver final : public Action::Resolver { + public: + SyncResolver() : mResolved(false), mResult(NS_OK) {} + + virtual void Resolve(nsresult aRv) override { + MOZ_DIAGNOSTIC_ASSERT(!mResolved); + mResolved = true; + mResult = aRv; + }; + + bool Resolved() const { return mResolved; } + nsresult Result() const { return mResult; } + + private: + ~SyncResolver() = default; + + bool mResolved; + nsresult mResult; + + NS_INLINE_DECL_REFCOUNTING(Context::QuotaInitRunnable::SyncResolver, + override) + }; + + ~QuotaInitRunnable() { + MOZ_DIAGNOSTIC_ASSERT(mState == STATE_COMPLETE); + MOZ_DIAGNOSTIC_ASSERT(!mContext); + MOZ_DIAGNOSTIC_ASSERT(!mInitAction); + } + + enum State { + STATE_INIT, + STATE_GET_INFO, + STATE_CREATE_QUOTA_MANAGER, + STATE_WAIT_FOR_DIRECTORY_LOCK, + STATE_ENSURE_ORIGIN_INITIALIZED, + STATE_RUN_ON_TARGET, + STATE_RUNNING, + STATE_COMPLETING, + STATE_COMPLETE + }; + + void Complete(nsresult aResult) { + MOZ_DIAGNOSTIC_ASSERT(mState == STATE_RUNNING || NS_FAILED(aResult)); + + MOZ_DIAGNOSTIC_ASSERT(NS_SUCCEEDED(mResult)); + mResult = aResult; + + mState = STATE_COMPLETING; + MOZ_ALWAYS_SUCCEEDS( + mInitiatingEventTarget->Dispatch(this, nsIThread::DISPATCH_NORMAL)); + } + + void Clear() { + NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable); + MOZ_DIAGNOSTIC_ASSERT(mContext); + mContext = nullptr; + mManager = nullptr; + mInitAction = nullptr; + } + + SafeRefPtr<Context> mContext; + SafeRefPtr<ThreadsafeHandle> mThreadsafeHandle; + SafeRefPtr<Manager> mManager; + RefPtr<Data> mData; + nsCOMPtr<nsISerialEventTarget> mTarget; + SafeRefPtr<Action> mInitAction; + nsCOMPtr<nsIEventTarget> mInitiatingEventTarget; + nsresult mResult; + Maybe<mozilla::ipc::PrincipalInfo> mPrincipalInfo; + Maybe<CacheDirectoryMetadata> mDirectoryMetadata; + RefPtr<DirectoryLock> mDirectoryLock; + State mState; + Atomic<bool> mCanceled; + + public: + NS_DECL_THREADSAFE_ISUPPORTS + NS_DECL_NSIRUNNABLE +}; + +void Context::QuotaInitRunnable::DirectoryLockAcquired(DirectoryLock* aLock) { + NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable); + MOZ_DIAGNOSTIC_ASSERT(aLock); + MOZ_DIAGNOSTIC_ASSERT(mState == STATE_WAIT_FOR_DIRECTORY_LOCK); + MOZ_DIAGNOSTIC_ASSERT(!mDirectoryLock); + + mDirectoryLock = aLock; + + MOZ_DIAGNOSTIC_ASSERT(mDirectoryLock->Id() >= 0); + mDirectoryMetadata->mDirectoryLockId = mDirectoryLock->Id(); + + if (mCanceled) { + Complete(NS_ERROR_ABORT); + return; + } + + QuotaManager* qm = QuotaManager::Get(); + MOZ_DIAGNOSTIC_ASSERT(qm); + + mState = STATE_ENSURE_ORIGIN_INITIALIZED; + nsresult rv = qm->IOThread()->Dispatch(this, nsIThread::DISPATCH_NORMAL); + if (NS_WARN_IF(NS_FAILED(rv))) { + Complete(rv); + return; + } +} + +void Context::QuotaInitRunnable::DirectoryLockFailed() { + NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable); + MOZ_DIAGNOSTIC_ASSERT(mState == STATE_WAIT_FOR_DIRECTORY_LOCK); + MOZ_DIAGNOSTIC_ASSERT(!mDirectoryLock); + + NS_WARNING("Failed to acquire a directory lock!"); + + Complete(NS_ERROR_FAILURE); +} + +NS_IMPL_ISUPPORTS(mozilla::dom::cache::Context::QuotaInitRunnable, nsIRunnable); + +// The QuotaManager init state machine is represented in the following diagram: +// +// +---------------+ +// | Start | Resolve(error) +// | (Orig Thread) +---------------------+ +// +-------+-------+ | +// | | +// +----------v-----------+ | +// | GetInfo | Resolve(error) | +// | (Main Thread) +-----------------+ +// +----------+-----------+ | +// | | +// +----------v-----------+ | +// | CreateQuotaManager | Resolve(error) | +// | (Orig Thread) +-----------------+ +// +----------+-----------+ | +// | | +// +----------v-----------+ | +// | WaitForDirectoryLock | Resolve(error) | +// | (Orig Thread) +-----------------+ +// +----------+-----------+ | +// | | +// +----------v------------+ | +// |EnsureOriginInitialized| Resolve(error) | +// | (Quota IO Thread) +----------------+ +// +----------+------------+ | +// | | +// +----------v------------+ | +// | RunOnTarget | Resolve(error) | +// | (Target Thread) +----------------+ +// +----------+------------+ | +// | | +// +---------v---------+ +------v------+ +// | Running | | Completing | +// | (Target Thread) +------------>(Orig Thread)| +// +-------------------+ +------+------+ +// | +// +-----v----+ +// | Complete | +// +----------+ +// +// The initialization process proceeds through the main states. If an error +// occurs, then we transition to Completing state back on the original thread. +NS_IMETHODIMP +Context::QuotaInitRunnable::Run() { + // May run on different threads depending on the state. See individual + // state cases for thread assertions. + + SafeRefPtr<SyncResolver> resolver = MakeSafeRefPtr<SyncResolver>(); + + switch (mState) { + // ----------------------------------- + case STATE_GET_INFO: { + MOZ_ASSERT(NS_IsMainThread()); + + auto res = [this]() -> Result<Ok, nsresult> { + if (mCanceled) { + return Err(NS_ERROR_ABORT); + } + + nsCOMPtr<nsIPrincipal> principal = mManager->GetManagerId().Principal(); + + mozilla::ipc::PrincipalInfo principalInfo; + QM_TRY( + MOZ_TO_RESULT(PrincipalToPrincipalInfo(principal, &principalInfo))); + + mPrincipalInfo.emplace(std::move(principalInfo)); + + mState = STATE_CREATE_QUOTA_MANAGER; + + MOZ_ALWAYS_SUCCEEDS( + mInitiatingEventTarget->Dispatch(this, nsIThread::DISPATCH_NORMAL)); + + return Ok{}; + }(); + + if (res.isErr()) { + resolver->Resolve(res.inspectErr()); + } + + break; + } + // ---------------------------------- + case STATE_CREATE_QUOTA_MANAGER: { + NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable); + + if (mCanceled || QuotaManager::IsShuttingDown()) { + resolver->Resolve(NS_ERROR_ABORT); + break; + } + + QM_TRY(QuotaManager::EnsureCreated(), QM_PROPAGATE, + [&resolver](const auto rv) { resolver->Resolve(rv); }); + + auto* const quotaManager = QuotaManager::Get(); + MOZ_DIAGNOSTIC_ASSERT(quotaManager); + + QM_TRY_UNWRAP( + auto principalMetadata, + quotaManager->GetInfoFromValidatedPrincipalInfo(*mPrincipalInfo)); + + mDirectoryMetadata.emplace(std::move(principalMetadata)); + + // Open directory + RefPtr<DirectoryLock> directoryLock = quotaManager->CreateDirectoryLock( + PERSISTENCE_TYPE_DEFAULT, *mDirectoryMetadata, + quota::Client::DOMCACHE, + /* aExclusive */ false); + + // DirectoryLock::Acquire() will hold a reference to us as a listener. We + // will then get DirectoryLockAcquired() on the owning thread when it is + // safe to access our storage directory. + mState = STATE_WAIT_FOR_DIRECTORY_LOCK; + directoryLock->Acquire(this); + + break; + } + // ---------------------------------- + case STATE_ENSURE_ORIGIN_INITIALIZED: { + AssertIsOnIOThread(); + + auto res = [this]() -> Result<Ok, nsresult> { + if (mCanceled) { + return Err(NS_ERROR_ABORT); + } + + QuotaManager* quotaManager = QuotaManager::Get(); + MOZ_DIAGNOSTIC_ASSERT(quotaManager); + + QM_TRY(MOZ_TO_RESULT(quotaManager->EnsureStorageIsInitialized())); + + QM_TRY( + MOZ_TO_RESULT(quotaManager->EnsureTemporaryStorageIsInitialized())); + + QM_TRY_UNWRAP(mDirectoryMetadata->mDir, + quotaManager + ->EnsureTemporaryOriginIsInitialized( + PERSISTENCE_TYPE_DEFAULT, *mDirectoryMetadata) + .map([](const auto& res) { return res.first; })); + + mState = STATE_RUN_ON_TARGET; + + MOZ_ALWAYS_SUCCEEDS( + mTarget->Dispatch(this, nsIThread::DISPATCH_NORMAL)); + + return Ok{}; + }(); + + if (res.isErr()) { + resolver->Resolve(res.inspectErr()); + } + + break; + } + // ------------------- + case STATE_RUN_ON_TARGET: { + MOZ_ASSERT(mTarget->IsOnCurrentThread()); + + mState = STATE_RUNNING; + + // Execute the provided initialization Action. The Action must Resolve() + // before returning. + mInitAction->RunOnTarget(resolver.clonePtr(), mDirectoryMetadata, mData); + MOZ_DIAGNOSTIC_ASSERT(resolver->Resolved()); + + mData = nullptr; + + // If the database was opened, then we should always succeed when creating + // the marker file. If it wasn't opened successfully, then no need to + // create a marker file anyway. + if (NS_SUCCEEDED(resolver->Result())) { + MOZ_ALWAYS_SUCCEEDS(CreateMarkerFile(*mDirectoryMetadata)); + } + + break; + } + // ------------------- + case STATE_COMPLETING: { + NS_ASSERT_OWNINGTHREAD(QuotaInitRunnable); + mInitAction->CompleteOnInitiatingThread(mResult); + mContext->OnQuotaInit(mResult, mDirectoryMetadata, + mDirectoryLock.forget()); + mState = STATE_COMPLETE; + + // Explicitly cleanup here as the destructor could fire on any of + // the threads we have bounced through. + Clear(); + break; + } + // ----- + case STATE_WAIT_FOR_DIRECTORY_LOCK: + default: { + MOZ_CRASH("unexpected state in QuotaInitRunnable"); + } + } + + if (resolver->Resolved()) { + Complete(resolver->Result()); + } + + return NS_OK; +} + +// Runnable wrapper around Action objects dispatched on the Context. This +// runnable executes the Action on the appropriate threads while the Context +// is initialized. +class Context::ActionRunnable final : public nsIRunnable, + public Action::Resolver, + public Context::Activity { + public: + ActionRunnable(SafeRefPtr<Context> aContext, Data* aData, + nsISerialEventTarget* aTarget, SafeRefPtr<Action> aAction, + const Maybe<CacheDirectoryMetadata>& aDirectoryMetadata) + : mContext(std::move(aContext)), + mData(aData), + mTarget(aTarget), + mAction(std::move(aAction)), + mDirectoryMetadata(aDirectoryMetadata), + mInitiatingThread(GetCurrentSerialEventTarget()), + mState(STATE_INIT), + mResult(NS_OK), + mExecutingRunOnTarget(false) { + MOZ_DIAGNOSTIC_ASSERT(mContext); + // mData may be nullptr + MOZ_DIAGNOSTIC_ASSERT(mTarget); + MOZ_DIAGNOSTIC_ASSERT(mAction); + // mDirectoryMetadata.mDir may be nullptr if QuotaInitRunnable failed + MOZ_DIAGNOSTIC_ASSERT(mInitiatingThread); + } + + nsresult Dispatch() { + NS_ASSERT_OWNINGTHREAD(ActionRunnable); + MOZ_DIAGNOSTIC_ASSERT(mState == STATE_INIT); + + mState = STATE_RUN_ON_TARGET; + nsresult rv = mTarget->Dispatch(this, nsIEventTarget::DISPATCH_NORMAL); + if (NS_WARN_IF(NS_FAILED(rv))) { + mState = STATE_COMPLETE; + Clear(); + } + return rv; + } + + virtual bool MatchesCacheId(CacheId aCacheId) const override { + NS_ASSERT_OWNINGTHREAD(ActionRunnable); + return mAction->MatchesCacheId(aCacheId); + } + + virtual void Cancel() override { + NS_ASSERT_OWNINGTHREAD(ActionRunnable); + mAction->CancelOnInitiatingThread(); + } + + virtual void Resolve(nsresult aRv) override { + MOZ_ASSERT(mTarget->IsOnCurrentThread()); + MOZ_DIAGNOSTIC_ASSERT(mState == STATE_RUNNING); + + mResult = aRv; + + // We ultimately must complete on the initiating thread, but bounce through + // the current thread again to ensure that we don't destroy objects and + // state out from under the currently running action's stack. + mState = STATE_RESOLVING; + + // If we were resolved synchronously within Action::RunOnTarget() then we + // can avoid a thread bounce and just resolve once RunOnTarget() returns. + // The Run() method will handle this by looking at mState after + // RunOnTarget() returns. + if (mExecutingRunOnTarget) { + return; + } + + // Otherwise we are in an asynchronous resolve. And must perform a thread + // bounce to run on the target thread again. + MOZ_ALWAYS_SUCCEEDS(mTarget->Dispatch(this, nsIThread::DISPATCH_NORMAL)); + } + + private: + ~ActionRunnable() { + MOZ_DIAGNOSTIC_ASSERT(mState == STATE_COMPLETE); + MOZ_DIAGNOSTIC_ASSERT(!mContext); + MOZ_DIAGNOSTIC_ASSERT(!mAction); + } + + void Clear() { + NS_ASSERT_OWNINGTHREAD(ActionRunnable); + MOZ_DIAGNOSTIC_ASSERT(mContext); + MOZ_DIAGNOSTIC_ASSERT(mAction); + mContext->RemoveActivity(*this); + mContext = nullptr; + mAction = nullptr; + } + + enum State { + STATE_INIT, + STATE_RUN_ON_TARGET, + STATE_RUNNING, + STATE_RESOLVING, + STATE_COMPLETING, + STATE_COMPLETE + }; + + SafeRefPtr<Context> mContext; + RefPtr<Data> mData; + nsCOMPtr<nsISerialEventTarget> mTarget; + SafeRefPtr<Action> mAction; + const Maybe<CacheDirectoryMetadata> mDirectoryMetadata; + nsCOMPtr<nsIEventTarget> mInitiatingThread; + State mState; + nsresult mResult; + + // Only accessible on target thread; + bool mExecutingRunOnTarget; + + public: + NS_DECL_THREADSAFE_ISUPPORTS + NS_DECL_NSIRUNNABLE +}; + +NS_IMPL_ISUPPORTS(mozilla::dom::cache::Context::ActionRunnable, nsIRunnable); + +// The ActionRunnable has a simpler state machine. It basically needs to run +// the action on the target thread and then complete on the original thread. +// +// +-------------+ +// | Start | +// |(Orig Thread)| +// +-----+-------+ +// | +// +-------v---------+ +// | RunOnTarget | +// |Target IO Thread)+---+ Resolve() +// +-------+---------+ | +// | | +// +-------v----------+ | +// | Running | | +// |(Target IO Thread)| | +// +------------------+ | +// | Resolve() | +// +-------v----------+ | +// | Resolving <--+ +-------------+ +// | | | Completing | +// |(Target IO Thread)+---------------------->(Orig Thread)| +// +------------------+ +-------+-----+ +// | +// | +// +----v---+ +// |Complete| +// +--------+ +// +// Its important to note that synchronous actions will effectively Resolve() +// out of the Running state immediately. Asynchronous Actions may remain +// in the Running state for some time, but normally the ActionRunnable itself +// does not see any execution there. Its all handled internal to the Action. +NS_IMETHODIMP +Context::ActionRunnable::Run() { + switch (mState) { + // ---------------------- + case STATE_RUN_ON_TARGET: { + MOZ_ASSERT(mTarget->IsOnCurrentThread()); + MOZ_DIAGNOSTIC_ASSERT(!mExecutingRunOnTarget); + + // Note that we are calling RunOnTarget(). This lets us detect + // if Resolve() is called synchronously. + AutoRestore<bool> executingRunOnTarget(mExecutingRunOnTarget); + mExecutingRunOnTarget = true; + + mState = STATE_RUNNING; + mAction->RunOnTarget(SafeRefPtrFromThis(), mDirectoryMetadata, mData); + + mData = nullptr; + + // Resolve