third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.h

// 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 CSSPaintDefinition_h
#define CSSPaintDefinition_h

#include "bindings/core/v8/ScopedPersistent.h"
#include "core/CSSPropertyNames.h"
#include "core/css/CSSSyntaxDescriptor.h"
#include "platform/geometry/IntSize.h"
#include "platform/heap/Handle.h"
#include <v8.h>

namespace blink {

class Image;
class LayoutObject;
class ScriptState;

// Represents a javascript class registered on the PaintWorkletGlobalScope by
// the author. It will store the properties for invalidation and input argument
// types as well.
class CSSPaintDefinition final
    : public GarbageCollectedFinalized<CSSPaintDefinition> {
 public:
  static CSSPaintDefinition* create(
      ScriptState*,
      v8::Local<v8::Function> constructor,
      v8::Local<v8::Function> paint,
      Vector<CSSPropertyID>&,
      Vector<AtomicString>& customInvalidationProperties,
      Vector<CSSSyntaxDescriptor>& inputArgumentTypes,
      bool hasAlpha);
  virtual ~CSSPaintDefinition();

  // Invokes the javascript 'paint' callback on an instance of the javascript
  // class. The size given will be the size of the PaintRenderingContext2D
  // given to the callback.
  //
  // This may return a nullptr (representing an invalid image) if javascript
  // throws an error.
  PassRefPtr<Image> paint(const LayoutObject&, const IntSize&, float zoom);
  const Vector<CSSPropertyID>& nativeInvalidationProperties() const {
    return m_nativeInvalidationProperties;
  }
  const Vector<AtomicString>& customInvalidationProperties() const {
    return m_customInvalidationProperties;
  }
  const Vector<CSSSyntaxDescriptor>& inputArgumentTypes() const {
    return m_inputArgumentTypes;
  }
  bool hasAlpha() const { return m_hasAlpha; }

  ScriptState* getScriptState() const { return m_scriptState.get(); }

  v8::Local<v8::Function> paintFunctionForTesting(v8::Isolate* isolate) {
    return m_paint.newLocal(isolate);
  }

  DEFINE_INLINE_TRACE(){};

 private:
  CSSPaintDefinition(ScriptState*,
                     v8::Local<v8::Function> constructor,
                     v8::Local<v8::Function> paint,
                     Vector<CSSPropertyID>& nativeInvalidationProperties,
                     Vector<AtomicString>& customInvalidationProperties,
                     Vector<CSSSyntaxDescriptor>& inputArgumentTypes,
                     bool hasAlpha);

  void maybeCreatePaintInstance();

  RefPtr<ScriptState> m_scriptState;

  // This object keeps the class instance object, constructor function and
  // paint function alive. This object needs to be destroyed to break a
  // reference cycle between it and the PaintWorkletGlobalScope.
  ScopedPersistent<v8::Function> m_constructor;
  ScopedPersistent<v8::Function> m_paint;

  // At the moment there is only ever one instance of a paint class per type.
  ScopedPersistent<v8::Object> m_instance;

  bool m_didCallConstructor;

  Vector<CSSPropertyID> m_nativeInvalidationProperties;
  Vector<AtomicString> m_customInvalidationProperties;
  // Input argument types, if applicable.
  Vector<CSSSyntaxDescriptor> m_inputArgumentTypes;
  bool m_hasAlpha;
};

}  // namespace blink

#endif  // CSSPaintDefinition_h