RFR: 8173970: jar tool should have a way to extract to a directory

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RFR: 8173970: jar tool should have a way to extract to a directory

Jaikiran Pai-3
Can I please get a review for this patch which proposes to implement the enhancement request noted in https://bugs.openjdk.java.net/browse/JDK-8173970?

The commit in this PR introduces the `-o` and `--output-dir` option to the `jar` command. The option takes a path to a destination directory as a value and extracts the contents of the jar into that directory. This is an optional option and the changes in the commit continue to maintain backward compatibility where the jar is extracted into current directory, if no `-o` or `--output-dir` option has been specified.

As far as I know, there hasn't been any discussion on what the name of this new option should be. I was initially thinking of using `-d` but that is currently used by the `jar` command for a different purpose. So I decided to use `-o` and `--output-dir`. This is of course open for change depending on any suggestions in this PR.

The commit in this PR also updates the `jar.properties` file which contains the English version of the jar command's `--help` output. However, no changes have been done to the internationalization files corresponding to this one (for example: `jar_de.properties`), because I don't know what process needs to be followed to have those files updated (if at all they need to be updated).

The commit also includes a jtreg testcase which verifies the usage of this new option.

-------------

Commit messages:
 - 8173970: jar tool should have a way to extract to a directory

Changes: https://git.openjdk.java.net/jdk/pull/2752/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2752&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8173970
  Stats: 268 lines in 4 files changed: 262 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2752.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2752/head:pull/2752

PR: https://git.openjdk.java.net/jdk/pull/2752
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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Lance Andersen-3
Hi Jaikiran,

Thank you for  the proposed patch.

Assuming there is consensus to add support for this enhancement, I think we need to discuss what is the correct option.

The jar tool borrows -C from tar for creating/updating a jar and the -C option is also a valid option when extracting files from a tar file.    

Perhaps keeping symmetry with tar and extend support for -C when extracting a jar file would be a better way forward.   Let’s give time for additional input.

I believe this would also warrant a CSR to be created as well as updates to the jar man page.

Best
Lance

p.s. I think it would be useful in the future to start the discussion on core-libs-dev prior to creating a PR (or leave it as a draft PR) for a feature request.

On Feb 26, 2021, at 12:08 PM, Jaikiran Pai <[hidden email]> wrote:

Can I please get a review for this patch which proposes to implement the enhancement request noted in https://bugs.openjdk.java.net/browse/JDK-8173970?

The commit in this PR introduces the `-o` and `--output-dir` option to the `jar` command. The option takes a path to a destination directory as a value and extracts the contents of the jar into that directory. This is an optional option and the changes in the commit continue to maintain backward compatibility where the jar is extracted into current directory, if no `-o` or `--output-dir` option has been specified.

As far as I know, there hasn't been any discussion on what the name of this new option should be. I was initially thinking of using `-d` but that is currently used by the `jar` command for a different purpose. So I decided to use `-o` and `--output-dir`. This is of course open for change depending on any suggestions in this PR.

The commit in this PR also updates the `jar.properties` file which contains the English version of the jar command's `--help` output. However, no changes have been done to the internationalization files corresponding to this one (for example: `jar_de.properties`), because I don't know what process needs to be followed to have those files updated (if at all they need to be updated).

The commit also includes a jtreg testcase which verifies the usage of this new option.

-------------

Commit messages:
- 8173970: jar tool should have a way to extract to a directory

Changes: https://git.openjdk.java.net/jdk/pull/2752/files
Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2752&range=00
 Issue: https://bugs.openjdk.java.net/browse/JDK-8173970
 Stats: 268 lines in 4 files changed: 262 ins; 0 del; 6 mod
 Patch: https://git.openjdk.java.net/jdk/pull/2752.diff
 Fetch: git fetch https://git.openjdk.java.net/jdk pull/2752/head:pull/2752

PR: https://git.openjdk.java.net/jdk/pull/2752




Lance Andersen| Principal Member of Technical Staff | +1.781.442.2037
Oracle Java Engineering 
1 Network Drive 
Burlington, MA 01803
[hidden email]



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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Jaikiran Pai
Hello Lance,

On 27/02/21 1:17 am, Lance Andersen wrote:
>
>
> p.s. I think it would be useful in the future to start the discussion
> on core-libs-dev prior to creating a PR (or leave it as a draft PR)
> for a feature request.

Thank you for that input, I'll keep that in mind for any similar work in
future.


-Jaikiran

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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Jaikiran Pai
In reply to this post by Lance Andersen-3

On 27/02/21 1:17 am, Lance Andersen wrote:
>
> I believe this would also warrant a CSR to be created as well as
> updates to the jar man page.


I haven't created a CSR before, so I will need some guidance on that
part. Is it usually created after all the implementation details have
been decided upon or should it be created now?

-Jaikiran

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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Alan Bateman
In reply to this post by Lance Andersen-3
On 26/02/2021 19:47, Lance Andersen wrote:

> Hi Jaikiran,
>
> Thank you for  the proposed patch.
>
> Assuming there is consensus to add support for this enhancement, I think we need to discuss what is the correct option.
>
> The jar tool borrows -C from tar for creating/updating a jar and the -C option is also a valid option when extracting files from a tar file.
>
> Perhaps keeping symmetry with tar and extend support for -C when extracting a jar file would be a better way forward.   Let’s give time for additional input.
>
> I believe this would also warrant a CSR to be created as well as updates to the jar man page.
>
> Best
> Lance
>
> p.s. I think it would be useful in the future to start the discussion on core-libs-dev prior to creating a PR (or leave it as a draft PR) for a feature request.
I created JDK-8173970 a few years ago so happy it it getting some attention.

Yes, the option name will need to be agreed. It would be useful to
enumerate the options that the other tools are using to specify the
location where to extract. If you see JBS issues mentioning tar -C not
supporting chdir when extracting then it might be Solaris tar, which
isn't the same as GNU tar which has different options. It might be
better to look at more main stream tools, like unzip although jar -d is
already taken. It would be nice if there were some consistency with
other tools in the JDK that doing extracting (The jmod and jimage
extract commands use use --dir for example).

There are other discussion points around the behavior when the target
directory exists or does not exist, to ensure there is some consistency
with main stream tools.

Yes, a CSR will be needed.

-Alan




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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Lance Andersen-3
In reply to this post by Jaikiran Pai
HI Jaikiran,

I am more than happy to work with you through the CSR process

Lets get the discussion going regarding possible option names on core-libs-dev and then we can move forward :-)

Have a great weekend

On Feb 26, 2021, at 9:03 PM, Jaikiran Pai <[hidden email]> wrote:


On 27/02/21 1:17 am, Lance Andersen wrote:

I believe this would also warrant a CSR to be created as well as updates to the jar man page.


I haven't created a CSR before, so I will need some guidance on that part. Is it usually created after all the implementation details have been decided upon or should it be created now?

