The Q3Socket class provides a buffered TCP connection. 更多...
| 头： | #include <Q3Socket> |
| 继承： | QIODevice |
| enum | Error { ErrConnectionRefused, ErrHostNotFound, ErrSocketRead } |
| enum | State { Idle, HostLookup, Connecting, Connected, Closing } |
| Q3Socket (QObject * parent = 0, const char * name = 0) | |
| virtual | ~Q3Socket () |
| QHostAddress | address () const |
| 偏移 | at () const |
| bool | at (Offset index ) |
| void | clearPendingData () |
| virtual void | connectToHost (const QString & host , Q_UINT16 port ) |
| bool | flush () |
| int | getch () |
| bool | open (int m ) |
| QHostAddress | peerAddress () const |
| QString | peerName () const |
| Q_UINT16 | peerPort () const |
| Q_UINT16 | port () const |
| int | putch (int ch ) |
| Q_ULONG | readBufferSize () const |
| void | setReadBufferSize (Q_ULONG bufSize ) |
| virtual void | setSocket (int socket ) |
| virtual void | setSocketDevice (Q3SocketDevice * device ) |
| int | socket () const |
| Q3SocketDevice * | socketDevice () |
| 状态 | state () const |
| int | ungetch (int ch ) |
| Q_ULONG | waitForMore (int msecs , bool * timeout ) const |
| Q_ULONG | waitForMore (int msecs ) const |
| virtual bool | atEnd () const |
| virtual qint64 | bytesAvailable () const |
| virtual qint64 | bytesToWrite () const |
| virtual bool | canReadLine () const |
| virtual void | close () |
| virtual bool | open (OpenMode m ) |
| virtual Offset | size () const |
| void | bytesWritten (int nbytes ) |
| void | connected () |
| void | connectionClosed () |
| void | delayedCloseFinished () |
| void | error (int error ) |
| void | hostFound () |
| void | readyRead () |
| virtual qint64 | readData (char * data , qint64 maxlen ) |
| virtual qint64 | writeData (const char * data , qint64 len ) |
The Q3Socket class provides a buffered TCP connection.
It provides a totally non-blocking QIODevice , and modifies and extends the API of QIODevice with socket-specific code.
The functions you're likely to call most are connectToHost (), bytesAvailable (), canReadLine () and the ones it inherits from QIODevice .
connectToHost () is the most-used function. As its name implies, it opens a connection to a named host.
Most network protocols are either packet-oriented or line-oriented. canReadLine () indicates whether a connection contains an entire unread line or not, and bytesAvailable () returns the number of bytes available for reading.
The signals error (), connected (), readyRead () 和 connectionClosed () inform you of the progress of the connection. There are also some less commonly used signals. hostFound () is emitted when connectToHost () has finished its DNS lookup and is starting its TCP connection. delayedCloseFinished () is emitted when close () succeeds. bytesWritten () is emitted when Q3Socket moves data from its "to be written" queue into the TCP implementation.
There are several access functions for the socket: state () returns whether the object is idle, is doing a DNS lookup, is connecting, has an operational connection, etc. address () 和 port () return the IP address and port used for the connection. The peerAddress () 和 peerPort () functions return the IP address and port used by the peer, and peerName () returns the name of the peer (normally the name that was passed to connectToHost ()). socketDevice () returns a pointer to the Q3SocketDevice used for this socket.
Q3Socket 继承 QIODevice , and reimplements some functions. In general, you can treat it as a QIODevice for writing, and mostly also for reading. The match isn't perfect, since the QIODevice API is designed for devices that are controlled by the same machine, and an asynchronous peer-to-peer network connection isn't quite like that. For example, there is nothing that matches QIODevice::size () exactly. The documentation for open (), close (), flush (), size (), at (), atEnd (), readBlock (), writeBlock (), getch (), putch (), ungetch () 和 readLine () describes the differences in detail.
警告： Q3Socket is not suitable for use in threads. If you need to uses sockets in threads use the lower-level Q3SocketDevice 类。
另请参阅 Q3SocketDevice , QHostAddress ，和 QSocketNotifier .
This enum specifies the possible errors:
| 常量 | 值 | 描述 |
|---|---|---|
Q3Socket::ErrConnectionRefused
|
0
|
if the connection was refused |
Q3Socket::ErrHostNotFound
|
1
|
if the host was not found |
Q3Socket::ErrSocketRead
|
2
|
if a read from the socket failed |
This enum defines the connection states:
| 常量 | 值 | 描述 |
|---|---|---|
Q3Socket::Idle
|
0
|
if there is no connection |
Q3Socket::HostLookup
|
1
|
during a DNS lookup |
Q3Socket::Connecting
|
2
|
during TCP connection establishment |
Q3Socket::Connected
|
3
|
when there is an operational connection |
Q3Socket::Closing
|
4
|
if the socket is closing down, but is not yet closed. |
创建 Q3Socket object in Q3Socket::Idle 状态。
The parent and name arguments are passed on to the QObject 构造函数。
[虚拟]
Q3Socket::
~Q3Socket
()
Destroys the socket. Closes the connection if necessary.
