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/* -*- 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
#ifndef mozilla_dom_workers_workerrunnable_h__
#define mozilla_dom_workers_workerrunnable_h__
#include <cstdint>
#include <utility>
#include "MainThreadUtils.h"
#include "mozilla/Atomics.h"
#include "mozilla/RefPtr.h"
#include "mozilla/ThreadSafeWeakPtr.h"
#include "mozilla/dom/WorkerRef.h"
#include "mozilla/dom/WorkerStatus.h"
#include "nsCOMPtr.h"
#include "nsIRunnable.h"
#include "nsISupports.h"
#include "nsStringFwd.h"
#include "nsThreadUtils.h"
#include "nscore.h"
struct JSContext;
class nsIEventTarget;
class nsIGlobalObject;
namespace mozilla {
class ErrorResult;
namespace dom {
class Worker;
class WorkerParentRef;
class WorkerPrivate;
class WorkerRunnable : public nsIRunnable
#ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
,
public nsINamed
#endif
{
protected:
#ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
const char* mName = nullptr;
#endif
public:
NS_DECL_THREADSAFE_ISUPPORTS
#ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
NS_DECL_NSINAMED
#endif
virtual nsresult Cancel() = 0;
// The return value is true if and only if both PreDispatch and
// DispatchInternal return true.
virtual bool Dispatch(WorkerPrivate* aWorkerPrivate);
// True if this runnable is handled by running JavaScript in some global that
// could possibly be a debuggee, and thus needs to be deferred when the target
// is paused in the debugger, until the JavaScript invocation in progress has
// run to completion. Examples are MessageEventRunnable and
// ReportErrorRunnable. These runnables are segregated into separate
// ThrottledEventQueues, which the debugger pauses.
//
// Note that debugger runnables do not fall in this category, since we don't
// support debugging the debugger server at the moment.
virtual bool IsDebuggeeRunnable() const { return false; }
// True if this runnable needs to be dispatched to
// WorkerPrivate::mControlEventTareget.
virtual bool IsControlRunnable() const { return false; }
// True if this runnable should be dispatched to the debugger queue,
// and false otherwise.
virtual bool IsDebuggerRunnable() const { return false; }
static WorkerRunnable* FromRunnable(nsIRunnable* aRunnable);
protected:
explicit WorkerRunnable(const char* aName = "WorkerRunnable")
#ifdef DEBUG
;
#else
# ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
: mName(aName)
# endif
{
}
#endif
// This class is reference counted.
virtual ~WorkerRunnable() = default;
// Calling Run() directly is not supported. Just call Dispatch() and
// WorkerRun() will be called on the correct thread automatically.
NS_DECL_NSIRUNNABLE
// By default asserts that Dispatch() is being called on the right thread
virtual bool PreDispatch(WorkerPrivate* aWorkerPrivate) = 0;
// By default asserts that Dispatch() is being called on the right thread
virtual void PostDispatch(WorkerPrivate* aWorkerPrivate,
bool aDispatchResult) = 0;
virtual bool DispatchInternal(WorkerPrivate* aWorkerPrivate) = 0;
// May be implemented by subclasses if desired if they need to do some sort of
// setup before we try to set up our JSContext and compartment for real.
// Typically the only thing that should go in here is creation of the worker's
// global.
//
// If false is returned, WorkerRun will not be called at all. PostRun will
// still be called, with false passed for aRunResult.
virtual bool PreRun(WorkerPrivate* aWorkerPrivate) = 0;
// Must be implemented by subclasses. Called on the target thread. The return
// value will be passed to PostRun(). The JSContext passed in here comes from
// an AutoJSAPI (or AutoEntryScript) that we set up on the stack.
//
// If the runnable is for parent thread, aCx is in the compartment of
// mWorkerPrivate's reflector (i.e. the worker object in the parent thread),
// unless that reflector is null, in which case it's in the compartment of the
// parent global (which is the compartment reflector would have been in), or
// in the null compartment if there is no parent global.
