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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /xpcom/threads/nsThreadUtils.h
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--xpcom/threads/nsThreadUtils.h1925
1 files changed, 1925 insertions, 0 deletions
diff --git a/xpcom/threads/nsThreadUtils.h b/xpcom/threads/nsThreadUtils.h
new file mode 100644
index 0000000000..72041da295
--- /dev/null
+++ b/xpcom/threads/nsThreadUtils.h
@@ -0,0 +1,1925 @@
+/* -*- 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/. */
+
+#ifndef nsThreadUtils_h__
+#define nsThreadUtils_h__
+
+#include <type_traits>
+#include <tuple>
+#include <utility>
+
+#include "MainThreadUtils.h"
+#include "mozilla/EventQueue.h"
+#include "mozilla/AbstractThread.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/Likely.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/ThreadLocal.h"
+#include "mozilla/TimeStamp.h"
+
+#include "nsCOMPtr.h"
+#include "nsICancelableRunnable.h"
+#include "nsIDiscardableRunnable.h"
+#include "nsIIdlePeriod.h"
+#include "nsIIdleRunnable.h"
+#include "nsINamed.h"
+#include "nsIRunnable.h"
+#include "nsIThreadManager.h"
+#include "nsITimer.h"
+#include "nsString.h"
+#include "prinrval.h"
+#include "prthread.h"
+
+class MessageLoop;
+class nsIThread;
+
+//-----------------------------------------------------------------------------
+// These methods are alternatives to the methods on nsIThreadManager, provided
+// for convenience.
+
+/**
+ * Create a new thread, and optionally provide an initial event for the thread.
+ *
+ * @param aName
+ * The name of the thread.
+ * @param aResult
+ * The resulting nsIThread object.
+ * @param aInitialEvent
+ * The initial event to run on this thread. This parameter may be null.
+ * @param aOptions
+ * Options used to configure thread creation.
+ * Options are documented in nsIThreadManager.idl.
+ *
+ * @returns NS_ERROR_INVALID_ARG
+ * Indicates that the given name is not unique.
+ */
+
+extern nsresult NS_NewNamedThread(
+ const nsACString& aName, nsIThread** aResult,
+ nsIRunnable* aInitialEvent = nullptr,
+ nsIThreadManager::ThreadCreationOptions aOptions = {});
+
+extern nsresult NS_NewNamedThread(
+ const nsACString& aName, nsIThread** aResult,
+ already_AddRefed<nsIRunnable> aInitialEvent,
+ nsIThreadManager::ThreadCreationOptions aOptions = {});
+
+template <size_t LEN>
+inline nsresult NS_NewNamedThread(
+ const char (&aName)[LEN], nsIThread** aResult,
+ already_AddRefed<nsIRunnable> aInitialEvent,
+ nsIThreadManager::ThreadCreationOptions aOptions = {}) {
+ static_assert(LEN <= 16, "Thread name must be no more than 16 characters");
+ return NS_NewNamedThread(nsDependentCString(aName, LEN - 1), aResult,
+ std::move(aInitialEvent), aOptions);
+}
+
+template <size_t LEN>
+inline nsresult NS_NewNamedThread(
+ const char (&aName)[LEN], nsIThread** aResult,
+ nsIRunnable* aInitialEvent = nullptr,
+ nsIThreadManager::ThreadCreationOptions aOptions = {}) {
+ nsCOMPtr<nsIRunnable> event = aInitialEvent;
+ static_assert(LEN <= 16, "Thread name must be no more than 16 characters");
+ return NS_NewNamedThread(nsDependentCString(aName, LEN - 1), aResult,
+ event.forget(), aOptions);
+}
+
+/**
+ * Get a reference to the current thread, creating it if it does not exist yet.
+ *
+ * @param aResult
+ * The resulting nsIThread object.
+ */
+extern nsresult NS_GetCurrentThread(nsIThread** aResult);
+
+/**
+ * Dispatch the given event to the current thread.
+ *
+ * @param aEvent
+ * The event to dispatch.
+ *
+ * @returns NS_ERROR_INVALID_ARG
+ * If event is null.
+ */
+extern nsresult NS_DispatchToCurrentThread(nsIRunnable* aEvent);
+extern nsresult NS_DispatchToCurrentThread(
+ already_AddRefed<nsIRunnable>&& aEvent);
+
+/**
+ * Dispatch the given event to the main thread.
+ *
+ * @param aEvent
+ * The event to dispatch.
+ * @param aDispatchFlags
+ * The flags to pass to the main thread's dispatch method.
+ *
+ * @returns NS_ERROR_INVALID_ARG
+ * If event is null.
+ */
+extern nsresult NS_DispatchToMainThread(
+ nsIRunnable* aEvent, uint32_t aDispatchFlags = NS_DISPATCH_NORMAL);
+extern nsresult NS_DispatchToMainThread(
+ already_AddRefed<nsIRunnable>&& aEvent,
+ uint32_t aDispatchFlags = NS_DISPATCH_NORMAL);
+
+extern nsresult NS_DelayedDispatchToCurrentThread(
+ already_AddRefed<nsIRunnable>&& aEvent, uint32_t aDelayMs);
+
+/**
+ * Dispatch the given event to the specified queue of the current thread.
+ *
+ * @param aEvent The event to dispatch.
+ * @param aQueue The event queue for the thread to use
+ *
+ * @returns NS_ERROR_INVALID_ARG
+ * If event is null.
+ * @returns NS_ERROR_UNEXPECTED
+ * If the thread is shutting down.
+ */
+extern nsresult NS_DispatchToCurrentThreadQueue(
+ already_AddRefed<nsIRunnable>&& aEvent, mozilla::EventQueuePriority aQueue);
+
+/**
+ * Dispatch the given event to the specified queue of the main thread.
+ *
+ * @param aEvent The event to dispatch.
+ * @param aQueue The event queue for the thread to use
+ *
+ * @returns NS_ERROR_INVALID_ARG
+ * If event is null.
+ * @returns NS_ERROR_UNEXPECTED
+ * If the thread is shutting down.
+ */
+extern nsresult NS_DispatchToMainThreadQueue(
+ already_AddRefed<nsIRunnable>&& aEvent, mozilla::EventQueuePriority aQueue);
+
+/**
+ * Dispatch the given event to an idle queue of the current thread.
+ *
+ * @param aEvent The event to dispatch. If the event implements
+ * nsIIdleRunnable, it will receive a call on
+ * nsIIdleRunnable::SetTimer when dispatched, with the value of
+ * aTimeout.
+ *
+ * @param aTimeout The time in milliseconds until the event should be
+ * moved from an idle queue to the regular queue, if it hasn't been
+ * executed. If aEvent is also an nsIIdleRunnable, it is expected
+ * that it should handle the timeout itself, after a call to
+ * nsIIdleRunnable::SetTimer.
+ *
+ * @param aQueue
+ * The event queue for the thread to use. Must be an idle queue
+ * (Idle or DeferredTimers)
+ *
+ * @returns NS_ERROR_INVALID_ARG
+ * If event is null.
+ * @returns NS_ERROR_UNEXPECTED
+ * If the thread is shutting down.
+ */
+extern nsresult NS_DispatchToCurrentThreadQueue(
+ already_AddRefed<nsIRunnable>&& aEvent, uint32_t aTimeout,
+ mozilla::EventQueuePriority aQueue);
+
+/**
+ * Dispatch the given event to a queue of a thread.
+ *
+ * @param aEvent The event to dispatch.
+ * @param aThread The target thread for the dispatch.
+ * @param aQueue The event queue for the thread to use.
+ *
+ * @returns NS_ERROR_INVALID_ARG
+ * If event is null.
+ * @returns NS_ERROR_UNEXPECTED
+ * If the thread is shutting down.
+ */
+extern nsresult NS_DispatchToThreadQueue(already_AddRefed<nsIRunnable>&& aEvent,
+ nsIThread* aThread,
+ mozilla::EventQueuePriority aQueue);
+
+/**
+ * Dispatch the given event to an idle queue of a thread.
+ *
+ * @param aEvent The event to dispatch. If the event implements
+ * nsIIdleRunnable, it will receive a call on
+ * nsIIdleRunnable::SetTimer when dispatched, with the value of
+ * aTimeout.
+ *
+ * @param aTimeout The time in milliseconds until the event should be
+ * moved from an idle queue to the regular queue, if it hasn't been
+ * executed. If aEvent is also an nsIIdleRunnable, it is expected
+ * that it should handle the timeout itself, after a call to
+ * nsIIdleRunnable::SetTimer.
+ *
+ * @param aThread The target thread for the dispatch.
+ *
+ * @param aQueue
+ * The event queue for the thread to use. Must be an idle queue
+ * (Idle or DeferredTimers)
+ *
+ * @returns NS_ERROR_INVALID_ARG
+ * If event is null.
+ * @returns NS_ERROR_UNEXPECTED
+ * If the thread is shutting down.
+ */
+extern nsresult NS_DispatchToThreadQueue(already_AddRefed<nsIRunnable>&& aEvent,
+ uint32_t aTimeout, nsIThread* aThread,
+ mozilla::EventQueuePriority aQueue);
+
+#ifndef XPCOM_GLUE_AVOID_NSPR
+/**
+ * Process all pending events for the given thread before returning. This
+ * method simply calls ProcessNextEvent on the thread while HasPendingEvents
+ * continues to return true and the time spent in NS_ProcessPendingEvents
+ * does not exceed the given timeout value.
+ *
+ * @param aThread
+ * The thread object for which to process pending events. If null, then
+ * events will be processed for the current thread.
