Qt实现Kermit协议(四)

3 实现

3.3 KermitRecvFile

该模块实现了Kermit接收文件功能。

序列图如下：

3.3.1 KermitRecvFile定义

class QSerialPort;
class KermitRecvFile : public QObject, public Kermit
{Q_OBJECT
public:explicit KermitRecvFile(QSerialPort *serial, QObject *parent = nullptr);public slots:void start(QString const& fileName);void stop();void cancel();signals:void gotFileSize(quint64 filesize);void progressInfo(quint32 blockNumber, quint64 bytesOfSend);void error(QString const& e);void finished();
protected:int write(char const *data, int size) override;int read(char *data, int size) override;char getc() override;void on_init(int seq, const char* data, int size) override;void on_data(int seq, const char* data, int size) override;void on_break(int seq, const char* data, int size) override;
private:void saveData(const char* data, int size);bool singled() { return signal_; }void doSignal() { signal_ = true; };
private:QSerialPort* serial_;volatile bool signal_;State state_ = SSNUL;QFile file_;int timeMs = 0;quint32 blockNumber = 0;quint64 bytesOfRecv_ = 0;};

公共接口：

start 开始接收文件
stop 停止传输文件
cancel 中断传输文件

信号：

gotFileSize 文件大小信号
progressInfo 传输进度信号
error 出错信号
finished 传输结束信号

重载接口:

on_init 处理开始包
on_data 处理数据包
on_break 处理中断包
write 向串口写数据
read 从串口读数据
getc 从串口读取一个字符

其它接口:

saveData 解码数据并保存

3.3.2 KermitRecvFile实现

3.3.2.1 start/stop/cancel

void KermitRecvFile::start(QString const& fileName)
{file_.setFileName(fileName);while(!singled() && state_ != SSBRK)recv_packet();emit finished();serial_->moveToThread(QApplication::instance()->thread());
}void KermitRecvFile::stop() { doSignal(); }void KermitRecvFile::cancel() { state_ = SSBRK; }

函数说明:

start
- 循环接收数据包，直到收到停止或终止信号
- 发送结束信号
stop 发送停止信号
cancel 设置终止信号

3.3.2.2 on_init/on_data/on_break

void KermitRecvFile::on_init(int seq, const char* data, int size)
{Kermit::on_init(seq, data, size);state_ = SSINT;
}void KermitRecvFile::on_data(int seq, const char* data, int size)
{Q_UNUSED(seq)if(state_ == SSINT){file_.open(QIODevice::WriteOnly);state_ = SSDAT;}if(file_.isOpen()){saveData(data, size);send_ack(seq);}
}void KermitRecvFile::on_break(int seq, const char* data, int size)
{Q_UNUSED(seq)Q_UNUSED(data)Q_UNUSED(size)state_ = SSBRK;
}

函数说明:

on_init 处理开始包，设置状态为初始
on_data
- 如果是初始状态，则打开文件，将状态设置为接收数据状态
- 保存数据
on_break 设置状态为中断

3.2.2.3 write/read/getc/saveData

int KermitRecvFile::write(char const *data, int size) {return serial_->write(data, size);
}int KermitRecvFile::read(char *data, int size)
{int read_size = 0;while(!singled() && read_size < size){if(serial_->waitForReadyRead(timeMs))read_size += serial_->read(data + read_size, size - read_size);}return read_size;
}char KermitRecvFile::getc()
{char c = NUL;while(!singled()){if(serial_->waitForReadyRead(timeMs)){serial_->getChar(&c);break;}}return c;
}void KermitRecvFile::saveData(const char* data, int size)
{char d[MaxLen];char a;int index = 0;int recvSize = 0;while(index < size){index += decode(data + index, a);d[recvSize++] = a;}file_.write(d, recvSize);blockNumber++;bytesOfRecv_ += recvSize;emit progressInfo(blockNumber, bytesOfRecv_);
}