| // Copyright 2018 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. |
| |
| #include "third_party/blink/renderer/core/dom/abort_signal.h" |
| |
| #include <utility> |
| |
| #include "base/callback.h" |
| #include "third_party/blink/renderer/core/dom/events/event.h" |
| #include "third_party/blink/renderer/core/event_target_names.h" |
| #include "third_party/blink/renderer/core/event_type_names.h" |
| #include "third_party/blink/renderer/core/execution_context/execution_context.h" |
| #include "third_party/blink/renderer/platform/heap/persistent.h" |
| #include "third_party/blink/renderer/platform/heap/visitor.h" |
| #include "third_party/blink/renderer/platform/wtf/functional.h" |
| #include "third_party/blink/renderer/platform/wtf/text/atomic_string.h" |
| |
| namespace blink { |
| |
| AbortSignal::AbortSignal(ExecutionContext* execution_context) |
| : execution_context_(execution_context) {} |
| AbortSignal::~AbortSignal() = default; |
| |
| const AtomicString& AbortSignal::InterfaceName() const { |
| return EventTargetNames::AbortSignal; |
| } |
| |
| ExecutionContext* AbortSignal::GetExecutionContext() const { |
| return execution_context_.Get(); |
| } |
| |
| void AbortSignal::AddAlgorithm(base::OnceClosure algorithm) { |
| if (aborted_flag_) |
| return; |
| abort_algorithms_.push_back(std::move(algorithm)); |
| } |
| |
| void AbortSignal::SignalAbort() { |
| if (aborted_flag_) |
| return; |
| aborted_flag_ = true; |
| for (base::OnceClosure& closure : abort_algorithms_) { |
| std::move(closure).Run(); |
| } |
| abort_algorithms_.clear(); |
| DispatchEvent(*Event::Create(EventTypeNames::abort)); |
| } |
| |
| void AbortSignal::Follow(AbortSignal* parentSignal) { |
| if (aborted_flag_) |
| return; |
| if (parentSignal->aborted_flag_) |
| SignalAbort(); |
| |
| // Unlike the usual practice for AddAlgorithm(), we don't use a weak pointer |
| // here. To see why, consider the following object graph: |
| // |
| // controller --owns--> signal1 -?-> signal2 -?-> signal3 <--owns-- request |
| // |
| // It's easy to create chained signals like this using the Request |
| // constructor. If the -?-> pointers were weak, then |signal2| could be |
| // collected even though |controller| and |request| were still |
| // referenced. This would prevent controller.abort() from working. So the |
| // pointers need to be strong. This won't artificially extend the lifetime of |
| // |request|, because the pointer to it in the closure held by |signal3| is |
| // still weak. |
| parentSignal->AddAlgorithm( |
| WTF::Bind(&AbortSignal::SignalAbort, WrapPersistent(this))); |
| } |
| |
| void AbortSignal::Trace(Visitor* visitor) { |
| visitor->Trace(execution_context_); |
| EventTargetWithInlineData::Trace(visitor); |
| } |
| |
| } // namespace blink |