+ * @param aTimeout
+ * The maximum number of milliseconds to spend processing pending events.
+ * Events are not pre-empted to honor this timeout. Rather, the timeout
+ * value is simply used to determine whether or not to process another event.
+ * Pass PR_INTERVAL_NO_TIMEOUT to specify no timeout.
+ */
+extern nsresult NS_ProcessPendingEvents(
+ nsIThread* aThread, PRIntervalTime aTimeout = PR_INTERVAL_NO_TIMEOUT);
+#endif
+
+/**
+ * Shortcut for nsIThread::HasPendingEvents.
+ *
+ * It is an error to call this function when the given thread is not the
+ * current thread. This function will return false if called from some
+ * other thread.
+ *
+ * @param aThread
+ * The current thread or null.
+ *
+ * @returns
+ * A boolean value that if "true" indicates that there are pending events
+ * in the current thread's event queue.
+ */
+extern bool NS_HasPendingEvents(nsIThread* aThread = nullptr);
+
+/**
+ * Shortcut for nsIThread::ProcessNextEvent.
+ *
+ * It is an error to call this function when the given thread is not the
+ * current thread. This function will simply return false if called
+ * from some other thread.
+ *
+ * @param aThread
+ * The current thread or null.
+ * @param aMayWait
+ * A boolean parameter that if "true" indicates that the method may block
+ * the calling thread to wait for a pending event.
+ *
+ * @returns
+ * A boolean value that if "true" indicates that an event from the current
+ * thread's event queue was processed.
+ */
+extern bool NS_ProcessNextEvent(nsIThread* aThread = nullptr,
+ bool aMayWait = true);
+
+/**
+ * Returns true if we're in the compositor thread.
+ *
+ * We declare this here because the headers required to invoke
+ * CompositorThreadHolder::IsInCompositorThread() also pull in a bunch of system
+ * headers that #define various tokens in a way that can break the build.
+ */
+extern bool NS_IsInCompositorThread();
+
+extern bool NS_IsInCanvasThreadOrWorker();
+
+extern bool NS_IsInVRThread();
+
+//-----------------------------------------------------------------------------
+// Helpers that work with nsCOMPtr:
+
+inline already_AddRefed<nsIThread> do_GetCurrentThread() {
+ nsIThread* thread = nullptr;
+ NS_GetCurrentThread(&thread);
+ return already_AddRefed<nsIThread>(thread);
+}
+
+inline already_AddRefed<nsIThread> do_GetMainThread() {
+ nsIThread* thread = nullptr;
+ NS_GetMainThread(&thread);
+ return already_AddRefed<nsIThread>(thread);
+}
+
+//-----------------------------------------------------------------------------
+
+// Fast access to the current thread. Will create an nsIThread if one does not
+// exist already! Do not release the returned pointer! If you want to use this
+// pointer from some other thread, then you will need to AddRef it. Otherwise,
+// you should only consider this pointer valid from code running on the current
+// thread.
+extern nsIThread* NS_GetCurrentThread();
+
+// Exactly the same as NS_GetCurrentThread, except it will not create an
+// nsThread if one does not exist yet. This is useful in cases where you have
+// code that runs on threads that may or may not not be driven by an nsThread
+// event loop, and wish to avoid inadvertently creating a superfluous nsThread.
+extern nsIThread* NS_GetCurrentThreadNoCreate();
+
+/**
+ * Set the name of the current thread. Prefer this function over
+ * PR_SetCurrentThreadName() if possible. The name will also be included in the
+ * crash report.
+ *
+ * @param aName
+ * Name of the thread. A C language null-terminated string.
+ */
+extern void NS_SetCurrentThreadName(const char* aName);
+
+//-----------------------------------------------------------------------------
+
+#ifndef XPCOM_GLUE_AVOID_NSPR
+
+namespace mozilla {
+
+// This class is designed to be subclassed.
+class IdlePeriod : public nsIIdlePeriod {
+ public:
+ NS_DECL_THREADSAFE_ISUPPORTS
+ NS_DECL_NSIIDLEPERIOD
+
+ IdlePeriod() = default;
+
+ protected:
+ virtual ~IdlePeriod() = default;
+
+ private:
+ IdlePeriod(const IdlePeriod&) = delete;
+ IdlePeriod& operator=(const IdlePeriod&) = delete;
+ IdlePeriod& operator=(const IdlePeriod&&) = delete;
+};
+
+// Cancelable runnable methods implement nsICancelableRunnable, and
+// Idle and IdleWithTimer also nsIIdleRunnable.
+enum class RunnableKind { Standard, Cancelable, Idle, IdleWithTimer };
+
+// Implementing nsINamed on Runnable bloats vtables for the hundreds of
+// Runnable subclasses that we have, so we want to avoid that overhead
+// when we're not using nsINamed for anything.
+# ifndef RELEASE_OR_BETA
+# define MOZ_COLLECTING_RUNNABLE_TELEMETRY
+# endif
+
+// This class is designed to be subclassed.
+class Runnable : public nsIRunnable
+# ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
+ ,
+ public nsINamed
+# endif
+{
+ public:
+ NS_DECL_THREADSAFE_ISUPPORTS
+ NS_DECL_NSIRUNNABLE
+# ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
+ NS_DECL_NSINAMED
+# endif
+
+ Runnable() = delete;
+
+# ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
+ explicit Runnable(const char* aName) : mName(aName) {}
+# else
+ explicit Runnable(const char* aName) {}
+# endif
+
+ protected:
+ virtual ~Runnable() = default;
+
+# ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
+ const char* mName = nullptr;
+# endif
+
+ private:
+ Runnable(const Runnable&) = delete;
+ Runnable& operator=(const Runnable&) = delete;
+ Runnable& operator=(const Runnable&&) = delete;
+};
+
+// This is a base class for tasks that might not be run, such as those that may
+// be dispatched to workers.
+// The owner of an event target will call either Run() or OnDiscard()
+// exactly once.
+// Derived classes should override Run(). An OnDiscard() override may
+// provide cleanup when Run() will not be called.
+class DiscardableRunnable : public Runnable, public nsIDiscardableRunnable {
+ public:
+ NS_DECL_ISUPPORTS_INHERITED
+ // nsIDiscardableRunnable
+ void OnDiscard() override {}
+
+ DiscardableRunnable() = delete;
+ explicit DiscardableRunnable(const char* aName) : Runnable(aName) {}
+
+ protected:
+ virtual ~DiscardableRunnable() = default;
+
+ private:
+ DiscardableRunnable(const DiscardableRunnable&) = delete;
+ DiscardableRunnable& operator=(const DiscardableRunnable&) = delete;
+ DiscardableRunnable& operator=(const DiscardableRunnable&&) = delete;
+};
+
+// This class is designed to be subclassed.
+// Derived classes should override Run() and Cancel() to provide that
+// calling Run() after Cancel() is a no-op.
+class CancelableRunnable : public DiscardableRunnable,
+ public nsICancelableRunnable {
+ public:
+ NS_DECL_ISUPPORTS_INHERITED
+ // nsIDiscardableRunnable
+ void OnDiscard() override;
+ // nsICancelableRunnable
+ virtual nsresult Cancel() override = 0;
+
+ CancelableRunnable() = delete;
+ explicit CancelableRunnable(const char* aName) : DiscardableRunnable(aName) {}
+
+ protected:
+ virtual ~CancelableRunnable() = default;
+
+ private:
+ CancelableRunnable(const CancelableRunnable&) = delete;
+ CancelableRunnable& operator=(const CancelableRunnable&) = delete;
+ CancelableRunnable& operator=(const CancelableRunnable&&) = delete;
+};
+
+// This class is designed to be subclassed.
+class IdleRunnable : public DiscardableRunnable, public nsIIdleRunnable {
+ public:
+ NS_DECL_ISUPPORTS_INHERITED
+
+ explicit IdleRunnable(const char* aName) : DiscardableRunnable(aName) {}
+
+ protected:
+ virtual ~IdleRunnable() = default;
+
+ private:
+ IdleRunnable(const IdleRunnable&) = delete;
+ IdleRunnable& operator=(const IdleRunnable&) = delete;
+ IdleRunnable& operator=(const IdleRunnable&&) = delete;
+};
+
+// This class is designed to be subclassed.
+class CancelableIdleRunnable : public CancelableRunnable,
+ public nsIIdleRunnable {
+ public:
+ NS_DECL_ISUPPORTS_INHERITED
+
+ CancelableIdleRunnable() : CancelableRunnable("CancelableIdleRunnable") {}
+ explicit CancelableIdleRunnable(const char* aName)
+ : CancelableRunnable(aName) {}
+
+ protected:
+ virtual ~CancelableIdleRunnable() = default;
+
+ private:
+ CancelableIdleRunnable(const CancelableIdleRunnable&) = delete;
+ CancelableIdleRunnable& operator=(const CancelableIdleRunnable&) = delete;
+ CancelableIdleRunnable& operator=(const CancelableIdleRunnable&&) = delete;
+};
+
+// This class is designed to be a wrapper of a real runnable to support event
+// prioritizable.
