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Extract Header qforeach.h from qglobal.h
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Task-number: QTBUG-99313
Change-Id: Ie89314ca7022e88c1fea957880c5aa4a41640744
Reviewed-by: Thiago Macieira <[email protected]>
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@marcmutz
marcmutz committed Dec 30, 2021
1 parent f0ffe35 commit ffcf4f4
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Showing 3 changed files with 140 additions and 84 deletions.
135 changes: 135 additions & 0 deletions src/corelib/global/qforeach.h
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@@ -0,0 +1,135 @@
/****************************************************************************
**
** Copyright (C) 2020 The Qt Company Ltd.
** Copyright (C) 2019 Intel Corporation.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef QFOREACH_H
#define QFOREACH_H

#include <QtCore/qglobal.h>

QT_BEGIN_NAMESPACE

#if 0
#pragma qt_class(QForeach)
#pragma qt_sync_stop_processing
#endif

#ifndef QT_NO_FOREACH

namespace QtPrivate {

template <typename T>
class QForeachContainer {
Q_DISABLE_COPY(QForeachContainer)
public:
QForeachContainer(const T &t) : c(t), i(qAsConst(c).begin()), e(qAsConst(c).end()) {}
QForeachContainer(T &&t) : c(std::move(t)), i(qAsConst(c).begin()), e(qAsConst(c).end()) {}

QForeachContainer(QForeachContainer &&other)
: c(std::move(other.c)),
i(qAsConst(c).begin()),
e(qAsConst(c).end()),
control(std::move(other.control))
{
}

QForeachContainer &operator=(QForeachContainer &&other)
{
c = std::move(other.c);
i = qAsConst(c).begin();
e = qAsConst(c).end();
control = std::move(other.control);
return *this;
}

T c;
typename T::const_iterator i, e;
int control = 1;
};

// Containers that have a detach function are considered shared, and are OK in a foreach loop
template <typename T, typename = decltype(std::declval<T>().detach())>
inline void warnIfContainerIsNotShared(int) {}

#if QT_DEPRECATED_SINCE(6, 0)
// Other containers will copy themselves if used in foreach, this use is deprecated
template <typename T>
QT_DEPRECATED_VERSION_X_6_0("Do not use foreach/Q_FOREACH with containers which are not implicitly shared. "
"Prefer using a range-based for loop with these containers: `for (const auto &it : container)`, "
"keeping in mind that range-based for doesn't copy the container as Q_FOREACH does")
inline void warnIfContainerIsNotShared(...) {}
#endif

template<typename T>
QForeachContainer<typename std::decay<T>::type> qMakeForeachContainer(T &&t)
{
warnIfContainerIsNotShared<typename std::decay<T>::type>(0);
return QForeachContainer<typename std::decay<T>::type>(std::forward<T>(t));
}

}

// Use C++17 if statement with initializer. User's code ends up in a else so
// scoping of different ifs is not broken
#define Q_FOREACH_IMPL(variable, name, container) \
for (auto name = QtPrivate::qMakeForeachContainer(container); name.i != name.e; ++name.i) \
if (variable = *name.i; false) {} else

#define Q_FOREACH_JOIN(A, B) Q_FOREACH_JOIN_IMPL(A, B)
#define Q_FOREACH_JOIN_IMPL(A, B) A ## B

#define Q_FOREACH(variable, container) \
Q_FOREACH_IMPL(variable, Q_FOREACH_JOIN(_container_, __LINE__), container)
#endif // QT_NO_FOREACH

#define Q_FOREVER for(;;)
#ifndef QT_NO_KEYWORDS
# ifndef QT_NO_FOREACH
# ifndef foreach
# define foreach Q_FOREACH
# endif
# endif // QT_NO_FOREACH
# ifndef forever
# define forever Q_FOREVER
# endif
#endif

QT_END_NAMESPACE

#endif /* QFOREACH_H */
8 changes: 4 additions & 4 deletions src/corelib/global/qglobal.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3701,7 +3701,7 @@ bool qunsetenv(const char *varName)

/*!
\macro forever
\relates <QtGlobal>
\relates <QForeach>
This macro is provided for convenience for writing infinite
loops.
Expand All @@ -3722,7 +3722,7 @@ bool qunsetenv(const char *varName)

/*!
\macro Q_FOREVER
\relates <QtGlobal>
\relates <QForeach>
Same as \l{forever}.
Expand All @@ -3734,7 +3734,7 @@ bool qunsetenv(const char *varName)

