Source/WebCore/worklets/PaintWorkletGlobalScope.h

/*
 * Copyright (C) 2018-2020 Apple 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,
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 */

#pragma once

#if ENABLE(CSS_PAINTING_API)

#include "CSSPaintCallback.h"
#include "WorkletGlobalScope.h"
#include <JavaScriptCore/JSObject.h>
#include <JavaScriptCore/Strong.h>
#include <wtf/Lock.h>

namespace JSC {
class JSObject;
class VM;
} // namespace JSC

namespace WebCore {
class JSDOMGlobalObject;

class PaintWorkletGlobalScope final : public WorkletGlobalScope {
    WTF_MAKE_ISO_ALLOCATED(PaintWorkletGlobalScope);
public:
    static RefPtr<PaintWorkletGlobalScope> tryCreate(Document&, ScriptSourceCode&&);

    ExceptionOr<void> registerPaint(JSC::JSGlobalObject&, const AtomString& name, JSC::Strong<JSC::JSObject> paintConstructor);
    double devicePixelRatio() const;

    // All paint definitions must be destroyed before the vm is destroyed, because otherwise they will point to freed memory.
    struct PaintDefinition : public CanMakeWeakPtr<PaintDefinition> {
        WTF_MAKE_STRUCT_FAST_ALLOCATED;
        PaintDefinition(const AtomString& name, JSC::JSObject* paintConstructor, Ref<CSSPaintCallback>&&, Vector<AtomString>&& inputProperties, Vector<String>&& inputArguments);

        const AtomString name;
        const JSC::JSObject* const paintConstructor;
        const Ref<CSSPaintCallback> paintCallback;
        const Vector<AtomString> inputProperties;
        const Vector<String> inputArguments;
    };

    HashMap<String, std::unique_ptr<PaintDefinition>>& paintDefinitionMap() WTF_REQUIRES_LOCK(m_paintDefinitionLock);
    Lock& paintDefinitionLock() WTF_RETURNS_LOCK(m_paintDefinitionLock) { return m_paintDefinitionLock; }

    void prepareForDestruction() final
    {
        if (m_hasPreparedForDestruction)
            return;
        m_hasPreparedForDestruction = true;

        {
            Locker locker { paintDefinitionLock() };
            paintDefinitionMap().clear();
        }
        WorkletGlobalScope::prepareForDestruction();
    }

    FetchOptions::Destination destination() const final { return FetchOptions::Destination::Paintworklet; }

private:
    PaintWorkletGlobalScope(Document&, Ref<JSC::VM>&&, ScriptSourceCode&&);

    ~PaintWorkletGlobalScope()
    {
#if ASSERT_ENABLED
        Locker locker { paintDefinitionLock() };
        ASSERT(paintDefinitionMap().isEmpty());
#endif
    }

    bool isPaintWorkletGlobalScope() const final { return true; }

    HashMap<String, std::unique_ptr<PaintDefinition>> m_paintDefinitionMap WTF_GUARDED_BY_LOCK(m_paintDefinitionLock);
    Lock m_paintDefinitionLock;
    bool m_hasPreparedForDestruction { false };
};

inline auto PaintWorkletGlobalScope::paintDefinitionMap() -> HashMap<String, std::unique_ptr<PaintDefinition>>&
{
    ASSERT(m_paintDefinitionLock.isLocked());
    return m_paintDefinitionMap;
}

} // namespace WebCore

SPECIALIZE_TYPE_TRAITS_BEGIN(WebCore::PaintWorkletGlobalScope)
static bool isType(const WebCore::ScriptExecutionContext& context) { return is<WebCore::WorkletGlobalScope>(context) && downcast<WebCore::WorkletGlobalScope>(context).isPaintWorkletGlobalScope(); }
static bool isType(const WebCore::WorkletGlobalScope& context) { return context.isPaintWorkletGlobalScope(); }
SPECIALIZE_TYPE_TRAITS_END()

#endif // ENABLE(CSS_PAINTING_API)