+class PrioritizableRunnable : public Runnable, public nsIRunnablePriority {
+ public:
+ PrioritizableRunnable(already_AddRefed<nsIRunnable>&& aRunnable,
+ uint32_t aPriority);
+
+# ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
+ NS_IMETHOD GetName(nsACString& aName) override;
+# endif
+
+ NS_DECL_ISUPPORTS_INHERITED
+ NS_DECL_NSIRUNNABLE
+ NS_DECL_NSIRUNNABLEPRIORITY
+
+ protected:
+ virtual ~PrioritizableRunnable() = default;
+
+ nsCOMPtr<nsIRunnable> mRunnable;
+ uint32_t mPriority;
+};
+
+class PrioritizableCancelableRunnable : public CancelableRunnable,
+ public nsIRunnablePriority {
+ public:
+ PrioritizableCancelableRunnable(uint32_t aPriority, const char* aName)
+ : CancelableRunnable(aName), mPriority(aPriority) {}
+
+ NS_DECL_ISUPPORTS_INHERITED
+ NS_DECL_NSIRUNNABLEPRIORITY
+
+ protected:
+ virtual ~PrioritizableCancelableRunnable() = default;
+
+ const uint32_t mPriority;
+};
+
+extern already_AddRefed<nsIRunnable> CreateRenderBlockingRunnable(
+ already_AddRefed<nsIRunnable>&& aRunnable);
+
+namespace detail {
+
+// An event that can be used to call a C++11 functions or function objects,
+// including lambdas. The function must have no required arguments, and must
+// return void.
+template <typename StoredFunction>
+class RunnableFunction : public Runnable {
+ public:
+ template <typename F>
+ explicit RunnableFunction(const char* aName, F&& aFunction)
+ : Runnable(aName), mFunction(std::forward<F>(aFunction)) {}
+
+ NS_IMETHOD Run() override {
+ static_assert(std::is_void_v<decltype(mFunction())>,
+ "The lambda must return void!");
+ mFunction();
+ return NS_OK;
+ }
+
+ private:
+ StoredFunction mFunction;
+};
+
+// Type alias for NS_NewRunnableFunction
+template <typename Function>
+using RunnableFunctionImpl =
+ // Make sure we store a non-reference in nsRunnableFunction.
+ typename detail::RunnableFunction<std::remove_reference_t<Function>>;
+} // namespace detail
+
+namespace detail {
+
+template <typename CVRemoved>
+struct IsRefcountedSmartPointerHelper : std::false_type {};
+
+template <typename Pointee>
+struct IsRefcountedSmartPointerHelper<RefPtr<Pointee>> : std::true_type {};
+
+template <typename Pointee>
+struct IsRefcountedSmartPointerHelper<nsCOMPtr<Pointee>> : std::true_type {};
+
+} // namespace detail
+
+template <typename T>
+struct IsRefcountedSmartPointer
+ : detail::IsRefcountedSmartPointerHelper<std::remove_cv_t<T>> {};
+
+namespace detail {
+
+template <typename T, typename CVRemoved>
+struct RemoveSmartPointerHelper {
+ typedef T Type;
+};
+
+template <typename T, typename Pointee>
+struct RemoveSmartPointerHelper<T, RefPtr<Pointee>> {
+ typedef Pointee Type;
+};
+
+template <typename T, typename Pointee>
+struct RemoveSmartPointerHelper<T, nsCOMPtr<Pointee>> {
+ typedef Pointee Type;
+};
+
+} // namespace detail
+
+template <typename T>
+struct RemoveSmartPointer
+ : detail::RemoveSmartPointerHelper<T, std::remove_cv_t<T>> {};
+
+namespace detail {
+
+template <typename T, typename CVRemoved>
+struct RemoveRawOrSmartPointerHelper {
+ typedef T Type;
+};
+
+template <typename T, typename Pointee>
+struct RemoveRawOrSmartPointerHelper<T, Pointee*> {
+ typedef Pointee Type;
+};
+
+template <typename T, typename Pointee>
+struct RemoveRawOrSmartPointerHelper<T, RefPtr<Pointee>> {
+ typedef Pointee Type;
+};
+
+template <typename T, typename Pointee>
+struct RemoveRawOrSmartPointerHelper<T, nsCOMPtr<Pointee>> {
+ typedef Pointee Type;
+};
+
+} // namespace detail
+
+template <typename T>
+struct RemoveRawOrSmartPointer
+ : detail::RemoveRawOrSmartPointerHelper<T, std::remove_cv_t<T>> {};
+
+} // namespace mozilla
+
+inline nsISupports* ToSupports(mozilla::Runnable* p) {
+ return static_cast<nsIRunnable*>(p);
+}
+
+template <typename Function>
+already_AddRefed<mozilla::Runnable> NS_NewRunnableFunction(
+ const char* aName, Function&& aFunction) {
+ // We store a non-reference in RunnableFunction, but still forward aFunction
+ // to move if possible.
+ return do_AddRef(new mozilla::detail::RunnableFunctionImpl<Function>(
+ aName, std::forward<Function>(aFunction)));
+}
+
+// Creates a new object implementing nsIRunnable and nsICancelableRunnable,
+// which runs a given function on Run and clears the stored function object on a
+// call to `Cancel` (and thus destroys all objects it holds).
+template <typename Function>
+already_AddRefed<mozilla::CancelableRunnable> NS_NewCancelableRunnableFunction(
+ const char* aName, Function&& aFunc) {
+ class FuncCancelableRunnable final : public mozilla::CancelableRunnable {
+ public:
+ static_assert(
+ std::is_void_v<
+ decltype(std::declval<std::remove_reference_t<Function>>()())>);
+
+ NS_INLINE_DECL_REFCOUNTING_INHERITED(FuncCancelableRunnable,
+ CancelableRunnable)
+
+ explicit FuncCancelableRunnable(const char* aName, Function&& aFunc)
+ : CancelableRunnable{aName},
+ mFunc{mozilla::Some(std::forward<Function>(aFunc))} {}
+
+ NS_IMETHOD Run() override {
+ if (mFunc) {
+ (*mFunc)();
+ }
+
+ return NS_OK;
+ }
+
+ nsresult Cancel() override {
+ mFunc.reset();
+ return NS_OK;
+ }
+
+ private:
+ ~FuncCancelableRunnable() = default;
+
+ mozilla::Maybe<std::remove_reference_t<Function>> mFunc;
+ };
+
+ return mozilla::MakeAndAddRef<FuncCancelableRunnable>(
+ aName, std::forward<Function>(aFunc));
+}
+
+namespace mozilla {
+namespace detail {
+
+template <RunnableKind Kind>
+class TimerBehaviour {
+ public:
+ nsITimer* GetTimer() { return nullptr; }
+ void CancelTimer() {}
+
+ protected:
+ ~TimerBehaviour() = default;
+};
+
+template <>
+class TimerBehaviour<RunnableKind::IdleWithTimer> {
+ public:
+ nsITimer* GetTimer() {
+ if (!mTimer) {
+ mTimer = NS_NewTimer();
+ }
+
+ return mTimer;
+ }
+
+ void CancelTimer() {
+ if (mTimer) {
+ mTimer->Cancel();
+ }
+ }
+
+ protected:
+ ~TimerBehaviour() { CancelTimer(); }
+
+ private:
+ nsCOMPtr<nsITimer> mTimer;
+};
+
+} // namespace detail
+} // namespace mozilla
+
+// An event that can be used to call a method on a class. The class type must
+// support reference counting. This event supports Revoke for use
+// with nsRevocableEventPtr.
+template <class ClassType, typename ReturnType = void, bool Owning = true,
+ mozilla::RunnableKind Kind = mozilla::RunnableKind::Standard>
+class nsRunnableMethod
+ : public std::conditional_t<
+ Kind == mozilla::RunnableKind::Standard, mozilla::Runnable,
+ std::conditional_t<Kind == mozilla::RunnableKind::Cancelable,
+ mozilla::CancelableRunnable,
+ mozilla::CancelableIdleRunnable>>,
+ protected mozilla::detail::TimerBehaviour<Kind> {
+ using BaseType = std::conditional_t<
+ Kind == mozilla::RunnableKind::Standard, mozilla::Runnable,
+ std::conditional_t<Kind == mozilla::RunnableKind::Cancelable,
+ mozilla::CancelableRunnable,
+ mozilla::CancelableIdleRunnable>>;
+
+ public:
+ nsRunnableMethod(const char* aName) : BaseType(aName) {}
+
+ virtual void Revoke() = 0;
+
+ // These ReturnTypeEnforcer classes disallow return types that
+ // we know are not safe. The default ReturnTypeEnforcer compiles just fine but
+ // already_AddRefed will not.
+ template <typename OtherReturnType>
+ class ReturnTypeEnforcer {
+ public:
+ typedef int ReturnTypeIsSafe;
+ };
+
+ template <class T>
+ class ReturnTypeEnforcer<already_AddRefed<T>> {
+ // No ReturnTypeIsSafe makes this illegal!
+ };
+
+ // Make sure this return type is safe.