-Jaikiran





Lance Andersen| Principal Member of Technical Staff | +1.781.442.2037
Oracle Java Engineering 
1 Network Drive 
Burlington, MA 01803
[hidden email]



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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Jaikiran Pai
In reply to this post by Alan Bateman
Hello Alan,

On 27/02/21 2:23 pm, Alan Bateman wrote:

>
> Yes, the option name will need to be agreed. It would be useful to
> enumerate the options that the other tools are using to specify the
> location where to extract. If you see JBS issues mentioning tar -C not
> supporting chdir when extracting then it might be Solaris tar, which
> isn't the same as GNU tar which has different options. It might be
> better to look at more main stream tools, like unzip although jar -d
> is already taken. It would be nice if there were some consistency with
> other tools in the JDK that doing extracting (The jmod and jimage
> extract commands use use --dir for example).

I had a look at both tar and unzip commands on MacOS and Linux (CentOS)
setup that I had access to.

--------------
tar on MacOS:
--------------

tar --version
bsdtar 3.3.2 - libarchive 3.3.2 zlib/1.2.11 liblzma/5.0.5 bz2lib/1.0.6

The version of this tool has:

-C directory, --cd directory, --directory directory
              In c and r mode, this changes the directory before adding
the following files.
              In x mode, change directories after opening the archive
but before extracting
              entries from the archive.

A command like "tar -xzf foo.tar.gz -C /tmp/bar/" works fine and
extracts the foo.tar.gz from current directory to a target directory
/tmp/bar/

--------------
tar on CentOS:
--------------

tar --version
tar (GNU tar) 1.26

This version of the tool has:

Common options:
        -C, --directory=DIR
               change to directory DIR

Although the wording isn't clear that, when used with -x, it extracts to
the directory specified in -C, it does indeed behave that way.

Specifically, a command like "tar -xzf foo.tar.gz -C /tmp/bar/" works
fine and extracts the foo.tar.gz from current directory to a target
directory /tmp/bar/

-------------------------------
unzip on both MacOS and CentOS:
-------------------------------

unzip -v
UnZip 6.00 of 20 April 2009, by Info-ZIP.  Maintained by C. Spieler.

This version of the tool has:

[-d exdir]
               An optional directory to which to extract files.  By
default, all files and sub-
               directories are recreated in the current directory; the
-d option allows extrac-
               tion in an arbitrary directory (always assuming one has
permission to  write  to
               the  directory).  This option need not appear at the end
of the command line; it
               is also accepted before the zipfile specification (with 
the  normal  options),
               immediately  after  the zipfile specification, or between
the file(s) and the -x
               option.  The option and directory may be concatenated
without  any  white  space
               between  them,  but  note  that  this may cause normal
shell behavior to be sup-
               pressed.  In particular, ``-d ~'' (tilde) is expanded by
Unix C shells into  the
               name of the user's home directory, but ``-d~'' is treated
as a literal subdirec-
               tory ``~'' of the current directory.

unzip foo.zip -d /tmp/bar/ works fine and extracts the foo.zip from
current directory to /tmp/bar/

---------------
jimage and jmod
---------------

The jimage and jmod as you note use the --dir option for extracting to
that specified directory.


Those were the tools I looked at. I think using the -d option with -x
for the jar command is ruled out since it already is used for a
different purpose, although for a different "main" operation of the jar
command.

As for using --dir for this new feature, I don't think it alone will be
enough. Specifically, I couldn't find a "short form" option for the
--dir option in the jimage or jmod commands. For the jar extract feature
that we are discussing here, I think having a short form option (in
addition to the longer form) is necessary to have it match the usage
expectations of similar other options that the jar command exposes. So
even if we do choose --dir as the long form option, we would still need
a short form for it and since -d is already taken for something else, we
would still need to come up with a different one. The short form of this
option could be -C (see below).


I think reusing the -C option, for this new feature, perhaps is a good
thing. The -C is currently used by the update and create "main"
operation of the jar command and the man page for this option states:

-C dir
               When creating (c) or updating (u) a JAR file, this option
temporarily changes
               the directory while processing files specified by the
file operands. Its
               operation is intended to be similar to the -C option of
the UNIX tar utility.For
               example, the following command changes to the classes
directory and adds the
               Bar.class file from that directory to my.jar:

               jar uf my.jar -C classes Bar.class
....

Using the -C option would indeed align it with the tar command. For the
"long form" of this option, the tar command (both on MacOS and CentOS)
uses --directory. For this jar extract feature though, we could perhaps
just use --dir to have it align with the jimage and the jmod tools.

So I think the combination of -C (short form) and --dir (long form)
would perhaps be suitable for this feature.


>
> There are other discussion points around the behavior when the target
> directory exists or does not exist, to ensure there is some
> consistency with main stream tools.

I'm guessing you mean the behaviour of creating a directory (or a
hierarchy of directories) if the target directory is not present? My
testing with the tar tool (both on MacOS and CentOS) shows that if the
specified target directory doesn't exist, then the extract fails. The
tar extract command doesn't create the target directory during extract.
On the other hand, the unzip tool, does create the directory if it
doesn't exist. However, interestingly, the unzip tool creates only one
level of that directory if it doesn't exist. Specifically, if you specify:

unzip foo.zip -d /tmp/blah/

and if "blah/" isn't a directory inside /tmp/ directory, then it creates
the "blah/" directory inside /tmp/ and then extracts the contents of the
zip into it.

However,

unzip foo.zip -d /tmp/blah/hello/

and if "blah/" isn't a directory inside /tmp/ directory, then this
command fails with an error and it doesn't create the hierarchy of the
target directories.

Coming to the jimage and the jmod commands, both these commands create
the entire directory hierarchy if the target directory specified during
extract, using --dir, doesn't exist. So a command like:

jimage extract --dir /tmp/blah/foo/bar/ jdkmodules

will create the blah/foo/bar/ directory hierarchy if blah doesn't exist
in /tmp/, while extracting the "jdkmodules" image.

 From the user point of view, I think this behaviour of creating the
directories if the target directory doesn't exist, is probably the most
intuitive and useful and if we did decide to use this approach for this
new option for jar extract command, then it would align with what we
already do in jimage and jmod commands.

One another minor detail, while we are at this, is that, IMO we should
let the jar extract command to continue to behave the way it currently
does when it comes to overwriting existing files. If the jar being
extracted contains a file by the same name, in the target directory
(hierarchy) then it should continue to overwrite that file. In other
words, I don't think we should change the way the jar extract command
currently behaves where it overwrites existing files when extracting.


