xpcom/threads/SchedulerGroup.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
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "mozilla/SchedulerGroup.h"
   8
   9 #include <utility>
  10
  11 #include "jsfriendapi.h"
  12 #include "mozilla/Atomics.h"
  13 #include "mozilla/Telemetry.h"
  14 #include "mozilla/Unused.h"
  15 #include "mozilla/dom/DocGroup.h"
  16 #include "mozilla/dom/ScriptSettings.h"
  17 #include "nsINamed.h"
  18 #include "nsQueryObject.h"
  19 #include "nsThreadUtils.h"
  20
  21 using namespace mozilla;
  22
  23 /* static */
  24 nsresult SchedulerGroup::UnlabeledDispatch(
  25     TaskCategory aCategory, already_AddRefed<nsIRunnable>&& aRunnable) {
  26   if (NS_IsMainThread()) {
  27     return NS_DispatchToCurrentThread(std::move(aRunnable));
  28   } else {
  29     return NS_DispatchToMainThread(std::move(aRunnable));
  30   }
  31 }
  32
  33 /* static */
  34 nsresult SchedulerGroup::Dispatch(TaskCategory aCategory,
  35                                   already_AddRefed<nsIRunnable>&& aRunnable) {
  36   return LabeledDispatch(aCategory, std::move(aRunnable), nullptr);
  37 }
  38
  39 /* static */
  40 nsresult SchedulerGroup::LabeledDispatch(
  41     TaskCategory aCategory, already_AddRefed<nsIRunnable>&& aRunnable,
  42     mozilla::PerformanceCounter* aPerformanceCounter) {
  43   nsCOMPtr<nsIRunnable> runnable(aRunnable);
  44   if (XRE_IsContentProcess()) {
  45     RefPtr<Runnable> internalRunnable =
  46         new Runnable(runnable.forget(), aPerformanceCounter);
  47     return InternalUnlabeledDispatch(aCategory, internalRunnable.forget());
  48   }
  49   return UnlabeledDispatch(aCategory, runnable.forget());
  50 }
  51
  52 /*static*/
  53 nsresult SchedulerGroup::InternalUnlabeledDispatch(
  54     TaskCategory aCategory, already_AddRefed<Runnable>&& aRunnable) {
  55   if (NS_IsMainThread()) {
  56     // NS_DispatchToCurrentThread will not leak the passed in runnable
  57     // when it fails, so we don't need to do anything special.
  58     return NS_DispatchToCurrentThread(std::move(aRunnable));
  59   }
  60
  61   RefPtr<Runnable> runnable(aRunnable);
  62   nsresult rv = NS_DispatchToMainThread(do_AddRef(runnable));
  63   if (NS_FAILED(rv)) {
  64     // Dispatch failed.  This is a situation where we would have used
  65     // NS_DispatchToMainThread rather than calling into the SchedulerGroup
  66     // machinery, and the caller would be expecting to leak the nsIRunnable
  67     // originally passed in.  But because we've had to wrap things up
  68     // internally, we were going to leak the nsIRunnable *and* our Runnable
  69     // wrapper.  But there's no reason that we have to leak our Runnable
  70     // wrapper; we can just leak the wrapped nsIRunnable, and let the caller
  71     // take care of unleaking it if they need to.
  72     Unused << runnable->mRunnable.forget().take();
  73     nsrefcnt refcnt = runnable.get()->Release();
  74     MOZ_RELEASE_ASSERT(refcnt == 1, "still holding an unexpected reference!");
  75   }
  76
  77   return rv;
  78 }
  79
  80 SchedulerGroup::Runnable::Runnable(
  81     already_AddRefed<nsIRunnable>&& aRunnable,
  82     mozilla::PerformanceCounter* aPerformanceCounter)
  83     : mozilla::Runnable("SchedulerGroup::Runnable"),
  84       mRunnable(std::move(aRunnable)),
  85       mPerformanceCounter(aPerformanceCounter) {}
  86
  87 mozilla::PerformanceCounter* SchedulerGroup::Runnable::GetPerformanceCounter()
  88     const {
  89   return mPerformanceCounter;
  90 }
  91
  92 #ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
  93 NS_IMETHODIMP
  94 SchedulerGroup::Runnable::GetName(nsACString& aName) {
  95   // Try to get a name from the underlying runnable.
  96   nsCOMPtr<nsINamed> named = do_QueryInterface(mRunnable);
  97   if (named) {
  98     named->GetName(aName);
  99   }
 100   if (aName.IsEmpty()) {
 101     aName.AssignLiteral("anonymous");
 102   }
 103
 104   return NS_OK;
 105 }
 106 #endif
 107
 108 NS_IMETHODIMP
 109 SchedulerGroup::Runnable::Run() {
 110   MOZ_RELEASE_ASSERT(NS_IsMainThread());
 111   // The runnable's destructor can have side effects, so try to execute it in
 112   // the scope of the SchedulerGroup.
 113   nsCOMPtr<nsIRunnable> runnable(std::move(mRunnable));
 114   return runnable->Run();
 115 }
 116
 117 NS_IMETHODIMP
 118 SchedulerGroup::Runnable::GetPriority(uint32_t* aPriority) {
 119   *aPriority = nsIRunnablePriority::PRIORITY_NORMAL;
 120   nsCOMPtr<nsIRunnablePriority> runnablePrio = do_QueryInterface(mRunnable);
 121   return runnablePrio ? runnablePrio->GetPriority(aPriority) : NS_OK;
 122 }
 123
 124 NS_IMPL_ISUPPORTS_INHERITED(SchedulerGroup::Runnable, mozilla::Runnable,
 125                             nsIRunnablePriority, SchedulerGroup::Runnable)