+ typedef typename ReturnTypeEnforcer<ReturnType>::ReturnTypeIsSafe check;
+};
+
+template <class ClassType, bool Owning>
+struct nsRunnableMethodReceiver {
+ RefPtr<ClassType> mObj;
+ explicit nsRunnableMethodReceiver(ClassType* aObj) : mObj(aObj) {}
+ explicit nsRunnableMethodReceiver(RefPtr<ClassType>&& aObj)
+ : mObj(std::move(aObj)) {}
+ ~nsRunnableMethodReceiver() { Revoke(); }
+ ClassType* Get() const { return mObj.get(); }
+ void Revoke() { mObj = nullptr; }
+};
+
+template <class ClassType>
+struct nsRunnableMethodReceiver<ClassType, false> {
+ ClassType* MOZ_NON_OWNING_REF mObj;
+ explicit nsRunnableMethodReceiver(ClassType* aObj) : mObj(aObj) {}
+ ClassType* Get() const { return mObj; }
+ void Revoke() { mObj = nullptr; }
+};
+
+static inline constexpr bool IsIdle(mozilla::RunnableKind aKind) {
+ return aKind == mozilla::RunnableKind::Idle ||
+ aKind == mozilla::RunnableKind::IdleWithTimer;
+}
+
+template <typename PtrType, typename Method, bool Owning,
+ mozilla::RunnableKind Kind>
+struct nsRunnableMethodTraits;
+
+template <typename PtrType, class C, typename R, bool Owning,
+ mozilla::RunnableKind Kind, typename... As>
+struct nsRunnableMethodTraits<PtrType, R (C::*)(As...), Owning, Kind> {
+ typedef typename mozilla::RemoveRawOrSmartPointer<PtrType>::Type class_type;
+ static_assert(std::is_base_of<C, class_type>::value,
+ "Stored class must inherit from method's class");
+ typedef R return_type;
+ typedef nsRunnableMethod<C, R, Owning, Kind> base_type;
+ static const bool can_cancel = Kind == mozilla::RunnableKind::Cancelable;
+};
+
+template <typename PtrType, class C, typename R, bool Owning,
+ mozilla::RunnableKind Kind, typename... As>
+struct nsRunnableMethodTraits<PtrType, R (C::*)(As...) const, Owning, Kind> {
+ typedef const typename mozilla::RemoveRawOrSmartPointer<PtrType>::Type
+ class_type;
+ static_assert(std::is_base_of<C, class_type>::value,
+ "Stored class must inherit from method's class");
+ typedef R return_type;
+ typedef nsRunnableMethod<C, R, Owning, Kind> base_type;
+ static const bool can_cancel = Kind == mozilla::RunnableKind::Cancelable;
+};
+
+# ifdef NS_HAVE_STDCALL
+template <typename PtrType, class C, typename R, bool Owning,
+ mozilla::RunnableKind Kind, typename... As>
+struct nsRunnableMethodTraits<PtrType, R (__stdcall C::*)(As...), Owning,
+ Kind> {
+ typedef typename mozilla::RemoveRawOrSmartPointer<PtrType>::Type class_type;
+ static_assert(std::is_base_of<C, class_type>::value,
+ "Stored class must inherit from method's class");
+ typedef R return_type;
+ typedef nsRunnableMethod<C, R, Owning, Kind> base_type;
+ static const bool can_cancel = Kind == mozilla::RunnableKind::Cancelable;
+};
+
+template <typename PtrType, class C, typename R, bool Owning,
+ mozilla::RunnableKind Kind>
+struct nsRunnableMethodTraits<PtrType, R (NS_STDCALL C::*)(), Owning, Kind> {
+ typedef typename mozilla::RemoveRawOrSmartPointer<PtrType>::Type class_type;
+ static_assert(std::is_base_of<C, class_type>::value,
+ "Stored class must inherit from method's class");
+ typedef R return_type;
+ typedef nsRunnableMethod<C, R, Owning, Kind> base_type;
+ static const bool can_cancel = Kind == mozilla::RunnableKind::Cancelable;
+};
+
+template <typename PtrType, class C, typename R, bool Owning,
+ mozilla::RunnableKind Kind, typename... As>
+struct nsRunnableMethodTraits<PtrType, R (__stdcall C::*)(As...) const, Owning,
+ Kind> {
+ typedef const typename mozilla::RemoveRawOrSmartPointer<PtrType>::Type
+ class_type;
+ static_assert(std::is_base_of<C, class_type>::value,
+ "Stored class must inherit from method's class");
+ typedef R return_type;
+ typedef nsRunnableMethod<C, R, Owning, Kind> base_type;
+ static const bool can_cancel = Kind == mozilla::RunnableKind::Cancelable;
+};
+
+template <typename PtrType, class C, typename R, bool Owning,
+ mozilla::RunnableKind Kind>
+struct nsRunnableMethodTraits<PtrType, R (NS_STDCALL C::*)() const, Owning,
+ Kind> {
+ typedef const typename mozilla::RemoveRawOrSmartPointer<PtrType>::Type
+ class_type;
+ static_assert(std::is_base_of<C, class_type>::value,
+ "Stored class must inherit from method's class");
+ typedef R return_type;
+ typedef nsRunnableMethod<C, R, Owning, Kind> base_type;
+ static const bool can_cancel = Kind == mozilla::RunnableKind::Cancelable;
+};
+# endif
+
+// IsParameterStorageClass<T>::value is true if T is a parameter-storage class
+// that will be recognized by NS_New[NonOwning]RunnableMethodWithArg[s] to
+// force a specific storage&passing strategy (instead of inferring one,
+// see ParameterStorage).
+// When creating a new storage class, add a specialization for it to be
+// recognized.
+template <typename T>
+struct IsParameterStorageClass : public std::false_type {};
+
+// StoreXPassByY structs used to inform nsRunnableMethodArguments how to
+// store arguments, and how to pass them to the target method.
+
+template <typename T>
+struct StoreCopyPassByValue {
+ using stored_type = std::decay_t<T>;
+ typedef stored_type passed_type;
+ stored_type m;
+ template <typename A>
+ MOZ_IMPLICIT StoreCopyPassByValue(A&& a) : m(std::forward<A>(a)) {}
+ passed_type PassAsParameter() { return m; }
+};
+template <typename S>
+struct IsParameterStorageClass<StoreCopyPassByValue<S>>
+ : public std::true_type {};
+
+template <typename T>
+struct StoreCopyPassByConstLRef {
+ using stored_type = std::decay_t<T>;
+ typedef const stored_type& passed_type;
+ stored_type m;
+ template <typename A>
+ MOZ_IMPLICIT StoreCopyPassByConstLRef(A&& a) : m(std::forward<A>(a)) {}
+ passed_type PassAsParameter() { return m; }
+};
+template <typename S>
+struct IsParameterStorageClass<StoreCopyPassByConstLRef<S>>
+ : public std::true_type {};
+
+template <typename T>
+struct StoreCopyPassByLRef {
+ using stored_type = std::decay_t<T>;
+ typedef stored_type& passed_type;
+ stored_type m;
+ template <typename A>
+ MOZ_IMPLICIT StoreCopyPassByLRef(A&& a) : m(std::forward<A>(a)) {}
+ passed_type PassAsParameter() { return m; }
+};
+template <typename S>
+struct IsParameterStorageClass<StoreCopyPassByLRef<S>> : public std::true_type {
+};
+
+template <typename T>
+struct StoreCopyPassByRRef {
+ using stored_type = std::decay_t<T>;
+ typedef stored_type&& passed_type;
+ stored_type m;
+ template <typename A>
+ MOZ_IMPLICIT StoreCopyPassByRRef(A&& a) : m(std::forward<A>(a)) {}
+ passed_type PassAsParameter() { return std::move(m); }
+};
+template <typename S>
+struct IsParameterStorageClass<StoreCopyPassByRRef<S>> : public std::true_type {
+};
+
+template <typename T>
+struct StoreRefPassByLRef {
+ typedef T& stored_type;
+ typedef T& passed_type;
+ stored_type m;
+ template <typename A>
+ MOZ_IMPLICIT StoreRefPassByLRef(A& a) : m(a) {}
+ passed_type PassAsParameter() { return m; }
+};
+template <typename S>
+struct IsParameterStorageClass<StoreRefPassByLRef<S>> : public std::true_type {
+};
+
+template <typename T>
+struct StoreConstRefPassByConstLRef {
+ typedef const T& stored_type;
+ typedef const T& passed_type;
+ stored_type m;
+ template <typename A>
+ MOZ_IMPLICIT StoreConstRefPassByConstLRef(const A& a) : m(a) {}
+ passed_type PassAsParameter() { return m; }
+};
+template <typename S>
+struct IsParameterStorageClass<StoreConstRefPassByConstLRef<S>>
+ : public std::true_type {};
+
+template <typename T>
+struct StoreRefPtrPassByPtr {
+ typedef RefPtr<T> stored_type;
+ typedef T* passed_type;
+ stored_type m;
+ template <typename A>
+ MOZ_IMPLICIT StoreRefPtrPassByPtr(A&& a) : m(std::forward<A>(a)) {}
+ passed_type PassAsParameter() { return m.get(); }
+};
+template <typename S>
+struct IsParameterStorageClass<StoreRefPtrPassByPtr<S>>
+ : public std::true_type {};
+
+template <typename T>
+struct StorePtrPassByPtr {
+ typedef T* stored_type;
+ typedef T* passed_type;
+ stored_type m;
+ template <typename A>
+ MOZ_IMPLICIT StorePtrPassByPtr(A a) : m(a) {}
+ passed_type PassAsParameter() { return m; }
+};
+template <typename S>
+struct IsParameterStorageClass<StorePtrPassByPtr<S>> : public std::true_type {};
+
+template <typename T>
+struct StoreConstPtrPassByConstPtr {
+ typedef const T* stored_type;
+ typedef const T* passed_type;
+ stored_type m;
+ template <typename A>
+ MOZ_IMPLICIT StoreConstPtrPassByConstPtr(A a) : m(a) {}
