Qt multithreaded copying files QFile: : copy () a strange question-CodePudding

I want to use the production consumption patterns, multithreaded copying files, using a static method QFile: : copy ()
Perform half would collapse, only copy the part of
If I were in QFile: : copy () the following add qDebug () & lt; <"Hello"; , that is, consumer, CPP line 24, will not collapse

 
QFile: : copy (SRC, DST); 
QDebug () & lt; <"Hello";

What reason is this?

Producer. H

 

Struct MoveInfo {
Bool rm. 
QString SRC. 
QString DST. 
}; 

Enum TAG {
COUNT_FILE=0, 
HANDLE=1, 
}; 

The static QSemaphore freeSpace (8);//control task queue length of buffer 
The static QSemaphore usedSpace (0); 
The static QQueue Task_q; 


The class Producer: public QThread 
{
Q_OBJECT 

Public: 
Producer (parent QObject *=nullptr); 
~ Producer (); 

Void the run (); 
Void setParams (QString, QString, bool); 

Signals: 
Void mainMsgChanged (QString, QColor c=Qt: : black); 
Void subMsgChanged (QString); 
Void completed (); 

Private: 
QString root_path; 
Int total=0; 
Int count=0; 
QString src_path; 
QString dst_path; 
Bool rm. 
Void walkPath (QString, QString, TAG); 
};

Producer. The CPP

 

Producer: : Producer (QObject * parent) 
: QThread (parent) 
{

} 

Void Producer: : run () 
{
QDebug (). Noquote () & lt; <"The Source path:" & lt; Total=0; 
count=0; 
Emit mainMsgChanged (tr (" are statistical number... ")); 
WalkPath (src_path, dst_path, TAG: : COUNT_FILE); 
QDebug (). Noquote () & lt; <"The Total number of files:" & lt; count=0; 
Emit mainMsgChanged (tr (" being processed... ")); 
WalkPath (src_path, dst_path, TAG: : HANDLE). 
Emit mainMsgChanged (tr (" Ready ")); 

If (total!=0) 
Emit subMsgChanged (QString (" [1%] % % % 2/3 "). Arg (int (100 * ((float) count/total))). Arg (count). Arg (total)); 
The else 
Emit subMsgChanged (QString (" [1%] % % % 2/3 "). Arg (100). Arg (count). Arg (total)); 

//no more documents, inform the consumer thread exit into the empty 
MoveInfo info; 
for (int i=0; i <8; I++) 
{
FreeSpace. Acquire (); 
Task_q. The enqueue (info); 
UsedSpace. Release (); 
} 
} 

Void Producer: : walkPath (QString SRC, QString DST, the TAG t) 
{
The QDir src_dir (SRC); 
The QDir dst_dir (DST); 
QFileInfoList src_files=src_dir. EntryInfoList (QStringList {" *. XLS "}, QDir: : Files | QDir: : NoDotAndDotDot); 
MoveInfo info; 

If (t==TAG: : COUNT_FILE) 
Emit subMsgChanged (QDir: : toNativeSeparators (SRC));//notification interface in the current directory 

For (auto file: src_files) 
{
If (t==TAG: : COUNT_FILE)//statistical file first total 
{
Total++; 
} else {
The info. The rm=rm; 
Info. SRC=https://bbs.csdn.net/topics/file.filePath (); 
Info. DST=dst_dir. FilePath (file. The fileName ()); 
FreeSpace. Acquire (); 
Task_q. The enqueue (info);//the file information into queue 
UsedSpace. Release (); 
count++; 
//notification interface update progress 
Emit subMsgChanged (QString (" [1%] % % % 2/3 "). Arg (int (100 * ((float) count/total))). Arg (count). Arg (total)); 
} 
} 
QStringList src_dirs=src_dir. EntryList (QStringList {}, QDir: : Dirs | QDir: : NoDotAndDotDot); 

//recursive processing all subdirectories 
For (auto sd: src_dirs) 
{
if(! Dst_dir. The exists (sd) & amp; & T==TAG: : HANDLE) 
Dst_dir. Mkdir (sd); 
WalkPath (src_dir filePath (sd), dst_dir. FilePath (sd), t); 
} 
} 

Producer: : ~ Producer () 
{

}

Consumer. H consumers

 

The class Consumer: public QThread 
{
Q_OBJECT 
Public: 
Consumer (parent QObject *=nullptr); 
~ Consumer (); 
Void the run (); 
};

Consumer. CPP consumers

 

Consumer: : Consumer (QObject * parent) 
: QThread (parent) 
{

} 

Void Consumer: : run () 
{
MoveInfo info; 
QDebug () & lt; 
While (true) 
{
UsedSpace. Acquire (); 
Info=task_q. Dequeue ();//get a file information 
FreeSpace. Release (); 

If (info. SRC. IsEmpty ())//if the file is called an empty, interruption, an end to 
break; 

if(! QFileInfo: : the exists (info. DST)) 
{
QFile: : copy (info. SRC, info. DST); 
QDebug () & lt; } 

If (info. Rm) 
QFile: : remove (info. SRC); 
} 
} 

Consumer: : ~ Consumer () 
{

}

 
Void MainWindow: : start () 
{
MProducer. SetParams (" D:/files ", "D:/target/", false); 
MProducer - & gt; Start (). 
for (int i=0; i <8; I++) 
{
Consumer * c=new Consumer (); 
The connect (c, & amp; Consumer: : finished, c, & amp; Consumer: : deleteLater); 
C - & gt; Start (). 
} 
}