QNetworkAccessCache Class Reference

#include <qnetworkaccesscache_p.h>

Inheritance diagram for QNetworkAccessCache:

Classes
class	CacheableObject
struct	Node

Public Types
typedef QHash< QByteArray, Node >	NodeHash

Signals
void	entryReady (QNetworkAccessCache::CacheableObject *)
Signals inherited from QObject
void	destroyed (QObject *=0)
	This signal is emitted immediately before the object obj is destroyed, and can not be blocked. More...

Public Functions
void	addEntry (const QByteArray &key, CacheableObject *entry)
void	clear ()
bool	hasEntry (const QByteArray &key) const
	QNetworkAccessCache ()
void	releaseEntry (const QByteArray &key)
void	removeEntry (const QByteArray &key)
bool	requestEntry (const QByteArray &key, QObject *target, const char *member)
CacheableObject *	requestEntryNow (const QByteArray &key)
	~QNetworkAccessCache ()
Public Functions inherited from QObject
bool	blockSignals (bool b)
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). More...
const QObjectList &	children () const
	Returns a list of child objects. More...
bool	connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
bool	disconnect (const char *signal=0, const QObject *receiver=0, const char *member=0)
bool	disconnect (const QObject *receiver, const char *member=0)
void	dumpObjectInfo ()
	Dumps information about signal connections, etc. More...
void	dumpObjectTree ()
	Dumps a tree of children to the debug output. More...
QList< QByteArray >	dynamicPropertyNames () const
	Returns the names of all properties that were dynamically added to the object using setProperty(). More...
virtual bool	event (QEvent *)
	This virtual function receives events to an object and should return true if the event e was recognized and processed. More...
virtual bool	eventFilter (QObject *, QEvent *)
	Filters events if this object has been installed as an event filter for the watched object. More...
template<typename T >
T	findChild (const QString &aName=QString()) const
	Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. More...
template<typename T >
QList< T >	findChildren (const QString &aName=QString()) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. More...
template<typename T >
QList< T >	findChildren (const QRegExp &re) const
bool	inherits (const char *classname) const
	Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false. More...
void	installEventFilter (QObject *)
	Installs an event filter filterObj on this object. More...
bool	isWidgetType () const
	Returns true if the object is a widget; otherwise returns false. More...
void	killTimer (int id)
	Kills the timer with timer identifier, id. More...
virtual const QMetaObject *	metaObject () const
	Returns a pointer to the meta-object of this object. More...
void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children. More...
QString	objectName () const
QObject *	parent () const
	Returns a pointer to the parent object. More...
QVariant	property (const char *name) const
	Returns the value of the object's name property. More...
Q_INVOKABLE	QObject (QObject *parent=0)
	Constructs an object with parent object parent. More...
void	removeEventFilter (QObject *)
	Removes an event filter object obj from this object. More...
void	setObjectName (const QString &name)
void	setParent (QObject *)
	Makes the object a child of parent. More...
bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value. More...
void	setUserData (uint id, QObjectUserData *data)
bool	signalsBlocked () const
	Returns true if signals are blocked; otherwise returns false. More...
int	startTimer (int interval)
	Starts a timer and returns a timer identifier, or returns zero if it could not start a timer. More...
QThread *	thread () const
	Returns the thread in which the object lives. More...
QObjectUserData *	userData (uint id) const
virtual	~QObject ()
	Destroys the object, deleting all its child objects. More...

Protected Functions
void	timerEvent (QTimerEvent *)
	This event handler can be reimplemented in a subclass to receive timer events for the object. More...
Protected Functions inherited from QObject
virtual void	childEvent (QChildEvent *)
	This event handler can be reimplemented in a subclass to receive child events. More...
virtual void	connectNotify (const char *signal)
	This virtual function is called when something has been connected to signal in this object. More...
virtual void	customEvent (QEvent *)
	This event handler can be reimplemented in a subclass to receive custom events. More...
virtual void	disconnectNotify (const char *signal)
	This virtual function is called when something has been disconnected from signal in this object. More...
	QObject (QObjectPrivate &dd, QObject *parent=0)
int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal. More...
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns 0. More...
int	senderSignalIndex () const

