xcb: replace inefficient uses of QList with QVector

xcb atoms are uint32s, so a QList of them wastes 50% memory on 64-bit
platforms. Other parts of the code already store xcb_atom_t's in QVector,
so use QVector everywhere (also leads to less code expansion).

Change-Id: Ib4afb35e499577a7509d04a18b830d9b31f6abd0
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

5 files changed, 12 insertions, 10 deletions

diff --git a/src/plugins/platforms/xcb/qxcbclipboard.cpp b/src/plugins/platforms/xcb/qxcbclipboard.cpp
index e7f8510706..3b30274f25 100644
--- a/src/plugins/platforms/xcb/qxcbclipboard.cpp
+++ b/src/plugins/platforms/xcb/qxcbclipboard.cpp
@@ -135,9 +135,10 @@ protected:
 
         (void)formats(); // trigger update of format list
 
-        QList<xcb_atom_t> atoms;
+        QVector<xcb_atom_t> atoms;
         xcb_atom_t *targets = (xcb_atom_t *) format_atoms.data();
         int size = format_atoms.size() / sizeof(xcb_atom_t);
+        atoms.reserve(size);
         for (int i = 0; i < size; ++i)
             atoms.append(targets[i]);
 
@@ -524,7 +525,7 @@ xcb_atom_t QXcbClipboard::sendTargetsSelection(QMimeData *d, xcb_window_t window
     QVector<xcb_atom_t> types;
     QStringList formats = QInternalMimeData::formatsHelper(d);
     for (int i = 0; i < formats.size(); ++i) {
-        QList<xcb_atom_t> atoms = QXcbMime::mimeAtomsForFormat(connection(), formats.at(i));
+        QVector<xcb_atom_t> atoms = QXcbMime::mimeAtomsForFormat(connection(), formats.at(i));
         for (int j = 0; j < atoms.size(); ++j) {
             if (!types.contains(atoms.at(j)))
                 types.append(atoms.at(j));
diff --git a/src/plugins/platforms/xcb/qxcbdrag.cpp b/src/plugins/platforms/xcb/qxcbdrag.cpp
index 61dfe8ac17..6042ec0f87 100644
--- a/src/plugins/platforms/xcb/qxcbdrag.cpp
+++ b/src/plugins/platforms/xcb/qxcbdrag.cpp
@@ -183,7 +183,7 @@ void QXcbDrag::startDrag()
 
     QStringList fmts = QXcbMime::formatsHelper(drag()->mimeData());
     for (int i = 0; i < fmts.size(); ++i) {
-        QList<xcb_atom_t> atoms = QXcbMime::mimeAtomsForFormat(connection(), fmts.at(i));
+        QVector<xcb_atom_t> atoms = QXcbMime::mimeAtomsForFormat(connection(), fmts.at(i));
         for (int j = 0; j < atoms.size(); ++j) {
             if (!drag_types.contains(atoms.at(j)))
                 drag_types.append(atoms.at(j));
@@ -1211,7 +1211,7 @@ QVariant QXcbDropData::xdndObtainData(const QByteArray &format, QVariant::Type r
         return result;
     }
 
-    QList<xcb_atom_t> atoms = drag->xdnd_types;
+    QVector<xcb_atom_t> atoms = drag->xdnd_types;
     QByteArray encoding;
     xcb_atom_t a = mimeAtomForFormat(c, QLatin1String(format), requestedType, atoms, &encoding);
     if (a == XCB_NONE)
diff --git a/src/plugins/platforms/xcb/qxcbdrag.h b/src/plugins/platforms/xcb/qxcbdrag.h
index 183ccf904a..537898db48 100644
--- a/src/plugins/platforms/xcb/qxcbdrag.h
+++ b/src/plugins/platforms/xcb/qxcbdrag.h
@@ -126,7 +126,7 @@ private:
 
     // the types in this drop. 100 is no good, but at least it's big.
     enum { xdnd_max_type = 100 };
-    QList<xcb_atom_t> xdnd_types;
+    QVector<xcb_atom_t> xdnd_types;
 
     // timestamp from XdndPosition and XdndDroptime for retrieving the data
     xcb_timestamp_t target_time;
diff --git a/src/plugins/platforms/xcb/qxcbmime.cpp b/src/plugins/platforms/xcb/qxcbmime.cpp
index b205a63267..c0f6745e7f 100644
--- a/src/plugins/platforms/xcb/qxcbmime.cpp
+++ b/src/plugins/platforms/xcb/qxcbmime.cpp
@@ -136,9 +136,10 @@ bool QXcbMime::mimeDataForAtom(QXcbConnection *connection, xcb_atom_t a, QMimeDa
     return ret;
 }
 
-QList<xcb_atom_t> QXcbMime::mimeAtomsForFormat(QXcbConnection *connection, const QString &format)
+QVector<xcb_atom_t> QXcbMime::mimeAtomsForFormat(QXcbConnection *connection, const QString &format)
 {
-    QList<xcb_atom_t> atoms;
+    QVector<xcb_atom_t> atoms;
+    atoms.reserve(7);
     atoms.append(connection->internAtom(format.toLatin1()));
 
     // special cases for strings
@@ -240,7 +241,7 @@ QVariant QXcbMime::mimeConvertToFormat(QXcbConnection *connection, xcb_atom_t a,
 }
 
 xcb_atom_t QXcbMime::mimeAtomForFormat(QXcbConnection *connection, const QString &format, QVariant::Type requestedType,
-                                 const QList<xcb_atom_t> &atoms, QByteArray *requestedEncoding)
+                                 const QVector<xcb_atom_t> &atoms, QByteArray *requestedEncoding)
 {
     requestedEncoding->clear();
 
diff --git a/src/plugins/platforms/xcb/qxcbmime.h b/src/plugins/platforms/xcb/qxcbmime.h
index 4a69a35ced..563716a75b 100644
--- a/src/plugins/platforms/xcb/qxcbmime.h
+++ b/src/plugins/platforms/xcb/qxcbmime.h
@@ -59,14 +59,14 @@ public:
     QXcbMime();
     ~QXcbMime();
 
-    static QList<xcb_atom_t> mimeAtomsForFormat(QXcbConnection *connection, const QString &format);
+    static QVector<xcb_atom_t> mimeAtomsForFormat(QXcbConnection *connection, const QString &format);
     static QString mimeAtomToString(QXcbConnection *connection, xcb_atom_t a);
     static bool mimeDataForAtom(QXcbConnection *connection, xcb_atom_t a, QMimeData *mimeData, QByteArray *data,
                                 xcb_atom_t *atomFormat, int *dataFormat);
     static QVariant mimeConvertToFormat(QXcbConnection *connection, xcb_atom_t a, const QByteArray &data, const QString &format,
                                         QVariant::Type requestedType, const QByteArray &encoding);
     static xcb_atom_t mimeAtomForFormat(QXcbConnection *connection, const QString &format, QVariant::Type requestedType,
-                                        const QList<xcb_atom_t> &atoms, QByteArray *requestedEncoding);
+                                        const QVector<xcb_atom_t> &atoms, QByteArray *requestedEncoding);
 };
 
 #endif // !(defined(QT_NO_DRAGANDDROP) && defined(QT_NO_CLIPBOARD))