xpcom/threads/MainThreadUtils.h

   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
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef MainThreadUtils_h_
   8 #define MainThreadUtils_h_
   9
  10 #include "mozilla/Assertions.h"
  11 #include "mozilla/ThreadSafety.h"
  12 #include "nscore.h"
  13
  14 class nsIThread;
  15
  16 /**
  17  * Get a reference to the main thread.
  18  *
  19  * @param aResult
  20  *   The resulting nsIThread object.
  21  */
  22 extern nsresult NS_GetMainThread(nsIThread** aResult);
  23
  24 #ifdef MOZILLA_INTERNAL_API
  25 bool NS_IsMainThreadTLSInitialized();
  26 extern "C" {
  27 bool NS_IsMainThread();
  28 }
  29
  30 namespace mozilla {
  31
  32 /**
  33  * A dummy static capability for the thread safety analysis which can be
  34  * required by functions and members using `MOZ_REQUIRE(sMainThreadCapability)`
  35  * and `MOZ_GUARDED_BY(sMainThreadCapability)` and asserted using
  36  * `AssertIsOnMainThread()`.
  37  *
  38  * If you want a thread-safety-analysis capability for a non-main thread,
  39  * consider using the `EventTargetCapability` type.
  40  */
  41 class MOZ_CAPABILITY("main thread") MainThreadCapability final {};
  42 constexpr MainThreadCapability sMainThreadCapability;
  43
  44 #  ifdef DEBUG
  45 void AssertIsOnMainThread() MOZ_ASSERT_CAPABILITY(sMainThreadCapability);
  46 #  else
  47 inline void AssertIsOnMainThread()
  48     MOZ_ASSERT_CAPABILITY(sMainThreadCapability) {}
  49 #  endif
  50
  51 inline void ReleaseAssertIsOnMainThread()
  52     MOZ_ASSERT_CAPABILITY(sMainThreadCapability) {
  53   MOZ_RELEASE_ASSERT(NS_IsMainThread());
  54 }
  55
  56 }  // namespace mozilla
  57
  58 #endif
  59
  60 #endif  // MainThreadUtils_h_