gecko-dev/xpcom/threads/Dispatcher.cpp

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7.8 KiB
C++

/* -*- 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/Dispatcher.h"
#include "jsfriendapi.h"
#include "mozilla/AbstractThread.h"
#include "mozilla/Move.h"
#include "nsINamed.h"
#include "nsQueryObject.h"
#include "mozilla/dom/ScriptSettings.h"
#include "nsThreadUtils.h"
using namespace mozilla;
class ValidatingDispatcher::Runnable final : public mozilla::Runnable
{
public:
Runnable(already_AddRefed<nsIRunnable>&& aRunnable,
ValidatingDispatcher* aDispatcher);
NS_IMETHODIMP
GetName(nsACString& aName) override
{
mozilla::Runnable::GetName(aName);
if (aName.IsEmpty()) {
// Try to get a name from the underlying runnable.
nsCOMPtr<nsINamed> named = do_QueryInterface(mRunnable);
if (named) {
named->GetName(aName);
}
}
aName.AppendASCII("(labeled)");
return NS_OK;
}
NS_DECL_NSIRUNNABLE
private:
nsCOMPtr<nsIRunnable> mRunnable;
RefPtr<ValidatingDispatcher> mDispatcher;
};
/* DispatcherEventTarget */
namespace {
#define NS_DISPATCHEREVENTTARGET_IID \
{ 0xbf4e36c8, 0x7d04, 0x4ef4, \
{ 0xbb, 0xd8, 0x11, 0x09, 0x0a, 0xdb, 0x4d, 0xf7 } }
class DispatcherEventTarget final : public nsIEventTarget
{
RefPtr<ValidatingDispatcher> mDispatcher;
TaskCategory mCategory;
public:
NS_DECLARE_STATIC_IID_ACCESSOR(NS_DISPATCHEREVENTTARGET_IID)
DispatcherEventTarget(ValidatingDispatcher* aDispatcher, TaskCategory aCategory)
: mDispatcher(aDispatcher)
, mCategory(aCategory)
{}
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIEVENTTARGET
ValidatingDispatcher* Dispatcher() const { return mDispatcher; }
private:
~DispatcherEventTarget() {}
};
NS_DEFINE_STATIC_IID_ACCESSOR(DispatcherEventTarget, NS_DISPATCHEREVENTTARGET_IID)
} // namespace
NS_IMPL_ISUPPORTS(DispatcherEventTarget, DispatcherEventTarget, nsIEventTarget)
NS_IMETHODIMP
DispatcherEventTarget::DispatchFromScript(nsIRunnable* aRunnable, uint32_t aFlags)
{
return Dispatch(do_AddRef(aRunnable), aFlags);
}
NS_IMETHODIMP
DispatcherEventTarget::Dispatch(already_AddRefed<nsIRunnable> aRunnable, uint32_t aFlags)
{
if (NS_WARN_IF(aFlags != NS_DISPATCH_NORMAL)) {
return NS_ERROR_UNEXPECTED;
}
return mDispatcher->Dispatch(nullptr, mCategory, Move(aRunnable));
}
NS_IMETHODIMP
DispatcherEventTarget::DelayedDispatch(already_AddRefed<nsIRunnable>, uint32_t)
{
return NS_ERROR_NOT_IMPLEMENTED;
}
NS_IMETHODIMP
DispatcherEventTarget::IsOnCurrentThread(bool* aIsOnCurrentThread)
{
*aIsOnCurrentThread = NS_IsMainThread();
return NS_OK;
}
AbstractThread*
Dispatcher::AbstractMainThreadFor(TaskCategory aCategory)
{
MOZ_RELEASE_ASSERT(NS_IsMainThread());
return AbstractMainThreadForImpl(aCategory);
}
/* static */ nsresult
Dispatcher::UnlabeledDispatch(const char* aName,
TaskCategory aCategory,
already_AddRefed<nsIRunnable>&& aRunnable)
{
nsCOMPtr<nsIRunnable> runnable(aRunnable);
if (aName) {
if (nsCOMPtr<nsINamed> named = do_QueryInterface(runnable)) {
named->SetName(aName);
}
}
if (NS_IsMainThread()) {
return NS_DispatchToCurrentThread(runnable.forget());
} else {
return NS_DispatchToMainThread(runnable.forget());
}
}
ValidatingDispatcher* ValidatingDispatcher::sRunningDispatcher;
ValidatingDispatcher::ValidatingDispatcher()
: mAccessValid(false)
{
}
nsresult
ValidatingDispatcher::Dispatch(const char* aName,
TaskCategory aCategory,
already_AddRefed<nsIRunnable>&& aRunnable)
{
return LabeledDispatch(aName, aCategory, Move(aRunnable));
}
nsIEventTarget*
ValidatingDispatcher::EventTargetFor(TaskCategory aCategory) const
{
MOZ_ASSERT(aCategory != TaskCategory::Count);
MOZ_ASSERT(mEventTargets[size_t(aCategory)]);
return mEventTargets[size_t(aCategory)];
}
AbstractThread*
ValidatingDispatcher::AbstractMainThreadForImpl(TaskCategory aCategory)
{
MOZ_RELEASE_ASSERT(NS_IsMainThread());
MOZ_ASSERT(aCategory != TaskCategory::Count);
MOZ_ASSERT(mEventTargets[size_t(aCategory)]);
if (!mAbstractThreads[size_t(aCategory)]) {
mAbstractThreads[size_t(aCategory)] =
AbstractThread::CreateEventTargetWrapper(mEventTargets[size_t(aCategory)],
/* aDrainDirectTasks = */ true);
}
return mAbstractThreads[size_t(aCategory)];
}
void
ValidatingDispatcher::CreateEventTargets(bool aNeedValidation)
{
for (size_t i = 0; i < size_t(TaskCategory::Count); i++) {
TaskCategory category = static_cast<TaskCategory>(i);
if (!aNeedValidation) {
// The chrome TabGroup dispatches directly to the main thread. This means
// that we don't have to worry about cyclical references when cleaning up
// the chrome TabGroup.
