c++ - Qt:QSslSocket::bytesWritten() 信号发射太频繁

Question

我使用此代码通过套接字传输大文件内存使用量没有峰值:

    connect(socket, SIGNAL(bytesWritten(qint64)), this, SLOT(refillSocketBuffer(qint64)));
    refillSocketBuffer(128*1024);
}

void FtpRetrCommand::refillSocketBuffer(qint64 bytes)
{
    if (!file->atEnd()) {
        socket->write(file->read(bytes));
    } else {
        socket->disconnectFromHost();
    }
}

这适用于 QTcpSocket，但是对于加密的 QSslSocket，bytesWritten() 信号不断发出，这导致我的函数一直写入套接字，比它通过套接字发送数据快得多，所以最终它的内存使用量达到 400 MB，操作系统将其杀死。

Answer 1

我只是在进一步挖掘后找到了答案，它实际上在文档中。看来我应该为 SSL 套接字使用 encryptedBytesWritten():

Note: Be aware of the difference between the bytesWritten() signal and the encryptedBytesWritten() signal. For a QTcpSocket, bytesWritten() will get emitted as soon as data has been written to the TCP socket. For a QSslSocket, bytesWritten() will get emitted when the data is being encrypted and encryptedBytesWritten() will get emitted as soon as data has been written to the TCP socket.

所以我需要更改这段代码:

connect(socket, SIGNAL(bytesWritten(qint64)), this, SLOT(refillSocketBuffer(qint64)));

为此:

if (socket->isEncrypted()) {
    connect(socket, SIGNAL(encryptedBytesWritten(qint64)), this, SLOT(refillSocketBuffer(qint64)));
} else {
    connect(socket, SIGNAL(bytesWritten(qint64)), this, SLOT(refillSocketBuffer(qint64)));
}