另请参阅 close ().
Returns the host address of this socket. (This is normally the main IP address of the host, but can be e.g. 127.0.0.1 for connections to localhost.)
Returns the current read index. Since Q3Socket is a sequential device, the current read index is always zero.
这是重载函数。
Moves the read index forward to index and returns true if the operation was successful; otherwise returns false. Moving the index forward means skipping incoming data.
[虚拟]
bool
Q3Socket::
atEnd
() const
重实现自 QIODevice::atEnd ().
Returns true if there is no more data to read; otherwise returns false.
[虚拟]
qint64
Q3Socket::
bytesAvailable
() const
重实现自 QIODevice::bytesAvailable ().
Returns the number of incoming bytes that can be read, i.e. the size of the input buffer. Equivalent to size ().
另请参阅 bytesToWrite ().
[虚拟]
qint64
Q3Socket::
bytesToWrite
() const
重实现自 QIODevice::bytesToWrite ().
Returns the number of bytes that are waiting to be written, i.e. the size of the output buffer.
另请参阅 bytesAvailable () 和 clearPendingData ().
[signal]
void
Q3Socket::
bytesWritten
(
int
nbytes
)
This signal is emitted when data has been written to the network. The nbytes parameter specifies how many bytes were written.
The bytesToWrite () function is often used in the same context; it indicates how many buffered bytes there are left to write.
另请参阅 writeBlock () 和 bytesToWrite ().
[虚拟]
bool
Q3Socket::
canReadLine
() const
重实现自 QIODevice::canReadLine ().
Returns true if it's possible to read an entire line of text from this socket at this time; otherwise returns false.
Note that if the peer closes the connection unexpectedly, this function returns false. This means that loops such as this won't work:
while( !socket->canReadLine() ) // WRONG ;
另请参阅 readLine ().
Deletes the data that is waiting to be written. This is useful if you want to close the socket without waiting for all the data to be written.
另请参阅 bytesToWrite (), close ()，和 delayedCloseFinished ().
[虚拟]
void
Q3Socket::
close
()
重实现自 QIODevice::close ().
Closes the socket.
The read buffer is cleared.
If the output buffer is empty, the state is set to
Q3Socket::Idle
and the connection is terminated immediately. If the output buffer still contains data to be written,
Q3Socket
goes into the
Q3Socket::Closing
state and the rest of the data will be written. When all of the outgoing data have been written, the state is set to
Q3Socket::Idle
and the connection is terminated. At this point, the
delayedCloseFinished
() 信号发射。
If you don't want that the data of the output buffer is written, call clearPendingData () before you call close().
另请参阅 state (), bytesToWrite ()，和 clearPendingData ().
[虚拟]
void
Q3Socket::
connectToHost
(const
QString
&
host
,
Q_UINT16
port
)
试图连接到 host on the specified port and return immediately.
Any connection or pending connection is closed immediately, and
Q3Socket
goes into the
HostLookup
state. When the lookup succeeds, it emits
hostFound
(), starts a TCP connection and goes into the
Connecting
state. Finally, when the connection succeeds, it emits
connected
() and goes into the
Connected
state. If there is an error at any point, it emits
error
().
host may be an IP address in string form, or it may be a DNS name. Q3Socket will do a normal DNS lookup if required. Note that port is in native byte order, unlike some other libraries.
另请参阅 state ().
[signal]
void
Q3Socket::
connected
()
此信号发射后于 connectToHost () 有被调用且连接已成功建立。
另请参阅 connectToHost () 和 connectionClosed ().
[signal]
void
Q3Socket::
connectionClosed
()
This signal is emitted when the other end has closed the connection. The read buffers may contain buffered input data which you can read after the connection was closed.
另请参阅 connectToHost () 和 close ().
[signal]
void
Q3Socket::
delayedCloseFinished
()
This signal is emitted when a delayed close is finished.
若调用 close () and there is buffered output data to be written, Q3Socket goes into the Q3Socket::Closing state and returns immediately. It will then keep writing to the socket until all the data has been written. Then, the delayedCloseFinished() signal is emitted.
另请参阅 close ().
[signal]
void
Q3Socket::
error
(
int
error
)
此信号发射，在发生错误后。 error parameter is the Error 值。
Implementation of the abstract virtual QIODevice::flush() function. This function always returns true.