//
// For runnables on the worker thread, aCx is in whatever
// compartment GetCurrentWorkerThreadJSContext() was in when
// nsIRunnable::Run() got called. This is actually important for cases when a
// runnable spins a syncloop and wants everything that happens during the
// syncloop to happen in the compartment that runnable set up (which may, for
// example, be a debugger sandbox compartment!). If aCx wasn't in a
// compartment to start with, aCx will be in either the debugger global's
// compartment or the worker's global's compartment depending on whether
// IsDebuggerRunnable() is true.
//
// Immediately after WorkerRun returns, the caller will assert that either it
// returns false or there is no exception pending on aCx. Then it will report
// any pending exceptions on aCx.
virtual bool WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) = 0;
// By default asserts that Run() (and WorkerRun()) were called on the correct
// thread.
//
// The aCx passed here is the same one as was passed to WorkerRun and is
// still in the same compartment. PostRun implementations must NOT leave an
// exception on the JSContext and must not run script, because the incoming
// JSContext may be in the null compartment.
virtual void PostRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
bool aRunResult) = 0;
};
class WorkerParentThreadRunnable : public WorkerRunnable {
public:
NS_INLINE_DECL_REFCOUNTING_INHERITED(WorkerParentThreadRunnable,
WorkerRunnable)
virtual nsresult Cancel() override;
protected:
explicit WorkerParentThreadRunnable(
const char* aName = "WorkerParentThreadRunnable");
// This class is reference counted.
virtual ~WorkerParentThreadRunnable();
virtual bool PreDispatch(WorkerPrivate* aWorkerPrivate) override;
virtual void PostDispatch(WorkerPrivate* aWorkerPrivate,
bool aDispatchResult) override;
virtual bool PreRun(WorkerPrivate* aWorkerPrivate) override;
virtual bool WorkerRun(JSContext* aCx,
WorkerPrivate* aWorkerPrivate) override = 0;
virtual void PostRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
bool aRunResult) override;
virtual bool DispatchInternal(WorkerPrivate* aWorkerPrivate) final;
// Calling Run() directly is not supported. Just call Dispatch() and
// WorkerRun() will be called on the correct thread automatically.
NS_DECL_NSIRUNNABLE
private:
RefPtr<WorkerParentRef> mWorkerParentRef;
};
class WorkerParentControlRunnable : public WorkerParentThreadRunnable {
friend class WorkerPrivate;
protected:
explicit WorkerParentControlRunnable(
const char* aName = "WorkerParentControlRunnable");
virtual ~WorkerParentControlRunnable();
nsresult Cancel() override;
public:
NS_INLINE_DECL_REFCOUNTING_INHERITED(WorkerParentControlRunnable,
WorkerParentThreadRunnable)
private:
bool IsControlRunnable() const override { return true; }
// Should only be called by WorkerPrivate::DoRunLoop.
using WorkerParentThreadRunnable::Cancel;
};
class WorkerParentDebuggeeRunnable : public WorkerParentThreadRunnable {
protected:
explicit WorkerParentDebuggeeRunnable(
const char* aName = "WorkerParentDebuggeeRunnable")
: WorkerParentThreadRunnable(aName) {}
private:
// This override is deliberately private: it doesn't make sense to call it if
// we know statically that we are a WorkerDebuggeeRunnable.
bool IsDebuggeeRunnable() const override { return true; }
};
class WorkerThreadRunnable : public WorkerRunnable {
public:
NS_INLINE_DECL_REFCOUNTING_INHERITED(WorkerThreadRunnable, WorkerRunnable)
virtual nsresult Cancel() override;
protected:
explicit WorkerThreadRunnable(const char* aName = "WorkerThreadRunnable");
// This class is reference counted.