-Jaikiran


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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Lance Andersen-3
Hi Jaikiran,

Thank you for this.  I went through this myself yesterday in addition to what you have below here are a few more:

7zip:       -o 
Info-zip:  -d  (MacOS version of zip)
Bandzip: -o:{dir}
jpackage: -d —dest
jlink —output


Thinking about this some more, I might suggest supporting

-C
—dir
—directory

Best
Lance

On Feb 27, 2021, at 11:19 PM, Jaikiran Pai <[hidden email]> wrote:

Hello Alan,

On 27/02/21 2:23 pm, Alan Bateman wrote:

Yes, the option name will need to be agreed. It would be useful to enumerate the options that the other tools are using to specify the location where to extract. If you see JBS issues mentioning tar -C not supporting chdir when extracting then it might be Solaris tar, which isn't the same as GNU tar which has different options. It might be better to look at more main stream tools, like unzip although jar -d is already taken. It would be nice if there were some consistency with other tools in the JDK that doing extracting (The jmod and jimage extract commands use use --dir for example).

I had a look at both tar and unzip commands on MacOS and Linux (CentOS) setup that I had access to.

--------------
tar on MacOS:
--------------

tar --version
bsdtar 3.3.2 - libarchive 3.3.2 zlib/1.2.11 liblzma/5.0.5 bz2lib/1.0.6

The version of this tool has:

-C directory, --cd directory, --directory directory
             In c and r mode, this changes the directory before adding the following files.
             In x mode, change directories after opening the archive but before extracting
             entries from the archive.

A command like "tar -xzf foo.tar.gz -C /tmp/bar/" works fine and extracts the foo.tar.gz from current directory to a target directory /tmp/bar/

--------------
tar on CentOS:
--------------

tar --version
tar (GNU tar) 1.26

This version of the tool has:

Common options:
       -C, --directory=DIR
              change to directory DIR

Although the wording isn't clear that, when used with -x, it extracts to the directory specified in -C, it does indeed behave that way.

Specifically, a command like "tar -xzf foo.tar.gz -C /tmp/bar/" works fine and extracts the foo.tar.gz from current directory to a target directory /tmp/bar/

-------------------------------
unzip on both MacOS and CentOS:
-------------------------------

unzip -v
UnZip 6.00 of 20 April 2009, by Info-ZIP.  Maintained by C. Spieler.

This version of the tool has:

[-d exdir]
              An optional directory to which to extract files.  By default, all files and sub-
              directories are recreated in the current directory; the -d option allows extrac-
              tion in an arbitrary directory (always assuming one has permission to  write  to
              the  directory).  This option need not appear at the end of the command line; it
              is also accepted before the zipfile specification (with  the  normal  options),
              immediately  after  the zipfile specification, or between the file(s) and the -x
              option.  The option and directory may be concatenated without  any  white  space
              between  them,  but  note  that  this may cause normal shell behavior to be sup-
              pressed.  In particular, ``-d ~'' (tilde) is expanded by Unix C shells into  the
              name of the user's home directory, but ``-d~'' is treated as a literal subdirec-
              tory ``~'' of the current directory.

unzip foo.zip -d /tmp/bar/ works fine and extracts the foo.zip from current directory to /tmp/bar/

---------------
jimage and jmod
---------------

The jimage and jmod as you note use the --dir option for extracting to that specified directory.


Those were the tools I looked at. I think using the -d option with -x for the jar command is ruled out since it already is used for a different purpose, although for a different "main" operation of the jar command.

As for using --dir for this new feature, I don't think it alone will be enough. Specifically, I couldn't find a "short form" option for the --dir option in the jimage or jmod commands. For the jar extract feature that we are discussing here, I think having a short form option (in addition to the longer form) is necessary to have it match the usage expectations of similar other options that the jar command exposes. So even if we do choose --dir as the long form option, we would still need a short form for it and since -d is already taken for something else, we would still need to come up with a different one. The short form of this option could be -C (see below).


I think reusing the -C option, for this new feature, perhaps is a good thing. The -C is currently used by the update and create "main" operation of the jar command and the man page for this option states:

-C dir
              When creating (c) or updating (u) a JAR file, this option temporarily changes
              the directory while processing files specified by the file operands. Its
              operation is intended to be similar to the -C option of the UNIX tar utility.For
              example, the following command changes to the classes directory and adds the
              Bar.class file from that directory to my.jar:

              jar uf my.jar -C classes Bar.class
....

Using the -C option would indeed align it with the tar command. For the "long form" of this option, the tar command (both on MacOS and CentOS) uses --directory. For this jar extract feature though, we could perhaps just use --dir to have it align with the jimage and the jmod tools.

So I think the combination of -C (short form) and --dir (long form) would perhaps be suitable for this feature.



There are other discussion points around the behavior when the target directory exists or does not exist, to ensure there is some consistency with main stream tools.

I'm guessing you mean the behaviour of creating a directory (or a hierarchy of directories) if the target directory is not present? My testing with the tar tool (both on MacOS and CentOS) shows that if the specified target directory doesn't exist, then the extract fails. The tar extract command doesn't create the target directory during extract. On the other hand, the unzip tool, does create the directory if it doesn't exist. However, interestingly, the unzip tool creates only one level of that directory if it doesn't exist. Specifically, if you specify:

unzip foo.zip -d /tmp/blah/

and if "blah/" isn't a directory inside /tmp/ directory, then it creates the "blah/" directory inside /tmp/ and then extracts the contents of the zip into it.

However,

unzip foo.zip -d /tmp/blah/hello/

and if "blah/" isn't a directory inside /tmp/ directory, then this command fails with an error and it doesn't create the hierarchy of the target directories.

Coming to the jimage and the jmod commands, both these commands create the entire directory hierarchy if the target directory specified during extract, using --dir, doesn't exist. So a command like:

jimage extract --dir /tmp/blah/foo/bar/ jdkmodules

will create the blah/foo/bar/ directory hierarchy if blah doesn't exist in /tmp/, while extracting the "jdkmodules" image.

From the user point of view, I think this behaviour of creating the directories if the target directory doesn't exist, is probably the most intuitive and useful and if we did decide to use this approach for this new option for jar extract command, then it would align with what we already do in jimage and jmod commands.

One another minor detail, while we are at this, is that, IMO we should let the jar extract command to continue to behave the way it currently does when it comes to overwriting existing files. If the jar being extracted contains a file by the same name, in the target directory (hierarchy) then it should continue to overwrite that file. In other words, I don't think we should change the way the jar extract command currently behaves where it overwrites existing files when extracting.


-Jaikiran






Lance Andersen| Principal Member of Technical Staff | +1.781.442.2037
Oracle Java Engineering 
1 Network Drive 
Burlington, MA 01803
[hidden email]



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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Jaikiran Pai

Thank you Lance. So I think there's some level of agreement on using -C and --dir (or --directory) for the option names.

Anymore opinion on the directory creation semantics and any other aspects to consider?

