[Exposed=(Window, Worker)]
@@ -27,19 +24,17 @@ The `TaskPriorityChangeEvent` Interface {#sec-task-priority-change-event}
event . {{TaskPriorityChangeEvent/previousPriority}}Returns the {{TaskPriority}} of the corresponding {{TaskSignal}} prior to - this `prioritychange` event. +
Returns the {{TaskPriority}} of the corresponding {{TaskSignal}} prior to this + `prioritychange` event.
The new {{TaskPriority}} can be read with `event.target.priority`.
dictionary TaskControllerInit {
@@ -54,22 +49,21 @@ The `TaskController` Interface {#sec-task-controller}
};
-Note: {{TaskController}}'s {{AbortController/signal}} getter, which is
-inherited from {{AbortController}}, returns a {{TaskSignal}} object.
+Note: {{TaskController}}'s {{AbortController/signal}} getter, which is inherited from
+{{AbortController}}, returns a {{TaskSignal}} object.
controller = new {{TaskController/TaskController()|TaskController}}( |init| )
Returns a new {{TaskController}} whose {{AbortController/signal}} is - set to a newly created {{TaskSignal}} with its {{TaskSignal/priority}} - initialized to |init|'s {{TaskControllerInit/priority}}. +
Returns a new {{TaskController}} whose {{AbortController/signal}} is set to a newly created + {{TaskSignal}} with its {{TaskSignal/priority}} initialized to |init|'s + {{TaskControllerInit/priority}}.
controller . {{TaskController/setPriority()|setPriority}}( |priority| )
Invoking this method will change the associated {{TaskSignal}}'s - [=TaskSignal/priority=], signal the priority change to any observers, and - cause `prioritychange` events to be dispatched. +
Invoking this method will change the associated {{TaskSignal}}'s [=TaskSignal/priority=], + signal the priority change to any observers, and cause `prioritychange` events to be dispatched.
setPriority(|priority|)
-method steps are to [=TaskSignal/signal priority change=] on [=this=]'s
-[=AbortController/signal=] given |priority|.
+The setPriority(|priority|) method steps are to
+[=TaskSignal/signal priority change=] on [=this=]'s [=AbortController/signal=] given |priority|.
-The `TaskSignal` Interface {#sec-task-signal}
----------------------
+## The `TaskSignal` Interface ## {#sec-task-signal}
dictionary TaskSignalAnyInit {
@@ -104,9 +96,9 @@ The `TaskSignal` Interface {#sec-task-signal}
};
-Note: {{TaskSignal}} inherits from {{AbortSignal}} and can be used in APIs that
-accept an {{AbortSignal}}. Additionally, {{Scheduler/postTask()}} accepts an
-{{AbortSignal}}, which can be useful if dynamic prioritization is not needed.
+Note: {{TaskSignal}} inherits from {{AbortSignal}} and can be used in APIs that accept an
+{{AbortSignal}}. Additionally, {{Scheduler/postTask()}} accepts an {{AbortSignal}}, which can be
+useful if dynamic prioritization is not needed.
TaskSignal . any(|signals|, |init|)
@@ -137,30 +129,32 @@ A {{TaskSignal}} object has associated dependent signalsdependent (a
-boolean), which is initially false.
+A {{TaskSignal}} object has an associated dependent (a boolean), which is
+initially false.
-onprioritychange attribute
-is an [=event handler IDL attribute=] for the `onprioritychange`
-[=event handler=], whose [=event handler event type=] is
-prioritychange.
+The onprioritychange attribute is an [=event
+handler IDL attribute=] for the `onprioritychange` [=event handler=], whose [=event handler event
+type=] is prioritychange.
-To add a priority change algorithm |algorithm| to a
-{{TaskSignal}} object |signal|, [=set/append=] |algorithm| to |signal|'s
-[=TaskSignal/priority change algorithms=].
+The static any(|signals|, |init|) method steps are to
+return the result of [=creating a dependent task signal=] from |signals| and |init|.
-any(|signals|, |init|) method steps are:
+ To create a dependent task signal from a [=list=] of {{AbortSignal}} objects |signals|
+ and a {{TaskSignalAnyInit}} |init|:
1. Let |resultSignal| be the result of creating a dependent signal from
|signals| using the {{TaskSignal}} interface and the [=current realm=].