was called synchronously from RunOnTarget(). We can + // immediately move to completing now since we are sure RunOnTarget() + // completed. + if (mState == STATE_RESOLVING) { + // Use recursion instead of switch case fall-through... Seems slightly + // easier to understand. + Run(); + } + + break; + } + // ----------------- + case STATE_RESOLVING: { + MOZ_ASSERT(mTarget->IsOnCurrentThread()); + // The call to Action::RunOnTarget() must have returned now if we + // are running on the target thread again. We may now proceed + // with completion. + mState = STATE_COMPLETING; + // Shutdown must be delayed until all Contexts are destroyed. Crash + // for this invariant violation. + MOZ_ALWAYS_SUCCEEDS( + mInitiatingThread->Dispatch(this, nsIThread::DISPATCH_NORMAL)); + break; + } + // ------------------- + case STATE_COMPLETING: { + NS_ASSERT_OWNINGTHREAD(ActionRunnable); + mAction->CompleteOnInitiatingThread(mResult); + mState = STATE_COMPLETE; + // Explicitly cleanup here as the destructor could fire on any of + // the threads we have bounced through. + Clear(); + break; + } + // ----------------- + default: { + MOZ_CRASH("unexpected state in ActionRunnable"); + break; + } + } + return NS_OK; +} + +void Context::ThreadsafeHandle::AllowToClose() { + if (mOwningEventTarget->IsOnCurrentThread()) { + AllowToCloseOnOwningThread(); + return; + } + + // Dispatch is guaranteed to succeed here because we block shutdown until + // all Contexts have been destroyed. + nsCOMPtr<nsIRunnable> runnable = NewRunnableMethod( + "dom::cache::Context::ThreadsafeHandle::AllowToCloseOnOwningThread", this, + &ThreadsafeHandle::AllowToCloseOnOwningThread); + MOZ_ALWAYS_SUCCEEDS(mOwningEventTarget->Dispatch(runnable.forget(), + nsIThread::DISPATCH_NORMAL)); +} + +void Context::ThreadsafeHandle::InvalidateAndAllowToClose() { + if (mOwningEventTarget->IsOnCurrentThread()) { + InvalidateAndAllowToCloseOnOwningThread(); + return; + } + + // Dispatch is guaranteed to succeed here because we block shutdown until + // all Contexts have been destroyed. + nsCOMPtr<nsIRunnable> runnable = NewRunnableMethod( + "dom::cache::Context::ThreadsafeHandle::" + "InvalidateAndAllowToCloseOnOwningThread", + this, &ThreadsafeHandle::InvalidateAndAllowToCloseOnOwningThread); + MOZ_ALWAYS_SUCCEEDS(mOwningEventTarget->Dispatch(runnable.forget(), + nsIThread::DISPATCH_NORMAL)); +} + +Context::ThreadsafeHandle::ThreadsafeHandle(SafeRefPtr<Context> aContext) + : mStrongRef(std::move(aContext)), + mWeakRef(mStrongRef.unsafeGetRawPtr()), + mOwningEventTarget(GetCurrentSerialEventTarget()) {} + +Context::ThreadsafeHandle::~ThreadsafeHandle() { + // Normally we only touch mStrongRef on the owning thread. This is safe, + // however, because when we do use mStrongRef on the owning thread we are + // always holding a strong ref to the ThreadsafeHandle via the owning + // runnable. So we cannot run the ThreadsafeHandle destructor simultaneously. + if (!mStrongRef || mOwningEventTarget->IsOnCurrentThread()) { + return; + } + + // Dispatch in NS_ProxyRelease is guaranteed to succeed here because we block + // shutdown until all Contexts have been destroyed. Therefore it is ok to have + // MOZ_ALWAYS_SUCCEED here. + MOZ_ALWAYS_SUCCEEDS(NS_ProxyRelease("Context::ThreadsafeHandle::mStrongRef", + mOwningEventTarget, mStrongRef.forget())); +} + +void Context::ThreadsafeHandle::AllowToCloseOnOwningThread() { + MOZ_ASSERT(mOwningEventTarget->IsOnCurrentThread()); + + // A