XCB: simplify atom registration code

There's no need of calculating offsets into the \0-separated string
of atom names; since we're going to iterate that string exactly once,
do that, and register the corresponding atom name as we iterate.

(This means that solutions that calculate the offsets at compile-time,
like qOffsetStringArray, are also overkill for the use case).

Change-Id: I71ed512dee4f2a8bfb99ca2392efbd8a07f2a7c1
Reviewed-by: JiDe Zhang <zhangjide@uniontech.com>
Reviewed-by: Liang Qi <liang.qi@qt.io>
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 8 insertions, 14 deletions

diff --git a/src/plugins/platforms/xcb/qxcbatom.cpp b/src/plugins/platforms/xcb/qxcbatom.cpp
index 6cb6d29de2..09b1fe8a9d 100644
--- a/src/plugins/platforms/xcb/qxcbatom.cpp
+++ b/src/plugins/platforms/xcb/qxcbatom.cpp
@@ -215,24 +215,18 @@ void QXcbAtom::initialize(xcb_connection_t *connection)
 }
 
 void QXcbAtom::initializeAllAtoms(xcb_connection_t *connection) {
-    const char *names[QXcbAtom::NAtoms];
-    const char *ptr = xcb_atomnames;
-
+    const char *name = xcb_atomnames;
+    size_t name_len;
     int i = 0;
-    while (*ptr) {
-        names[i++] = ptr;
-        while (*ptr)
-            ++ptr;
-        ++ptr;
-    }
-
-    Q_ASSERT(i == QXcbAtom::NAtoms);
-
     xcb_intern_atom_cookie_t cookies[QXcbAtom::NAtoms];
 
+    while ((name_len = strlen(name)) != 0) {
+        cookies[i] = xcb_intern_atom(connection, false, name_len, name);
+        ++i;
+        name += name_len + 1; // jump over the \0
+    }
+
     Q_ASSERT(i == QXcbAtom::NAtoms);
-    for (i = 0; i < QXcbAtom::NAtoms; ++i)
-        cookies[i] = xcb_intern_atom(connection, false, strlen(names[i]), names[i]);
 
     for (i = 0; i < QXcbAtom::NAtoms; ++i) {
         xcb_intern_atom_reply_t *reply = xcb_intern_atom_reply(connection, cookies[i], nullptr);