+ passed_type PassAsParameter() { return m; }
+};
+template <typename S>
+struct IsParameterStorageClass<StoreConstPtrPassByConstPtr<S>>
+ : public std::true_type {};
+
+template <typename T>
+struct StoreCopyPassByConstPtr {
+ typedef T stored_type;
+ typedef const T* passed_type;
+ stored_type m;
+ template <typename A>
+ MOZ_IMPLICIT StoreCopyPassByConstPtr(A&& a) : m(std::forward<A>(a)) {}
+ passed_type PassAsParameter() { return &m; }
+};
+template <typename S>
+struct IsParameterStorageClass<StoreCopyPassByConstPtr<S>>
+ : public std::true_type {};
+
+template <typename T>
+struct StoreCopyPassByPtr {
+ typedef T stored_type;
+ typedef T* passed_type;
+ stored_type m;
+ template <typename A>
+ MOZ_IMPLICIT StoreCopyPassByPtr(A&& a) : m(std::forward<A>(a)) {}
+ passed_type PassAsParameter() { return &m; }
+};
+template <typename S>
+struct IsParameterStorageClass<StoreCopyPassByPtr<S>> : public std::true_type {
+};
+
+namespace detail {
+
+template <typename>
+struct SFINAE1True : std::true_type {};
+
+template <class T>
+static auto HasRefCountMethodsTest(int)
+ -> SFINAE1True<decltype(std::declval<T>().AddRef(),
+ std::declval<T>().Release())>;
+template <class>
+static auto HasRefCountMethodsTest(long) -> std::false_type;
+
+template <class T>
+struct HasRefCountMethods : decltype(HasRefCountMethodsTest<T>(0)) {};
+
+template <typename TWithoutPointer>
+struct NonnsISupportsPointerStorageClass
+ : std::conditional<
+ std::is_const_v<TWithoutPointer>,
+ StoreConstPtrPassByConstPtr<std::remove_const_t<TWithoutPointer>>,
+ StorePtrPassByPtr<TWithoutPointer>> {
+ using Type = typename NonnsISupportsPointerStorageClass::conditional::type;
+};
+
+template <typename TWithoutPointer>
+struct PointerStorageClass
+ : std::conditional<
+ HasRefCountMethods<TWithoutPointer>::value,
+ StoreRefPtrPassByPtr<TWithoutPointer>,
+ typename NonnsISupportsPointerStorageClass<TWithoutPointer>::Type> {
+ using Type = typename PointerStorageClass::conditional::type;
+};
+
+template <typename TWithoutRef>
+struct LValueReferenceStorageClass
+ : std::conditional<
+ std::is_const_v<TWithoutRef>,
+ StoreConstRefPassByConstLRef<std::remove_const_t<TWithoutRef>>,
+ StoreRefPassByLRef<TWithoutRef>> {
+ using Type = typename LValueReferenceStorageClass::conditional::type;
+};
+
+template <typename T>
+struct SmartPointerStorageClass
+ : std::conditional<
+ mozilla::IsRefcountedSmartPointer<T>::value,
+ StoreRefPtrPassByPtr<typename mozilla::RemoveSmartPointer<T>::Type>,
+ StoreCopyPassByConstLRef<T>> {
+ using Type = typename SmartPointerStorageClass::conditional::type;
+};
+
+template <typename T>
+struct NonLValueReferenceStorageClass
+ : std::conditional<std::is_rvalue_reference_v<T>,
+ StoreCopyPassByRRef<std::remove_reference_t<T>>,
+ typename SmartPointerStorageClass<T>::Type> {
+ using Type = typename NonLValueReferenceStorageClass::conditional::type;
+};
+
+template <typename T>
+struct NonPointerStorageClass
+ : std::conditional<std::is_lvalue_reference_v<T>,
+ typename LValueReferenceStorageClass<
+ std::remove_reference_t<T>>::Type,
+ typename NonLValueReferenceStorageClass<T>::Type> {
+ using Type = typename NonPointerStorageClass::conditional::type;
+};
+
+template <typename T>
+struct NonParameterStorageClass
+ : std::conditional<
+ std::is_pointer_v<T>,
+ typename PointerStorageClass<std::remove_pointer_t<T>>::Type,
+ typename NonPointerStorageClass<T>::Type> {
+ using Type = typename NonParameterStorageClass::conditional::type;
+};
+
+// Choose storage&passing strategy based on preferred storage type:
+// - If IsParameterStorageClass<T>::value is true, use as-is.
+// - RC* -> StoreRefPtrPassByPtr<RC> :Store RefPtr<RC>, pass RC*
+// ^^ RC quacks like a ref-counted type (i.e., has AddRef and Release methods)
+// - const T* -> StoreConstPtrPassByConstPtr<T> :Store const T*, pass const T*
+// - T* -> StorePtrPassByPtr<T> :Store T*, pass T*.
+// - const T& -> StoreConstRefPassByConstLRef<T>:Store const T&, pass const T&.
+// - T& -> StoreRefPassByLRef<T> :Store T&, pass T&.
+// - T&& -> StoreCopyPassByRRef<T> :Store T, pass std::move(T).
+// - RefPtr<T>, nsCOMPtr<T>
+// -> StoreRefPtrPassByPtr<T> :Store RefPtr<T>, pass T*
+// - Other T -> StoreCopyPassByConstLRef<T> :Store T, pass const T&.
+// Other available explicit options:
+// - StoreCopyPassByValue<T> :Store T, pass T.
+// - StoreCopyPassByLRef<T> :Store T, pass T& (of copy!)
+// - StoreCopyPassByConstPtr<T> :Store T, pass const T*
+// - StoreCopyPassByPtr<T> :Store T, pass T* (of copy!)
+// Or create your own class with PassAsParameter() method, optional
+// clean-up in destructor, and with associated IsParameterStorageClass<>.
+template <typename T>
+struct ParameterStorage
+ : std::conditional<IsParameterStorageClass<T>::value, T,
+ typename NonParameterStorageClass<T>::Type> {
+ using Type = typename ParameterStorage::conditional::type;
+};
+
+template <class T>
+static auto HasSetDeadlineTest(int)
+ -> SFINAE1True<decltype(std::declval<T>().SetDeadline(
+ std::declval<mozilla::TimeStamp>()))>;
+
+template <class T>
+static auto HasSetDeadlineTest(long) -> std::false_type;
+
+template <class T>
+struct HasSetDeadline : decltype(HasSetDeadlineTest<T>(0)) {};
+
+template <class T>
+std::enable_if_t<::detail::HasSetDeadline<T>::value> SetDeadlineImpl(
+ T* aObj, mozilla::TimeStamp aTimeStamp) {
+ aObj->SetDeadline(aTimeStamp);
+}
+
+template <class T>
+std::enable_if_t<!::detail::HasSetDeadline<T>::value> SetDeadlineImpl(
+ T* aObj, mozilla::TimeStamp aTimeStamp) {}
+} /* namespace detail */
+
+namespace mozilla {
+namespace detail {
+
+// struct used to store arguments and later apply them to a method.
+template <typename... Ts>
+struct RunnableMethodArguments final {
+ std::tuple<typename ::detail::ParameterStorage<Ts>::Type...> mArguments;
+ template <typename... As>
+ explicit RunnableMethodArguments(As&&... aArguments)
+ : mArguments(std::forward<As>(aArguments)...) {}
+ template <class C, typename M>
+ decltype(auto) apply(C* o, M m) {
+ return std::apply(
+ [&o, m](auto&&... args) {
+ return ((*o).*m)(args.PassAsParameter()...);
+ },
+ mArguments);
+ }
+};
+
+template <typename PtrType, typename Method, bool Owning, RunnableKind Kind,
+ typename... Storages>
+class RunnableMethodImpl final
+ : public ::nsRunnableMethodTraits<PtrType, Method, Owning,
+ Kind>::base_type {
+ typedef typename ::nsRunnableMethodTraits<PtrType, Method, Owning, Kind>
+ Traits;
+
+ typedef typename Traits::class_type ClassType;
+ typedef typename Traits::base_type BaseType;
+ ::nsRunnableMethodReceiver<ClassType, Owning> mReceiver;
+ Method mMethod;
+ RunnableMethodArguments<Storages...> mArgs;
+ using BaseType::CancelTimer;
+ using BaseType::GetTimer;
+
+ private:
+ virtual ~RunnableMethodImpl() { Revoke(); };
+ static void TimedOut(nsITimer* aTimer, void* aClosure) {
+ static_assert(IsIdle(Kind), "Don't use me!");
+ RefPtr<CancelableIdleRunnable> r =
+ static_cast<CancelableIdleRunnable*>(aClosure);
+ r->SetDeadline(TimeStamp());
+ r->Run();
+ r->Cancel();
+ }
+
+ public:
+ template <typename ForwardedPtrType, typename... Args>
+ explicit RunnableMethodImpl(const char* aName, ForwardedPtrType&& aObj,
+ Method aMethod, Args&&... aArgs)
+ : BaseType(aName),
+ mReceiver(std::forward<ForwardedPtrType>(aObj)),
+ mMethod(aMethod),
+ mArgs(std::forward<Args>(aArgs)...) {
+ static_assert(sizeof...(Storages) == sizeof...(Args),
+ "Storages and Args should have equal sizes");
+ }
+
+ NS_IMETHOD Run() {
+ CancelTimer();
+
+ if (MOZ_LIKELY(mReceiver.Get())) {
+ mArgs.apply(mReceiver.Get(), mMethod);
+ }
+
+ return NS_OK;
+ }
+
+ nsresult Cancel() {
+ static_assert(Kind >= RunnableKind::Cancelable, "Don't use me!");
+ Revoke();
+ return NS_OK;
+ }
+
+ void Revoke() {
+ CancelTimer();
+ mReceiver.Revoke();
+ }
+
+ void SetDeadline(TimeStamp aDeadline) {
+ if (MOZ_LIKELY(mReceiver.Get())) {
+ ::detail::SetDeadlineImpl(mReceiver.Get(), aDeadline);
+ }
+ }
+
+ void SetTimer(uint32_t aDelay, nsIEventTarget* aTarget) {
+ MOZ_ASSERT(aTarget);
+
+ if (nsCOMPtr<nsITimer> timer = GetTimer()) {
+ timer->Cancel();
+ timer->SetTarget(aTarget);
+ timer->InitWithNamedFuncCallback(TimedOut, this, aDelay,
+ nsITimer::TYPE_ONE_SHOT,
+ "detail::RunnableMethodImpl::SetTimer");
+ }
+ }
+};
+
+// Type aliases for NewRunnableMethod.
