Re: [Bug-wget] [PATCH] Implement --keep-badhash to keep Metalink's files with a bad hash

[Matthew White]

On Thu, 04 Aug 2016 12:08:50 +0200
Tim Ruehsen <address@hidden> wrote:

> On Wednesday, August 3, 2016 2:40:14 PM CEST Matthew White wrote:
> > On Wed, 03 Aug 2016 14:05:06 +0200
> > 
> > Tim Ruehsen <address@hidden> wrote:
> > > On Tuesday, August 2, 2016 11:27:28 AM CEST Matthew White wrote:
> > > > On Mon, 01 Aug 2016 16:32:30 +0200
> > > > 
> > > > Tim Ruehsen <address@hidden> wrote:
> > > > > On Saturday, July 30, 2016 9:41:48 PM CEST Matthew White wrote:
> > > > > > Hello!
> > > > > > 
> > > > > > I think that sometimes it could help to keep downloaded Metalink's
> > > > > > files
> > > > > > which have a bad hash.
> > > > > > 
> > > > > > The default wget behaviour is to delete such files.
> > > > > > 
> > > > > > This patch provides a way to keep files which have a bad hash
> > > > > > through
> > > > > > the
> > > > > > option --keep-badhash. It appends the suffix .badhash to the file
> > > > > > name,
> > > > > > except without overwriting existing files. In the latter case, an
> > > > > > unique
> > > > > > suffix is appended after .badhash.
> > > > > > 
> > > > > > I made this patch working on the following branch:
> > > > > > master (latest 20cac2c5ab3d63aacfba35fb10878a2d490e2377)
> > > > > > git://git.savannah.gnu.org/wget.git
> > > > > > 
> > > > > > What do you think?
> > > > > 
> > > > > Hi Matthew,
> > > > > 
> > > > > good work !
> > > > > 
> > > > > While your FSF assignment is underway (PM), we can continue polishing.
> > > > > 
> > > > > Didn't test your code yet,  but from what I see, there are just these
> > > > > peanuts:
> > > > > 
> > > > > 1.
> > > > > +  bhash = malloc (strlen (name) + strlen (".badhash") + 1);
> > > > > +  strcat (strcpy (bhash, name), ".badhash");
> > > > > 
> > > > > Please consider using concat_strings() from util.h.
> > > > > And please leave an empty line between var declaration and code - just
> > > > > for
> > > > > readability.
> > > > > 
> > > > > 2.
> > > > > Please add 'link' and 'unlink' to bootstrap.conf. Gnulib will emulate
> > > > > these on platforms where they are not available (or have a slightly
> > > > > different behavior). I guess we simply forgot 'unlink' when we
> > > > > switched
> > > > > to gnulib.
> > > > > 
> > > > > 3.
> > > > > The (GNU) commit messages should ideally look like:
> > > > > 
> > > > > one line of short description
> > > > > <empty line>
> > > > > file changes
> > > > > <empty line>
> > > > > long description
> > > > > 
> > > > > For example:
> > > > > Add new option --keep-badhash
> > > > > 
> > > > > * src/init.c: Add keepbadhash
> > > > > * src/main.c: Add keep-badhash
> > > > > * src/options.h: Add keep_badhash
> > > > > * doc/wget.texi: Add docs for --keep-badhash
> > > > > * src/metalink.h: Add prototypes badhash_suffix(), badhash_or_remove()
> > > > > * src/metalink.c: New functions badhash_suffix(), badhash_or_remove().
> > > > > 
> > > > >   (retrieve_from_metalink): Call append .badhash()
> > > > > 
> > > > > With --keep-badhash, append .badhash to Metalink's files with checksum
> > > > > mismatch, except without overwriting existing files.
> > > > > 
> > > > > Without --keep-badhash, remove downloaded files with checksum mismatch
> > > > > (this conforms to the old behaviour).
> > > > > 
> > > > > [This also applies to to your other patches]
> > > > > 
> > > > > 4.
> > > > > Please not only write 'keepbadhash', but also what you did (e.g.
> > > > > remove,
> > > > > rename, add, ...), see my example above.
> > > > > 
> > > > > Those ChangeLog entries should allow finding changes / faults /
> > > > > regressions
> > > > > etc. even when a versioning system is not at hand, e.g. when unpacking
> > > > > the
> > > > > sources from a tarball. (Not debatable that consulting commit messages
> > > > > directly is much more powerful.)
> > > > > 
> > > > > 5.
> > > > > You write "except without overwriting existing files", maybe you
> > > > > should
> > > > > mention appending a counter instead of overwriting existent files !?
> > > > > 
> > > > > 
> > > > > Regards, Tim
> > > > 
> > > > Thanks Tim!
> > > > 
> > > > I really needed your guidance. I sent the modified patches to
> > > > address@hidden
> > > > 
> > > > I believe there are more things to fix.
> > > > 
> > > > Consider the following after applying the attached patch:
> > > > * src/metalink.c (retrieve_from_metalink): line 124: If the download is
> > > > interrupted (output_stream isn't NULL), and there are more urls for the
> > > > same file (we are still in the download loop), switching to the next url
> > > > should resume the download (instead than start it over).
> > > > 
> > > > In this patch I added a fix to rename/remove the fully downloaded file
> > > > (output_stream is NULL), but there was an error (probably checksum) and
> > > > we
> > > > are still in the download loop (more urls for the same file). But as
> > > > said
> > > > before, switching to the next url should continue the download: *
> > > > src/metalink.c (retrieve_from_metalink): line 131: Rename/remove fully
> > > > downloaded file on error
> > > > 
> > > > I still have to investigate the problem...
> > > 
> > > So, I wait with 0001-... !?
> > > 
> > > 0002-... has been pushed (extended with 'symlink').
> > > 
> > > Thanks for your contribution.
> > > 
> > > Tim
> > 
> > Ok for 0002. Thanks.
> > 
> > There's no problem applying the 0001.
> 
> Applied and pushed !
> 
> > The "if the stream got interrupted, then restart the download with the next
> > url" (output_stream isn't NULL) was already there before the patch 0001.
> > 
> > [debug is required to know when output_stream isn't NULL]
> > 
> > commit 7fad76db4cdb7a0fe7e5aa0dd88f5faaf8f4cdc8
> > * src/metalink.c (retrieve_from_metalink): line 124: 'if (output_stream)'
> > remove file and restart download with next url
> > 
> > With the 0001, if --keep-badhash is used the file is renamed instead than
> > removed, even when "output_stream is NULL".
> > 
> > I have to look through the "stream interrupted" situation.
> > 
> > I'm guessing that the download is not resumed.
> > 
> > What do you suggest?
> 
> We need a  document where we define wanted behavior, create tests and amend 
> the 
> code.
> 
> Regards, Tim

Ok, I just documented a test. See the attached tarball.

Also there is a patch attached (there's a copy in the tarball too), providing 
the suggested bugfix.

Let me know,
Matthew

-- 
Matthew White <address@hidden>

Bugfix-Continue-download-when-retrying-with-the-next.patch
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Bugfix-Continue-download-when-retrying-with-the-next.d.tar.xz
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