virtual ~WorkerThreadRunnable() = default;
nsIGlobalObject* DefaultGlobalObject(WorkerPrivate* aWorkerPrivate) const;
virtual bool PreDispatch(WorkerPrivate* aWorkerPrivate) override;
virtual void PostDispatch(WorkerPrivate* aWorkerPrivate,
bool aDispatchResult) override;
virtual bool PreRun(WorkerPrivate* aWorkerPrivate) override;
virtual bool WorkerRun(JSContext* aCx,
WorkerPrivate* aWorkerPrivate) override = 0;
virtual void PostRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
bool aRunResult) override;
virtual bool DispatchInternal(WorkerPrivate* aWorkerPrivate) override;
// Calling Run() directly is not supported. Just call Dispatch() and
// WorkerRun() will be called on the correct thread automatically.
NS_DECL_NSIRUNNABLE
// Whether or not Cancel() is currently being called from inside the Run()
// method. Avoids infinite recursion when a subclass calls Run() from inside
// Cancel(). Only checked and modified on the target thread.
bool mCallingCancelWithinRun;
};
// This runnable is used to send a message to a worker debugger.
class WorkerDebuggerRunnable : public WorkerThreadRunnable {
protected:
explicit WorkerDebuggerRunnable(const char* aName = "WorkerDebuggerRunnable")
: WorkerThreadRunnable(aName) {}
virtual ~WorkerDebuggerRunnable() = default;
private:
virtual bool IsDebuggerRunnable() const override { return true; }
bool PreDispatch(WorkerPrivate* aWorkerPrivate) final {
AssertIsOnMainThread();
return true;
}
virtual void PostDispatch(WorkerPrivate* aWorkerPrivate,
bool aDispatchResult) override;
};
// This runnable is used to send a message directly to a worker's sync loop.
class WorkerSyncRunnable : public WorkerThreadRunnable {
protected:
nsCOMPtr<nsIEventTarget> mSyncLoopTarget;
// Passing null for aSyncLoopTarget is allowed and will result in the behavior
// of a normal WorkerThreadRunnable.
explicit WorkerSyncRunnable(nsIEventTarget* aSyncLoopTarget,
const char* aName = "WorkerSyncRunnable");
explicit WorkerSyncRunnable(nsCOMPtr<nsIEventTarget>&& aSyncLoopTarget,
const char* aName = "WorkerSyncRunnable");
virtual ~WorkerSyncRunnable();
virtual bool DispatchInternal(WorkerPrivate* aWorkerPrivate) override;
};
// This runnable is identical to WorkerSyncRunnable except it is meant to be
// created on and dispatched from the main thread only. Its WorkerRun/PostRun
// will run on the worker thread.
class MainThreadWorkerSyncRunnable : public WorkerSyncRunnable {
protected:
// Passing null for aSyncLoopTarget is allowed and will result in the behavior
// of a normal WorkerThreadRunnable.
explicit MainThreadWorkerSyncRunnable(
nsIEventTarget* aSyncLoopTarget,
const char* aName = "MainThreadWorkerSyncRunnable")
: WorkerSyncRunnable(aSyncLoopTarget, aName) {
AssertIsOnMainThread();
}
explicit MainThreadWorkerSyncRunnable(
nsCOMPtr<nsIEventTarget>&& aSyncLoopTarget,
const char* aName = "MainThreadWorkerSyncRunnable")
: WorkerSyncRunnable(std::move(aSyncLoopTarget), aName) {
AssertIsOnMainThread();
}
virtual ~MainThreadWorkerSyncRunnable() = default;
private:
virtual bool PreDispatch(WorkerPrivate* aWorkerPrivate) override {
AssertIsOnMainThread();
return true;
}
virtual void PostDispatch(WorkerPrivate* aWorkerPrivate,
bool aDispatchResult) override;
};
// This runnable is processed as soon as it is received by the worker,
// potentially running before previously queued runnables and perhaps even with
// other JS code executing on the stack. These runnables must not alter the
// state of the JS runtime and should only twiddle state values.
