1 files changed, 379 insertions, 0 deletions
diff --git a/src/network/access/qnetworkaccesscache.cpp b/src/network/access/qnetworkaccesscache.cpp
new file mode 100644
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+++ b/src/network/access/qnetworkaccesscache.cpp
@@ -0,0 +1,379 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtNetwork module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qnetworkaccesscache_p.h"
+#include "QtCore/qpointer.h"
+#include "QtCore/qdatetime.h"
+#include "QtCore/qqueue.h"
+#include "qnetworkaccessmanager_p.h"
+#include "qnetworkreply_p.h"
+#include "qnetworkrequest.h"
+
+QT_BEGIN_NAMESPACE
+
+enum ExpiryTimeEnum {
+    ExpiryTime = 120
+};
+
+namespace {
+    struct Receiver
+    {
+        QPointer<QObject> object;
+        const char *member;
+    };
+}
+
+// idea copied from qcache.h
+struct QNetworkAccessCache::Node
+{
+    QDateTime timestamp;
+    QQueue<Receiver> receiverQueue;
+    QByteArray key;
+
+    Node *older, *newer;
+    CacheableObject *object;
+
+    int useCount;
+
+    Node()
+        : older(0), newer(0), object(0), useCount(0)
+    { }
+};
+
+QNetworkAccessCache::CacheableObject::CacheableObject()
+{
+    // leave the members uninitialized
+    // they must be initialized by the derived class's constructor
+}
+
+QNetworkAccessCache::CacheableObject::~CacheableObject()
+{
+#if 0 //def QT_DEBUG
+    if (!key.isEmpty() && Ptr()->hasEntry(key))
+        qWarning() << "QNetworkAccessCache: object" << (void*)this << "key" << key
+                   << "destroyed without being removed from cache first!";
+#endif
+}
+
+void QNetworkAccessCache::CacheableObject::setExpires(bool enable)
+{
+    expires = enable;
+}
+
+void QNetworkAccessCache::CacheableObject::setShareable(bool enable)
+{
+    shareable = enable;
+}
+
+QNetworkAccessCache::QNetworkAccessCache()
+    : oldest(0), newest(0)
+{
+}
+
+QNetworkAccessCache::~QNetworkAccessCache()
+{
+    clear();
+}
+
+void QNetworkAccessCache::clear()
+{
+    NodeHash hashCopy = hash;
+    hash.clear();
+
+    // remove all entries
+    NodeHash::Iterator it = hashCopy.begin();
+    NodeHash::Iterator end = hashCopy.end();
+    for ( ; it != end; ++it) {
+        it->object->key.clear();
+        it->object->dispose();
+    }
+
+    // now delete:
+    hashCopy.clear();
+
+    timer.stop();
+
+    oldest = newest = 0;
+}
+
+/*!
+    Appens the entry given by @p key to the end of the linked list.
+    (i.e., makes it the newest entry)
+ */
+void QNetworkAccessCache::linkEntry(const QByteArray &key)
+{
+    NodeHash::Iterator it = hash.find(key);
+    if (it == hash.end())
+        return;
+
+    Node *const node = &it.value();
+    Q_ASSERT(node != oldest && node != newest);
+    Q_ASSERT(node->older == 0 && node->newer == 0);
+    Q_ASSERT(node->useCount == 0);
+
+    if (newest) {
+        Q_ASSERT(newest->newer == 0);
+        newest->newer = node;
+        node->older = newest;
+    }
+    if (!oldest) {
+        // there are no entries, so this is the oldest one too
+        oldest = node;
+    }
+
+    node->timestamp = QDateTime::currentDateTime().addSecs(ExpiryTime);
+    newest = node;
+}
+
+/*!
+    Removes the entry pointed by @p key from the linked list.
+    Returns true if the entry removed was the oldest one.