+template <typename PtrType, typename Method>
+using OwningRunnableMethod =
+ typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+ true, RunnableKind::Standard>::base_type;
+template <typename PtrType, typename Method, typename... Storages>
+using OwningRunnableMethodImpl =
+ RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, true,
+ RunnableKind::Standard, Storages...>;
+
+// Type aliases for NewCancelableRunnableMethod.
+template <typename PtrType, typename Method>
+using CancelableRunnableMethod =
+ typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+ true,
+ RunnableKind::Cancelable>::base_type;
+template <typename PtrType, typename Method, typename... Storages>
+using CancelableRunnableMethodImpl =
+ RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, true,
+ RunnableKind::Cancelable, Storages...>;
+
+// Type aliases for NewIdleRunnableMethod.
+template <typename PtrType, typename Method>
+using IdleRunnableMethod =
+ typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+ true, RunnableKind::Idle>::base_type;
+template <typename PtrType, typename Method, typename... Storages>
+using IdleRunnableMethodImpl =
+ RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, true,
+ RunnableKind::Idle, Storages...>;
+
+// Type aliases for NewIdleRunnableMethodWithTimer.
+template <typename PtrType, typename Method>
+using IdleRunnableMethodWithTimer =
+ typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+ true,
+ RunnableKind::IdleWithTimer>::base_type;
+template <typename PtrType, typename Method, typename... Storages>
+using IdleRunnableMethodWithTimerImpl =
+ RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, true,
+ RunnableKind::IdleWithTimer, Storages...>;
+
+// Type aliases for NewNonOwningRunnableMethod.
+template <typename PtrType, typename Method>
+using NonOwningRunnableMethod =
+ typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+ false, RunnableKind::Standard>::base_type;
+template <typename PtrType, typename Method, typename... Storages>
+using NonOwningRunnableMethodImpl =
+ RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, false,
+ RunnableKind::Standard, Storages...>;
+
+// Type aliases for NonOwningCancelableRunnableMethod
+template <typename PtrType, typename Method>
+using NonOwningCancelableRunnableMethod =
+ typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+ false,
+ RunnableKind::Cancelable>::base_type;
+template <typename PtrType, typename Method, typename... Storages>
+using NonOwningCancelableRunnableMethodImpl =
+ RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, false,
+ RunnableKind::Cancelable, Storages...>;
+
+// Type aliases for NonOwningIdleRunnableMethod
+template <typename PtrType, typename Method>
+using NonOwningIdleRunnableMethod =
+ typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+ false, RunnableKind::Idle>::base_type;
+template <typename PtrType, typename Method, typename... Storages>
+using NonOwningIdleRunnableMethodImpl =
+ RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, false,
+ RunnableKind::Idle, Storages...>;
+
+// Type aliases for NewIdleRunnableMethodWithTimer.
+template <typename PtrType, typename Method>
+using NonOwningIdleRunnableMethodWithTimer =
+ typename ::nsRunnableMethodTraits<std::remove_reference_t<PtrType>, Method,
+ false,
+ RunnableKind::IdleWithTimer>::base_type;
+template <typename PtrType, typename Method, typename... Storages>
+using NonOwningIdleRunnableMethodWithTimerImpl =
+ RunnableMethodImpl<std::remove_reference_t<PtrType>, Method, false,
+ RunnableKind::IdleWithTimer, Storages...>;
+
+} // namespace detail
+
+// NewRunnableMethod and friends
+//
+// Very often in Gecko, you'll find yourself in a situation where you want
+// to invoke a method (with or without arguments) asynchronously. You
+// could write a small helper class inheriting from nsRunnable to handle
+// all these details, or you could let NewRunnableMethod take care of all
+// those details for you.
+//
+// The simplest use of NewRunnableMethod looks like:
+//
+// nsCOMPtr<nsIRunnable> event =
+// mozilla::NewRunnableMethod("description", myObject,
+// &MyClass::HandleEvent);
+// NS_DispatchToCurrentThread(event);
+//
+// Statically enforced constraints:
+// - myObject must be of (or implicitly convertible to) type MyClass
+// - MyClass must define AddRef and Release methods
+//
+// The "description" string should specify a human-readable name for the
+// runnable; the provided string is used by various introspection tools
+// in the browser.
+//
+// The created runnable will take a strong reference to `myObject`. For
+// non-refcounted objects, or refcounted objects with unusual refcounting
+// requirements, and if and only if you are 110% certain that `myObject`
+// will live long enough, you can use NewNonOwningRunnableMethod instead,
+// which will, as its name implies, take a non-owning reference. If you
+// find yourself having to use this function, you should accompany your use
+// with a proof comment describing why the runnable will not lead to
+// use-after-frees.
+//
+// (If you find yourself writing contorted code to Release() an object
+// asynchronously on a different thread, you should use the
+// NS_ProxyRelease function.)
+//
+// Invoking a method with arguments takes a little more care. The
+// natural extension of the above:
+//
+// nsCOMPtr<nsIRunnable> event =
+// mozilla::NewRunnableMethod("description", myObject,
+// &MyClass::HandleEvent,
+// arg1, arg2, ...);
+//
+// can lead to security hazards (e.g. passing in raw pointers to refcounted
+// objects and storing those raw pointers in the runnable). We therefore
+// require you to specify the storage types used by the runnable, just as
+// you would if you were writing out the class by hand:
+//
+// nsCOMPtr<nsIRunnable> event =
+// mozilla::NewRunnableMethod<RefPtr<T>, nsTArray<U>>
+// ("description", myObject, &MyClass::HandleEvent, arg1, arg2);
+//
+// Please note that you do not have to pass the same argument type as you
+// specify in the template arguments. For example, if you want to transfer
+// ownership to a runnable, you can write:
+//
+// RefPtr<T> ptr = ...;
+// nsTArray<U> array = ...;
+// nsCOMPtr<nsIRunnable> event =
+// mozilla::NewRunnableMethod<RefPtr<T>, nsTArray<U>>
+// ("description", myObject, &MyClass::DoSomething,
+// std::move(ptr), std::move(array));
+//
+// and there will be no extra AddRef/Release traffic, or copying of the array.
+//
+// Each type that you specify as a template argument to NewRunnableMethod
+// comes with its own style of storage in the runnable and its own style
+// of argument passing to the invoked method. See the comment for
+// ParameterStorage above for more details.
+//
+// If you need to customize the storage type and/or argument passing type,
+// you can write your own class to use as a template argument to
+// NewRunnableMethod. If you find yourself having to do that frequently,
+// please file a bug in Core::XPCOM about adding the custom type to the
+// core code in this file, and/or for custom rules for ParameterStorage
+// to select that strategy.
+//
+// For places that require you to use cancelable runnables, such as
+// workers, there's also NewCancelableRunnableMethod and its non-owning
+// counterpart. The runnables returned by these methods additionally
+// implement nsICancelableRunnable.
+//
+// Finally, all of the functions discussed above have additional overloads
+// that do not take a `const char*` as their first parameter; you may see
+// these in older code. The `const char*` overload is preferred and
+// should be used in new code exclusively.
+
+template <typename PtrType, typename Method>
+already_AddRefed<detail::OwningRunnableMethod<PtrType, Method>>
+NewRunnableMethod(const char* aName, PtrType&& aPtr, Method aMethod) {
+ return do_AddRef(new detail::OwningRunnableMethodImpl<PtrType, Method>(
+ aName, std::forward<PtrType>(aPtr), aMethod));
+}
+
+template <typename PtrType, typename Method>
+already_AddRefed<detail::CancelableRunnableMethod<PtrType, Method>>
+NewCancelableRunnableMethod(const char* aName, PtrType&& aPtr, Method aMethod) {
+ return do_AddRef(new detail::CancelableRunnableMethodImpl<PtrType, Method>(
+ aName, std::forward<PtrType>(aPtr), aMethod));
+}
+
+template <typename PtrType, typename Method>
+already_AddRefed<detail::IdleRunnableMethod<PtrType, Method>>
+NewIdleRunnableMethod(const char* aName, PtrType&& aPtr, Method aMethod) {
+ return do_AddRef(new detail::IdleRunnableMethodImpl<PtrType, Method>(
+ aName, std::forward<PtrType>(aPtr), aMethod));
+}
+
+template <typename PtrType, typename Method>
+already_AddRefed<detail::IdleRunnableMethodWithTimer<PtrType, Method>>
+NewIdleRunnableMethodWithTimer(const char* aName, PtrType&& aPtr,
+ Method aMethod) {
+ return do_AddRef(new detail::IdleRunnableMethodWithTimerImpl<PtrType, Method>(
+ aName, std::forward<PtrType>(aPtr), aMethod));
+}
+
+template <typename PtrType, typename Method>
+already_AddRefed<detail::NonOwningRunnableMethod<PtrType, Method>>
+NewNonOwningRunnableMethod(const char* aName, PtrType&& aPtr, Method aMethod) {
+ return do_AddRef(new detail::NonOwningRunnableMethodImpl<PtrType, Method>(
+ aName, std::forward<PtrType>(aPtr), aMethod));
+}
+
+template <typename PtrType, typename Method>
+already_AddRefed<detail::NonOwningCancelableRunnableMethod<PtrType, Method>>
+NewNonOwningCancelableRunnableMethod(const char* aName, PtrType&& aPtr,
+ Method aMethod) {
+ return do_AddRef(
+ new detail::NonOwningCancelableRunnableMethodImpl<PtrType, Method>(
+ aName, std::forward<PtrType>(aPtr), aMethod));
+}
+
+template <typename PtrType, typename Method>
+already_AddRefed<detail::NonOwningIdleRunnableMethod<PtrType, Method>>
+NewNonOwningIdleRunnableMethod(const char* aName, PtrType&& aPtr,
+ Method aMethod) {
+ return do_AddRef(new detail::NonOwningIdleRunnableMethodImpl<PtrType, Method>(
+ aName, std::forward<PtrType>(aPtr), aMethod));
+}
+
+template <typename PtrType, typename Method>
+already_AddRefed<detail::NonOwningIdleRunnableMethodWithTimer<PtrType, Method>>
+NewNonOwningIdleRunnableMethodWithTimer(const char* aName, PtrType&& aPtr,
+ Method aMethod) {
+ return do_AddRef(
+ new detail::NonOwningIdleRunnableMethodWithTimerImpl<PtrType, Method>(
+ aName, std::forward<PtrType>(aPtr), aMethod));
+}
+
+// Similar to NewRunnableMethod. Call like so:
+// nsCOMPtr<nsIRunnable> event =
+// NewRunnableMethod<Types,...>(myObject, &MyClass::HandleEvent, myArg1,...);
+// 'Types' are the stored type for each argument, see ParameterStorage for
+// details.
