# Using wraptool

Wraptool is a subcommand of Meson that allows you to manage your
source dependencies using the WrapDB database. It gives you all things
you would expect, such as installing and updating dependencies. The
wrap tool works on all platforms, the only limitation is that the wrap
definition works on your target platform. If you find some Wraps that
don't work, please file bugs or, even better, patches.

All code examples here assume that you are running the commands in
your top level source directory. Lines that start with the `$` mark
are commands to type.

## Simple querying

The simplest operation to do is to query the list of packages
available. To list them all issue the following command:

    $ meson wrap list
    box2d
    enet
    gtest
    libjpeg
    liblzma
    libpng
    libxml2
    lua
    ogg
    sqlite
    vorbis
    zlib

Usually you want to search for a specific package. This can be done
with the `search` command:

    $ meson wrap search jpeg
    libjpeg

To determine which versions of libjpeg are available to install, issue
the `info` command:

    $ meson wrap info libjpeg
    Available versions of libjpeg:
      9a 2

The first number is the upstream release version, in this case
`9a`. The second number is the Wrap revision number. They don't relate
to anything in particular, but larger numbers imply newer
releases. You should always use the newest available release.

## Installing dependencies

Installing dependencies is just as straightforward. First just create
the `subprojects` directory at the top of your source tree and issue
the install command.

    $ meson wrap install libjpeg
    Installed libjpeg branch 9a revision 2

Now you can issue a `subproject('libjpeg')` in your `meson.build` file
to use it.

To check if your projects are up to date you can issue the `status` command.

    $ meson wrap status
    Subproject status
     libjpeg up to date. Branch 9a, revision 2.
     zlib not up to date. Have 1.2.8 2, but 1.2.8 4 is available.

In this case `zlib` has a newer release available. Updating it is
straightforward:

    $ meson wrap update zlib
    Updated zlib to branch 1.2.8 revision 4

Wraptool can do other things besides these. Documentation for these
can be found in the command line help, which can be accessed by
`meson wrap --help`.

## Promoting dependencies

Meson will only search for subprojects from the top level
`subprojects` directory. If you have subprojects that themselves have
subprojects, you must transfer them to the top level. This can be done
by going to your source root and issuing a promotion command.

    meson wrap promote projname

This will cause Meson to go through your entire project tree, find an
embedded subproject and copy it to the top level.

If there are multiple embedded copies of a subproject, Meson will not
try to guess which one you want. Instead it will print all the
possibilities. You can then manually select which one to promote by
writing it out fully.

    meson wrap promote subprojects/s1/subprojects/projname

This functionality was added in Meson release 0.45.0.
