From 4572d9671488d5d0d97d179462bd4b99a39a0a29 Mon Sep 17 00:00:00 2001 From: Marc Mutz Date: Sun, 21 Jul 2019 18:34:48 +0300 Subject: [PATCH] QWaylandCursor: replace a static QMap with a C array MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The content of the QMultiMap cursorNameMaps is static, so using a dynamic container is overkill. Replace the map by a (sorted) C array of struct {Key, Value}, and use std::equal_range to find matching cursors. This also avoids the creation of a QList on each call (due to the use of QMap:values() instead of QMap::equal_range), as well as the creation of QByteArrays, which the underlying wayland C API doesn't know about, anyway. The entries were already sorted, so the initializer_list stays the same. Add an assert that the list is ordered. Since this is library code, don't use the attractive struct { WaylandCursor, const char *name }, as that causes relocations that delay the loading of the shared object, and make sharing of the data between processes impossible. This wastes some memory, due to all the NUL padding up to the common maximum, and the next alignment step, but can be optimized later when someone writes a C++-only version of Q_STRINGTABLE. Even so, this saves 10.5KiB in text size on optimized AMD64 Linux GCC 9.1 builds. Change-Id: I19fa1742e2fcaf9de74af1e5908e796b0588d507 Reviewed-by: Mårten Nordheim --- .../platforms/wayland/qwaylandcursor.cpp | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/src/plugins/platforms/wayland/qwaylandcursor.cpp b/src/plugins/platforms/wayland/qwaylandcursor.cpp index 165df776295..4356b23a0a8 100644 --- a/src/plugins/platforms/wayland/qwaylandcursor.cpp +++ b/src/plugins/platforms/wayland/qwaylandcursor.cpp @@ -48,6 +48,8 @@ #include +#include + QT_BEGIN_NAMESPACE namespace QtWaylandClient { @@ -75,7 +77,10 @@ wl_cursor *QWaylandCursorTheme::requestCursor(WaylandCursor shape) if (struct wl_cursor *cursor = m_cursors.value(shape, nullptr)) return cursor; - static const QMultiMapcursorNamesMap { + static Q_CONSTEXPR struct ShapeAndName { + WaylandCursor shape; + const char name[33]; + } cursorNamesMap[] = { {ArrowCursor, "left_ptr"}, {ArrowCursor, "default"}, {ArrowCursor, "top_left_arrow"}, @@ -193,9 +198,14 @@ wl_cursor *QWaylandCursorTheme::requestCursor(WaylandCursor shape) {ResizeSouthWestCursor, "bottom_left_corner"}, }; - QList cursorNames = cursorNamesMap.values(shape); - for (auto &name : qAsConst(cursorNames)) { - if (wl_cursor *cursor = wl_cursor_theme_get_cursor(m_theme, name.constData())) { + const auto byShape = [](ShapeAndName lhs, ShapeAndName rhs) { + return lhs.shape < rhs.shape; + }; + Q_ASSERT(std::is_sorted(std::begin(cursorNamesMap), std::end(cursorNamesMap), byShape)); + const auto p = std::equal_range(std::begin(cursorNamesMap), std::end(cursorNamesMap), + ShapeAndName{shape, ""}, byShape); + for (auto it = p.first; it != p.second; ++it) { + if (wl_cursor *cursor = wl_cursor_theme_get_cursor(m_theme, it->name)) { m_cursors.insert(shape, cursor); return cursor; }