+template <typename... Storages, typename PtrType, typename Method,
+ typename... Args>
+already_AddRefed<detail::OwningRunnableMethod<PtrType, Method>>
+NewRunnableMethod(const char* aName, PtrType&& aPtr, Method aMethod,
+ Args&&... aArgs) {
+ static_assert(sizeof...(Storages) == sizeof...(Args),
+ "<Storages...> size should be equal to number of arguments");
+ return do_AddRef(
+ new detail::OwningRunnableMethodImpl<PtrType, Method, Storages...>(
+ aName, std::forward<PtrType>(aPtr), aMethod,
+ std::forward<Args>(aArgs)...));
+}
+
+template <typename... Storages, typename PtrType, typename Method,
+ typename... Args>
+already_AddRefed<detail::NonOwningRunnableMethod<PtrType, Method>>
+NewNonOwningRunnableMethod(const char* aName, PtrType&& aPtr, Method aMethod,
+ Args&&... aArgs) {
+ static_assert(sizeof...(Storages) == sizeof...(Args),
+ "<Storages...> size should be equal to number of arguments");
+ return do_AddRef(
+ new detail::NonOwningRunnableMethodImpl<PtrType, Method, Storages...>(
+ aName, std::forward<PtrType>(aPtr), aMethod,
+ std::forward<Args>(aArgs)...));
+}
+
+template <typename... Storages, typename PtrType, typename Method,
+ typename... Args>
+already_AddRefed<detail::CancelableRunnableMethod<PtrType, Method>>
+NewCancelableRunnableMethod(const char* aName, PtrType&& aPtr, Method aMethod,
+ Args&&... aArgs) {
+ static_assert(sizeof...(Storages) == sizeof...(Args),
+ "<Storages...> size should be equal to number of arguments");
+ return do_AddRef(
+ new detail::CancelableRunnableMethodImpl<PtrType, Method, Storages...>(
+ aName, std::forward<PtrType>(aPtr), aMethod,
+ std::forward<Args>(aArgs)...));
+}
+
+template <typename... Storages, typename PtrType, typename Method,
+ typename... Args>
+already_AddRefed<detail::NonOwningCancelableRunnableMethod<PtrType, Method>>
+NewNonOwningCancelableRunnableMethod(const char* aName, PtrType&& aPtr,
+ Method aMethod, Args&&... aArgs) {
+ static_assert(sizeof...(Storages) == sizeof...(Args),
+ "<Storages...> size should be equal to number of arguments");
+ return do_AddRef(
+ new detail::NonOwningCancelableRunnableMethodImpl<PtrType, Method,
+ Storages...>(
+ aName, std::forward<PtrType>(aPtr), aMethod,
+ std::forward<Args>(aArgs)...));
+}
+
+template <typename... Storages, typename PtrType, typename Method,
+ typename... Args>
+already_AddRefed<detail::IdleRunnableMethod<PtrType, Method>>
+NewIdleRunnableMethod(const char* aName, PtrType&& aPtr, Method aMethod,
+ Args&&... aArgs) {
+ static_assert(sizeof...(Storages) == sizeof...(Args),
+ "<Storages...> size should be equal to number of arguments");
+ return do_AddRef(
+ new detail::IdleRunnableMethodImpl<PtrType, Method, Storages...>(
+ aName, std::forward<PtrType>(aPtr), aMethod,
+ std::forward<Args>(aArgs)...));
+}
+
+template <typename... Storages, typename PtrType, typename Method,
+ typename... Args>
+already_AddRefed<detail::NonOwningIdleRunnableMethod<PtrType, Method>>
+NewNonOwningIdleRunnableMethod(const char* aName, PtrType&& aPtr,
+ Method aMethod, Args&&... aArgs) {
+ static_assert(sizeof...(Storages) == sizeof...(Args),
+ "<Storages...> size should be equal to number of arguments");
+ return do_AddRef(
+ new detail::NonOwningIdleRunnableMethodImpl<PtrType, Method, Storages...>(
+ aName, std::forward<PtrType>(aPtr), aMethod,
+ std::forward<Args>(aArgs)...));
+}
+
+} // namespace mozilla
+
+#endif // XPCOM_GLUE_AVOID_NSPR
+
+// This class is designed to be used when you have an event class E that has a
+// pointer back to resource class R. If R goes away while E is still pending,
+// then it is important to "revoke" E so that it does not try use R after R has
+// been destroyed. nsRevocableEventPtr makes it easy for R to manage such
+// situations:
+//
+// class R;
+//
+// class E : public mozilla::Runnable {
+// public:
+// void Revoke() {
+// mResource = nullptr;
+// }
+// private:
+// R *mResource;
+// };
+//
+// class R {
+// public:
+// void EventHandled() {
+// mEvent.Forget();
+// }
+// private:
+// nsRevocableEventPtr<E> mEvent;
+// };
+//
+// void R::PostEvent() {
+// // Make sure any pending event is revoked.
+// mEvent->Revoke();
+//
+// nsCOMPtr<nsIRunnable> event = new E();
+// if (NS_SUCCEEDED(NS_DispatchToCurrentThread(event))) {
+// // Keep pointer to event so we can revoke it.
+// mEvent = event;
+// }
+// }
+//
+// NS_IMETHODIMP E::Run() {
+// if (!mResource)
+// return NS_OK;
+// ...
+// mResource->EventHandled();
+// return NS_OK;
+// }
+//
+template <class T>
+class nsRevocableEventPtr {
+ public:
+ nsRevocableEventPtr() : mEvent(nullptr) {}
+ ~nsRevocableEventPtr() { Revoke(); }
+
+ const nsRevocableEventPtr& operator=(RefPtr<T>&& aEvent) {
+ if (mEvent != aEvent) {
+ Revoke();
+ mEvent = std::move(aEvent);
+ }
+ return *this;
+ }
+
+ void Revoke() {
+ if (mEvent) {
+ mEvent->Revoke();
+ mEvent = nullptr;
+ }
+ }
+
+ void Forget() { mEvent = nullptr; }
+ bool IsPending() { return mEvent != nullptr; }
+ T* get() { return mEvent; }
+
+ private:
+ // Not implemented
+ nsRevocableEventPtr(const nsRevocableEventPtr&);
+ nsRevocableEventPtr& operator=(const nsRevocableEventPtr&);
+
+ RefPtr<T> mEvent;
+};
+
+template <class T>
+inline already_AddRefed<T> do_AddRef(nsRevocableEventPtr<T>& aObj) {
+ return do_AddRef(aObj.get());
+}
+
+/**
+ * A simple helper to suffix thread pool name
+ * with incremental numbers.
+ */
+class nsThreadPoolNaming {
+ public:
+ nsThreadPoolNaming() = default;
+
+ /**
+ * Returns a thread name as "<aPoolName> #<n>" and increments the counter.
+ */
+ nsCString GetNextThreadName(const nsACString& aPoolName);
+
+ template <size_t LEN>
+ nsCString GetNextThreadName(const char (&aPoolName)[LEN]) {
+ return GetNextThreadName(nsDependentCString(aPoolName, LEN - 1));
+ }
+
+ private:
+ mozilla::Atomic<uint32_t> mCounter{0};
+
+ nsThreadPoolNaming(const nsThreadPoolNaming&) = delete;
+ void operator=(const nsThreadPoolNaming&) = delete;
+};
+
+/**
+ * Thread priority in most operating systems affect scheduling, not IO. This
+ * helper is used to set the current thread to low IO priority for the lifetime
+ * of the created object. You can only use this low priority IO setting within
+ * the context of the current thread.
+ */
+class MOZ_STACK_CLASS nsAutoLowPriorityIO {
+ public:
+ nsAutoLowPriorityIO();
+ ~nsAutoLowPriorityIO();
+
+ private:
+ bool lowIOPrioritySet;
+#if defined(XP_MACOSX)
+ int oldPriority;
+#endif
+};
+
+void NS_SetMainThread();
+
+// Used only on cooperatively scheduled "main" threads. Causes the thread to be
+// considered a main thread and also causes GetCurrentVirtualThread to return
+// aVirtualThread.