@@ -180,8 +174,8 @@ if it is a [=TaskSignal/dependent=] signal with a null [=TaskSignal/source signa
diff --git a/spec/introduction.md b/spec/introduction.md
index 57fc991..a5a7fe1 100644
--- a/spec/introduction.md
+++ b/spec/introduction.md
@@ -1,5 +1,4 @@
-Introduction {#intro}
-=====================
+# Introduction # {#intro}
diff --git a/spec/patches.md b/spec/patches.md
index c855ba8..6b990b5 100644
--- a/spec/patches.md
+++ b/spec/patches.md
@@ -1,14 +1,11 @@
-Modifications to Other Standards {#sec-patches}
-=====================
+# Modifications to Other Standards # {#sec-patches}
-The HTML Standard {#sec-patches-html}
----------------------
+## The HTML Standard ## {#sec-patches-html}
### `WindowOrWorkerGlobalScope` ### {#sec-patches-html-windoworworkerglobalscope}
-Each object implementing the {{WindowOrWorkerGlobalScope}} mixin has a
-corresponding scheduler, which
-is initialized as a new {{Scheduler}}.
+Each object implementing the {{WindowOrWorkerGlobalScope}} mixin has a corresponding
+scheduler, which is initialized as a new {{Scheduler}}.
partial interface mixin WindowOrWorkerGlobalScope {
@@ -16,43 +13,38 @@ is initialized as a new {{Scheduler}}.
};
-The scheduler attribute's
-getter steps are to return [=this=]'s [=WindowOrWorkerGlobalScope/scheduler=].
-
+The scheduler attribute's getter steps are to
+return [=this=]'s [=WindowOrWorkerGlobalScope/scheduler=].
### Event loop: definitions ### {#sec-patches-html-event-loop-definitions}
-Replace: For each [=event loop=], every [=task source=] must be associated with
-a specific [=task queue=].
+Replace: For each [=event loop=], every [=task source=] must be associated with a specific [=task
+queue=].
-With: For each [=event loop=], every [=task source=] that is not a
-[=scheduler task source=] must be associated with a specific [=task queue=].
+With: For each [=event loop=], every [=task source=] that is not a [=scheduler task source=] must be
+associated with a specific [=task queue=].
### Event loop: processing model ### {#sec-patches-html-event-loop-processing}
Add the following steps to the event loop processing steps, before step 1:
- 1. Let |queues| be the [=set=] of the [=event loop=]'s [=task queues=] that
- contain at least one runnable task.
- 1. Let |schedulers| be the [=set=] of all {{Scheduler}} objects whose
- [=relevant agent's=] [=agent/event loop=] is this event loop and that
- [=have a runnable task=].
- 1. If |schedulers| and |queues| are both [=list/empty=], skip to the
- microtasks step below.
+ 1. Let |queues| be the [=set=] of the [=event loop=]'s [=task queues=] that contain at least one
+ [=task/runnable=] [=task=].
+ 1. Let |schedulers| be the [=set=] of all {{Scheduler}} objects whose [=relevant agent's=]
+ [=agent/event loop=] is this event loop and that [=have a runnable task=].
+ 1. If |schedulers| and |queues| are both [=list/empty=], skip to the microtasks step
+ below.
Modify step 1 to read:
- 1. Let |taskQueue| be one of the following, chosen in an
- [=implementation-defined=] manner:
- * If |queues| is not [=list/empty=], one of the [=task queues=] in |queues|,
- chosen in an [=implementation-defined=] manner.
- * If |schedulers| is not [=list/empty=], the result of
- [=selecting the task queue of the next scheduler task=] from one of the
- {{Scheduler}}s in |schedulers|, chosen in an [=implementation-defined=]
- manner.
-
-Issue: The |taskQueue| in this step will either be a [=set=] of [=tasks=] or a
-[=set=] of [=scheduler tasks=]. The steps that follow only [=set/remove=] an
-[=set/item=], so they are *roughly* compatible. Ideally, there would be a
-common task queue interface that supports a `pop()` method that would return a
-plain [=task=], but that would invlove a fair amount of refactoring.
+ 1. Let |taskQueue| be one of the following, chosen in an [=implementation-defined=] manner:
+ * If |queues| is not [=list/empty=], one of the [=task queues=] in |queues|, chosen in an
+ [=implementation-defined=] manner.
+ * If |schedulers| is not [=list/empty=], the result of [=selecting the task queue of the next
+ scheduler task=] from one of the {{Scheduler}}s in |schedulers|, chosen in an
+ [=implementation-defined=] manner.