class WorkerControlRunnable : public WorkerThreadRunnable {
friend class WorkerPrivate;
protected:
explicit WorkerControlRunnable(const char* aName = "WorkerControlRunnable");
virtual ~WorkerControlRunnable() = default;
nsresult Cancel() override;
public:
NS_INLINE_DECL_REFCOUNTING_INHERITED(WorkerControlRunnable,
WorkerThreadRunnable)
private:
bool IsControlRunnable() const override { return true; }
// Should only be called by WorkerPrivate::DoRunLoop.
using WorkerThreadRunnable::Cancel;
};
// A convenience class for WorkerThreadRunnables that are originated on the main
// thread.
class MainThreadWorkerRunnable : public WorkerThreadRunnable {
protected:
explicit MainThreadWorkerRunnable(
const char* aName = "MainThreadWorkerRunnable")
: WorkerThreadRunnable(aName) {
AssertIsOnMainThread();
}
virtual ~MainThreadWorkerRunnable() = default;
virtual bool PreDispatch(WorkerPrivate* aWorkerPrivate) override {
AssertIsOnMainThread();
return true;
}
virtual void PostDispatch(WorkerPrivate* aWorkerPrivate,
bool aDispatchResult) override {
AssertIsOnMainThread();
}
};
// A convenience class for WorkerControlRunnables that originate on the main
// thread.
class MainThreadWorkerControlRunnable : public WorkerControlRunnable {
protected:
explicit MainThreadWorkerControlRunnable(
const char* aName = "MainThreadWorkerControlRunnable")
: WorkerControlRunnable(aName) {}
virtual ~MainThreadWorkerControlRunnable() = default;
virtual bool PreDispatch(WorkerPrivate* aWorkerPrivate) override {
AssertIsOnMainThread();
return true;
}
virtual void PostDispatch(WorkerPrivate* aWorkerPrivate,
bool aDispatchResult) override {
AssertIsOnMainThread();
}
};
// A WorkerThreadRunnable that should be dispatched from the worker to itself
// for async tasks.
//
// Async tasks will almost always want to use this since
// a WorkerSameThreadRunnable keeps the Worker from being GCed.
class WorkerSameThreadRunnable : public WorkerThreadRunnable {
protected:
explicit WorkerSameThreadRunnable(
const char* aName = "WorkerSameThreadRunnable")
: WorkerThreadRunnable(aName) {}
virtual ~WorkerSameThreadRunnable() = default;
virtual bool PreDispatch(WorkerPrivate* aWorkerPrivate) override;
virtual void PostDispatch(WorkerPrivate* aWorkerPrivate,
bool aDispatchResult) override;
// We just delegate PostRun to WorkerThreadRunnable, since it does exactly
// what we want.
};
// Base class for the runnable objects, which makes a synchronous call to
// dispatch the tasks from the worker thread to the main thread.
//
// Note that the derived class must override MainThreadRun.
class WorkerMainThreadRunnable : public Runnable {
protected:
WorkerPrivate* mWorkerPrivate;
nsCOMPtr<nsISerialEventTarget> mSyncLoopTarget;
const nsCString mTelemetryKey;
explicit WorkerMainThreadRunnable(WorkerPrivate* aWorkerPrivate,
const nsACString& aTelemetryKey);
~WorkerMainThreadRunnable();
virtual bool MainThreadRun() = 0;
public:
// Dispatch the runnable to the main thread. If dispatch to main thread
// fails, or if the worker is in a state equal or greater of aFailStatus, an
// error will be reported on aRv. Normally you want to use 'Canceling' for
// aFailStatus, except if you want an infallible runnable. In this case, use
// 'Killing'.
// In that case the error MUST be propagated out to script.
void Dispatch(WorkerStatus aFailStatus, ErrorResult& aRv);
private:
NS_IMETHOD Run() override;
};
// This runnable is an helper class for dispatching something from a worker
// thread to the main-thread and back to the worker-thread. During this
// operation, this class will keep the worker alive.