-Jaikiran

On 28/02/21 5:38 pm, Lance Andersen wrote:
Hi Jaikiran,

Thank you for this.  I went through this myself yesterday in addition to what you have below here are a few more:

7zip:       -o 
Info-zip:  -d  (MacOS version of zip)
Bandzip: -o:{dir}
jpackage: -d —dest
jlink —output


Thinking about this some more, I might suggest supporting

-C
—dir
—directory

Best
Lance

On Feb 27, 2021, at 11:19 PM, Jaikiran Pai <[hidden email]> wrote:

Hello Alan,

On 27/02/21 2:23 pm, Alan Bateman wrote:

Yes, the option name will need to be agreed. It would be useful to enumerate the options that the other tools are using to specify the location where to extract. If you see JBS issues mentioning tar -C not supporting chdir when extracting then it might be Solaris tar, which isn't the same as GNU tar which has different options. It might be better to look at more main stream tools, like unzip although jar -d is already taken. It would be nice if there were some consistency with other tools in the JDK that doing extracting (The jmod and jimage extract commands use use --dir for example).

I had a look at both tar and unzip commands on MacOS and Linux (CentOS) setup that I had access to.

--------------
tar on MacOS:
--------------

tar --version
bsdtar 3.3.2 - libarchive 3.3.2 zlib/1.2.11 liblzma/5.0.5 bz2lib/1.0.6

The version of this tool has:

-C directory, --cd directory, --directory directory
             In c and r mode, this changes the directory before adding the following files.
             In x mode, change directories after opening the archive but before extracting
             entries from the archive.

A command like "tar -xzf foo.tar.gz -C /tmp/bar/" works fine and extracts the foo.tar.gz from current directory to a target directory /tmp/bar/

--------------
tar on CentOS:
--------------

tar --version
tar (GNU tar) 1.26

This version of the tool has:

Common options:
       -C, --directory=DIR
              change to directory DIR

Although the wording isn't clear that, when used with -x, it extracts to the directory specified in -C, it does indeed behave that way.

Specifically, a command like "tar -xzf foo.tar.gz -C /tmp/bar/" works fine and extracts the foo.tar.gz from current directory to a target directory /tmp/bar/

-------------------------------
unzip on both MacOS and CentOS:
-------------------------------

unzip -v
UnZip 6.00 of 20 April 2009, by Info-ZIP.  Maintained by C. Spieler.

This version of the tool has:

[-d exdir]
              An optional directory to which to extract files.  By default, all files and sub-
              directories are recreated in the current directory; the -d option allows extrac-
              tion in an arbitrary directory (always assuming one has permission to  write  to
              the  directory).  This option need not appear at the end of the command line; it
              is also accepted before the zipfile specification (with  the  normal  options),
              immediately  after  the zipfile specification, or between the file(s) and the -x
              option.  The option and directory may be concatenated without  any  white  space
              between  them,  but  note  that  this may cause normal shell behavior to be sup-
              pressed.  In particular, ``-d ~'' (tilde) is expanded by Unix C shells into  the
              name of the user's home directory, but ``-d~'' is treated as a literal subdirec-
              tory ``~'' of the current directory.

unzip foo.zip -d /tmp/bar/ works fine and extracts the foo.zip from current directory to /tmp/bar/

---------------
jimage and jmod
---------------

The jimage and jmod as you note use the --dir option for extracting to that specified directory.


Those were the tools I looked at. I think using the -d option with -x for the jar command is ruled out since it already is used for a different purpose, although for a different "main" operation of the jar command.

As for using --dir for this new feature, I don't think it alone will be enough. Specifically, I couldn't find a "short form" option for the --dir option in the jimage or jmod commands. For the jar extract feature that we are discussing here, I think having a short form option (in addition to the longer form) is necessary to have it match the usage expectations of similar other options that the jar command exposes. So even if we do choose --dir as the long form option, we would still need a short form for it and since -d is already taken for something else, we would still need to come up with a different one. The short form of this option could be -C (see below).


I think reusing the -C option, for this new feature, perhaps is a good thing. The -C is currently used by the update and create "main" operation of the jar command and the man page for this option states:

-C dir
              When creating (c) or updating (u) a JAR file, this option temporarily changes
              the directory while processing files specified by the file operands. Its
              operation is intended to be similar to the -C option of the UNIX tar utility.For
              example, the following command changes to the classes directory and adds the
              Bar.class file from that directory to my.jar:

              jar uf my.jar -C classes Bar.class
....

Using the -C option would indeed align it with the tar command. For the "long form" of this option, the tar command (both on MacOS and CentOS) uses --directory. For this jar extract feature though, we could perhaps just use --dir to have it align with the jimage and the jmod tools.

So I think the combination of -C (short form) and --dir (long form) would perhaps be suitable for this feature.



There are other discussion points around the behavior when the target directory exists or does not exist, to ensure there is some consistency with main stream tools.

I'm guessing you mean the behaviour of creating a directory (or a hierarchy of directories) if the target directory is not present? My testing with the tar tool (both on MacOS and CentOS) shows that if the specified target directory doesn't exist, then the extract fails. The tar extract command doesn't create the target directory during extract. On the other hand, the unzip tool, does create the directory if it doesn't exist. However, interestingly, the unzip tool creates only one level of that directory if it doesn't exist. Specifically, if you specify:

unzip foo.zip -d /tmp/blah/

and if "blah/" isn't a directory inside /tmp/ directory, then it creates the "blah/" directory inside /tmp/ and then extracts the contents of the zip into it.

However,

unzip foo.zip -d /tmp/blah/hello/

and if "blah/" isn't a directory inside /tmp/ directory, then this command fails with an error and it doesn't create the hierarchy of the target directories.

Coming to the jimage and the jmod commands, both these commands create the entire directory hierarchy if the target directory specified during extract, using --dir, doesn't exist. So a command like:

jimage extract --dir /tmp/blah/foo/bar/ jdkmodules

will create the blah/foo/bar/ directory hierarchy if blah doesn't exist in /tmp/, while extracting the "jdkmodules" image.

From the user point of view, I think this behaviour of creating the directories if the target directory doesn't exist, is probably the most intuitive and useful and if we did decide to use this approach for this new option for jar extract command, then it would align with what we already do in jimage and jmod commands.

One another minor detail, while we are at this, is that, IMO we should let the jar extract command to continue to behave the way it currently does when it comes to overwriting existing files. If the jar being extracted contains a file by the same name, in the target directory (hierarchy) then it should continue to overwrite that file. In other words, I don't think we should change the way the jar extract command currently behaves where it overwrites existing files when extracting.


-Jaikiran






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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Lance Andersen-3
Hi Jaikiran,

It should not be too difficult to support the options listed below via GNUStyleOptions.

Some other things needed to be defined and agreed upon in order to move forward

  • The behavior if the path does not exist
  • If the option is specified more than once on the command line
  • Clarify the behavior if any of the files exist in the specified target directory.


Once you have a chance to consider the above, please send your proposal back to the alias to continue the discussion 

Best
Lance

On Mar 3, 2021, at 5:14 AM, Jaikiran Pai <[hidden email]> wrote:

Thank you Lance. So I think there's some level of agreement on using -C and --dir (or --directory) for the option names.

Anymore opinion on the directory creation semantics and any other aspects to consider?

