Add m-esr52 at 52.6.0

1 files changed, 180 insertions, 0 deletions

diff --git a/ipc/mscom/MainThreadInvoker.cpp b/ipc/mscom/MainThreadInvoker.cpp
new file mode 100644
index 000000000..cab62a727
--- /dev/null
+++ b/ipc/mscom/MainThreadInvoker.cpp
@@ -0,0 +1,180 @@
+/* -*- 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/mscom/MainThreadInvoker.h"
+
+#include "GeckoProfiler.h"
+#include "MainThreadUtils.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/HangMonitor.h"
+#include "mozilla/RefPtr.h"
+#include "nsServiceManagerUtils.h"
+#include "nsSystemInfo.h"
+#include "private/prpriv.h" // For PR_GetThreadID
+#include "WinUtils.h"
+
+// This gives us compiler intrinsics for the x86 PAUSE instruction
+#if defined(_MSC_VER)
+#include <intrin.h>
+#pragma intrinsic(_mm_pause)
+#define CPU_PAUSE() _mm_pause()
+#elif defined(__GNUC__) || defined(__clang__)
+#define CPU_PAUSE() __builtin_ia32_pause()
+#endif
+
+static bool sIsMulticore;
+
+namespace {
+
+/**
+ * SyncRunnable implements different code paths depending on whether or not
+ * we are running on a multiprocessor system. In the multiprocessor case, we
+ * leave the thread in a spin loop while waiting for the main thread to execute
+ * our runnable. Since spinning is pointless in the uniprocessor case, we block
+ * on an event that is set by the main thread once it has finished the runnable.
+ */
+class MOZ_RAII SyncRunnable
+{
+public:
+  explicit SyncRunnable(already_AddRefed<nsIRunnable>&& aRunnable)
+    : mDoneEvent(sIsMulticore ? nullptr :
+                 ::CreateEventW(nullptr, FALSE, FALSE, nullptr))
+    , mDone(false)
+    , mRunnable(aRunnable)
+  {
+    MOZ_ASSERT(sIsMulticore || mDoneEvent);
+    MOZ_ASSERT(mRunnable);
+  }
+
+  ~SyncRunnable()
+  {
+    if (mDoneEvent) {
+      ::CloseHandle(mDoneEvent);
+    }
+  }
+
+  void Run()
+  {
+    mRunnable->Run();
+
+    if (mDoneEvent) {
+      ::SetEvent(mDoneEvent);
+    } else {
+      mDone = true;
+    }
+  }
+
+  bool WaitUntilComplete()
+  {
+    if (mDoneEvent) {
+      HANDLE handles[] = {mDoneEvent,
+                          mozilla::mscom::MainThreadInvoker::GetTargetThread()};
+      DWORD waitResult = ::WaitForMultipleObjects(mozilla::ArrayLength(handles),
+                                                  handles, FALSE, INFINITE);
+      return waitResult == WAIT_OBJECT_0;
+    }
+
+    while (!mDone) {
+      // The PAUSE instruction is a hint to the CPU that we're doing a spin
+      // loop. It is a no-op on older processors that don't support it, so
+      // it is safe to use here without any CPUID checks.
+      CPU_PAUSE();
+    }
+    return true;
+  }
+
+private:
+  HANDLE                mDoneEvent;
+  mozilla::Atomic<bool> mDone;
+  nsCOMPtr<nsIRunnable> mRunnable;
+};
+
+} // anonymous namespace
+
+namespace mozilla {
+namespace mscom {
+
+HANDLE MainThreadInvoker::sMainThread = nullptr;
+
+/* static */ bool
+MainThreadInvoker::InitStatics()
+{
+  nsCOMPtr<nsIThread> mainThread;
+  nsresult rv = ::NS_GetMainThread(getter_AddRefs(mainThread));
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  PRThread* mainPrThread = nullptr;
+  rv = mainThread->GetPRThread(&mainPrThread);
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  PRUint32 tid = ::PR_GetThreadID(mainPrThread);
+  sMainThread = ::OpenThread(SYNCHRONIZE | THREAD_SET_CONTEXT, FALSE, tid);
+
+  nsCOMPtr<nsIPropertyBag2> infoService = do_GetService(NS_SYSTEMINFO_CONTRACTID);
+  if (infoService) {
+    uint32_t cpuCount;
+    nsresult rv = infoService->GetPropertyAsUint32(NS_LITERAL_STRING("cpucount"),
+                                                   &cpuCount);
+    sIsMulticore = NS_SUCCEEDED(rv) && cpuCount > 1;
+  }
+
+  return !!sMainThread;
+}
+
+MainThreadInvoker::MainThreadInvoker()
+{
+  static const bool gotStatics = InitStatics();
+  MOZ_ASSERT(gotStatics);
+}
+
+bool
+MainThreadInvoker::Invoke(already_AddRefed<nsIRunnable>&& aRunnable)
+{
+  nsCOMPtr<nsIRunnable> runnable(Move(aRunnable));
+  if (!runnable) {
+    return false;
+  }
+
+  if (NS_IsMainThread()) {
+    runnable->Run();
+    return true;
+  }
+
+  SyncRunnable syncRunnable(runnable.forget());
+
+  if (!::QueueUserAPC(&MainThreadAPC, sMainThread,
+                      reinterpret_cast<UINT_PTR>(&syncRunnable))) {
+    return false;
+  }
+
+  // We should ensure a call to NtTestAlert() is made on the main thread so
+  // that the main thread will check for APCs during event processing. If we
+  // omit this then the main thread will not check its APC queue until it is
+  // idle.
+  widget::WinUtils::SetAPCPending();
+
+  return syncRunnable.WaitUntilComplete();
+}
+
+/* static */ VOID CALLBACK
+MainThreadInvoker::MainThreadAPC(ULONG_PTR aParam)
+{
+  GeckoProfilerWakeRAII wakeProfiler;
+  mozilla::HangMonitor::NotifyActivity(mozilla::HangMonitor::kGeneralActivity);
+  MOZ_ASSERT(NS_IsMainThread());
+  auto runnable = reinterpret_cast<SyncRunnable*>(aParam);
+  runnable->Run();
+}
+
+} // namespace mscom
+} // namespace mozilla