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// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef TaskRunnerHelper_h
#define TaskRunnerHelper_h
#include "core/CoreExport.h"
#include "wtf/Allocator.h"
#include "wtf/HashTraits.h"
namespace blink {
class Document;
class ExecutionContext;
class LocalFrame;
class ScriptState;
class WebTaskRunner;
enum class TaskType : unsigned {
// Speced tasks and related internal tasks should be posted to one of
// the following task runners. These task runners may be throttled.
// https://html.spec.whatwg.org/multipage/webappapis.html#generic-task-sources
//
// This task source is used for features that react to DOM manipulations, such
// as things that happen in a non-blocking fashion when an element is inserted
// into the document.
DOMManipulation,
// This task source is used for features that react to user interaction, for
// example keyboard or mouse input. Events sent in response to user input
// (e.g. click events) must be fired using tasks queued with the user
// interaction task source.
UserInteraction,
// This task source is used for features that trigger in response to network
// activity.
Networking,
// This task source is used to queue calls to history.back() and similar APIs.
HistoryTraversal,
// https://html.spec.whatwg.org/multipage/embedded-content.html#the-embed-element
// This task source is used for the embed element setup steps.
Embed,
// https://html.spec.whatwg.org/multipage/embedded-content.html#media-elements
// This task source is used for all tasks queued in the [Media elements]
// section and subsections of the spec unless explicitly specified otherwise.
MediaElementEvent,
// https://html.spec.whatwg.org/multipage/scripting.html#the-canvas-element
// This task source is used to invoke the result callback of
// HTMLCanvasElement.toBlob().
CanvasBlobSerialization,
// https://html.spec.whatwg.org/multipage/webappapis.html#event-loop-processing-model
// This task source is used when an algorithm requires a microtask to be
// queued.
Microtask,
// https://html.spec.whatwg.org/multipage/webappapis.html#timers
// This task source is used to queue tasks queued by setInterval() and similar
// APIs.
Timer,
// https://html.spec.whatwg.org/multipage/comms.html#sse-processing-model
// This task source is used for any tasks that are queued by EventSource
// objects.
RemoteEvent,
// https://html.spec.whatwg.org/multipage/comms.html#feedback-from-the-protocol
// The task source for all tasks queued in the [WebSocket] section of the
// spec.
WebSocket,
// https://html.spec.whatwg.org/multipage/comms.html#web-messaging
// This task source is used for the tasks in cross-document messaging.
PostedMessage,
// https://html.spec.whatwg.org/multipage/comms.html#message-ports
UnshippedPortMessage,
// https://www.w3.org/TR/FileAPI/#blobreader-task-source
// This task source is used for all tasks queued in the FileAPI spec to read
// byte sequences associated with Blob and File objects.
FileReading,
// https://www.w3.org/TR/IndexedDB/#request-api
DatabaseAccess,
// https://w3c.github.io/presentation-api/#common-idioms
// This task source is used for all tasks in the Presentation API spec.
Presentation,
// https://www.w3.org/TR/2016/WD-generic-sensor-20160830/#sensor-task-source
// This task source is used for all tasks in the Sensor API spec.
Sensor,
// Use MiscPlatformAPI for a task that is defined in the spec but is not yet
// associated with any specific task runner in the spec. MiscPlatformAPI is
// not encouraged for stable and matured APIs. The spec should define the task
// runner explicitly.
// The task runner may be throttled.
MiscPlatformAPI,
// Other internal tasks that cannot fit any of the above task runners
// can be posted here, but the usage is not encouraged. The task runner
// may be throttled.
//
// UnspecedLoading type should be used for all tasks associated with
// loading page content, UnspecedTimer should be used for all other purposes.
UnspecedTimer,
UnspecedLoading,
// Tasks that must not be throttled should be posted here, but the usage
// should be very limited.
Unthrottled,
};
// HashTraits for TaskType.
struct TaskTypeTraits : WTF::GenericHashTraits<TaskType> {
static const bool emptyValueIsZero = false;
static TaskType emptyValue() { return static_cast<TaskType>(-1); }
static void constructDeletedValue(TaskType& slot, bool) {
slot = static_cast<TaskType>(-2);
}
static bool isDeletedValue(TaskType value) {
return value == static_cast<TaskType>(-2);
}
};
// A set of helper functions to get a WebTaskRunner for TaskType and a context
// object. The posted tasks are guaranteed to run in a sequence if they have the
// same TaskType and the context objects belong to the same frame.
class CORE_EXPORT TaskRunnerHelper final {
STATIC_ONLY(TaskRunnerHelper);
public:
static RefPtr<WebTaskRunner> get(TaskType, LocalFrame*);
static RefPtr<WebTaskRunner> get(TaskType, Document*);
static RefPtr<WebTaskRunner> get(TaskType, ExecutionContext*);
static RefPtr<WebTaskRunner> get(TaskType, ScriptState*);
};
} // namespace blink
#endif
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