Re: [darcs-devel] Re: darcs patch: Windows hard link support
Simon, Looking further at your patch, I'm not quite sure whether you're looking at the right place. Please forgive me if the below is obvious for you. There are two places where Darcs will create hard links: (1) when doing``darcs get'' on a local filesystem, and (2) when runninng ``darcs optimize --relink''. The function maybe_relink, which is the one you tried to patch, is only used by (2). Now (1) is implemented differently: it calls copyFilesOrUrls, which in turn calls copyLocals, which in turn calls copyLocal which is in External.hs and is implemented as so: copyLocal fou out = createLink fou out `catchall` cloneFile fou out cloneFile source dest = readFilePS source >>= writeFilePS dest So in order to get hard links on Windows when doing ``darcs get'', you've got two solutions -- you can either implement System.Posix.Files.createLink on Windows within the Ghc libraries (surely the preferred solution), or provide us with an implentation of createLink that works under Windows and that we'll substitute for Ghc's version within Darcs. (In case you find yourself confused by the package structure: there's an extra indirection through a module ``Workaround'' which is generated by configure.) Juliusz ___ darcs-devel mailing list darcs-devel@darcs.net http://www.abridgegame.org/cgi-bin/mailman/listinfo/darcs-devel
RE: [darcs-devel] Re: darcs patch: Windows hard link support
Juliusz Chroboczek wrote: > Looking further at your patch, I'm not quite sure whether you're > looking at the right place. Please forgive me if the below is > obvious for you. > > There are two places where Darcs will create hard links: (1) when > doing``darcs get'' on a local filesystem, and (2) when runninng > ``darcs optimize --relink''. > > The function maybe_relink, which is the one you tried to patch, is > only used by (2). Now (1) is implemented differently: it calls > copyFilesOrUrls, which in turn calls copyLocals, which in turn calls > copyLocal which is in External.hs and is implemented as so: > > copyLocal fou out = createLink fou out `catchall` cloneFile fou out > > cloneFile source dest = readFilePS source >>= writeFilePS dest > > So in order to get hard links on Windows when doing ``darcs get'', > you've got two solutions -- you can either implement > System.Posix.Files.createLink on Windows within the Ghc libraries > (surely the preferred solution), or provide us with an implentation of > createLink that works under Windows and that we'll substitute for > Ghc's version within Darcs. > > (In case you find yourself confused by the package structure: there's > an extra indirection through a module ``Workaround'' which is > generated by configure.) Thanks Juliusz - actually I did realise this after I submitted the patch. One reason for the confusion was that I timed a 'darcs get' from a local repo using my installed darcs against the newly built one, and the new one was much faster, so I declared success :-) I guess the speedup must be due to something else - maybe the System.Process switch that was also in my local copy. Cheers, Simon ___ darcs-devel mailing list darcs-devel@darcs.net http://www.abridgegame.org/cgi-bin/mailman/listinfo/darcs-devel
Re: [darcs-devel] Re: darcs patch: Windows hard link support
> >I don't understand Windows -- but that looks completely bogus to me. > >Does it obey the description in the comment just below? > > Er. Ok, I completely failed to understand what maybe_relink() was supposed > to do, and didn't notice that it should compare the files before attempting > to link. Sorry about that, please ignore the patch, maybe I'll submit a > fixed one at some point. Thanks for watching carefully, Juliusz. I have rolled this patch back. Argh... sorry about that, everybody. My lessons are to read surronding code more carefully, watch for suspicious stuff like the Windows code being so much shorter that the Unix stuff, and pay close attention to inner nuts and bolts. Simon: Please note that you'll probably want to pull in both your patch and the rollback before submitting a new one. Juliusz: Will you be able to advise on any new patches on this? I definitely plan on moving with much more care on this code. -- Eric Kow http://www.loria.fr/~kow PGP Key ID: 08AC04F9 Merci de corriger mon français. pgpKvTnT1NaC6.pgp Description: PGP signature ___ darcs-devel mailing list darcs-devel@darcs.net http://www.abridgegame.org/cgi-bin/mailman/listinfo/darcs-devel
[darcs-devel] Re: darcs patch: Windows hard link support
Juliusz Chroboczek wrote: +#define _WIN32_WINNT 0x0500 +#include hunk ./maybe_relink.c 39 -return 0; +BOOL result; +result = CreateHardLink(src, dst, NULL); +if (!result) +return 0; +else +return -2; } I don't understand Windows -- but that looks completely bogus to me. Does it obey the description in the comment just below? Er. Ok, I completely failed to understand what maybe_relink() was supposed to do, and didn't notice that it should compare the files before attempting to link. Sorry about that, please ignore the patch, maybe I'll submit a fixed one at some point. Cheers, Simon ___ darcs-devel mailing list darcs-devel@darcs.net http://www.abridgegame.org/cgi-bin/mailman/listinfo/darcs-devel
