can it surpport POSIX rename interface now

[oucaijun]

Hi,
I am choosing aft-mtp-mount to mount my devices as a result of it's amazing speed to read/write/dir iterator.

I used QFile::rename (from Qt) to rename a file or a directory and failed! Hope to have rename API because it's a frequently used function.

step1: mount mobile with path /home/ocean/my-device/ (with mobile file transfer mode set)

$ fuse/aft-mtp-mount /home/ocean//my-device

step2: prepare an empty directory under mobile path.
mkdir -p /home/ocean//my-device/nulldfrom

step2: run the demo.
./t_rename

step3: the debug info shown us "rename nulldfrom to nulldto"

//Returns true if successful; otherwise returns false.
bool qtRename()
{
    QString src =  "nulldfrom";
    QString dest =  "nulldto";

    QString mtpDirPath = "/home/ocean/my-device/内部存储/Test";
    int status = chdir(mtpDirPath.toStdString().c_str());
    QString statusinfo = (status==0 )? "ok" : "error";
    qDebug()<<"-------- chdir " << mtpDirPath << " status ="<< statusinfo;

    //TEST QFile::rename()
    QFile from(src);
    bool ret = from.rename(dest); // failed

    //Print rename status info
    statusinfo = (ret==true )? "ok" : "error";
    qDebug()<<"-------- rename"<< src << " to "<< dest <<", status ="<< statusinfo;

    return ret;
}

I also used std::ename with the same result!

//TEST std::rename()
ret = std::rename(src.toStdString().c_str(), dest.toStdString().c_str());
ret = (ret == 0)?true:false;

//Print rename status info
statusinfo = (ret==true )? "ok" : "error";
qDebug()<<"-------- rename"<< src << " to "<< dest <<", status ="<< statusinfo;

[whoozle]

Unfortunately there's a few reasons for that:

1. I haven't seen any single android device that supports renaming in POSIX sense (e.g. setting completely new path, moving around filesystem, etc)
2. POSIX rename will not rename across filesystem boundary, so it does not always work too. Userland tools rely on error code EXDEV and do safe copy/unlink.

       EXDEV       The links named by new and old are on different file systems and the implementation does not support  links  between  file
                   systems.

So I return EXDEV to signal that copy/unlink required.

I can explore the possibility of setting "filename" property(if and only, source/destination paths are in the same directory), but I think I've tried it before and it didn't work.

[oucaijun]

Yes, I totally approval of a limitted support to rename(limit with "/", limit with directory, limit with soft link, etc). In the case of mobile devices, we can't really demand the complete rename function.

Especially in appications like filemanager, most of the renaming takes place under the same folder. If the user uses an operation that is not supported by fuse rename, it is not too late to return an error.

I know you must have implemented the rename function and I willing to try the function.

[whoozle]

fixed in 140beb4