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/*
* Copyright (C) 2010 Google, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_SCRIPT_SCRIPT_RUNNER_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_SCRIPT_SCRIPT_RUNNER_H_
#include "base/task/single_thread_task_runner.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/script/pending_script.h"
#include "third_party/blink/renderer/platform/bindings/name_client.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_deque.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_hash_map.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_hash_set.h"
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"
#include "third_party/blink/renderer/platform/wtf/deque.h"
namespace blink {
class Document;
class CORE_EXPORT ScriptRunner final : public GarbageCollected<ScriptRunner>,
public PendingScriptClient,
public NameClient {
public:
explicit ScriptRunner(Document*);
~ScriptRunner() override = default;
ScriptRunner(const ScriptRunner&) = delete;
ScriptRunner& operator=(const ScriptRunner&) = delete;
// Delays script evaluation after `ScriptRunnerDelayer::Activate()` until
// `ScriptRunnerDelayer::Deactivate()`.
//
// Each `DelayReason` value represents one reason to delay, and there should
// be at most one active `ScriptRunnerDelayer` for each `ScriptRunnerDelayer`
// for each `ScriptRunner`.
//
// Each script can choose to wait or not to wait for each `DelayReason`, and
// are evaluated after all of its relevant `ScriptRunnerDelayer`s are
// deactivated.
//
// This can be spec-conformant (pretending that the loading of async scripts
// are not completed until `ScriptRunnerDelayer`s are deactivated), but be
// careful to avoid deadlocks and infinite delays.
//
// Currently this only affects async scripts and not in-order scripts.
enum class DelayReason : uint8_t {
// Script is loaded. Should be enabled for all scripts.
kLoad = 1 << 0,
// Milestone is reached as defined by https://crbug.com/1340837.
kMilestone = 1 << 1,
kTest1 = 1 << 6,
kTest2 = 1 << 7,
};
using DelayReasons = std::underlying_type<DelayReason>::type;
void QueueScriptForExecution(PendingScript*, DelayReasons);
bool IsActive(DelayReason delay_reason) const {
return active_delay_reasons_ & static_cast<DelayReasons>(delay_reason);
}
void SetTaskRunnerForTesting(base::SingleThreadTaskRunner* task_runner) {
task_runner_ = task_runner;
}
// Returns true until all force in-order scripts are evaluated.
// pending_force_in_order_scripts_ can be empty a little earlier than that.
bool HasForceInOrderScripts() const {
return pending_force_in_order_scripts_count_ > 0;
}
void Trace(Visitor*) const override;
const char* NameInHeapSnapshot() const override { return "ScriptRunner"; }
// PendingScriptClient
void PendingScriptFinished(PendingScript*) override;
void ExecuteAsyncPendingScript(PendingScript* pending_script,
base::TimeTicks ready_to_evaluate_time);
void ExecuteForceInOrderPendingScript(PendingScript*);
void ExecuteParserBlockingScriptsBlockedByForceInOrder();
private:
// Execute the given pending script.
void ExecutePendingScript(PendingScript*);
friend class ScriptRunnerDelayer;
void AddDelayReason(DelayReason);
void RemoveDelayReason(DelayReason);
void RemoveDelayReasonFromScript(PendingScript*, DelayReason);
// https://html.spec.whatwg.org/C/#list-of-scripts-that-will-execute-in-order-as-soon-as-possible
HeapDeque<Member<PendingScript>> pending_in_order_scripts_;
// https://html.spec.whatwg.org/C/#set-of-scripts-that-will-execute-as-soon-as-possible
// The value represents the `DelayReason`s that the script is waiting for
// before its evaluation.
HeapHashMap<Member<PendingScript>, DelayReasons> pending_async_scripts_;
Member<Document> document_;
HeapDeque<Member<PendingScript>> pending_force_in_order_scripts_;
// The number of force in-order scripts that aren't yet evaluated. This is
// different from pending_force_in_order_scripts_.size() == the number of
// force in-order scripts that aren't yet scheduled to evaluate.
wtf_size_t pending_force_in_order_scripts_count_ = 0;
scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
scoped_refptr<base::SingleThreadTaskRunner> low_priority_task_runner_;
DelayReasons active_delay_reasons_ = 0;
};
class CORE_EXPORT ScriptRunnerDelayer final
: public GarbageCollected<ScriptRunnerDelayer> {
public:
ScriptRunnerDelayer(ScriptRunner*, ScriptRunner::DelayReason);
~ScriptRunnerDelayer() = default;
void Activate();
void Deactivate();
ScriptRunnerDelayer(const ScriptRunnerDelayer&) = delete;
ScriptRunnerDelayer& operator=(const ScriptRunnerDelayer&) = delete;
void Trace(Visitor*) const;
private:
WeakMember<ScriptRunner> script_runner_;
const ScriptRunner::DelayReason delay_reason_;
bool activated_ = false;
};
// This function is exported for testing purposes only.
void CORE_EXPORT PostTaskWithLowPriorityUntilTimeoutForTesting(
const base::Location& from_here,
base::OnceClosure task,
base::TimeDelta timeout,
scoped_refptr<base::SingleThreadTaskRunner> lower_priority_task_runner,
scoped_refptr<base::SingleThreadTaskRunner> normal_priority_task_runner);
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_SCRIPT_SCRIPT_RUNNER_H_
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