+
+Issue: The |taskQueue| in this step will either be a [=set=] of [=tasks=] or a [=set=] of
+[=scheduler tasks=]. The steps that follow only [=set/remove=] an [=set/item=], so they are
+*roughly* compatible. Ideally, there would be a common task queue interface that supports a `pop()`
+method that would return a plain [=task=], but that would involve a fair amount of refactoring.
diff --git a/spec/privacy.md b/spec/privacy.md
index 7cada1e..0be3fee 100644
--- a/spec/privacy.md
+++ b/spec/privacy.md
@@ -1,5 +1,4 @@
-Privacy Considerations {#sec-privacy}
-=====================
+# Privacy Considerations # {#sec-privacy}
diff --git a/spec/scheduling-tasks.md b/spec/scheduling-tasks.md
index 922b311..7a7ec89 100644
--- a/spec/scheduling-tasks.md
+++ b/spec/scheduling-tasks.md
@@ -1,8 +1,6 @@
-Scheduling Tasks {#sec-scheduling-tasks}
-=====================
+# Scheduling Tasks # {#sec-scheduling-tasks}
-Task Priorities {#sec-task-priorities}
----------------------
+## Task Priorities ## {#sec-task-priorities}
This spec formalizes three priorities to support scheduling tasks:
@@ -14,24 +12,22 @@ This spec formalizes three priorities to support scheduling tasks:
};
-user-blocking is the highest priority,
-and is meant to be used for tasks that are blocking the user's ability to
-interact with the page, such as rendering the core experience or responding to
-user input.
+user-blocking is the highest priority, and is meant to be
+used for tasks that are blocking the user's ability to interact with the page, such as rendering the
+core experience or responding to user input.
-user-visible is the second highest
-priority, and is meant to be used for tasks that visible to the user but not
-necessarily blocking user actions, such as rendering secondary parts of the
-page. This is the default priority.
+user-visible is the second highest priority, and is meant to
+be used for tasks that visible to the user but not necessarily blocking user actions, such as
+rendering secondary parts of the page. This is the default priority.
-background is the lowest priority, and
-is meant to be used for tasks that are not time-critical, such as background
-log processing or initializing certain third party libraries.
+background is the lowest priority, and is meant to be used
+for tasks that are not time-critical, such as background log processing or initializing certain
+third party libraries.
-Note: Tasks scheduled through a given {{Scheduler}} run in *strict priority
-order*, meaning the scheduler will always run "{{TaskPriority/user-blocking}}"
-tasks before "{{TaskPriority/user-visible}}" tasks, which in turn always run
-before "{{TaskPriority/background}}" tasks.
+Note: Tasks scheduled through a given {{Scheduler}} run in *strict priority order*, meaning the
+scheduler will always run "{{TaskPriority/user-blocking}}" tasks before
+"{{TaskPriority/user-visible}}" tasks, which in turn always run before "{{TaskPriority/background}}"
+tasks.
{{TaskPriority}} |p1| is less than
@@ -41,8 +37,7 @@ before "{{TaskPriority/background}}" tasks.
-The `Scheduler` Interface {#sec-scheduler}
----------------------
+## The `Scheduler` Interface ## {#sec-scheduler}
dictionary SchedulerPostTaskOptions {
@@ -60,112 +55,96 @@ The `Scheduler` Interface {#sec-scheduler}
};
-Note: The {{SchedulerPostTaskOptions/signal}} option can be either an
-{{AbortSignal}} or a {{TaskSignal}}, but is defined as an {{AbortSignal}} since
-it is a superclass of {{TaskSignal}}. For cases where the priority might
-change, a {{TaskSignal}} is needed. But for cases where only cancellation is
-needed, an {{AbortSignal}} would suffice, potentially making it easier to
-integrate the API into existing code that uses {{AbortSignal|AbortSignals}}.
+Note: The {{SchedulerPostTaskOptions/signal}} option can be either an {{AbortSignal}} or a
+{{TaskSignal}}, but is defined as an {{AbortSignal}} since it is a superclass of {{TaskSignal}}. For
+cases where the priority might change, a {{TaskSignal}} is needed. But for cases where only
+cancellation is needed, an {{AbortSignal}} would suffice, potentially making it easier to integrate
+the API into existing code that uses {{AbortSignal|AbortSignals}}.
result = scheduler . {{Scheduler/postTask()|postTask}}( |callback|, |options| )-
-
Returns a promise that is fulfilled with the return value of |callback|,
- or rejected with the {{AbortSignal}}'s [=AbortSignal/abort reason=] if the
- task is aborted. If |callback| throws an error during execution, the promise
- returned by {{Scheduler/postTask()}} will be rejected with that error.
+
Returns a promise that is fulfilled with the return value of |callback|, or rejected with the
+ {{AbortSignal}}'s [=AbortSignal/abort reason=] if the task is aborted. If |callback| throws an
+ error during execution, the promise returned by {{Scheduler/postTask()}} will be rejected with
+ that error.