-Jaikiran

On 28/02/21 5:38 pm, Lance Andersen wrote:
Hi Jaikiran,

Thank you for this.  I went through this myself yesterday in addition to what you have below here are a few more:

7zip:       -o 
Info-zip:  -d  (MacOS version of zip)
Bandzip: -o:{dir}
jpackage: -d —dest
jlink —output


Thinking about this some more, I might suggest supporting

-C
—dir
—directory

Best
Lance

On Feb 27, 2021, at 11:19 PM, Jaikiran Pai <[hidden email]> wrote:

Hello Alan,

On 27/02/21 2:23 pm, Alan Bateman wrote:

Yes, the option name will need to be agreed. It would be useful to enumerate the options that the other tools are using to specify the location where to extract. If you see JBS issues mentioning tar -C not supporting chdir when extracting then it might be Solaris tar, which isn't the same as GNU tar which has different options. It might be better to look at more main stream tools, like unzip although jar -d is already taken. It would be nice if there were some consistency with other tools in the JDK that doing extracting (The jmod and jimage extract commands use use --dir for example).

I had a look at both tar and unzip commands on MacOS and Linux (CentOS) setup that I had access to.

--------------
tar on MacOS:
--------------

tar --version
bsdtar 3.3.2 - libarchive 3.3.2 zlib/1.2.11 liblzma/5.0.5 bz2lib/1.0.6

The version of this tool has:

-C directory, --cd directory, --directory directory
             In c and r mode, this changes the directory before adding the following files.
             In x mode, change directories after opening the archive but before extracting
             entries from the archive.

A command like "tar -xzf foo.tar.gz -C /tmp/bar/" works fine and extracts the foo.tar.gz from current directory to a target directory /tmp/bar/

--------------
tar on CentOS:
--------------

tar --version
tar (GNU tar) 1.26

This version of the tool has:

Common options:
       -C, --directory=DIR
              change to directory DIR

Although the wording isn't clear that, when used with -x, it extracts to the directory specified in -C, it does indeed behave that way.

Specifically, a command like "tar -xzf foo.tar.gz -C /tmp/bar/" works fine and extracts the foo.tar.gz from current directory to a target directory /tmp/bar/

-------------------------------
unzip on both MacOS and CentOS:
-------------------------------

unzip -v
UnZip 6.00 of 20 April 2009, by Info-ZIP.  Maintained by C. Spieler.

This version of the tool has:

[-d exdir]
              An optional directory to which to extract files.  By default, all files and sub-
              directories are recreated in the current directory; the -d option allows extrac-
              tion in an arbitrary directory (always assuming one has permission to  write  to
              the  directory).  This option need not appear at the end of the command line; it
              is also accepted before the zipfile specification (with  the  normal  options),
              immediately  after  the zipfile specification, or between the file(s) and the -x
              option.  The option and directory may be concatenated without  any  white  space
              between  them,  but  note  that  this may cause normal shell behavior to be sup-
              pressed.  In particular, ``-d ~'' (tilde) is expanded by Unix C shells into  the
              name of the user's home directory, but ``-d~'' is treated as a literal subdirec-
              tory ``~'' of the current directory.

unzip foo.zip -d /tmp/bar/ works fine and extracts the foo.zip from current directory to /tmp/bar/

---------------
jimage and jmod
---------------

The jimage and jmod as you note use the --dir option for extracting to that specified directory.


Those were the tools I looked at. I think using the -d option with -x for the jar command is ruled out since it already is used for a different purpose, although for a different "main" operation of the jar command.

As for using --dir for this new feature, I don't think it alone will be enough. Specifically, I couldn't find a "short form" option for the --dir option in the jimage or jmod commands. For the jar extract feature that we are discussing here, I think having a short form option (in addition to the longer form) is necessary to have it match the usage expectations of similar other options that the jar command exposes. So even if we do choose --dir as the long form option, we would still need a short form for it and since -d is already taken for something else, we would still need to come up with a different one. The short form of this option could be -C (see below).


I think reusing the -C option, for this new feature, perhaps is a good thing. The -C is currently used by the update and create "main" operation of the jar command and the man page for this option states:

-C dir
              When creating (c) or updating (u) a JAR file, this option temporarily changes
              the directory while processing files specified by the file operands. Its
              operation is intended to be similar to the -C option of the UNIX tar utility.For
              example, the following command changes to the classes directory and adds the
              Bar.class file from that directory to my.jar:

              jar uf my.jar -C classes Bar.class
....

Using the -C option would indeed align it with the tar command. For the "long form" of this option, the tar command (both on MacOS and CentOS) uses --directory. For this jar extract feature though, we could perhaps just use --dir to have it align with the jimage and the jmod tools.

So I think the combination of -C (short form) and --dir (long form) would perhaps be suitable for this feature.



There are other discussion points around the behavior when the target directory exists or does not exist, to ensure there is some consistency with main stream tools.

I'm guessing you mean the behaviour of creating a directory (or a hierarchy of directories) if the target directory is not present? My testing with the tar tool (both on MacOS and CentOS) shows that if the specified target directory doesn't exist, then the extract fails. The tar extract command doesn't create the target directory during extract. On the other hand, the unzip tool, does create the directory if it doesn't exist. However, interestingly, the unzip tool creates only one level of that directory if it doesn't exist. Specifically, if you specify:

unzip foo.zip -d /tmp/blah/

and if "blah/" isn't a directory inside /tmp/ directory, then it creates the "blah/" directory inside /tmp/ and then extracts the contents of the zip into it.

However,

unzip foo.zip -d /tmp/blah/hello/

and if "blah/" isn't a directory inside /tmp/ directory, then this command fails with an error and it doesn't create the hierarchy of the target directories.

Coming to the jimage and the jmod commands, both these commands create the entire directory hierarchy if the target directory specified during extract, using --dir, doesn't exist. So a command like:

jimage extract --dir /tmp/blah/foo/bar/ jdkmodules

will create the blah/foo/bar/ directory hierarchy if blah doesn't exist in /tmp/, while extracting the "jdkmodules" image.

From the user point of view, I think this behaviour of creating the directories if the target directory doesn't exist, is probably the most intuitive and useful and if we did decide to use this approach for this new option for jar extract command, then it would align with what we already do in jimage and jmod commands.

One another minor detail, while we are at this, is that, IMO we should let the jar extract command to continue to behave the way it currently does when it comes to overwriting existing files. If the jar being extracted contains a file by the same name, in the target directory (hierarchy) then it should continue to overwrite that file. In other words, I don't think we should change the way the jar extract command currently behaves where it overwrites existing files when extracting.


-Jaikiran



<oracle_sig_logo.gif>



Lance Andersen| Principal Member of Technical Staff | +1.781.442.2037
Oracle Java Engineering 
1 Network Drive 
Burlington, MA 01803
[hidden email]







Lance Andersen| Principal Member of Technical Staff | +1.781.442.2037
Oracle Java Engineering 
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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Jaikiran Pai

Hello Lance,

On 03/03/21 9:14 pm, Lance Andersen wrote:


Some other things needed to be defined and agreed upon in order to move forward

  • The behavior if the path does not exist
  • If the option is specified more than once on the command line
  • Clarify the behavior if any of the files exist in the specified target directory.

