#include <quniquehandle_p.h>

Inheritance diagram for QUniqueHandle< HandleTraits >:

Collaboration diagram for QUniqueHandle< HandleTraits >:

Public Types
using	Type = typename HandleTraits::Type

Public Member Functions
	QUniqueHandle ()=default

	QUniqueHandle (const Type &handle) noexcept

	QUniqueHandle (QUniqueHandle &&other) noexcept

	~QUniqueHandle () noexcept

QUniqueHandle &	operator= (QUniqueHandle &&rhs) noexcept

	QUniqueHandle (const QUniqueHandle &)=delete

QUniqueHandle &	operator= (const QUniqueHandle &)=delete

bool	isValid () const noexcept

	operator bool () const noexcept

Type	get () const noexcept

void	reset (const Type &handle) noexcept

Type	release () noexcept

Type *	operator& () noexcept

void	close () noexcept

Friends
bool	operator== (const QUniqueHandle &lhs, const QUniqueHandle &rhs) noexcept

bool	operator!= (const QUniqueHandle &lhs, const QUniqueHandle &rhs) noexcept

bool	operator< (const QUniqueHandle &lhs, const QUniqueHandle &rhs) noexcept

bool	operator<= (const QUniqueHandle &lhs, const QUniqueHandle &rhs) noexcept

bool	operator> (const QUniqueHandle &lhs, const QUniqueHandle &rhs) noexcept

bool	operator>= (const QUniqueHandle &lhs, const QUniqueHandle &rhs) noexcept

Detailed Description

template<typename HandleTraits>
class QUniqueHandle< HandleTraits >

QUniqueHandle is a general purpose RAII wrapper intended for interfacing with resource-allocating C-style APIs, for example operating system APIs, database engine APIs, or any other scenario where resources are allocated and released, and where pointer semantics does not seem a perfect fit.

QUniqueHandle does not support copying, because it is intended to maintain ownership of resources that can not be copied. This makes it safer to use than naked handle types, since ownership is maintained by design.

The underlying handle object is described using a client supplied HandleTraits object that is implemented per resource type. The traits struct must describe two properties of a handle:

1) What value is considered invalid 2) How to close a resource.

Example 1:

struct InvalidHandleTraits {
    using Type = HANDLE;

    static Type invalidValue() {
        return INVALID_HANDLE_VALUE;
    }

    static bool close(Type handle) {
        return CloseHandle(handle) != 0;
    }
}

using FileHandle = QUniqueHandle<InvalidHandleTraits>;

Usage:

Takes ownership of returned handle. FileHandle handle{ CreateFile(...) };

if (!handle.isValid()) { qDebug() << GetLastError() return; }

...

Example 2:

struct SqLiteTraits {
    using Type = sqlite3*;

    static Type invalidValue() {
        return nullptr;
    }

    static bool close(Type handle) {
        sqlite3_close(handle);
        return true;
    }
}

using DbHandle = QUniqueHandle<SqLiteTraits>;

Usage:

DbHandle h;

Take ownership of returned handle. int result = sqlite3_open(":memory:", &h);

...

NOTE: The QUniqueHandle assumes that closing a resource is guaranteed to succeed, and provides no support for handling failure to close a resource. It is therefore only recommended for use cases where failure to close a resource is either not an error, or an unrecoverable error.

Definition at line 107 of file quniquehandle_p.h.

Member Typedef Documentation

◆ Type

template<typename HandleTraits >

using QUniqueHandle< HandleTraits >::Type = typename HandleTraits::Type

Definition at line 110 of file quniquehandle_p.h.

Constructor & Destructor Documentation

◆ QUniqueHandle() [1/4]

template<typename HandleTraits >

QUniqueHandle< HandleTraits >::QUniqueHandle ( )

default

◆ QUniqueHandle() [2/4]

template<typename HandleTraits >

QUniqueHandle< HandleTraits >::QUniqueHandle ( const Type & handle )

inlineexplicitnoexcept

Definition at line 114 of file quniquehandle_p.h.

◆ QUniqueHandle() [3/4]

template<typename HandleTraits >

QUniqueHandle< HandleTraits >::QUniqueHandle ( QUniqueHandle< HandleTraits > && other )

inlinenoexcept

Definition at line 118 of file quniquehandle_p.h.

References other().

Here is the call graph for this function:

◆ ~QUniqueHandle()

template<typename HandleTraits >

QUniqueHandle< HandleTraits >::~QUniqueHandle ( )

inlinenoexcept

Definition at line 122 of file quniquehandle_p.h.

References QUniqueHandle< HandleTraits >::close().

Here is the call graph for this function:

◆ QUniqueHandle() [4/4]

template<typename HandleTraits >

QUniqueHandle< HandleTraits >::QUniqueHandle ( const QUniqueHandle< HandleTraits > & )

delete

Member Function Documentation

◆ close()

template<typename HandleTraits >

void QUniqueHandle< HandleTraits >::close ( )

inlinenoexcept

Definition at line 176 of file quniquehandle_p.h.

References QUniqueHandle< HandleTraits >::isValid(), and Q_ASSERT.

Referenced by QUniqueHandle< HandleTraits >::~QUniqueHandle(), and QUniqueHandle< HandleTraits >::reset().

