RmlUi/Source/Core/DataView.h

/*
 * This source file is part of RmlUi, the HTML/CSS Interface Middleware
 *
 * For the latest information, see http://github.com/mikke89/RmlUi
 *
 * Copyright (c) 2008-2010 CodePoint Ltd, Shift Technology Ltd
 * Copyright (c) 2019 The RmlUi Team, and contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

#ifndef RMLUI_CORE_DATAVIEW_H
#define RMLUI_CORE_DATAVIEW_H

#include "../../Include/RmlUi/Core/Header.h"
#include "../../Include/RmlUi/Core/Types.h"
#include "../../Include/RmlUi/Core/Traits.h"
#include "../../Include/RmlUi/Core/DataTypes.h"

namespace Rml {

class Element;
class DataModel;


class DataViewInstancer : public NonCopyMoveable {
public:
	DataViewInstancer() {}
	virtual ~DataViewInstancer() {}
	virtual DataViewPtr InstanceView(Element* element) = 0;
};

template<typename T>
class DataViewInstancerDefault final : public DataViewInstancer {
public:
	DataViewPtr InstanceView(Element* element) override {
		return DataViewPtr(new T(element));
	}
};

/**
	Data view.

	Data views are used to present a data variable in the document by different means.
	A data view is declared in the document by the element attribute:
	
	    data-[type]-[modifier]="[expression]"

	The modifier may or may not be required depending on the data view.
 */

class DataView : public Releasable {
public:
	virtual ~DataView();

	// Initialize the data view.
	// @param[in] model The data model the view will be attached to.
	// @param[in] element The element which spawned the view.
	// @param[in] expression The value of the element's 'data-' attribute which spawned the view (see above).
	// @param[in] modifier_or_inner_rml The modifier for the given view type (see above), or the inner rml contents for structural data views.
	// @return True on success.
	virtual bool Initialize(DataModel& model, Element* element, const String& expression, const String& modifier_or_inner_rml) = 0;

	// Update the data view.
	// Returns true if the update resulted in a document change.
	virtual bool Update(DataModel& model) = 0;

	// Returns the list of data variable name(s) which can modify this view.
	virtual StringList GetVariableNameList() const = 0;

	// Returns the attached element if it still exists.
	Element* GetElement() const;

	// Data views are first sorted by the depth of the attached element in the
	// document tree, then optionally by an offset specified for each data view.
	int GetSortOrder() const;
	
	// Returns true if the element still exists.
	bool IsValid() const;
	
protected:
	// @param[in] element The element this data view is attached to.
	// @param[in] sort_offset A number [-1000, 999] specifying the update order of this
	//            data view at the same tree depth, negative numbers are updated first.
	DataView(Element* element, int sort_offset);

private:
	ObserverPtr<Element> attached_element;
	int sort_order;
};



class DataViews : NonCopyMoveable {
public:
	DataViews();
	~DataViews();

	void Add(DataViewPtr view);

	void OnElementRemove(Element* element);

	bool Update(DataModel& model, const DirtyVariables& dirty_variables);

private:
	using DataViewList = Vector<DataViewPtr>;

	DataViewList views;
	
	DataViewList views_to_add;
	DataViewList views_to_remove;

	using NameViewMap = UnorderedMultimap<String, DataView*>;
	NameViewMap name_view_map;
};

} // namespace Rml
#endif