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 # Developing GCLI

 ## About the code

 The majority of the GCLI source is stored in the ``lib`` directory.

 The ``docs`` directory contains documentation.

 The ``scripts`` directory contains RequireJS that GCLI uses.

 The ``build`` directory contains files used when creating builds.

 The ``mozilla`` directory contains the mercurial patch queue of patches to apply

 to mozilla-central.

 The ``selenium-tests`` directory contains selenium web-page integration tests.

 The source in the ``lib`` directory is split into 4 sections:

 - ``lib/demo`` contains commands used in the demo page. It is not needed except

   for demo purposes.

 - ``lib/test`` contains a small test harness for testing GCLI.

 - ``lib/gclitest`` contains tests that run in the test harness

 - ``lib/gcli`` contains the actual meat

 GCLI is split into a UI portion and a Model/Controller portion.

 ## The GCLI Model

 The heart of GCLI is a ``Requisition``, which is an AST for the input. A

 ``Requisition`` is a command that we'd like to execute, and we're filling out

 all the inputs required to execute the command.

 A ``Requisition`` has a ``Command`` that is to be executed. Each Command has a

 number of ``Parameter``s, each of which has a name and a type as detailed

 above.

 As you type, your input is split into ``Argument``s, which are then assigned to

 ``Parameter``s using ``Assignment``s. Each ``Assignment`` has a ``Conversion``

 which stores the input argument along with the value that is was converted into

 according to the type of the parameter.

 There are special assignments called ``CommandAssignment`` which the

 ``Requisition`` uses to link to the command to execute, and

 ``UnassignedAssignment``used to store arguments that do not have a parameter

 to be assigned to.

 ## The GCLI UI

 There are several components of the GCLI UI. Each can have a script portion,

 some template HTML and a CSS file. The template HTML is processed by

 ``domtemplate`` before use.

 DomTemplate is fully documented in [it's own repository]

 (https://github.com/joewalker/domtemplate).

 The components are:

 - ``Inputter`` controls the input field, processing special keyboard events and

   making sure that it stays in sync with the Requisition.

 - ``Completer`` updates a div that is located behind the input field and used

   to display completion advice and hint highlights. It is stored in

   completer.js.

 - ``Display`` is responsible for containing the popup hints that are displayed

   above the command line. Typically Display contains a Hinter and a RequestsView

   although these are not both required. Display itself is optional, and isn't

   planned for use in the first release of GCLI in Firefox.

 - ``Hinter`` Is used to display input hints. It shows either a Menu or an

   ArgFetch component depending on the state of the Requisition

 - ``Menu`` is used initially to select the command to be executed. It can act

   somewhat like the Start menu on windows.

 - ``ArgFetch`` Once the command to be executed has been selected, ArgFetch

   shows a 'dialog' allowing the user to enter the parameters to the selected

   command.

 - ``RequestsView`` Contains a set of ``RequestView`` components, each of which

   displays a command that has been invoked. RequestsView is a poor name, and

   should better be called ReportView

 ArgFetch displays a number of Fields. There are fields for most of the Types

 discussed earlier. See 'Writing Fields' above for more information.

 ## Testing

 GCLI contains 2 test suites:

 - JS level testing is run with the ``test`` command. The tests are located in

   ``lib/gclitest`` and they use the test runner in ``lib/test``. This is fairly

   comprehensive, however it does not do UI level testing.

   If writing a new test it needs to be registered in ``lib/gclitest/index``.

   For an example of how to write tests, see ``lib/gclitest/testSplit.js``.

   The test functions are implemented in ``lib/test/assert``.

 - Browser integration tests are included in ``browser_webconsole_gcli_*.js``,

   in ``toolkit/components/console/hudservice/tests/browser``. These are

   run with the rest of the Mozilla test suite.

 ## Coding Conventions

 The coding conventions for the GCLI project come from the Bespin/Skywriter and

 Ace projects. They are roughly [Crockford]

 (http://javascript.crockford.com/code.html) with a few exceptions and

 additions:

 * ``var`` does not need to be at the top of each function, we'd like to move

   to ``let`` when it's generally available, and ``let`` doesn't have the same

   semantic twists as ``var``.

 * Strings are generally enclosed in single quotes.

 * ``eval`` is to be avoided, but we don't declare it evil.

 The [Google JavaScript conventions]

 (https://google-styleguide.googlecode.com/svn/trunk/javascriptguide.xml) are

 more detailed, we tend to deviate in:

 * Custom exceptions: We generally just use ``throw new Error('message');``

 * Multi-level prototype hierarchies: Allowed; we don't have ``goog.inherits()``

 * ``else`` begins on a line by itself:

         if (thing) {

           doThis();

         }

         else {

           doThat();

         }

 ## Startup

 Internally GCLI modules have ``startup()``/``shutdown()`` functions which are

 called on module init from the top level ``index.js`` of that 'package'.

 In order to initialize a package all that is needed is to require the package

 index (e.g. ``require('package/index')``).

 The ``shutdown()`` function was useful when GCLI was used in Bespin as part of

 dynamic registration/de-registration. It is not known if this feature will be

 useful in the future. So it has not been entirely removed, it may be at some

 future date.

 ## Running the Unit Tests

 Start the GCLI static server:

     cd path/to/gcli

     node gcli.js

 Now point your browser to http://localhost:9999/localtest.html. When the page

 loads the tests will be automatically run outputting to the console, or you can

 enter the ``test`` command to run the unit tests.

 ## Contributing Code

 Please could you do the following to help minimize the amount of rework that we

 do:

 1. Check the unit tests run correctly (see **Running the Unit Tests** above)

 2. Check the code follows the style guide. At a minimum it should look like the

    code around it. For more detailed notes, see **Coding Conventions** above

 3. Help me review your work by using good commit comments. Which means 2 things

    * Well formatted messages, i.e. 50 char summary including bug tag, followed

      by a blank line followed by a more in-depth message wrapped to 72 chars

      per line. This is basically the format used by the Linux Kernel. See the

      [commit log](https://github.com/joewalker/gcli/commits/master) for

      examples. The be extra helpful, please use the "shortdesc-BUGNUM: " if

      possible which also helps in reviews.

    * Commit your changes as a story. Make it easy for me to understand the

      changes that you've made.

 4. Sign your work. To improve tracking of who did what, we follow the sign-off

    procedure used in the Linux Kernel.

    The sign-off is a simple line at the end of the explanation for the

    patch, which certifies that you wrote it or otherwise have the right to

    pass it on as an open-source patch.  The rules are pretty simple: if you

    can certify the below:

         Developer's Certificate of Origin 1.1

         By making a contribution to this project, I certify that:

         (a) The contribution was created in whole or in part by me and I

             have the right to submit it under the open source license

             indicated in the file; or

         (b) The contribution is based upon previous work that, to the best

             of my knowledge, is covered under an appropriate open source

             license and I have the right under that license to submit that

             work with modifications, whether created in whole or in part

             by me, under the same open source license (unless I am

             permitted to submit under a different license), as indicated

             in the file; or

         (c) The contribution was provided directly to me by some other

             person who certified (a), (b) or (c) and I have not modified

             it.

         (d) I understand and agree that this project and the contribution

             are public and that a record of the contribution (including all

             personal information I submit with it, including my sign-off) is

             maintained indefinitely and may be redistributed consistent with

             this project or the open source license(s) involved.

    then you just add a line saying

         Signed-off-by: Random J Developer <random@developer.example.org>

    using your real name (sorry, no pseudonyms or anonymous contributions.)

 Thanks for wanting to contribute code.