-
The task's {{TaskPriority|priority}} is determined by the combination of
- |option|'s {{SchedulerPostTaskOptions/priority}} and
- {{SchedulerPostTaskOptions/signal}}:
+
The task's {{TaskPriority|priority}} is determined by the combination of |option|'s
+ {{SchedulerPostTaskOptions/priority}} and {{SchedulerPostTaskOptions/signal}}:
- - If |option|'s {{SchedulerPostTaskOptions/priority}} is specified, then
- that {{TaskPriority}} will be used to schedule the task, and the task's
- priority is immutable.
+ If |option|'s {{SchedulerPostTaskOptions/priority}} is specified, then that
+ {{TaskPriority}} will be used to schedule the task, and the task's priority is immutable.
-
- Otherwise, if |option|'s {{SchedulerPostTaskOptions/signal}} is
- specified and is a {{TaskSignal}} object, then the task's priority is
- determined by |option|'s {{SchedulerPostTaskOptions/signal}}'s
- [=TaskSignal/priority=]. In this case the task's priority is *dynamic*,
- and can be changed by calling {{TaskController/setPriority()|controller.setPriority()}}
- for the associated {{TaskController}}.
+ Otherwise, if |option|'s {{SchedulerPostTaskOptions/signal}} is specified and is a
+ {{TaskSignal}} object, then the task's priority is determined by |option|'s
+ {{SchedulerPostTaskOptions/signal}}'s [=TaskSignal/priority=]. In this case the task's
+ priority is *dynamic*, and can be changed by calling
+ {{TaskController/setPriority()|controller.setPriority()}} for the associated
+ {{TaskController}}.
-
- Otherwise, the task's priority defaults to "{{TaskPriority/user-visible}}".
-
+ Otherwise, the task's priority defaults to "{{TaskPriority/user-visible}}".
+
If |option|'s {{SchedulerPostTaskOptions/signal}} is specified, then the
- {{SchedulerPostTaskOptions/signal}} is used by the {{Scheduler}} to
- determine if the task is aborted.
+ {{SchedulerPostTaskOptions/signal}} is used by the {{Scheduler}} to determine if the task is
+ aborted.
-
If |option|'s {{SchedulerPostTaskOptions/delay}} is specified and greater
- than 0, then the execution of the task will be delayed for at least
- {{SchedulerPostTaskOptions/delay}} milliseconds.
+
If |option|'s {{SchedulerPostTaskOptions/delay}} is specified and greater than 0, then the
+ execution of the task will be delayed for at least {{SchedulerPostTaskOptions/delay}}
+ milliseconds.
A {{Scheduler}} object has an associated static priority task queue map,
-which is a [=map=] from {{TaskPriority}} to [=scheduler task queue=]. This map
-is initialized to a new empty [=map=].
+which is a [=map=] from {{TaskPriority}} to [=scheduler task queue=]. This map is initialized to a
+new empty [=map=].
A {{Scheduler}} object has an associated dynamic priority task queue map,
-which is a [=map=] from {{TaskSignal}} to [=scheduler task queue=]. This map is
-initialized to a new empty [=map=].
-
-Note: We implement *dynamic prioritization* by enqueuing tasks associated with
-a specific {{TaskSignal}} into the same [=scheduler task queue=], and changing
-that queue's priority in response to `prioritychange` events. The
-[=Scheduler/dynamic priority task queue map=] holds the
-[=scheduler task queues=] whose priorities can change, and the map key is the
-{{TaskSignal}} which all tasks in the queue are associated with.
+which is a [=map=] from {{TaskSignal}} to [=scheduler task queue=]. This map is initialized to a new
+empty [=map=].
+
+Note: We implement *dynamic prioritization* by enqueuing tasks associated with a specific
+{{TaskSignal}} into the same [=scheduler task queue=], and changing that queue's priority in
+response to `prioritychange` events. The [=Scheduler/dynamic priority task queue map=] holds the
+[=scheduler task queues=] whose priorities can change, and the map key is the {{TaskSignal}} which
+all tasks in the queue are associated with.
-The values of the [=Scheduler/static priority task queue map=] are
-[=scheduler task queues=] whose priorities do not change. Tasks with *static
-priorities* — those that were scheduled with an explicit
-{{SchedulerPostTaskOptions/priority}} option or a
-{{SchedulerPostTaskOptions/signal}} option that is null or is an {{AbortSignal}}
-— are placed in these queues, based on {{TaskPriority}}, which is the
-key for the map.
+The values of the [=Scheduler/static priority task queue map=] are [=scheduler task queues=] whose
+priorities do not change. Tasks with *static priorities* — those that were scheduled with an
+explicit {{SchedulerPostTaskOptions/priority}} option or a {{SchedulerPostTaskOptions/signal}}
+option that is null or is an {{AbortSignal}} — are placed in these queues, based on
+{{TaskPriority}}, which is the key for the map.
