From 2b50c8bec086ae975ac5152e08f6b3dcf76306a0 Mon Sep 17 00:00:00 2001 From: Marc Mutz Date: Fri, 2 Jul 2021 08:32:09 +0200 Subject: QObject: optimize the common case of findChildren(QString()) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Outside tests, all in-tree callers of QObject::findChildren() pass no name to match, and in my experience that is also true for the vast majority of out-of-tree users. Avoid the temporary QString creation in the caller and the repeated QString::isNull() checks in the implementation by overloading findChildren() without a name argument and checking for name.isNull() only once, forking off into separate helper functions. Adjust in-tree callers that used an explicit `QString()` argument in order to pass options, which goes to show that `name` should never have been the first argument of findChilden() in the first place, even though I appreciate the symmetry with findChild() (the use-cases of which, however, are radically different). Change a `findChildren().size() == 0` call found while scanning for findChildren() calls to `!findChild()` as a drive-by. Modernize loops in the various qt_qFindChild{,ren}_helper() overloads to match how the new code looks. [ChangeLog][QtCore][QObject] Added findChildren() overload taking no name (thus optimizing this common case). Change-Id: Ifc56e5438023d079b40c67f11ae274a3e128ad5e Reviewed-by: Fabian Kosmale Reviewed-by: Mårten Nordheim --- src/corelib/doc/snippets/code/src_corelib_kernel_qobject.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/corelib/doc/snippets/code') diff --git a/src/corelib/doc/snippets/code/src_corelib_kernel_qobject.cpp b/src/corelib/doc/snippets/code/src_corelib_kernel_qobject.cpp index fddda64b19..8a007899e3 100644 --- a/src/corelib/doc/snippets/code/src_corelib_kernel_qobject.cpp +++ b/src/corelib/doc/snippets/code/src_corelib_kernel_qobject.cpp @@ -449,7 +449,7 @@ QListWidget *list = parentWidget->findChild(QString(), Qt::FindDi //! [43] -QList childButtons = parentWidget.findChildren(QString(), Qt::FindDirectChildrenOnly); +QList childButtons = parentWidget.findChildren(Qt::FindDirectChildrenOnly); //! [43] //! [44] -- cgit v1.2.3