mEventTargets[i] = do_GetMainThread();
} else {
mEventTargets[i] = CreateEventTargetFor(category);
}
}
}
void
ValidatingDispatcher::Shutdown(bool aXPCOMShutdown)
{
// There is a RefPtr cycle TabGroup -> DispatcherEventTarget -> TabGroup. To
// avoid leaks, we need to break the chain somewhere. We shouldn't be using
// the ThrottledEventQueue for this TabGroup when no windows belong to it,
// so it's safe to null out the queue here.
for (size_t i = 0; i < size_t(TaskCategory::Count); i++) {
mEventTargets[i] = aXPCOMShutdown ? nullptr : do_GetMainThread();
mAbstractThreads[i] = nullptr;
}
}
already_AddRefed<nsIEventTarget>
ValidatingDispatcher::CreateEventTargetFor(TaskCategory aCategory)
{
RefPtr<DispatcherEventTarget> target =
new DispatcherEventTarget(this, aCategory);
return target.forget();
}
/* static */ ValidatingDispatcher*
ValidatingDispatcher::FromEventTarget(nsIEventTarget* aEventTarget)
{
RefPtr<DispatcherEventTarget> target = do_QueryObject(aEventTarget);
if (!target) {
return nullptr;
}
return target->Dispatcher();
}
nsresult
ValidatingDispatcher::LabeledDispatch(const char* aName,
TaskCategory aCategory,
already_AddRefed<nsIRunnable>&& aRunnable)
{
nsCOMPtr<nsIRunnable> runnable(aRunnable);
if (XRE_IsContentProcess()) {
runnable = new Runnable(runnable.forget(), this);
}
return UnlabeledDispatch(aName, aCategory, runnable.forget());
}
void
ValidatingDispatcher::SetValidatingAccess(ValidationType aType)
{
sRunningDispatcher = aType == StartValidation ? this : nullptr;
mAccessValid = aType == StartValidation;
dom::AutoJSAPI jsapi;
jsapi.Init();
js::EnableAccessValidation(jsapi.cx(), !!sRunningDispatcher);
}
ValidatingDispatcher::Runnable::Runnable(already_AddRefed<nsIRunnable>&& aRunnable,
ValidatingDispatcher* aDispatcher)
: mRunnable(Move(aRunnable)),
mDispatcher(aDispatcher)
{
}
NS_IMETHODIMP
ValidatingDispatcher::Runnable::Run()
{
MOZ_RELEASE_ASSERT(NS_IsMainThread());
mDispatcher->SetValidatingAccess(StartValidation);
nsresult result = mRunnable->Run();
// The runnable's destructor can have side effects, so try to execute it in
// the scope of the TabGroup.
mRunnable = nullptr;
mDispatcher->SetValidatingAccess(EndValidation);
return result;
}
ValidatingDispatcher::AutoProcessEvent::AutoProcessEvent()
: mPrevRunningDispatcher(ValidatingDispatcher::sRunningDispatcher)
{
ValidatingDispatcher* prev = sRunningDispatcher;
if (prev) {
MOZ_ASSERT(prev->mAccessValid);
prev->SetValidatingAccess(EndValidation);
}
}
ValidatingDispatcher::AutoProcessEvent::~AutoProcessEvent()
{
MOZ_ASSERT(!sRunningDispatcher);
ValidatingDispatcher* prev = mPrevRunningDispatcher;
if (prev) {
prev->SetValidatingAccess(StartValidation);
}
}