From 28fbd13e22935483d9ebcf2f088681f3d649cf2a Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@kdab.com>
Date: Tue, 5 Dec 2017 15:24:57 +0100
Subject: xcb: use a more efficient unique_ptr instantiation

Wrap std::free() in a function object, to avoid having to carry around
state (the function pointer) inside unique_ptr objects. This shrinks
unique_ptrs back to sizeof(void*).

Change-Id: I32a711192c5485dc04e3b36a1ddabf02d1e9d4f9
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>
---
 src/plugins/platforms/xcb/qxcbconnection.h | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

(limited to 'src/plugins')

diff --git a/src/plugins/platforms/xcb/qxcbconnection.h b/src/plugins/platforms/xcb/qxcbconnection.h
index 725c01f77d..ded11525c1 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.h
+++ b/src/plugins/platforms/xcb/qxcbconnection.h
@@ -757,16 +757,18 @@ private:
 
 #define Q_XCB_REPLY_CONNECTION_ARG(connection, ...) connection
 
+struct QStdFreeDeleter {
+    void operator()(void *p) const Q_DECL_NOTHROW { return std::free(p); }
+};
+
 #define Q_XCB_REPLY(call, ...) \
-    std::unique_ptr<call##_reply_t, decltype(std::free) *>( \
-        call##_reply(Q_XCB_REPLY_CONNECTION_ARG(__VA_ARGS__), call(__VA_ARGS__), nullptr), \
-        std::free \
+    std::unique_ptr<call##_reply_t, QStdFreeDeleter>( \
+        call##_reply(Q_XCB_REPLY_CONNECTION_ARG(__VA_ARGS__), call(__VA_ARGS__), nullptr) \
     )
 
 #define Q_XCB_REPLY_UNCHECKED(call, ...) \
-    std::unique_ptr<call##_reply_t, decltype(std::free) *>( \
-        call##_reply(Q_XCB_REPLY_CONNECTION_ARG(__VA_ARGS__), call##_unchecked(__VA_ARGS__), nullptr), \
-        std::free \
+    std::unique_ptr<call##_reply_t, QStdFreeDeleter>( \
+        call##_reply(Q_XCB_REPLY_CONNECTION_ARG(__VA_ARGS__), call##_unchecked(__VA_ARGS__), nullptr) \
     )
 
 template <typename T>
-- 
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