-An alternative, and logicially equivalent implementation, would be to maintain a
-single per-{{TaskPriority}} [=scheduler task queue=], and move tasks between
-[=scheduler task queues=] in response to a {{TaskSignal}}'s
-[=TaskSignal/priority=] changing, inserting based on
-[=scheduler task/enqueue order=]. This approach would simplify
-[=selecting the task queue of the next scheduler task=], but make priority
-changes more complex.
-
-
-A {{Scheduler}} object has a numeric next enqueue order
-which is initialized to 1.
-
-Note: The [=Scheduler/next enqueue order=] is a strictly increasing number that
-is used to determine task execution order across [=scheduler task queues=] of the
-same {{TaskPriority}} within the same {{Scheduler}}. A logically equivalent
-alternative would be to place the [=Scheduler/next enqueue order=] on the
-[=event loop=], since the only requirements are that the number be strictly
+An alternative, and logicially equivalent implementation, would be to maintain a single
+per-{{TaskPriority}} [=scheduler task queue=], and move tasks between [=scheduler task queues=] in
+response to a {{TaskSignal}}'s [=TaskSignal/priority=] changing, inserting based on [=scheduler
+task/enqueue order=]. This approach would simplify [=selecting the task queue of the next scheduler
+task=], but make priority changes more complex.
+
+
+A {{Scheduler}} object has a numeric next enqueue order which is
+initialized to 1.
+
+Note: The [=Scheduler/next enqueue order=] is a strictly increasing number that is used to determine
+task execution order across [=scheduler task queues=] of the same {{TaskPriority}} within the same
+{{Scheduler}}. A logically equivalent alternative would be to place the [=Scheduler/next enqueue
+order=] on the [=event loop=], since the only requirements are that the number be strictly
increasing and not be repeated within a {{Scheduler}}.
Issue: Would it be simpler to just use a timestamp here?
The postTask(|callback|, |options|)
-method steps are to return the result of [=scheduling a postTask task=] for [=this=]
-given |callback| and |options|.
+method steps are to return the result of [=scheduling a postTask task=] for [=this=] given
+|callback| and |options|.
-Definitions {#sec-scheduling-tasks-definitions}
----------------------
+## Definitions ## {#sec-scheduling-tasks-definitions}
A scheduler task is a [=/task=] with an additional numeric
enqueue order [=struct/item=], initially set to 0.
-A [=scheduler task=] |t1| is older than
-[=scheduler task=] |t2| if |t1|'s [=scheduler task/enqueue order=] less than |t2|'s
-[=scheduler task/enqueue order=].
-
-
-
The following [=task sources=] are defined as scheduler task sources,
and must only be used for [=scheduler tasks=].
@@ -181,9 +160,16 @@ A scheduler task queue is a [=struct=] with the following [=struct/it
: tasks
:: A [=set=] of [=scheduler tasks=].
+
+## Processing Model ## {#sec-scheduling-tasks-processing-model}
+
+
+ A [=scheduler task=] |t1| is older than [=scheduler task=] |t2| if
+ |t1|'s [=scheduler task/enqueue order=] less than |t2|'s [=scheduler task/enqueue order=].
+
+
- To create a scheduler task queue
- with {{TaskPriority}} |priority|:
+ To create a scheduler task queue with {{TaskPriority}} |priority|:
1. Let |queue| be a new [=scheduler task queue=].
1. Set |queue|'s [=scheduler task queue/priority=] to |priority|.
@@ -191,173 +177,153 @@ A scheduler task queue is a [=struct=] with the following [=struct/it
1. Return |queue|.
-A [=scheduler task queue=] |queue|'s first runnable task
-is the first [=scheduler task=] in |queue|'s [=scheduler task queue/tasks=] that is
-[=task/runnable=].
-
-Processing Model {#sec-scheduling-tasks-processing-model}
----------------------
+
+ A [=scheduler task queue=] |queue|'s first runnable task is
+ the first [=scheduler task=] in |queue|'s [=scheduler task queue/tasks=] that is
+ [=task/runnable=].
+
### Queueing and Removing Scheduler Tasks ### {#sec-queuing-scheduler-tasks}
-
- To queue a scheduler task
- on a [=scheduler task queue=] |queue|, which performs a series of steps |steps|,
- given a numeric |enqueue order|, a [=task source=] |source|, and a [=document=] |document|:
+
+ To queue a scheduler task on a [=scheduler task queue=] |queue|, which performs a
+ series of steps |steps|, given a numeric |enqueue order|, a [=task source=] |source|, and a
+ [=document=] |document|:
1. Let |task| be a new [=scheduler task=].
1. Set |task|'s [=scheduler task/enqueue order=] to |enqueue order|.
1. Set |task|'s steps to |steps|.
1. Set |task|'s source to |source|.
1. Set |task|'s document to |document|.
- 1. Set |task|'s script evaluation environment settings
- object set to a new empty [=set=].
