> On 2 Mar 2022, at 13:40, Davis, Matthew via Python-ideas > <python-ideas@python.org> wrote: > > > Hi, > > Currently shutil.copyfileobj returns nothing. > I would like to be able to find out how many bytes were copied. > > Whilst most file-like objects have a .tell() which you could use, some don’t, > and .tell() is not guaranteed to measure the number of bytes, it could > measure with other units.
Can you use os.fstat() on one of the file objects? Can you write a helper that gets the size from the object that do not have tell()? Barry > > I don’t think changing the return value from None to not-None would be > backwards incompatible. > > We could also do the same change for all other shutil.copy* methods (except > copytree). > > Looking at the code, this seems straightforward to implement. > > Existing code: > > ``` > def copyfileobj(fsrc, fdst, length=0): > """copy data from file-like object fsrc to file-like object fdst""" > # Localize variable access to minimize overhead. > if not length: > length = COPY_BUFSIZE > fsrc_read = fsrc.read > fdst_write = fdst.write > while True: > buf = fsrc_read(length) > if not buf: > break > fdst_write(buf) > ``` > > New code: > > > ``` > def copyfileobj(fsrc, fdst, length=0): > """copy data from file-like object fsrc to file-like object fdst""" > # Localize variable access to minimize overhead. > if not length: > length = COPY_BUFSIZE > fsrc_read = fsrc.read > fdst_write = fdst.write > bytes_copied = 0 > while True: > buf = fsrc_read(length) > if not buf: > break > fdst_write(buf) > bytes_copied += len(buf) > return bytes_copied > ``` > > Regards, > Matt > > > Matthew Davis > Data Analytics Senior Lead > Telstra Energy – Decision Science & AI > E: matthew.davi...@team.telstra.com | M: 0415762868 > > > > _______________________________________________ > Python-ideas mailing list -- python-ideas@python.org > To unsubscribe send an email to python-ideas-le...@python.org > https://mail.python.org/mailman3/lists/python-ideas.python.org/ > Message archived at > https://mail.python.org/archives/list/python-ideas@python.org/message/ZKVI4DE7RLYQNLV3XYUUW24FOO57WB5P/ > Code of Conduct: http://python.org/psf/codeofconduct/
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