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Tools/Win64/VTK/include/vtk-9.0/vtkCompositeDataSetNodeRefe...

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/*=========================================================================
Program: Visualization Toolkit
Module: vtkCompositeDataSetNodeReference.h
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
#ifndef vtkCompositeDataSetNodeReference_h
#define vtkCompositeDataSetNodeReference_h
#include "vtkCompositeDataIterator.h"
#include "vtkCompositeDataSet.h"
#include "vtkWeakPointer.h"
#include <cassert>
#include <type_traits>
#ifndef __VTK_WRAP__
namespace vtk
{
namespace detail
{
//------------------------------------------------------------------------------
// MTimeWatcher:
// operator() return true if the MTime of its argument is less than or equal
// to the MTime of the object used to construct it.
//
// Create/reset using `mtime_watcher = MTimeWatcher{obj};`
//
// Test using `bool cacheIsValid = mtime_watcher(obj);`
//
// There are two variants of this:
// - MTimeWatcher can be used to ALWAYS check for valid mtimes.
// - DebugMTimeWatcher can be used to check mtimes ONLY in debugging builds,
// and is defined as an empty, transparent no-op object in optimized builds.
// The optimized version will always return true from operator().
struct MTimeWatcher
{
vtkMTimeType MTime{ 0 };
MTimeWatcher() {}
explicit MTimeWatcher(vtkObject* o)
: MTime{ o->GetMTime() }
{
}
bool operator()(vtkObject* o) const { return o->GetMTime() <= this->MTime; }
void Reset(vtkObject* o) { this->MTime = o->GetMTime(); }
bool MTimeIsValid(vtkObject* o) const { return o->GetMTime() <= this->MTime; }
};
// empty, transparent, does nothing. operator() always returns true.
struct NoOpMTimeWatcher
{
NoOpMTimeWatcher() {}
explicit NoOpMTimeWatcher(vtkObject*) {}
bool operator()(vtkObject*) const { return true; }
void Reset(vtkObject*) {}
bool MTimeIsValid(vtkObject*) const { return true; }
};
// Debug-dependent version:
#ifndef _NDEBUG
using DebugMTimeWatcher = MTimeWatcher;
#else
using DebugMTimeWatcher = NoOpMTimeWatcher;
#endif
//------------------------------------------------------------------------------
// DebugWeakPointer: Defined to vtkWeakPointer on debugging builds, T* on
// non-debugging builds.
#ifndef _NDEBUG
template <class ObjectType>
using DebugWeakPointer = vtkWeakPointer<ObjectType>;
#else
template <class ObjectType>
using DebugWeakPointer = ObjectType*;
#endif
} // end namespace detail
/**
* A reference proxy into a vtkCompositeDataSet, obtained by dereferencing an
* iterator from the vtk::Range(vtkCompositeDataSet*) overloads.
*
* This proxy may be used as a pointer, in which case it will forward the
* currently pointed-to vtkDataObject*. This means that the following code is
* legal:
*
* ```cpp
* for (auto node : vtk::Range(cds))
* { // decltype(node) == CompositeDataSetNodeReference
* if (node) // same as: if (node.GetDataObject() != nullptr)
* {
* assert(node->IsA("vtkDataObject")); // node.GetDataObject()->IsA(...)
* node = nullptr; // node.SetDataObject(nullptr)
* }
* }
*
* for (vtkDataObject *dObj : vtk::Range(cds))
* {
* // Work with dObj
* }
* ```
*
* This allows for simple access to the objects in the composite dataset. If
* more advanced operations are required, the CompositeDataSetNodeReference can:
*
* - Access the current vtkDataObject*:
* - `vtkDataObject* NodeReference::GetDataObject() const`
* - `NodeReference::operator vtkDataObject* () const` (implicit conversion)
* - `vtkDataObject* NodeReference::operator->() const` (arrow operator)
* - Replace the current vtkDataObject* in the composite dataset:
* - `void NodeReference::SetDataObject(vtkDataObject*)`
* - `NodeReference& NodeReference::operator=(vtkDataObject*)` (assignment)
* - SetGet the vtkDataObject at the same position in another composite dataset
* - `void NodeReference::SetDataObject(vtkCompositeDataSet*, vtkDataObject*)`
* - `vtkDataObject* NodeReference::GetDataObject(vtkCompositeDataSet*) const`
* - Check and access node metadata (if any):
* - `bool NodeReference::HasMetaData() const`
* - `vtkInformation* NodeReference::GetMetaData() const`
* - Get the current flat index within the parent range:
* - `unsigned int NodeReference::GetFlatIndex() const`
*
* Assigning one reference to another assigns the vtkDataObject* pointer to the
* target reference. Assigning to non-leaf nodes invalidates all iterators /
* references.
