The QAbstractNetworkCache class provides the interface for cache implementations. 更多...
| 头： | #include <QAbstractNetworkCache> |
| qmake: | QT += network |
| Since: | Qt 4.5 |
| 继承： | QObject |
| 继承者： | QNetworkDiskCache |
| virtual | ~QAbstractNetworkCache () |
| virtual qint64 | cacheSize () const = 0 |
| virtual QIODevice * | data (const QUrl & url ) = 0 |
| virtual void | insert (QIODevice * device ) = 0 |
| virtual QNetworkCacheMetaData | metaData (const QUrl & url ) = 0 |
| virtual QIODevice * | prepare (const QNetworkCacheMetaData & metaData ) = 0 |
| virtual bool | remove (const QUrl & url ) = 0 |
| virtual void | updateMetaData (const QNetworkCacheMetaData & metaData ) = 0 |
| virtual void | clear () = 0 |
| const QMetaObject | staticMetaObject |
| QAbstractNetworkCache (QObject * parent = nullptr) |
The QAbstractNetworkCache class provides the interface for cache implementations.
QAbstractNetworkCache is the base class for every standard cache that is used by QNetworkAccessManager . QAbstractNetworkCache is an abstract class and cannot be instantiated.
另请参阅 QNetworkDiskCache .
[protected]
QAbstractNetworkCache::
QAbstractNetworkCache
(
QObject
*
parent
= nullptr)
构造抽象网络缓存采用给定 parent .
[虚拟]
QAbstractNetworkCache::
~QAbstractNetworkCache
()
销毁缓存。
Any operations that have not been inserted are discarded.
另请参阅 insert ().
[pure virtual]
qint64
QAbstractNetworkCache::
cacheSize
() const
Returns the current size taken up by the cache. Depending upon the cache implementation this might be disk or memory size.
在基类中，这是纯虚函数。
另请参阅 clear ().
[pure virtual slot]
void
QAbstractNetworkCache::
clear
()
Removes all items from the cache. Unless there was failures clearing the cache cacheSize () should return 0 after a call to clear.
在基类中，这是纯虚函数。
另请参阅 cacheSize () 和 remove ().
[pure virtual]
QIODevice
*QAbstractNetworkCache::
data
(const
QUrl
&
url
)
返回的数据关联 url .
It is up to the application that requests the data to delete the QIODevice when done with it.
If there is no cache for url , the url is invalid, or if there is an internal cache error 0 is returned.
在基类中，这是纯虚函数。
另请参阅 metaData () 和 prepare ().
[pure virtual]
void
QAbstractNetworkCache::
insert
(
QIODevice
*
device
)
Inserts the data in device and the prepared meta data into the cache. After this function is called the data and meta data should be retrievable using data () 和 metaData ().
To cancel a prepared inserted call remove () on the metadata's url.
在基类中，这是纯虚函数。
[pure virtual]
QNetworkCacheMetaData
QAbstractNetworkCache::
metaData
(const
QUrl
&
url
)
返回元数据为 URL url .
If the url is valid and the cache contains the data for url, a valid QNetworkCacheMetaData 被返回。
在基类中，这是纯虚函数。
另请参阅 updateMetaData () 和 data ().
[pure virtual]
QIODevice
*QAbstractNetworkCache::
prepare
(const
QNetworkCacheMetaData
&
metaData
)
Returns the device that should be populated with the data for the cache item metaData . When all of the data has been written insert () should be called. If metaData is invalid or the url in the metadata is invalid 0 is returned.
The cache owns the device and will take care of deleting it when it is inserted or removed.
To cancel a prepared inserted call remove () on the metadata's url.
在基类中，这是纯虚函数。
另请参阅 remove (), updateMetaData ()，和 insert ().
[pure virtual]
bool
QAbstractNetworkCache::
remove
(const
QUrl
&
url
)
Removes the cache entry for url , returning true if success otherwise false.
在基类中，这是纯虚函数。
[pure virtual]
void
QAbstractNetworkCache::
updateMetaData
(const
QNetworkCacheMetaData
&
metaData
)
Updates the cache meta date for the metaData 's url to metaData
If the cache does not contains a cache item for the url then no action is taken.
在基类中，这是纯虚函数。