Add m-esr52 at 52.6.0

1 files changed, 582 insertions, 0 deletions

diff --git a/xpcom/build/IOInterposer.cpp b/xpcom/build/IOInterposer.cpp
new file mode 100644
index 000000000..1c3ff54d5
--- /dev/null
+++ b/xpcom/build/IOInterposer.cpp
@@ -0,0 +1,582 @@
+/* -*- 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 <algorithm>
+#include <vector>
+
+#include "IOInterposer.h"
+
+#include "IOInterposerPrivate.h"
+#include "MainThreadIOLogger.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/ThreadLocal.h"
+#include "nscore.h" // for NS_FREE_PERMANENT_DATA
+#if !defined(XP_WIN)
+#include "NSPRInterposer.h"
+#endif // !defined(XP_WIN)
+#include "nsXULAppAPI.h"
+#include "PoisonIOInterposer.h"
+
+using namespace mozilla;
+
+namespace {
+
+/** Find if a vector contains a specific element */
+template<class T>
+bool
+VectorContains(const std::vector<T>& aVector, const T& aElement)
+{
+  return std::find(aVector.begin(), aVector.end(), aElement) != aVector.end();
+}
+
+/** Remove element from a vector */
+template<class T>
+void
+VectorRemove(std::vector<T>& aVector, const T& aElement)
+{
+  typename std::vector<T>::iterator newEnd =
+    std::remove(aVector.begin(), aVector.end(), aElement);
+  aVector.erase(newEnd, aVector.end());
+}
+
+/** Lists of Observers */
+struct ObserverLists
+{
+private:
+  ~ObserverLists() {}
+
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ObserverLists)
+
+  ObserverLists() {}
+
+  ObserverLists(ObserverLists const& aOther)
+    : mCreateObservers(aOther.mCreateObservers)
+    , mReadObservers(aOther.mReadObservers)
+    , mWriteObservers(aOther.mWriteObservers)
+    , mFSyncObservers(aOther.mFSyncObservers)
+    , mStatObservers(aOther.mStatObservers)
+    , mCloseObservers(aOther.mCloseObservers)
+    , mStageObservers(aOther.mStageObservers)
+  {
+  }
+  // Lists of observers for I/O events.
+  // These are implemented as vectors since they are allowed to survive gecko,
+  // without reporting leaks. This is necessary for the IOInterposer to be used
+  // for late-write checks.
+  std::vector<IOInterposeObserver*>  mCreateObservers;
+  std::vector<IOInterposeObserver*>  mReadObservers;
+  std::vector<IOInterposeObserver*>  mWriteObservers;
+  std::vector<IOInterposeObserver*>  mFSyncObservers;
+  std::vector<IOInterposeObserver*>  mStatObservers;
+  std::vector<IOInterposeObserver*>  mCloseObservers;
+  std::vector<IOInterposeObserver*>  mStageObservers;
+};
+
+class PerThreadData
+{
+public:
+  explicit PerThreadData(bool aIsMainThread = false)
+    : mIsMainThread(aIsMainThread)
+    , mIsHandlingObservation(false)
+    , mCurrentGeneration(0)
+  {
+    MOZ_COUNT_CTOR(PerThreadData);
+  }
+
+  ~PerThreadData()
+  {
+    MOZ_COUNT_DTOR(PerThreadData);
+  }
+
+  void CallObservers(IOInterposeObserver::Observation& aObservation)
+  {
+    // Prevent recursive reporting.
