# [PATCH] import-tars: support hard links 3 messages from 2016-08-03 to 2016-08-04. Participants: Johannes Schindelin, Junio C Hamano. Thread: https://gitlist.dev/t/42995 ## Johannes Schindelin, 2016-08-03 13:30 Subject: [PATCH] import-tars: support hard links Message-ID: URL: https://gitlist.dev/e/bb3b91403fae1964aa990fc16fd8a4e5f16885e6.1470230877.git.johannes.schindelin%40gmx.de ``` Previously, we simply treated hard links as if they were plain files with size 0, ignoring the link type "1" and hence the link target. What we should do instead, of course, is to use the link target to get at the import mark for the contents, even if we cannot recreate the hard link per se, as Git has no concept of hard links. Signed-off-by: Johannes Schindelin --- Published-As: https://github.com/dscho/git/releases/tag/import-tars-hardlink-v1 contrib/fast-import/import-tars.perl | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) diff --git a/contrib/fast-import/import-tars.perl b/contrib/fast-import/import-tars.perl index 95438e1..d60b431 100755 --- a/contrib/fast-import/import-tars.perl +++ b/contrib/fast-import/import-tars.perl @@ -96,18 +96,21 @@ foreach my $tar_file (@ARGV) $mtime = oct $mtime; next if $typeflag == 5; # directory - print FI "blob\n", "mark :$next_mark\n"; - if ($typeflag == 2) { # symbolic link - print FI "data ", length($linkname), "\n", $linkname; - $mode = 0120000; - } else { - print FI "data $size\n"; - while ($size > 0 && read(I, $_, 512) == 512) { - print FI substr($_, 0, $size); - $size -= 512; + if ($typeflag != 1) { # handle hard links later + print FI "blob\n", "mark :$next_mark\n"; + if ($typeflag == 2) { # symbolic link + print FI "data ", length($linkname), "\n", + $linkname; + $mode = 0120000; + } else { + print FI "data $size\n"; + while ($size > 0 && read(I, $_, 512) == 512) { + print FI substr($_, 0, $size); + $size -= 512; + } } + print FI "\n"; } - print FI "\n"; my $path; if ($prefix) { @@ -115,7 +118,13 @@ foreach my $tar_file (@ARGV) } else { $path = "$name"; } - $files{$path} = [$next_mark++, $mode]; + + if ($typeflag == 1) { # hard link + $linkname = "$prefix/$linkname" if $prefix; + $files{$path} = [ $files{$linkname}->[0], $mode ]; + } else { + $files{$path} = [$next_mark++, $mode]; + } $author_time = $mtime if $mtime > $author_time; $path =~ m,^([^/]+)/,; -- 2.9.0.281.g286a8d9 base-commit: f8f7adce9fc50a11a764d57815602dcb818d1816 ``` ## Junio C Hamano, 2016-08-03 16:45 Subject: Re: [PATCH] import-tars: support hard links Message-ID: URL: https://gitlist.dev/e/xmqqinvhaji7.fsf%40gitster.mtv.corp.google.com In-Reply-To: ``` Johannes Schindelin writes: > Previously, we simply treated hard links as if they were plain files > with size 0, ignoring the link type "1" and hence the link target. Nicely spotted and explained. > Signed-off-by: Johannes Schindelin > --- > Published-As: https://github.com/dscho/git/releases/tag/import-tars-hardlink-v1 A link to a page that lets you download entire source tarball is not very useful to most people, except for those who want "this exact change on top of some unknown base which may or may not have other things they need", which I think is a minority. Can you also (or instead) point at a branch/tag that people can do git fetch $repo $branch more easily? > contrib/fast-import/import-tars.perl | 31 ++++++++++++++++++++----------- > 1 file changed, 20 insertions(+), 11 deletions(-) > > diff --git a/contrib/fast-import/import-tars.perl b/contrib/fast-import/import-tars.perl > index 95438e1..d60b431 100755 > --- a/contrib/fast-import/import-tars.perl > +++ b/contrib/fast-import/import-tars.perl > @@ -96,18 +96,21 @@ foreach my $tar_file (@ARGV) > $mtime = oct $mtime; > next if $typeflag == 5; # directory > > - print FI "blob\n", "mark :$next_mark\n"; > - if ($typeflag == 2) { # symbolic link > - print FI "data ", length($linkname), "\n", $linkname; > - $mode = 0120000; > - } else { > - print FI "data $size\n"; > - while ($size > 0 && read(I, $_, 512) == 512) { > - print FI substr($_, 0, $size); > - $size -= 512; > + if ($typeflag != 1) { # handle hard links later > + print FI "blob\n", "mark :$next_mark\n"; > + if ($typeflag == 2) { # symbolic link > + print FI "data ", length($linkname), "\n", > + $linkname; > + $mode = 0120000; > + } else { > + print FI "data $size\n"; > + while ($size > 0 && read(I, $_, 512) == 512) { > + print FI substr($_, 0, $size); > + $size -= 512; > + } > } > + print FI "\n"; > } > - print FI "\n"; The resulting if/else cascade initially looked a bit unnatural (naively I would have expected that a new "elsif ($typeflag == 1)" would be inserted before the final "else" currently is). Because you have to do avoid giving a new mark to hardlink entries, and that fact would not change regardless of what values of $typeflag other than 1 exists in the imported tars, so I think the resulting code structure makes a lot of sense. We may want to add more elsif to notice and ignore/warn/substitute things like CHRTYPE/BLKTYPE by enhancing the if/else cascade inside the "if ($typeflag != 1)" introduced by this patch, but the code structure does not have to change when such an enhancement happens. Nicely done. > my $path; > if ($prefix) { > @@ -115,7 +118,13 @@ foreach my $tar_file (@ARGV) > } else { > $path = "$name"; > } > - $files{$path} = [$next_mark++, $mode]; > + > + if ($typeflag == 1) { # hard link > + $linkname = "$prefix/$linkname" if $prefix; > + $files{$path} = [ $files{$linkname}->[0], $mode ]; > + } else { > + $files{$path} = [$next_mark++, $mode]; > + } > > $author_time = $mtime if $mtime > $author_time; > $path =~ m,^([^/]+)/,; ``` ## Johannes Schindelin, 2016-08-04 14:59 Subject: Re: [PATCH] import-tars: support hard links Message-ID: URL: https://gitlist.dev/e/alpine.DEB.2.20.1608041658220.5786%40virtualbox In-Reply-To: ``` Hi Junio, On Wed, 3 Aug 2016, Junio C Hamano wrote: > Johannes Schindelin writes: > > > --- > > Published-As: https://github.com/dscho/git/releases/tag/import-tars-hardlink-v1 > > A link to a page that lets you download entire source tarball is not > very useful to most people, except for those who want "this exact > change on top of some unknown base which may or may not have other > things they need", which I think is a minority. True. I added a second line that describes how to fetch it (see the t5533 patch I just sent out). Ciao, Dscho ```