Antoine Levy-Lambert wrote:
----- Original Message ----- From: "Gus Heck" <[EMAIL PROTECTED]> Sent: Tuesday, August 12, 2003 4:10 PM
Antoine,
Since you have recently been playing with symlinks/FTP what are your thoughts on bug 14320?
http://nagoya.apache.org/bugzilla/show_bug.cgi?id=14320
First the bad news : I do not have the time to work on this in the frame of
ant 1.6. I am concerned that this might open a large Pandora box. :-(
Fair enough :)
Once ant 1.6 is released, I would like to discuss again the topic of "Resource(s)" and/or Jakarta-Common VFS. I would like to evaluate the use of Jakarta-Common VFS in ant, so that ant does not need to reinvent the wheel for everything. Just a thought at the moment, might be wrong.
hmm I should find out what Jakarta-Common VFS is :)
<snip>
Manipulating the symbolic link as a link is doable in a portable way for
packaging tasks (zip, jar, war, ear, tar). I am not sure what is the API to
find the target of the symbolic link (do an exec of ls -L and read the
result, or go the JNI route ?) ...
Parsing command line output seems dicey and brittle.
*** We need another attribute for filesets and directoryscanner called
preservesymlinks. ***
<GUS>
I can imagine that one could add an atribute that caused an OS check and if
we
it is a *nix set a flag that caused copy to use FileUtils.isSymbolicLink to
identify symlinks. symlinks could then be reproduced in either absolute form
or
minimum relative form or not reproduced in the destination directory based
on an
atribute such as copySymlinksAs="none"|"absolute"|"minRelative"
I don't know how much time I can put into it, but I'd be willing to try that
if
it sounds like a good idea to anyone else.
</GUS>
<ANTOINE>
Does "minRelative" mean relative to the root dir of the fileset ?
Maybe "asis" would be a good option too, to copy somelink -> ../../foo/bar
as ../../foo/bar
</ANTOINE>
/usr/local/storage/links/link2foo -> /usr/local/storage/gus/baz/bar/foo
is also equivalent to the following
/usr/local/storage/links/lin2foo -> ../../../../user/local/storage/gus/baz/bar/foo
/usr/local/storage/links/lin2foo -> ../../../local/storage/gus/baz/bar/foo
/usr/local/storage/links/lin2foo -> ../../storage/gus/baz/bar/foo
/usr/local/storage/links/lin2foo -> ../gus/baz/bar/foo
The last of these is what I call minRelative. (I don't know if there is a more standard term).
I currently convert all links in my website to this form by execing the linux command
(not the ant task): "symlinks -rcs" from the document root twice. The first invocation changes absolute to relative, and the second reduces the lenghthy links to minimal links. I do not know if this command is available on other *nix platforms.
It should also be possible to compare the canoniacal path of the dir the link is to be created in and the canonical path of the target of the link and calculate the minimum number of ../ 's needed to create the link and get "minRelative" that way.
Maintaining asis requires direct knowledge of which of the 4 posibilities above was on the file system, and probably does require parsing output of ln or ls or whatever. "minRelative" links are of particular to me interest because they are the least likely to break when moving directories containing links around. The first of the 4 relative links always breaks, if it gets moved up or down a level, but if I move /usr/local/storage to /usr/local/old/storage then the last two forms still work. My website build creates links in a tempdir before moving the whole thing to where the world can see it (assuming all went well).
This attribute would only be legal with followsymlinks="false" (since true means manipulate the objects pointed to by the links).
Then we need to define task by task how to use preservesymlinks/copysimlinks="none"|"absolute"|"minRelative" <AFAIK> <ANT> Symbolic links do not exist in Windows (for ant's FileUtils#isSymbolicLink) Symbolic links can be created via the symlink task, which relies on ln -s available in the operating system </ANT>
agree
lnk files have substantial functional differences. a .lnk to a directory cannot be included in the middle of a path as such: C:\projects\ant.lnk\src\main ... this won't work, but of course does work with symlinks. I have heard that there is something like symlinks out there called "reparse points" but I really don't know anything other than the name. (google searches a year ago wern't too fruitful on the topic, but this may have changed).<WINDOWS> .lnk files exist non .lnk links exist not aware of command line utility distributed with all versions of the OS to do this aware of ln.exe in cygwin aware of shortcut.exe, a program which is part of the Windows NT resource kit of Microsoft </WINDOWS>
<UNIX> the area where symbolic links support should be least problematic, except for possible exceptions due to media not accepting symbolic links </UNIX> </AFAIK>
Apart from <copy/>, packaging tasks are good candidates for having the option of copying/preserving symbolic links. They would only be impacted if they run on UNIX.
Antoine
That sounds good to me.
-Gus
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