From 1e8479b2aa781e6ce3fadf01294023fbc6ddbc22 Mon Sep 17 00:00:00 2001
From: Konstantin Ritt <ritt.ks@gmail.com>
Date: Fri, 7 Oct 2011 14:45:47 +0200
Subject: don't lock the global mutex if there is nothing to protect

according to Thiago, setting the pointer with the same values *is* thread-safe

Merge-request: 2655
Reviewed-by: Jan-Arve Saether <jan-arve.saether@nokia.com>
---
 src/corelib/kernel/qeventdispatcher_win.cpp |  6 ------
 src/gui/dialogs/qfiledialog_win.cpp         | 17 -----------------
 src/network/kernel/qhostinfo_win.cpp        | 20 ++++++++------------
 src/plugins/bearer/nativewifi/main.cpp      | 14 +-------------
 4 files changed, 9 insertions(+), 48 deletions(-)

diff --git a/src/corelib/kernel/qeventdispatcher_win.cpp b/src/corelib/kernel/qeventdispatcher_win.cpp
index 365b28e..c135c4a 100644
--- a/src/corelib/kernel/qeventdispatcher_win.cpp
+++ b/src/corelib/kernel/qeventdispatcher_win.cpp
@@ -53,7 +53,6 @@
 #include "qabstracteventdispatcher_p.h"
 #include "qcoreapplication_p.h"
 #include <private/qthread_p.h>
-#include <private/qmutexpool_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -322,11 +321,6 @@ static void resolveTimerAPI()
 {
     static bool triedResolve = false;
     if (!triedResolve) {
-#ifndef QT_NO_THREAD
-        QMutexLocker locker(QMutexPool::globalInstanceGet(&triedResolve));
-        if (triedResolve)
-            return;
-#endif
 #ifndef Q_OS_WINCE
         QSystemLibrary library(QLatin1String("Mmtimer"));
 #else
diff --git a/src/gui/dialogs/qfiledialog_win.cpp b/src/gui/dialogs/qfiledialog_win.cpp
index 45f6164..32dbe4f 100644
--- a/src/gui/dialogs/qfiledialog_win.cpp
+++ b/src/gui/dialogs/qfiledialog_win.cpp
@@ -55,10 +55,6 @@
 #include <private/qsystemlibrary_p.h>
 #include "qfiledialog_win_p.h"
 
-#ifndef QT_NO_THREAD
-#  include <private/qmutexpool_p.h>
-#endif
-
 #ifdef Q_WS_WINCE
 #include <commdlg.h>
 bool qt_priv_ptr_valid = false;
@@ -83,20 +79,7 @@ QT_BEGIN_NAMESPACE
 static void qt_win_resolve_libs()
 {
     static bool triedResolve = false;
-
     if (!triedResolve) {
-#ifndef QT_NO_THREAD
-        // protect initialization
-        QMutexLocker locker(QMutexPool::globalInstanceGet(&triedResolve));
-        // check triedResolve again, since another thread may have already
-        // done the initialization
-        if (triedResolve) {
-            // another thread did initialize the security function pointers,
-            // so we shouldn't do it again.
-            return;
-        }
-#endif
-
 #if !defined(Q_WS_WINCE)
         QSystemLibrary lib(QLatin1String("shell32"));
         ptrSHBrowseForFolder = (PtrSHBrowseForFolder)lib.resolve("SHBrowseForFolderW");
diff --git a/src/network/kernel/qhostinfo_win.cpp b/src/network/kernel/qhostinfo_win.cpp
index 03e72c4..1cbf350 100644
--- a/src/network/kernel/qhostinfo_win.cpp
+++ b/src/network/kernel/qhostinfo_win.cpp
@@ -45,9 +45,7 @@
 #include "private/qnativesocketengine_p.h"
 #include <ws2tcpip.h>
 #include <private/qsystemlibrary_p.h>
-#include <qmutex.h>
 #include <qurl.h>
-#include <private/qmutexpool_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -84,6 +82,10 @@ static void resolveLibrary()
 {
     // Attempt to resolve getaddrinfo(); without it we'll have to fall
     // back to gethostbyname(), which has no IPv6 support.
+    static bool triedResolve = false;
+    if (triedResolve)
+        return;
+
 #if !defined(Q_OS_WINCE)
     QSystemLibrary ws2lib(QLatin1String("ws2_32"));
 #else
@@ -94,6 +96,8 @@ static void resolveLibrary()
         local_freeaddrinfo = (freeaddrinfoProto)ws2lib.resolve("freeaddrinfo");
         local_getnameinfo = (getnameinfoProto)ws2lib.resolve("getnameinfo");
     }
+
+    triedResolve = true;
 }
 
 #if defined(Q_OS_WINCE)
@@ -103,21 +107,13 @@ QMutex qPrivCEMutex;
 
 QHostInfo QHostInfoAgent::fromName(const QString &hostName)
 {
+    resolveLibrary();
+
 #if defined(Q_OS_WINCE)
     QMutexLocker locker(&qPrivCEMutex);
 #endif
     QWindowsSockInit winSock;
 
-    // Load res_init on demand.
-    static volatile bool triedResolve = false;
-    if (!triedResolve) {
-        QMutexLocker locker(QMutexPool::globalInstanceGet(&local_getaddrinfo));
-        if (!triedResolve) {
-            resolveLibrary();
-            triedResolve = true;
-        }
-    }
-
     QHostInfo results;
 
 #if defined(QHOSTINFO_DEBUG)
diff --git a/src/plugins/bearer/nativewifi/main.cpp b/src/plugins/bearer/nativewifi/main.cpp
index cbdfd99..d279631 100644
--- a/src/plugins/bearer/nativewifi/main.cpp
+++ b/src/plugins/bearer/nativewifi/main.cpp
@@ -42,30 +42,18 @@
 #include "qnativewifiengine.h"
 #include "platformdefs.h"
 
-#include <QtCore/qmutex.h>
-#include <QtCore/private/qmutexpool_p.h>
 #include <QtCore/private/qsystemlibrary_p.h>
 
 #include <QtNetwork/private/qbearerplugin_p.h>
 
-#include <QtCore/qdebug.h>
-
 #ifndef QT_NO_BEARERMANAGEMENT
 
 QT_BEGIN_NAMESPACE
 
 static void resolveLibrary()
 {
-    static volatile bool triedResolve = false;
-
+    static bool triedResolve = false;
     if (!triedResolve) {
-#ifndef QT_NO_THREAD
-        QMutexLocker locker(QMutexPool::globalInstanceGet(&local_WlanOpenHandle));
-#endif
-
-        if (triedResolve)
-            return;
-
         QSystemLibrary wlanapi(QLatin1String("wlanapi"));
         if (wlanapi.load()) {
             local_WlanOpenHandle = (WlanOpenHandleProto)
-- 
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