+void NS_SetMainThread(PRThread* aVirtualThread);
+
+// Used only on cooperatively scheduled "main" threads. Causes the thread to no
+// longer be considered a main thread. Also causes GetCurrentVirtualThread() to
+// return a unique value.
+void NS_UnsetMainThread();
+
+/**
+ * Return the expiration time of the next timer to run on the current
+ * thread. If that expiration time is greater than aDefault, then
+ * return aDefault. aSearchBound specifies a maximum number of timers
+ * to examine to find a timer on the current thread. If no timer that
+ * will run on the current thread is found after examining
+ * aSearchBound timers, return the highest seen expiration time as a
+ * best effort guess.
+ *
+ * Timers with either the type nsITimer::TYPE_ONE_SHOT_LOW_PRIORITY or
+ * nsITIMER::TYPE_REPEATING_SLACK_LOW_PRIORITY will be skipped when
+ * searching for the next expiration time. This enables timers to
+ * have lower priority than callbacks dispatched from
+ * nsIThread::IdleDispatch.
+ */
+extern mozilla::TimeStamp NS_GetTimerDeadlineHintOnCurrentThread(
+ mozilla::TimeStamp aDefault, uint32_t aSearchBound);
+
+/**
+ * Dispatches the given event to a background thread. The primary benefit of
+ * this API is that you do not have to manage the lifetime of your own thread
+ * for running your own events; the thread manager will take care of the
+ * background thread's lifetime. Not having to manage your own thread also
+ * means less resource usage, as the underlying implementation here can manage
+ * spinning up and shutting down threads appropriately.
+ *
+ * NOTE: there is no guarantee that events dispatched via these APIs are run
+ * serially, in dispatch order; several dispatched events may run in parallel.
+ * If you depend on serial execution of dispatched events, you should use
+ * NS_CreateBackgroundTaskQueue instead, and dispatch events to the returned
+ * event target.
+ */
+extern nsresult NS_DispatchBackgroundTask(
+ already_AddRefed<nsIRunnable> aEvent,
+ uint32_t aDispatchFlags = NS_DISPATCH_NORMAL);
+extern "C" nsresult NS_DispatchBackgroundTask(
+ nsIRunnable* aEvent, uint32_t aDispatchFlags = NS_DISPATCH_NORMAL);
+
+/**
+ * Obtain a new serial event target that dispatches runnables to a background
+ * thread. In many cases, this is a straight replacement for creating your
+ * own, private thread, and is generally preferred to creating your own,
+ * private thread.
+ */
+extern "C" nsresult NS_CreateBackgroundTaskQueue(
+ const char* aName, nsISerialEventTarget** aTarget);
+
+/**
+ * Dispatch the given runnable to the given event target, spinning the current
+ * thread's event loop until the runnable has finished executing.
+ *
+ * This is roughly equivalent to the previously-supported `NS_DISPATCH_SYNC`
+ * flag.
+ */
+extern nsresult NS_DispatchAndSpinEventLoopUntilComplete(
+ const nsACString& aVeryGoodReasonToDoThis, nsIEventTarget* aEventTarget,
+ already_AddRefed<nsIRunnable> aEvent);
+
+// Predeclaration for logging function below
+namespace IPC {
+class Message;
+class MessageReader;
+class MessageWriter;
+} // namespace IPC
+
+class nsTimerImpl;
+
+namespace mozilla {
+
+// RAII class that will set the TLS entry to return the currently running
+// nsISerialEventTarget.
+// It should be used from inner event loop implementation.
+class SerialEventTargetGuard {
+ public:
+ explicit SerialEventTargetGuard(nsISerialEventTarget* aThread)
+ : mLastCurrentThread(sCurrentThreadTLS.get()) {
+ Set(aThread);
+ }
+
+ ~SerialEventTargetGuard() { sCurrentThreadTLS.set(mLastCurrentThread); }
+
+ static void InitTLS();
+ static nsISerialEventTarget* GetCurrentSerialEventTarget() {
+ return sCurrentThreadTLS.get();
+ }
+
+ protected:
+ friend class ::MessageLoop;
+ static void Set(nsISerialEventTarget* aThread) {
+ MOZ_ASSERT(aThread->IsOnCurrentThread());
+ sCurrentThreadTLS.set(aThread);
+ }
+
+ private:
+ static MOZ_THREAD_LOCAL(nsISerialEventTarget*) sCurrentThreadTLS;
+ nsISerialEventTarget* mLastCurrentThread;
+};
+
+// Get the serial event target corresponding to the currently executing task
+// queue or thread. This method will assert if called on a thread pool without
+// an active task queue.
+//
+// This function should generally be preferred over NS_GetCurrentThread since it
+// will return a more useful answer when called from a task queue running on a
+// thread pool or on a non-xpcom thread which accepts runnable dispatches.
+//
+// NOTE: The returned nsISerialEventTarget may not accept runnable dispatches
+// (e.g. if it corresponds to a non-xpcom thread), however it may still be used
+// to check if you're on the given thread/queue using IsOnCurrentThread().
+
+nsISerialEventTarget* GetCurrentSerialEventTarget();
+
+// Get a weak reference to a serial event target which can be used to dispatch
+// runnables to the main thread.
+//
+// NOTE: While this is currently a weak pointer to the nsIThread* returned from
+// NS_GetMainThread(), this may change in the future.
+
+nsISerialEventTarget* GetMainThreadSerialEventTarget();
+
+// Returns the number of CPUs, like PR_GetNumberOfProcessors, except
+// that it can return a cached value on platforms where sandboxing
+// would prevent reading the current value (currently Linux). CPU
+// hotplugging is uncommon, so this is unlikely to make a difference
+// in practice.
+size_t GetNumberOfProcessors();
+
+/**
+ * A helper class to log tasks dispatch and run with "MOZ_LOG=events:1". The
+ * output is more machine readable and creates a link between dispatch and run.
+ *
+ * Usage example for the concrete template type nsIRunnable.
+ * To log a dispatch, which means putting an event to a queue:
+ * LogRunnable::LogDispatch(event);
+ * theQueue.putEvent(event);
+ *
+ * To log execution (running) of the event:
+ * nsCOMPtr<nsIRunnable> event = theQueue.popEvent();
+ * {
+ * LogRunnable::Run log(event);
+ * event->Run();
+ * event = null; // to include the destructor code in the span
+ * }
+ *
+ * The class is a template so that we can support various specific super-types
+ * of tasks in the future. We can't use void* because it may cast differently
+ * and tracking the pointer in logs would then be impossible.
+ */
+template <typename T>
+class LogTaskBase {
+ public:
+ LogTaskBase() = delete;
+
+ // Adds a simple log about dispatch of this runnable.
+ static void LogDispatch(T* aEvent);
+ // The `aContext` pointer adds another uniqe identifier, nothing more
+ static void LogDispatch(T* aEvent, void* aContext);
+
+ // Logs dispatch of the message and along that also the PID of the target
+ // proccess, purposed for uniquely identifying IPC messages.
+ static void LogDispatchWithPid(T* aEvent, int32_t aPid);
+
+ // This is designed to surround a call to `Run()` or any code representing
+ // execution of the task body.
+ // The constructor adds a simple log about start of the runnable execution and
+ // the destructor adds a log about ending the execution.
+ class MOZ_RAII Run {
+ public:
+ Run() = delete;
+ explicit Run(T* aEvent, bool aWillRunAgain = false);
+ explicit Run(T* aEvent, void* aContext, bool aWillRunAgain = false);
+ ~Run();
+
+ // When this is called, the log in this RAII dtor will only say
+ // "interrupted" expecting that the event will run again.
+ void WillRunAgain() { mWillRunAgain = true; }
+
+ private:
+ bool mWillRunAgain = false;
+ };
+};
+
+class MicroTaskRunnable;
+class Task; // TaskController
+class PresShell;
+namespace dom {
+class FrameRequestCallback;
+} // namespace dom
+
+// Specialized methods must be explicitly predeclared.
+template <>
+LogTaskBase<nsIRunnable>::Run::Run(nsIRunnable* aEvent, bool aWillRunAgain);
+template <>
+LogTaskBase<Task>::Run::Run(Task* aTask, bool aWillRunAgain);
+template <>
+void LogTaskBase<IPC::Message>::LogDispatchWithPid(IPC::Message* aEvent,
+ int32_t aPid);
+template <>
+LogTaskBase<IPC::Message>::Run::Run(IPC::Message* aMessage, bool aWillRunAgain);
+template <>
+LogTaskBase<nsTimerImpl>::Run::Run(nsTimerImpl* aEvent, bool aWillRunAgain);
+
+typedef LogTaskBase<nsIRunnable> LogRunnable;
+typedef LogTaskBase<MicroTaskRunnable> LogMicroTaskRunnable;
+typedef LogTaskBase<IPC::Message> LogIPCMessage;
+typedef LogTaskBase<nsTimerImpl> LogTimerEvent;
+typedef LogTaskBase<Task> LogTask;
+typedef LogTaskBase<PresShell> LogPresShellObserver;
+typedef LogTaskBase<dom::FrameRequestCallback> LogFrameRequestCallback;
+// If you add new types don't forget to add:
+// `template class LogTaskBase<YourType>;` to nsThreadUtils.cpp
+
+} // namespace mozilla
+
+#endif // nsThreadUtils_h__