Here is the call graph for this function:

Here is the caller graph for this function:

◆ get()

template<typename HandleTraits >

Type QUniqueHandle< HandleTraits >::get ( ) const

inlinenoexcept

Definition at line 149 of file quniquehandle_p.h.

Referenced by QGstreamerVideoDevices::QGstreamerVideoDevices(), QGstreamerVideoDevices::~QGstreamerVideoDevices(), QGString::asStringView(), MFPlayerSession::close(), Scheduler::flush(), MFPlayerSession::Invoke(), QGstImpl::QSharedHandle< HandleTraits >::operator=(), QGstreamerAudioDecoder::processBusMessage(), QGstreamerMediaPlayer::processBusMessage(), QGstreamerMediaEncoder::processBusMessage(), Scheduler::scheduleSample(), Scheduler::startScheduler(), Scheduler::stopScheduler(), and QGString::toQString().

Here is the caller graph for this function:

◆ isValid()

template<typename HandleTraits >

bool QUniqueHandle< HandleTraits >::isValid ( ) const

inlinenoexcept

Definition at line 139 of file quniquehandle_p.h.

Referenced by QUniqueHandle< HandleTraits >::close(), QUniqueHandle< HandleTraits >::operator bool(), and QUniqueHandle< HandleTraits >::operator&().

Here is the caller graph for this function:

◆ operator bool()

template<typename HandleTraits >

QUniqueHandle< HandleTraits >::operator bool ( ) const

inlineexplicitnoexcept

Definition at line 144 of file quniquehandle_p.h.

References QUniqueHandle< HandleTraits >::isValid().

Here is the call graph for this function:

◆ operator&()

template<typename HandleTraits >

Type * QUniqueHandle< HandleTraits >::operator& ( )

inlinenoexcept

Definition at line 170 of file quniquehandle_p.h.

References QUniqueHandle< HandleTraits >::isValid(), and Q_ASSERT.

Here is the call graph for this function:

◆ operator=() [1/2]

template<typename HandleTraits >

QUniqueHandle & QUniqueHandle< HandleTraits >::operator= ( const QUniqueHandle< HandleTraits > & )

delete

◆ operator=() [2/2]

template<typename HandleTraits >

QUniqueHandle & QUniqueHandle< HandleTraits >::operator= ( QUniqueHandle< HandleTraits > && rhs )

inlinenoexcept

Definition at line 127 of file quniquehandle_p.h.

◆ release()

template<typename HandleTraits >

Type QUniqueHandle< HandleTraits >::release ( )

inlinenoexcept

Definition at line 163 of file quniquehandle_p.h.

◆ reset()

template<typename HandleTraits >

void QUniqueHandle< HandleTraits >::reset ( const Type & handle )

inlinenoexcept

Definition at line 154 of file quniquehandle_p.h.

References QUniqueHandle< HandleTraits >::close().

Here is the call graph for this function:

Friends And Related Symbol Documentation

◆ operator!=

template<typename HandleTraits >

bool operator!=	(	const QUniqueHandle< HandleTraits > &	lhs,
		const QUniqueHandle< HandleTraits > &	rhs )

friend

Definition at line 192 of file quniquehandle_p.h.

◆ operator<

template<typename HandleTraits >

bool operator<	(	const QUniqueHandle< HandleTraits > &	lhs,
		const QUniqueHandle< HandleTraits > &	rhs )

friend

Definition at line 197 of file quniquehandle_p.h.

◆ operator<=

template<typename HandleTraits >

bool operator<=	(	const QUniqueHandle< HandleTraits > &	lhs,
		const QUniqueHandle< HandleTraits > &	rhs )

friend

Definition at line 202 of file quniquehandle_p.h.

◆ operator==

template<typename HandleTraits >

bool operator==	(	const QUniqueHandle< HandleTraits > &	lhs,
		const QUniqueHandle< HandleTraits > &	rhs )

friend

Definition at line 187 of file quniquehandle_p.h.

◆ operator>

template<typename HandleTraits >

bool operator>	(	const QUniqueHandle< HandleTraits > &	lhs,
		const QUniqueHandle< HandleTraits > &	rhs )

friend

Definition at line 207 of file quniquehandle_p.h.

◆ operator>=

template<typename HandleTraits >

bool operator>=	(	const QUniqueHandle< HandleTraits > &	lhs,
		const QUniqueHandle< HandleTraits > &	rhs )

friend

Definition at line 212 of file quniquehandle_p.h.

The documentation for this class was generated from the following file:

qtbase/src/corelib/tools/quniquehandle_p.h (8d367dec156c1aa63544bd851809caa7e72d307e)

Public Types

Public Member Functions

Friends

Detailed Description

Member Typedef Documentation

◆ Type

Constructor & Destructor Documentation

◆ QUniqueHandle() [1/4]

◆ QUniqueHandle() [2/4]

◆ QUniqueHandle() [3/4]

◆ ~QUniqueHandle()

◆ QUniqueHandle() [4/4]

Member Function Documentation

◆ close()

◆ get()

◆ isValid()

◆ operator bool()

◆ operator&()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ release()

◆ reset()

Friends And Related Symbol Documentation

◆ operator!=

◆ operator<

◆ operator<=

◆ operator==

◆ operator>

◆ operator>=