Tar/untar now correctly supports symlinks.

[FIXED JENKINS-12119] rolling back a portion of 46998ba0446834de0c725c32b328ace7ce844f6a as this is binary incompatible change

Just import changes, from hudson.model.Jenkins -> jenkins.model.Jenkins,
and Javadoc comments.
Signed-off-by: NNigel Magnay <nigel.magnay@gmail.com>

Signed-off-by: NNigel Magnay <nigel.magnay@gmail.com>

Note that the above description is incorrect as to what the merge was about.
It is the message that I intended to make. It appears that I accidentaly merged multiple fixes waiting to be reviewed on my private fork.

This reverts commit dce0d2af, reversing
changes made to 63f67f30.

Some more work:
* reviewed some callers
* took note that some classes have been moved into stapler
* used IOUtil.closeQuietly() in a few places

First pass at making sure we don't stop copying when the reader reads 0 characters.

I will now also review the callers for our internal code, and check if we can use IOUtils methods instead.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@36130 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@34030 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@33532 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@31921 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@30794 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@30734 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@30074 71c3de6d-444a-0410-be80-ed276b4c234a

report more details if symlink creation fails, or else it's impossible for the operator to act on the problem.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@28750 71c3de6d-444a-0410-be80-ed276b4c234a

class initialization of Hudson is much more work than that of Util, so pushing these small utilities out to Util to reduce the overhead of remoting.

Plus it helps to keep Hudson.java smaller

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@27448 71c3de6d-444a-0410-be80-ed276b4c234a

[FIXED HUDSON-5155] in 1.342. The root cause of the problem is that the backing byte[] of ByteBuffer can be bigger than the actual current content that's on it --- in the case of the reporter he got byte[3] as the backing buffer when only two bytes of it is in use.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@25962 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@25648 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@24575 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@24373 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@24103 71c3de6d-444a-0410-be80-ed276b4c234a

link points to a non-existent file/dir (in this case File.exists() returns
false, so it was not removed before creating new symlink).
This change also avoids exec of "rm -rf" when simple File.delete() succeeds.


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@23972 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@23471 71c3de6d-444a-0410-be80-ed276b4c234a

If so, don't use posix in Util.createSymlink.
When posix IS used but fails, include errno in log.


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@23470 71c3de6d-444a-0410-be80-ed276b4c234a