/*!
\macro foreach(variable, container)
\relates <QtGlobal>
\relates <QForeach>
This macro is used to implement Qt's \c foreach loop. The \a
variable parameter is a variable name or variable definition; the
Expand All @@ -3756,7 +3756,7 @@ bool qunsetenv(const char *varName)

/*!
\macro Q_FOREACH(variable, container)
\relates <QtGlobal>
\relates <QForeach>
Same as foreach(\a variable, \a container).
Expand Down
81 changes: 1 addition & 80 deletions src/corelib/global/qglobal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1242,86 +1242,6 @@ constexpr std::underlying_type_t<Enum> qToUnderlying(Enum e) noexcept
#define Q_IMPLICIT
#endif

#ifndef QT_NO_FOREACH

namespace QtPrivate {

template <typename T>
class QForeachContainer {
Q_DISABLE_COPY(QForeachContainer)
public:
QForeachContainer(const T &t) : c(t), i(qAsConst(c).begin()), e(qAsConst(c).end()) {}
QForeachContainer(T &&t) : c(std::move(t)), i(qAsConst(c).begin()), e(qAsConst(c).end()) {}

QForeachContainer(QForeachContainer &&other)
: c(std::move(other.c)),
i(qAsConst(c).begin()),
e(qAsConst(c).end()),
control(std::move(other.control))
{
}

QForeachContainer &operator=(QForeachContainer &&other)
{
c = std::move(other.c);
i = qAsConst(c).begin();
e = qAsConst(c).end();
control = std::move(other.control);
return *this;
}

T c;
typename T::const_iterator i, e;
int control = 1;
};

// Containers that have a detach function are considered shared, and are OK in a foreach loop
template <typename T, typename = decltype(std::declval<T>().detach())>
inline void warnIfContainerIsNotShared(int) {}

#if QT_DEPRECATED_SINCE(6, 0)
// Other containers will copy themselves if used in foreach, this use is deprecated
template <typename T>
QT_DEPRECATED_VERSION_X_6_0("Do not use foreach/Q_FOREACH with containers which are not implicitly shared. "
"Prefer using a range-based for loop with these containers: `for (const auto &it : container)`, "
"keeping in mind that range-based for doesn't copy the container as Q_FOREACH does")
inline void warnIfContainerIsNotShared(...) {}
#endif

template<typename T>
QForeachContainer<typename std::decay<T>::type> qMakeForeachContainer(T &&t)
{
warnIfContainerIsNotShared<typename std::decay<T>::type>(0);
return QForeachContainer<typename std::decay<T>::type>(std::forward<T>(t));
}

}

// Use C++17 if statement with initializer. User's code ends up in a else so
// scoping of different ifs is not broken
#define Q_FOREACH_IMPL(variable, name, container) \
for (auto name = QtPrivate::qMakeForeachContainer(container); name.i != name.e; ++name.i) \
if (variable = *name.i; false) {} else

#define Q_FOREACH_JOIN(A, B) Q_FOREACH_JOIN_IMPL(A, B)
#define Q_FOREACH_JOIN_IMPL(A, B) A ## B

#define Q_FOREACH(variable, container) \
Q_FOREACH_IMPL(variable, Q_FOREACH_JOIN(_container_, __LINE__), container)
#endif // QT_NO_FOREACH

#define Q_FOREVER for(;;)
#ifndef QT_NO_KEYWORDS
# ifndef QT_NO_FOREACH
# ifndef foreach
# define foreach Q_FOREACH
# endif
# endif // QT_NO_FOREACH
# ifndef forever
# define forever Q_FOREVER
# endif
#endif

template <typename T> inline T *qGetPtrHelper(T *ptr) noexcept { return ptr; }
template <typename Ptr> inline auto qGetPtrHelper(Ptr &ptr) noexcept -> decltype(ptr.get())
{ static_assert(noexcept(ptr.get()), "Smart d pointers for Q_DECLARE_PRIVATE must have noexcept get()"); return ptr.get(); }
Expand Down Expand Up @@ -1485,6 +1405,7 @@ QT_END_NAMESPACE
#include <QtCore/qglobalstatic.h>
#include <QtCore/qnumeric.h>
#include <QtCore/qversiontagging.h>
#include <QtCore/qforeach.h>

#endif /* __cplusplus */
#endif /* !__ASSEMBLER__ */
Expand Down

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