+    if (mIsHandlingObservation) {
+      return;
+    }
+
+    mIsHandlingObservation = true;
+    // Decide which list of observers to inform
+    std::vector<IOInterposeObserver*>* observers = nullptr;
+    switch (aObservation.ObservedOperation()) {
+      case IOInterposeObserver::OpCreateOrOpen:
+        observers = &mObserverLists->mCreateObservers;
+        break;
+      case IOInterposeObserver::OpRead:
+        observers = &mObserverLists->mReadObservers;
+        break;
+      case IOInterposeObserver::OpWrite:
+        observers = &mObserverLists->mWriteObservers;
+        break;
+      case IOInterposeObserver::OpFSync:
+        observers = &mObserverLists->mFSyncObservers;
+        break;
+      case IOInterposeObserver::OpStat:
+        observers = &mObserverLists->mStatObservers;
+        break;
+      case IOInterposeObserver::OpClose:
+        observers = &mObserverLists->mCloseObservers;
+        break;
+      case IOInterposeObserver::OpNextStage:
+        observers = &mObserverLists->mStageObservers;
+        break;
+      default: {
+        // Invalid IO operation, see documentation comment for
+        // IOInterposer::Report()
+        MOZ_ASSERT(false);
+        // Just ignore it in non-debug builds.
+        return;
+      }
+    }
+    MOZ_ASSERT(observers);
+
+    // Inform observers
+    for (auto i = observers->begin(), e = observers->end(); i != e; ++i) {
+      (*i)->Observe(aObservation);
+    }
+    mIsHandlingObservation = false;
+  }
+
+  inline uint32_t GetCurrentGeneration() const { return mCurrentGeneration; }
+
+  inline bool IsMainThread() const { return mIsMainThread; }
+
+  inline void SetObserverLists(uint32_t aNewGeneration,
+                               RefPtr<ObserverLists>& aNewLists)
+  {
+    mCurrentGeneration = aNewGeneration;
+    mObserverLists = aNewLists;
+  }
+
+  inline void ClearObserverLists()
+  {
+    if (mObserverLists) {
+      mCurrentGeneration = 0;
+      mObserverLists = nullptr;
+    }
+  }
+
+private:
+  bool                  mIsMainThread;
+  bool                  mIsHandlingObservation;
+  uint32_t              mCurrentGeneration;
+  RefPtr<ObserverLists> mObserverLists;
+};
+
+class MasterList
+{
+public:
+  MasterList()
+    : mObservedOperations(IOInterposeObserver::OpNone)
+    , mIsEnabled(true)
+  {
+    MOZ_COUNT_CTOR(MasterList);
+  }
+
+  ~MasterList()
+  {
+    MOZ_COUNT_DTOR(MasterList);
+  }
+
+  inline void Disable() { mIsEnabled = false; }
+  inline void Enable() { mIsEnabled = true; }
+
+  void Register(IOInterposeObserver::Operation aOp,
+                IOInterposeObserver* aObserver)
+  {
+    IOInterposer::AutoLock lock(mLock);
+
+    ObserverLists* newLists = nullptr;
+    if (mObserverLists) {
+      newLists = new ObserverLists(*mObserverLists);
+    } else {
+      newLists = new ObserverLists();
+    }
+    // You can register to observe multiple types of observations
+    // but you'll never be registered twice for the same observations.
