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optional exception check, primarily adding noexcept to signatures

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-- also reordered the assignments in set/clear to ensure "has_value_" doesn't change if the assignment operator of T throws
This commit is contained in:
Crzyrndm 2018-07-10 17:22:54 +12:00
parent ad69e7bf11
commit 34e8f274de
1 changed files with 16 additions and 14 deletions
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30
include/xlnt/utils/optional.hpp
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@ -40,14 +40,17 @@ public:
/// <summary> /// <summary>
/// Default contructor. is_set() will be false initially. /// Default contructor. is_set() will be false initially.
/// </summary> /// </summary>
optional() : has_value_(false), value_(T()) optional() noexcept(std::is_nothrow_default_constructible<T>{})
: has_value_(false), value_(T())
{ {
} }
/// <summary> /// <summary>
/// Constructs this optional with a value. /// Constructs this optional with a value.
/// noexcept if T copy ctor is noexcept
/// </summary> /// </summary>
optional(const T &value) : has_value_(true), value_(value) optional(const T &value) noexcept(std::is_nothrow_copy_constructible<T>{})
: has_value_(true), value_(value)
{ {
} }
@ -55,7 +58,7 @@ public:
/// Returns true if this object currently has a value set. This should /// Returns true if this object currently has a value set. This should
/// be called before accessing the value with optional::get(). /// be called before accessing the value with optional::get().
/// </summary> /// </summary>
bool is_set() const bool is_set() const noexcept
{ {
return has_value_; return has_value_;
} }
@ -63,10 +66,10 @@ public:
/// <summary> /// <summary>
/// Sets the value to value. /// Sets the value to value.
/// </summary> /// </summary>
void set(const T &value) void set(const T &value) noexcept(std::is_nothrow_assignable<T, T>{})
{ {
has_value_ = true;
value_ = value; value_ = value;
has_value_ = true;
} }
/// <summary> /// <summary>
@ -101,20 +104,18 @@ public:
/// Resets the internal value using its default constructor. After this is /// Resets the internal value using its default constructor. After this is
/// called, is_set() will return false until a new value is provided. /// called, is_set() will return false until a new value is provided.
/// </summary> /// </summary>
void clear() void clear() noexcept(std::is_nothrow_assignable<T, T>{} && std::is_nothrow_default_constructible<T>{})
{ {
has_value_ = false;
value_ = T(); value_ = T();
has_value_ = false;
} }
/// <summary> /// <summary>
/// Assignment operator. Equivalent to setting the value using optional::set. /// Assignment operator. Equivalent to setting the value using optional::set.
/// </summary> /// </summary>
optional &operator=(const T &rhs) optional &operator=(const T &rhs) noexcept(noexcept(set(std::declval<T &>())))
{ {
has_value_ = true; set(rhs);
value_ = rhs;
return *this; return *this;
} }
@ -123,9 +124,10 @@ public:
/// or both have a value and those values are equal according to /// or both have a value and those values are equal according to
/// their equality operator. /// their equality operator.
/// </summary> /// </summary>
bool operator==(const optional<T> &other) const bool operator==(const optional<T> &other) const noexcept
{ {
if (has_value_ != other.has_value_) { if (has_value_ != other.has_value_)
{
return false; return false;
} }
if (!has_value_) if (!has_value_)
@ -140,7 +142,7 @@ public:
/// or both have a value and those values are equal according to /// or both have a value and those values are equal according to
/// their equality operator. /// their equality operator.
/// </summary> /// </summary>
bool operator!=(const optional<T> &other) const bool operator!=(const optional<T> &other) const noexcept
{ {
return !operator==(other); return !operator==(other);
} }