// The purpose of RunBackOnWorkerThreadForCleanup() must be used, as the name
// says, only to release resources, no JS has to be executed, no timers, or
// other things. The reason of such limitations is that, in order to execute
// this method in any condition (also when the worker is shutting down), a
// Control Runnable is used, and, this could generate a reordering of existing
// runnables.
class WorkerProxyToMainThreadRunnable : public Runnable {
protected:
WorkerProxyToMainThreadRunnable();
virtual ~WorkerProxyToMainThreadRunnable();
// First this method is called on the main-thread.
virtual void RunOnMainThread(WorkerPrivate* aWorkerPrivate) = 0;
// After this second method is called on the worker-thread.
virtual void RunBackOnWorkerThreadForCleanup(
WorkerPrivate* aWorkerPrivate) = 0;
public:
bool Dispatch(WorkerPrivate* aWorkerPrivate);
virtual bool ForMessaging() const { return false; }
private:
NS_IMETHOD Run() override;
void PostDispatchOnMainThread();
void ReleaseWorker();
RefPtr<ThreadSafeWorkerRef> mWorkerRef;
};
// This runnable is used to stop a sync loop and it's meant to be used on the
// main-thread only.
class MainThreadStopSyncLoopRunnable : public WorkerSyncRunnable {
nsresult mResult;
public:
// Passing null for aSyncLoopTarget is not allowed.
MainThreadStopSyncLoopRunnable(nsCOMPtr<nsIEventTarget>&& aSyncLoopTarget,
nsresult aResult);
// By default StopSyncLoopRunnables cannot be canceled since they could leave
// a sync loop spinning forever.
nsresult Cancel() override;
protected:
virtual ~MainThreadStopSyncLoopRunnable() = default;
private:
bool PreDispatch(WorkerPrivate* aWorkerPrivate) final {
AssertIsOnMainThread();
return true;
}
virtual void PostDispatch(WorkerPrivate* aWorkerPrivate,
bool aDispatchResult) override;
virtual bool WorkerRun(JSContext* aCx,
WorkerPrivate* aWorkerPrivate) override;
bool DispatchInternal(WorkerPrivate* aWorkerPrivate) final;
};
// Runnables handled by content JavaScript (MessageEventRunnable, JavaScript
// error reports, and so on) must not be delivered while that content is in the
// midst of being debugged; the debuggee must be allowed to complete its current
// JavaScript invocation and return to its own event loop. Only then is it
// prepared for messages sent from the worker.
//
// Runnables that need to be deferred in this way should inherit from this
// class. They will be routed to mMainThreadDebuggeeEventTarget, which is paused
// while the window is suspended, as it is whenever the debugger spins its
// nested event loop. When the debugger leaves its nested event loop, it resumes
// the window, so that mMainThreadDebuggeeEventTarget will resume delivering
// runnables from the worker when control returns to the main event loop.
//
// When a page enters the bfcache, it freezes all its workers. Since a frozen
// worker processes only control runnables, it doesn't take any special
// consideration to prevent WorkerDebuggeeRunnables sent from child to parent
// workers from running; they'll never run anyway. But WorkerDebuggeeRunnables
// from a top-level frozen worker to its parent window must not be delivered
// either, even as the main thread event loop continues to spin. Thus, freezing
// a top-level worker also pauses mMainThreadDebuggeeEventTarget.
class WorkerDebuggeeRunnable : public WorkerThreadRunnable {
protected:
explicit WorkerDebuggeeRunnable(const char* aName = "WorkerDebuggeeRunnable")
: WorkerThreadRunnable(aName) {}
private:
// This override is deliberately private: it doesn't make sense to call it if
// we know statically that we are a WorkerDebuggeeRunnable.
bool IsDebuggeeRunnable() const override { return true; }
};
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_workers_workerrunnable_h__