From 25351dcc549f1daddf5e2ae8a242191174342a3e Mon Sep 17 00:00:00 2001 From: Giuseppe D'Angelo Date: Sun, 19 Apr 2020 19:56:18 +0200 Subject: Long live QKeyCombination! C++20 via P1120 is deprecating arithmetic operations between unrelated enumeration types, and GCC 10 is already complaining. Hence, these operations might become illegal in C++23 or C++26 at the latest. A case of this that affects Qt is in key combinations: a QKeySequence can be constructed by summing / ORing modifiers and a key, for instance: Qt::CTRL + Qt::Key_A Qt::SHIFT | Qt::CTRL | Qt::Key_G (recommended, see below) The problem is that the modifiers and the key belong to different enumerations (and there's 2 enumerations for the modifier, and one for the key). To solve this: add a dedicated class to represent a combination of keys, and operators between those enumerations to build instances of this class. I would've simply defined operator|, but again docs and pre-existing code use operator+ as well, so added both to at least tackle simple cases (modifier + key). Multiple modifiers create a problem: operator+ between them yields int, not the corresponding flags type (because operator+ is not overloaded for this use case): Qt::CTRL + Qt::SHIFT + Qt::Key_A \__________________/ / int / \______________/ int Not only this loses track of the datatypes involved, but it would also then "add" the key (with NO warnings, now its int + enum, so it's not mixing enums!) and yielding int again. I don't want to special-case this; the point of the class is that int is the wrong datatype. Everything works just fine when using operator| instead: Qt::CTRL | Qt::SHIFT | Qt::Key_A \__________________/ / Qt::Modifiers / \______________/ QKeyCombination So I'm defining operator+ so that the simple cases still work, but also deprecating it. Port some code around Qt to the new class. In certain cases, it's a huge win for clarity. In some others, I've just added the necessary casts to make it still compile without warnings, without attempting refactorings. [ChangeLog][QtCore][QKeyCombination] New class to represent a combination of a key and zero or more modifiers, to be used when defining shortcuts or similar. [ChangeLog][Potentially Source-Incompatible Changes] A keyboard modifier (such as Qt::CTRL, Qt::AltModifier, etc.) should be combined with a key (such as Qt::Key_A, Qt::Key_F1, etc.) by using operator|, not operator+. The result is now an object of type QKeyCombination, that stores the key and the modifiers. Change-Id: I657a3a328232f059023fff69c5031ee31cc91dd6 Reviewed-by: Volker Hilsheimer --- src/gui/doc/snippets/code/src_gui_kernel_qkeysequence.cpp | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'src/gui/doc/snippets/code/src_gui_kernel_qkeysequence.cpp') diff --git a/src/gui/doc/snippets/code/src_gui_kernel_qkeysequence.cpp b/src/gui/doc/snippets/code/src_gui_kernel_qkeysequence.cpp index 2994bb60cf..4be214ad64 100644 --- a/src/gui/doc/snippets/code/src_gui_kernel_qkeysequence.cpp +++ b/src/gui/doc/snippets/code/src_gui_kernel_qkeysequence.cpp @@ -62,13 +62,15 @@ struct Wrapper : public QWidget QKeySequence(QKeySequence::Print); QKeySequence(tr("Ctrl+P")); QKeySequence(tr("Ctrl+p")); -QKeySequence(Qt::CTRL + Qt::Key_P); +QKeySequence(Qt::CTRL | Qt::Key_P); +QKeySequence(Qt::CTRL + Qt::Key_P); // deprecated //! [0] //! [1] QKeySequence(tr("Ctrl+X, Ctrl+C")); -QKeySequence(Qt::CTRL + Qt::Key_X, Qt::CTRL + Qt::Key_C); +QKeySequence(Qt::CTRL | Qt::Key_X, Qt::CTRL | Qt::Key_C); +QKeySequence(Qt::CTRL + Qt::Key_X, Qt::CTRL + Qt::Key_C); // deprecated //! [1] */ // Wrap non-compilable code snippet -- cgit v1.2.3