diff options
Diffstat (limited to 'src/network/kernel/qhostinfo.cpp')
| -rw-r--r-- | src/network/kernel/qhostinfo.cpp | 161 |
1 files changed, 150 insertions, 11 deletions
diff --git a/src/network/kernel/qhostinfo.cpp b/src/network/kernel/qhostinfo.cpp index 93f6d13..4800e9d 100644 --- a/src/network/kernel/qhostinfo.cpp +++ b/src/network/kernel/qhostinfo.cpp @@ -112,6 +112,13 @@ Q_GLOBAL_STATIC(QHostInfoLookupManager, theHostInfoLookupManager) To retrieve the name of the local host, use the static QHostInfo::localHostName() function. + \note Since Qt 4.6.1 QHostInfo is using multiple threads for DNS lookup + instead of one dedicated DNS thread. This improves performance, + but also changes the order of signal emissions when using lookupHost() + compared to previous versions of Qt. + \note Since Qt 4.6.3 QHostInfo is using a small internal 60 second DNS cache + for performance improvements. + \sa QAbstractSocket, {http://www.rfc-editor.org/rfc/rfc3492.txt}{RFC 3492} */ @@ -181,9 +188,26 @@ int QHostInfo::lookupHost(const QString &name, QObject *receiver, receiver, member, Qt::QueuedConnection); result.data()->emitResultsReady(hostInfo); #else - QHostInfoRunnable* runnable = new QHostInfoRunnable(name, id); - QObject::connect(&runnable->resultEmitter, SIGNAL(resultsReady(QHostInfo)), receiver, member, Qt::QueuedConnection); - theHostInfoLookupManager()->scheduleLookup(runnable); + QHostInfoLookupManager *manager = theHostInfoLookupManager(); + if (manager) { + // the application is still alive + if (manager->cache.isEnabled()) { + // check cache first + bool valid = false; + QHostInfo info = manager->cache.get(name, &valid); + if (valid) { + info.setLookupId(id); + QHostInfoResult result; + QObject::connect(&result, SIGNAL(resultsReady(QHostInfo)), receiver, member, Qt::QueuedConnection); + result.emitResultsReady(info); + return id; + } + } + // cache is not enabled or it was not in the cache, do normal lookup + QHostInfoRunnable* runnable = new QHostInfoRunnable(name, id); + QObject::connect(&runnable->resultEmitter, SIGNAL(resultsReady(QHostInfo)), receiver, member, Qt::QueuedConnection); + manager->scheduleLookup(runnable); + } #endif return id; @@ -418,14 +442,24 @@ void QHostInfoRunnable::run() return; } - // check cache - // FIXME - - // if not in cache: OS lookup - QHostInfo hostInfo = QHostInfoAgent::fromName(toBeLookedUp); - - // save to cache - // FIXME + QHostInfo hostInfo; + + // QHostInfo::lookupHost already checks the cache. However we need to check + // it here too because it might have been cache saved by another QHostInfoRunnable + // in the meanwhile while this QHostInfoRunnable was scheduled but not running + if (manager->cache.isEnabled()) { + // check the cache first + bool valid = false; + hostInfo = manager->cache.get(toBeLookedUp, &valid); + if (!valid) { + // not in cache, we need to do the lookup and store the result in the cache + hostInfo = QHostInfoAgent::fromName(toBeLookedUp); + manager->cache.put(toBeLookedUp, hostInfo); + } + } else { + // cache is not enabled, just do the lookup and continue + hostInfo = QHostInfoAgent::fromName(toBeLookedUp); + } // check aborted again if (manager->wasAborted(id)) { @@ -451,6 +485,11 @@ QHostInfoLookupManager::QHostInfoLookupManager() : mutex(QMutex::Recursive), was QHostInfoLookupManager::~QHostInfoLookupManager() { wasDeleted = true; + + // don't qDeleteAll currentLookups, the QThreadPool has ownership + qDeleteAll(postponedLookups); + qDeleteAll(scheduledLookups); + qDeleteAll(finishedLookups); } void QHostInfoLookupManager::work() @@ -570,6 +609,106 @@ void QHostInfoLookupManager::lookupFinished(QHostInfoRunnable *r) work(); } +// This function returns immediatly when we had a result in the cache, else it will later emit a signal +QHostInfo qt_qhostinfo_lookup(const QString &name, QObject *receiver, const char *member, bool *valid, int *id) +{ + *valid = false; + *id = -1; + + // check cache + QHostInfoLookupManager* manager = theHostInfoLookupManager(); + if (manager && manager->cache.isEnabled()) { + QHostInfo info = manager->cache.get(name, valid); + if (*valid) { + return info; + } + } + + // was not in cache, trigger lookup + *id = QHostInfo::lookupHost(name, receiver, member); + + // return empty response, valid==false + return QHostInfo(); +} + +void qt_qhostinfo_clear_cache() +{ + QHostInfoLookupManager* manager = theHostInfoLookupManager(); + if (manager) { + manager->cache.clear(); + } +} + +void Q_NETWORK_EXPORT qt_qhostinfo_enable_cache(bool e) +{ + QHostInfoLookupManager* manager = theHostInfoLookupManager(); + if (manager) { + manager->cache.setEnabled(e); + } +} + +// cache for 60 seconds +// cache 64 items +QHostInfoCache::QHostInfoCache() : max_age(60), enabled(true), cache(64) +{ +#ifdef QT_QHOSTINFO_CACHE_DISABLED_BY_DEFAULT + enabled = false; +#endif +} + +bool QHostInfoCache::isEnabled() +{ + return enabled; +} + +// this function is currently only used for the auto tests +// and not usable by public API +void QHostInfoCache::setEnabled(bool e) +{ + enabled = e; +} + + +QHostInfo QHostInfoCache::get(const QString &name, bool *valid) +{ + QMutexLocker locker(&this->mutex); + + *valid = false; + if (cache.contains(name)) { + QHostInfoCacheElement *element = cache.object(name); + if (element->age.elapsed() < max_age*1000) + *valid = true; + return element->info; + + // FIXME idea: + // if too old but not expired, trigger a new lookup + // to freshen our cache + } + + return QHostInfo(); +} + +void QHostInfoCache::put(const QString &name, const QHostInfo &info) +{ + // if the lookup failed, don't cache + if (info.error() != QHostInfo::NoError) + return; + + QHostInfoCacheElement* element = new QHostInfoCacheElement(); + element->info = info; + element->age = QTime(); + element->age.start(); + + QMutexLocker locker(&this->mutex); + cache.insert(name, element); // cache will take ownership +} + +void QHostInfoCache::clear() +{ + QMutexLocker locker(&this->mutex); + cache.clear(); +} + #endif // QT_NO_THREAD QT_END_NAMESPACE |