One of my previous reply included the details of how I think it should behave for 2 of the above cases. I'll paste that here again for easier visibility. As for how it should behave if the option is specified more than once, I'll spend some time today to see how the jar tool currently behaves for some of the other options in this aspect and send back my response. Thank you for your help so far. Pasting below my proposal from a previous reply for the other 2 cases:



There are other discussion points around the behavior when the target directory exists or does not exist, to ensure there is some consistency with main stream tools.

I'm guessing you mean the behaviour of creating a directory (or a hierarchy of directories) if the target directory is not present? My testing with the tar tool (both on MacOS and CentOS) shows that if the specified target directory doesn't exist, then the extract fails. The tar extract command doesn't create the target directory during extract. On the other hand, the unzip tool, does create the directory if it doesn't exist. However, interestingly, the unzip tool creates only one level of that directory if it doesn't exist. Specifically, if you specify:

unzip foo.zip -d /tmp/blah/

and if "blah/" isn't a directory inside /tmp/ directory, then it creates the "blah/" directory inside /tmp/ and then extracts the contents of the zip into it.

However,

unzip foo.zip -d /tmp/blah/hello/

and if "blah/" isn't a directory inside /tmp/ directory, then this command fails with an error and it doesn't create the hierarchy of the target directories.

Coming to the jimage and the jmod commands, both these commands create the entire directory hierarchy if the target directory specified during extract, using --dir, doesn't exist. So a command like:

jimage extract --dir /tmp/blah/foo/bar/ jdkmodules

will create the blah/foo/bar/ directory hierarchy if blah doesn't exist in /tmp/, while extracting the "jdkmodules" image.

From the user point of view, I think this behaviour of creating the directories if the target directory doesn't exist, is probably the most intuitive and useful and if we did decide to use this approach for this new option for jar extract command, then it would align with what we already do in jimage and jmod commands.

One another minor detail, while we are at this, is that, IMO we should let the jar extract command to continue to behave the way it currently does when it comes to overwriting existing files. If the jar being extracted contains a file by the same name, in the target directory (hierarchy) then it should continue to overwrite that file. In other words, I don't think we should change the way the jar extract command currently behaves where it overwrites existing files when extracting.

-Jaikiran

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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Lance Andersen-3
Hi Jaikiran 


The jar man page includes the following :
 The syntax for the jar command resembles the syntax for the tar command.

Because of the above, I feel that we should support:

———
-C
—dir
—directory
————

The addition of ‘-dir’ adds support for an option used by some of the other java command line tools.

I would suggest for the next step is flush/write out your proposed  syntax  as it would be included in an updated version of the jar man page.  

Given the other java command line tools create the directory if it does not exist, I think that is reasonable to propose that.

Your change should not modify the longstanding overwrite behavior of jar.

Another thing to think about is whether there should be any additional output when the -v option is specified

In summary, I think you are moving in the right direction.  The next step is to make a pass at creating the man page updates so that we can reach consensus on the syntax and behavior.

Thank you again for your efforts on this

Best
Lance

On Mar 3, 2021, at 9:40 PM, Jaikiran Pai <[hidden email]> wrote:

Hello Lance,

On 03/03/21 9:14 pm, Lance Andersen wrote:


Some other things needed to be defined and agreed upon in order to move forward

  • The behavior if the path does not exist
  • If the option is specified more than once on the command line
  • Clarify the behavior if any of the files exist in the specified target directory.

One of my previous reply included the details of how I think it should behave for 2 of the above cases. I'll paste that here again for easier visibility. As for how it should behave if the option is specified more than once, I'll spend some time today to see how the jar tool currently behaves for some of the other options in this aspect and send back my response. Thank you for your help so far. Pasting below my proposal from a previous reply for the other 2 cases:



There are other discussion points around the behavior when the target directory exists or does not exist, to ensure there is some consistency with main stream tools.

I'm guessing you mean the behaviour of creating a directory (or a hierarchy of directories) if the target directory is not present? My testing with the tar tool (both on MacOS and CentOS) shows that if the specified target directory doesn't exist, then the extract fails. The tar extract command doesn't create the target directory during extract. On the other hand, the unzip tool, does create the directory if it doesn't exist. However, interestingly, the unzip tool creates only one level of that directory if it doesn't exist. Specifically, if you specify:

unzip foo.zip -d /tmp/blah/

and if "blah/" isn't a directory inside /tmp/ directory, then it creates the "blah/" directory inside /tmp/ and then extracts the contents of the zip into it.

However,

unzip foo.zip -d /tmp/blah/hello/

and if "blah/" isn't a directory inside /tmp/ directory, then this command fails with an error and it doesn't create the hierarchy of the target directories.

Coming to the jimage and the jmod commands, both these commands create the entire directory hierarchy if the target directory specified during extract, using --dir, doesn't exist. So a command like:

jimage extract --dir /tmp/blah/foo/bar/ jdkmodules

will create the blah/foo/bar/ directory hierarchy if blah doesn't exist in /tmp/, while extracting the "jdkmodules" image.

From the user point of view, I think this behaviour of creating the directories if the target directory doesn't exist, is probably the most intuitive and useful and if we did decide to use this approach for this new option for jar extract command, then it would align with what we already do in jimage and jmod commands.

One another minor detail, while we are at this, is that, IMO we should let the jar extract command to continue to behave the way it currently does when it comes to overwriting existing files. If the jar being extracted contains a file by the same name, in the target directory (hierarchy) then it should continue to overwrite that file. In other words, I don't think we should change the way the jar extract command currently behaves where it overwrites existing files when extracting.

-Jaikiran





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Oracle Java Engineering 
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Re: RFR: 8173970: jar tool should have a way to extract to a directory [v2]

Jaikiran Pai-3
In reply to this post by Jaikiran Pai-3
> Can I please get a review for this patch which proposes to implement the enhancement request noted in https://bugs.openjdk.java.net/browse/JDK-8173970?
>
> The commit in this PR introduces the `-o` and `--output-dir` option to the `jar` command. The option takes a path to a destination directory as a value and extracts the contents of the jar into that directory. This is an optional option and the changes in the commit continue to maintain backward compatibility where the jar is extracted into current directory, if no `-o` or `--output-dir` option has been specified.
>
> As far as I know, there hasn't been any discussion on what the name of this new option should be. I was initially thinking of using `-d` but that is currently used by the `jar` command for a different purpose. So I decided to use `-o` and `--output-dir`. This is of course open for change depending on any suggestions in this PR.
>
> The commit in this PR also updates the `jar.properties` file which contains the English version of the jar command's `--help` output. However, no changes have been done to the internationalization files corresponding to this one (for example: `jar_de.properties`), because I don't know what process needs to be followed to have those files updated (if at all they need to be updated).
>
> The commit also includes a jtreg testcase which verifies the usage of this new option.