+    if (aOp & IOInterposeObserver::OpCreateOrOpen &&
+        !VectorContains(newLists->mCreateObservers, aObserver)) {
+      newLists->mCreateObservers.push_back(aObserver);
+    }
+    if (aOp & IOInterposeObserver::OpRead &&
+        !VectorContains(newLists->mReadObservers, aObserver)) {
+      newLists->mReadObservers.push_back(aObserver);
+    }
+    if (aOp & IOInterposeObserver::OpWrite &&
+        !VectorContains(newLists->mWriteObservers, aObserver)) {
+      newLists->mWriteObservers.push_back(aObserver);
+    }
+    if (aOp & IOInterposeObserver::OpFSync &&
+        !VectorContains(newLists->mFSyncObservers, aObserver)) {
+      newLists->mFSyncObservers.push_back(aObserver);
+    }
+    if (aOp & IOInterposeObserver::OpStat &&
+        !VectorContains(newLists->mStatObservers, aObserver)) {
+      newLists->mStatObservers.push_back(aObserver);
+    }
+    if (aOp & IOInterposeObserver::OpClose &&
+        !VectorContains(newLists->mCloseObservers, aObserver)) {
+      newLists->mCloseObservers.push_back(aObserver);
+    }
+    if (aOp & IOInterposeObserver::OpNextStage &&
+        !VectorContains(newLists->mStageObservers, aObserver)) {
+      newLists->mStageObservers.push_back(aObserver);
+    }
+    mObserverLists = newLists;
+    mObservedOperations =
+      (IOInterposeObserver::Operation)(mObservedOperations | aOp);
+
+    mCurrentGeneration++;
+  }
+
+  void Unregister(IOInterposeObserver::Operation aOp,
+                  IOInterposeObserver* aObserver)
+  {
+    IOInterposer::AutoLock lock(mLock);
+
+    ObserverLists* newLists = nullptr;
+    if (mObserverLists) {
+      newLists = new ObserverLists(*mObserverLists);
+    } else {
+      newLists = new ObserverLists();
+    }
+
+    if (aOp & IOInterposeObserver::OpCreateOrOpen) {
+      VectorRemove(newLists->mCreateObservers, aObserver);
+      if (newLists->mCreateObservers.empty()) {
+        mObservedOperations =
+          (IOInterposeObserver::Operation)(mObservedOperations &
+                                           ~IOInterposeObserver::OpCreateOrOpen);
+      }
+    }
+    if (aOp & IOInterposeObserver::OpRead) {
+      VectorRemove(newLists->mReadObservers, aObserver);
+      if (newLists->mReadObservers.empty()) {
+        mObservedOperations =
+          (IOInterposeObserver::Operation)(mObservedOperations &
+                                           ~IOInterposeObserver::OpRead);
+      }
+    }
+    if (aOp & IOInterposeObserver::OpWrite) {
+      VectorRemove(newLists->mWriteObservers, aObserver);
+      if (newLists->mWriteObservers.empty()) {
+        mObservedOperations =
+          (IOInterposeObserver::Operation)(mObservedOperations &
+                                           ~IOInterposeObserver::OpWrite);
+      }
+    }
+    if (aOp & IOInterposeObserver::OpFSync) {
+      VectorRemove(newLists->mFSyncObservers, aObserver);
+      if (newLists->mFSyncObservers.empty()) {
+        mObservedOperations =
+          (IOInterposeObserver::Operation)(mObservedOperations &
+                                           ~IOInterposeObserver::OpFSync);
+      }
+    }
+    if (aOp & IOInterposeObserver::OpStat) {
+      VectorRemove(newLists->mStatObservers, aObserver);
+      if (newLists->mStatObservers.empty()) {
+        mObservedOperations =
+          (IOInterposeObserver::Operation)(mObservedOperations &
+                                           ~IOInterposeObserver::OpStat);
+      }
+    }
+    if (aOp & IOInterposeObserver::OpClose) {
+      VectorRemove(newLists->mCloseObservers, aObserver);
+      if (newLists->mCloseObservers.empty()) {
+        mObservedOperations =
+          (IOInterposeObserver::Operation)(mObservedOperations &
+                                           ~IOInterposeObserver::OpClose);
+      }
+    }
+    if (aOp & IOInterposeObserver::OpNextStage) {
+      VectorRemove(newLists->mStageObservers, aObserver);
+      if (newLists->mStageObservers.empty()) {
+        mObservedOperations =
+          (IOInterposeObserver::Operation)(mObservedOperations &
+                                           ~IOInterposeObserver::OpNextStage);
+      }
+    }
+    mObserverLists = newLists;
+    mCurrentGeneration++;
+  }
+
+  void Update(PerThreadData& aPtd)
+  {
+    if (mCurrentGeneration == aPtd.GetCurrentGeneration()) {
+      return;
+    }
+    // If the generation counts don't match then we need to update the current
+    // thread's observer list with the new master list.