*
* Equality testing compares each reference's DataObject and FlatIndex.
*
* @warning The NodeReference shares state with the OwnerType iterator that
* generates it. Incrementing or destroying the parent iterator will invalidate
* the reference. In debugging builds, these misuses will be caught via runtime
* assertions.
*/
template <typename IteratorType,
typename OwnerType>
class CompositeDataSetNodeReference
: private detail::DebugMTimeWatcher // empty-base optimization when NDEBUG
{
static_assert(std::is_base_of<vtkCompositeDataIterator, IteratorType>::value,
"CompositeDataSetNodeReference's IteratorType must be a "
"subclass of vtkCompositeDataIterator.");
// Either a vtkWeakPointer (debug builds) or raw pointer (non-debug builds)
mutable detail::DebugWeakPointer<IteratorType> Iterator{ nullptr };
// Check that the reference has not been invalidated by having the
// borrowed internal iterator modified.
void AssertValid() const
{
// Test that the weak pointer hasn't been cleared
assert(
"Invalid CompositeDataNodeReference accessed (iterator freed)." && this->Iterator != nullptr);
// Check MTime:
assert("Invalid CompositeDataNodeReference accessed (iterator modified)." &&
this->MTimeIsValid(this->Iterator));
}
protected:
explicit CompositeDataSetNodeReference(IteratorType* iterator)
: detail::DebugMTimeWatcher(iterator)
, Iterator(iterator)
{
}
public:
friend OwnerType; // To allow access to protected methods/base class
CompositeDataSetNodeReference() = delete;
CompositeDataSetNodeReference(const CompositeDataSetNodeReference& src) = default;
CompositeDataSetNodeReference(CompositeDataSetNodeReference&&) noexcept = default;
~CompositeDataSetNodeReference() = default;
// Assigns the DataObject from src to this:
CompositeDataSetNodeReference& operator=(const CompositeDataSetNodeReference& src)
{
this->SetDataObject(src.GetDataObject());
return *this;
}
// Compares data object and flat index:
friend bool operator==(
const CompositeDataSetNodeReference& lhs, const CompositeDataSetNodeReference& rhs)
{
return lhs.GetDataObject() == rhs.GetDataObject() && lhs.GetFlatIndex() == rhs.GetFlatIndex();
}
// Compares data object and flat index:
friend bool operator!=(
const CompositeDataSetNodeReference& lhs, const CompositeDataSetNodeReference& rhs)
{
return lhs != rhs;
}
vtkDataObject* GetDataObject() const
{
this->AssertValid();
// GetCurrentDataObject is buggy -- the iterator caches the current dataset
// internally, so if the object has changed since the iterator was
// incremented, the changes will not be visible through the iterator's
// API. See VTK issue #17529.
// Instead, look it up in the dataset. It's a bit slower, but will always be
// correct.
// return this->Iterator->GetCurrentDataObject();
return this->Iterator->GetDataSet()->GetDataSet(this->Iterator);
}
vtkDataObject* GetDataObject(vtkCompositeDataSet* other)
{
this->AssertValid();
return other->GetDataSet(this->Iterator);
}
operator bool() const { return this->GetDataObject() != nullptr; }
operator vtkDataObject*() const { return this->GetDataObject(); }
vtkDataObject* operator->() const { return this->GetDataObject(); }
void SetDataObject(vtkDataObject* obj)
{
this->AssertValid();
vtkCompositeDataSet* cds = this->Iterator->GetDataSet();
cds->SetDataSet(this->Iterator, obj);
}
void SetDataObject(vtkCompositeDataSet* other, vtkDataObject* dObj)
{
this->AssertValid();
other->SetDataSet(this->Iterator, dObj);
}
CompositeDataSetNodeReference& operator=(vtkDataObject* obj)
{
this->SetDataObject(obj);
return *this;
}
unsigned int GetFlatIndex() const
{
this->AssertValid();
return this->Iterator->GetCurrentFlatIndex();
}
bool HasMetaData() const
{
this->AssertValid();
return this->Iterator->HasCurrentMetaData() != 0;
}
vtkInformation* GetMetaData() const
{
this->AssertValid();
return this->Iterator->GetCurrentMetaData();
}
};
} // end namespace vtk
#endif // __VTK_WRAP__
#endif // vtkCompositeDataSetNodeReference_h
// VTK-HeaderTest-Exclude: vtkCompositeDataSetNodeReference.h