+ 1. Set |task|'s script evaluation environment settings object set to a
+ new empty [=set=].
1. [=set/Append=] |task| to |queue|'s [=scheduler task queue/tasks=].
1. Return |task|.
- Issue: We should consider refactoring the HTML spec to add a constructor for
- [=/task=]. One problem is we need the new task to be a [=scheduler task=]
- rather than a [=/task=].
+ Issue: We should consider refactoring the HTML spec to add a constructor for [=/task=]. One
+ problem is we need the new task to be a [=scheduler task=] rather than a [=/task=].
- To remove a [=scheduler task=] |task| from
- [=scheduler task queue=] |queue|, [=set/remove=] |task| from |queue|'s
- [=scheduler task queue/tasks=].
+ To remove a [=scheduler task=] |task| from [=scheduler task
+ queue=] |queue|, [=set/remove=] |task| from |queue|'s [=scheduler task queue/tasks=].
### Scheduling Tasks ### {#sec-scheduler-alg-scheduling-tasks}
-
- To schedule a postTask task
- for {{Scheduler}} |scheduler| given a {{SchedulerPostTaskCallback}} |callback| and
- {{SchedulerPostTaskOptions}} |options|, run the following steps:
+
+ To schedule a postTask task for {{Scheduler}} |scheduler| given a
+ {{SchedulerPostTaskCallback}} |callback| and {{SchedulerPostTaskOptions}} |options|:
1. Let |result| be [=a new promise=].
1. Let |signal| be |options|["{{SchedulerPostTaskOptions/signal}}"] if
- |options|["{{SchedulerPostTaskOptions/signal}}"] [=map/exists=], or
- otherwise null.
- 1. If |signal| is not null and it is [=AbortSignal/aborted=], then
- [=reject=] |result| with |signal|'s [=AbortSignal/abort reason=] and return
- |result|.
+ |options|["{{SchedulerPostTaskOptions/signal}}"] [=map/exists=], or otherwise null.
+ 1. If |signal| is not null and it is [=AbortSignal/aborted=], then [=reject=] |result| with
+ |signal|'s [=AbortSignal/abort reason=] and return |result|.
1. Let |priority| be |options|["{{SchedulerPostTaskOptions/priority}}"] if
- |options|["{{SchedulerPostTaskOptions/priority}}"] [=map/exists=], or
- otherwise null.
- 1. Let |queue| be the result of [=selecting the scheduler task queue=] for
- |scheduler| given |signal| and |priority|.
+ |options|["{{SchedulerPostTaskOptions/priority}}"] [=map/exists=], or otherwise null.
+ 1. Let |queue| be the result of [=selecting the scheduler task queue=] for |scheduler| given
+ |signal| and |priority|.
1. Let |delay| be |options|["{{SchedulerPostTaskOptions/delay}}"].
- 1. If |delay| is greater than 0, then [=run steps after a timeout=] given
- |scheduler|'s [=relevant global object=], "`scheduler-postTask`",
- |delay|, and the following steps:
- 1. [=Schedule a task to invoke a callback=] for |scheduler| given |queue|,
- |signal|, |callback|, and |result|.
- 1. Otherwise, [=schedule a task to invoke a callback=] for |scheduler| given
- |queue|, |signal|, |callback|, and |result|.
+ 1. If |delay| is greater than 0, then [=run steps after a timeout=] given |scheduler|'s [=relevant
+ global object=], "`scheduler-postTask`", |delay|, and the following steps:
+ 1. [=Schedule a task to invoke a callback=] for |scheduler| given |queue|, |signal|, |callback|,
+ and |result|.
+ 1. Otherwise, [=schedule a task to invoke a callback=] for |scheduler| given |queue|, |signal|,
+ |callback|, and |result|.
1. Return |result|.
-Issue: [=Run steps after a timeout=] doesn't necessarily account for suspension;
-see [whatwg/html#5925](https://github.com/whatwg/html/issues/5925).
+Issue: [=Run steps after a timeout=] doesn't necessarily account for suspension; see
+[whatwg/html#5925](https://github.com/whatwg/html/issues/5925).