Context "closes" when its ref count drops to zero. Dropping this + // strong ref is necessary, but not sufficient for the close to occur. + // Any outstanding IO will continue and keep the Context alive. Once + // the Context is idle, it will be destroyed. + + // First, tell the context to flush any target thread shared data. This + // data must be released on the target thread prior to running the Context + // destructor. This will schedule an Action which ensures that the + // ~Context() is not immediately executed when we drop the strong ref. + if (mStrongRef) { + mStrongRef->DoomTargetData(); + } + + // Now drop our strong ref and let Context finish running any outstanding + // Actions. + mStrongRef = nullptr; +} + +void Context::ThreadsafeHandle::InvalidateAndAllowToCloseOnOwningThread() { + MOZ_ASSERT(mOwningEventTarget->IsOnCurrentThread()); + // Cancel the Context through the weak reference. This means we can + // allow the Context to close by dropping the strong ref, but then + // still cancel ongoing IO if necessary. + if (mWeakRef) { + mWeakRef->Invalidate(); + } + // We should synchronously have AllowToCloseOnOwningThread called when + // the Context is canceled. + MOZ_DIAGNOSTIC_ASSERT(!mStrongRef); +} + +void Context::ThreadsafeHandle::ContextDestroyed(Context& aContext) { + MOZ_ASSERT(mOwningEventTarget->IsOnCurrentThread()); + MOZ_DIAGNOSTIC_ASSERT(!mStrongRef); + MOZ_DIAGNOSTIC_ASSERT(mWeakRef); + MOZ_DIAGNOSTIC_ASSERT(mWeakRef == &aContext); + mWeakRef = nullptr; +} + +// static +SafeRefPtr<Context> Context::Create(SafeRefPtr<Manager> aManager, + nsISerialEventTarget* aTarget, + SafeRefPtr<Action> aInitAction, + Maybe<Context&> aOldContext) { + auto context = MakeSafeRefPtr<Context>(std::move(aManager), aTarget, + std::move(aInitAction)); + context->Init(aOldContext); + return context; +} + +Context::Context(SafeRefPtr<Manager> aManager, nsISerialEventTarget* aTarget, + SafeRefPtr<Action> aInitAction) + : mManager(std::move(aManager)), + mTarget(aTarget), + mData(new Data(aTarget)), + mState(STATE_CONTEXT_PREINIT), + mOrphanedData(false), + mInitAction(std::move(aInitAction)) { + MOZ_DIAGNOSTIC_ASSERT(mManager); + MOZ_DIAGNOSTIC_ASSERT(mTarget); +} + +void Context::Dispatch(SafeRefPtr<Action> aAction) { + NS_ASSERT_OWNINGTHREAD(Context); + MOZ_DIAGNOSTIC_ASSERT(aAction); + MOZ_DIAGNOSTIC_ASSERT(mState != STATE_CONTEXT_CANCELED); + + if (mState == STATE_CONTEXT_CANCELED) { + return; + } + + if (mState == STATE_CONTEXT_INIT || mState == STATE_CONTEXT_PREINIT) { + PendingAction* pending = mPendingActions.AppendElement(); + pending->mAction = std::move(aAction); + return; + } + + MOZ_DIAGNOSTIC_ASSERT(mState == STATE_CONTEXT_READY); + DispatchAction(std::move(aAction)); +} + +Maybe<DirectoryLock&> Context::MaybeDirectoryLockRef() const { + NS_ASSERT_OWNINGTHREAD(Context); + + if (mState == STATE_CONTEXT_PREINIT) { + MOZ_DIAGNOSTIC_ASSERT(!mInitRunnable); + MOZ_DIAGNOSTIC_ASSERT(!mDirectoryLock); + + return Nothing(); + } + + if (mState == STATE_CONTEXT_INIT) { + MOZ_DIAGNOSTIC_ASSERT(!mDirectoryLock); + + return mInitRunnable->MaybeDirectoryLockRef(); + } + + return ToMaybeRef(mDirectoryLock.get()); +} + +void Context::CancelAll() { + NS_ASSERT_OWNINGTHREAD(Context); + + // In PREINIT state we have not dispatch the init action yet. Just + // forget it. + if (mState == STATE_CONTEXT_PREINIT) { + MOZ_DIAGNOSTIC_ASSERT(!mInitRunnable); + mInitAction = nullptr; + + // In INIT state we have dispatched the runnable, but not received the + // async completion yet. Cancel the runnable, but don't forget about it + // until we get OnQuotaInit() callback. + } else if (mState == STATE_CONTEXT_INIT) { + mInitRunnable->Cancel(); + } + + mState = STATE_CONTEXT_CANCELED; + mPendingActions.Clear(); + for (const auto& activity : mActivityList.ForwardRange()) { + activity->Cancel(); + } + AllowToClose(); +} + +bool Context::IsCanceled() const { + NS_ASSERT_OWNINGTHREAD(Context); + return mState == STATE_CONTEXT_CANCELED; +} + +void Context::Invalidate() { + NS_ASSERT_OWNINGTHREAD(Context); + mManager->NoteClosing(); + CancelAll(); +} + +void Context::AllowToClose() { + NS_ASSERT_OWNINGTHREAD(Context); + if (mThreadsafeHandle) { + mThreadsafeHandle->AllowToClose(); + } +} + +void Context::CancelForCacheId(CacheId aCacheId) { + NS_ASSERT_OWNINGTHREAD(Context); + + // Remove matching pending actions + mPendingActions.RemoveElementsBy([aCacheId](const auto& pendingAction) { + return pendingAction.mAction->MatchesCacheId(aCacheId); + }); + + // Cancel activities and let them remove themselves + for (const auto& activity : mActivityList.ForwardRange()) { + if (activity->MatchesCacheId(aCacheId)) { + activity->Cancel(); + } + } +} + +Context::~Context() { + NS_ASSERT_OWNINGTHREAD(Context); + MOZ_DIAGNOSTIC_ASSERT(mManager); + MOZ_DIAGNOSTIC_ASSERT(!mData); + + if (mThreadsafeHandle) { + mThreadsafeHandle->ContextDestroyed(*this); + } + + // Note, this may set the mOrphanedData flag. + mManager->RemoveContext(*this); + + if (mDirectoryMetadata && mDirectoryMetadata->mDir && !mOrphanedData) { + MOZ_ALWAYS_SUCCEEDS(DeleteMarkerFile(*mDirectoryMetadata)); + } + + if (mNextContext) { + mNextContext->Start(); + } +} + +void Context::Init(Maybe<Context&> aOldContext) { + NS_ASSERT_OWNINGTHREAD(Context); + + if (aOldContext) { + aOldContext->SetNextContext(SafeRefPtrFromThis()); + return; + } + + Start(); +} + +void Context::Start() { + NS_ASSERT_OWNINGTHREAD(Context); + + // Previous context closing delayed our start, but then we were canceled. + // In this case, just do nothing here. + if (mState == STATE_CONTEXT_CANCELED) { + MOZ_DIAGNOSTIC_ASSERT(!mInitRunnable); + MOZ_DIAGNOSTIC_ASSERT(!mInitAction); + // If we can't initialize the quota subsystem we will never be able to + // clear our shared data object via the target IO thread. Instead just + // clear it here to maintain the invariant that the shared data is + // cleared before Context destruction. + mData = nullptr; + return; + } + + MOZ_DIAGNOSTIC_ASSERT(mState == STATE_CONTEXT_PREINIT); + MOZ_DIAGNOSTIC_ASSERT(!mInitRunnable); + + mInitRunnable = + new QuotaInitRunnable(SafeRefPtrFromThis(), mManager.clonePtr(), mData, + mTarget, std::move(mInitAction)); + mState = STATE_CONTEXT_INIT; + + nsresult rv = mInitRunnable->Dispatch(); + if (NS_FAILED(rv)) { + // Shutdown must be delayed until all Contexts are destroyed. Shutdown + // must also prevent any new Contexts from being constructed. Crash + // for this invariant violation. + MOZ_CRASH("Failed to dispatch QuotaInitRunnable."); + } +} + +void Context::DispatchAction(SafeRefPtr<Action> aAction, bool aDoomData) { + NS_ASSERT_OWNINGTHREAD(Context); + + auto runnable = + MakeSafeRefPtr<ActionRunnable>(SafeRefPtrFromThis(), mData, mTarget, + std::move(aAction), mDirectoryMetadata); + + if (aDoomData) { + mData = nullptr; + } + + nsresult