+ */
+bool QNetworkAccessCache::unlinkEntry(const QByteArray &key)
+{
+    NodeHash::Iterator it = hash.find(key);
+    if (it == hash.end())
+        return false;
+
+    Node *const node = &it.value();
+
+    bool wasOldest = false;
+    if (node == oldest) {
+        oldest = node->newer;
+        wasOldest = true;
+    }
+    if (node == newest)
+        newest = node->older;
+    if (node->older)
+        node->older->newer = node->newer;
+    if (node->newer)
+        node->newer->older = node->older;
+
+    node->newer = node->older = 0;
+    return wasOldest;
+}
+
+void QNetworkAccessCache::updateTimer()
+{
+    timer.stop();
+
+    if (!oldest)
+        return;
+
+    int interval = QDateTime::currentDateTime().secsTo(oldest->timestamp);
+    if (interval <= 0) {
+        interval = 0;
+    } else {
+        // round up the interval
+        interval = (interval + 15) & ~16;
+    }
+
+    timer.start(interval * 1000, this);
+}
+
+bool QNetworkAccessCache::emitEntryReady(Node *node, QObject *target, const char *member)
+{
+    if (!connect(this, SIGNAL(entryReady(QNetworkAccessCache::CacheableObject*)),
+                 target, member, Qt::QueuedConnection))
+        return false;
+
+    emit entryReady(node->object);
+    disconnect(SIGNAL(entryReady(QNetworkAccessCache::CacheableObject*)));
+
+    return true;
+}
+
+void QNetworkAccessCache::timerEvent(QTimerEvent *)
+{
+    // expire old items
+    QDateTime now = QDateTime::currentDateTime();
+
+    while (oldest && oldest->timestamp < now) {
+        Node *next = oldest->newer;
+        oldest->object->dispose();
+
+        hash.remove(oldest->key); // oldest gets deleted
+        oldest = next;
+    }
+
+    // fixup the list
+    if (oldest)
+        oldest->older = 0;
+    else
+        newest = 0;
+
+    updateTimer();
+}
+
+void QNetworkAccessCache::addEntry(const QByteArray &key, CacheableObject *entry)
+{
+    Q_ASSERT(!key.isEmpty());
+
+    if (unlinkEntry(key))
+        updateTimer();
+
+    Node &node = hash[key];     // create the entry in the hash if it didn't exist
+    if (node.useCount)
+        qWarning("QNetworkAccessCache::addEntry: overriding active cache entry '%s'",
+                 key.constData());
+    if (node.object)
+        node.object->dispose();
+    node.object = entry;
+    node.object->key = key;
+    node.key = key;
+    node.useCount = 1;
+}
+
+bool QNetworkAccessCache::hasEntry(const QByteArray &key) const
+{
+    return hash.contains(key);
+}
+
+bool QNetworkAccessCache::requestEntry(const QByteArray &key, QObject *target, const char *member)
+{
+    NodeHash::Iterator it = hash.find(key);
+    if (it == hash.end())
+        return false;           // no such entry
+
+    Node *node = &it.value();
+
+    if (node->useCount > 0 && !node->object->shareable) {
+        // object is not shareable and is in use
+        // queue for later use
+        Q_ASSERT(node->older == 0 && node->newer == 0);
+        Receiver receiver;
+        receiver.object = target;
+        receiver.member = member;
+        node->receiverQueue.enqueue(receiver);
+
+        // request queued
+        return true;
+    } else {
+        // node not in use or is shareable
+        if (unlinkEntry(key))
+            updateTimer();
+
+        ++node->useCount;
+        return emitEntryReady(node, target, member);
+    }
+}
+
+QNetworkAccessCache::CacheableObject *QNetworkAccessCache::requestEntryNow(const QByteArray &key)
+{
+    NodeHash::Iterator it = hash.find(key);
+    if (it == hash.end())
+        return 0;
+    if (it->useCount > 0) {
+        if (it->object->shareable) {
+            ++it->useCount;
+            return it->object;
+        }
+
+        // object in use and not shareable
+        return 0;
+    }
+
+    // entry not in use, let the caller have it
+    bool wasOldest = unlinkEntry(key);
+    ++it->useCount;
+
+    if (wasOldest)
+        updateTimer();
+    return it->object;
+}
+
+void QNetworkAccessCache::releaseEntry(const QByteArray &key)
+{
+    NodeHash::Iterator it = hash.find(key);
+    if (it == hash.end()) {
+        qWarning("QNetworkAccessCache::releaseEntry: trying to release key '%s' that is not in cache",
+                 key.constData());
+        return;
+    }
+
+    Node *node = &it.value();
+    Q_ASSERT(node->useCount > 0);
+
+    // are there other objects waiting?
+    if (!node->receiverQueue.isEmpty()) {
+        // queue another activation
+        Receiver receiver;
+        do {
+            receiver = node->receiverQueue.dequeue();
+        } while (receiver.object.isNull() && !node->receiverQueue.isEmpty());
+
+        if (!receiver.object.isNull()) {
+            emitEntryReady(node, receiver.object, receiver.member);
+            return;
+        }
+    }
+
+    if (!--node->useCount) {
+        // no objects waiting; add it back to the expiry list
+        if (node->object->expires)
+            linkEntry(key);
+
+        if (oldest == node)
+            updateTimer();
+    }
+}
+
+void QNetworkAccessCache::removeEntry(const QByteArray &key)
+{
+    NodeHash::Iterator it = hash.find(key);
+    if (it == hash.end()) {
+        qWarning("QNetworkAccessCache::removeEntry: trying to remove key '%s' that is not in cache",
+                 key.constData());
+        return;
+    }
+
+    Node *node = &it.value();
+    if (unlinkEntry(key))
+        updateTimer();
+    if (node->useCount > 1)
+        qWarning("QNetworkAccessCache::removeEntry: removing active cache entry '%s'",
+                 key.constData());
+
+    node->object->key.clear();
+    hash.remove(node->key);
+}
+
+QT_END_NAMESPACE