Jaikiran Pai has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains one additional commit since the last revision:

  8173970: jar tool should have a way to extract to a directory

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2752/files
  - new: https://git.openjdk.java.net/jdk/pull/2752/files/3a8e329d..a9954240

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2752&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2752&range=00-01

  Stats: 62407 lines in 2851 files changed: 39040 ins; 14156 del; 9211 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2752.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2752/head:pull/2752

PR: https://git.openjdk.java.net/jdk/pull/2752
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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Alan Bateman-2
In reply to this post by Jaikiran Pai-3
On Fri, 26 Feb 2021 17:03:11 GMT, Jaikiran Pai <[hidden email]> wrote:

> Can I please get a review for this patch which proposes to implement the enhancement request noted in https://bugs.openjdk.java.net/browse/JDK-8173970?
>
> The commit in this PR introduces the `-o` and `--output-dir` option to the `jar` command. The option takes a path to a destination directory as a value and extracts the contents of the jar into that directory. This is an optional option and the changes in the commit continue to maintain backward compatibility where the jar is extracted into current directory, if no `-o` or `--output-dir` option has been specified.
>
> As far as I know, there hasn't been any discussion on what the name of this new option should be. I was initially thinking of using `-d` but that is currently used by the `jar` command for a different purpose. So I decided to use `-o` and `--output-dir`. This is of course open for change depending on any suggestions in this PR.
>
> The commit in this PR also updates the `jar.properties` file which contains the English version of the jar command's `--help` output. However, no changes have been done to the internationalization files corresponding to this one (for example: `jar_de.properties`), because I don't know what process needs to be followed to have those files updated (if at all they need to be updated).
>
> The commit also includes a jtreg testcase which verifies the usage of this new option.

I think the summary is that we've converged on -C/--dir. We might have to tweak the usage message for -C so that it starts with the existing "Change to the specified directory ..." rather than changing it to start with the extract case.
Are you, or Lance, going to create the CSR for this?

-------------

PR: https://git.openjdk.java.net/jdk/pull/2752
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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Lance Andersen-3


On Mar 27, 2021, at 12:05 PM, Alan Bateman <[hidden email]> wrote:

On Fri, 26 Feb 2021 17:03:11 GMT, Jaikiran Pai <[hidden email]> wrote:

Can I please get a review for this patch which proposes to implement the enhancement request noted in https://bugs.openjdk.java.net/browse/JDK-8173970?

The commit in this PR introduces the `-o` and `--output-dir` option to the `jar` command. The option takes a path to a destination directory as a value and extracts the contents of the jar into that directory. This is an optional option and the changes in the commit continue to maintain backward compatibility where the jar is extracted into current directory, if no `-o` or `--output-dir` option has been specified.

As far as I know, there hasn't been any discussion on what the name of this new option should be. I was initially thinking of using `-d` but that is currently used by the `jar` command for a different purpose. So I decided to use `-o` and `--output-dir`. This is of course open for change depending on any suggestions in this PR.

The commit in this PR also updates the `jar.properties` file which contains the English version of the jar command's `--help` output. However, no changes have been done to the internationalization files corresponding to this one (for example: `jar_de.properties`), because I don't know what process needs to be followed to have those files updated (if at all they need to be updated).

The commit also includes a jtreg testcase which verifies the usage of this new option.

I think the summary is that we've converged on -C/--dir. We might have to tweak the usage message for -C so that it starts with the existing "Change to the specified directory ..." rather than changing it to start with the extract case.
Are you, or Lance, going to create the CSR for this?

I have not had a chance to go through the latest update from Jaikiran or his revised PR yet.

Yes, once we flush everything out, I will work with Jaikiran on the CSR and determine which of us will create the CSR.  On the todo list for next week.

Best




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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Lance Andersen-3
In reply to this post by Lance Andersen-3


On Mar 28, 2021, at 9:24 AM, Jaikiran Pai <[hidden email]> wrote:

Lance ran some tests against the proposed patch and that has exposed an area which we haven't yet taken into account for this feature.

The jar tool has a (hidden) option "-P" which can be used with the "c" (create), "u" (update) and "x" (extract) main operations. When this -P option is used, the jar tool will preserve/won't strip leading slash and ".." component from file name. So imagine a jar created with the -P option as follows:

jar -cfP foo.jar /tmp/blah.txt

This will add /tmp/blah.txt with the the leading / preserved, so the contents of the jar will be:

jar -tf foo.jar
META-INF/
META-INF/MANIFEST.MF
/tmp/blah.txt

Consider being in /home/me/ directory and running the jar -xfP command against this jar. When you do that, the /tmp/blah.txt will get extracted to the /tmp/blah.txt absolute path and the META-INF and the other entries get extracted inside the /home/me/ directory. This is how the jar tool currently behaves when the leading slashes (and ..) are involved with the -P option.

Now coming to this new feature we are talking about, IMO, we cannot break this existing behaviour. So when the user continues to use:

jar -xfP foo.jar

without any explicit -C or --dir option, then IMO, the extract should continue to work just like it does now and continue to extract the /tmp/blah.txt to that absolute location.


Agree 

Now when the user explicitly specifies the new -C or --dir option with the -P option for extract, something like:

jar -xfP foo.jar -C /tmp/hello/

Given the support of -C/-dir is new and -P is there for backwards compatibility then I see the choices are:

  • Issue an error when -P and -C/-dir are specified together with -x
  • Silently ignore the -P option
  • Ignore -C/-dir and the behavior is if -xfP was specified.

I am leaning towards an error given this is a new feature when -P and -C/-dir are specified with -x

Best
Lance

I think we should continue to extract the /tmp/blah.txt to that absolute location instead of making it relative to the /tmp/hello/ directory. Given that -P is a hidden option, I am not sure if this should be documented in some manner (other than maybe code comments), but I wanted to bring this up so that we can come to a decision and have the proposed implementation work in that manner.

-Jaikiran

On 24/03/21 4:10 pm, Jaikiran Pai wrote:
Based on the inputs so far, I've updated the PR to include the provided feedback. Since the PR code review hadn't yet started, I decided to do a force push to the PR so that we can start it afresh.

Command option:

In this current discussion, we seem to have an agreement for using -C and --dir as the short and long options for this feature. The implementation in this PR now uses these options. There was also a suggestion to additionally allow --directory as an option too. I haven't added that yet, since I wasn't sure if we really want that. It was suggested that if we do use --directory, we should "hide" --dir. If we do need the --directory option, I can add that in, in subsequent updates to this PR.


Directories creation:

There was an agreement in our discussion that if the destination directory hierarchy isn't present, then we should create that whole hierarchy and extract the jar into it. The implementation in this PR matches this decision.