Private Functions
bool	emitEntryReady (Node *node, QObject *target, const char *member)
void	linkEntry (const QByteArray &key)
	Appens the entry given by key to the end of the linked list. More...
bool	unlinkEntry (const QByteArray &key)
	Removes the entry pointed by key from the linked list. More...
void	updateTimer ()

Properties
NodeHash	hash
Node *	newest
Node *	oldest
QBasicTimer	timer

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()
	Schedules this object for deletion. More...
Static Public Functions inherited from QObject
static bool	connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
	Creates a connection of the given type from the signal in the sender object to the method in the receiver object. More...
static bool	connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
static bool	disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
	Disconnects signal in object sender from method in object receiver. More...
static bool	disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
static uint	registerUserData ()
static QString	tr (const char *sourceText, const char *comment=0, int n=-1)
static QString	trUtf8 (const char *sourceText, const char *comment=0, int n=-1)
Static Public Variables inherited from QObject
static const QMetaObject	staticMetaObject
	This variable stores the meta-object for the class. More...
Protected Variables inherited from QObject
QScopedPointer< QObjectData >	d_ptr
Static Protected Variables inherited from QObject
static const QMetaObject	staticQtMetaObject
Related Functions inherited from QObject
T	qFindChildqFindChildren (const QObject *obj, const QString &name)()
QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()
QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QRegExp &regExp)()
T *	qobject_cast (QObject *object)
	QObjectList
void *	qt_find_obj_child (QObject *parent, const char *type, const QString &name)
	Returns a pointer to the object named name that inherits type and with a given parent. More...

Detailed Description

Definition at line 70 of file qnetworkaccesscache_p.h.

Typedefs

NodeHash

typedef QHash<QByteArray, Node> QNetworkAccessCache::NodeHash

Definition at line 74 of file qnetworkaccesscache_p.h.

Constructors and Destructors

QNetworkAccessCache()

QNetworkAccessCache::QNetworkAccessCache

(

)

Definition at line 106 of file qnetworkaccesscache.cpp.

    : oldest(0), newest(0)
{
}

~QNetworkAccessCache()

QNetworkAccessCache::~QNetworkAccessCache

(

)

Definition at line 111 of file qnetworkaccesscache.cpp.

Referenced by QNetworkAccessCache::CacheableObject::cacheKey().

{
    clear();
}

Functions

addEntry()

void QNetworkAccessCache::addEntry	(	const QByteArray &	key,
		CacheableObject *	entry
	)

Definition at line 246 of file qnetworkaccesscache.cpp.

Referenced by QNetworkAccessCache::CacheableObject::cacheKey(), QNetworkAccessFtpBackend::open(), and QHttpThreadDelegate::startRequest().

{
    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;
}

clear()

void QNetworkAccessCache::clear

(

)

Definition at line 116 of file qnetworkaccesscache.cpp.

Referenced by QNetworkAccessCache::CacheableObject::cacheKey(), and ~QNetworkAccessCache().

{
    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;
}

emitEntryReady()

bool QNetworkAccessCache::emitEntryReady ( Node *  node, QObject *  target, const char *  member  )

private

Definition at line 212 of file qnetworkaccesscache.cpp.

Referenced by releaseEntry(), and requestEntry().

{
    if (!connect(this, SIGNAL(entryReady(QNetworkAccessCache::CacheableObject*)),
                 target, member, Qt::QueuedConnection))
        return false;

    emit entryReady(node->object);
    disconnect(SIGNAL(entryReady(QNetworkAccessCache::CacheableObject*)));

    return true;
}

entryReady

void QNetworkAccessCache::entryReady ( QNetworkAccessCache::CacheableObject *  )

signal

Referenced by QNetworkAccessCache::CacheableObject::cacheKey(), and emitEntryReady().

hasEntry()

bool QNetworkAccessCache::hasEntry

(

const QByteArray &

key

)

const

Definition at line 265 of file qnetworkaccesscache.cpp.

Referenced by QNetworkAccessCache::CacheableObject::cacheKey().

