LSSTApplications  20.0.0
LSSTDataManagementBasePackage
PolymorphicValue.cc
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1 // -*- LSST-C++ -*-
2 /*
3  * This file is part of afw.
4  *
5  * Developed for the LSST Data Management System.
6  * This product includes software developed by the LSST Project
7  * (https://www.lsst.org).
8  * See the COPYRIGHT file at the top-level directory of this distribution
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23  */
24 
25 #include "lsst/pex/exceptions.h"
26 
28 
29 namespace lsst {
30 namespace afw {
31 namespace typehandling {
32 
33 PolymorphicValue::PolymorphicValue(Storable const& value) : _value(value.cloneStorable()) {}
34 // No move-constructor, because putting a pointer to Storable&& into a
35 // shared_ptr is safe only if the object was dynamically allocated
36 
37 PolymorphicValue::~PolymorphicValue() noexcept = default;
38 
40  : _value(other._value ? other._value->cloneStorable() : nullptr) {}
41 PolymorphicValue::PolymorphicValue(PolymorphicValue&&) noexcept = default; // other._value emptied
42 
44  if (other._value) {
45  _value = other._value->cloneStorable();
46  } else {
47  _value.reset();
48  }
49  return *this;
50 }
52  using std::swap;
53  swap(_value, other._value);
54  return *this;
55 }
56 
58  using std::swap;
59  swap(_value, other._value);
60 }
61 
62 bool PolymorphicValue::empty() const noexcept { return !_value; }
63 
64 PolymorphicValue::operator Storable&() { return get(); }
65 PolymorphicValue::operator Storable const&() const { return get(); }
67  // Both casts are safe; see Effective C++, Item 3
68  return const_cast<Storable&>(static_cast<PolymorphicValue const&>(*this).get());
69 }
71  if (_value) {
72  return *_value;
73  } else {
74  throw LSST_EXCEPT(pex::exceptions::LogicError, "Dereferenced empty PolymorphicValue.");
75  }
76 }
77 
79  if (!empty() && !other.empty()) {
80  return get().equals(other.get());
81  } else {
82  // At least one pointer is null; pointer comparison has desired behavior
83  return _value == other._value;
84  }
85 }
86 
88 
89 } // namespace typehandling
90 } // namespace afw
91 } // namespace lsst
PolymorphicValue.h
lsst::afw
Definition: imageAlgorithm.dox:1
lsst::afw::typehandling::PolymorphicValue::empty
bool empty() const noexcept
Check whether this object contains a Storable.
Definition: PolymorphicValue.cc:62
lsst::afw::typehandling::Storable
Interface supporting iteration over heterogenous containers.
Definition: Storable.h:58
lsst::afw::typehandling::PolymorphicValue::swap
void swap(PolymorphicValue &other) noexcept
Exchange the contents of this container and another.
Definition: PolymorphicValue.cc:57
lsst::afw::typehandling::PolymorphicValue::PolymorphicValue
PolymorphicValue(Storable const &value)
Create a new object containing a copy of a Storable.
Definition: PolymorphicValue.cc:33
lsst::afw::typehandling::PolymorphicValue::operator==
bool operator==(PolymorphicValue const &other) const noexcept
Test whether the contained Storables are equal.
Definition: PolymorphicValue.cc:78
lsst::afw::typehandling::PolymorphicValue::~PolymorphicValue
~PolymorphicValue() noexcept
other
ItemVariant const * other
Definition: Schema.cc:56
lsst::pex::exceptions::LogicError
Reports errors in the logical structure of the program.
Definition: Runtime.h:46
lsst::afw::typehandling::PolymorphicValue::operator=
PolymorphicValue & operator=(PolymorphicValue const &other)
Try to assign a PolymorphicValue.
Definition: PolymorphicValue.cc:43
lsst::afw::typehandling::swap
void swap(PolymorphicValue &lhs, PolymorphicValue &rhs) noexcept
Swap specialization for PolymorphicValue.
Definition: PolymorphicValue.h:152
lsst::afw::typehandling::PolymorphicValue
Container that passes Storable objects by value while preserving type.
Definition: PolymorphicValue.h:52
lsst
A base class for image defects.
Definition: imageAlgorithm.dox:1
LSST_EXCEPT
#define LSST_EXCEPT(type,...)
Create an exception with a given type.
Definition: Exception.h:48
std::swap
T swap(T... args)
lsst::afw::typehandling::PolymorphicValue::get
Storable & get()
Return a reference to the internal Storable, if one exists.
Definition: PolymorphicValue.cc:66
lsst::afw::typehandling::PolymorphicValue::hash_value
std::size_t hash_value() const
Return a hash of this object (optional operation).
Definition: PolymorphicValue.cc:87
std::size_t
exceptions.h
std::hash