+    IOInterposer::AutoLock lock(mLock);
+    aPtd.SetObserverLists(mCurrentGeneration, mObserverLists);
+  }
+
+  inline bool IsObservedOperation(IOInterposeObserver::Operation aOp)
+  {
+    // The quick reader may observe that no locks are being employed here,
+    // hence the result of the operations is truly undefined. However, most
+    // computers will usually return either true or false, which is good enough.
+    // It is not a problem if we occasionally report more or less IO than is
+    // actually occurring.
+    return mIsEnabled && !!(mObservedOperations & aOp);
+  }
+
+private:
+  RefPtr<ObserverLists>             mObserverLists;
+  // Note, we cannot use mozilla::Mutex here as the ObserverLists may be leaked
+  // (We want to monitor IO during shutdown). Furthermore, as we may have to
+  // unregister observers during shutdown an OffTheBooksMutex is not an option
+  // either, as its base calls into sDeadlockDetector which may be nullptr
+  // during shutdown.
+  IOInterposer::Mutex               mLock;
+  // Flags tracking which operations are being observed
+  IOInterposeObserver::Operation    mObservedOperations;
+  // Used for quickly disabling everything by IOInterposer::Disable()
+  Atomic<bool>                      mIsEnabled;
+  // Used to inform threads that the master observer list has changed
+  Atomic<uint32_t>                  mCurrentGeneration;
+};
+
+// Special observation used by IOInterposer::EnteringNextStage()
+class NextStageObservation : public IOInterposeObserver::Observation
+{
+public:
+  NextStageObservation()
+    : IOInterposeObserver::Observation(IOInterposeObserver::OpNextStage,
+                                       "IOInterposer", false)
+  {
+    mStart = TimeStamp::Now();
+    mEnd = mStart;
+  }
+};
+
+// List of observers registered
+static StaticAutoPtr<MasterList> sMasterList;
+static MOZ_THREAD_LOCAL(PerThreadData*) sThreadLocalData;
+static bool sThreadLocalDataInitialized;
+} // namespace
+
+IOInterposeObserver::Observation::Observation(Operation aOperation,
+                                              const char* aReference,
+                                              bool aShouldReport)
+  : mOperation(aOperation)
+  , mReference(aReference)
+  , mShouldReport(IOInterposer::IsObservedOperation(aOperation) &&
+                  aShouldReport)
+{
+  if (mShouldReport) {
+    mStart = TimeStamp::Now();
+  }
+}
+
+IOInterposeObserver::Observation::Observation(Operation aOperation,
+                                              const TimeStamp& aStart,
+                                              const TimeStamp& aEnd,
+                                              const char* aReference)
+  : mOperation(aOperation)
+  , mStart(aStart)
+  , mEnd(aEnd)
+  , mReference(aReference)
+  , mShouldReport(false)
+{
+}
+
+const char*
+IOInterposeObserver::Observation::ObservedOperationString() const
+{
+  switch (mOperation) {
+    case OpCreateOrOpen:
+      return "create/open";
+    case OpRead:
+      return "read";
+    case OpWrite:
+      return "write";
+    case OpFSync:
+      return "fsync";
+    case OpStat:
+      return "stat";
+    case OpClose:
+      return "close";
+    case OpNextStage:
+      return "NextStage";
+    default:
+      return "unknown";
+  }
+}
+
+void
+IOInterposeObserver::Observation::Report()
+{
+  if (mShouldReport) {
+    mEnd = TimeStamp::Now();
+    IOInterposer::Report(*this);
+  }
+}
+
+bool
+IOInterposer::Init()
+{
+  // Don't initialize twice...
+  if (sMasterList) {
+    return true;
+  }
+  if (!sThreadLocalData.init()) {
+    return false;
+  }
+  sThreadLocalDataInitialized = true;
+  bool isMainThread = true;
+  RegisterCurrentThread(isMainThread);
+  sMasterList = new MasterList();
+
+  MainThreadIOLogger::Init();
+
+  // Now we initialize the various interposers depending on platform
+  InitPoisonIOInterposer();
+  // We don't hook NSPR on Windows because PoisonIOInterposer captures a
+  // superset of the former's events.