{
    return hash.contains(key);
}

linkEntry()

void QNetworkAccessCache::linkEntry ( const QByteArray &  key )

private

Appens the entry given by key to the end of the linked list.

(i.e., makes it the newest entry)

Definition at line 141 of file qnetworkaccesscache.cpp.

Referenced by releaseEntry().

{
    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;
}

releaseEntry()

void QNetworkAccessCache::releaseEntry

(

const QByteArray &

key

)

Definition at line 323 of file qnetworkaccesscache.cpp.

Referenced by QNetworkAccessCache::CacheableObject::cacheKey(), QNetworkAccessFtpBackend::disconnectFromFtp(), and QHttpThreadDelegate::startRequestSynchronously().

{
    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();
    }
}

removeEntry()

void QNetworkAccessCache::removeEntry

(

const QByteArray &

key

)

Definition at line 359 of file qnetworkaccesscache.cpp.

Referenced by QNetworkAccessCache::CacheableObject::cacheKey(), and QNetworkAccessFtpBackend::ftpDone().

{
    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);
}

requestEntry()

bool QNetworkAccessCache::requestEntry	(	const QByteArray &	key,
		QObject *	target,
		const char *	member
	)

Definition at line 270 of file qnetworkaccesscache.cpp.

Referenced by QNetworkAccessCache::CacheableObject::cacheKey(), and QNetworkAccessFtpBackend::open().

{
    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);
    }
}

requestEntryNow()

QNetworkAccessCache::CacheableObject * QNetworkAccessCache::requestEntryNow

(

const QByteArray &

key

)

Definition at line 299 of file qnetworkaccesscache.cpp.

Referenced by QNetworkAccessCache::CacheableObject::cacheKey(), and QHttpThreadDelegate::startRequest().

{
    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;
}

timerEvent()

void QNetworkAccessCache::timerEvent ( QTimerEvent *  event )

protectedvirtual

This event handler can be reimplemented in a subclass to receive timer events for the object.

QTimer provides a higher-level interface to the timer functionality, and also more general information about timers. The timer event is passed in the event parameter.

See also

startTimer(), killTimer(), event()

Reimplemented from QObject.

Definition at line 224 of file qnetworkaccesscache.cpp.

Referenced by QNetworkAccessCache::CacheableObject::cacheKey().

{
    // 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();
}

unlinkEntry()

bool QNetworkAccessCache::unlinkEntry ( const QByteArray &  key )

private

Removes the entry pointed by key from the linked list.

Returns true if the entry removed was the oldest one.

Definition at line 170 of file qnetworkaccesscache.cpp.

Referenced by addEntry(), removeEntry(), requestEntry(), and requestEntryNow().

{
    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;
}

updateTimer()

void QNetworkAccessCache::updateTimer ( )

private

Definition at line 194 of file qnetworkaccesscache.cpp.

Referenced by addEntry(), releaseEntry(), removeEntry(), requestEntry(), requestEntryNow(), and timerEvent().

{
    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);
}

Properties

hash

NodeHash QNetworkAccessCache::hash

private

Definition at line 114 of file qnetworkaccesscache_p.h.

Referenced by addEntry(), clear(), hasEntry(), linkEntry(), releaseEntry(), removeEntry(), requestEntry(), requestEntryNow(), timerEvent(), and unlinkEntry().

newest

Node* QNetworkAccessCache::newest

private

Definition at line 116 of file qnetworkaccesscache_p.h.

Referenced by clear(), linkEntry(), timerEvent(), and unlinkEntry().

oldest

Node* QNetworkAccessCache::oldest

private

Definition at line 115 of file qnetworkaccesscache_p.h.

Referenced by clear(), linkEntry(), releaseEntry(), timerEvent(), unlinkEntry(), and updateTimer().

timer

QBasicTimer QNetworkAccessCache::timer

private

Definition at line 118 of file qnetworkaccesscache_p.h.

Referenced by clear(), and updateTimer().

---

The documentation for this class was generated from the following files:

• /src/network/access/qnetworkaccesscache_p.h
• /src/network/access/qnetworkaccesscache.cpp