xcb: avoid unnecessary InternAtom requests

QXcbConnection::internAtom() creates the atom if it does not exist. The
lifetime of an atom is not tied to the interning client. Atoms remain
defined until server reset (lost connection, restart).

So create the atom once via QXcbConnection::initializeAllAtoms(), and
later fetch the atom value from local array, instead of repeating
InternAtom requests.

Change-Id: I3cae21895febad6e5daf8c32e72612202baaad64
Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>

5 files changed, 18 insertions, 12 deletions

diff --git a/src/plugins/platforms/xcb/qxcbclipboard.cpp b/src/plugins/platforms/xcb/qxcbclipboard.cpp
index ca2eff170d..84831cdbe5 100644
--- a/src/plugins/platforms/xcb/qxcbclipboard.cpp
+++ b/src/plugins/platforms/xcb/qxcbclipboard.cpp
@@ -832,7 +832,7 @@ xcb_generic_event_t *QXcbClipboard::waitForClipboardEvent(xcb_window_t window, i
         }
 
         // process other clipboard events, since someone is probably requesting data from us
-        auto clipboardAtom = connection()->internAtom("CLIPBOARD");
+        auto clipboardAtom = atom(QXcbAtom::CLIPBOARD);
         e = connection()->checkEvent([clipboardAtom](xcb_generic_event_t *event, int type) {
             xcb_atom_t selection = XCB_ATOM_NONE;
             if (type == XCB_SELECTION_REQUEST)
diff --git a/src/plugins/platforms/xcb/qxcbconnection.cpp b/src/plugins/platforms/xcb/qxcbconnection.cpp
index 75275f6fd2..84551fd74b 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.cpp
+++ b/src/plugins/platforms/xcb/qxcbconnection.cpp
@@ -1964,6 +1964,10 @@ static const char * xcb_atomnames = {
     "_COMPIZ_DECOR_DELETE_PIXMAP\0"
     "_COMPIZ_TOOLKIT_ACTION\0"
     "_GTK_LOAD_ICONTHEMES\0"
+    "AT_SPI_BUS\0"
+    "EDID\0"
+    "EDID_DATA\0"
+    "XFree86_DDC_EDID1_RAWDATA\0"
     // \0\0 terminates loop.
 };
 
diff --git a/src/plugins/platforms/xcb/qxcbconnection.h b/src/plugins/platforms/xcb/qxcbconnection.h
index 342efca55e..596174d234 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.h
+++ b/src/plugins/platforms/xcb/qxcbconnection.h
@@ -295,6 +295,12 @@ namespace QXcbAtom {
         _COMPIZ_TOOLKIT_ACTION,
         _GTK_LOAD_ICONTHEMES,
 
+        AT_SPI_BUS,
+
+        EDID,
+        EDID_DATA,
+        XFree86_DDC_EDID1_RAWDATA,
+
         NAtoms
     };
 }
diff --git a/src/plugins/platforms/xcb/qxcbnativeinterface.cpp b/src/plugins/platforms/xcb/qxcbnativeinterface.cpp
index 3d2197796f..98bedea48a 100644
--- a/src/plugins/platforms/xcb/qxcbnativeinterface.cpp
+++ b/src/plugins/platforms/xcb/qxcbnativeinterface.cpp
@@ -408,7 +408,7 @@ void *QXcbNativeInterface::atspiBus()
     QXcbIntegration *integration = static_cast<QXcbIntegration *>(QGuiApplicationPrivate::platformIntegration());
     QXcbConnection *defaultConnection = integration->defaultConnection();
     if (defaultConnection) {
-        xcb_atom_t atspiBusAtom = defaultConnection->internAtom("AT_SPI_BUS");
+        auto atspiBusAtom = defaultConnection->atom(QXcbAtom::AT_SPI_BUS);
         auto reply = Q_XCB_REPLY(xcb_get_property, defaultConnection->xcb_connection(),
                                      false, defaultConnection->rootWindow(),
                                      atspiBusAtom, XCB_ATOM_STRING, 0, 128);
diff --git a/src/plugins/platforms/xcb/qxcbscreen.cpp b/src/plugins/platforms/xcb/qxcbscreen.cpp
index b398768bbc..8c0ce8dd7e 100644
--- a/src/plugins/platforms/xcb/qxcbscreen.cpp
+++ b/src/plugins/platforms/xcb/qxcbscreen.cpp
@@ -906,16 +906,12 @@ QByteArray QXcbScreen::getEdid() const
         return result;
 
     // Try a bunch of atoms
-    xcb_atom_t atom = connection()->internAtom("EDID");
-    result = getOutputProperty(atom);
-    if (result.isEmpty()) {
-        atom = connection()->internAtom("EDID_DATA");
-        result = getOutputProperty(atom);
-    }
-    if (result.isEmpty()) {
-        atom = connection()->internAtom("XFree86_DDC_EDID1_RAWDATA");
-        result = getOutputProperty(atom);
-    }
+    result = getOutputProperty(atom(QXcbAtom::EDID));
+    if (result.isEmpty())
+        result = getOutputProperty(atom(QXcbAtom::EDID_DATA));
+    if (result.isEmpty())
+        result = getOutputProperty(atom(QXcbAtom::XFree86_DDC_EDID1_RAWDATA));
+
     return result;
 }