-
- To select the scheduler task queue
- for a {{Scheduler}} |scheduler| given an {{AbortSignal}} or null |signal|, and
- a {{TaskPriority}} or null |priority|:
+
+ To select the scheduler task queue for a {{Scheduler}} |scheduler| given an
+ {{AbortSignal}} or null |signal|, and a {{TaskPriority}} or null |priority|:
1. If |priority| is null, |signal| is not null and [=implements=] the {{TaskSignal}} interface,
and |signal| [=TaskSignal/has fixed priority=], then set |priority| to |signal|'s
[=TaskSignal/priority=].
1. If |priority| is null and |signal| is not null and [=implements=] the {{TaskSignal}} interface,
then
- 1. If |scheduler|'s [=Scheduler/dynamic priority task queue map=] does not
- [=map/contain=] |signal|, then
- 1. Let |queue| be the result of [=creating a scheduler task queue=] given
- |signal|'s [=TaskSignal/priority=].
+ 1. If |scheduler|'s [=Scheduler/dynamic priority task queue map=] does not [=map/contain=]
+ |signal|, then
+ 1. Let |queue| be the result of [=creating a scheduler task queue=] given |signal|'s
+ [=TaskSignal/priority=].
1. Set [=Scheduler/dynamic priority task queue map=][|signal|] to |queue|.
- 1. [=TaskSignal/Add a priority change algorithm=] to |signal| that
- runs the following steps:
- 1. Set |queue|'s [=scheduler task queue/priority=] to |signal|'s
- {{TaskSignal/priority}}.
+ 1. [=TaskSignal/Add a priority change algorithm=] to |signal| that runs the following steps:
+ 1. Set |queue|'s [=scheduler task queue/priority=] to |signal|'s {{TaskSignal/priority}}.
1. Return [=Scheduler/dynamic priority task queue map=][|signal|].
1. Otherwise |priority| is used to determine the task queue:
1. If |priority| is null, set |priority| to "{{TaskPriority/user-visible}}".
- 1. If |scheduler|'s [=Scheduler/static priority task queue map=] does not
- [=map/contain=] |priority|, then
- 1. Let |queue| be the result of [=creating a scheduler task queue=] given
- |priority|.
+ 1. If |scheduler|'s [=Scheduler/static priority task queue map=] does not [=map/contain=]
+ |priority|, then
+ 1. Let |queue| be the result of [=creating a scheduler task queue=] given |priority|.
1. Set [=Scheduler/static priority task queue map=][|priority|] to |queue|.
1. Return [=Scheduler/static priority task queue map=][|priority|].
- To schedule a task to invoke a callback for {{Scheduler}}
- |scheduler| given a [=scheduler task queue=] |queue|, an {{AbortSignal}} or
- null |signal|, a SchedulerPostTaskCallback |callback|, and a promise |result|:
+ To schedule a task to invoke a callback for {{Scheduler}} |scheduler| given a
+ [=scheduler task queue=] |queue|, an {{AbortSignal}} or null |signal|, a SchedulerPostTaskCallback
+ |callback|, and a promise |result|:
1. Let |global| be the [=relevant global object=] for |scheduler|.
- 1. Let |document| be |global|'s associated `Document`
- if |global| is a {{Window}} object; otherwise null.
+ 1. Let |document| be |global|'s associated `Document` if |global| is
+ a {{Window}} object; otherwise null.
1. Let |enqueue order| be |scheduler|'s [=Scheduler/next enqueue order=].
1. Increment |scheduler|'s [=Scheduler/next enqueue order=] by 1.
- 1. Let |task| be the result of [=queuing a scheduler task=] on |queue| given
- |enqueue order|, [=the posted task task source=], and |document|, and that
- performs the following steps:
- 1. Let |callback result| be the result of [=invoking=] |callback|. If that
- threw an exception, then [=reject=] |result| with that, otherwise resolve
- |result| with |callback result|.
- 1. If |signal| is not null, then [=AbortSignal/add|add the following=] abort
- steps to it:
+ 1. Let |task| be the result of [=queuing a scheduler task=] on |queue| given |enqueue order|,
+ [=the posted task task source=], and |document|, and that performs the following steps:
+ 1. Let |callback result| be the result of [=invoking=] |callback|. If that threw an exception,
+ then [=reject=] |result| with that, otherwise resolve |result| with |callback result|.
+ 1. If |signal| is not null, then [=AbortSignal/add|add the following=] abort steps to it:
1. [=scheduler task queue/Remove=] |task| from |queue|.
1. [=Reject=] |result| with |signal|'s [=AbortSignal/abort reason=].
- Issue: Because this algorithm can be called from [=in parallel=] steps, parts
- of this and other algorithms are racy. Specifically, the
- [=Scheduler/next enqueue order=] should be updated atomically, and accessing
- the [=scheduler task queues=] should occur atomically. The latter also affects
- the event loop task queues (see [this issue](https://github.com/whatwg/html/issues/6475)).
