QtNetwork: replace Java-style iterators

... with STL-style iterators or with algorithms.
Java-style iterators have overhead.

Introduce local template separate_if algorithm from kleopatra
project to simplify current code.
http://api.kde.org/4.3-api/kdepim-apidocs/kleopatra/html

Done-with: Marc Mutz <marc.mutz@kdab.com>
Change-Id: Ib154f80f46f8041d9cafd81bed0e1982b21541cf
Reviewed-by: Edward Welbourne <edward.welbourne@theqtcompany.com>
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

src/network/bearer/qnetworkconfiguration.cpp

@@ -384,25 +384,21 @@ QList<QNetworkConfiguration> QNetworkConfiguration::children() const
     if (d->type != QNetworkConfiguration::ServiceNetwork || !d->isValid)
         return results;
 
-    QMutableMapIterator<unsigned int, QNetworkConfigurationPrivatePointer> i(d->serviceNetworkMembers);
-    while (i.hasNext()) {
-        i.next();
-
-        QNetworkConfigurationPrivatePointer p = i.value();
-
+    for (auto it = d->serviceNetworkMembers.begin(), end = d->serviceNetworkMembers.end(); it != end;) {
+        QNetworkConfigurationPrivatePointer p = it.value();
         //if we have an invalid member get rid of it -> was deleted earlier on
         {
             QMutexLocker childLocker(&p->mutex);
 
             if (!p->isValid) {
-                i.remove();
+                it = d->serviceNetworkMembers.erase(it);
                 continue;
             }
         }
-
         QNetworkConfiguration item;
         item.d = p;
         results << item;
+        ++it;
     }
 
     return results;

src/network/kernel/qhostinfo.cpp

@@ -79,6 +79,22 @@ bool any_of(InputIt first, InputIt last, UnaryPredicate p)
 {
     return std::find_if(first, last, p) != last;
 }
+
+template <typename InputIt, typename OutputIt1, typename OutputIt2, typename UnaryPredicate>
+std::pair<OutputIt1, OutputIt2> separate_if(InputIt first, InputIt last, OutputIt1 dest1, OutputIt2 dest2, UnaryPredicate p)
+{
+    while (first != last) {
+        if (p(*first)) {
+            *dest1 = *first;
+            ++dest1;
+        } else {
+            *dest2 = *first;
+            ++dest2;
+        }
+        ++first;
+    }
+    return std::make_pair(dest1, dest2);
+}
 }
 
 /*!
@@ -587,46 +603,37 @@ void QHostInfoLookupManager::work()
         finishedLookups.clear();
     }
 
-    if (!postponedLookups.isEmpty()) {
-        // try to start the postponed ones
+    auto isAlreadyRunning = [this](QHostInfoRunnable *lookup) {
+        return any_of(currentLookups.cbegin(), currentLookups.cend(), ToBeLookedUpEquals(lookup->toBeLookedUp));
+    };
 
-        QMutableListIterator<QHostInfoRunnable*> iterator(postponedLookups);
-        while (iterator.hasNext()) {
-            QHostInfoRunnable* postponed = iterator.next();
+    // Transfer any postponed lookups that aren't currently running to the scheduled list, keeping already-running lookups:
+    postponedLookups.erase(separate_if(postponedLookups.begin(),
+                                       postponedLookups.end(),
+                                       postponedLookups.begin(),
+                                       std::front_inserter(scheduledLookups), // prepend! we want to finish it ASAP
+                                       isAlreadyRunning).first,
+                           postponedLookups.end());
 
-            // check if none of the postponed hostnames is currently running
-            const bool alreadyRunning = any_of(currentLookups.cbegin(), currentLookups.cend(), ToBeLookedUpEquals(postponed->toBeLookedUp));
-            if (!alreadyRunning) {
-                iterator.remove();
-                scheduledLookups.prepend(postponed); // prepend! we want to finish it ASAP
-            }
+    // Unschedule and postpone any that are currently running:
+    scheduledLookups.erase(separate_if(scheduledLookups.begin(),
+                                       scheduledLookups.end(),
+                                       std::back_inserter(postponedLookups),
+                                       scheduledLookups.begin(),
+                                       isAlreadyRunning).second,
+                           scheduledLookups.end());
+
+    const int availableThreads = threadPool.maxThreadCount() - currentLookups.size();
+    if (availableThreads > 0) {
+        int readyToStartCount = qMin(availableThreads, scheduledLookups.size());
+        auto it = scheduledLookups.begin();
+        while (readyToStartCount--) {
+            // runnable now running in new thread, track this in currentLookups
+            threadPool.start(*it);
+            currentLookups.push_back(std::move(*it));
+            ++it;
         }
-    }
-
-    if (!scheduledLookups.isEmpty()) {
-        // try to start the new ones
-        QMutableListIterator<QHostInfoRunnable*> iterator(scheduledLookups);
-        while (iterator.hasNext()) {
-            QHostInfoRunnable *scheduled = iterator.next();
-
-            // check if a lookup for this host is already running, then postpone
-            const bool alreadyRunning = any_of(currentLookups.cbegin(), currentLookups.cend(), ToBeLookedUpEquals(scheduled->toBeLookedUp));
-            if (alreadyRunning) {
-                iterator.remove();
-                postponedLookups.append(scheduled);
-                scheduled = 0;
-            }
-
-            if (scheduled && currentLookups.size() < threadPool.maxThreadCount()) {
-                // runnable now running in new thread, track this in currentLookups
-                threadPool.start(scheduled);
-                iterator.remove();
-                currentLookups.append(scheduled);
-            } else {
-                // was postponed, continue iterating
-                continue;
-            }
-        };
+        scheduledLookups.erase(scheduledLookups.begin(), it);
     }
 }
 

src/network/socket/qsocks5socketengine.cpp

@@ -396,12 +396,12 @@ void QSocks5BindStore::timerEvent(QTimerEvent * event)
     QMutexLocker lock(&mutex);
     if (event->timerId() == sweepTimerId) {
         QSOCKS5_DEBUG << "QSocks5BindStore performing sweep";
-        QMutableHashIterator<int, QSocks5BindData *> it(store);
-        while (it.hasNext()) {
-            it.next();
+        for (auto it = store.begin(), end = store.end(); it != end;) {
             if (it.value()->timeStamp.hasExpired(350000)) {
                 QSOCKS5_DEBUG << "QSocks5BindStore removing JJJJ";
-                it.remove();
+                it = store.erase(it);
+            } else {
+                ++it;
             }
         }
     }

src/network/ssl/qsslsocket_openssl.cpp

@@ -747,9 +747,8 @@ QList<QSslCertificate> QSslSocketPrivate::systemCaCertificates()
                 certFiles.insert(it.fileInfo().canonicalFilePath());
             }
         }
-        QSetIterator<QString> it(certFiles);
-        while (it.hasNext())
-            systemCerts.append(QSslCertificate::fromPath(it.next(), platformEncodingFormat));
+        for (const QString& file : qAsConst(certFiles))
+            systemCerts.append(QSslCertificate::fromPath(file, platformEncodingFormat));
 # ifndef Q_OS_ANDROID
         systemCerts.append(QSslCertificate::fromPath(QLatin1String("/etc/pki/tls/certs/ca-bundle.crt"), QSsl::Pem)); // Fedora, Mandriva
         systemCerts.append(QSslCertificate::fromPath(QLatin1String("/usr/local/share/certs/ca-root-nss.crt"), QSsl::Pem)); // FreeBSD's ca_root_nss