Reads a single byte/character from the internal read buffer. Returns the byte/character read, or -1 if there is nothing to be read.
另请参阅 bytesAvailable () 和 putch ().
[signal]
void
Q3Socket::
hostFound
()
此信号发射后于 connectToHost () 有被调用且主机查找成功时。
另请参阅 connected ().
[虚拟]
bool
Q3Socket::
open
(
OpenMode
m
)
重实现自 QIODevice::open ().
Opens the socket using the specified QIODevice file mode m . This function is called automatically when needed and you should not call it yourself.
另请参阅 close ().
这是重载函数。
Returns the address of the connected peer if the socket is in Connected state; otherwise an empty QHostAddress 被返回。
Returns the host name as specified to the connectToHost () function. An empty string is returned if none has been set.
Returns the peer's host port number, normally as specified to the connectToHost () function. If none has been set, this function returns 0.
Note that Qt always uses native byte order, i.e. 67 is 67 in Qt; there is no need to call htons().
Returns the host port number of this socket, in native byte order.
写入字符 ch to the output buffer.
返回 ch , or -1 if an error occurred.
另请参阅 getch ().
Returns the size of the read buffer.
另请参阅 setReadBufferSize ().
[virtual protected]
qint64
Q3Socket::
readData
(
char
*
data
,
qint64
maxlen
)
重实现自 QIODevice::readData ().
读取 maxlen bytes from the socket into data and returns the number of bytes read. Returns -1 if an error occurred.
[signal]
void
Q3Socket::
readyRead
()
This signal is emitted every time there is new incoming data.
Bear in mind that new incoming data is only reported once; if you do not read all the data, this class buffers the data and you can read it later, but no signal is emitted unless new data arrives. A good practice is to read all data in the slot connected to this signal unless you are sure that you need to receive more data to be able to process it.
另请参阅 readBlock (), readLine ()，和 bytesAvailable ().
Sets the size of the Q3Socket 's internal read buffer to bufSize .
Usually Q3Socket reads all data that is available from the operating system's socket. If the buffer size is limited to a certain size, this means that the Q3Socket class doesn't buffer more than this size of data.
If the size of the read buffer is 0, the read buffer is unlimited and all incoming data is buffered. This is the default.
If you read the data in the readyRead () signal, you shouldn't use this option since it might slow down your program unnecessary. This option is useful if you only need to read the data at certain points in time, like in a realtime streaming application.
另请参阅 readBufferSize ().
[虚拟]
void
Q3Socket::
setSocket
(
int
socket
)
Sets the socket to use
socket
和
state
() 到
Connected
. The socket must already be connected.
This allows us to use the Q3Socket class as a wrapper for other socket types (e.g. Unix Domain Sockets).
另请参阅 socket ().
[虚拟]
void
Q3Socket::
setSocketDevice
(
Q3SocketDevice
*
device
)
Sets the internal socket device to device . Passing a device of 0 will cause the internal socket device to be used. Any existing connection will be disconnected before using the new device .
The new device should not be connected before being associated with a Q3Socket ; after setting the socket call connectToHost () to make the connection.
This function is useful if you need to subclass Q3SocketDevice and want to use the Q3Socket API, for example, to implement Unix domain sockets.
另请参阅 socketDevice ().
[虚拟]
偏移
Q3Socket::
size
() const
重实现自 QIODevice::size ().
Returns the number of incoming bytes that can be read right now (like bytesAvailable ()).
Returns the socket number, or -1 if there is no socket at the moment.
另请参阅 setSocket ().
Returns a pointer to the internal socket device.
There is normally no need to manipulate the socket device directly since this class does the necessary setup for most applications.
另请参阅 setSocketDevice ().
Returns the current state of the socket connection.
另请参阅 Q3Socket::State .
This implementation of the virtual function QIODevice::ungetch () prepends the character ch to the read buffer so that the next read returns this character as the first character of the output.
Wait up to msecs milliseconds for more data to be available.
若 msecs is -1 the call will block indefinitely.
Returns the number of bytes available.
若 timeout is non-null and no error occurred (i.e. it does not return -1): this function sets * timeout to true, if the reason for returning was that the timeout was reached; otherwise it sets * timeout to false. This is useful to find out if the peer closed the connection.
警告： This is a blocking call and should be avoided in event driven applications.
另请参阅 bytesAvailable ().
这是重载函数。
[virtual protected]
qint64
Q3Socket::
writeData
(const
char
*
data
,
qint64
len
)
重实现自 QIODevice::writeData ().
写入 len bytes to the socket from data and returns the number of bytes written. Returns -1 if an error occurred.