+ Issue: Because this algorithm can be called from [=in parallel=] steps, parts of this and other
+ algorithms are racy. Specifically, the [=Scheduler/next enqueue order=] should be updated
+ atomically, and accessing the [=scheduler task queues=] should occur atomically. The latter also
+ affects the event loop task queues (see [this issue](https://github.com/whatwg/html/issues/6475)).
### Selecting the Next Task to Run ### {#sec-scheduler-alg-select-next-task}
-
- A {{Scheduler}} |scheduler| has a runnable task
- if the result of [=getting the runnable task queues=] for |scheduler| is non-[=list/empty=].
+
+ A {{Scheduler}} |scheduler| has a runnable
+ task if the result of [=getting the runnable task queues=] for |scheduler| is
+ non-[=list/empty=].
-
- To get the runnable task queues
- for a {{Scheduler}} |scheduler|, run the following steps:
-
- 1. Let |queues| be the result of [=map/get the values|getting the values=] of
- |scheduler|'s [=Scheduler/static priority task queue map=].
- 1. [=list/Extend=] |queues| with the result of [=map/get the values|getting the values=]
- of |scheduler|'s [=Scheduler/dynamic priority task queue map=].
- 1. [=list/Remove=] from |queues| any |queue| such that |queue|'s [=scheduler task queue/tasks=]
- do not contain a [=task/runnable=] [=scheduler task=].
+
+ To get the runnable task queues for a {{Scheduler}} |scheduler|:
+
+ 1. Let |queues| be the result of [=map/get the values|getting the values=] of |scheduler|'s
+ [=Scheduler/static priority task queue map=].
+ 1. [=list/Extend=] |queues| with the result of [=map/get the values|getting the values=] of
+ |scheduler|'s [=Scheduler/dynamic priority task queue map=].
+ 1. [=list/Remove=] from |queues| any |queue| such that |queue|'s [=scheduler task queue/tasks=] do
+ not contain a [=task/runnable=] [=scheduler task=].
1. Return |queues|.
- The result of selecting the task queue of the next scheduler task
- for {{Scheduler}} |scheduler| is a [=set=] of [=scheduler tasks=] as defined
- by the following steps:
+ The result of selecting the task queue of the next scheduler task for {{Scheduler}}
+ |scheduler| is a [=set=] of [=scheduler tasks=] as defined by the following steps:
1. Let |queues| be the result of [=getting the runnable task queues=] for |scheduler|.
1. If |queues| is [=list/empty=] return null.
1. [=set/Remove=] from |queues| any |queue| such that |queue|'s [=scheduler task queue/priority=]
is [=TaskPriority/less than=] any other [=set/item=] of |queues|.
- 1. Let |queue| be the [=scheduler task queue=] in |queues| whose
- [=scheduler task queue/first runnable task=] is the
- [=scheduler task/older than|oldest=].
+ 1. Let |queue| be the [=scheduler task queue=] in |queues| whose [=scheduler task queue/first
+ runnable task=] is the [=scheduler task/older than|oldest=].
Two tasks cannot have the same age since [=scheduler task/enqueue order=]
is unique.
1. Return |queue|'s [=scheduler task queue/tasks=].
- Note: The next task to run is the oldest, highest priority [=task/runnable=]
- [=scheduler task=].
+ Note: The next task to run is the oldest, highest priority [=task/runnable=] [=scheduler task=].
-Examples {#sec-scheduling-tasks-examples}
----------------------
+## Examples ## {#sec-scheduling-tasks-examples}
**TODO**(shaseley): Add examples.
diff --git a/spec/security.md b/spec/security.md
index 8d20ab9..23d3c54 100644
--- a/spec/security.md
+++ b/spec/security.md
@@ -1,5 +1,4 @@
-Security Considerations {#sec-security}
-=====================
+# Security Considerations # {#sec-security}
*This section is non-normative.*
@@ -9,8 +8,7 @@ whether or not any information is potentially leaked between origins by
timing-based side-channel attacks.
-`postTask` as a High-Resolution Timing Source {#sec-security-high-res-timer}
----------------------
+## `postTask` as a High-Resolution Timing Source ## {#sec-security-high-res-timer}
This API cannot be used as a high-resolution timing source. Like
@@ -22,8 +20,7 @@ their delay expires and not run instantly, the precision available to callers
is further reduced.
-Monitoring Another Origin's Tasks {#sec-security-monitoring-tasks}
----------------------
+## Monitoring Another Origin's Tasks ## {#sec-security-monitoring-tasks}
The second consideration is whether {{Scheduler/postTask()}} leaks any