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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_VIEWS_VIEW_MODEL_H_
#define UI_VIEWS_VIEW_MODEL_H_
#include <optional>
#include <vector>
#include "base/check_op.h"
#include "base/memory/raw_ptr.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/views/views_export.h"
namespace views {
class View;
class ViewModelUtils;
// Internal implementation of the templated ViewModelT class. Provides
// non-templated "unsafe" methods for ViewModelT to wrap around. Any methods
// that allow insertion of or access to a View* should be protected, and have a
// public method in the ViewModelT subclass that provides type-safe access to
// the correct View subclass.
class VIEWS_EXPORT ViewModelBase {
public:
struct Entry {
Entry() = default;
raw_ptr<View, DanglingUntriaged> view = nullptr;
gfx::Rect ideal_bounds;
};
using Entries = std::vector<Entry>;
ViewModelBase(const ViewModelBase&) = delete;
ViewModelBase& operator=(const ViewModelBase&) = delete;
~ViewModelBase();
const Entries& entries() const { return entries_; }
// Removes the view at the specified index. This does not actually remove the
// view from the view hierarchy.
void Remove(size_t index);
// Moves the view at |index| to |target_index|. |target_index| is in terms
// of the model *after* the view at |index| is removed.
void Move(size_t index, size_t target_index);
// Variant of Move() that leaves the bounds as is. That is, after invoking
// this the bounds of the view at |target_index| (and all other indices) are
// exactly the same as the bounds of the view at |target_index| before
// invoking this.
void MoveViewOnly(size_t index, size_t target_index);
// Returns the number of views.
size_t view_size() const { return entries_.size(); }
// Removes and deletes all the views.
void Clear();
void set_ideal_bounds(size_t index, const gfx::Rect& bounds) {
check_index(index);
entries_[index].ideal_bounds = bounds;
}
const gfx::Rect& ideal_bounds(size_t index) const {
check_index(index);
return entries_[index].ideal_bounds;
}
// Returns the index of the specified view, or nullopt if the view isn't in
// the model.
std::optional<size_t> GetIndexOfView(const View* view) const;
protected:
ViewModelBase();
// Returns the view at the specified index. Note: Most users should use
// view_at() in the subclass, to get a view of the correct type. (Do not call
// ViewAtBase then static_cast to the desired type.)
View* ViewAtBase(size_t index) const {
check_index(index);
return entries_[index].view;
}
// Adds |view| to this model. This does not add |view| to a view hierarchy,
// only to this model.
void AddUnsafe(View* view, size_t index);
private:
// For access to ViewAtBase().
friend class ViewModelUtils;
void check_index(size_t index) const { DCHECK_LT(index, entries_.size()); }
Entries entries_;
};
// ViewModelT is used to track an 'interesting' set of a views. Often times
// during animations views are removed after a delay, which makes for tricky
// coordinate conversion as you have to account for the possibility of the
// indices from the model not lining up with those you expect. This class lets
// you define the 'interesting' views and operate on those views.
template <class T>
class ViewModelT : public ViewModelBase {
public:
ViewModelT() = default;
ViewModelT(const ViewModelT&) = delete;
ViewModelT& operator=(const ViewModelT&) = delete;
// Adds |view| to this model. This does not add |view| to a view hierarchy,
// only to this model.
void Add(T* view, size_t index) { AddUnsafe(view, index); }
// Returns the view at the specified index.
T* view_at(size_t index) const { return static_cast<T*>(ViewAtBase(index)); }
};
// ViewModel is a collection of views with no specfic type. If all views have
// the same type, the use of ViewModelT is preferred so that the views can be
// retrieved without potentially unsafe downcasts.
using ViewModel = ViewModelT<View>;
} // namespace views
#endif // UI_VIEWS_VIEW_MODEL_H_
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