rv = runnable->Dispatch(); + if (NS_FAILED(rv)) { + // Shutdown must be delayed until all Contexts are destroyed. Crash + // for this invariant violation. + MOZ_CRASH("Failed to dispatch ActionRunnable to target thread."); + } + AddActivity(*runnable); +} + +void Context::OnQuotaInit( + nsresult aRv, const Maybe<CacheDirectoryMetadata>& aDirectoryMetadata, + already_AddRefed<DirectoryLock> aDirectoryLock) { + NS_ASSERT_OWNINGTHREAD(Context); + + MOZ_DIAGNOSTIC_ASSERT(mInitRunnable); + mInitRunnable = nullptr; + + if (aDirectoryMetadata) { + mDirectoryMetadata.emplace(*aDirectoryMetadata); + } + + // Always save the directory lock to ensure QuotaManager does not shutdown + // before the Context has gone away. + MOZ_DIAGNOSTIC_ASSERT(!mDirectoryLock); + mDirectoryLock = aDirectoryLock; + + // If we opening the context failed, but we were not explicitly canceled, + // still treat the entire context as canceled. We don't want to allow + // new actions to be dispatched. We also cannot leave the context in + // the INIT state after failing to open. + if (NS_FAILED(aRv)) { + mState = STATE_CONTEXT_CANCELED; + } + + if (mState == STATE_CONTEXT_CANCELED) { + for (uint32_t i = 0; i < mPendingActions.Length(); ++i) { + mPendingActions[i].mAction->CompleteOnInitiatingThread(aRv); + } + mPendingActions.Clear(); + mThreadsafeHandle->AllowToClose(); + // Context will destruct after return here and last ref is released. + return; + } + + MOZ_DIAGNOSTIC_ASSERT(mState == STATE_CONTEXT_INIT); + mState = STATE_CONTEXT_READY; + + for (uint32_t i = 0; i < mPendingActions.Length(); ++i) { + DispatchAction(std::move(mPendingActions[i].mAction)); + } + mPendingActions.Clear(); +} + +void Context::AddActivity(Activity& aActivity) { + NS_ASSERT_OWNINGTHREAD(Context); + MOZ_ASSERT(!mActivityList.Contains(&aActivity)); + mActivityList.AppendElement(WrapNotNullUnchecked(&aActivity)); +} + +void Context::RemoveActivity(Activity& aActivity) { + NS_ASSERT_OWNINGTHREAD(Context); + MOZ_ALWAYS_TRUE(mActivityList.RemoveElement(&aActivity)); + MOZ_ASSERT(!mActivityList.Contains(&aActivity)); +} + +void Context::NoteOrphanedData() { + NS_ASSERT_OWNINGTHREAD(Context); + // This may be called more than once + mOrphanedData = true; +} + +SafeRefPtr<Context::ThreadsafeHandle> Context::CreateThreadsafeHandle() { + NS_ASSERT_OWNINGTHREAD(Context); + if (!mThreadsafeHandle) { + mThreadsafeHandle = MakeSafeRefPtr<ThreadsafeHandle>(SafeRefPtrFromThis()); + } + return mThreadsafeHandle.clonePtr(); +} + +void Context::SetNextContext(SafeRefPtr<Context> aNextContext) { + NS_ASSERT_OWNINGTHREAD(Context); + MOZ_DIAGNOSTIC_ASSERT(aNextContext); + MOZ_DIAGNOSTIC_ASSERT(!mNextContext); + mNextContext = std::move(aNextContext); +} + +void Context::DoomTargetData() { + NS_ASSERT_OWNINGTHREAD(Context); + MOZ_DIAGNOSTIC_ASSERT(mData); + + // We are about to drop our reference to the Data. We need to ensure that + // the ~Context() destructor does not run until contents of Data have been + // released on the Target thread. + + // Dispatch a no-op Action. This will hold the Context alive through a + // roundtrip to the target thread and back to the owning thread. The + // ref to the Data object is cleared on the owning thread after creating + // the ActionRunnable, but before dispatching it. + DispatchAction(MakeSafeRefPtr<NullAction>(), true /* doomed data */); + + MOZ_DIAGNOSTIC_ASSERT(!mData); +} + +} // namespace mozilla::dom::cache |