+#if !defined(XP_WIN)
+  InitNSPRIOInterposing();
+#endif
+  return true;
+}
+
+bool
+IOInterposeObserver::IsMainThread()
+{
+  if (!sThreadLocalDataInitialized) {
+    return false;
+  }
+  PerThreadData* ptd = sThreadLocalData.get();
+  if (!ptd) {
+    return false;
+  }
+  return ptd->IsMainThread();
+}
+
+void
+IOInterposer::Clear()
+{
+  /* Clear() is a no-op on release builds so that we may continue to trap I/O
+     until process termination. In leak-checking builds, we need to shut down
+     IOInterposer so that all references are properly released. */
+#ifdef NS_FREE_PERMANENT_DATA
+  UnregisterCurrentThread();
+  sMasterList = nullptr;
+#endif
+}
+
+void
+IOInterposer::Disable()
+{
+  if (!sMasterList) {
+    return;
+  }
+  sMasterList->Disable();
+}
+
+void
+IOInterposer::Enable()
+{
+  if (!sMasterList) {
+    return;
+  }
+  sMasterList->Enable();
+}
+
+void
+IOInterposer::Report(IOInterposeObserver::Observation& aObservation)
+{
+  PerThreadData* ptd = sThreadLocalData.get();
+  if (!ptd) {
+    // In this case the current thread is not registered with IOInterposer.
+    // Alternatively we could take the slow path and just lock everything if
+    // we're not registered. That could potentially perform poorly, though.
+    return;
+  }
+
+  if (!sMasterList) {
+    // If there is no longer a master list then we should clear the local one.
+    ptd->ClearObserverLists();
+    return;
+  }
+
+  sMasterList->Update(*ptd);
+
+  // Don't try to report if there's nobody listening.
+  if (!IOInterposer::IsObservedOperation(aObservation.ObservedOperation())) {
+    return;
+  }
+
+  ptd->CallObservers(aObservation);
+}
+
+bool
+IOInterposer::IsObservedOperation(IOInterposeObserver::Operation aOp)
+{
+  return sMasterList && sMasterList->IsObservedOperation(aOp);
+}
+
+void
+IOInterposer::Register(IOInterposeObserver::Operation aOp,
+                       IOInterposeObserver* aObserver)
+{
+  MOZ_ASSERT(aObserver);
+  if (!sMasterList || !aObserver) {
+    return;
+  }
+
+  sMasterList->Register(aOp, aObserver);
+}
+
+void
+IOInterposer::Unregister(IOInterposeObserver::Operation aOp,
+                         IOInterposeObserver* aObserver)
+{
+  if (!sMasterList) {
+    return;
+  }
+
+  sMasterList->Unregister(aOp, aObserver);
+}
+
+void
+IOInterposer::RegisterCurrentThread(bool aIsMainThread)
+{
+  if (!sThreadLocalDataInitialized) {
+    return;
+  }
+  MOZ_ASSERT(!sThreadLocalData.get());
+  PerThreadData* curThreadData = new PerThreadData(aIsMainThread);
+  sThreadLocalData.set(curThreadData);
+}
+
+void
+IOInterposer::UnregisterCurrentThread()
+{
+  if (!sThreadLocalDataInitialized) {
+    return;
+  }
+  PerThreadData* curThreadData = sThreadLocalData.get();
+  MOZ_ASSERT(curThreadData);
+  sThreadLocalData.set(nullptr);
+  delete curThreadData;
+}
+
+void
+IOInterposer::EnteringNextStage()
+{
+  if (!sMasterList) {
+    return;
+  }
+  NextStageObservation observation;
+  Report(observation);
+}
+