Verbose logging:

During the discussion, there was a question whether this feature should introduce any new verbose logs during extraction. IMO, it's a good idea to log the target directory to which the jar is being extracted. So, in the implementation, I have introduced a new (resource bundle backed) verbose log message which prints the absolute path to which the jar will be extracted. Do note that this verbose log message will be printed even if you don't explicitly specify any target directory. i.e. even when the default current directory is used, this verbose log message will be printed if the "-v" option is used.

Repeatability of the newly introduce options:

Unlike in the other main operations of the jar command, the -C option that we use during the extract main operation, IMO, shouldn't be allowed to be used more than once. More specifically the destination directory to which the jar needs to be extracted must only be specified once, irrespective of whether it's through the use of -C or --dir. The code in the PR, explicitly throws an error when such repeatition is encountered.

An alternate approach would have been to allow the -C and/or --dir option to be repeated, but use the last specified value of these options. However, I decided not to pursue that approach, to keep it simple as well as to avoid any confusion on the command usage.


Overwriting of contents in existing target directory:

No specific change has been done when it comes to dealing with the extraction logic itself. Specifically, when the explicitly specified or the default current directory already has directories/files that belong to the jar being extracted, those files/dirs will continue to be overwritten.

Compatibility mode:

The code in this PR also supports the compatibility mode for this option. Specifically, a command like:

jar -xvf somejar.jar -C /tmp/foo/

will work fine and the jar will be extracted into /tmp/foo directory.


Message/error internationalization:

I have only updated the jar.properties for the English version of the new output and error messages. I don't know what the process is for adding this to other languages, if at all that needs to be done in this PR.


jar --help output:

Currently the jar --help output only talks about creation and updation of the jar. There's no mention of using the tool for extracting the jar content:

"jar creates an archive for classes and resources, and can manipulate or
restore individual classes or resources from an archive."

It does mention "manipulate" but doesn't specifically say extraction. The examples in the help command output don't have any examples for extraction. Should we add an example for extracting the jar file, in this help output?


Testing:

A new jtreg test has been introduced which tests various aspects of this feature. It runs most of those tests against both absolute and relative paths.

A couple of tests in the new introduced test case, check for the output/error messages. The jar tool uses resource bundles to print out these messages. I need input on whether I should enforce a specific locale to run these tests so that I can compare the error/output messages for expected strings? See testExtractFailWithMultipleDir() or testHelpOutput() for what I mean.


Man page:

This one I need input on. I have tried to see how these man pages are generated and from what I can understand it looks like these man pages are autogenerated during the build process using pandoc. Is that right? The hints that I see in the Docs.gmk seems to suggest that there are some markdown source files from which these man pages get generated. However, I can't seem to locate any such markdown files for this or other tools, from which the man pages get generated. Any help on how I should go about editing/updating the man page for the jar tool?


Example usage:

Here are some example usages:

jar -x -f somejar.jar -C /tmp/foo/bar/

This command extracts the somejar.jar file to the /tmp/foo/bar/ directory, creating it if necessary.


jar -x -f somejar.jar --dir /tmp/foo/bar/

Same as above, except uses the long form --dir option


jar -x -f somejar.jar -C /tmp/foo/bar/ f1.txt d1/f2.txt

Assuming somejar.jar contains "f1.txt" (at root), "d1/f2.txt" and other files, then the above command extracts only "f1.txt" and "d1/f2.txt" into the /tmp/foo/bar/ directory.


-Jaikiran

On 14/03/21 6:21 pm, Alan Bateman wrote:
On 12/03/2021 12:18, Lance Andersen wrote:

:

I don’t have a strong preference but lean slightly towards ‘-directory’ as it is more descriptive, similar to the other GNU-style commands jar currently supports .  Tar supports ‘—cd’, ‘—directory’ in addition to ‘-C’ which is why I suggested supporting  both GNU-style long options.

Perhaps jpackage should also support —dir/directory in addition to ‘—dest' if we are looking at consistency between java tools.

I do agree that it would be nice to be consistent across the java tools for options so if we go the ‘-directory’, we should follow your suggestion and make it the primary and remove ‘—dir’ from the usage output.
My comment on consistency was limited to the long option to specify the directory when extracting, didn't mean to suggest doing anything with the other tools that specify an output/destination directory. In any case, I think we have enough to make progress on this issue now.

-Alan





Lance Andersen| Principal Member of Technical Staff | +1.781.442.2037
Oracle Java Engineering 
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Burlington, MA 01803
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Re: RFR: 8173970: jar tool should have a way to extract to a directory

Jaikiran Pai


On 28/03/21 9:52 pm, Lance Andersen wrote:


On Mar 28, 2021, at 9:24 AM, Jaikiran Pai <[hidden email]> wrote:


Now when the user explicitly specifies the new -C or --dir option with the -P option for extract, something like:

jar -xfP foo.jar -C /tmp/hello/

Given the support of -C/-dir is new and -P is there for backwards compatibility then I see the choices are:

  • Issue an error when -P and -C/-dir are specified together with -x
  • Silently ignore the -P option
  • Ignore -C/-dir and the behavior is if -xfP was specified.

I am leaning towards an error given this is a new feature when -P and -C/-dir are specified with -x

That sounds reasonable to me. I'll update the PR accordingly to take this into account.

-Jaikiran


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Re: RFR: 8173970: jar tool should have a way to extract to a directory [v3]

Jaikiran Pai-3
In reply to this post by Jaikiran Pai-3
> Can I please get a review for this patch which proposes to implement the enhancement request noted in https://bugs.openjdk.java.net/browse/JDK-8173970?
>
> The commit in this PR introduces the `-o` and `--output-dir` option to the `jar` command. The option takes a path to a destination directory as a value and extracts the contents of the jar into that directory. This is an optional option and the changes in the commit continue to maintain backward compatibility where the jar is extracted into current directory, if no `-o` or `--output-dir` option has been specified.
>
> As far as I know, there hasn't been any discussion on what the name of this new option should be. I was initially thinking of using `-d` but that is currently used by the `jar` command for a different purpose. So I decided to use `-o` and `--output-dir`. This is of course open for change depending on any suggestions in this PR.
>
> The commit in this PR also updates the `jar.properties` file which contains the English version of the jar command's `--help` output. However, no changes have been done to the internationalization files corresponding to this one (for example: `jar_de.properties`), because I don't know what process needs to be followed to have those files updated (if at all they need to be updated).
>
> The commit also includes a jtreg testcase which verifies the usage of this new option.

Jaikiran Pai has updated the pull request incrementally with two additional commits since the last revision:

 - Alan's review feedback for -C help text
 - Keep -xfP backward compatible but don't allow -C/--dir with -xfP

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2752/files
  - new: https://git.openjdk.java.net/jdk/pull/2752/files/a9954240..3df602d2

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2752&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2752&range=01-02

  Stats: 88 lines in 3 files changed: 78 ins; 3 del; 7 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2752.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2752/head:pull/2752

PR: https://git.openjdk.java.net/jdk/pull/2752