home/src/utils.hh
2017-06-07 11:55:42 +01:00

153 lines
3.0 KiB
C++

#ifndef utils_hh_INCLUDED
#define utils_hh_INCLUDED
#include "assert.hh"
#include <memory>
namespace Kakoune
{
// *** Singleton ***
//
// Singleton helper class, every singleton type T should inherit
// from Singleton<T> to provide a consistent interface.
template<typename T>
class Singleton
{
public:
Singleton(const Singleton&) = delete;
Singleton& operator=(const Singleton&) = delete;
static T& instance()
{
kak_assert (ms_instance);
return *ms_instance;
}
static bool has_instance()
{
return ms_instance != nullptr;
}
protected:
Singleton()
{
kak_assert(not ms_instance);
ms_instance = static_cast<T*>(this);
}
~Singleton()
{
kak_assert(ms_instance == this);
ms_instance = nullptr;
}
private:
static T* ms_instance;
};
template<typename T>
T* Singleton<T>::ms_instance = nullptr;
// *** On scope end ***
//
// on_scope_end provides a way to register some code to be
// executed when current scope closes.
//
// usage:
// auto cleaner = on_scope_end([]() { ... });
//
// This permits to cleanup c-style resources without implementing
// a wrapping class
template<typename T>
class OnScopeEnd
{
public:
[[gnu::always_inline]]
OnScopeEnd(T func) : m_func(std::move(func)) {}
[[gnu::always_inline]]
~OnScopeEnd() { m_func(); }
private:
T m_func;
};
template<typename T>
OnScopeEnd<T> on_scope_end(T t)
{
return OnScopeEnd<T>{std::move(t)};
}
// bool that can be set (to true) multiple times, and will
// be false only when unset the same time;
struct NestedBool
{
void set() { m_count++; }
void unset() { kak_assert(m_count > 0); m_count--; }
operator bool() const { return m_count > 0; }
private:
int m_count = 0;
};
struct ScopedSetBool
{
ScopedSetBool(NestedBool& nested_bool, bool condition = true)
: m_nested_bool(nested_bool), m_condition(condition)
{
if (m_condition)
m_nested_bool.set();
}
~ScopedSetBool()
{
if (m_condition)
m_nested_bool.unset();
}
private:
NestedBool& m_nested_bool;
bool m_condition;
};
// *** Misc helper functions ***
template<typename T, typename... Args>
std::unique_ptr<T> make_unique(Args&&... args)
{
return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
}
template<typename T>
bool operator== (const std::unique_ptr<T>& lhs, T* rhs)
{
return lhs.get() == rhs;
}
template<typename T>
const T& clamp(const T& val, const T& min, const T& max)
{
return (val < min ? min : (val > max ? max : val));
}
template<typename Iterator, typename EndIterator, typename T>
bool skip_while(Iterator& it, const EndIterator& end, T condition)
{
while (it != end and condition(*it))
++it;
return it != end;
}
template<typename Iterator, typename BeginIterator, typename T>
bool skip_while_reverse(Iterator& it, const BeginIterator& begin, T condition)
{
while (it != begin and condition(*it))
--it;
return condition(*it);
}
}
#endif // utils_hh_INCLUDED