This fixes the errorprone warning OperatorPrecedence.

Change-Id: I4c7dafa5ac8e1d58fa15cf91fe1b3cf3f182d536

HostEntry class was public with empty constructor, so adding
constructors with default visibility actually reduced visibility of
constructor.

Change-Id: I4c996c0559102084946ba49a71afe10dda5e0f95

Errorprone raised error OperatorPrecedence in bazel build.

Change-Id: Ibab601e67d4d5cafe9a7d900c78b0d432181a073
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

Use Character.isWhitespace() instead of Character.isSpaceChar() to
treat TABs as whitespace, too.

Change-Id: Iffc59c13357d981ede6a1e0feb6ea6ff03fb3064
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

Negated patterns were handled wrongly. According to the OpenBSD
ssh_config man page,[1] a negated pattern never matches. Negated
patterns make only sense if there are positive patterns; the
negated pattern then can define exceptions for the positive
patterns.

OpenSshConfigFile did this wrongly. It handled "!foo" as "matching
everything but foo", but actually the semantics is "if the input is
"foo", this entry doesn't apply. If the input is anything else,
other patterns determine whether the entry may apply.".

[1] https://man.openbsd.org/ssh_config

Change-Id: I50f6e46581b7ece4c949eddf62f4a265573ec29e
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

OpenSSH 8.4 has introduced simple environment variable substitution
for some keys. Implement that feature in our ssh config file parser,
too.

Bug: 572103
Change-Id: I360f2c5510eea4ec3329aeedf3d29dfefc9163f0
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

OpenSSH has changed some things in ssh config files. Update our parser
to implement some of these changes:

* ignore trailing comments on a line
* rename PubkeyAcceptedKeyTypes to PubkeyAcceptedAlgorithms

Note that for the rename, openSSH still accepts both names. We do the
same, translating names whenever we get or set values.

Change-Id: Icccca060e6a4350a7acf05ff9e260f2c8c60ee1a
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

A builder API provides a more convenient way to define a customized
SshdSessionFactory by hiding the subclassing.

Also provide a new interface SshConfigStore to abstract away the
specifics of reading a ssh config file, and provide a way to customize
the concrete ssh config implementation to be used. This facilitates
using an alternate ssh config implementation that may or may not be
based on files.

Change-Id: Ib9038e8ff2a4eb3a9ce7b3554d1450befec8e1e1
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

This is the format given by the Eclipse legal doc generator [1].

[1] https://www.eclipse.org/projects/tools/documentation.php?id=technology.jgit

Bug: 548298
Change-Id: I8d8cabc998ba1b083e3f0906a8d558d391ffb6c4
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

Since [1] the gerrit project includes jgit as a submodule, and has this
warning enabled, resulting in 100s of warnings in the console.

Also enable the warning here, and fix them.

At the same time, add missing braces around adjacent and nearby one-line
blocks.

[1] https://gerrit-review.googlesource.com/c/gerrit/+/227897

Change-Id: I81df3fc7ed6eedf6874ce1a3bedfa727a1897e4c
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

Move the bulk of the basic parsing and host entry handling into a
new class OpenSshConfigFile that has no dependencies on any concrete
ssh implementation. Make the existing OpenSshConfig use the new
parser.

Introduce a new class SshConstants collecting all the various ssh-
related string literals. Also use TreeMaps with a case-insensitive
key comparator instead of converting keys to uppercase. Add a test
to verify that keys are matched case-insensitively.

Most of the parsing code was simply moved, except that the new
parser supports looking up entries given host name, port, and user
name, and can thus handle more %-substitutions correctly. This
feature is not yet used and cannot be used with JSch since JSch
only has a ConfigRepository.getConfig(String) interface.

The split is still worth the trouble as it opens the way to using
another ssh client altogether. Apache MINA sshd, for instance,
resolves host entries giving host name, port, and user name.

(Apache MINA has a built-in ssh config handling, but that has
problems, too: its pattern matching is case-insensitive, and its
merging of host entries if several match is not the same as in
OpenSsh. But with this refactoring, it will be possible to plug in
OpenSshConfigFile into an Apache MINA sshd  client without dragging
along JSch.)

One test case that doesn't make sense anymore has been removed. It
tested that repeatedly querying for a host entry returned the same
object. That is no longer true since the caching has been moved to
a deeper level.

Bug: 520927
Change-Id: I6381d52b29099595e6eaf8b05c786aeeaefbf9cc
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>